Cefotaximase Research Articles

Distribution of Class A Extended-Spectrum β-Lactamases Among Pseudomonas aeruginosa Clinical Strains Isolated from Ardabil Hospitals

Background: Currently, the emergence of extended-spectrum β-lactamase (ESBL)-producing bacteria is becoming a major threat to patients in the hospital and community. Such enzymes have been recently detected in Pseudomonas aeruginosa, but there is no epidemiological data on the prevalence of ESBL-producing clinical isolates in the hospitals of Ardabil City (Iran). Objectives: This study aimed to determine the phenotypic and genotypic prevalence of class A ESBL-producing P. aeruginosa strains in Ardabil City. Methods: A total of 120 clinical isolates of P. aeruginosa collected from Ardabil hospitals were used in this study. Phenotypic detection of class A ESBL-producing P. aeruginosa isolates was performed using a double-disk synergy test. In addition, the detection of class A ESBL-encoding genes, including Pseudomonas extended resistant (PER), Vietnamese extended-spectrum β-lactamase (VEB), temoniera (TEM), sulfhydryl variable (SHV), cefotaximase (CTX-M), guyana extended-spectrum β-lactamase (GES), and Pseudomonas-specific enzyme (PSE), was performed using the polymerase chain reaction (PCR). Results: The prevalence of class A ESBL-producing P. aeruginosa strains was 8.3% (10 out of 120) based on the double-disk synergy test. However, 40% (48 out of 120) of these isolates were found to carry genes encoding class A ESBLs based on PCR. Among 48 class A ESBL-positive strains, the prevalence of PSE, TEM, VEB, CTX-M, and PER genes were 64.6% (31/48), 25% (12/48), 4.2% (2/48), 4.2% (2/48), and 2% (1/48), respectively. However, the frequency of other class A ESBL genes (SHV and GES genes) was 0%. Conclusions: Our results confirmed the presence of class A ESBL-producing P. aeruginosa strains in the hospital environment of Ardabil. On the other hand, the use of molecular tests can be a more precise and reliable method than phenotypic ones to identify these resistant strains and prevent the emergence of antibiotic resistance and ensuing treatment failure.

Co-existence of extended-spectrum β-lactamases blaCTX-M-9 and blaCTX-M-15 genes in Salmonella species isolated from febrile and diarrhoeagenic patients in Lagos, Nigeria: a cross-sectional study

BackgroundResistance to different antimicrobial classes by Salmonella species has generated a global public health concern. The spread of extended-spectrum β-lactamases (ESBLs) blaCTX gene variants is also increasing. This study aimed to investigate the antibiotic resistance and the carriage of blaCTX-M-9 and blaCTX-M-15 as well as the quinolone resistance gene (qnrB19) among Salmonella species from hospitalised patients in Lagos, Nigeria.MethodsIn this cross-sectional study from April 2021 to August 2021, a total of 508 samples were collected from hospitalised patients. The samples were subjected to standard microbiological investigation. All the isolates were identified using API 20E kits and real-time polymerase chain reaction (RT-PCR). The in vitro antibiotic susceptibility testing (AST) was investigated using the disk diffusion method. Detection of antibiotic resistance and virulence gene makers was conducted using RT-PCR.ResultsIn total, 24 Salmonella species were identified. All the isolates were non-typhoidal Salmonella isolates. None of the isolates screened was S. Typhi and S. Paratyphi. Most of the isolates were susceptible to imipenem, ciprofloxacin, ofloxacin and gentamycin, while a high level of resistance to all cephalosporins, penicillin, and some carbapenems was observed. In total, 79.2% (19/24) of the Salmonella isolates harboured the blaCTX-M variant including 54.2% (13/24) blaCTX-M-9 and 12.5% (3/24) blaCTX-M-15, while co-habitation of blaCTX-M-9 and blaCTX-M-15 was observed in 12.5% (3/24) of the isolates, respectively. None of the isolates harboured quinolone-resistant qnrB19 gene and virulence gene stn. However, invA gene was present in 66.7% (16/24) of all isolates.ConclusionsThis study is considered the first report of blaCTX-M-9 and blaCTX-M-15 variants in Salmonella species in Nigeria. The continued existence of cefotaximase (CTX-M)-producing Salmonella within our environment calls for the prudent use of cephalosporins.

