Last data update: May 06, 2024. (Total: 46732 publications since 2009)
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Protection and antibody levels 35 years after primary series with hepatitis B vaccine and response to a booster dose
Bruce MG , Bruden D , Hurlburt D , Morris J , Bressler S , Thompson G , Lecy D , Rudolph K , Bulkow L , Hennessy T , Simons BC , Weng MK , Nelson N , McMahon BJ . Hepatology 2022 76 (4) 1180-1189 BACKGROUND: The duration of protection from hepatitis B vaccination in children and adults is not known. In 1981, we used three doses of plasma-derived hepatitis B vaccine to immunize a cohort of 1578 Alaska Native adults and children from 15 Alaska communities who were 6 months or older. METHODS: We tested persons for anti-HBs levels 35 years after receiving the primary series. Those with levels <10 mIU/ml received 1 booster dose of recombinant hepatitis B vaccine 2-4 weeks later and were then evaluated on the basis of anti-HBs measurements 30 days post-booster. RESULTS: Among the 320 recruited, 112 persons had not participated in the 22 nor 30-year follow-up study (Group 1) and 208 persons had participated but were not given an HBV booster dose (Group 2). Among the 112 persons in Group 1 who responded to the original primary series, 53 (47.3%) had an anti-HBs level ≥10 mIU/ml. Among group 1, 73.7% (28/38) of persons available for a booster dose responded to it with an anti-HBs level ≥10 mIU/ml at 30 days. Initial anti-HBs level after the primary series was correlated with higher anti-HBs levels at 35 years. Among 8 persons who tested positive for anti-HBc, none tested positive for HBsAg nor HBV DNA. CONCLUSIONS: Based on anti-HBs level ≥10 mIU/ml at 35 years and a 73.7% booster dose response, we estimate 86% of participants had evidence of protection 35 years later. Booster doses are not needed in the general population at this time. |
Virus decay rates should not be used to reduce recommended room air clearance times
Lindsley WG , Martin SB , Mead KR , Hammond DR . Infect Control Hosp Epidemiol 2021 43 (12) 1-2 We read with concern the letter by Hurlburt et al Reference Hurlburt, DeKleer and Bryce1 proposing revisions to the recommended room air clearance times for infectious aerosols in healthcare facilities. We believe that the calculations performed to justify the changes are based on flawed assumptions and an erroneous calculation. Experimental data on the survival of airborne SARS-CoV-2 virus and the dynamics of room ventilation do not support their conclusions. |
A prospective cohort study of immunogenicity of quadrivalent human papillomavirus vaccination among Alaska Native Children, Alaska, United States
Bruce MG , Meites E , Bulkow L , Panicker G , Hurlburt D , Lecy D , Thompson G , Rudolph K , Unger ER , Hennessy T , Markowitz LE . Vaccine 2020 38 (42) 6585-6591 OBJECTIVE: In the United States, HPV vaccination is routinely recommended at age 11 or 12 years; the series can be started at age 9. We conducted a cohort study to assess long-term immunogenicity of quadrivalent HPV vaccine (4vHPV) in an American Indian/Alaska Native (AI/AN) Indigenous population. METHODS: During 2011-2014, we enrolled AI/AN girls and boys aged 9-14 years, who were vaccinated with a 3-dose series of 4vHPV. Serum specimens were collected at five time points: immediately prior to doses 2 and 3, and at one month, one year, and two years after series completion. Antibody testing was performed using a multiplex virus-like-particle-IgG ELISA for 4vHPV types (HPV 6/11/16/18). RESULTS: Among 477 children (405 girls/72 boys) completing the 3-dose series, median age at enrollment was 11.2 years. Of the 477, 72 (15%) were tested before dose 2 and 70 (15%) before dose 3. Following series completion, 435 (91%) were tested at one month, 382 (80%) at one year, and 351 (74%) at two years. All tested participants had detectable antibody to 4vHPV types at all time points measured. Geometric mean concentrations (GMCs) for 4vHPV types at one month and two years post-series completion were 269.9 and 32.7 AU/ml for HPV6, 349.3 and 42.9 AU/ml for HPV11, 1240.2 and 168.3 IU/ml HPV16, and 493.2 and 52.2 IU/ml for HPV18. Among children tested after each dose, GMCs after doses 1 and 2 were 3.9 and 32.2 AU/ml for HPV6, 5.3 and 45.6 AU/ml for HPV11, 20.8 and 187.9 IU/ml for HPV16; and 6.6 and 49.7 IU/ml for HPV18. No serious adverse events were reported. CONCLUSION: All AI/AN children developed antibodies to all 4vHPV types after vaccination. GMCs rose after each dose, then decreased to a plateau over the subsequent two years. This cohort will continue to be followed to determine duration of antibody response. |
Haemophilus influenzae serotype a (Hia) carriage in a small Alaska community after a cluster of invasive Hia disease, 2018
Nolen LD , Tiffany A , DeByle C , Bruden D , Thompson G , Reasonover A , Hurlburt D , Mosites E , Simons BC , Klejka J , Castrodale L , McLaughlin J , Bruce MG . Clin Infect Dis 2020 73 (2) e280-e286 BACKGROUND: Between May and July 2018, four invasive Haemophilus influenzae serotype a (iHia) infections occurred in a remote Alaska community. We performed a public health response to prevent further illness and understand Hia carriage in the community. METHODS: We collected oropharyngeal (OP) samples community-wide from untreated individuals to evaluate baseline carriage. Risk factor data was collected by interview. To prevent additional illness, we offered prophylactic rifampin to individuals in contact with iHia patients (contacts) and to all children aged <10 years. OP samples were collected again eight weeks post-rifampin distribution. Samples were tested using real-time PCR and culture. RESULTS: At baseline, Hia was carried by 4/27 (14.8%) contacts and 7/364 (1.9%) non-contacts (p<0.01). Contacts aged <10 years were more likely to carry Hia at any timepoint (11/18, 61%) than contacts aged >/=10 years (3/34, 8.8%) or non-contacts aged <10 years (2/139, 1.4%) and >/=10 years (6/276, 2.2%)(p<0.001 for all). Hia carriers were clustered in nine households (7% of total households). At the household level, carriage was associated with households with >/=1 contact (PR=5.6, CI:1.3-21.6), crowding (PR=7.7, CI:1.1-199.5) and >/=3 tobacco users (PR=5.0, CI:1.2-19.6). Sixty-six percent (40/61) of contacts and 90% (111/124) of non-contacts aged <10 years received rifampin. Elevated carriage prevalence persisted in contacts when retested eight weeks after rifampin distribution (contacts 6/25 (24%), non-contacts 2/114 (1.8%), p<0.001). CONCLUSIONS: Hia carriage prevalence was significantly higher among people who had contact with iHia patients than the general community. Rifampin prophylaxis did not result in a reduction of Hia carriage prevalence in this community. |
Presence of cagPAI genes and characterization of vacA s, i and m regions in Helicobacter pylori isolated from Alaskans and their association with clinical pathologies.
