Unique Pulsed-field Gel Electrophoresis Research Articles

Presence of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli in Food-Producing and Companion Animals and Wildlife on Small-Holder Farms of Floreana Island, Galápagos Islands.

Background: Antimicrobial resistance (AR) has led to increasing human and animal morbidity and mortality and negative consequences for the environment. AR among Escherichia coli (EC) is on the rise, with serious concerns about extended-spectrum β-lactamase-producing E. coli (ESBL-EC). In the Galápagos Islands, where antimicrobials are available without a prescription, growing demands for food production can drive antimicrobial use. Food producing animals are at the interface of wildlife and environmental health on the smallest human-inhabited Galápagos Island, Floreana. We sought to determine if ESBL-EC were present in Floreana Island farm animal species and nearby wildlife and the relatedness of ESBL-EC isolates identified. Materials and Methods: During July 4-5, 2022, we visited 8 multispecies farms, representing 75% of food-producing animal production on Floreana, and collected 227 fecal samples from farm animals and wildlife. Each sample was plated on MacConkey agar supplemented with cefotaxime (4 μg/mL). Results: ESBL-EC was isolated from 20 (9%) fecal samples collected from pigs (N = 10), chickens (N = 6), wildlife (N = 3), and dog (N = 1). All ESBL-EC isolates were from samples taken at three (38%) of the eight farms. Fifteen (75%) of the ESBL-EC isolates were from a single farm. All ESBL-EC isolates were multidrug resistant. The most prevalent ESBL genes belonged to the blaCTX-M group. Among the typeable isolates from the farm with the largest proportion of ESBL-EC isolates (N = 14), we observed nine unique pulsed-field gel electrophoresis (PFGE) patterns, with identical patterns present across pig and chicken isolates. PFGE patterns in the three farms with ESBL-EC isolates were different. Conclusions: These results lend support for future routine AR monitoring activities at the livestock-wildlife interface in Galápagos to characterize potential interspecies transmission of AR bacteria and AR genes in this unique protected ecosystem, and the related human, animal, and environmental health impacts, and to formulate interventions to reduce AR spread in this setting.

Epidemiological Analysis of Extended-Spectrum β-Lactamase-Producing Klebsiella pneumoniae Outbreak in a Neonatal Clinic in Poland.

Klebsiella pneumoniae is one of the most common etiological agents isolated from epidemic outbreaks in neonatal wards. We describe how an extended-spectrum β-lactamase-producing K. pneumoniae (ESBL-KP) outbreak in a neonatal ward was extinguished. During the outbreak, which lasted over two months, 26 neonates were tested for K. pneumoniae, and 42 environmental swabs were taken. Drug susceptibility was determined for the isolated strains, and their virulence and phylogenetic similarity were checked. ESBL-KP colonization was confirmed in 18 neonates, and six were also confirmed to be infected. All strains isolated from patients represented one clonal type, K. pneumoniae. One strain isolated from an environmental source was determined to be a unique pulsed-field gel electrophoresis pattern. Gestational age and Apgar score were assessed as statistically significant for neonates with ESBL-KP infection. The epidemiological measures taken have been successful, and no further cases appeared. Immediate tightening of hospital hygiene rules, screening of all hospitalized neonates, and cohorting ESBL-KP-positive patients proved effective in controlling and ending the outbreak. The lack of ESBL-KP in the environment suggests that the outbreak was transmitted by colonized hospital staff. This theory could be confirmed by introducing mandatory screening for medical personnel.