Prevalence and Resistance Profile of Muenchen Cefotaximase (CTX-M) Group 1 Extended Spectrum Beta-Lactamase (ESBL)-Producing Uropathogenic <i>Escherichia coli</i> Strains in Dakar, Senegal

Background: Extended-spectrum beta-lactamase (ESBL) producing bacteria are a real public health problem, particularly in Africa. Among these ESBLs, there are the Muenchen Cefotaximase (CTX-M) described all over the world of which the most frequent is the CTX-M of group 1 particularly the CTX-M-15 variant. The objective of this study was to determine the prevalence of CTX-M group 1 ESBL-producing Escherichia coli strains and to test their antibiotics susceptibility profile. Methodology: A retrospective cross-sectional descriptive study was conducted to detect ESBL-secreting Escherichia coli strains by the synergy test. Identification of CTX-M type ESBL from group 1 was performed using the NG-Test CTX-M rapid diagnostic test (NG-Biotech®). Antibiotic susceptibility profile was determined using CA-SFM/EUCAST guidelines 2019. Data entry and statistical analysis were performed with Excel version 2010 and SPSS 20.0 respectively. Results: Eighty-two ESBL-producing Escherichia coli strains were tested. A group 1 CTX-M ESBL was detected in 75.6% of the strains (n = 62). These strains were highly resistant to cefotaxim (100%), aztreonam (100%), ceftazidim (85.4%) and cefepim (66.1%). They were also resistant to quinolones, gentamycin and sulfadoxine-trimethoprim combination. However, these strains showed sensitivity to ertapenem (100%), cefoxitin (69.3%), tigecyclin (66%), and amikacin (66.1%). The combination of piperacillin and tazobactam was active on 30.6% of the strains against 6.4% for the combination of amoxicillin and clavulanic acid. Conclusion: The CTX-M type ESBL of group 1 was present in the majority of ESBL-producing Escherichia colis trains. Despite the production of this enzyme conferring resistance to most beta-lactam antibiotics, some antibiotics remain active to treat infections caused by these germs.

Klebsiella infections in a pediatric intensive care unit: incidence, antimicrobial susceptibility, and resistance genes

BackgroundInfections with multidrug-resistant K. pneumoniae is associated with high morbidity and mortality especially among critically ill patients. This was the main principle to conduct a detailed study about this organism, its resistance pattern, and type of its resistance genesSubjects and methodsA cross-sectional study was carried out in a pediatric intensive care unit on patients with age range from 1 month to 12 years over a period of 1 year with positive K. pneumoniae using standard microbiological culture and antibiogram sensitivity testing. All collected samples were processed using multiplex PCR technique to identify the most relevant resistant genes.ResultsForty-four patients had 54 positive cultures for K. pneumoniae, out of which 17 patients (38.6%) passed away. The most prevalent-resistant gene was New Delhi metallo-beta lactamase (NDM) gene (65.4%) followed by cefotaximase (CTX-M) gene (57.7%). Extensively drug-resistant K. pneumoniae was detected in (15.9%) of the results and was proved to be independent risk factor increasing mortality odds 139 folds.ConclusionThe evolution of resistance of Klebsiella pneumoniae was proved to be associated with a high mortality rate. Continuous widespread surveillance of Klebsiella pathogen focusing on identification of resistance genes and antibiotic resistance pattern is highly recommended.

Prevalence of Fecal Carriage of Extended-Spectrum β-Lactamase-Producing Enterobacteriaceae Among School Children in South Sulawesi, Indonesia

Background: Fecal carriage of extended-spectrum β-lactamase (ESBL)-producing bacteria is a potential risk for transmission and infection. Genotypes known to be associated with ESBL-producing Enterobacteriaceae are cefotaximases (CTX-M), temoniera (TEM), and sulfhydryl variable (SHV). Unfortunately, data on ESBL prevalence in Indonesia, especially in South Sulawesi, is still limited, so further research on the community is needed. Objectives: This study aimed to investigate the prevalence of fecal carriage of ESBL-producing Enterobacteriaceae among school children in South Sulawesi, Indonesia. Methods: The research was conducted among school-children in South Sulawesi, Indonesia. Detection of ESBL gene using polymerase chain reaction (PCR) methods. A total of 245 stool samples were collected. Results: The prevalence of fecal carriage of ESBL-producing Enterobacteriaceae among school children was 76.7% (188/245). Genotyping of EBSL-producing Enterobacteriaceae encoding genes using PCR found that TEM genes, 92.6% (174/188), were higher than SHV genes, 38.8% (73/188) and CTX-M genes, 4.3% (8/188). It was also revealed a combination of ESBL-producing genes of Enterobacteriaceae. The most combination genes were found in TEM + SHV genes, including 55 of 188 (29.26%). Conclusions: The presence of ESBL gene careers suggests that antibiotic resistance has spread in the community, which needs to be of concern since it can be an ESBL gene reservoir that can be transmitted to many pathogenic bacteria.

