Extended-spectrum Beta-lactamase Enzymes Research Articles

Faropenem resistance causes in vitro cross-resistance to carbapenems in ESBL-producing Escherichia coli

ObjectiveFaropenem is an oral penem drug with activity against Gram-positive and Gram-negative bacteria, including CTX-M-15-type extended spectrum beta-lactamase (ESBL)-producing Enterobacteriales and anaerobic bacteria. As there are structural similarities, there is concern for the development of carbapenem cross-resistance; however, there are no studies confirming this. This study examined whether in vitro development of faropenem resistance in Escherichia coli isolates would result in cross-resistance to carbapenems. MethodsFour well-characterized E. coli isolates from the US Centers for Disease Control and Prevention antibiotic resistance isolate bank were utilized. Three isolates (NSF1, NSF2 and NSF3) are ESBL producers (CTX-M-15) and one (NSF4) is pan-susceptible. Faropenem minimum inhibitory concentrations (MICs) were determined and resistance was induced by serial passaging in increasing concentrations of faropenem. Susceptibility to carbapenems was determined and whole-genome sequencing (WGS) was performed to identify the underlying genetic mechanism leading to carbapenem resistance. ResultsFaropenem MIC increased from 1 mg/L to 64 mg/L within 10 days for NSF2 and NSF4 isolates, and from 2 mg/L to 64 mg/L within 7 days for NSF1 and NSF3 isolates. Reduced carbapenem susceptibility (ertapenem MIC ≥8 mg/L, doripenem/meropenem ≥2 mg/L and imipenem ≥1 mg/L) developed among three CTX-M-15-producing isolates that were faropenem-resistant, but not in NSF4 isolate that lacked ESBL enzyme. WGS analysis revealed non-synonymous changes in the ompC gene among three CTX-M-15-producing isolates, and a single nucleotide polymorphism (SNP) in the envZ gene in NSF4 isolate. ConclusionInduced resistance to faropenem causes cross-resistance to carbapenems among E. coli isolates containing CTX-M-15-type ESBL enzymes.

Extended-Spectrum Beta-Lactamase Enzyme (ESBL) Production from Antimicrobial-Resistant Escherichia coli Isolates and their Attachment on Stainless-Steel Surface

Food contact surfaces may pose a threat of becoming vector for antimicrobial-resistant transmission of bacteria along the food chain. Twenty-four isolates of Escherichia coli were investigated to determine the antimicrobial resistance, production of Extended-Spectrum Beta-Lactamase Enzyme and their attachment ability on stainless-steel surface. The antimicrobial resistance and enzyme production tests were carried out according to standard disc diffusion assay, while attachment was simulated on stainless steel discs. All 24 isolates were resistant to Amoxycillin and Penicillin, while 50% and 37.5% were resistant to Ceftriaxone and Cefotaxime, respectively. Three of 24 isolates (12.5%) produced the enzyme against cefotaxime, ceftazidime and ceftriaxone. The enzyme production was further confirmed by the expansion of cefotaxime, ceftriaxone and ceftazidime inhibition zone towards amoxicillin-clavulanate disc. All 3 enzyme-producing isolates (EC-6, EC-7 and EC-12) exhibited their ability to attach to stainless-steel disc. Attachment was significantly increased (p<0.05) with prolonged incubation times with the highest attachment (6.07±0.05 log10 cfu/ml) by isolate EC-6 at 72h. The attachment ability indicates that resistant E. coli can be potentially transmitted into the food chain via contaminated food contact surfaces. Our data could be used to develop research to link the spread of antimicrobial resistance towards effective intervention strategies.

In Vitro Inhibitory Activity of Dayak Onion (Eleutherine bulbosa Mill.) Essential Oil Against Klebsiella pneumoniae