Miernyk KM , Bruden D , Rudolph KM , Hurlburt DA , Sacco F , McMahon BJ , Bruce MG . J Med Microbiol 2020 69 (2) 218-227 Introduction. Gastric cancer is a health disparity in the Alaska Native people. The incidence of Helicobacter pylori infection, a risk factor for non-cardia gastric adenocarcinoma, is also high. Gastric cancer is partially associated with the virulence of the infecting strain.Aim. To genotype the vacA s, m and i and cag pathogenicity island (cagPAI) genes in H. pylori from Alaskans and investigate associations with gastropathy.Methodology. We enrolled patients with gastritis, peptic ulcer disease (PUD) and intestinal metaplasia (IM) in 1998-2005 and patients with gastric cancer in 2011-2013. Gastric biopsies were collected and cultured and PCR was performed to detect the presence of the right and left ends of the cagPAI, the cagA, cagE, cagT and virD4 genes and to genotype the vacA s, m and i regions.Results. We recruited 263 people; 22 (8 %) had no/mild gastritis, 121 (46 %) had moderate gastritis, 40 (15%) had severe gastritis, 38 (14 %) had PUD, 30 (11 %) had IM and 12 (5 %) had gastric cancer. H. pylori isolates from 150 (57%) people had an intact cagPAI; those were associated with a more severe gastropathy (P</=0.02 for all comparisons). H. pylori isolates from 77 % of people had either the vacA s1/i1/m1 (40 %; 94/234) or s2/i2/m2 (37 %; 86/234) genotype. vacA s1/i1/m1 was associated with a more severe gastropathy (P</=0.03 for all comparisons).Conclusions. In this population with high rates of gastric cancer, we found that just over half of the H. pylori contained an intact cagPAI and 40 % had the vacA s1/i1/m1 genotype. Infection with these strains was associated with a more severe gastropathy. |
The relationship between previous antimicrobial use, antimicrobial resistance and treatment outcome among Alaskans treated for Helicobacter pylori infection
Bruce MG , Bruden D , Newbrough D , Hurlburt DA , Hennessy TW , Morris JM , Reasonover AL , Sacco F , McMahon BJ . GastroHep 2019 1 (4) 172-179 Background: Helicobacter pylori isolates from Alaska have demonstrated a high prevalence of antimicrobial resistance. Objective(s): To determine treatment failure in three groups, and analyse the relationship between treatment failure and antimicrobial resistance. Method(s): Antimicrobial susceptibility was determined using agar dilution and Etest. Treatment success was determined using the urea breath test 2 months after antimicrobial therapy. Result(s): Among 303 treated adult patients, 103 (34%) failed initial treatment despite a 91% compliance with medication. About 222 (73%) patients were treated with a clarithromycin-based regimen, 55 (18%) with a metronidazole-based regimen, 15 (5%) with a regimen that contained clarithromycin and metronidazole and 11 (4%) with other antimicrobials. Among 260 culture-positive patients, 156 (60%) were infected with metronidazole-resistant isolates, 74 (28%) clarithromycin-resistant, 52 (20%) clarithromycin/metronidazole-resistant, 40 (15%) levofloxacin-resistant, 11 (4%) clarithromycin/metronidazole/levofloxacin-resistant and nine (3%) amoxicillin-resistant. Overall, 34% of patients were treated with at least one antibiotic to which their infecting organism was resistant. Among patients treated with clarithromycin-based regimens, treatment failed in 72% of patients carrying clarithromycin-resistant H pylori vs 20% with clarithromycin-sensitive strains (RR = 3.7, P < 0.001). Among patients treated with metronidazole-based regimens, treatment failed in 19% of patients carrying metronidazole-resistant H pylori vs 24% with metronidazole-sensitive strains (P = 0.72). Conclusion(s): A high proportion of H pylori isolates demonstrate resistance to clarithromycin, metronidazole or levofloxacin. Over one third of H pylori-infected patients were treated with an antibiotic to which their infecting organism demonstrated resistance. Clarithromycin resistance is associated with a greater risk for failure with clarithromycin-based multidrug regimens compared to clarithromycin-sensitive; resistance to metronidazole did not affect treatment failure. |
Human seroprevalence to 11 zoonotic pathogens in the U.S. Arctic, Alaska
Miernyk KM , Bruden D , Parkinson AJ , Hurlburt D , Klejka J , Berner J , Stoddard RA , Handali S , Wilkins PP , Kersh GJ , Fitzpatrick K , Drebot MA , Priest JW , Pappert R , Petersen JM , Teshale E , Hennessy TW , Bruce MG . Vector Borne Zoonotic Dis 2019 19 (8) 563-575 BACKGROUND: Due to their close relationship with the environment, Alaskans are at risk for zoonotic pathogen infection. One way to assess a population's disease burden is to determine the seroprevalence of pathogens of interest. The objective of this study was to determine the seroprevalence of 11 zoonotic pathogens in people living in Alaska. METHODS: In a 2007 avian influenza exposure study, we recruited persons with varying wild bird exposures. Using sera from this study, we tested for antibodies to Cryptosporidium spp., Echinococcus spp., Giardia intestinalis, Toxoplasma gondii, Trichinella spp., Brucella spp., Coxiella burnetii, Francisella tularensis, California serogroup bunyaviruses, and hepatitis E virus (HEV). RESULTS: Eight hundred eighty-seven persons had sera tested, including 454 subsistence bird hunters and family members, 160 sport bird hunters, 77 avian wildlife biologists, and 196 persons with no wild bird exposure. A subset (n = 481) of sera was tested for California serogroup bunyaviruses. We detected antibodies to 10/11 pathogens. Seropositivity to Cryptosporidium spp. (29%), California serotype bunyaviruses (27%), and G. intestinalis (19%) was the most common; 63% (301/481) of sera had antibodies to at least one pathogen. Using a multivariable logistic regression model, Cryptosporidium spp. seropositivity was higher in females (35.7% vs. 25.0%; p = 0.01) and G. intestinalis seropositivity was higher in males (21.8% vs. 15.5%; p = 0.02). Alaska Native persons were more likely than non-Native persons to be seropositive to C. burnetii (11.7% vs. 3.8%; p = 0.005) and less likely to be seropositive to HEV (0.4% vs. 4.1%; p = 0.01). Seropositivity to Cryptosporidium spp., C. burnetii, HEV, and Echinococcus granulosus was associated with increasing age (p </= 0.01 for all) as was seropositivity to >/=1 pathogen (p < 0.0001). CONCLUSION: Seropositivity to zoonotic pathogens is common among Alaskans with the highest to Cryptosporidium spp., California serogroup bunyaviruses, and G. intestinalis. This study provides a baseline for use in assessing seroprevalence changes over time. |