Determining the DNA Fingerprinting Profiles of Salmonella Isolates from Raw Poultry Meats and Human Clinical Samples from the Same Geographic Area Using Pulsed-Field Gel Electrophoresis

Foods of animal origin, such as poultry, eggs, and pork, are recognized sources of Salmonella infections, but determination of the proportion of foodborne infections associated with various food sources has been challenging. In the present study, 141 Salmonella isolates recovered from 1,322 poultry product samples purchased over a 1-year period from retail stores across Seattle, WA were subtyped by pulsed-field gel electrophoresis (PFGE) using restriction enzyme XbaI. The objectives of the study were (i) to analyze the longitudinal distribution of Salmonella PFGE profiles throughout the sampling period and their clonality within and between poultry processing establishments, (ii) to determine the association between PFGE profiles of Salmonella isolates from locally distributed poultry products and those of clinical isolates submitted to the Washington State Department of Health (WA-DOH) laboratories, and (iii) to compare the PFGE profiles of Salmonella isolates from the National Antimicrobial Resistance Monitoring System (NARMS) retail meats program. During the 1-year sampling period, multiple indistinguishable PFGE patterns were found across multiple poultry processing establishments. Twelve of the 30 unique PFGE profiles of Salmonella isolates from locally purchased poultry products were indistinguishable from the PFGE profiles of clinical Salmonella isolates submitted to the WA-DOH. When the PFGE profiles from the poultry samples were compared with those found in the NARMS database, eight indistinguishable PFGE matches were found with isolates recovered from chicken breasts, ground turkey, and ground beef from multiple states. Although this study revealed some association between PFGE profiles from raw poultry products and those of clinical isolates from the same geographical area, these results do not prove that all of those clinical isolates were from infections acquired through consumption or handling of poultry.

Characterization of Extended-Spectrum β-Lactamase-Producing and AmpC β-Lactamase-Producing Enterobacterales Isolated from Companion Animals in Korea.

The emergence of extended-spectrum cephalosporin (ESC)-resistant Gram-negative bacteria is of great concern in both human and veterinary medicine. The aim of this study was to investigate ESC-resistant bacterial isolates from companion animals in South Korea between 2017 and 2019. Isolates with ESC resistance genes, which were identified by PCR, were assessed for genetic relatedness by multi-locus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE). In total, 91 ESC-resistant Escherichia coli, Klebsiella spp., Serratia spp., and Enterobacter cloacae isolates harbored the blaTEM gene. Among other ESC resistance genes, blaCTX-M-15, blaCIT, and blaCTX-M-55 were predominantly detected in E. coli isolates, whereas blaSHV and blaDHA were more frequently detected in Klebsiella pneumoniae isolates. In addition, all blaEBC-positive isolates were classified as E. cloacae. From the MLST results, blaCTX-M-9-carrying ST131, blaCIT-carrying ST405, and blaCTX-M-1-carrying ST3285 strains were dominant among E. coli isolates. ST273 and ST275 strains harboring blaSHV were frequently detected in K. pneumoniae isolates. Various sequence types were obtained in E. cloacae and Klebsiella oxytoca isolates. All isolates demonstrated unique PFGE profiles (<57–98% similarity) and were unlikely to be derived from a single clone. The present study reveals the presence and wide genetic distribution of ESC-resistant bacterial species in South Korean companion animals.

Molecular Epidemiology and Drug Resistance Pattern of Carbapenem-Resistant Klebsiella pneumoniae Isolates from Iran.

The emergence and dissemination of carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates and their involvement in several nosocomial outbreaks are of high concern. This study was conducted to investigate the genetic relatedness and molecular determinants of carbapenem resistance in 100 CRKP isolates. Susceptibility to carbapenems as well as other antibiotics was determined by using disk diffusion method. The Modified Hodge test was performed for detection of carbapenemase production. The minimum inhibitory concentrations of selected antibiotics were determined by broth microdilution method. The presence of blaOXA-48, blaKPC, blaNDM, and blaVIM carbapenemase genes was examined by PCR, and clonal relatedness of CRKP isolates was investigated by pulsed-field gel electrophoresis (PFGE) analysis. blaOXA-48 was the most frequent carbapenemase gene (72%), followed by blaNDM (31%). None of the isolates harbored blaKPC and blaVIM genes. PFGE separated the majority of isolates into 10 clusters, including the major clusters A and B, carrying blaOXA-48, and clusters C and D, carrying blaNDM, and 4 isolates had a unique PFGE pattern. An increased rate of colistin resistance (50%) was detected among the isolates. Tigecycline was found to be the most active agent against CRKP isolates. Our results revealed that high prevalence of blaOXA-48 and blaNDM carbapenamses and resistance to colistin are alarming threats, necessitating an immediate action to prevent the spread of carbapenem-colistin-resistant K. pneumoniae isolates in Iran.