Background: The cases of Klebsiella pneumoniae infection in West Java province is still high. Klebsiella pneumoniae bacterium can produce the Extended Spectrum Beta Lactamase enzyme leading to antibiotics resistant, so it is important to look for natural and inexpensive an􀦞bio􀦞c alternatives; one of which is Dayak onion plant (Eleutherine bulbosa Mill). The content found in Dayak onion is believed to inhibit the growth of Klebsiella pneumoniae bacteria. This study aims to determine the effectiveness of Dayak onion essential oil on the growth of Klebsiella pneumoniae bacteria. Methods: This study was an experimental study with a post-test control group design using the culture of Klebsiella pneumoniae on the media Muller Hinton Agar in 7 groups. Groups 1 to 5 (K1 to K5) were given sequentially Dayak Onion essential oil solution in 10% DMSO solvent with concentrations of 50%, 25%, 12.5%, 6.25%, and 3.125%. Group 6 (K6) was positive control (+) with 5 μg Levofloxacin, and Group 7 (K7) was Negative (-) with 10% DMSO. The treatment results were measured by the diameter of the host zone and the collected data were analyzed using One-way ANOVA with appropriate Post hoc analysis. Results: The results showed that that there are differences in each group to inhibit the growth of bacteria (p <0.005). K1 are higher than K2, K3, K4, K5, and K7 with increasing concentrations showed greater inhibi􀦞on. Levofloxacin (K6) showed the highest inhibitory power. Conclusion: The results showed that that there are differences in each group to inhibit the growth of bacteria (p <0.005). K1 are higher than K2, K3, K4, K5, and K7 with increasing concentrations showed greater inhibition. Levofloxacin (K6) showed the highest inhibitory power. Keywords: Klebsiella pneumoniae, Dayak onion essential oil, bacterial inhibition Received: 26 April 2019 Reviewed: 15 June 2019 Revised: 1 July 2019 Accepted: 12 July 2019 DOI: 10.35898/ghmj-33587

In Vitro Inhibitory Activity of Dayak Onion (Eleutherine bulbosa Mill.) Essential Oil Against Klebsiella pneumoniae

Background: The cases of Klebsiella pneumoniae infec on in West Java province is s ll high. Klebsiella pneu- moniae bacterium can produce the Extended Spectrum Beta Lactamase enzyme leading to an bio cs resistant, so it is important to look for natural and inexpensive an bio c alterna ves; one of which is Dayak onion plant (Eleutherine bulbosa Mill). The content found in Dayak onion is believed to inhibit the growth of Klebsiella pneu- moniae bacteria. This study aims to determine the effec veness of Dayak onion essen al oil on the growth of Klebsiella pneumoniae bacteria. Methods: This study was an experimental study with a post-test control group design using the culture of Kleb- siella pneumoniae on the media Muller Hinton Agar in 7 groups. Groups 1 to 5 (K1 to K5) were given sequen ally Dayak Onion essen al oil solu on in 10% DMSO solvent with concentra ons of 50%, 25%, 12.5%, 6.25%, and 3.125%. Group 6 (K6) was posi ve control (+) with 5 μg Levofloxacin, and Group 7 (K7) was Nega ve (-) with 10% DMSO. The treatment results were measured by the diameter of the host zone and the collected data were analyzed using One-way ANOVA with appropriate Post hoc analysis. Results: The results showed that that there are differences in each group to inhibit the growth of bacteria (p <0.005). K1 are higher than K2, K3, K4, K5, and K7 with increasing concentra ons showed greater inhibi on. Levofloxacin (K6) showed the highest inhibitory power. Conclusion: The results showed that that there are differences in each group to inhibit the growth of bacteria (p <0.005). K1 are higher than K2, K3, K4, K5, and K7 with increasing concentra ons showed greater inhibi on. Levofloxacin (K6) showed the highest inhibitory power.

Isolation of multidrug resistant bacterium in urban wildlife. What is in your backyard?

