Last data update: Apr 29, 2024. (Total: 46658 publications since 2009)
Records 1-15 (of 15 Records) |
Query Trace: Pecic G[original query] |
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Changing plasmid types responsible for extended-spectrum cephalosporin resistance in Escherichia coli O157:H7 in the USA, 1996-2009
Folster JP , Pecic G , Stroika S , Rickert R , Whichard JM . J Glob Antimicrob Resist 2014 2 (2) 87-91 Escherichia coli O157 is a major cause of food-borne illness. Plasmids are genetic elements that mobilise antimicrobial resistance determinants, including blaCMY beta-lactamases that confer resistance to extended-spectrum cephalosporins (ESCs). ESCs are important for treating a variety of infections. IncA/C plasmids are found among diverse sources, including cattle, the principal source of E. coli O157 infections in humans. IncI1 plasmids are common among E. coli and Salmonella from poultry and other avian sources. To broaden our understanding of the reservoirs of blaCMY, the types of plasmids carrying blaCMY among E. coli O157 were determined. From 1996 to 2009, 3742 E. coli O157 isolates were tested. Eleven isolates (0.29%) were ceftriaxone-resistant and had a blaCMY-2-containing plasmid. All four isolates submitted before 2001 as well as a single 2001 isolate had bla CMY encoded on IncA/C plasmids, whilst all five isolates submitted after 2001 and a single 2001 isolate had blaCMY carried on IncI1 plasmids. The IncI1 plasmids were ST2, ST20 and ST23. We conclude that cephalosporin resistance among E. coli O157:H7 is due to plasmid-encoded blaCMY genes and that plasmid types appear to have shifted from IncA/C to IncI1. This shift suggests either a change in plasmid type among animal reservoirs or that the organism has expanded into avian reservoirs. More analysis of human, retail meat and food animal isolates is necessary to broaden our understanding of the antimicrobial resistance determinants of ESC resistance among E. coli O157. |
Clinical outcomes of nalidixic acid, ceftriaxone, and multidrug-resistant nontyphoidal Salmonella infections compared with pansusceptible infections in FoodNet Sites, 2006-2008
Krueger AL , Greene SA , Barzilay EJ , Henao O , Vugia D , Hanna S , Meyer S , Smith K , Pecic G , Hoefer D , Griffin PM . Foodborne Pathog Dis 2014 11 (5) 335-41 BACKGROUND: Nontyphoidal Salmonella causes an estimated 1.2 million infections, 23,000 hospitalizations, and 450 deaths annually in the United States. Most illnesses are self-limited; however, treatment with antimicrobial agents can be life-saving for invasive infections. METHODS: The Foodborne Diseases Active Surveillance Network and the National Antimicrobial Resistance Monitoring System collaborated on a prospective cohort study of patients with nontyphoidal Salmonella bloodstream and gastrointestinal infections to determine differences in the clinical outcomes of resistant compared with pansusceptible infections. Interviews were conducted within 85 days of specimen collection date. RESULTS: Of 875 nontyphoidal Salmonella isolates, 705 (81%) were pansusceptible, 165 (19%) were resistant to at least 1 agent, and 5 (0.6%) had only intermediate resistance. The most common pattern, found in 51 (31%) of resistant isolates, was resistance to at least ampicillin, chloramphenicol, streptomycin, sulfisoxazole, and tetracycline (ACSSuT); 88% of isolates with this pattern were serotype Typhimurium or Newport. Fourteen (52%) of the 27 ceftriaxone-resistant isolates were also ACSSuT resistant. Adjusted for age and serotype, bloodstream infection was significantly more common among patients infected with strains resistant to only two, only three, or only five antimicrobial classes, to ACSSuT with or without other agents, to ACSSuT only, or to nalidixic acid with or without other agents than among patients with pansusceptible isolates. Adjusted for age, serotype, and bloodstream infection, hospitalization was significantly more common among patients infected with strains resistant to only three agents or to ceftriaxone (all ceftriaxone-resistant isolates were resistant to other agents) than among patients with pansusceptible isolates. CONCLUSION: This study extends evidence that patients with antimicrobial-resistant nontyphoidal Salmonella infections have more severe outcomes. Prevention efforts are needed to reduce unnecessary antimicrobial use in patient care settings and in food animals to help prevent the emergence of resistance and infections with resistant nontyphoidal Salmonella. |
Characterization of blaCMY plasmids and their possible role in source attribution of Salmonella enterica serotype typhimurium infections
Folster JP , Tolar B , Pecic G , Sheehan D , Rickert R , Hise K , Zhao S , Fedorka-Cray PJ , McDermott P , Whichard JM . Foodborne Pathog Dis 2014 11 (4) 301-6 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 United States 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 used serotype Typhimurium as a model. In the United States, monitoring of retail meat, food animals, and ill persons for antimicrobial-resistant Salmonella is conducted by the National Antimicrobial Resistance Monitoring System. 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 polymerase chain reaction (PCR)-positive for blaCMY and 59/70 (84.3%) of these genes were plasmid encoded. PCR-based replicon typing 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 the outbreak isolate's blaCMY plasmids, AST, and PFGE patterns may help identify it. |
Antimicrobial resistance genes in multidrug-resistant Salmonella enterica isolated from animals, retail meats, and humans in the United States and Canada.
