Last data update: Nov 04, 2024. (Total: 48056 publications since 2009)
Records 1-30 (of 33 Records) |
Query Trace: Chen JC[original query] |
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Multistate nontyphoidal Salmonella and Shiga toxin-producing Escherichia coli outbreaks linked to international travel - United States, 2017-2020
Habrun CA , Birhane MG , François Watkins LK , Benedict K , Bottichio L , Nemechek K , Tolar B , Schroeder MN , Chen JC , Caidi H , Robyn M , Nichols M . Epidemiol Infect 2024 1-33 Enteric bacterial infections are common among people who travel internationally. During 2017– | 23 2020, CDC investigated 41 multistate outbreaks of nontyphoidal Salmonella and Shiga toxin24 producing Escherichia coli (STEC) linked to international travel. Resistance to one or more | 25 antimicrobial agents was detected in at least 10% of isolates in 16 of 30 (53%) nontyphoidal | 26 Salmonella outbreaks and 8 of 11 (73%) STEC outbreaks evaluated by the National | 27 Antimicrobial Resistance Monitoring System. At least 10% of the isolates in 14 nontyphoidal | 28 Salmonella outbreaks conferred resistance to one or more of the clinically significant | 29 antimicrobials used in human medicine. This report describes the epidemiology and | 30 antimicrobial resistance patterns of these travel-associated multistate outbreaks. Investigating | 31 illnesses among returned travelers and collaboration with international partners could result in | 32 implementation of public health interventions to improve hygiene practices and food safety | 33 standards, and to prevent illness and spread of multidrug resistant organisms domestically and | 34 internationally |
Antimicrobial resistance in multistate outbreaks of nontyphoidal Salmonella infections linked to animal contact-United States, 2015-2018
Frey E , Stapleton GS , Nichols MC , Gollarza LM , Birhane M , Chen JC , McCullough A , Carleton HA , Trees E , Hise KB , Tolar B , Francois Watkins L . J Clin Microbiol 2023 e0098123 Animal contact is an established risk factor for nontyphoidal Salmonella infections and outbreaks. During 2015-2018, the U.S. Centers for Disease Control and Prevention (CDC) and other U.S. public health laboratories began implementing whole-genome sequencing (WGS) of Salmonella isolates. WGS was used to supplement the traditional methods of pulsed-field gel electrophoresis for isolate subtyping, outbreak detection, and antimicrobial susceptibility testing (AST) for the detection of resistance. We characterized the epidemiology and antimicrobial resistance (AMR) of multistate salmonellosis outbreaks linked to animal contact during this time period. An isolate was considered resistant if AST yielded a resistant (or intermediate, for ciprofloxacin) interpretation to any antimicrobial tested by the CDC or if WGS showed a resistance determinant in its genome for one of these agents. We identified 31 outbreaks linked to contact with poultry (n = 23), reptiles (n = 6), dairy calves (n = 1), and guinea pigs (n = 1). Of the 26 outbreaks with resistance data available, we identified antimicrobial resistance in at least one isolate from 20 outbreaks (77%). Of 1,309 isolates with resistance information, 247 (19%) were resistant to ≥1 antimicrobial, and 134 (10%) were multidrug-resistant to antimicrobials from ≥3 antimicrobial classes. The use of resistance data predicted from WGS increased the number of isolates with resistance information available fivefold compared with AST, and 28 of 43 total resistance patterns were identified exclusively by WGS; concordance was high (>99%) for resistance determined by AST and WGS. The use of predicted resistance from WGS enhanced the characterization of the resistance profiles of outbreaks linked to animal contact by providing resistance information for more isolates. |
Evaluation of whole and core genome multilocus sequence typing allele schemes for Salmonella enterica outbreak detection in a national surveillance network, PulseNet USA
Leeper MM , Tolar BM , Griswold T , Vidyaprakash E , Hise KB , Williams GM , Im SB , Chen JC , Pouseele H , Carleton HA . Front Microbiol 2023 14 1254777 Salmonella enterica is a leading cause of bacterial foodborne and zoonotic illnesses in the United States. For this study, we applied four different whole genome sequencing (WGS)-based subtyping methods: high quality single-nucleotide polymorphism (hqSNP) analysis, whole genome multilocus sequence typing using either all loci [wgMLST (all loci)] and only chromosome-associated loci [wgMLST (chrom)], and core genome multilocus sequence typing (cgMLST) to a dataset of isolate sequences from 9 well-characterized Salmonella outbreaks. For each outbreak, we evaluated the genomic and epidemiologic concordance between hqSNP and allele-based methods. We first compared pairwise genomic differences using all four methods. We observed discrepancies in allele difference ranges when using wgMLST (all loci), likely caused by inflated genetic variation due to loci found on plasmids and/or other mobile genetic elements in the accessory genome. Therefore, we excluded wgMLST (all loci) results from any further comparisons in the study. Then, we created linear regression models and phylogenetic tanglegrams using the remaining three methods. K-means analysis using the silhouette method was applied to compare the ability of the three methods to partition outbreak and sporadic isolate sequences. Our results showed that pairwise hqSNP differences had high concordance with cgMLST and wgMLST (chrom) allele differences. The slopes of the regressions for hqSNP vs. allele pairwise differences were 0.58 (cgMLST) and 0.74 [wgMLST (chrom)], and the slope of the regression was 0.77 for cgMLST vs. wgMLST (chrom) pairwise differences. Tanglegrams showed high clustering concordance between methods using two statistical measures, the Baker's gamma index (BGI) and cophenetic correlation coefficient (CCC), where 9/9 (100%) of outbreaks yielded BGI values ≥ 0.60 and CCCs were ≥ 0.97 across all nine outbreaks and all three methods. K-means analysis showed separation of outbreak and sporadic isolate groups with average silhouette widths ≥ 0.87 for outbreak groups and ≥ 0.16 for sporadic groups. This study demonstrates that Salmonella isolates clustered in concordance with epidemiologic data using three WGS-based subtyping methods and supports using cgMLST as the primary method for national surveillance of Salmonella outbreak clusters. |
Reoccurring Escherichia coli O157:H7 strain linked to leafy greens-associated outbreaks, 2016-2019
Chen JC , Patel K , Smith PA , Vidyaprakash E , Snyder C , Tagg KA , Webb HE , Schroeder MN , Katz LS , Rowe LA , Howard D , Griswold T , Lindsey RL , Carleton HA . Emerg Infect Dis 2023 29 (9) 1895-1899 Genomic characterization of an Escherichia coli O157:H7 strain linked to leafy greens-associated outbreaks dates its emergence to late 2015. One clade has notable accessory genomic content and a previously described mutation putatively associated with increased arsenic tolerance. This strain is a reoccurring, emerging, or persistent strain causing illness over an extended period. |
Novel quinolone resistance determinant, qepA8, in Shigella flexneri isolated in the United States, 2016 (preprint)
Webb HE , Tagg KA , Chen JC , Kim J , Lindsey R , Francois Watkins LK , Karp BE , Sugawara Y , Folster JP . bioRxiv 2019 726950 A qepA8+ Shigella flexneri was cultured from the stool of a traveler returning from India and East Asia. This chromosomally encoded qepA variant, has a six-base insertion, and may have been mobilized as part of a complex IS1-mediated composite transposon including catA1, aadA1, and blaOXA-1. In laboratory E. coli, qepA8 alone only conferred decreased ciprofloxacin susceptibility; however, it may work in combination with additional mechanisms to confer clinical resistance. |
Erratum: Vol. 71, No. 6.