Animal and human interaction encourage zoonotic transmission of microbes resulting in colonization and risk for infectious disease. Studies of individuals working in agriculture show increased cases of Salmonella infection along with a higher colonization of antimicrobial resistant microbes. However risk from wildlife exposure is not fully understood. Alaska’s largest city, Anchorage, is home to approximately one thousand moose migrating into city parks and suburban backyards. Environmental impact of moose fecal contamination could prove to be a public health risk. From November 2018 through February 2019, we collected forty moose fecal samples surveying the Anchorage, Mat-Su Valley region. Utilizing standard microbial techniques isolated bacterium were identified, along with antimicrobial susceptibility testing, using MicroScan™ conventional panels. Colistin resistance on Escherichia coli and phenotypic evaluation for extended spectrum beta-lactamase enzyme in Enterobacteriacea were performed using disc diffusion. Multidrug resistant (MDR) organisms were isolated in 39% of moose fecal samples with 100% containing colistin resistant Escherichia coli. MDR gram negative bacilli identified included Acinetobacter baumanii/haemolyticus, Ewingella americana, Klebsiella ascorbate, Klebsiella ozaenae, Leminorella grimotti, and Pantoea agglomerans. Additionally, Klebsiella isolates expressed phenotypic extended spectrum beta-lactamase enzyme (ESBL). Antibiotic resistant gram positive organisms included methicillin resistant Staphylococcus aureus (MRSA) and linezolid resistant, vancomycin resistant Enterococcus fecalis (VRE). Close proximity of moose in our urban Alaska environment draws attention to their commensal microbiome and potential for infectious transfer to humans. We discovered nearly 40% of moose fecal samples contained one or more multidrug resistant bacterium with several organisms currently identified as a healthcare risk including MRSA, VRE and ESBL producing Klebsiella species. Wildlife exposure to urban landscape, including antibiotic contaminated water, could provide an additional avenue for development of antimicrobial resistant organisms. Further study is indicated to determine potential public health risk of wildlife zoonotic transfer of existing and novel multidrug resistant bacteria.

Plasmid Profile Analysis of Pseudomonas aeruginosa Isolated from Wound Infections in a General Hospital in Southern Nigeria

Background/Purpose: Open wound infection is a serious problem especially with extended-spectrum beta lactamase (ESBL) producing Gram negative bacteria such as P. aeruginosa. The purpose of this research was to identify open wound infections due to Pseudomonas aeruginosa and also determine their plasmid profile.
 Methods: A total of 50 Pseudomonas aeruginosa isolates were obtained from clinical wound swabs in a secondary health care facility. Pseudomonas aeruginosa isolates were identified using Microbact 24E system kit. Pseudomonas aeruginosa were isolated and subjected to antibiotic susceptibility testing by disc diffusion method. ESBL production was detected using Double Disk Synergy Test (DDST) and CHROMagar ESBL (France). Six different antibiotic discs were used to determine the susceptibility pattern of the isolates. Plasmids were extracted using ZR plasmid Miniprep classic extraction Kit. Electrophoresis of the DNA was carried out on 0.8% w/v agarose gel.
 Results: The prevalence of Pseudomonas aeruginosa was 63%. The antibiotic resistance pattern showed that Pseudomonas aeruginosa was highly resistant against cefotaxime (90%), ofloxacin (80%), ceftazidime (55%), azetronam (60%), imipenem (25%), amoxicillin clavulanic acid (35%) and amikacin (30%). Plasmid profile was carried out on 20 selected multidrug resistant isolates; those resistant to three or more classes of antibiotics. Plasmid content of the isolates were found to be 90%. All isolates that had plasmid were resistant to cefotaxim, ceftazidime, azetronam, ofloxacin and amikacin.
 Conclusion: Antibiotic resistance by P. aeruginosa is increasingly high in wound infections and appears to be linked to the presence of plasmid and ESBL enzymes.

The accuracy of extended-spectrum beta-lactamase detection in Escherichia coli and Klebsiella pneumoniae in South African laboratories using the Vitek 2 Gram-negative susceptibility card AST-N255.

BackgroundPhenotypic detection of extended-spectrum beta-lactamases (ESBLs) is based on the inhibition of ESBL enzymes by β-lactamase inhibitors and on the comparison of cephalosporin activity with or without a β-lactamase inhibitor. Many South African diagnostic laboratories rely on the Vitek 2 for automated susceptibility testing and for ESBL detection. However, the Gram-negative susceptibility card currently used locally (AST-N255) has been modified and its accuracy for ESBL detection is not known.MethodsWe randomly selected 50 isolates of Klebsiella pneumoniae and Escherichia coli from a collection of clinical bloodstream isolates from Groote Schuur Hospital from 2015 to 2016, including ESBL-producing and non-ESBL-producing strains. We used standardised phenotypic (disc diffusion and broth microdilution) and genotypic (conventional polymerase chain reaction (PCR) for blaCTX-M, blaSHV and blaTEM) methods for detection of ESBLs. We compared ESBL detection by Vitek 2 to a composite reference standard comprising ESBL detection either by both phenotypic methods or by one phenotypic method together with genotypic detection.ResultsThe sensitivity of Vitek 2 system for detection of ESBLs was 33/36 or 92% (78% – 97%) for E. coli, and 40/40 or 100% (91% – 100%) for K. pneumoniae, whilst specificity was 10/10 or 100% (72% – 100%) and 9/10 or 90% (60% – 98%), respectively. This is comparable with previous studies.ConclusionUsing a composite reference standard of the phenotypic and genotypic methods employed in this study, no Vitek-categorised ESBL E. coli or K. pneumoniae was found to be a non-ESBL with the exception of possible misinterpretation with K. pneumoniae SHV-hyper-producing isolates.