Antimicrobial resistance and pulsed-field gel electrophoresis typing of Vibrio parahaemolyticus isolated from shrimp mariculture environment along the east coast of China

Environmental antimicrobial resistance (AMR) has drawn increasing attention due to its great risk to human health. The aim of this study was to investigate AMR and genotyping of Vibrio parahaemolyticus isolates (n = 114) recovered from shrimp mariculture environment in China. The isolates exhibited a high rate of resistance to streptomycin (78.9%), ampicillin (64.9%) and gentamicin (53.5%). Furthermore, multi-drug resistance was highly prevalent (61.4%), in which 95.9% of these ampicillin-resistant isolates were primarily mediated by blaCARB-17. Surprisingly, doxycylcine, florfenicol, and trimethoprim/sulfamethoxazole (TMP/SMZ) resistance genes occurred in susceptible isolates. Moreover, 114 isolates were grouped into unique pulsed field gel electrophoresis patterns. These findings suggest the need for the prudent use of antimicrobial agents on mariculture farms, in order to control the dissemination of antimicrobial resistant V. parahaemolyticus.

Diversity of Staphylococcus pseudintermedius in carriage sites and skin lesions of dogs with superficial bacterial folliculitis: potential implications for diagnostic testing and therapy.

Staphylococcus pseudintermedius is genotypically diverse within the canine population and multiple strains may colonize individual dogs at any given time. If multiple strains with distinct antimicrobial resistance profiles are present in superficial bacterial folliculitis (SBF), sampling a single skin lesion for culture and antimicrobial susceptibility testing (AST) might be inadequate to select effective therapy. To investigate S. pseudintermedius diversity in carriage sites and lesions of dogs with SBF. Fourteen dogs with SBF. Staphylococcus pseudintermedius isolates obtained from perineum, gingiva and four to six skin lesions per dog were subjected to pulsed-field gel electrophoresis (PFGE) and AST to assess diversity between lesions. For two dogs, 14-16 isolates per lesion were included in the analysis to assess diversity within lesions. Analysis of one isolate per lesion revealed one to four strains displaying unique PFGE profiles, and up to three unique antimicrobial resistance (AMR) profiles for each dog. Multiple pustules from the same dog always harboured the same strain, whereas papules, crusts and collarettes did not. Up to four strains with distinct AMR profiles were isolated from the same lesion in two dogs. In 12 dogs, at least one carriage site strain also was represented in lesions. Lesions of SBF may harbour multiple S. pseudintermedius strains with distinct antimicrobial resistance profiles. Pustules are the best target for bacterial culture. It remains unclear whether isolation of different strains from other lesion types is a consequence of contamination or co-infection by multiple strains.

Molecular Characterization of Salmonella from Beef Carcasses and Fecal Samples from an Integrated Feedlot and Abattoir in Mexico

Nontyphoid Salmonella strains are some of the leading causes of foodborne illnesses worldwide; however, there is very limited information on the presence and characteristics of Salmonella in the food production chain in developing countries. In this study, pulsed-field gel electrophoresis (PFGE) was used for molecular subtyping and for monitoring the ecology and transmission of Salmonella isolates in a slaughter facility in Mexico in an attempt to determine specific steps that need to be improved to reduce Salmonella contamination in beef carcasses. A total of 94 isolates from a Salmonella stock culture collection originally obtained from a single vertically integrated feedlot and beef abattoir in Mexico were analyzed. A total of 26 unique PFGE patterns were identified, 38.5% of them corresponding to a single serotype. High concordance (88.4%) was found between serotype and PFGE banding subtype. Salmonella Kentucky and Salmonella Give were the most clonal subtypes in this study, and Salmonella Muenster was the most diverse, with 11 banding patterns identified. A total of 73.7, 70.6, and 85.7% of the PFGE subtypes identified from preevisceration, precooler, and chilled carcasses, respectively, were identified only at those specific points and not at any previous or subsequent steps of the slaughter process, suggesting that each step is in itself a source of Salmonella contamination. Salmonella Mbandaka was more likely to be recovered from feces than from any of the steps of the slaughter process. The genetic diversity and distribution of PFGE subtypes in the processing facility highlight the need to implement antimicrobial interventions and improve sanitation procedures at various points to avoid further Salmonella dissemination into the meat supply.