First Detection of Carbapenem-Resistant Escherichia fergusonii Strains Harbouring Beta-Lactamase Genes from Clinical Samples.

Recently discovered extraintestinal Escherichia fergusonii obtained from non-clinical samples has exhibited the potential for acquiring multiple beta-lactamase genes, just like many extraintestinal Escherichia coli strains. Albeit, they are often omitted or classified as E. coli. This study aimed to, therefore, identify carbapenem-resistant extended-spectrum beta-lactamase (ESBL) producing E. fergusonii isolates from clinical samples, determine their evolutionary relatedness using 16S rRNA sequencing analysis and screen for beta-lactamase genes. A total of 135 septic wound samples were obtained from patients on referral at a General Hospital in Lagos, Nigeria. For the phenotypic identification of isolates from culture-positive samples, morphological, and physiological tests were carried out. Identities of the isolates harbouring beta-lactamase genes were assigned to their genus strains using the 16S rRNA sequencing. The Kirby Bauer disc diffusion technique and double-disc synergy test were used to screen isolates for multidrug resistance and ESBL production. Carbapenem-resistant ESBL producing isolates were screened for beta-lactamase genes in a polymerase chain reaction. Three E. fergusonii isolates (CR11, CR35 and CR49) were obtained during this study. E. fergusonii strains were motile, non-lactose and non-sorbitol fermenting but positive for cellobiose and adonitol fermentation. The I6S rRNA assigned the phenotypically identified isolates to E. fergusonii species. All three isolates were multidrug-resistant, carbapenem-resistant and ESBL producers. Isolates CR11 and CR35 harboured cefotaximase (CTX-M) and temoniera (TEM) beta-lactamase genes while CR49 harboured sulfhydryl variable (SHV) beta-lactamase gene. We herein report the detection of multiple beta-lactamase genes in carbapenem-resistant ESBL producing E. fergusonii from clinical samples.

Distribution of Some Antibiotics Resistance Genes in Multi-drug Resistant E. coli Isolates from the Urogenitals of Women in Port Harcourt, Nigeria

Aim: The problem of antibiotics resistance has assumed a global emergency status. Whereas Multidrug Resistant (MDR) E. coli infection is common among human population in Port Harcourt metropolis of Nigeria, the genetic background of E. coli isolates in our locality is not well elucidated, hence this study.
 Study Design: This was a randomized study of women, with indications of Urogenital infections, attending Braithwaite Memorial Specialist Hospital (BMSH) Port Harcourt, Nigeria between July and December, 2017.
 Methodology: Ninety-Seven (97) samples comprising of urine, high vaginal swabs, end ocervical swabs were collected from patients to assess for the presence of some antibiotic resistance genes in multi-drug resistant E. coli. Samples were processed following standard microbiological protocols. Antimicrobial susceptibility test was performed on all E. coli isolates. Following this, all Multiple Drug Resistant E. coli were subjected to polymerase chain reaction (PCR) method for the detection of some antibiotic resistance-encoding genes- SHV, CTX-M, TEM. 
 Results: Seventy-three (73) isolates, including 36 E. coli, were recovered from all the clinical specimens. Twenty-four (24) E. coli isolates were found to be multi-drug resistant. Sulphydryl Variable (SHV) was the most frequent resistant gene and was detected in 15 isolates. This was followed by Cefotaximase (CTX-M) in 10 isolates and Temoniera (TEM) in 5 isolates. Some isolates haboured more than one resistance gene. About 20% of the isolates haboured SHV/CTX-M; 2.5% haboured CTX-M/TEM, while no target was detected in one isolate.
 Conclusion: This present study revealed that most E. coli isolates from the urogenitals of women within our locality, possess the ESBL genes which confers on them the Multidrug resistant status and this is a major challenge to maternal health.

Effect of β -lactamases associated to the resistance of β -lactam antibiotics on the treatment of wastewater

Antibiotics are drugs used on both animals and humans. However, when their residues or metabolites are released into the environment, it can cause microbial resistance in water bodies, including wastewater treatment plants. In this study, extended spectrum β-lactamases (ESBLs) were monitored in an anaerobic-aerobic combined biological treatment system. The enzymes Oxacillinase (OXA), Cefotaximases (CTX) and New Delhi metallo-β-lactamase (NDM-1) were added to the treatment and analyzed by qPCR (Quantitative Polymerase Chain Reaction) and plate count using a selective medium. Quantification of the effect of adding these enzymes was performed before, during and after they were added in order to establish the behavior of the treatment system under three different conditions. Anaerobic reactors proved more efficient at treating wastewater containing the β-lactamases OXA, CTX and NDM-1 than the ASP3 aerobic reactor that was working individually. However, an anaerobic-aerobic treatment train was much more effective at removing organic matter, even in the presence of β-lactamase.