Detection of extended-spectrum beta-lactamases in Pseudomonas aeruginosa and Acinetobacter baumanniiand their prevalence in Intensive care unit of a tertiary care hospital

Introduction: Pseudomonas aeruginosa and Acinetobacter baumannii have been known to cause variety of infections, among patients admitted in Intensive Care Unit.Non fermenting Gram‑negative bacilli are developing resistance to commonly used antibiotics therefore are becoming difficult to treat Among various enzymes produced by bacteria which lead to drug resistance, extended‑spectrumbeta‑lactamase (ESBL) enzymesis one of the important mechanism of drug resistance. Thisstudy that was conducted a) To detect multidrug-resistant P. aeruginosa and A. baumanniiin patients admitted in ICU patients. b) To determine the prevalence of ESBL producing clinical isolates of Pseudomonas aeruginosa and Acinetobacter sp. in the ICU of the tertiary care hospital. Material and Methods: The study was performed in the microbiology department of a North Indian rural tertiary care hospital (Sri Guru Ram Das Institute of Medical Sciences and Research, Amritsar, India) over a period of one year (January2012 to December 2012). The study included 100 isolates each of Acinetobacter baumannii & P. aeruginosa. Identification of both organisms was done using the standard microbiological techniques as described by Colle et al 1996.The antimicrobial susceptibility testing was performed by Kirby Bauer disc diffusion method. To detect ESBL producing isolates phenotypicaly, Disc approximation test was performed. Results: Out of 200 isolates, 100 each of A. baumannii and P. aeruginosa, weobtained 82 isolates from ICU,57 &25 A .baumannii and P. aeruginosa respectively. Among these 57A. baumannii isolates 89.47%isolates were resistant to Ceftazidime and among these 33.33%isolates were ESBL producers.Of 25 P.aeruginosa isolatesobtained from ICU84 % were found to beresistant to ceftazidime by antibiotic sensitivity testing.Among these44% were ESBL producers. Conclusion: Our results showed high prevalence ofNon fermenting gram negative bacilli in ICU patient’s samples, which were multidrug resistant and producers of Extended spectrum Beta lactamase enzymes.

Frequency and Susceptibility Pattern of Extended Spectrum Beta Lactamase Producing Aerobic Gram Negative Bacteria in Post-Operative Infections

Extended spectrum β-lactamases occur commonly in the aerobic Gram negative bacteria (AGNB) such as <i>E. coli</i>, <i>Klebsiella</i> spp., <i>Proteus</i> spp., <i>Pseudomonas aeruginosa</i>, <i>Acinetobacter</i> spp., etc. and have the ability to make these organisms resistant to cephalosporins (e.g. ceftazidime, ceftriaxone, cefotaxime etc.), penicillins, and monobactams, i.e. aztreonam. However theses antibiotics become sensitive in the presence of clavulanic acid, an extended spectrum beta-lactamase (ESBL) inhibitor. ESBL enzymes do not influence cephamycins or carbapenems, i.e. meropenem, imipenem, etc. Major problems in surgery is wound infections after operations. High risks of wound infections are due to being immune-comprised on antibiotics, prolonged hospitalization and other factors in many cases. The current research determined various aerobic gram negative bacteria in post-operative wound infections at the College of Medical Laboratory Technology, the National Institute of Health, Islamabad, Pakistan. It also determined the frequency of ESBL in the organisms and established their susceptibility profile during the time period of the research. Infections caused by ESBL producers are a major problem in our post-operative patients. The commonest isolate was <i>E. coli</i> and the commonest ESBL producer was <i>Klebsiella</i> spp. Double disk synergy test is an effective method for screening of such isolates, and the practice of incorporating this test along with the routine sensitivity is recommended.