Clostridium difficile Molecular Epidemiology in a Prospective Cohort of Canadian Children Compared with Cases of C. difficile Infection

Background Clostridium difficile is a notorious nosocomial pathogen, but little is known regarding the colonization commonly observed in children. It is suspected that C. difficile carriage in infants is a reservoir for toxigenic strains. To test this hypothesis, we sought to determine the genetic relatedness between a prospective cohort of C. difficile toxin gene positive healthy children and those with acute gastroenteritis (AGE) and strains identified in adult and pediatric C. difficile infection (CDI) cases from Alberta, Canada. Additionally, we compared C. difficile toxin production in healthy and AGE children.Methods C. difficile was cultured from 97 hospitalized CDI cases (n = 79 adult; n = 18 pediatric) from stool samples tested positive for toxigenic C. difficile by C.DIFF QUIK CHEK COMPLETE® enzyme immunoassay (EIA) in 2015 and samples tested positive for toxin genes by the Luminex xTAG® Gastrointestinal Pathogen Panel from a prospective cohort of 59 children with AGE seeking care at the emergency department and 17 healthy children attending public health clinics. Isolates were then characterized by PCR-ribotyping, pulsed-field gel electrophoresis (PFGE), PCR of the tcdA, tcdB, tcdC, and cdtB genes and C. difficile toxigenicity by EIA for a subset of 14 healthy and 45 AGE children.ResultsRibotype 106 was predominant among all pediatric isolates (n = 21, 27.6% AGE and healthy children; n = 5, 27.8% pediatric CDI) and ribotype 027 in adult CDIs (n = 35, 44.3%). Eighteen ribotypes were shared between children and CDI cases (n = 134, 77.5%). Sixteen unique ribotype and PFGE patterns (n = 84, 48.6%) were identified in two or more cohorts. Similar toxin gene profiles were observed across the three cohorts, but adult CDI isolates had a higher proportion of binary toxin positive isolates (n = 42, 53.2%) compared with children (n = 3, 3.95%) and pediatric CDI (n = 0). C. difficile toxigenicity was similar (P = 0.23) amongst the subset of healthy (n = 6, 42.9%) and AGE (n = 28, 62.2%) children.ConclusionProduction of C. difficile toxins in children was not significantly associated with symptoms of AGE. C. difficile strains found in children were similar to those from CDI cases; especially pediatric cases. This suggests that strains might be shared, but the development of CDI may be related to factors other than C. difficile strain type.Disclosures All authors: No reported disclosures.

Emergence of methicillin-resistant Staphylococcus aureus SCCmec type IV/V epidemic clones in a large teaching hospital in China

To investigate the staphylococcal cassette chromosome mec (SCCmec) genotype and molecular epidemiological characteristics of healthcare-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) in a large teaching hospital in China. From January 2012 to December 2012, a total of 71 nonduplicate HA-MRSA were collected in a teaching hospital in Changsha, China. SCCmec types were determined by multiplex PCR, and Panton-Valentine leukocidin (PVL) gene was detected by PCR. The homology among the tested isolates was determined using pulsed-field gel electrophoresis (PFGE). Of the 71 HA-MRSA isolates, 49 (69.0%) carried SCCmec III, 10 (14.1%) carried SCCmec IV, 3 (4.2%) carried SCCmec V and 3 (4.2%) carried SCCmec II; the remaining 6 isolates were not typeable by PCR. Compared with patients having SCCmec I/II/III MRSA infections, those with SCCmec IV/V MRSA infections had a significantly younger age and a similar duration of hospital stay before the first MRSA-positive culture and total hospital stay. PVL genes were strongly associated with SCCmec type IV/V MRSA infections. HA-SCCmec IV/V MRSA strains showed a greater susceptibility to rifampicin, gentamicin, levofloxacin, ciprofloxacin, and tetracycline than HA-SCCmec I/II/III MRSA strains. The 13 HA-SCCmec IV/V MRSA isolates formed one large group at the 55% similarity level. Three PFGE clusters with a similarity index of 85% or more were identified, and unique PFGE profiles were observed in 4 isolates. This is the first report of HA-MRSA isolates carrying SCCmec V in Chinese hospitals. SCCmec types IV and V MRSA clones have emerged in Chinese hospitals, which urges more rigorous surveillance of their spread in healthcare facilities in China.