Antimicrobial susceptibility, risk factors and prevalence of bla cefotaximase, temoneira, and sulfhydryl variable genes among Escherichia coli in community-acquired pediatric urinary tract infection.

INTRODUCTION:The emergence of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli has become an important challenge among pediatric patients with community-acquired urinary tract infection (UTI).OBJECTIVES:The aim of this study was to assess the antimicrobial susceptibility patterns, associated risk factors and to survey the frequency of bla cefotaximase (CTX-M), bla temoneira (TEM), and bla sulfhydryl variable (SHV) genotypes in ESBL-producing E. coli isolated from children with community-acquired UTI.METHODS:This was a prospective study conducted from November 2012 to March 2016 in a tertiary care center. E. coli isolated in urine cultures from children aged ≤18 years was identified and confirmed for ESBL production. ESBL-positive strains were screened for ESBL encoding genes. Chi-square test and Fisher's exact test were used to compare the difference in antibiotic susceptibility with respect to ESBL positive and negative, and binary logistic regression was used to identify the risk factors associated with ESBL production.RESULTS:Among 523 E. coli isolates, 196 (37.5%) were ESBL positive, >90% were resistant to cephalosporins, and 56% were resistant to fluoroquinolones. Least resistance was observed for imipenem, netilmicin, and nitrofurantoin (2%, 8.6%, 15.3%). Association between ESBL production and drug resistance was significant for ceftazidime (P < 0.001), cefixime (P < 0.001), cefotaxime (P = 0.010), ceftazidime-clavulanic acid (P < 0.001), levofloxacin (P = 0.037), and gentamicin (P = 0.047) compared to non-ESBL E. coli. CTX-M gene was the most prevalent (87.5%), followed by TEM (68.4%) and SHV (3.1%). Previous history of UTI and intake of antibiotics were the common risk factors.CONCLUSION:ESBL-producing E. coli from community-acquired pediatric UTI carries more than one type of beta-lactamase coding genes correlating their increased antibiotic resistance. Aggressive infection control policy, routine screening for detecting ESBL isolates in clinical samples, and antimicrobial stewardship are the keys to prevent their dissemination in community settings.

Phenotypic and molecular characterization of cefotaximases, temoniera, and sulfhydryl variable β-lactamases in Pseudomonas and Acinetobacter isolates in an Indian tertiary health-care center.

Cefotaximases (CTX-M), temoniera (TEM), and sulfhydryl variable (SHV) constitute a rapidly growing cluster of enzymes that have disseminated geographically. They are spreading to species other than Enterobacteriaceae and might be responsible for the presence of blaCTX-M,blaTEM, and blaSHVgenes in Pseudomonas and Acinetobacter spp. The present study was designed to characterize CTX-M, TEM, and SHV phenotypically and genotypically in Pseudomonas and Acinetobacter spp. A total of 90 isolates (73 Pseudomonas and 17 Acinetobacter spp.), resistant to any of the third-generation cephalosporins, were randomly selected from clinical samples. Of 90 isolates, 64 (71.11%) were tested positive for extended-spectrum β-lactamase (ESBL) production. Among phenotypically tested ESBL producers, forty isolates were randomly selected for molecular characterization. The prevalence of CTX-M, TEM, and SHV was found to be 57.5%, 15%, and 75%, respectively. Multiplex polymerase chain reaction assay categorized blaCTX-Mgenes into Groups 1 and 26 where Group 1 was present in only 5 isolates and Group 25 was present in rest of the 18 isolates. This is among the premier systemic reports from India documenting phenotypic and molecular characterization of CTX-M, TEM, and SHV β-lactamases in Pseudomonas and Acinetobacter spp. With judicious use of antibiotics and strict infection control procedures, it may be possible to limit the effects of these newer β-lactamases.

Detection of blaCTX-M Extended Spectrum Beta-lactamase Producing Salmonella enterica Serotype Typhi in a Tertiary Care Centre.