Antimicrobial Usages and Antimicrobial Resistance in Commensal Escherichia coli From Veal Calves in France: Evolution During the Fattening Process.

Extended-Spectrum-Cephalosporin (ESC)-resistant Enterobacteriaceae have widely spread in all settings worldwide. In animals, Extended-Spectrum Beta-Lactamase (ESBL) producers have been frequently identified in veal calves. The objectives of this study were to investigate the trends in the ESBL load and antimicrobial resistance (AMR) proportions, and antimicrobial usages (AMU) in veal calves during the fattening process. Ten fattening farms were selected and 50 animals per farm were sampled. AMR was assessed in bacteria from the dominant flora (collected on non-selective MacConckey agar) and in ESBL/AmpC-carrying bacteria from the subdominant flora (selected on ChromID ESBL selective plates) upon arrival and 5–6 months later before slaughter. The number and types of treatments during fattening were also collected. Rates of ESBL-producing E. coli from the subdominant flora significantly decreased in all farms (arrival: 67.7%; departure: 20.4%) whereas rates of multidrug-resistant E. coli from the dominant flora have significantly increased (arrival: 60.2%; departure: 67.2%; p = 0.025). CTX-M-1 was the most frequently identified ESBL enzyme (arrival: 59.3%; departure: 52.0%). The plasmid-mediated mcr-1 gene was also identified occasionally. In parallel, levels of resistances to non-critically important antimicrobials were already high upon arrival but have still further increased over time until slaughter. Our study also highlighted that if only ESBL-producing isolates were monitored, it might have led to a partial (and partly false) picture of AMR rates globally decreasing during the fattening period. The mean number of antimicrobial treatments per calf (NTPC) was 8.75 but no association between AMU and AMR was evidenced. Most ESBL producers were clonally unrelated suggesting multiple sources and not cross-contaminations among calves during transportation. Feeding milk containing antimicrobial residues to veal calves is hypothesized to explain the high ESBL loads in animals at the entrance on farms.

Isolation of CTX-M1, CTX-M2, CTX-M3 Genes Producing Extended-Spectrum Beta-Lactamase in Clinical Samples of Salmonella typhimurium

Objectives: The purpose of this study was to isolate CTX-M1 and CTX-M3 genes producing extended-spectrum beta-lactamase (ESBL) from clinical samples of Salmonella typhimurium isolated from poultry in Zabol, Iran. Methods: All the strains were cultured and identified in a clinical microbiology laboratory and were recovered from blood and urine cultures. The in vitro presence of ESBL was confirmed with Clinical and Laboratory Standard Institute double disc and PCR methods for CTX-M1 and CTX-M3. Results: The results of this study showed that Salmonella typhimurium samples were resistant to ampicillin (41.66%), gentamycin (0%), cefazolin (0%), amoxi-clav (10%), and azithromycin (5%) antibiotics. Conclusions: The widespread use of ESBL antibiotics has increased the spread of ESBL enzymes in Iran and throughout the world and the use of these antibiotics is becoming more and more limited. Therefore, the complete identification of ESBL by experiments, the restriction of the use of beta-lactam antibiotics and the use of beta-lactamase inhibitors can maintain the efficacy of beta-lactam antibiotics as much as possible.

Prevalence of extended-spectrum beta-lactamase genes in Acinetobacter baumannii strains isolated from nosocomial infections in Tehran, Iran.