Lambrou AS , Shirk P , Steele MK , Paul P , Paden CR , Cadwell B , Reese HE , Aoki Y , Hassell N , Caravas J , Kovacs NA , Gerhart JG , Ng HJ , Zheng XY , Beck A , Chau R , Cintron R , Cook PW , Gulvik CA , Howard D , Jang Y , Knipe K , Lacek KA , Moser KA , Paskey AC , Rambo-Martin BL , Nagilla RR , Rethchless AC , Schmerer MW , Seby S , Shephard SS , Stanton RA , Stark TJ , Uehara A , Unoarumhi Y , Bentz ML , Burhgin A , Burroughs M , Davis ML , Keller MW , Keong LM , Le SS , Lee JS , Madden Jr JC , Nobles S , Owouor DC , Padilla J , Sheth M , Wilson MM , Talarico S , Chen JC , Oberste MS , Batra D , McMullan LK , Halpin AL , Galloway SE , MacCannell DR , Kondor R , Barnes J , MacNeil A , Silk BJ , Dugan VG , Scobie HM , Wentworth DE . MMWR Morb Mortal Wkly Rep 2022 71 (14) 528 The report “Genomic Surveillance for SARS-CoV-2 Variants: Predominance of the Delta (B.1.617.2) and Omicron (B.1.1.529) Variants — United States, June 2021–January 2022” contained several errors. |
SneakerNet: A modular quality assurance and quality check workflow for primary genomic and metagenomic read data.
Griswold T , Kapsak C , Chen JC , den Bakker HC , Williams G , Kelley A , Vidyaprakash E , Katz LS . J Open Source Softw 2021 6 (60) Laboratories that run Whole Genome Sequencing (WGS) produce a tremendous amount of data, up to 10 gigabytes for some common instruments. There is a need to standardize the quality assurance and quality control process (QA/QC). Therefore we have created SneakerNet to automate the QA/QC for WGS. |
Increased Multidrug-Resistant Salmonella enterica I Serotype 4,[5],12:i:- Infections Associated with Pork, United States, 2009-2018.
Plumb ID , Brown AC , Stokes EK , Chen JC , Carleton H , Tolar B , Sundararaman P , Saupe A , Payne DC , Shah HJ , Folster JP , Friedman CR . Emerg Infect Dis 2023 29 (2) 314-22 Reports of Salmonella enterica I serotype 4,[5],12:i:- infections resistant to ampicillin, streptomycin, sulphamethoxazole, and tetracycline (ASSuT) have been increasing. We analyzed data from 5 national surveillance systems to describe the epidemiology, resistance traits, and genetics of infections with this Salmonella strain in the United States. We found ASSuT-resistant Salmonella 4,[5],12:i:- increased from 1.1% of Salmonella infections during 2009-2013 to 2.6% during 2014-2018; the proportion of Salmonella 4,[5],12:i:- isolates without this resistance pattern declined from 3.1% to 2.4% during the same timeframe. Among isolates sequenced during 2015-2018, a total of 69% were in the same phylogenetic clade. Within that clade, 77% of isolates had genetic determinants of ASSuT resistance, and 16% had genetic determinants of decreased susceptibility to ciprofloxacin, ceftriaxone, or azithromycin. Among outbreaks related to the multidrug-resistant clade, 63% were associated with pork consumption or contact with swine. Preventing Salmonella 4,[5],12:i:- carriage in swine would likely avert human infections with this strain. |
Molecular characterization of circulating Salmonella Typhi strains in an urban informal settlement in Kenya.