H. pylori-associated pathologic findings among Alaska native patients
Nolen LD , Bruden D , Miernyk K , McMahon BJ , Sacco F , Varner W , Mezzetti T , Hurlburt D , Tiesinga J , Bruce MG . Int J Circumpolar Health 2018 77 (1) 1510715 Helicobacter pylori infection is common among Alaska native (AN) people, however scant gastric histopathologic data is available for this population. This study aimed to characterise gastric histopathology and H. pylori infection among AN people. We enrolled AN adults undergoing upper endoscopy. Gastric biopsy samples were evaluated for pathologic changes, the presence of H. pylori, and the presence of cag pathogenicity island-positive bacteria. Of 432 persons; two persons were diagnosed with gastric adenocarcinoma, two with MALT lymphoma, 40 (10%) with ulcers, and 51 (12%) with intestinal metaplasia. Fifty-five per cent of H. pylori-positive persons had cag pathogenicity island positive bacteria. The gastric antrum had the highest prevalence of acute and chronic moderate-severe gastritis. H. pylori-positive persons were 16 and four times more likely to have moderate-severe acute gastritis and chronic gastritis (p < 0.01), respectively. An intact cag pathogenicity island positive was correlated with moderate-severe acute antral gastritis (53% vs. 31%, p = 0.0003). H. pylori-positive persons were more likely to have moderate-severe acute and chronic gastritis compared to H. pylori-negative persons. Gastritis and intestinal metaplasia were most frequently found in the gastric antrum. Intact cag pathogenicity island positive was correlated with acute antral gastritis and intestinal metaplasia. |
Antimicrobial resistance among Helicobacter pylori isolates in Alaska, 2000-2016
Mosites E , Bruden D , Morris J , Reasonover A , Rudolph K , Hurlburt D , Hennessy T , McMahon B , Bruce M . J Glob Antimicrob Resist 2018 15 148-153 OBJECTIVES: Alaska Native people experience a high burden of Helicobacter pylori infection and concomitant high rates of gastric cancer. Additionally, the prevalence of antimicrobial resistant strains of H. pylori has been shown to be high in Alaska. We evaluated antimicrobial resistance over time among sentinel surveillance isolates and assessed risk factors for carrying resistant H. pylori. METHODS: Through Alaska's H. pylori sentinel surveillance system, we collected and cultured antral and fundal biopsies from Alaska Native patients undergoing esophagogastroduodenoscopy for clinical indications during 2000-2016. For positive cultures, we performed minimum inhibitory concentration (MIC) testing for metronidazole, amoxicillin, clarithromycin, tetracycline, and levofloxacin. RESULTS: We tested 800H. pylori isolates obtained from 763 patients. Metronidazole resistance was most common (342/800; 43%), followed by clarithromycin resistance (238/800; 30%), resistance to both clarithromycin and metronidazole (128/800; 16%), and levofloxacin resistance (113/800; 15%). Low proportions of isolates were resistant to amoxicillin and tetracycline. Levofloxacin resistance increased between 2000 and 2016 (p <0.001), but resistance to other antimicrobials did not change over time. Metronidazole and clarithromycin resistance were more common among women (p <0.001 for both), while levofloxacin resistance was more common among those with an urban residence (p=0.003). Metronidazole resistance and levofloxacin resistance were more common among older patients (p=0.004, p=0.012). CONCLUSION: Between 2000 and 2016, a large percentage of the H. pylori isolates received by the Alaska Sentinel Surveillance System demonstrated resistance to common antimicrobial agents. The surveillance system provides valuable information for clinicians to make informed treatment choices for patient with H. pylori. |
Giardia and Cryptosporidium antibody prevalence and correlates of exposure among Alaska residents, 2007-2008
Mosites E , Miernyk K , Priest JW , Bruden D , Hurlburt D , Parkinson A , Klejka J , Hennessy T , Bruce MG . Epidemiol Infect 2018 146 (7) 1-7 Giardia duodenalis and Cryptosporidium spp. are common intestinal protozoa that can cause diarrhoeal disease. Although cases of infection with Giardia and Cryptosporidium have been reported in Alaska, the seroprevalence and correlates of exposure to these parasites have not been characterised. We conducted a seroprevalence survey among 887 residents of Alaska, including sport hunters, wildlife biologists, subsistence bird hunters and their families and non-exposed persons. We tested serum using a multiplex bead assay to evaluate antibodies to the Giardia duodenalis variant-specific surface protein conserved structural regions and to the Cryptosporidium parvum 17- and 27-kDa antigens. Approximately one third of participants in each group had evidence of exposure to Cryptosporidium. Prevalence of Giardia antibody was highest among subsistence hunters and their families (30%), among whom positivity was associated with lack of community access to in-home running water (adjusted prevalence ratio [aPR] 1.15, 95% confidence interval (CI) 1.02-1.28) or collecting rain, ice, or snow to use as drinking water (aPR 1.09, 95% CI 1.01-1.18). Improving in-home water access for entire communities could decrease the risk of exposure to Giardia. |
Outbreak of invasive infections from subtype emm26.3 group A Streptococcus among homeless adults-Anchorage, Alaska, 2016-2017.