Background and objectives: blaSHV, blaTEM and blaVEB are a group of Extended-Spectrum Beta-Lactamase enzymes (ESBLs) which are able to hydrolyze Penicillins and some cephalosporin antibiotics. The present study evaluated the frequency of ESBL genes blaSHV, blaTEM and blaVEB in Acinetobacter baumannii strains isolated from nosocomial infections to outline the importance of these genes in antibiotic resistance.Methods: One hundred Acinetobacter baumannii strains were isolated from different nosocomial infections. After antibiotic resistance evaluation with the Kirby-Bauer disc-diffusion method, the Minimum Inhibitory Concentration (MIC) of Ciprofloxacin was measured using the E-test method. Then, the ESBL producing strains were identified employing Combined Disk Methods. Finally, all isolates were evaluated with the Polymerase Chain Reaction (PCR) technique to detect the ESBL genes of interest.Results: Out of 100 Acinetobacter baumannii isolates, 59% were ESBL positive according to the phenotypic method. The PCR assay could not detect the blaSHV and blaVEB genes in the studied isolates, but the presence of blaTEM gene was demonstrated in 42% of the strains.Conclusion: The high resistance to most antibiotics, the high prevalence of ESBLs-producing strains and also a high prevalence of blaTEM gene in A. baumannii strains found in the current study gives cause for major concern about nosocomial infections in Iran because of the treatment complexity of these strains. Our results highlight the need for infection control measures to prevent the spread of resistant isolates, especially in hospitals.

Detection of the Presence of Extended-Spectrum Beta-Lactamase Enzyme in Gram-negative Bacteria According to CLSI and EUCAST Criteria

Detection of the Presence of Extended-Spectrum Beta-Lactamase Enzyme in Gram-negative Bacteria According to CLSI and EUCAST Criteria

Identification and Antibiotic Susceptibility Testing of ESBL producing Klebsiella strains by Phenotypic methods

Multi drug resistance has now become a worldwide therapeutic challenge due to the widespread use of broad spectrum antibiotics. Klebsiella species have significant importance in clinical field as they cause various infections in human and are considered as potential pathogens that express antibiotic resistance through their strong enzymatic activity. Extended spectrum beta lactamases (ESBLs) are plasmid mediated enzymes produced mostly because of mutation and few other factors. These enzymes confer resistance against various β-lactam drugs including cephalosporins and monobactams. Among the genus Klebsiella, ESBLs are highly prevalent in K. pneumoniae followed by K. oxytoca.&#x0D; This study was conducted in Pakistan to assess the distribution of ESBL producers among Klebsiella spp., an important member of the family Enterobacteriaceae. From January 2010 to January 2012, a total of 236 gram-negative isolates were collected from different renowned microbiological laboratories. Out of the 236 gram-negative isolates, 125 were found as Klebsiella spp. by using standard microbiological techniques. Antimicrobial susceptibility profiling of these strains was performed by using Kirby Bauer disk diffusion method. Phenotypic detection of the production of extended spectrum beta lactamase enzyme was performed using double disc synergy method and combination disc method.&#x0D; It has been identified that Klebsiella strains are highly resistant against Amoxicillin, Tetracycline, Nalidixic Acid, Cephradine, Gentamicin, co-amoxyclav with the percentage of 100%, 86%, 86%, 82%, 82% and 80% respectively. The most effective antibiotics for Klebsiella spp. were found to be Amikacin, Meropenem and Piperacillin-tazobactam, with highest sensitivities of 96%, 94% and 91%. Phenotypic detection of Extended spectrum beta lactamase production by double disc synergy test was able to identify 28% ESBL producers among Klebsiella isolates whereas 64% were detected by combination disc test.

The frequency of bla Verona imipenemase and bla imipenemase genes in clinical isolates of Pseudomonas aeruginosa in therapeutic centers of Zahedan

Introduction: Pseudomonads are very important as an opportunistic bacterium among gram-negative bacteria. Class B beta-lactamases such as Verona imipenemase (VIM) and Imipenemase (IMP) are the most important contributors to the resistance of gram-negative bacteria like Pseudomonas aeruginosa. These enzymes were isolated from burn wounds in Zahedan due to extended spectrum beta-lactamase (ESBL) activity and high resistance to β-lactamase antibodies (IMP and VIM) in P. aeruginosa isolates. Objectives: This study was aimed to determine the frequency of VIM, IMP beta-lactamase genes in clinical isolates of P. aeruginosa isolated from therapeutic centers of Zahedan. Materials and Methods: In this descriptive cross-sectional study, 125 samples of P. aeruginosa from burn wounds were collected from patients who were hospitalized in Zahedan as well as were cultured. Suspected colonies of P. aeruginosa were identified using common biochemical methods. The Kirby Bayer method was used to measure antibiotic susceptibility, and then the minimum inhibitory concentration (MIC) of these strains was examined. The genotypes of the β-lactamase genes of IMP and VIM were investigated in polymerase chain reaction (PCR) strains. Results: In this study, 125 isolates of P. aeruginosa were found in 32 isolates (26%) producing ESBL. In general, the resistance of P. aeruginosa to the antibiotics of imipenem, piperacillin, ceftazidime, cefotaxime, ceftriaxone, levofloxacin, ciprofloxacin, gentamicin, amikacin, streptomycin, tetracycline, and carbenicillin were 88%, 93%, 89%, 98%, 97%, 89%, 84%, 82%, 97%, 91%, 90% and 95%, respectively. According to the PCR test, 32 isolates with ESBL enzymes were 43.75 and 18.75, respectively. Conclusion: The prevalence of ESBLs and antibiotic resistance in the burn injuries of hospital is high and requires such as antibiotic susceptibility test, rational administration of antibiotics and the control of beneficial factors. The results showed that most of the samples were resistant to the drug and the frequency of blaVIM genes was higher than blaIMP among the strains producing ESBLs.

