Comparision of Three Laboratory Tests for Detection of AmpC β Lactamases in Klebsiella Species and E. Coli (original) (raw)
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Journal of the Medical Sciences (Berkala Ilmu Kedokteran)
Escherichia coli and Klebsiella sp. are the predominant species isolated from clinical samples. Recent and proper understanding of the antibiotic susceptibility pattern of extended-spectrum β-lactamases (ESBL) and AmpC β-lactamases (AmpC) producing E. coli and Klebsiella sp. will prevent the distribution and future incidence of ESBL and AmpC. We designed this study to understand antibiotic susceptibility patterns of ESBL and AmpC producing E. coli and Klebsiella sp. isolated from a tertiary care hospital in North India. A cross-sectional study was conducted from March 2021 to February 2022. Guring this period, various clinical samples were collected and further tested for ESBL producing E. coli and Klebsiella sp. by using the Double disc Synergy test, whereas AmpC was detected by the Boronic acid disk potentiation method. Their antibiotic susceptibility patterns were noted. Various clinical specimens were collected, in which 37.95% were shown growth of bacteria. Among them, 46.67% o...
Journal of evolution of medical and dental sciences, 2016
Resistance to broad spectrum β-lactams mediated by Extended Spectrum β-lactamases (ESBL) and AmpC β-lactamases enzymes is a growing threat worldwide. AIM The aim of the study was to detect the prevalence and antimicrobial susceptibility of ESBL and AmpC β-lactamase producing Escherichia coli and Klebsiella pneumoniae isolated from various clinical samples. MATERIALS AND METHODS A total of 288 isolates comprising of 180 Escherichia coli and 108 Klebsiella pneumoniae isolated from various clinical samples were included. ESBL was detected by Phenotypic Confirmatory Disc Diffusion Test (PCDDT) and Double Disk Synergy Test (DDST). AmpC detection was done by AmpC disk test. RESULTS Out of 180 Escherichia coli and 108 Klebsiella pneumoniae isolates 91 (50.5%) and 63 (58.3%) were confirmed to be ESBL producers by PCDDT and 81 (45%) and 57 (52.7%) by DDST respectively. AmpC was detected in 35 (19.4%) of Escherichia coli and 33 (30.5%) of Klebsiella pneumoniae isolates. Co-production of ESBL and AmpC was detected in 6 (3.3%) Escherichia coli and 11 (10.2%) of Klebsiella pneumoniae isolates. Majority of ESBL producers were from blood in both organisms. Multidrug resistance (MDR) was seen in 79.1% of ESBL Escherichia coli and 63.5% of ESBL Klebsiella pneumoniae isolates. MDR was seen in 28 (96.5%) of AmpC producing Escherichia coli and all AmpC producing Klebsiella pneumoniae isolates. CONCLUSION It is essential to report ESBL and AmpC beta lactamase production along with routine susceptibility, which will aid the clinicians in prescribing antibiotics. Strict adherence to the hospital antibiotic policy and good infection control practices would go a long way in curtailing the menace of drug resistance.
European Chemical Bulletin, 2018
Multiplex PCR for the detection of AmpC genes has proved useful as a rapid screening tool to distinguish cefoxitin resistant non-AmpC producers from cefoxitin resistant AmpC producers. In addition to AmpC gene detection, the data generated from the multiplex PCR method can distinguish which family of AmpC gene is present in the resistant organism thereby distinguishing possible inducible AmpC producers from non-inducible producers of AmpC. The present study was designed to evaluate these issues among cephalosporin-resistant isolates of Klebsiella spp. and to assess the performance characteristics of phenotypic tests, using different inhibitors, compared to the PCR, for their rapid and accurate detection. Fifty eight out of 100 isolates were AmpC producers by PCR. Fifty six out of 58 isolates that were positive by PCR test were resistant to FOX. Thirty out of 58 AmpC producers were ESBL positive by E-test and MDDST in detection of ESBL in the presence of AmpC. While 23 /58 were positive by DDST for detection of ESBL in presence of Amp. This study reveals high prevalence of pAmpC and ESBL enzymes among bacterial isolates from our hospital. ESBL production may mask the phenotypic detection of pAmpC enzymes. Modified 3 dimensional(M3D) is a simple and reliable method for detection of pAmpCs. MDDST serve as reliable confirmatory tests for detection of ESBLs in AmpC-positive isolates.