Infections caused by Salmonella are an important public health threat in tropical and subtropical countries. Due to the emergence of resistance to ampicillin, chloramphenicol and trimethoprim/sulfamethoxazole (multidrug resistant salmonellae) in the late 1980s, fluoroquinolones and extended spectrum cephalosporins became the drugs of choice. Resistance to cefotaxime and ceftriaxone due to the production of Extended Spectrum Beta-Lactamase (ESBL) and reduced susceptibility to ciprofloxacin have emerged resulting in treatment failure. The Cefotaximase (CTX-M) type ESBLs are the most widespread beta lactamase among Enterobacteriaceae including salmonellae. To detect the presence of blaCTX-M in salmonellae causing human infections. Detection of qnr genes to identify the coexistence of blaCTX-M and qnr gene. The study included 103 consecutive, non-repetitive salmonellae isolated from clinical specimens obtained from July 2015- June 2016 which were identified up to species level by conventional/automated methods. Susceptibility to various classes of antimicrobial agents was determined by disc diffusion method. Minimum Inhibitory Concentration (MIC) to cefotaxime and ceftriaxone was determined by agar dilution method. The results were interpreted in accordance with Clinical & Laboratory Standard Institute (CLSI) (guidelines 2015. Detection of the ESBL phenotype was performed by the combined disk method. Polymerase Chain Reaction (PCR) amplification of all isolates was performed using group specific primers to characterize the presence of blaCTX-M, qnrA, qnrB and qnrS. Of the 103 study isolates two isolates of Salmonella typhi were resistant to cefotaxime and ceftriaxone and had a MIC of 128μg/ml. PCR amplification and sequencing detected the presence of blaCTX-M-15 in these two isolates. These two isolates exhibited resistance to ciprofloxacin in vitro but qnr gene was not detected in these isolates. Resistance to third generation cephalosporins among salmonellae is a cause for concern as it may lead to treatment failure. It is imperative to continuously monitor the susceptibility pattern as enteric fever is endemic in India.

Fecal Colonization With Extended-spectrum Beta-lactamase-Producing Enterobacteriaceae and Risk Factors Among Healthy Individuals: A Systematic Review and Metaanalysis.

Gut colonization is a risk factor for infections with extended-spectrum beta-lactamase (ESBL)-producing organisms. We aimed to determine the ESBL class A reservoir among healthy individuals. We searched PubMed and EMBASE (through 10 July 2015) looking for studies that contained data for fecal colonization with ESBL class A bacteria among healthy individuals for each World Health Organization-defined region. Distribution of isolates among cefotaximase (CTX-M), sulfhydryl variable, and temoneira enzymes and data on previous antibiotic use, international travel, previous hospitalization, and animal contacts were extracted. Sixty-six of 17 479 studies on 28 909 healthy individuals were included. The pooled prevalence of ESBL class A colonization was 14% (95% confidence interval [CI], 9, 20), with an increasing trend of 5.38% annually (P = .003). The pooled prevalence was higher in Asia and Africa (ranging from 46%, 95% CI, 29, 63 to 15%, 95% CI, 4, 31) and lower but still significant in central (3%, 95% CI, 1, 5), northern (4%, 95% CI, 2, 6), and southern Europe (6%, 95% CI, 1, 12) and the Americas (2%, 95% CI, 0, 5). CTX-Ms were the prevalent ESBL enzyme (69%). Antibiotic use for the prior 4 or 12 months was associated with a high colonization risk (risk ratio [RR] = 1.63; 95% CI, 1.19, 2.24 and RR = 1.58; 95% CI, 1.16, 2.16, respectively). International travel was also correlated with ESBL colonization [(RR = 4.06, (95% CI, 1.33, 12.41)]. The ESBL colonization rate among healthy individuals is significant worldwide. This should be taken into consideration in infection control and antibiotic management decisions.

Evaluation of the Antibiotic Resistance and Virulence of Escherichia coli Strains Isolated from Chicken Carcasses in 2007 and 2013 from Paraná, Brazil

The frequent use of antimicrobials in commercial poultry production has raised concerns regarding the potential impact of antimicrobials on human health due to selection for resistant bacteria. Several studies have reported similarities between extraintestinal pathogenic Escherichia coli (ExPEC) strains isolated from birds and humans, indicating that these contaminant bacteria in poultry may be linked to human disease. The aim of our study was to analyze the frequency of antimicrobial resistance and virulence factors among E. coli strains isolated from commercial chicken carcasses in Paraná, Brazil, in 2007 and 2013. A total of 84 E. coli strains were isolated from chicken carcasses in 2007, and 121 E. coli strains were isolated in 2013. Polymerase chain reaction was used to detect virulence genes (hlyF, iss, ompT, iron, and iutA) and to determine phylogenetic classification. Antimicrobial susceptibility testing was performed using 15 antimicrobials. The strains were also confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli with phenotypic and genotypic tests. The results indicated that our strains harbored virulence genes characteristic of ExPEC, with the iutA gene being the most prevalent. The phylogenetic groups D and B1 were the most prevalent among the strains isolated in 2007 and 2013, respectively. There was an increase in the frequency of resistance to a majority of antimicrobials tested. An important finding in this study was the large number of ESBL-producing E. coli strains isolated from chicken carcasses in 2013, primarily for the group 2 cefotaximase (CTX-M) enzyme. ESBL production confers broad-spectrum resistance and is a health risk because ESBL genes are transferable from food-producing animals to humans via poultry meat. These findings suggest that our strains harbored virulence and resistance genes, which are often associated with plasmids that can facilitate their transmission between bacteria derived from different hosts, suggesting zoonotic risks.