The occurrence of blaTEM, blaSHV and blaOXA genotypes in Extended-Spectrum β-Lactamase (ESBL)-producing Pseudomonas aeruginosa strains in Southwest of Iran

Pseudomonas aeruginosa is considered as a potential nosocomial pathogen, which shows a great tendency for infecting immune-compromised individuals, particularly burn patients. Producing extended spectrum beta-lactamases (ESBL) enzymes by these bacteria resulting inactivation of penicillins and cephalosporins which renders drug resistance. The aims of this study were to assess the antimicrobial susceptibility pattern and the prevalence of resistance determinants in ESBL producing P. aeruginosa in hospitalized patients. A total of 165 isolates of P. aeruginosa which included in this study isolated from teaching Shiraz hospitals, southwest of Iran. Antimicrobial susceptibility of isolates to antibiotics was determined using disk agar diffusion test. For detecting ESBL producing bacteria, all P. aeruginosa isolates that were resistant to Cefotaxime and/or Ceftazidime were examined for resistant to combined disks of Ceftazidime + Clavulanic acid and/or Cefotaxim + Clavulanic acid. The presence of antibiotic resistance determinants were investigated by PCR method. The results revealed that 99 (60%) of the isolates were multiple-drug resistant (MDR) and 21 (12.7%) of the isolates were ESBL positive. Among 21 ESBL-producing strains, 19 (90.5%), 11 (52.4%) and 7 (33.3%) strains were carrying blaOXA-10, blaSHV and blaTEM gene, respectively. The association between beta-lactamase genes with origin of isolates and drug resistance in this study indicates that further work with larger sample size is necessary to find out the actual involvement of P. aeruginosa strains carried these genes in the course of infections in burn patients.

Fingerprinting and genetic relationship among Escherichia coli strains producing B. Lactamase collected from urine using ERIC/PCR Assay

This study was conducted on 50 isolates recovered from urine samples of patients with urinary infections admitted to Azadi teaching Hospital/Dohuk City. These isolates were identified and characterized in previous study as E. coli producing extended spectrum beta lactamase enzymes, all isolates were subjected to Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC PCR) assay for estimation the fingerprinting and genetic relationship among these isolates. They were successfully producing multiple amplicons ranging from 2-12 bands with different molecular weights ranging from 5212- 213bp. The most frequent band was 724 which was amplified by 31 strains, and the least frequent were 3224, 2424, 1472 and 531bp. observed in only one strain. From the result of dendogram analysis revealed that all isolates were assigned into two main clusters, each cluster was further classified into two subgroups. Similar genotype may indicate clonal spreading of bacteria in hospital wards.

Antibiotic Resistant Gene Exchanged Between Escherichia coli and Staphylococcus aureus

Escherichia coli infections are becoming difficult treated because of extensive resistance to antibiotic among these organisms and manufacturing extended-spectrum beta lactamases enzymes (ESBLs) make them resistant to beta-lactam antibiotics. This study aims to offer a summary of the main horizontal transmission apparatuses between E. coli as well as Staphylococcus aureus and emergence resistance to antibiotics. Fifty of the E. coli and 50 of S. aureus isolates were examined to obtain minimum inhibitory concentration (MIC) results. These isolates were then tested by conventional polymerase chain-reaction for the existence or absence the sulfhydryl variable SHV beta-lactamase genes. About (48%) of isolated E. coli , while (32%) of S. aureus were revealed SHV gene.