Ochieng C , Chen JC , Osita MP , Katz LS , Griswold T , Omballa V , Ng'eno E , Ouma A , Wamola N , Opiyo C , Achieng L , Munywoki PK , Hendriksen RS , Freeman M , Mikoleit M , Juma B , Bigogo G , Mintz E , Verani JR , Hunsperger E , Carleton HA . PLoS Negl Trop Dis 2022 16 (8) e0010704 A high burden of Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) bacteremia has been reported from urban informal settlements in sub-Saharan Africa, yet little is known about the introduction of these strains to the region. Understanding regional differences in the predominant strains of S. Typhi can provide insight into the genomic epidemiology. We genetically characterized 310 S. Typhi isolates from typhoid fever surveillance conducted over a 12-year period (2007-2019) in Kibera, an urban informal settlement in Nairobi, Kenya, to assess the circulating strains, their antimicrobial resistance attributes, and how they relate to global S. Typhi isolates. Whole genome multi-locus sequence typing (wgMLST) identified 4 clades, with up to 303 pairwise allelic differences. The identified genotypes correlated with wgMLST clades. The predominant clade contained 290 (93.5%) isolates with a median of 14 allele differences (range 0-52) and consisted entirely of genotypes 4.3.1.1 and 4.3.1.2. Resistance determinants were identified exclusively in the predominant clade. Determinants associated with resistance to aminoglycosides were observed in 245 isolates (79.0%), sulphonamide in 243 isolates (78.4%), trimethoprim in 247 isolates (79.7%), tetracycline in 224 isolates (72.3%), chloramphenicol in 247 isolates (79.6%), β-lactams in 239 isolates (77.1%) and quinolones in 62 isolates (20.0%). Multidrug resistance (MDR) determinants (defined as determinants conferring resistance to ampicillin, chloramphenicol and cotrimoxazole) were found in 235 (75.8%) isolates. The prevalence of MDR associated genes was similar throughout the study period (2007-2012: 203, 76.3% vs 2013-2019: 32, 72.7%; Fisher's Exact Test: P = 0.5478, while the proportion of isolates harboring quinolone resistance determinants increased (2007-2012: 42, 15.8% and 2013-2019: 20, 45.5%; Fisher's Exact Test: P<0.0001) following a decline in S. Typhi in Kibera. Some isolates (49, 15.8%) harbored both MDR and quinolone resistance determinants. There were no determinants associated with resistance to cephalosporins or azithromycin detected among the isolates sequenced in this study. Plasmid markers were only identified in the main clade including IncHI1A and IncHI1B(R27) in 226 (72.9%) isolates, and IncQ1 in 238 (76.8%) isolates. Molecular clock analysis of global typhoid isolates and isolates from Kibera suggests that genotype 4.3.1 has been introduced multiple times in Kibera. Several genomes from Kibera formed a clade with genomes from Kenya, Malawi, South Africa, and Tanzania. The most recent common ancestor (MRCA) for these isolates was from around 1997. Another isolate from Kibera grouped with several isolates from Uganda, sharing a common ancestor from around 2009. In summary, S. Typhi in Kibera belong to four wgMLST clades one of which is frequently associated with MDR genes and this poses a challenge in treatment and control. |
Genomic Diversity, Antimicrobial Resistance, and Virulence Gene Profiles of Salmonella Serovar Kentucky Isolated from Humans, Food, and Animal Ceca Content Sources in the United States.
Tate H , Hsu CH , Chen JC , Han J , Foley SL , Folster JP , Francois Watkins LK , Reynolds J , Tillman GE , Nyirabahizi E , Zhao S . Foodborne Pathog Dis 2022 19 (8) 509-521 Salmonella serovar Kentucky is frequently isolated from chickens and dairy cattle, but recovery from humans is comparatively low based on the U.S. National Antimicrobial Resistance Monitoring System (NARMS) reports. We aimed to better describe the genetic diversity, antimicrobial resistance, and virulence determinants of Salmonella Kentucky isolates from humans, food animal ceca, retail meat and poultry products, imported foods and food products, and other samples. We analyzed the genomes of 774 Salmonella Kentucky isolates and found that 63% (54/86) of human isolates were sequence type (ST)198, 33% (29/86) were ST152, and 3.5% (3/86) were ST314. Ninety-one percent (570/629) of cecal isolates and retail meat and poultry isolates were ST152 or ST152-like (one allele difference), and 9.2% (58/629) were ST198. Isolates from imported food were mostly ST198 (60%, 22/37) and ST314 (29.7%, 11/37). ST198 isolates clustered into two main lineages. Clade ST198.2 comprised almost entirely isolates from humans and imported foods, all containing triple mutations in the quinolone resistance-determining region (QRDR) that confer resistance to fluoroquinolones. Clade ST198.1 contained isolates from humans, ceca, retail meat and poultry products, and imported foods that largely lacked QRDR mutations. ST152 isolates from cattle had a lineage (Clade 2) distinct from ST152 isolates from chicken (Clade 4), and half of ST152 human isolates clustered within two other clades (Clades 1 and 3), largely distinct from Clades 2 and 4. Although clinical illness associated with Salmonella Kentucky is low, ST198 appears to account for most human infections in the Unites States but is uncommon among ceca of domestic food animals and retail meat and poultry products. These findings, combined with human exposure data, suggest that fluoroquinolone-resistant ST198 infections may be linked to the consumption of food products that are imported or consumed while traveling. We also found unique differences in the composition of virulence genes and antimicrobial resistance genes among the clades, which may provide clues to the host specificity and pathogenicity of Salmonella Kentucky lineages. |
Genomic Surveillance for SARS-CoV-2 Variants: Predominance of the Delta (B.1.617.2) and Omicron (B.1.1.529) Variants - United States, June 2021-January 2022.
Lambrou AS , Shirk P , Steele MK , Paul P , Paden CR , Cadwell B , Reese HE , Aoki Y , Hassell N , Caravas J , Kovacs NA , Gerhart JG , Ng HJ , Zheng XY , Beck A , Chau R , Cintron R , Cook PW , Gulvik CA , Howard D , Jang Y , Knipe K , Lacek KA , Moser KA , Paskey AC , Rambo-Martin BL , Nagilla RR , Rethchless AC , Schmerer MW , Seby S , Shephard SS , Stanton RA , Stark TJ , Uehara A , Unoarumhi Y , Bentz ML , Burhgin A , Burroughs M , Davis ML , Keller MW , Keong LM , Le SS , Lee JS , Madden Jr JC , Nobles S , Owouor DC , Padilla J , Sheth M , Wilson MM , Talarico S , Chen JC , Oberste MS , Batra D , McMullan LK , Halpin AL , Galloway SE , MacCannell DR , Kondor R , Barnes J , MacNeil A , Silk BJ , Dugan VG , Scobie HM , Wentworth DE . MMWR Morb Mortal Wkly Rep 2022 71 (6) 206-211 Genomic surveillance is a critical tool for tracking emerging variants of SARS-CoV-2 (the virus that causes COVID-19), which can exhibit characteristics that potentially affect public health and clinical interventions, including increased transmissibility, illness severity, and capacity for immune escape. During June 2021-January 2022, CDC expanded genomic surveillance data sources to incorporate sequence data from public repositories to produce weighted estimates of variant proportions at the jurisdiction level and refined analytic methods to enhance the timeliness and accuracy of national and regional variant proportion estimates. These changes also allowed for more comprehensive variant proportion estimation at the jurisdictional level (i.e., U.S. state, district, territory, and freely associated state). The data in this report are a summary of findings of recent proportions of circulating variants that are updated weekly on CDC's COVID Data Tracker website to enable timely public health action.(†) The SARS-CoV-2 Delta (B.1.617.2 and AY sublineages) variant rose from 1% to >50% of viral lineages circulating nationally during 8 weeks, from May 1-June 26, 2021. Delta-associated infections remained predominant until being rapidly overtaken by infections associated with the Omicron (B.1.1.529 and BA sublineages) variant in December 2021, when Omicron increased from 1% to >50% of circulating viral lineages during a 2-week period. As of the week ending January 22, 2022, Omicron was estimated to account for 99.2% (95% CI = 99.0%-99.5%) of SARS-CoV-2 infections nationwide, and Delta for 0.7% (95% CI = 0.5%-1.0%). The dynamic landscape of SARS-CoV-2 variants in 2021, including Delta- and Omicron-driven resurgences of SARS-CoV-2 transmission across the United States, underscores the importance of robust genomic surveillance efforts to inform public health planning and practice. |
Outbreak of Multidrug-Resistant Salmonella Heidelberg Infections Linked to Dairy Calf Exposure, United States, 2015-2018.