Glenn LM , Lindsey RL , Folster JP , Pecic G , Boerlin P , Gilmour MW , Harbottle H , Zhao S , McDermott PF , Fedorka-Cray PJ , Frye JG . Microb Drug Resist 2013 19 (3) 175-84 Salmonella enterica is a prevalent foodborne pathogen that can carry multidrug resistance (MDR) and pose a threat to human health. Identifying the genetics associated with MDR in Salmonella isolated from animals, foods, and humans can help determine sources of MDR in food animals and their impact on humans. S. enterica serovars most frequently carrying MDR from healthy animals, retail meats, and human infections in the United States and Canada were identified and isolates resistant to the largest number of antimicrobials were chosen. Isolates were from U.S. slaughter (n=12), retail (9), and humans (9), and Canadian slaughter (9), retail (9), and humans (8; total n=56). These isolates were assayed by microarray for antimicrobial resistance and MDR plasmid genes. Genes detected encoded resistance to aminoglycosides (alleles of aac, aad, aph, strA/B); beta-lactams (blaTEM, blaCMY, blaPSE-1); chloramphenicol (cat, flo, cmlA); sulfamethoxazole (sulI); tetracycline (tet(A, B, C, D) and tetR); and trimethoprim (dfrA). Hybridization with IncA/C plasmid gene probes indicated that 27/56 isolates carried one of these plasmids; however, they differed in several variable regions. Cluster analysis based on genes detected separated most of the isolates into two groups, one with IncA/C plasmids and one without IncA/C plasmids. Other plasmid replicons were detected in all but one isolate, and included I1 (25/56), N (23/56), and FIB (10/56). The presence of different mobile elements along with similar resistance genes suggest that these genetic elements may acquire similar resistance cassettes, and serve as multiple sources for MDR in Salmonella from food animals, retail meats, and human infections. |
Characterization of extended-spectrum cephalosporin-resistant Salmonella enterica serovar Heidelberg isolated from food animals, retail meat, and humans in the United States 2009
Folster JP , Pecic G , Singh A , Duval B , Rickert R , Ayers S , Abbott J , McGlinchey B , Bauer-Turpin J , Haro J , Hise K , Zhao S , Fedorka-Cray PJ , Whichard J , McDermott PF . Foodborne Pathog Dis 2012 9 (7) 638-45 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 (ESC), is commonly used in both adults and children. Surveillance conducted by the National Antimicrobial Resistance Monitoring System (NARMS) has shown a recent increase in 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 plasmid-encoded bla(CMY) beta-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 (pMLST). 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. 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 dissemination of bla(CMY) on IncI1 and IncA/C plasmids in a variety of genetic backgrounds, and is likely not the result of clonal expansion. |
Characterization of multi-drug resistant Salmonella enterica serovar Heidelberg from a ground turkey-associated outbreak in the United States, 2011
Folster JP , Pecic G , Rickert R , Taylor J , Zhao S , Fedorka-Cray PL , Whichard J , McDermott P . Antimicrob Agents Chemother 2012 56 (6) 3465-6 Salmonella serotype Heidelberg is the fifth most common serotype that causes human disease in the United States and appears to be more invasive than other nontyphoidal serotypes (3, 6).... |
Characterization of isolates from a multi-drug resistant outbreak of Shiga toxin-producing Escherichia coli O145 infections in the United States
Folster JP , Pecic G , Taylor E , Whichard J . Antimicrob Agents Chemother 2011 55 (12) 5955-6 Shiga toxin-producing Escherichia coli (STEC) is an important cause of foodborne illness and several outbreaks of non-O157 serotype infections have been reported recently (10, 17).... |
Characterization of bla(CMY)-encoding plasmids among Salmonella isolated in the United States in 2007