Characterizing Salmonella Contamination in Two Rendering Processing Plants

A microbiological investigation on Salmonella contamination was conducted in two U.S. rendering plants to investigate the potential cross-contamination of Salmonella in the rendering processing environment. Sampling locations were predetermined at the areas where Salmonella contamination may potentially occur, including raw materials receiving, crax (rendered materials before grinding process) grinding, and finished meal loading-out areas. Salmonella was either enumerated directly on xylose lysine Tergitol 4 agar plates or enriched in Rappaport-Vassiliadis and tetrathionate broths. The presumptive Salmonella isolates were confirmed using CHROMagar plating and latex agglutination testing and then characterized using pulsed-field gel electrophoresis, serotyping, and biofilm-forming determination. Among 108 samples analyzed, 79 (73%) samples were Salmonella positive after enrichment. Selected Salmonella isolates (n = 65) were assigned to 31 unique pulsed-field gel electrophoresis patterns, with 16 Salmonella serotypes, including Typhimurium and Mbandaka, identified as predominant serotypes and 10 Salmonella strains determined as strong biofilm formers. Our results indicated that the raw materials receiving area was the primary source of Salmonella and that the surfaces surrounding crax grinding and finished meal loading-out areas harbor Salmonella in biofilms that may recontaminate the finished meals. The same Salmonella serotypes found in both raw materials receiving and the finished meal loading-out areas suggested a potential of cross-contamination between different areas in the rendering processing environment.

Molecular Characterization of Carbapenemase-Nonproducing Clinical Isolates of Escherichia coli (from a Thai University Hospital) with Reduced Carbapenem Susceptibility.

Twelve nonreplicate carbapenemase-negative ertapenem (ETP)-nonsusceptible (CNENS) Escherichia coli isolates obtained at a Thai university hospital between 2010 and 2014 were characterized and compared with 2 carbapenemase-producing E. coli isolates from the same hospital. Eight unique pulsed-field gel electrophoresis patterns were obtained. All the isolates produced CTX-M-15 β-lactamase and 2 either coexpressed CMY-2 cephalosporinase or showed increased efflux pump activity. Amino acid sequence analysis revealed that an OmpF defect (in 7 isolates) due to mutations generating truncated proteins or an IS1 insertion was more prevalent than a defect in OmpC was (no truncated proteins detected). Seven out of 10 isolates possessing OmpC variants with any OmpF defect were weakly ETP-resistant (minimum inhibitory concentrations [MICs] of 1-4 μg/mL) and imipenem (IPM)- and meropenem (MEM)-susceptible (MICs 0.125-0.5 μg/mL). Two isolates with ompC PCR-negative results and an OmpF defect showed higher carbapenem MICs (8-32, 1-8, and 1-4 μg/mL for ETP, IPM, and MEM, respectively) with the highest MICs associated with the additional efflux pump activity. Both carbapenemase producers possessing CTX-M-15 and a porin background identical to that in the CNENS isolates showed ETP, IPM, and MEM MICs of 128-256, 8, and 2-32 μg/mL, respectively. These findings suggest that a porin defect combined with CTX-M-15 production is the major mechanism of low carbapenem susceptibility among our CNENS isolates, which have potential to become strongly carbapenem-resistant because of additional carbapenemase or efflux pump activities.