Nichols M , Gollarza L , Sockett D , Aulik N , Patton E , Francois Watkins LK , Gambino-Shirley KJ , Folster JP , Chen JC , Tagg KA , Stapleton GS , Trees E , Ellison Z , Lombard J , Morningstar-Shaw B , Schlater L , Elbadawi L , Klos R . Foodborne Pathog Dis 2022 19 (3) 199-208 In August 2016, the Wisconsin Department of Health Services notified the U.S. Centers for Disease Control and Prevention of multidrug-resistant (MDR) Salmonella enterica serovar Heidelberg infections in people who reported contact with dairy calves. Federal and state partners investigated this to identify the source and scope of the outbreak and to prevent further illnesses. Cases were defined as human Salmonella Heidelberg infection caused by a strain that had one of seven pulsed-field gel electrophoresis (PFGE) patterns or was related by whole genome sequencing (WGS), with illness onset from January 1, 2015, through July 2, 2018. Patient exposure and calf purchase information was collected and analyzed; calves were traced back from the point of purchase. Isolates obtained from animal and environmental samples collected on-farm were supplied by veterinary diagnostic laboratories and compared with patient isolates using PFGE and WGS. Antimicrobial susceptibility testing by standardized broth microdilution was performed. Sixty-eight patients from 17 states were identified. Forty (63%) of 64 patients noted cattle contact before illness. Thirteen (33%) of 40 patients with exposure to calves reported that calves were sick or had died. Seven individuals purchased calves from a single Wisconsin livestock market. One hundred forty cattle from 14 states were infected with the outbreak strain. WGS indicated that human, cattle, and environmental isolates from the livestock market were genetically closely related. Most isolates (88%) had resistance or reduced susceptibility to antibiotics of ≥5 antibiotic classes. This resistance profile included first-line antibiotic treatments for patients with severe salmonellosis, including ampicillin, ceftriaxone, and ciprofloxacin. In this outbreak, MDR Salmonella Heidelberg likely spread from sick calves to humans, emphasizing the importance of illness surveillance in animal populations to prevent future spillover of this zoonotic disease. |
Ongoing Outbreak of Extensively Drug-Resistant Campylobacter jejuni Infections Associated With US Pet Store Puppies, 2016-2020.
Francois Watkins LK , Laughlin ME , Joseph LA , Chen JC , Nichols M , Basler C , Breazu R , Bennett C , Koski L , Montgomery MP , Hughes MJ , Robertson S , Lane CG , Singh AJ , Stanek D , Salehi E , Brandt E , McGillivary G , Mowery J , DeMent J , Aubert RD , Geissler AL , de Fijter S , Williams IT , Friedman CR . JAMA Netw Open 2021 4 (9) e2125203 IMPORTANCE: Extensively drug-resistant Campylobacter jejuni infections cannot be treated with any commonly recommended antibiotics and pose an increasing public health threat. OBJECTIVES: To investigate cases of extensively drug-resistant C jejuni associated with pet store puppies and describe the epidemiologic and laboratory characteristics of these infections. DESIGN, SETTING, AND PARTICIPANTS: In August 2017, health officials identified, via survey, patients with C jejuni infections who reported contact with puppies sold by pet stores. In conjunction with state and federal partners, the Centers for Disease Control and Prevention investigated cases of culture-confirmed C jejuni infections in US patients with an epidemiologic or molecular association with pet store puppies between January 1, 2016, and February 29, 2020. Available records from cases occurring before 2016 with genetically related isolates were also obtained. MAIN OUTCOMES AND MEASURES: Patients were interviewed about demographic characteristics, health outcomes, and dog exposure during the 7 days before illness onset. Core genome multilocus sequence typing was used to assess isolate relatedness, and genomes were screened for resistance determinants to predict antibiotic resistance. Isolates resistant to fluoroquinolones, macrolides, and 3 or more additional antibiotic classes were considered to be extensively drug resistant. Cases before 2016 were identified by screening all sequenced isolates submitted for surveillance using core genome multilocus sequence typing. RESULTS: A total of 168 patients (median [interquartile range] age, 37 [19.5-51.0] years; 105 of 163 female [64%]) with an epidemiologic or molecular association with pet store puppies were studied. A total of 137 cases occurred from January 1, 2016, to February 29, 2020, with 31 additional cases dating back to 2011. Overall, 117 of 121 patients (97%) reported contact with a dog in the week before symptom onset, of whom 69 of 78 (88%) with additional information reported contact with a pet store puppy; 168 isolates (88%) were extensively drug resistant. Traceback investigation did not implicate any particular breeder, transporter, distributer, store, or chain. CONCLUSIONS AND RELEVANCE: Strains of extensively drug-resistant C jejuni have been circulating since at least 2011 and are associated with illness among pet store customers, employees, and others who come into contact with pet store puppies. The results of this study suggest that practitioners should ask about puppy exposure when treating patients with Campylobacter infection, especially when they do not improve with routine antibiotics, and that the commercial dog industry should take action to help prevent the spread of extensively drug-resistant C jejuni from pet store puppies to people. |
Azithromycin and Ciprofloxacin Treatment Outcomes During an Outbreak of Multidrug-Resistant Shigella sonnei Infections in a Retirement Community-Vermont, 2018.
