Last data update: Jan 27, 2025. (Total: 48650 publications since 2009)
Records 1-8 (of 8 Records) |
Query Trace: Bruden DL[original query] |
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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. |
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. |
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. |
Long-term immunogenicity of inactivated hepatitis A vaccine: follow-up at 15 years
Byrd KK , Bruden DL , Bruce MG , Bulkow LR , Zanis CL , Snowball MM , Homan CE , Hennessy TW , Williams JL , Dunaway E , Chaves SS , McMahon BJ . J Pediatr Infect Dis 2010 5 (4) 321-326 We conducted a 10-15 years follow-up to a long-term prospective cohort study on the immunogenicity of inactivated hepatitis A vaccine in Alaska Native children, who were initially vaccinated between 3-6 years of age. Children received three vaccine doses (320 E.U.) and were randomized into the following vaccination schedules: A (0, 1, 2 months); B (0, 1, 6 months); and C (0, 1, 12 months). Sera were collected every 2 years and tested for hepatitis A virus (anti-HAV). Levels 20 mIU/mL were considered protective. Anti-HAV geometric mean concentrations were compared by vaccination schedule at 10, 12 and 14 years of follow-up, using ANOVA. Antibody decline over the entire 15-year follow-up period was also analyzed. While none of the inter-schedule comparisons differed significantly from each other at the 10, 12 and 14-year periods, schedules B and C had significantly higher anti-HAV levels than schedule A over the entire 15 years of the study (P0.01). All schedule B and C children maintained seroprotective levels in all follow-up periods. Fourteen percent of schedule A children fell below seroprotective levels at 14 years. Our model estimated that anti-HAV geometric mean concentrations would fall below seroprotective levels at 26, 30 and 32 years for schedules A, B and C, respectively. The data indicate that hepatitis A immunity lasts at least 15 years after vaccination in children and that a booster dose is not needed during that time. However, continued monitoring is necessary to assess the need for a booster dose later in the second and third decade after receipt of the primary series. |
Factors associated with the progression of fibrosis on liver biopsy in Alaska Native and American Indian persons with chronic hepatitis C
Livingston SE , Deubner H , Bruden DL , McMahon BJ , Homan CE , Townshend-Bulson LJ , Bruce MG , Hennessy TW , Williams JL , Gretch DR . Can J Gastroenterol 2010 24 (7) 445-51 BACKGROUND: Various factors influence the development and rate of fibrosis progression in chronic hepatitis C virus (HCV) infection. OBJECTIVES: To examine factors associated with fibrosis in a longterm outcomes study of Alaska Native/American Indian persons who underwent liver biopsy, and to examine the rate of fibrosis progression in persons with subsequent biopsies. METHODS: A cross-sectional analysis of the demographic, inflammatory and viral characteristics of persons undergoing liver biopsy compared individuals with early (Ishak fibrosis score of lower than 3) with those with advanced (Ishak score of 3 or greater) fibrosis. Persons who underwent two or more biopsies were analyzed for factors associated with fibrosis progression. RESULTS: Of 253 HCV RNA-positive persons who underwent at least one liver biopsy, 76 (30%) had advanced fibrosis. On multivariate analysis, a Knodell histological activity index score of 10 to 14 and an alpha-fetoprotein level of 8 ng/mL or higher were found to be independent predictors of advanced liver fibrosis (P<0.0001 for each). When surrogate markers of liver inflammation (alanine aminotransferase, aspartate aminotransferase/alanine aminotransferase ratio and alpha-fetoprotein) were removed from the model, type 2 diabetes mellitus (P=0.001), steatosis (P=0.03) and duration of HCV infection by 10-year intervals (P=0.02) were associated with advanced fibrosis. Among 52 persons who underwent two or more biopsies a mean of 6.2 years apart, the mean Ishak fibrosis score increased between biopsies (P=0.002), with progression associated with older age at initial biopsy and HCV risk factors. CONCLUSIONS: The presence of type 2 diabetes mellitus, steatosis and duration of HCV infection were independent predictors of advanced fibrosis in the present cohort, with significant fibrosis progression demonstrated in persons who underwent serial biopsies. |
Methicillin-resistant staphylococcus aureus-associated hospitalizations among the American Indian and Alaska Native population
Byrd KK , Holman RC , Bruce MG , Hennessy TW , Wenger JD , Bruden DL , Haberling DL , Steiner C , Cheek JE . Clin Infect Dis 2009 49 (7) 1009-15 BACKGROUND: American Indians and Alaska Natives (AI/ANs) have had documented outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) infection but, to our knowledge, no studies have examined MRSA infection among this population nationally. We describe MRSA-associated hospitalizations among the approximately 1.6 million AI/ANs who receive care at Indian Health Service health care facilities nationwide. METHODS: We used hospital discharge data from the Indian Health Service National Patient Information Reporting System to determine the rate of MRSA-associated hospitalizations among AI/ANs who used Indian Health Service health care in 1996-2005 and in the comparison periods 1996-1998 and 2003-2005. Hospitalization rates among AI/ANs were examined by year, age group, sex, and region. MRSA-associated diagnoses were also examined. Rate comparisons were performed using Poisson regression analysis. Comparison of rates to those of the general United States population was made for 2003-2005 by means of the Nationwide Inpatient Sample. RESULTS: Between comparison periods, the rate of MRSA-associated hospitalization increased from 4.6 to 50.6 hospitalizations per 100,000 AI/ANs ([Formula: see text]), with increases in both sexes, all age groups, and all regions. By 2005, MRSA was the causative organism for the majority (52%) of all S. aureus-associated hospitalizations. The most common associated diagnosis was skin and soft-tissue infection, which accounted for 59% of MRSA-associated diagnoses. In 2003-2005, the age-adjusted rate among AI/ANs was 58.8 hospitalizations per 100,000 persons, compared with 84.7 hospitalizations per 100,000 persons in the general US population. CONCLUSIONS: MRSA-associated hospitalizations have increased significantly among AI/ANs served by Indian Health Service health care facilities. Clinicians should have a high index of suspicion for MRSA infection in AI/ANs, especially in those with a diagnosis of skin and soft-tissue infection. |
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