Introduction to United States Department of Agriculture VetNet: Status of<i>Salmonella</i>and<i>Campylobacter</i>Databases from 2004 Through 2005

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Salmonella is an important cause of foodborne illness; however, identifying the source of these infections can be difficult. This is especially true for Salmonella serotype Typhimurium which is found in diverse agricultural niches. Extended spectrum cephalosporins (ESC) are one of the primary treatment choices for complicated Salmonella infections. In Salmonella, ESC resistance in the U.S. is mainly mediated by blaCMY genes carried on various plasmids. In this study, we examined whether the characterization of blaCMY plasmids, along with additional information, can help us identify potential sources of infection by Salmonella, and use serotype Typhimurium as a model. In the U.S., monitoring of retail meat, food animals, and ill persons for antimicrobial resistant Salmonella is conducted by the National Antimicrobial Resistance Monitoring System (NARMS). In 2008, 70 isolates (70/581;12.0 %) (34 isolates from retail meat, 23 food animal, and 13 human) were resistant to ceftriaxone and amoxicillin/clavulanic acid. All were PCR-positive for blaCMY and 59/70 (84.3%) of these genes were plasmid-encoded. PCR-based replicon typing (PBRT) identified 42/59 (71.2%) IncI1-blaCMY plasmids and 17/59 (28.8%) IncA/C-blaCMY plasmids. Isolates from chickens or chicken products with blaCMY plasmids primarily had IncI1-blaCMY plasmids (37/40; 92.5%), while all isolates from cattle had IncA/C-blaCMY plasmids. Isolates from humans had either IncA/C- blaCMY (n = 8/12; [66.7%]) or IncI1- blaCMY (n = 4/12 [33.3%]) plasmids. All of the IncI1-blaCMY plasmids were ST12 or were closely related to ST12. Antimicrobial susceptibility patterns (AST) and pulsed-field gel electrophoresis (PFGE) patterns of the isolates were also compared and differences were identified between isolate sources. When the source of a Typhimurium outbreak or sporadic illness is unknown, characterizing outbreak isolate’s blaCMY plasmids, AST, and PFGE patterns may help identify it.

Section: Methodsmentioning

confidence: 99%

Characterization ofbla_CMYPlasmids and Their Possible Role in Source Attribution ofSalmonella entericaSerotype Typhimurium Infections

Folster

Tolar

Pecic

et al. 2014

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“…Two enzyme (XbaI and BlnI) PFGE was performed according to the CDC PulseNet protocol and all PFGE profiles generated were submitted to the PulseNet national database administered by CDC (NARMS-FDA and NARMS-CDC) or USDA VetNet (NARMS-USDA) (Ribot, Fair et al 2006;Jackson, Fedorka-Cray et al 2007). Gel images were captured using the GelDoc XR system (Bio-Rad Laboratories) and Quantity one 1-D analysis software (Bio-Rad Laboratories).…”

Section: Pulsed-field Gel Electrophoresis (Pfge)mentioning

confidence: 99%

Characterization of Extended-Spectrum Cephalosporin–Resistant Salmonella enterica Serovar Heidelberg Isolated from Food Animals, Retail Meat, and Humans in the United States 2009

Pecic

Singh

et al. 2012

Salmonella enterica is one of the most common causes of foodborne illness in the United States. Although salmonellosis is usually self-limiting, severe infections typically require antimicrobial treatment and ceftriaxone, an extended-spectrum cephalosporin, is commonly used in both adults and children. Surveillance conducted by the National Antimicrobial Resistance Monitoring System (NARMS) has shown a recent increase in extended-spectrum cephalosporin (ESC) resistance among Salmonella Heidelberg isolated from food animals at slaughter, retail meat, and humans. ESC resistance among Salmonella in the United States is usually mediated by a plasmidencoded bla CMY β-lactamase. In 2009, we identified 47 ESC resistant bla CMY -positive Heidelberg isolates from humans (n=18), food animals at slaughter (n=16), and retail meats (n=13) associated with a spike in the prevalence of this serovar. Almost 90% (26/29) of the animal and meat isolates were isolated from chicken carcasses or retail chicken meat. We screened NARMS isolates for the presence of bla CMY , determined whether the gene was plasmid-encoded, examined pulsed-field gel electrophoresis patterns to assess the genetic diversities of the isolates, and categorized the bla CMY plasmids by plasmid incompatibility groups and plasmid multi-locus sequence typing. All 47 bla CMY genes were found to be plasmid encoded. Incompatibility/replicon typing demonstrated that 41 were IncI1 plasmids, 40 of which only conferred bla CMY associated resistance. Six were IncA/C plasmids that carried additional resistance genes. Plasmid multi-locus sequence typing (pMLST) of the IncI1-bla CMY plasmids showed that 27 (65.8%) were sequence type (ST) 12, the most common ST among bla CMY -IncI1 plasmids from Heidelberg isolated from humans. Ten plasmids had a new ST profile, ST66, a type very similar to ST12. This work showed that the 2009 increase in ESC resistance among Salmonella Heidelberg was caused mainly by the *

“…1. PFGE has been demonstrated to be one of the most credible and best molecular epidemiological tools for foodborne pathogens (Fisher and Threlfall, 2005;Ribot et al, 2006;Jackson et al, 2007). In an attempt to improve the regional surveillance system, PulseNet Asia Pacific has begun to standardize and share PFGE data through their network (Swaminathan et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Clustering Analysis ofSalmonella entericaSerovar Typhi Isolates in Korea by PFGE, Ribotyping, and Phage Typing

Kim

Park

et al. 2009

Salmonella enterica serovar Typhi is a Gram-negative bacterium causing the acute febrile disease typhoid fever. In Korea from 2004 to 2006, a total of 51 Salmonella Typhi isolates were identified in stool and blood from healthy carriers and patients with or without overseas travel histories. In this study, antibiogram, pulsed-field gel electrophoresis (PFGE), and automated ribotyping were performed as molecular epidemiological methods with phage typing as a classical subtyping tool of the isolates. Only two isolates were multidrug resistant and 82.3% of the isolates were susceptible to 16 antimicrobial agents tested. When the dendrogram was created based on the PFGE results, the subtypes could be clustered into five groups by 80% similarity criterion. The PFGE patterns of 31 isolates (60.8%) belonged to Cluster 3, the predominant cluster in the study. Three overseas travel-associated cases were differentiated into Cluster 4 of which three isolates were nalidixic acid or multidrug resistant. Major phage type and ribotype were A and PvuII-436-8-S-6, respectively. This study also showed the prevalence of PFGE Cluster 3 in Korea by clustering analysis and the link between some typhoid cases and travel to Cambodia, India, or Indonesia.