A longitudinal field trial assesing the impact of feeding waste milk containing antibiotic residues on the prevalence of ESBL-producing Escherichia coli in calves

A longitudinal field trial was carried out on a farm known to harbour cefotaximase (CTX-M)-positive Escherichia coli, in order to assess the impact of feeding waste milk containing antibiotic residues (WM+AR) on the prevalence of these bacteria in the faeces of calves. Fifty calves were alternately assigned to one of two groups at birth and fed either milk replacer (control group) or WM+AR (treatment group). Faecal samples were collected from all calves daily for the first week after enrolment, twice weekly until weaning, then weekly for a further six weeks. Environmental samples from the calf housing were collected weekly. WM+AR and powdered milk samples were examined for antibiotic residues and CTX-M-positive E. coli. Total E. coli and CTX-M-positive E. coli in faecal samples were enumerated using selective media. Regression analyses were performed on the bacterial count data using a population-averaged approach based on generalised estimating equations (GEE) to account for repeated measurements on individual calves over time.Cefquinome, a fourth generation cephalosporin, was detected in 87% of WM+AR samples at a mean concentration of 0.746mg/l. All environmental sampling locations yielded CTX-M-positive E. coli. Significantly more pen floor samples were positive in the treatment group. Calves in the treatment group shed greater numbers of CTX-M-positive E. coli than calves in the control group throughout the study, and shedding decreased at a slower rate in the treatment group. CTX-M-positive E. coli persisted in a larger number of calves fed WM+AR compared with calves fed milk replacer where the prevalence in the treatment group declined significantly slower over time. There was no difference between calves fed WM+AR or calves fed milk replacer in the proportion of E. coli isolates that were CTX-M-positive.These findings indicate that feeding WM+AR increased the amount of resistant bacteria shed in the faeces. Shedding of CTX-M-positive E. coli persisted for longer in calves fed WM+AR, and persisted after weaning.

Genetic and phenotypic characterisation of Escherichia coli producing cefotaximase-type extended-spectrum β-lactamases: first evidence of the ST131 clone in cats with urinary infections in Italy.

The incidence of cefotaximase (CTX-M)-type extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has increased dramatically in humans and animals since the middle of the last century. E coli that produce CTX-M β-lactamase represent a major cause of urinary tract infections, and pose a significant therapeutic challenge to both human and veterinary medicine. As data on uropathogenic CTX-M-producing strains in cats are limited, the aim of this study was to describe the genetic character and antibiotic resistance phenotypes of CTX-M-producing E coli isolated from cats with cystitis. Seven of 15 E coli bacteria isolated from 138 urine samples had the CTX-M gene and were therefore included in this study. These isolates were screened by polymerase chain reaction for the presence of 14 extra-intestinal virulence factors, class 1 and class 2 integrons, and to identify their phylogenetic groups. Multi-locus sequence typing (MLST) of the strains and susceptibility testing (disc diffusion method) were also performed. Virulence factor iutA was the most frequent determinant identified (86.7%), and the majority of CTX-M-producing strains (n = 5) carried class 1 integrons. MLST allowed us to discriminate four known sequence types (ST131, ST555, ST602, ST155) and three novel sequence types (ST3847, ST3848, ST4181). To the best of our knowledge, this is the first study to report uropathogenic CTX-M-producing E coli ST131 in cats in Italy. Accurate diagnostics and prudent use of antimicrobials are recommended to avoid the spread of multidrug-resistant pathogens in veterinary medicine and to prevent their transmission to humans.

Molecular characterization of extended spectrum β-lactamase (ESBL) producing Shigella species isolated from patients with bacillary dysentery in Iraq