Gharpure R , Friedman CR , Fialkowski V , Collins JP , Strysko J , Marsh ZA , Chen JC , Meservey EH , Adediran AA , Schroeder MN , Wadhwa A , Fullerton KE , Watkins LF . Clin Infect Dis 2021 74 (3) 455-460 BACKGROUND: In 2018, CDC and the Vermont Department of Health investigated an outbreak of multidrug-resistant Shigella sonnei infections in a retirement community that offered a continuum of care from independent living through skilled nursing care. The investigation identified 24 culture-confirmed cases. Isolates were resistant to trimethoprim-sulfamethoxazole, ampicillin, and ceftriaxone, and had decreased susceptibility to azithromycin and ciprofloxacin. METHODS: To evaluate clinical and microbiologic response, we reviewed inpatient and outpatient medical records for treatment outcomes among the 24 patients with culture-confirmed S. sonnei infection. We defined clinical failure as diarrhea (≥3 loose stools per day) for ≥1 day after treatment finished, and microbiologic failure as a stool culture that yielded S. sonnei after treatment finished. We used broth microdilution to perform antimicrobial susceptibility testing, and whole genome sequencing to identify resistance mechanisms. RESULTS: Isolates contained macrolide resistance genes mph(A) and erm(B) and had azithromycin minimum inhibitory concentrations above the Clinical and Laboratory Standards Institute epidemiological cutoff value of ≤16 µg/mL. Among 24 patients with culture-confirmed Shigella infection, four were treated with azithromycin; all had clinical treatment failure and two also had microbiologic treatment failure. Isolates were susceptible to ciprofloxacin but contained a gyrA mutation; two patients failed treatment with ciprofloxacin. CONCLUSIONS: These azithromycin treatment failures demonstrate the importance of clinical breakpoints to aid clinicians in identifying alternative treatment options for resistant strains. Additionally, these treatment failures highlight a need for comprehensive susceptibility testing and systematic outcome studies, particularly given the emergence of multidrug-resistant Shigella among an expanding range of patient populations. |
Whole-Genome Sequencing Reveals the Presence of the blaCTX-M-65 Gene in Extended-Spectrum β-Lactamase-Producing and Multi-Drug-Resistant Clones of Salmonella Serovar Infantis Isolated from Broiler Chicken Environments in the Galapagos Islands
Burnett E , Ishida M , de Janon S , Naushad S , Duceppe MO , Gao R , Jardim A , Chen JC , Tagg KA , Ogunremi D , Vinueza-Burgos C . Antibiotics (Basel) 2021 10 (3) 1-13 Salmonella Infantis, a common contaminant of poultry products, is known to harbor mobile genetic elements that confer multi-drug resistance (MDR) and have been detected in many continents. Here, we report four MDR S. Infantis strains recovered from poultry house environments in Santa Cruz Island of the Galapagos showing extended-spectrum β-lactamase (ESBL) resistance and reduced fluoroquinolone susceptibility. Whole-genome sequencing (WGS) revealed the presence of the ESBL-conferring blaCTX-M-65 gene in an IncFIB-like plasmid in three S. Infantis isolates. Multi-locus sequence typing (MLST) and single nucleotide variant/polymorphism (SNP) SNVPhyl analysis showed that the S. Infantis isolates belong to sequence type ST32, likely share a common ancestor, and are closely related (1–3 SNP difference) to blaCTX-M-65-containing clinical and veterinary S. Infantis isolates from the United States and Latin America. Furthermore, phylogenetic analysis of SNPs following core-genome alignment (i.e., ParSNP) inferred close relatedness between the S. Infantis isolates from Galapagos and the United States. Prophage typing confirmed the close relationship among the Galapagos S. Infantis and was useful in distinguishing them from the United States isolates. This is the first report of MDR blaCTX-M-65-containing S. Infantis in the Galapagos Islands and highlights the need for increased monitoring and surveillance programs to determine prevalence, sources, and reservoirs of MDR pathogens. |
Carriage and Gene Content Variability of the pESI-Like Plasmid Associated with Salmonella Infantis Recently Established in United States Poultry Production.
McMillan EA , Wasilenko JL , Tagg KA , Chen JC , Simmons M , Gupta SK , Tillman GE , Folster J , Jackson CR , Frye JG . Genes (Basel) 2020 11 (12) Salmonella Infantis carrying extended spectrum β-lactamase bla(CTX-M-65) on a pESI-like megaplasmid has recently emerged in United States poultry. In order to determine the carriage rate and gene content variability of this plasmid in U.S. Salmonella Infantis, whole genome sequences of Salmonella isolates from humans and animals in the U.S. and internationally containing the pESI-like plasmid were analyzed. The U.S. Department of Agriculture Food Safety and Inspection Service (FSIS) identified 654 product sampling isolates containing pESI-like plasmids through hazard analysis and critical control point (HACCP) verification testing in 2017 and 2018. The Centers for Disease Control and Prevention identified 55 isolates with pESI-like plasmids in 2016-2018 through the National Antimicrobial Resistance Monitoring System. Approximately 49% of pESI-like plasmids from FSIS verification isolates and 71% from CDC NARMS contained bla(CTX-M-65). Pan-plasmid genome analysis was also performed. All plasmids contained traN and more than 95% contained 172 other conserved genes; 61% contained bla(CTX-M-65). In a hierarchical clustering analysis, some plasmids from U.S. animal sources clustered together and some plasmids from South America clustered together, possibly indicating multiple plasmid lineages. However, most plasmids contained similar genes regardless of origin. Carriage of the pESI-like plasmid in U.S. appears to be limited to Salmonella Infantis and carriage rates increased from 2017 to 2018. |
Multidrug-resistant Salmonella serotype Anatum in travelers and seafood from Asia, United States
Karp BE , Leeper MM , Chen JC , Tagg KA , Francois Watkins LK , Friedman CR . Emerg Infect Dis 2020 26 (5) 1030-1033 A multidrug-resistant Salmonella enterica serotype Anatum strain reported in Taiwan was isolated in the United States from patients and from seafood imported from Asia. Isolates harbored 11 resistance determinants, including quinolone and inducible cephalosporin resistance genes. Most patients had traveled to Asia. These findings underscore the need for global One Health resistance surveillance. |
Update on Extensively Drug-Resistant Salmonella Serotype Typhi Infections Among Travelers to or from Pakistan and Report of Ceftriaxone-Resistant Salmonella Serotype Typhi Infections Among Travelers to Iraq - United States, 2018-2019.