Folster JP , Pecic G , McCullough A , Rickert R , Whichard JM . Foodborne Pathog Dis 2011 8 (12) 1289-94 Salmonella enterica is one of the most common bacterial causes of foodborne illness, and nontyphoidal Salmonella is estimated to cause approximately 1.2 million illnesses in the United States each year. Plasmids are mobile genetic elements that play a critical role in the dissemination of antimicrobial resistance determinants. AmpC-type CMY beta-lactamases (bla(CMY)) confer resistance to extended-spectrum cephalosporins and beta-lactam/beta-lactamase inhibitor combinations and are commonly plasmid-encoded. A variety of plasmids have been shown to encode CMY beta-lactamases and certain plasmids may be associated with particular Salmonella serotypes or environmental sources. In this study, we characterized bla(CMY) beta-lactamase-encoding plasmids among Salmonella isolates. Isolates of Salmonella from specimens collected from humans in 2007 were submitted to the Centers for Disease Control and Prevention National Antimicrobial Resistance Monitoring System laboratory for susceptibility testing. Three percent (65/2161) of Salmonella isolates displayed resistance to ceftriaxone (minimum inhibitory concentration [MIC] ≥4 mg/L) and amoxicillin/clavulanic acid (MIC ≥32 mg/L), a combination associated with the presence of a bla(CMY) mechanism of resistance. Sixty-four (98.5%) isolates were polymerase chain reaction-positive for bla(CMY) genes. Transformation and conjugation studies showed that 95% (61/64) of the bla(CMY) genes were plasmid-encoded. Most of the bla(CMY)-positive isolates were serotype Typhimurium, Newport, Heidelberg, and Agona. Forty-three plasmids were replicon type IncA/C, 15 IncI1, 2 contained multiple replicon loci, and 1 was untypeable. IncI1 plasmids conferred only the bla(CMY)-associated resistance phenotype, whereas IncA/C plasmids conferred additional multi-drug resistance (MDR) phenotypes to drugs such as chloramphenicol, sulfisoxazole, and tetracycline. Most of the IncI1 plasmids (12/15) were sequence type 12 by plasmid multi-locus sequence typing. CMY beta-lactamase-encoding plasmids among human isolates of Salmonella in the United States tended to be large MDR IncA/C plasmids or single resistance determinant IncI1 plasmids. In general, IncI1 plasmids were identified among serotypes commonly associated with poultry, whereas IncA/C plasmids were more likely to be identified among cattle/beef-associated serotypes. |
Ciprofloxacin-resistant Salmonella enterica serotype Typhi, United States, 1999-2008
Medalla F , Sjolund-Karlsson M , Shin SH , Harvey E , Joyce K , Theobald L , Nygren BL , Pecic G , Gay K , Austin J , Stuart A , Blanton E , Mintz ED , Whichard JM , Barzilay EJ . Emerg Infect Dis 2011 17 (6) 1095-1098 We report 9 ciprofloxacin-resistant Salmonella enterica serotype Typhi isolates submitted to the US National Antimicrobial Resistance Monitoring System during 1999-2008. The first 2 had indistinguishable pulsed-field gel electrophoresis patterns and identical gyrA and parC mutations. Eight of the 9 patients had traveled to India within 30 days before illness onset. |
Decreased susceptibility to ciprofloxacin among Shigella isolated in the United States 2006-2009
Folster JP , Pecic G , Bowen A , Rickert R , Carattoli A , Whichard JM . Antimicrob Agents Chemother 2011 55 (4) 1758-60 We characterized 20 Shigella isolates with decreased susceptibility to fluoroquinolones. Most patients (80%) from whom a travel history was obtained reported travel to South or Southeast Asia. Mutations within the quinolone resistance determining regions of gyrA and parC and plasmid-mediated resistance determinants (qnrB, qnrS, aac(6')-Ib-cr) were identified. The rise in antimicrobial resistance among Shigella may necessitate the increased use of extended-spectrum cephalosporins or macrolides in some patients. |
CTX-M-producing non-Typhi Salmonella spp. isolated from humans, United States
Sjolund-Karlsson M , Howie R , Krueger A , Rickert R , Pecic G , Lupoli K , Folster JP , Whichard JM . Emerg Infect Dis 2011 17 (1) 97-9 CTX-M-type Beta-lactamases are increasing among US Enterobacteriaceae isolates. Of 2,165 non-Typhi Salmonella isolates submitted in 2007 to the National Antimicrobial Resistance Monitoring System, 100 (4.6%) displayed elevated MICs (≥2 mg/L) of ceftriaxone or ceftiofur. Three isolates (serotypes Typhimurium, Concord, and I 4,5,12:i:-) contained blaCTX-M-5, blaCTX-M-15, and blaCTX-M-55/57, respectively. |
Salmonella isolates with decreased susceptibility to extended-spectrum cephalosporins in the United States