Background: Extended-spectrum β-lactamases (ESBLs), including cefotaximases (CTX-M), mediate resistance to extended spectrum cephalosporins and significantly compromise the treatment tools for Shigellosis.&#x0D; Objective: To determine the ESBLs production by Shigella spp. and its role in the resistance to third generation cephalosporins and to determine the occurrence of plasmid- borne blaCTX genes in ESBLS Shigella isolates by Multiplex PCR.&#x0D; Methods: Susceptibility of 59 clinical Shigella isolates was tested by disk diffusion method to six antimicrobial agents. Presence of ESBLs was established by the combination disk method. Minimum inhibitory concentration of β-lactams was determined by agar dilution method for resistant isolates, and then ESBL producers were subjected to plasmid extraction and PCR experiments.&#x0D; Results: Overall isolates had high rate of resistance to Ampicillin (84.7%), Tetracycline (84.7%), Co-trimoxazole(72.9%) and Cefotaxime(69.5%). Moderate to Ceftriaxone (52.5%) and low rate of resistance to Ceftazidime(30.5%). The MIC value of resistant isolates of S. sonnei and S. flexneri for CTX and CRO ranged from (64-512 μg/ml) for both, and (32-256 μg/ml) for CAZ, whereas S. dysenteriae exhibit only high level resistance MIC (256 μg/ml) for CTX, low level resistance (64 μg/ml) for CRO and complete susceptibility to CAZ. 31 of 41 (75.6 %) of Shigella spp. were β-lactamase producers, of these (82.6%) were S. flexneri, (68.8%) S. sonnei, and one S. dysenteriae isolate. The results of PCR amplification of bla CTX gene groups showed that blaCTX-M genes were identified in (74.19%) ESBLs isolates distributed as 14(45.16%) S.flexneri isolates, 9(29.03%) S. sonnei, while no gene was detected in ESBLs S. dysenteriae isolate. The prevalence of bla CTX-M I, bla CTX-M II (TOHO 1) and blaCTX-M III, were ( 54.8%, 16.1% and 3.2% ) respectively. Non of the isolates carried more than one type.&#x0D; Conclusion: The occurrence of plasmid- borne blaCTX genes in ESBLS Shigella isolates are increasing in Iraq with co-resistance to some other classes of antibiotics

Outbreak of Shiga Toxin-Producing Escherichia coli O104:H4 Associated With Organic Fenugreek Sprouts, France, June 2011

On 22 June 2011, 8 patients with hemolytic uremic syndrome (HUS) or bloody diarrhea were reported in France. All 8 were attendees of a community center event on 8 June near Bordeaux. Three Escherichia coli cases were confirmed by isolation of Shiga toxin-producing E. coli O104:H4 stx2 aggR producing a cefotaximase (CTX-M) β-lactamase (STEC O104:H4); the same rare serotype caused the outbreak in Germany in May-July 2011. An investigation was initiated to describe the outbreak, identify the vehicle for infection, and guide control measures. We conducted a retrospective cohort study among all adults attending the event, including food handlers. A standardized questionnaire was administered to participants. A case was an attendee who developed HUS or diarrhea between 8 and 24 June. Cases were confirmed by isolation of STEC O104:H4 or O104 serology. Relative risks (RRs) and 95% confidence intervals (CIs) by exposure were calculated using a Poisson regression model. Twenty-four cases were identified (14% attack rate). Of these, 18 (75%) were women, 22 (92%) were adults, 7 (29%) developed HUS, 5 (21%) developed bloody diarrhea, and 12 (50%) developed diarrhea. Ten (42%) cases were confirmed. Fenugreek was the only sprout type with an independent association to illness (RR, 5.1; 95% CI, 2.3-11.1) in multivariable analysis. This investigation identified a point-source STEC O104:H4 outbreak associated with consumption of fenugreek sprouts. Comparison of results from French and German STEC O104:H4 outbreak investigations enabled identification of a common food vehicle, fenugreek sprouts, and resulted in implementation of Europe-wide control measures in July 2011.

Plasmid-Mediated Quinolone Resistance Genes in &lt;i&gt;Escherichia coli&lt;/i&gt; Urinary Isolates from Two Teaching Hospitals in Turkey: Coexistence of TEM, SHV, CTX-M and VEB-1 Type &amp;#946-lactamases

Purpose: To evaluate the occurrence of plasmid-mediated quinolone resistance (PMQR) genes and the prevalence of extended spectrum &#946-lactamase (ESBL) types in Escherichia coli clinical isolates. Methods: Sixty-one ESBL-producing urinary E. coli isolates were studied. An antibiotic susceptibility test was performed using the disc diffusion method. ESBL production was determined using a double-disc synergy test for all isolates; E-test and Vitek 2 were used for plasmid-mediated quinolone resistance (PMQR)-positive isolates and their transconjugants. The presence of PMQR and &#946-lactamase genes was determined by polymerase chain reaction (PCR). Results: The strains displayed high rates of resistance to norfloxacin (80 %). The most frequent PMQR gene was aac(6’)-Ib-cr (45.9 %). In all, one qnrA1 (1.6 %), one qnrS1 (1.6 %), and two qepA1-positive isolates (5.7 %) were identified. The genes, qnrS1+aac(6’)-Ib-cr and qepA1, were co-expressed with blaCTX-M-15 gene, while qnrA1 occurred with blaTEM-1, blaSHV, and blaVEB-1 genes. The most frequent &#946-lactamase type was cefotaximase (CTX-M), which generally hydrolyzes cefotaxime (92 %) more than it does ceftazidime; followed by temoneira (TEM, 39 %); sulfhydryl variable (SHV, 5 %), and Vietnamese extended-spectrum beta–lactamase (VEB, 1.6 %). Conclusion: A high prevalence of aac(6’)-Ib-cr and CTX-M type &#946-lactamase was detected in ESBLproducing E. coli strains. This study also identified the co-expression of qnrA1 and blaVEB-1 genes and of qnrS1+aac(6’)-Ib-cr in E. coli isolates. The co-existence of PMQR genes with ESBLs may lead to a serious public health problem. Keywords: &#946-lactamase, Quinolone resistance, aac(6’)-Ib-cr, CTX-M-15, VEB-1