Francois Watkins LK , Winstead A , Appiah GD , Friedman CR , Medalla F , Hughes MJ , Birhane MG , Schneider ZD , Marcenac P , Hanna SS , Godbole G , Walblay KA , Wiggington AE , Leeper M , Meservey EH , Tagg KA , Chen JC , Abubakar A , Lami F , Asaad AM , Sabaratnam V , Ikram A , Angelo KM , Walker A , Mintz E . MMWR Morb Mortal Wkly Rep 2020 69 (20) 618-622 Ceftriaxone-resistant Salmonella enterica serotype Typhi (Typhi), the bacterium that causes typhoid fever, is a growing public health threat. Extensively drug-resistant (XDR) Typhi is resistant to ceftriaxone and other antibiotics used for treatment, including ampicillin, chloramphenicol, ciprofloxacin, and trimethoprim-sulfamethoxazole (1). In March 2018, CDC began enhanced surveillance for ceftriaxone-resistant Typhi in response to an ongoing outbreak of XDR typhoid fever in Pakistan. CDC had previously reported the first five cases of XDR Typhi in the United States among patients who had spent time in Pakistan (2). These illnesses represented the first cases of ceftriaxone-resistant Typhi documented in the United States (3). This report provides an update on U.S. cases of XDR typhoid fever linked to Pakistan and describes a new, unrelated cluster of ceftriaxone-resistant Typhi infections linked to Iraq. Travelers to areas with endemic Typhi should receive typhoid vaccination before traveling and adhere to safe food and water precautions (4). Treatment of patients with typhoid fever should be guided by antimicrobial susceptibility testing whenever possible (5), and clinicians should consider travel history when selecting empiric therapy. |
Evidence of failure of oral third-generation cephalosporin treatment for Shigella sonnei infection
Collins JP , Friedman CR , Birhane MG , Karp BE , Osinski A , Montgomery MW , Thomas D , Barkley J , Sanchez MC , Hanna S , Adediran AA , Chen JC , Caidi H , Francois Watkins L . Open Forum Infect Dis 2020 7 (4) ofaa113 In 2017, state health departments notified the Centers for Disease Control and Prevention about 4 patients with shigellosis who experienced persistent illness after treatment with oral third-generation cephalosporins. Given increasing antibiotic resistance among Shigella, these cases highlight the need to evaluate the efficacy of oral cephalosporins for shigellosis. |
Sequencing and characterization of five extensively drug-resistant Salmonella enterica serotype Typhi isolates implicated in human infections from Punjab, Pakistan
Tagg KA , Amir A , Ikram A , Chen JC , Kim JY , Meservey E , Joung YJ , Halpin JL , Batra D , Leeper MM , Katz LS , Saeed A , Freeman M , Watkins LF , Salman M , Folster JP . Microbiol Resour Announc 2020 9 (13) A large outbreak of extensively drug-resistant (XDR) Salmonella enterica serotype Typhi infections is ongoing in Pakistan, predominantly in Sindh Province. Here, we report the sequencing and characterization of five XDR Salmonella Typhi isolates from the Punjab province of Pakistan that are closely related to the outbreak strain and carry the same IncY plasmid. |
Novel quinolone resistance determinant, qepA8, in Shigella flexneri isolated in the United States, 2016.
Webb HE , Tagg KA , Chen JC , Kim J , Lindsey R , Francois Watkins LK , Karp BE , Sugawara Y , Folster JP . Antimicrob Agents Chemother 2019 63 (12) Enterobacteriaceae, quinolone resistance is largely attributed to mutations in the quinolone resistance-determining regions (QRDR) of gyrA, gyrB, parC, and parE, and plasmid-italiciated quinolone resistance (PMQR) genes (e.g., qnr genes, aac(6')-Ib-cr, or qepA)..... |
Outbreak of Salmonella Newport Infections with Decreased Susceptibility to Azithromycin Linked to Beef Obtained in the United States and Soft Cheese Obtained in Mexico - United States, 2018-2019.
Plumb ID , Schwensohn CA , Gieraltowski L , Tecle S , Schneider ZD , Freiman J , Cote A , Noveroske D , Kolsin J , Brandenburg J , Chen JC , Tagg KA , White PB , Shah HJ , Francois Watkins LK , Wise ME , Friedman CR . MMWR Morb Mortal Wkly Rep 2019 68 (33) 713-717 In September 2018, CDC identified Salmonella enterica serotype Newport (Newport) infections that were multidrug resistant (MDR), with decreased susceptibility to azithromycin, a recommended oral treatment agent. Until 2017, decreased susceptibility to azithromycin had occurred in fewer than 0.5% of Salmonella isolates from U.S. residents. This report summarizes the investigation of a multistate MDR Salmonella outbreak conducted by CDC, state and local health departments, and the U.S. Department of Agriculture's Food Safety and Inspection Service. During June 2018-March 2019, 255 cases of infection with the outbreak strain were identified in 32 states; 43% of patients (89 of 206 with information on travel) reported recent travel to Mexico. Infections were linked to consumption of soft cheese obtained in Mexico and beef obtained in the United States. Consumers should avoid eating soft cheese that could be made from unpasteurized milk, regardless of the source of the cheese. When preparing beef, a food thermometer should be used to ensure that appropriate cooking temperatures are reached. When antibiotic treatment is needed for a patient, clinicians should choose antibiotics based on susceptibility testing wherever possible. |
Genome wide characterization of enterotoxigenic Escherichia coli serogroup O6 isolates from multiple outbreaks and sporadic infections from 1975-2016.