Sjolund-Karlsson M , Rickert R , Matar C , Pecic G , Howie RL , Joyce K , Medalla F , Barzilay EJ , Whichard JM . Foodborne Pathog Dis 2010 7 (12) 1503-9 OBJECTIVE: We describe the antimicrobial susceptibility to extended-spectrum cephalosporins in non-Typhi Salmonella (NTS) isolated from humans in the United States and explore resistance mechanisms for isolates displaying decreased susceptibility to ceftriaxone or ceftiofur. We further explore the concordance between the newly revised Clinical and Laboratory Standards Institute (CLSI) breakpoints for ceftriaxone and the presence of a beta-lactamase. METHODS: In 2005 and 2006, public health laboratories in all U.S. state health departments forwarded every 20th NTS isolate from humans to Centers for Disease Control and Prevention as part of the National Antimicrobial Resistance Monitoring System (NARMS) for enteric bacteria. Minimum inhibitory concentrations (MICs) were determined by broth microdilution. Isolates displaying decreased susceptibility (MIC ≥ 2 mg/L) to ceftriaxone or ceftiofur were included in the study. The presence of beta-lactamase genes was investigated by polymerase chain reaction amplification and sequencing, targeting six different genes (bla(TEM), bla(OXA), bla(SHV), bla(CTX-M), bla(PSE), and bla(CMY)). Plasmid location of bla(CMY) was confirmed by transforming plasmids into Escherichia coli. RESULTS: Among the 4236 isolates of NTS submitted to NARMS in 2005 and 2006, 175 (4.1%) displayed decreased susceptibility to either ceftriaxone or ceftiofur. By polymerase chain reaction screening, one or more beta-lactamase genes could be detected in 139 (80.8%) isolates. The most prevalent resistance mechanism detected was the AmpC beta-lactamase gene bla(CMY.) Other beta-lactamase genes detected included 11 bla(TEM-1), 3 bla(PSE-1), 2 bla(OXA-1), and 1 bla(CTX-M-15). The ceftriaxone MIC values for the bla(CMY)-containing isolates ranged from 4 to 64 mg/L; all bla(CMY)-bearing isolates were classified as ceftriaxone resistant according to current CLSI guidelines. CONCLUSIONS: Among NTS isolates submitted to NARMS in 2005 and 2006, cephamycinase beta-lactamases are the predominant cause of decreased susceptibility to ceftriaxone. The fact that all bla(CMY)-containing isolates were classified as resistant to ceftriaxone (MIC ≥ 4 mg/L) supports the newly revised CLSI breakpoints for cephalosporins and Enterobacteriaceae. |
Plasmid-mediated quinolone resistance among non-Typhi Salmonella enterica isolates, USA
Sjolund-Karlsson M , Howie R , Rickert R , Krueger A , Tran TT , Zhao S , Ball T , Haro J , Pecic G , Joyce K , Fedorka-Cray PJ , Whichard JM , McDermott PF . Emerg Infect Dis 2010 16 (11) 1789-91 We determined the prevalence of plasmid-mediated quinolone resistance mechanisms among non-Typhi Salmonella spp. isolated from humans, food animals, and retail meat in the United States in 2007. Six isolates collected from humans harbored aac(6')Ib-cr or a qnr gene. Most prevalent was qnrS1. No animal or retail meat isolates harbored a plasmid-mediated mechanism. |
Identification and characterization of CTX-M-producing Shigella isolates in the United States
Folster JP , Pecic G , Krueger A , Rickert R , Burger K , Carattoli A , Whichard JM . Antimicrob Agents Chemother 2010 54 (5) 2269-70 Shigellosis is a major source of gastroenteritis throughout the world (14). ... |
Characterization of extended-spectrum cephalosporin-resistant salmonella enterica serovar heidelberg isolated from humans in the United States
Folster JP , Pecic G , Bolcen S , Theobald L , Hise K , Carattoli A , Zhao S , McDermott PF , Whichard JM . Foodborne Pathog Dis 2009 7 (2) 181-7 During the past decade, extended-spectrum cephalosporin resistance has increased among human isolates of Salmonella enterica serovar Heidelberg, the fourth most common serotype in the United States. We therefore characterized 54 Heidelberg isolates with decreased susceptibility (minimum inhibitory concentrations ≥2 mg/L) to ceftriaxone or ceftiofur; 49 (90.7%) contained the CMY-type beta-lactamase (bla(CMY)) gene. The 49 bla(CMY)-positive human Heidelberg isolates demonstrated a high degree of relatedness; 4 clusters (25 isolates total) had indistinguishable XbaI and BlnI patterns by pulsed-field gel electrophoresis and were indistinguishable from 42 retail meat Heidelberg isolates. Further characterization of 15 of these isolates demonstrated that all of the bla genes were bla(CMY-2) and plasmid-encoded, and most (11/15) of the plasmids were approximately 100 kb in size and belong to the incompatibility group I1 (IncI1). All five IncI1 plasmids tested by plasmid multilocus sequence typing analysis were ST12. This report suggests that extended-spectrum cephalosporin resistance among human Heidelberg isolates is mediated by the spread of a common IncI1 bla(CMY-2) plasmid, which may have a preference for a particular genetic background. |
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