Identification and Characterization of CTX-M-Producing Shigella Isolates in the United States

Shigellosis is a major source of gastroenteritis throughout the world (14). Extended-spectrum β-lactamases (ESBLs), including cefotaximases (CTX-M), confer resistance to extended-spectrum cephalosporins and significantly compromise the treatment options for shigellosis. Numerous ESBLs have been described among Enterobacteriaceae (2, 8, 13); however, only a single CTX-M-producing Shigella isolate has been reported in the United States (10). From 1999 to 2007, 3,880 Shigella isolates were screened for antimicrobial susceptibility to 14 to 17 antimicrobials by broth microdilution (Sensititre; Trek Diagnostics, Westlake, OH). Six isolates displayed decreased susceptibility (MIC ≥ 2 mg/liter) to ceftriaxone (Table ​(Table1).1). The six case-patients included three males and two females (gender information was unavailable for one patient), and the median age was 3 years (range, 1 to 8 years). Additional details were available for five patients. Three of the five (60%) were hospitalized, and one was admitted twice. One patient had an adopted sibling from Russia but had not traveled herself. The second patient traveled to a neighboring state prior to illness onset, and the third reported no travel. Of the nonhospitalized patients, one was an asymptomatic adoptee from China and the second reported no travel. Two patients received antimicrobial therapy: ceftriaxone, cefotaxime, and trimethoprim-sulfamethoxazole for one patient, azithromycin for the other patient. TABLE 1. Characterization of CTX-M-positive Shigella isolates, transformants, and CTX-M-encoding plasmidsa PCR analysis was used to screen the six isolates for 13 different classes or groups of bla genes, and PCR results were confirmed by DNA sequencing (1, 5, 11, 12, 16, 18-21). Four isolates were positive for the blaCTX-M-15 gene, while two were positive for the blaCTX-M-14 gene (Table ​(Table1).1). All four blaCTX-M-15 isolates were PCR positive for non-ESBL blaTEM-1 genes. Both blaCTX-M-14 isolates were PCR positive for non-ESBL blaOXA-1 genes, and a single isolate was positive for both blaTEM-1 and blaOXA-1. By pulsed-field gel electrophoresis (PFGE) analysis, all three S. sonnei and all three S. flexneri isolates demonstrated distinct patterns (data not shown) (15). All six blaCTX-M genes were determined to be plasmid encoded (6). The non-ESBL β-lactamases (OXA-1, TEM-1) did not transfer and were not encoded on the same CTX-M plasmids. All three S. sonnei plasmids and two of the S. flexneri plasmids harbored only the CTX-M-associated resistance. The remaining S. flexneri plasmid contained additional determinants conferring resistance to trimethoprim-sulfamethoxazole and gentamicin. All three S. sonnei plasmids were incompatibility type IncI1 and approximately 90 kb in size (plasmid pulsed-field gel electrophoresis) (Table ​(Table1)1) (4). Plasmid multilocus sequence typing (pMLST) identified them as novel sequence types designated as ST31 complex. The plasmid from AM22451 contained several point mutations in one allele, necessitating the ST32 designation within the ST31 clonal complex (http://pubmlst.org/plasmid) (7). Of the three S. flexneri plasmids, the blaCTX-M-15-positive plasmid was a 165-kb IncA/C plasmid, while the two blaCTX-M-14-positive plasmids were identical 75-kb IncFII plasmids. CTX-M-14 and CTX-M-15 are the most common types of cefotaximases identified among Shigella isolates (9, 17, 22), and IncI1 plasmids carrying CTX-M-15 have been already described in Escherichia coli and Salmonella isolates from Australia, France, and the United Kingdom (3). The emergence of CTX-M-producing Shigella isolates in the United States is concerning and necessitates continued resistance surveillance.