Mosites E , Frick A , Gounder P , Castrodale L , Li Y , Rudolph K , Hurlburt D , Lecy KD , Zulz T , Adebanjo T , Onukwube J , Beall B , Van Beneden CA , Hennessy T , McLaughlin J , Bruce MG . Clin Infect Dis 2018 66 (7) 1068-1074 Background: In 2016, we detected an outbreak of group A Streptococcus (GAS) invasive infections among the estimated 1000 persons experiencing homelessness (PEH) in Anchorage, Alaska. We characterized the outbreak and implemented a mass antibiotic intervention at homeless service facilities. Methods: We identified cases through the Alaska GAS laboratory-based surveillance system. We conducted emm typing, antimicrobial susceptibility testing, and whole-genome sequencing on all invasive isolates and compared medical record data of patients infected with emm26.3 and other emm types. In February 2017, we offered PEH at 6 facilities in Anchorage a single dose of 1 g of azithromycin. We collected oropharyngeal and nonintact skin swabs on a subset of participants concurrent with the intervention and 4 weeks afterward. Results: From July 2016 through April 2017, we detected 42 invasive emm26.3 cases in Anchorage, 35 of which were in PEH. The emm26.3 isolates differed on average by only 2 single-nucleotide polymorphisms. Compared to other emm types, infection with emm26.3 was associated with cellulitis (odds ratio [OR], 2.5; P = .04) and necrotizing fasciitis (OR, 4.4; P = .02). We dispensed antibiotics to 391 PEH. Colonization with emm26.3 decreased from 4% of 277 at baseline to 1% of 287 at follow-up (P = .05). Invasive GAS incidence decreased from 1.5 cases per 1000 PEH/week in the 6 weeks prior to the intervention to 0.2 cases per 1000 PEH/week in the 6 weeks after (P = .01). Conclusions: In an invasive GAS outbreak in PEH in Anchorage, mass antibiotic administration was temporally associated with reduced invasive disease cases and colonization prevalence. |
Prevalence of Helicobacter pylori among Alaskans: Factors associated with infection and comparison of urea breath test and anti-Helicobacter pylori IgG antibodies
Miernyk KM , Bulkow LR , Gold BD , Bruce MG , Hurlburt DH , Griffin PM , Swerdlow DL , Cook K , Hennessy TW , Parkinson AJ . Helicobacter 2018 23 (3) e12482 BACKGROUND: Helicobacter pylori is one of the most common human infections in the world, and studies in Alaska Native people, as well as other Indigenous peoples, have shown a high prevalence of this gastric infection. This study was undertaken to determine the prevalence of H. pylori infection by urea breath test (UBT) and anti- H. pylori IgG among Alaskans living in four regions of the state and to identify factors associated with infection. METHODS: A convenience sample of persons > 6 months old living in five rural and one urban Alaskan community were recruited from 1996 to 1997. Participants were asked about factors possibly associated with infection. Sera were collected and tested for anti- H. pylori IgG antibodies; a UBT was administered to participants > 5 years old. RESULTS: We recruited 710 people of whom 571 (80%) were Alaska Native and 467 (66%) were from rural communities. Rural residents were more likely to be Alaska Native compared with urban residents (P < .001). Of the 710 people, 699 (98%) had a serum sample analyzed, and 634 (97%) persons > 5 years old had a UBT performed. H. pylori prevalence was 69% by UBT and 68% by anti- H. pylori IgG. Among those with a result for both tests, there was 94% concordance. Factors associated with H. pylori positivity were Alaska Native racial status, age >/= 20 years, rural region of residence, living in a crowded home, and drinking water that was not piped or delivered. CONCLUSIONS: Helicobacter pylori prevalence is high in Alaska, especially in Alaska Native persons and rural residents. Concordance between UBT and serology was also high in this group. Two socioeconomic factors, crowding and drinking water that was not piped or delivered, were found to be associated with H. pylori positivity. |
Re-emergence of pneumococcal colonization by vaccine serotype 19F in persons aged 5 years after 13-valent pneumococcal conjugate vaccine introduction-Alaska, 2008-2013
Gounder PP , Bruden D , Rudolph K , Zulz T , Hurlburt D , Thompson G , Bruce MG , Hennessy TW . Vaccine 2017 36 (5) 691-697 BACKGROUND: The pneumococcal conjugate vaccine (PCV) was introduced in 2001. Widespread PCV use nearly eradicated pneumococcal colonization by vaccine serotypes. Since 2008, however, colonization by PCV-serotype 19F has increased in Alaska residents. We describe the epidemiology of re-emerging serotype 19F colonization. METHODS: We conducted annual cross-sectional colonization surveys from 2008 to 2013. We recruited children aged <5years at 2 urban clinics and participants of all ages from Region-A (2 villages), Region-B (4 villages), and Region-C (2 villages). We interviewed participants and reviewed their medical records to obtain demographic information and determine PCV status. We obtained nasopharyngeal swab specimens from participants to identify pneumococci and to determine the pneumococcal serotype, antimicrobial resistance, and multilocus sequence type. We used the Cochran-Armitage test to assess for significant trends in colonization across time periods. RESULTS: Among participants aged <5years, pneumococcal serotype 19F colonization remained unchanged from 2008-2009 (0.7%) to 2012-2013 (0.5%; P-value [P]=.54). Serotype 19F colonization increased from 2008-2009 to 2012-2013 among participants aged 5-11years (0.3% to 3.2%; P<.01), participants 12-17years (0.0% to 2.0%; P<.01), and participants aged >/=18years (0.1% to 0.5%; P<.01). During 2012-2013, 85 (93%) of 91 pneumococcal serotype 19F isolates were identified among participants from Region B; the majority of serotype 19F isolates belonged to an antimicrobial nonsusceptibility pattern corresponding to a novel multilocus sequence type 9074. CONCLUSIONS: PCV continues to protect against serotype 19F colonization in vaccinated children aged <5years. The direct PCV impact on serotype 19F colonization in persons aged 5-11years and indirect impact in persons aged >/=12years is waning, possibly because of a newly introduced genotype in Region-B. |
Population structure of invasive Streptococcus pneumoniae isolates among Alaskan children in the conjugate vaccine era, 2001 to 2013.