Molecular and Phenotypic Characterization of Multidrug-Resistant Clones of Staphylococcus epidermidis in Iranian Hospitals: Clonal Relatedness to Healthcare-Associated Methicillin-Resistant Isolates in Northern Europe.

The aim of the study was to investigate the molecular epidemiology of Staphylococcus epidermidis in Iranian hospitals and to compare the genotypes with a previously characterized collection of >1,300 S. epidermidis isolates of nosocomial and community origin from Northern Europe, Australia, and USA. In total, 82 clinical S. epidermidis isolates from three Iranian hospitals were examined by multilocus sequence typing, pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing. In addition, antimicrobial susceptibility, the presence of the ica operon, and the predilection to biofilm formation were assessed. Three predominant PFGE clones were found. The PFGE patterns of the most common sequence type (PFGE type 040-ST2) showed 80% similarity to multidrug-resistant S. epidermidis (MDRSE) clinical isolates from eight hospitals in Northern Europe. The second most common (PFGE 024-ST22) showed an unique PFGE pattern, whereas the third most predominant genotype (PFGE 011-ST5) proved indistinguishable to the PFGE Co-ST5 identified in five hospitals in Northern Europe. In conclusion, the study documented the dissemination of three MDRSE clones within and between hospitals in Iran and revealed an intercontinental spread of two clonal multidrug-resistant lineages (ST2 and ST5) in the hospital environment. Isolates of the predominant clones were significantly more frequently associated with multidrug-resistance and biofilm formation compared to nonclonal isolates. Further studies are needed to explore and characterize the genetic traits that enable these successful MDRSE clones to persist and disseminate worldwide in the healthcare settings.

KPC-Producing Klebsiella pneumoniae Isolates in Croatia: A Nationwide Survey.

In the last few years, Klebsiella pneumoniae strains producing K. pneumoniae carbapenemase (KPC) enzymes have emerged as important multidrug-resistant pathogens in hospitalized patients. This report describes KPC-producing isolates collected through the Croatian antimicrobial resistance surveillance program in the early stage of their dissemination in Croatia. Forty-eight KPC-producing K. pneumoniae isolates, collected during a period from February 2011 to August 2013, were analyzed in this study. Antimicrobial susceptibility profiles were determined using disk diffusion and E-test. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used for epidemiological analysis. Identification of β-lactamase genes and associated antibiotic resistance mechanisms was performed by polymerase chain reaction and positive products were sequenced. Localization of blaKPC was investigated by S1 PFGE and Southern hybridization. Of 40 participating centers in Croatia, KPC isolates were recorded in 9 of them. They all had multidrug-resistant phenotype, but showed varying levels of resistance to carbapenems. All isolates displayed ST258, and PFGE showed that all but one were closely related. All isolates harbored blaKPC-2. Isolate with a unique PFGE pattern produced TEM-1, while others produced TEM-116. All isolates harbored blaSHV-11, but were negative for blaCTX-M and blaAmpC genes. All isolates contain one KPC-harboring plasmid, ranging in size from ∼60 to ∼210 kb, characterized as FIIs and IncR. This report describes that the early stage of KPC-producing K. pneumoniae dissemination in Croatia is associated with a prolific PFGE type belonging to ST258. So far, the spread of an outbreak strain is limited to the northwest region of the country.

Draft Genome Sequence of Salmonella enterica subsp. enterica Serovar Give, Isolated from an Imported Chili Powder Product

We report the genome sequence of Salmonella enterica subsp. enterica serovar Give (CFSAN012622), isolated from imported chili powder in 2014. This genome contains genes previously reported to be specific only to S. enterica serovar Enteritidis. This strain shows a unique pulsed-field gel electrophoresis (PFGE) pattern clustering with serovar Enteritidis (JEG X01.0005).

Carbapenem non-susceptible enterobacteriaceae in Quebec, Canada: results of a laboratory surveillance program (2010-2012).