Molecular Detection of TEM, SHV and CTX-M Genes Among Gram-negative Klebsiella Isolates.

In the past few years, the use of antimicrobial drugs against a wide range of pathogens has increased significantly. This extensive use of drugs has increased the resistance rate in microbial community widely. Molecular techniques for the detection of resistance are more reliable as compared to the conventional phenotypic method. The family Enterobacteriaceae is considered to be an important cause of nosocomial infections due to its predominantly active species such as E. coli, Klebsiella and Pseudomonas. These organisms are mainly involved in causing pneumonia, sepsis, post-surgical and urinary tract infections. Resistance against antimicrobial drugs among these isolates is increasing more rapidly all over the world. This study primarily focuses on the resistant isolates of Klebsiella species. The drug resistance in Klebsiella isolates is found to be associated with the production of resistance enzymes such as beta lactamase and extended spectrum beta lactamase (ESBLs) which confer resistance, most specifically against cephalosporins and extended spectrum cephalosporins. Since these enzymes are plasmid mediated, they can also produce resistance against several other antimicrobials. It has been found that among the genus Klebsiella, ESBLs are more prevalent in K. pneumoniae followed by K. oxytoca. In this study, we estimated the distribution of ESBL producers among Klebsiella species and performed their genetic characterization. A total of 236 gram-negative isolates were collected from different microbiological laboratories, during the period January 2010 till January 2012. Among these gram-negative isolates, 125 were identified as Klebsiella species. After species identification, Kirby Bauer disk diffusion method was used for antimicrobial susceptibility profiling. Furthermore, the phenotypic detection of ESBL producers was performed by double disc synergy and combination disc methods. Resistance genes responsible for the production of beta lactamase and extended spectrum beta lactamase enzymes were detected by Polymerase chain reaction. DNA sequencing was performed by selecting an ESBL producing Klebsiella pneumoniae strain with a positive blaTEM gene. In this study, we found 48%, 43.2% and 2.4% of SHV, TEM, and CTX-M resistance genes respectively in Klebsiella isolates. The DNA sequence ESBL and blaTEM positive Klebsiella strain showed 94% similarity with Klebsiella pneumoniae KUN5033 blaTEM gene for class A beta-lactamase TEM-198 analyzed by the Basic Local Alignment Search Tool (BLAST). Since there is an intense need of research in the field of drug resistance for implementing strict antibiotic control policies in hospitals, health care centers, laboratories, etc., the present study is dedicatedly conducted to estimate the drug resistant Klebsiella isolates, specifically the Beta lactamase and Extended Spectrum Beta Lactamase producers, at molecular level.

Prevalence of blaCTX-M, blaSHV and blaTEM β-Lactamase Genes Among Escherichia coli Isolates in Foodborne Outbreak in Iran

Aim: In this study we focused on evaluating the prevalence of ESBL enzymes genes that are including CTX-M, SHV, TEM β-lactamase among E. coli isolates in foodborne outbreak. Background: Extended Spectrum Beta-Lactamase (ESBL) has known as enzymes that are responsible for creating of high level of antimicrobial resistance in gram negative microorganism especially in E.coli. -Therefore, survey and identify of generating genes of these enzymes can be effective in controlling of resistance and helpful in using of appropriate βlactam drug against them. Material and Methods: Five hundredstool samples are including diarrhea with nausea, vomiting, abdominal cramps, fever and headache were selected by IMVIC biochemical test for E.coli . By making antimicrobial susceptibility test base on CLSI and using disk diffusion method and confirmatory test (combined disk) ,ESBLs samples were determined. Subsequently polymerase chain reaction (PCR) were performed for the following relative genes. Result: The highest - resistance in E. coli isolates was related to ampicillin (56%) -ESBLs positive were showed in (36%) samples , after PCR prosseccing the prevalence of SHV, TEM and CTX-M1 genes was (0%) , (18%) and (38%) respectively. Conclusions: Due to the prevalence of β-lactamase genes , accurate and rapid identification methods as PCR assay is essential. So, this can be considered as routine methods -