Pattabiraman V , Katz LS , Chen JC , McCullough AE , Trees E . PLoS One 2018 13 (12) e0208735 Enterotoxigenic Escherichia coli (ETEC) are an important cause of diarrhea globally, particularly among children under the age of five in developing countries. ETEC O6 is the most common ETEC serogroup, yet the genome wide population structure of isolates of this serogroup is yet to be determined. In this study, we have characterized 40 ETEC O6 isolates collected between 1975-2016 by whole genome sequencing (WGS) and by phenotypic antimicrobial susceptibility testing. To determine the relatedness of isolates, we evaluated two methods-whole genome high-quality single nucleotide polymorphism (whole genome-hqSNP) and core genome SNP analyses using Lyve-SET and Parsnp respectively. All isolates were tested for antimicrobial susceptibility using a panel of 14 antibiotics. ResFinder 2.1 and a custom quinolone resistance determinants workflow were used for resistance determinant detection. VirulenceFinder 1.5 was used for prediction of the virulence genes. Thirty-seven isolates clustered into three major clades (I, II, III) by whole genome-hqSNP and core genome SNP analyses, while three isolates included in the whole genome-hqSNP analysis only did not cluster with clades I-III by both analyses and formed a distantly related outgroup, designated clade IV. Median number of pairwise whole genome-hqSNPs in clonal ETEC O6 outbreaks ranged from 0 to 5. Of the 40 isolates tested for antimicrobial susceptibility, 18 isolates were pansusceptible. Twenty-two isolates were resistant to at least one antibiotic, nine of which were multidrug resistant. Phenotypic antimicrobial resistance (AR) correlated with AR determinants in 22 isolates. Thirty-two isolates harbored both enterotoxin virulence genes while the remaining 8 isolates had only one of the two virulence genes. In summary, whole genome-hqSNP and core genome SNP analyses from this study revealed similar evolutionary relationships and an overall diversity of ETEC O6 isolates independent of time of isolation. Less than 5 pairwise hqSNPs between ETEC O6 isolates is circumstantially indicative of an outbreak cluster. Findings from this study will be a basis for quicker outbreak detection and control by efficient subtyping by WGS. |
CTX-M-65 extended-spectrum beta-lactamase-producing Salmonella enterica serotype infantis, United States
Brown AC , Chen JC , Watkins LKF , Campbell D , Folster JP , Tate H , Wasilenko J , Van Tubbergen C , Friedman CR . Emerg Infect Dis 2018 24 (12) 2284-2291 Extended-spectrum beta-lactamases (ESBLs) confer resistance to clinically important third-generation cephalosporins, which are often used to treat invasive salmonellosis. In the United States, ESBLs are rarely found in Salmonella. However, in 2014, the US Food and Drug Administration found blaCTX-M-65 ESBL-producing Salmonella enterica serotype Infantis in retail chicken meat. The isolate had a rare pulsed-field gel electrophoresis pattern. To clarify the sources and potential effects on human health, we examined isolates with this pattern obtained from human surveillance and associated metadata. Using broth microdilution for antimicrobial susceptibility testing and whole-genome sequencing, we characterized the isolates. Of 34 isolates, 29 carried the blaCTX-M-65 gene with <9 additional resistance genes on 1 plasmid. Of 19 patients with travel information available, 12 (63%) reported recent travel to South America. Genetically, isolates from travelers, nontravelers, and retail chicken meat were similar. Expanded surveillance is needed to determine domestic sources and potentially prevent spread of this ESBL-containing plasmid. |
Multidrug-Resistant Campylobacter jejuni Outbreak Linked to Puppy Exposure - United States, 2016-2018.
Montgomery MP , Robertson S , Koski L , Salehi E , Stevenson LM , Silver R , Sundararaman P , Singh A , Joseph LA , Weisner MB , Brandt E , Prarat M , Bokanyi R , Chen JC , Folster JP , Bennett CT , Francois Watkins LK , Aubert RD , Chu A , Jackson J , Blanton J , Ginn A , Ramadugu K , Stanek D , DeMent J , Cui J , Zhang Y , Basler C , Friedman CR , Geissler AL , Crowe SJ , Dowell N , Dixon S , Whitlock L , Williams I , Jhung MA , Nichols MC , de Fijter S , Laughlin ME . MMWR Morb Mortal Wkly Rep 2018 67 (37) 1032-1035 Campylobacter causes an estimated 1.3 million diarrheal illnesses in the United States annually (1). In August 2017, the Florida Department of Health notified CDC of six Campylobacter jejuni infections linked to company A, a national pet store chain based in Ohio. CDC examined whole-genome sequencing (WGS) data and identified six isolates from company A puppies in Florida that were highly related to an isolate from a company A customer in Ohio. This information prompted a multistate investigation by local and state health and agriculture departments and CDC to identify the outbreak source and prevent additional illness. Health officials from six states visited pet stores to collect puppy fecal samples, antibiotic records, and traceback information. Nationally, 118 persons, including 29 pet store employees, in 18 states were identified with illness onset during January 5, 2016-February 4, 2018. In total, six pet store companies were linked to the outbreak. Outbreak isolates were resistant by antibiotic susceptibility testing to all antibiotics commonly used to treat Campylobacter infections, including macrolides and quinolones. Store record reviews revealed that among 149 investigated puppies, 142 (95%) received one or more courses of antibiotics, raising concern that antibiotic use might have led to development of resistance. Public health authorities issued infection prevention recommendations to affected pet stores and recommendations for testing puppies to veterinarians. This outbreak demonstrates that puppies can be a source of multidrug-resistant Campylobacter infections in humans, warranting a closer look at antimicrobial use in the commercial dog industry. |
Novel trimethoprim resistance gene dfrA34 identified in Salmonella Heidelberg in the USA.