The emergence and spread of carbapenemase-producing Enterobacteriaceae (CPE) represent a major public health concern because these bacteria are usually extensively resistant to most antibiotics. In order to evaluate their dissemination in Quebec, a surveillance program was introduced in 2010. We report the molecular and epidemiological profiles of CPE isolates collected. Between August 2010 and December 2012, a total of 742 non-duplicate isolates non-susceptible to carbapenems were analysed. AmpC β-lactamase and metallo-β-lactamase production were detected by Etest and carbapenemase production by the modified Hodge test (MHT). Antibiotic susceptibility profiles were determined using broth microdilution or Etest. Clonality of Klebsiella pneumoniae carbapenemase (KPC) strains was analyzed by pulsed-field gel electrophoresis (PFGE). The presence of genes encoding carbapenemases as well as other β-lactamases was detected using PCR. Of the 742 isolates tested, 169 (22.8%) were CPE. Of these 169 isolates, 151 (89.3%) harboured a bla KPC gene while the remaining isolates carried bla SME (n = 9), bla OXA-48 (n = 5), bla NDM (n = 3), and bla NMC (n = 1) genes. Among the 93 KPC strains presenting with a unique pattern (unique PFGE pattern and/or unique antibiotics susceptibility profile), 99% were resistant to ertapenem, 95% to imipenem, 87% to meropenem, 97% to aztreonam, 31% to colistin and 2% to tigecycline. In 19 patients, 2 to 5 KPC strains from different species or with a different PFGE pattern were isolated. CPE strains were present in the province of Quebec with the majority of strains harbouring KPC. Alternately, SME, OXA-48 and NMC containing strains were rarely found.

Clonal and horizontal spread of the blaOXA-232 gene among Enterobacteriaceae in a Korean hospital

All 16 Klebsiella pneumoniae isolates and both Escherichia coli isolates harbored the blaOXA-232 and blaCTX-M-15 genes. Furthermore, all 16 K. pneumoniae isolates belonged to a unique pulsed-field gel electrophoresis clone and were assigned to an identical sequence type (ST14). The 2 E. coli isolates were identified as ST131 and ST457. The blaOXA-232 gene underwent horizontal transfer to E. coli isolates via a conjugative ColE-type plasmid. The introduction of this K. pneumoniae ST14 strain to the Korean hospital was attributed to an index patient who was likely colonized during a prior hospitalization in India.

Antibiotic resistance traits and molecular subtyping of Staphylococcus aureus isolated from raw sheep milk cheese.

The main objective of the present research was to evaluate the antibiotic resistance profiles of Staphylococcus aureus isolated from raw sheep milk cheese. A total of 150 strains were isolated from curd cheese samples and identified as S. aureus. The survey on antibiotic resistance was carried out on 47 strains, selected among isolates showing differences in the banding pattern after Pulsed Field Gel Electrophoresis (PFGE) screening or, belonging at the same pulsotype but isolated from different cheese samples. On selected strains antimicrobial resistance against ampicillin, penicillin, cloxacillin, tetracycline, erythromycin, and vancomycin was assessed by broth microdilution method. The presence of the genes coding for antibiotic resistance and virulence factors (agr alleles, sea-see, and tst) was also investigated by PCR. Thirty-one isolates belonging to agrI and agrIII groups carried at least one gene coding for enterotoxins or toxic shock syndrome toxin. Approximately 60% of the selected strains were susceptible to the tested antibiotics. Twelve of 47 isolates showed multiple resistance against ampicillin and penicillin. Only 1 strain, represented by a unique PFGE profile showed simultaneous resistance to ampicillin, penicillin and cloxacillin. Single resistance against tetracycline was found in 5 isolates belonging to 2 different pulsotypes. The results of this study suggest that the recovery of S. aureus resistant strains in raw milk cheese samples is quite common but it is limited to few antibiotic classes, mainly β-lactams and tetracyclines. None of the strains showed resistance to erythromycin and vancomycin. The present research contributes to increase the knowledge on the diffusion of antibiotic resistant S. aureus strains isolated from raw sheep milk cheeses. These can be regarded as a vehicle for the introduction of strains of animal origin to humans through food.

