Phylogenetic groups and cephalosporin resistance genes of Escherichia coli from diseased food-producing animals in Japan

A total of 318 Escherichia coli isolates obtained from different food-producing animals affected with colibacillosis between 2001 and 2006 were subjected to phylogenetic analysis: 72 bovine isolates, 89 poultry isolates and 157 porcine isolates. Overall, the phylogenetic group A was predominant in isolates from cattle (36/72, 50%) and pigs (101/157, 64.3%) whereas groups A (44/89, 49.4%) and D (40/89, 44.9%) were predominant in isolates from poultry. In addition, group B2 was not found among diseased food-producing animals except for a poultry isolate. Thus, the phylogenetic group distribution of E. coli from diseased animals was different by animal species. Among the 318 isolates, cefazolin resistance (minimum inhibitory concentrations: ≥32 μg/ml) was found in six bovine isolates, 29 poultry isolates and three porcine isolates. Of them, 11 isolates (nine from poultry and two from cattle) produced extended spectrum β-lactamase (ESBL). The two bovine isolates produced blaCTX-M-2, while the nine poultry isolates produced blaCTX-M-25 (4), blaSHV-2 (3), blaCTX-M-15 (1) and blaCTX-M-2 (1). Thus, our results showed that several types of ESBL were identified and three types of β-lactamase (SHV-2, CTX-M-25 and CTX-M-15) were observed for the first time in E. coli from diseased animals in Japan

Proportion of extended-spectrum ß-lactamase-producing Enterobacteriaceae in community setting in Ngaoundere, Cameroon

BACKGROUND: There is no information regarding the resistance mechanisms of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae in community setting in Cameroon. The current study aimed to determine the proportion of ESBLs in Enterobacteriaceae isolated in the community and to analyse some risk factors associated with ESBL carriage. METHODS: Faecal samples were collected from 208 different outpatients and 150 healthy student volunteers between 3 January and 3 April 2009. Enterobacterial isolates resistant to third-generation cephalosporins were screened for ESBL production by the double-disk synergy test. Presumptive ESBL-producing isolates with positive synergy test were identified by Mass Spectrometry using the BioTyper MALDI-TOF. For such ESBL positive isolates, antibiotic susceptibility was determined by the Vitek 2 system. PCR and sequencing were performed for the detection of different types of ESBL genes in presumptive ESBL-producing isolates. Statistical methods were used for the univariate calculation of risk factors. RESULTS: During the study period, a total of 358 faecal samples were analysed; 58 of such samples (16%) showed an ESBL phenotype and were confirmed by PCR. The proportion of ESBL producers in faecal carriage was statistically different between outpatients and student volunteers (23.1% vs. 6.7%: p < 0.000). According to a univariate analysis, previous use of antibiotics (ciprofloxacin) appeared to be a risk factor for ESBL carriage (p < 0.05).Escherichia coli was the species most frequently isolated among the ESBL producers in outpatients (66.7%) and student volunteers (90%). Isolates showed additional resistance to gentamicin, ciprofloxacin and trimethoprim/sulfamethoxazole but none of them was resistant to temocillin, amikacin or meropenem. Most of the strains (97%) produced a CTX-M group 1 enzymes [CTX-M-15 (98%) or CTX-M-1 (2%)] and the remaining strains produced SHV-12 enzyme (3%). CONCLUSIONS: The use of drugs such as amoxicillin, ciprofloxacin and trimethoprim/sulfamethoxazole does not seem appropriate for empirical treatment because of emerging resistance. The implementation in Cameroon or in other African countries of methods of screening ESBL-producing organisms in routine laboratories is of great importance in order for us to offer patients appropriate treatment and for infection control efforts to succeed

How to detect carbapenemase producers? A literature review of phenotypic and molecular methods

© 2014 Elsevier B.V. This review describes the current state-of-art of carbapenemase detection methods. Identification of carbapenemases is first based on conventional phenotypic tests including antimicrobial susceptibility testing, modified-Hodge test and carbapenemase-inhibitor culture tests. Second, molecular characterization of carbapenemase genes by PCR sequencing is essential. Third, innovative biochemical and spectrometric detection may be applied

Prevalence and spread of extended-spectrum β-lactamase-producing

During April 2010 and June 2010, 334 Enterobacteriaceae isolates from 590 participants (outpatients, inpatients, inpatient carers, hospital workers and members of their households) were collected from faecal samples. Based on b-lactamase pattern, origin of strains and the relationship between participants, 44 isolates of extended-spectrum b-lactamase (ESBL)-producing Escherichia coli and Klebsiella pneumoniae were selected from 44 participants (in Ngaoundere Protestant Hospital and Ngaoundere Regional Hospital, Cameroon). To determine the relatedness of bacterial strains, these isolates were fingerprinted using the automated, repetitive-sequenced-based PCR-based DiversiLab system. Subsequently, E. coli isolates that had undergone DiversiLab analysis were examined with respect to their phylogenetic group and detection of the ST131 clone to shed light on the epidemiology of these isolates in the Ngaoundere hospitals. The prevalence of faecal carriage of ESBL-producing Enterobacteriaceae among the study participants was 54.06%. According to participant groups, the prevalence of faecal carriage was also high (outpatients 45%; inpatients 67%; inpatient carers 57%; hospital workers 44%; and members of their households 46%). Analysis of the molecular epidemiology of ESBL-producing E. coli and K. pneumoniae showed a close relationship of the isolates between related and nonrelated individuals. In addition, DiversiLab results of E. coli identified four related isolates (4/22) from cluster III belonging to the epidemiologically important clone ST131. Our results highlight the importance of outpatients, inpatients, their carers, hospital workers and their families as reservoirs of ESBLproducing Enterobacteriaceae