Miernyk KM , Bulkow LR , Case SL , Zulz T , Bruce MG , Harker-Jones M , Hurlburt DA , Hennessy TW , Rudolph KM . Diagn Microbiol Infect Dis 2016 86 (2) 224-30 Here we describe the relationships between serotypes, genotypes, and antimicrobial susceptibility among isolates causing invasive pneumococcal disease in Alaskan children during the pneumococcal conjugate vaccine (PCV) era. From 2001 to 2013 we received 271 isolates representing 33 serotypes. The most common serotypes were 19A (29.5%, n= 80), 7F (12.5%, n= 34), 15B/C (6.3%, n= 17), and 22F (4.8%, n= 13). Multilocus sequence typing identified 11 clonal complexes (CC) and 45 singletons. Five CCs accounted for 52% (141/271) of the total: CC199 (21% [n= 57], serotypes 19A, 15B/C), CC191 (12.2% [n= 33], serotype 7F), CC172 (10.3% [n= 28], serotypes 19A, 23A, 23B), CC433 (4.4% [n= 12], serotype 22F), and CC100 (4.4% [n= 12], serotype 33F). The proportion of isolates nonsusceptible to erythromycin and tetracycline increased after 13-valent PCV use (14% [n= 30] versus 29% [n= 14]; P= 0.010) and (4% [n= 9] versus 22% [n= 11]; P< 0.001), respectively. The genetic diversity also increased after 13-valent PCV use (Simpson's diversity index =0.95 versus 0.91; P= 0.022). |
Epidemiology of invasive group A streptococcal disease in Alaska, 2001 to 2013
Rudolph K , Bruce MG , Bruden D , Zulz T , Reasonover A , Hurlburt D , Hennessy T . J Clin Microbiol 2016 54 (1) 134-41 The Arctic Investigations Program (AIP) began surveillance for invasive group A streptococcal (GAS) infections in Alaska in 2000 as part of the invasive bacterial diseases population-based laboratory surveillance program. Between 2001 and 2013, there were 516 cases of GAS infection reported, for an overall annual incidence of 5.8 cases per 100,000 persons with 56 deaths (case fatality rate, 10.7%). Of the 516 confirmed cases of invasive GAS infection, 422 (82%) had isolates available for laboratory analysis. All isolates were susceptible to penicillin, cefotaxime, and levofloxacin. Resistance to tetracycline, erythromycin, and clindamycin was seen in 11% (n = 8), 5.8% (n = 20), and 1.2% (n = 4) of the isolates, respectively. A total of 51 emm types were identified, of which emm1 (11.1%) was the most prevalent, followed by emm82 (8.8%), emm49 (7.8%), emm12 and emm3 (6.6% each), emm89 (6.2%), emm108 (5.5%), emm28 (4.7%), emm92 (4%), and emm41 (3.8%). The five most common emm types accounted for 41% of isolates. The emm types in the proposed 26-valent and 30-valent vaccines accounted for 56% and 78% of all cases, respectively. GAS remains an important cause of invasive bacterial disease in Alaska. Continued surveillance of GAS infections will help improve understanding of the epidemiology of invasive disease, with an impact on disease control, notification of outbreaks, and vaccine development. |
Antibody levels and protection after hepatitis B vaccine: Results of a 30-year follow-up study and response to a booster dose
Bruce MG , Bruden D , Hurlburt D , Zanis C , Thompson G , Rea L , Toomey M , Townshend-Bulson L , Rudolph K , Bulkow L , Spradling PR , Baum R , Hennessy T , McMahon BJ . J Infect Dis 2016 214 (1) 16-22 BACKGROUND: The duration of protection in children and adults resulting from hepatitis B vaccination is unknown. In 1981, we immunized a cohort of 1578 Alaska Native adults and children from 15 Alaska communities aged ≥6 months using 3 doses of plasma-derived hepatitis B vaccine. METHODS: Persons were tested for antibody to hepatitis B surface antigen (anti-HBs) levels 30 years after receiving the primary series. Those with levels <10 mIU/mL received 1 booster dose of recombinant hepatitis B vaccine 2-4 weeks later and were then evaluated on the basis of anti-HBs measurements 30 days after the booster. RESULTS: Among 243 persons (56%) who responded to the original primary series but received no subsequent doses during the 30-year period, 125 (51%) had an anti-HBs level ≥10 mIU/mL. Among participants with anti-HBs levels <10 mIU/mL who were available for follow-up, 75 of 85 (88%) responded to a booster dose with an anti-HBs level ≥10 mIU/mL at 30 days. Initial anti-HBs level after the primary series was correlated with higher anti-HBs levels at 30 years. CONCLUSIONS: Based on anti-HBs level ≥10 mIU/mL at 30 years and an 88% booster dose response, we estimate that ≥90% of participants had evidence of protection 30 years later. Booster doses are not needed. |
Impact of the 13-valent pneumococcal conjugate vaccine (pcv13) on invasive pneumococcal disease and carriage in Alaska
Bruce MG , Singleton R , Bulkow L , Rudolph K , Zulz T , Gounder P , Hurlburt D , Bruden D , Hennessy T . Vaccine 2015 33 (38) 4813-9 BACKGROUND: Alaska Native (AN) children have experienced high rates of invasive pneumococcal disease (IPD). In March 2010, PCV13 was introduced statewide in Alaska. We evaluated the impact of PCV13 on IPD in children and adults, 45 months after introduction. METHODS: Pneumococcal sterile site isolates, reported through state-wide surveillance, were serotyped using standard methods. We defined a pre-PCV13 time period 2005-2008 and post-PCV13 time period April 2010-December 2013; excluding Jan 2009-March 2010 because PCV13 was introduced pre-licensure in one high-risk region in 2009. RESULTS: Among Alaska children <5 years, PCV13 serotypes comprised 65% of IPD in the pre-PCV13 period and 26% in the PCV13 period. Among all Alaska children <5 years, IPD rates decreased from 60.9 (pre) to 25.4 (post) per 100,000/year (P<0.001); PCV13 serotype IPD decreased from 37.7 to 6.4 (P<0.001). Among AN children <5 years, IPD rates decreased from 149.2 to 60.8 (P<0.001); PCV13 serotype IPD decreased from 87.0 to 17.4 (P<0.001); non-PCV13 serotype IPD did not change significantly. Among persons 5-17 and ≥45 years, the post-vaccine IPD rate was similar to the baseline period, but declined in persons 18-44 years (39%, P<0.001); this decline was similar in AN and non-AN persons (38%, P=0.016, 43%, P=0.014, respectively). CONCLUSIONS: Forty-five months after PCV13 introduction, overall IPD and PCV13-serotype IPD rates had decreased 58% and 83%, respectively, in Alaska children <5 years of age when compared with 2005-2008. We observed evidence of indirect effect among adults with a 39% reduction in IPD among persons 18-44 years. |
Impact of the Pneumococcal Conjugate Vaccine and Antibiotic Use on Nasopharyngeal Colonization by Antibiotic Nonsusceptible Streptococcus pneumoniae, Alaska, 2000-2010