Tagg KA , Francois Watkins L , Moore MD , Bennett C , Joung YJ , Chen JC , Folster JP . J Antimicrob Chemother 2018 74 (1) 38-41 Background: Trimethoprim/sulfamethoxazole is a synthetic antibiotic combination recommended for the treatment of complicated non-typhoidal Salmonella infections in humans. Resistance to trimethoprim/sulfamethoxazole is mediated by the acquisition of mobile genes, requiring both a dfr gene (trimethoprim resistance) and a sul gene (sulfamethoxazole resistance) for a clinical resistance phenotype (MIC >/=4/76 mg/L). In 2017, the CDC investigated a multistate outbreak caused by a Salmonella enterica serotype Heidelberg strain with trimethoprim/sulfamethoxazole resistance, in which sul genes but no known dfr genes were detected. Objectives: To characterize and describe the molecular mechanism of trimethoprim resistance in a Salmonella Heidelberg outbreak isolate. Methods: Illumina sequencing data for one outbreak isolate revealed a 588 bp ORF encoding a putative dfr gene. This gene was cloned into Escherichia coli and resistance to trimethoprim was measured by broth dilution and Etest. Phylogenetic analysis of previously reported dfrA genes was performed using MEGA. Long-read sequencing was conducted to determine the context of the novel dfr gene. Results and conclusions: The novel dfr gene, named dfrA34, conferred trimethoprim resistance (MIC >/=32 mg/L) when cloned into E. coli. Based on predicted amino acid sequences, dfrA34 shares less than 50% identity with other known dfrA genes. The dfrA34 gene is located in a class 1 integron in a multiresistance region of an IncC plasmid, adjacent to a sul gene, thus conferring clinical trimethoprim/sulfamethoxazole resistance. Additionally, dfrA34 is associated with ISCR1, enabling easy transmission between other plasmids and bacterial strains. |
Plasmid-mediated quinolone resistance in human non-typhoidal Salmonella infections: An emerging public health problem in the United States
Karp BE , Campbell D , Chen JC , Folster JP , Friedman CR . Zoonoses Public Health 2018 65 (7) 838-849 Invasive Salmonella infections in adults are commonly treated with fluoroquinolones, a critically important antimicrobial class. Historically, quinolone resistance was the result of chromosomal mutations, but plasmid-mediated quinolone resistance (PMQR) has emerged and is increasingly being reported in Enterobacteriaceae worldwide. PMQR may facilitate the spread of quinolone resistance, lead to higher-level quinolone resistance, and make infections harder to treat. To better understand the epidemiology of PMQR in non-typhoidal Salmonella causing human infections in the United States, we looked at trends in quinolone resistance among isolates submitted to the Centers for Disease Control and Prevention. We reviewed demographic, exposure and outcome information for patients with isolates having a PMQR-associated phenotype during 2008-2014 and tested isolates for quinolone resistance mechanisms. We found that PMQR is emerging among non-typhoidal Salmonella causing human infections in the United States and that international travel, reptile and amphibian exposure, and food are likely sources of human infection. |
Report of erm(B)+ Campylobacter jejuni in the United States
Chen JC , Tagg KA , Joung YJ , Bennett C , Watkins LF , Eikmeier D , Folster JP . Antimicrob Agents Chemother 2018 62 (6) Campylobacter is a leading cause of foodborne illness in the United States, causing an estimated 1.3 million illnesses annually. |
Is Colorectal Cancer A Western Disease? Role of Knowledge and Influence of Misconception on Colorectal Cancer Screening among Chinese and Korean Americans: A Mixed Methods Study
Lu X , Holt Ch L , Chen JC , Le D , Chen J , Kim GY , Li J , Lee S . Asian Pac J Cancer Prev 2016 17 (11) 4885-4892 Background: Chinese and Korean Americans have lower colorectal cancer (CRC) screening rates than other racial/ ethnic groups, which may be explained by a low level of CRC knowledge and a high level of misconceptions. This study explores the role of knowledge in CRC screening among these groups. Methods: Chinese (N=59) and Korean (N=61) Americans older than 50 were recruited from the Washington D.C. Metropolitan area. They completed a detailed survey and participated in focus groups to discuss their knowledge on CRC and CRC screening. Seventeen physicians, community leaders, and patient navigators participated in key informant interviews. Using a mixed methods approach, data were analyzed quantitatively and qualitatively. Results: Participants lacked knowledge about CRC and CRC screening. More than half did not know that screening begins at age 50 and there are several types of tests available. More than 30% thought CRC screening was not necessary if there were no symptoms or there was nothing they could do to prevent CRC. Focus group findings suggested understanding about CRC was limited by an inadequate source of linguistically and culturally relevant health information. For example, many participants considered CRC a western condition mainly caused by unhealthy diet. This led to under-estimations about their susceptibility to CRC. Knowledge was positively associated with self-reported screening. Participants who had higher knowledge scores were more likely to report ever having had a colonoscopy and confidence in ability to have CRC screening. Conclusions: Mixed-methods analysis provides multi-faceted perspectives on CRC knowledge and its influence on screening. Study findings can help inform interventions to increase CRC screening among Chinese and Korean Americans. |
Implementation of Whole Genome Sequencing (WGS) for Identification and Characterization of Shiga Toxin-Producing Escherichia coli (STEC) in the United States.
Lindsey RL , Pouseele H , Chen JC , Strockbine NA , Carleton HA . Front Microbiol 2016 7 766 Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen capable of causing severe disease in humans. Rapid and accurate identification and characterization techniques are essential during outbreak investigations. Current methods for characterization of STEC are expensive and time-consuming. With the advent of rapid and cheap whole genome sequencing (WGS) benchtop sequencers, the potential exists to replace traditional workflows with WGS. The aim of this study was to validate tools to do reference identification and characterization from WGS for STEC in a single workflow within an easy to use commercially available software platform. Publically available serotype, virulence, and antimicrobial resistance databases were downloaded from the Center for Genomic Epidemiology (CGE) (www.genomicepidemiology.org) and integrated into a genotyping plug-in with in silico PCR tools to confirm some of the virulence genes detected from WGS data. Additionally, down sampling experiments on the WGS sequence data were performed to determine a threshold for sequence coverage needed to accurately predict serotype and virulence genes using the established workflow. The serotype database was tested on a total of 228 genomes and correctly predicted from WGS for 96.1% of O serogroups and 96.5% of H serogroups identified by conventional testing techniques. A total of 59 genomes were evaluated to determine the threshold of coverage to detect the different WGS targets, 40 were evaluated for serotype and virulence gene detection and 19 for the stx gene subtypes. For serotype, 95% of the O and 100% of the H serogroups were detected at > 40x and ≥ 30x coverage, respectively. For virulence targets and stx gene subtypes, nearly all genes were detected at > 40x, though some targets were 100% detectable from genomes with coverage ≥20x. The resistance detection tool was 97% concordant with phenotypic testing results. With isolates sequenced to > 40x coverage, the different databases accurately predicted serotype, virulence, and resistance from WGS data, providing a fast and cheaper alternative to conventional typing techniques. |
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