Multilocus Sequence Typing Scheme versus Pulsed-Field Gel Electrophoresis for Typing Mycobacterium abscessus Isolates

Outbreaks of infections by rapidly growing mycobacteria following invasive procedures, such as ophthalmological, laparoscopic, arthroscopic, plastic, and cardiac surgeries, mesotherapy, and vaccination, have been detected in Brazil since 1998. Members of the Mycobacterium chelonae-Mycobacterium abscessus group have caused most of these outbreaks. As part of an epidemiological investigation, the isolates were typed by pulsed-field gel electrophoresis (PFGE). In this project, we performed a large-scale comparison of PFGE profiles with the results of a recently developed multilocus sequence typing (MLST) scheme for M. abscessus. Ninety-three isolates were analyzed, with 40 M. abscessus subsp. abscessus isolates, 47 M. abscessus subsp. bolletii isolates, and six isolates with no assigned subspecies. Forty-five isolates were obtained during five outbreaks, and 48 were sporadic isolates that were not associated with outbreaks. For MLST, seven housekeeping genes (argH, cya, glpK, gnd, murC, pta, and purH) were sequenced, and each isolate was assigned a sequence type (ST) from the combination of obtained alleles. The PFGE patterns of DraI-digested DNA were compared with the MLST results. All isolates were analyzable by both methods. Isolates from monoclonal outbreaks showed unique STs and indistinguishable or very similar PFGE patterns. Thirty-three STs and 49 unique PFGE patterns were identified among the 93 isolates. The Simpson's index of diversity values for MLST and PFGE were 0.69 and 0.93, respectively, for M. abscessus subsp. abscessus and 0.96 and 0.97, respectively, for M. abscessus subsp. bolletii. In conclusion, the MLST scheme showed 100% typeability and grouped monoclonal outbreak isolates in agreement with PFGE, but it was less discriminative than PFGE for M. abscessus.

Tracking Campylobacter contamination along a broiler chicken production chain from the farm level to retail in China

This study was conducted to determine the prevalence and distribution of Campylobacter species along a broiler production chain from farm to retail, and to evaluate the antimicrobial resistance profile of Campylobacter isolates. A total of 259 Campylobacter isolates (C. jejuni n=106, C. coli n=153) were isolated from broiler ceca samples (72.5%, 103/142), broiler carcasses (34.1%, 46/135), and retail broiler meat (31.3%, 40/128) samples collected in Shanghai, China. Minimal inhibitory concentrations of six antimicrobials were determined using the agar dilution method. High prevalence of resistance to ciprofloxacin (C. jejuni: 99.1%;C. coli: 100%) and tetracycline (C. jejuni: 100%;C. coli: 98.7%) was detected among the C. jejuni and C. coli isolates. The vast majority of C. coli were resistant to clindamycin (92.2%), gentamicin (95.4%), and erythromycin (94.1%), but only 25.5%, 53.8%, and 16.0% of C. jejuni exhibited resistance to these three antimicrobials, respectively. In contrast, the prevalence of florfenicol resistance in C. jejuni (37.7%) was significantly higher than that in C. coli (7.8%) (P<0.05). It is noteworthy that all Campylobacter isolates were resistant to one or more antimicrobials, and 71.7% of C. jejuni and 98.0% of C. coli isolates exhibited multi-drug resistance (resistant to three or more antimicrobials). Fifty-five C. jejuni and sixty C. coli isolates, selected from different production stages, species, and antimicrobial resistance patterns, were analyzed by pulsed field gel electrophoresis (PFGE), among which 15 unique PFGE patterns (PFGE patterns represented by a single strain) and 31 clusters (PFGE patterns represented by multiple strains) were detected. Furthermore, nearly all of the PFGE patterns of the Campylobacter strains isolated from retail broiler meats overlapped with those of the strains from ceca and slaughterhouse carcasses. Together, these findings revealed the high prevalence of Campylobacter species in a broiler chicken production chain, and the concerning situation of antimicrobial resistance in Campylobacter species. The findings also indicated that Campylobacter isolates from retail broiler meats were associated with fecal contamination in the slaughterhouse, underlying the need for improved measures for reducing carcass contamination in slaughter plants.