Gounder PP , Brewster M , Bruce MG , Bruden DJ , Rudolph K , Hurlburt DA , Hennessy TW . Pediatr Infect Dis J 2015 34 (11) 1223-9 BACKGROUND: We describe the relative impact of the heptavalent pneumococcal conjugate vaccine (PCV7, introduced 2001) and antibiotic use on colonization by antibiotic resistant pneumococci in urban Alaskan children during 2000-2010. METHODS: We obtained nasopharyngeal swab specimens from a convenience sample of children aged <5 years at clinics annually during 2000-2004 and 2008-2010. PCV7 status and antibiotic use < 90 days before enrollment was determined by interview/medical records review. Pneumococci were characterized by serotype and susceptibility to penicillin (PCN). Isolates with full PCN resistance (PCN-R) or intermediate PCN resistance (PCN-I) were classified as PCN-NS. RESULTS: We recruited 3,496 children (median: 452/year). During 2000-2010, a range of 18-29%/year of children used PCN/amoxicillin (p-value for trend [p] = 0.09); the proportion age-appropriately vaccinated with PCV7 increased (0%-90%; p <0.01). Among pneumococcal isolates, the PCV7-serotype proportion decreased (53%-<1%; p <0.01) and non-PCV7-serotype proportion increased (43%-95%; p <0.01). PCN-R pneumococcal colonizationprevalence decreased (23%-9%, p <0.01) and PCN-I pneumococcal colonization prevalence increased (13%-24%, p <0.01); overall PCN-NS pneumococcalcolonizationprevalence was unchanged. PCN-NS among colonizing PCV7-type and non-PCV7-type pneumococci remained unchanged; a mean of 31%/year of PCV7-type and 10%/year of non-PCV7-type isolates were PCN-R, and 10%/year of PCV7 and 20%/year of non-PCV7-type isolates were PCN-I. CONCLUSIONS: Overall PCN-NS pneumococcal colonization remained unchanged during 2000-2010 because increased colonization by predominantly PCN-I non-PCV7 serotypes offset decreased colonization by predominantly PCN-R PCV7 serotypes. Proportion PCN-NS did not increase within colonizing pneumococcal serotype-groups (PCV7 versus non-PCV7) despite stable penicillin use in our population. |
PCV7-induced changes in pneumococcal carriage and invasive disease burden in Alaskan children
Keck JW , Wenger JD , Bruden DL , Rudolph KM , Hurlburt DA , Hennessy TW , Bruce MG . Vaccine 2014 32 (48) 6478-84 BACKGROUND: Changes in pneumococcal serotype-specific carriage and invasive pneumococcal disease (IPD) after the introduction of pneumococcal conjugate vaccine (PCV7) could inform serotype epidemiology patterns following the introduction of newer conjugate vaccines. METHODS: We used data from statewide IPD surveillance and annual pneumococcal carriage studies in four regions of Alaska to calculate serotype-specific invasiveness ratios (IR; odds ratio of a carried serotype's likelihood to cause invasive disease compared to other serotypes) in children <5 years of age. We describe changes in carriage, disease burden, and invasiveness between two time periods, the pre-PCV7 period (1996-2000) and the late post-PCV7 period (2006-2009). RESULTS: Incidence of IPD decreased from the pre- to post-vaccine period (95.7 vs. 57.2 cases per 100,000 children, P<0.001), with a 99% reduction in PCV7 disease. Carriage prevalence did not change between the two periods (49% vs. 50%), although PCV7 serotype carriage declined by 97%, and non-vaccine serotypes increased in prevalence. Alaska pre-vaccine IRs corresponded to pooled results from eight pre-vaccine comparator studies (Spearman's rho=0.44, P=0.002) and to the Alaska post-vaccine period (Spearman's rho=0.28, P=0.029). Relatively invasive serotypes (IR>1) caused 66% of IPD in both periods, although fewer serotypes with IR>1 remained in the post-vaccine (n=9) than the pre-vaccine period (n=13). CONCLUSIONS: After PCV7 introduction, serotype IRs changed little, and four of the most invasive serotypes were nearly eliminated. If PCV13 use leads to a reduction of carriage and IPD for the 13 vaccine serotypes, the overall IPD rate should further decline. |
Reinfection after successful eradication of Helicobacter pylori in three different populations in Alaska
Bruce MG , Bruden DL , Morris JM , Reasonover AL , Sacco F , Hurlburt D , Hennessy TW , Gove J , Parkinson A , Sahagun G , Davis P , Klejka J , McMahon BJ . Epidemiol Infect 2014 143 (6) 1-11 We performed a study to determine rates of reinfection in three groups followed for 2 years after successful treatment: American Indian/Alaska Native (AI/AN) persons living in urban (group 1) and rural (group 2) communities, and urban Alaska non-Native persons (group 3). We enrolled adults diagnosed with H. pylori infection based on a positive urea breath test (13C-UBT). After successful treatment was documented at 2 months, we tested each patient by 13C-UBT at 4, 6, 12 and 24 months. At each visit, participants were asked about medication use, illnesses and risk factors for reinfection. We followed 229 persons for 2 years or until they became reinfected. H. pylori reinfection occurred in 36 persons; cumulative reinfection rates were 14.5%, 22.1%, and 12.0% for groups 1, 2, and 3, respectively. Study participants who became reinfected were more likely to have peptic ulcer disease (P = 0.02), low education level (P = 0.04), or have a higher proportion of household members infected with H. pylori compared to participants who did not become reinfected (P = 0.03). Among all three groups, reinfection occurred at rates higher than those reported for other US populations (<5% at 2 years); rural AI/AN individuals appear to be at highest risk for reinfection. |
Risk factors for pneumococcal colonization of the nasopharynx in Alaska Native adults and children
Reisman J , Rudolph K , Bruden D , Hurlburt D , Bruce MG , Hennessy T . J Pediatric Infect Dis Soc 2014 3 (2) 104-111 BACKGROUND: Alaska Native children have high invasive pneumococcal disease (IPD) rates, and lack of inhome running water has been shown to have a significant association with infection. Pneumococcal conjugate vaccines reduced IPD; however, this population saw substantial replacement disease and colonization with nonvaccine serotypes. We evaluated risk factors for nasopharyngeal pneumococcal colonization in Alaska Native adults and children. METHODS: We conducted annual surveys from 2008 through 2011 of residents of all ages in 8 rural Alaskan villages. Interviews were conducted, medical charts were reviewed, and nasopharyngeal swabs were cultured for Streptococcus pneumoniae. Multivariate logistic regression models were developed for 3 age groups (under 10 years, 10-17 years, and 18 years and older) to determine risk factors for colonization. RESULTS: We obtained 12 535 nasopharyngeal swabs from 4980 participants. Our population lived in severely crowded conditions, and 48% of households lacked in-home running water. In children <10 years, colonization was associated with lack of in-home running water, household crowding, and more children in the home. Pneumococcal vaccination status was not associated with colonization. In older children and adults, increased number of persons in the household was associated with pneumococcal colonization. CONCLUSIONS: Higher colonization prevalence may partially explain increased IPD rates seen in those lacking in-home water services. Improving availability of sanitation services and reducing household crowding may reduce the burden of IPD in this population. |
Characterizing wild bird contact and seropositivity to highly pathogenic avian influenza A (H5N1) virus in Alaskan residents
Reed C , Bruden D , Byrd KK , Veguilla V , Bruce M , Hurlburt D , Wang D , Holiday C , Hancock K , Ortiz JR , Klejka J , Katz JM , Uyeki TM . Influenza Other Respir Viruses 2014 8 (5) 516-23 BACKGROUND: Highly pathogenic avian influenza A (HPAI) H5N1 viruses have infected poultry and wild birds on three continents with more than 600 reported human cases (59% mortality) since 2003. Wild aquatic birds are the natural reservoir for avian influenza A viruses, and migratory birds have been documented with HPAI H5N1 virus infection. Since 2005, clade 2.2 HPAI H5N1 viruses have spread from Asia to many countries. OBJECTIVES: We conducted a cross-sectional seroepidemiological survey in Anchorage and western Alaska to identify possible behaviors associated with migratory bird exposure and measure seropositivity to HPAI H5N1. METHODS: We enrolled rural subsistence bird hunters and their families, urban sport hunters, wildlife biologists, and a comparison group without bird contact. We interviewed participants regarding their exposures to wild birds and collected blood to perform serologic testing for antibodies against a clade 2.2 HPAI H5N1 virus strain. RESULTS: Hunters and wildlife biologists reported exposures to wild migratory birds that may confer risk of infection with avian influenza A viruses, although none of the 916 participants had evidence of seropositivity to HPAI H5N1. CONCLUSIONS: We characterized wild bird contact among Alaskans and behaviors that may influence risk of infection with avian influenza A viruses. Such knowledge can inform surveillance and risk communication surrounding HPAI H5N1 and other influenza viruses in a population with exposure to wild birds at a crossroads of intercontinental migratory flyways. |
Effect of the 13-valent pneumococcal conjugate vaccine on nasopharyngeal colonization by Streptococcus pneumoniae - Alaska, 2008-2012
Gounder PP , Bruce MG , Bruden DJ , Singleton RJ , Rudolph K , Hurlburt DA , Hennessy TW , Wenger J . J Infect Dis 2014 209 (8) 1251-8 BACKGROUND: In 2010, a 13-valent pneumococcal conjugate vaccine (PCV13) replaced a 7-valent vaccine (PCV7) that contained all PCV7 serotypes plus 6 additional serotypes (PCV6+). We conducted annual surveys from 2008 to 2012 to determine the effect of PCV13 on colonization by pneumococcal serotypes. METHODS: We obtained nasopharyngeal swabs for pneumococcal identification and serotyping from residents of all ages at 8 rural villages and children age <60 months at 2 urban clinics. We conducted interviews/medical records review for all participants. RESULTS: A total of 18 207 nasopharyngeal swabs (rural = 16 098; urban = 2109) were collected. From 2008 to 2012, 84% of rural and 90% of urban children age <5 years were age-appropriately vaccinated with a PCV. Overall pneumococcal colonization prevalence remained stable among rural (66%) and urban (35%) children age <5 years, and adults age ≥18 years (14%). Colonization by PCV6+ serotypes declined significantly among rural children age <5 years, urban children age <5, and adults age ≥18 over the course of the study (25%-5%, 22%-9%, 22%-6%, respectively). CONCLUSIONS: PCV13 was rapidly introduced into the Alaska childhood immunization schedule and reduced colonization by PCV6+ serotypes among children. Unvaccinated adults also experienced comparable reductions in vaccine serotype colonization indicating substantial indirect protection from PCV13. |
Molecular resistance mechanisms of macrolide-resistant invasive Streptococcus pneumoniae isolates from Alaska, 1986 to 2010.
Rudolph K , Bulkow L , Bruce M , Zulz T , Reasonover A , Harker-Jones M , Hurlburt D , Hennessy T . Antimicrob Agents Chemother 2013 57 (11) 5415-22 The rapid emergence of antibiotic-resistant pneumococcal strains has reduced treatment options. The aim of this study was to determine antimicrobial susceptibilities, serotype distributions, and molecular resistance mechanisms among macrolide-resistant invasive pneumococcal isolates in Alaska from 1986 to 2010. We identified cases of invasive pneumococcal disease in Alaska from 1986 to 2010 through statewide population-based laboratory surveillance. All invasive pneumococcal isolates submitted to the Arctic Investigations Program laboratory were confirmed by standard microbiological methods and serotyped by slide agglutination and the Quellung reaction. MICs were determined by the broth microdilution method, and macrolide-resistant genotypes were determined by multiplex PCR. Among 2,923 invasive pneumococcal isolates recovered from 1986 to 2010, 270 (9.2%) were nonsusceptible to erythromycin; 177 (66%) erythromycin-nonsusceptible isolates demonstrated coresistance to penicillin, and 167 (62%) were multidrug resistant. The most frequent serotypes among the macrolide-resistant isolates were serotypes 6B (23.3%), 14 (20.7%), 19A (16.7%), 9V (8.9%), 19F (6.3%), 6A (5.6%), and 23F (4.8%). mef and erm(B) genes were detected in 207 (77%) and 32 (12%) of the isolates, respectively. Nineteen (7%) of the erythromycin-nonsusceptible isolates contained both mef and erm(B) genotypes; 15 were of serotype 19A. There was significant year-to-year variation in the proportion of isolates that were nonsusceptible to erythromycin (P < 0.001). Macrolide resistance among pneumococcal isolates from Alaska is mediated predominantly by mef genes, and this has not changed significantly over time. However, there was a statistically significant increase in the proportion of isolates that possess both erm(B) and mef, primarily due to serotype 19A isolates. |
Haemophilus influenzae serotype a invasive disease, Alaska, USA, 1983-2011
Bruce MG , Zulz T , Debyle C , Singleton R , Hurlburt D , Bruden D , Rudolph K , Hennessy T , Klejka J , Wenger JD . Emerg Infect Dis 2013 19 (6) 932-7 Before introduction of Haemophilus influenzae type b (Hib) vaccines, rates of Hib disease in Alaska's indigenous people were among the highest in the world. Vaccination reduced rates dramatically; however, invasive H. influenzae type a (Hia) disease has emerged. Cases of invasive disease were identified through Alaska statewide surveillance during 1983-2011. Of 866 isolates analyzed for serotype, 32 (4%) were Hia. No Hia disease was identified before 2002; 32 cases occurred during 2002-2011 (p<0.001). Median age of case-patients was 0.7 years; 3 infants died. Incidence of Hia infection (2002-2011) among children <5 years was 5.4/100,000; 27 cases occurred in Alaska Native children (18/100,000) versus 2 cases in non-Native children (0.5/100,000) (risk ratio = 36, p<0.001). From 12/2009 to 12/2011, 15 cases of Hia disease occurred in southwestern Alaska (in children <5 years, rate = 204/100,000). Since introduction of the Hib conjugate vaccine, Hia infection has become a major invasive bacterial disease in Alaska Native children. |
Epidemiology of pneumococcal serotype 6A and 6C among invasive and carriage isolates from Alaska, 1986-2009.
Rudolph K , Bruce M , Bruden D , Zulz T , Wenger J , Reasonover A , Harker-Jones M , Hurlburt D , Hennessy T . Diagn Microbiol Infect Dis 2012 75 (3) 271-6 We investigated serotype 6A/6C invasive pneumococcal disease (IPD) incidence, genetic diversity, and carriage before and after 7-valent pneumococcal conjugate vaccine (PCV7) introduction in Alaska. IPD cases (1986-2009) were identified through population-based laboratory surveillance. Isolates were initially serotyped by conventional methods, and 6C isolates were differentiated from 6A by polymerase chain reaction. Among invasive and carriage isolates initially typed as 6A, 35% and 50% were identified as 6C, respectively. IPD rates caused by serotype 6A or 6C among children <5 years did not change from the pre- to post-PCV7 period (P = 0.71 and P = 0.09, respectively). Multilocus sequence typing of IPD isolates revealed 28 sequence types. The proportion of serotype 6A carriage isolates decreased from 7.4% pre-PCV7 to 1.8% (P < 0.001) during 2008-2009; the proportion of serotype 6C carriage isolates increased from 3.0% to 8.4% (P = 0.004) among children <5 years. Continued surveillance is warranted to monitor changes in serotype distribution and prevalence. |
Diagnostic accuracy of tests for Helicobacter pylori in an Alaska Native population
Bruden DL , Bruce MG , Miernyk KM , Morris J , Hurlburt D , Hennessy TW , Peters H , Sacco F , Parkinson AJ , McMahon BJ . World J Gastroenterol 2011 17 (42) 4682-8 AIM: To evaluate the accuracy of two non-invasive tests in a population of Alaska Native persons. High rates of Helicobacter pylori (H. pylori) infection, H. pylori treatment failure, and gastric cancer in this population necessitate documentation of infection status at multiple time points over a patient's life. METHODS: In 280 patients undergoing endoscopy, H. pylori was diagnosed by culture, histology, rapid urease test, (13)C urea breath test (UBT), and immunoglobulin G antibodies to H. pylori in serum. The performances of (13)C-UBT and antibody test were compared to a gold standard defined by a positive H. pylori test by culture or, in case of a negative culture result, by positive histology and a positive rapid urease test. RESULTS: The sensitivity and specificity of the (13)C-UBT were 93% and 88%, respectively, relative to the gold standard. The antibody test had an equivalent sensitivity of 93% with a reduced specificity of 68%. The false positive results for the antibody test were associated with previous treatment for an H. pylori infection [relative risk (RR) = 2.8]. High levels of antibodies to H. pylori were associated with chronic gastritis and male gender, while high scores in the (13)C-UBT test were associated with older age and with the H. pylori bacteria load on histological examination (RR = 4.4). CONCLUSION: The (13)C-UBT outperformed the antibody test for H. pylori and could be used when a non-invasive test is clinically necessary to document treatment outcome or when monitoring for reinfection. |
Alaska sentinel surveillance study of Helicobacter pylori isolates from Alaska Native persons from 2000 to 2008
Tveit AH , Bruce MG , Bruden DL , Morris J , Reasonover A , Hurlburt DA , Hennessy TW , McMahon B . J Clin Microbiol 2011 49 (10) 3638-43 Helicobacter pylori infection is more common in Alaska Native persons than in the general U.S. population, with seroprevalence to H. pylori approaching 75%. Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among H. pylori isolates. We analyzed H. pylori data from the Centers for Disease Control and Prevention's sentinel surveillance in Alaska from January 2000 to December 2008 to determine the proportion of culture-positive biopsy specimens with antimicrobial resistance from Alaska Native persons undergoing endoscopy. The aim of the present study was to monitor antimicrobial resistance of H. pylori isolates over time and by region in Alaska Native persons. Susceptibility testing of H. pylori isolates to metronidazole, clarithromycin, amoxicillin, and tetracycline was performed using agar dilution. Susceptibility testing for levofloxacin was performed by Etest. Overall, 45% (532/1,181) of persons undergoing upper endoscopy were culture positive for H. pylori. Metronidazole resistance was demonstrated in isolates from 222/531 (42%) persons, clarithromycin resistance in 159/531 (30%) persons, amoxicillin resistance in 10/531 (2%) persons, and levofloxacin resistance in 30/155 (19%) persons; no tetracycline resistance was documented. The prevalence of metronidazole, clarithromycin, and levofloxacin resistance varied by region. Female patients were more likely than male patients to demonstrate metronidazole (P < 0.05) and clarithromycin (P < 0.05) resistance. No substantial change in the proportion of persons with resistant isolates was observed over time. Resistance to metronidazole, clarithromycin, and levofloxacin is more common among H. pylori isolates from Alaska Native persons than those from elsewhere in the United States. |
Characterization of Helicobacter pylori cagA and vacA genotypes among Alaskans and their correlation with clinical disease.
Miernyk K , Morris J , Bruden D , McMahon B , Hurlburt D , Sacco F , Parkinson A , Hennessy T , Bruce M . J Clin Microbiol 2011 49 (9) 3114-21 Helicobacter pylori infection is common in Alaska. The development of severe H. pylori disease is partially determined by the virulence of the infecting strain. Here we present vacA and cagA genotype data for H. pylori strains isolated from Alaskans and their correlation with clinical disease. We enrolled patients scheduled for esophagogastroduodenoscopy and positive for H. pylori infection. Gastric biopsy specimens from the stomach antrum and fundus were cultured. We performed PCR analysis of the H. pylori vacA gene and for the presence of the cagA gene and cagA empty site. We genotyped 515 H. pylori samples from 220 Native and 66 non-Native Alaskans. We detected the cagA gene in 242/286 (85%) persons; of 222 strains that could be subtyped, 95% (212) were non-Asian cagA and 3% (6) were East Asian cagA. After removing mixed infections (n = 17), 83% of H. pylori strains had either the vacA s1m1 (120/269) or s2m2 (103/269) genotype. Sixty-six percent (68/103) of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. Infection with an H. pylori strain having the cagA gene or vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with a decreased risk of esophagitis (P = 0.003 and 0.0003, respectively). Infection with an H. pylori strain having the vacA s1m1 genotype (compared with s1m2 and s2m2) was associated with an increased risk of peptic ulcer disease (PUD) (P = 0.003). The majority of H. pylori strains in this study carried the non-Asian cagA gene and either the vacA s1m1 or s2m2 genotype. A majority of H. pylori strains with the vacA s2m2 genotype also contained the cagA gene. There was an association of H. pylori genotype with esophagitis and PUD. |
2009 pandemic influenza A H1N1 in Alaska: temporal and geographic characteristics of spread and increased risk of hospitalization among Alaska Native and Asian/Pacific Islander people
Wenger JD , Castrodale LJ , Bruden DL , Keck JW , Zulz T , Bruce MG , Fearey DA , McLaughlin J , Hurlburt D , Hummel KB , Kitka S , Bentley S , Thomas TK , Singleton R , Redd JT , Layne L , Cheek JE , Hennessy TW . Clin Infect Dis 2011 52 S189-S197 Alaska Native people have suffered disproportionately from previous influenza pandemics. We evaluated 3 separate syndromic data sources to determine temporal and geographic patterns of spread of 2009 pandemic influenza A H1N1 (pH1N1) in Alaska, and reviewed records from persons hospitalized with pH1N1 disease in 3 areas in Alaska to characterize clinical and epidemiologic features of disease in Alaskans. A wave of pH1N1 disease swept through Alaska beginning in most areas in August or early September. In rural regions, where Alaska Native people comprise a substantial proportion of the population, disease occurred earlier than in other regions. Alaska Native people and Asian/Pacific Islanders (A/PI) were 2-4 times more likely to be hospitalized than whites. Alaska Native people and other minorities remain at high risk for early and substantial morbidity from pandemic influenza episodes. These findings should be integrated into plans for distribution and use of vaccine and antiviral agents. |
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