Clinical Microbiology and Infection, 2010
There are currently no standardized diagnostic tests available for the reliable detection of AmpC b-lactamases in Klebsiella spp., Escherichia coli, Proteus mirabilis and Salmonella spp. A study was designed to evaluate a confirmation disk test using cefotetan (CTT) and cefoxitin (FOX) with phenylboronic acid (PBA). It also investigated the most suitable screening concentrations of FOX, ceftriaxone (CRO) and ceftazidime (CAZ) for the detection of AmpC b-lactamases. A total of 126 control (consisting of 11 laboratory and 115 wellcharacterized clinical strains) and 29 840 non-repeat clinical isolates were included. FOX with PBA used in a confirmation test and CRO and CAZ as screening agents were found to be unreliable. FOX at ‡ 32 mg/L was the best screening agent and CTT with PBA was the best confirmation test. Of the clinical isolates 635 (2%) were found to be resistant to cefoxitin (MIC ‡ 32 ug/mL) and 332 (52%) were AmpC positive. E. coli was the most common organism with AmpC b-lactamases and was mostly present in urines from community patients. It is recommended that laboratories use FOX at 32 mg/L as a screening agent and perform a disk test with CTT and PBA to confirm the presence of an AmpC cephalosporinase in isolates of Klebsiella spp., E. coli, Salmonella spp. and P. mirabilis. This approach is convenient, practical and easy to incorporate into the workflow of a clinical laboratory. False-positive AmpC detection may occur with KPC-producing bacteria when inhibitor-based methods are used.
Indian Journal of Medical Microbiology, 2005
The purpose of this study was to simultaneously screen for Extended-spectrum β-lactamases (ESBL) and AmpC βlactamases in gram negative clinical isolates from four tertiary care hospitals and further to compare two detection methods three-dimensional extraction method and AmpC disk test for AmpC β-lactamases. A total of 272 isolates were screened for ESBL and AmpC ß-lactamase by modified double disk approximation method (MDDM). Synergy observed between disks of ceftazidime/cefotaxime and clavulanate were considered as ESBL producer. Isolates showing reduced susceptibility to either of the test drugs (ceftazidime or cefotaxime) and cefoxitin were considered as presumptive AmpC producers and further confirmed by three-dimensional extraction method and AmpC disk test. A total of 173 (64%) of the isolates were found to be ESBL positive and 61 (23%) showed resistant to cefoxitin. ESBL was detected in 80 (62%) isolates of E. coli and 71 (73%) of Klebsiella spp. The occurrence of AmpC β-lactamases was found to be 8% (22) of the total isolates and the two detection methods for AmpC β -lactamase showed concordant results. Screening for ESBL and AmpC can be simultaneously done by MDDM method and confirmation for AmpC ß-lactamase should be carried out routinely in tertiary care hospitals by AmpC disk test, as it is a simple and rapid procedure.
The Indian journal of medical research, 2012
AmpC β-lactamases which are often plasmid mediated hydrolyze all β-lactam antibiotics except cefepime and carbapenems. We evaluated the presence of AmpC β-lactamases among Enterobacteriaceae strains recovered prospectively from patients at five Indian tertiary care centres. The study included 909 consecutive Gram-negative isolates recovered from clinically significant specimens during June 2007 - May 2008 as part of an ICMR-ESBL study. Among the study isolates, 312 were found to be cefoxitin resistant by disc diffusion test (DDT). Minimum inhibitory concentration (MIC) determination by E test was done against amikacin, levofloxacin, impinem, meropenem, ertapenem, tigecycline and piperacillin-tazobactam. Combined DDT using phenyl boronic acid as inhibitor with cefoxitin was used for phenotypic confirmation of AmpC phenotype. The common Amp C genotypes ACC, FOX, MOX, DHA, CIT and EBC were detected by multiplex PCR. Plasmid mediated Amp C phenotype was confirmed in 114 of the 312 (36.5...
Diagnostic Microbiology and Infectious Disease, 2000
Escherichia coli and Klebsiella spp. were screened for ESBL based on routine susceptibility testing results. Isolates with intermediate or resistant susceptibilities for extended spectrum cephalosporins or aztreonam were reported as probable ESBL producers. By using the NCCLS proposed ESBL confirmatory method, we tested 61 screen-positive isolates from 42 patients, 30 randomly selected susceptible isolates, and 12 isolates with previously characterized -lactamases. Ceftazidime contributed to 97% of screen-positive isolates, whereas aztreonam added a single patient isolate. An ESBL was confirmed in 86% of K. pneumoniae, 100% of K. oxytoca, and 20% of E. coli screen-positive single patient isolates. None of the susceptible isolates were shown to produce ESBL. Based on these findings a comment regarding the presence of ESBL seems sufficient for Klebsiella spp. but confirmatory testing is indicated for E. coli. There was 85% agreement between the type of -lactamase and the result of the ESBL confirmatory test. When a cefotaxime MIC Ͼ 0.25 g/mL was used to indicate the presence of ESBL, the specificity of the assay increased to 100%. The NCCLS ESBL phenotypic confirmatory method was reproducible and accurate enough to be used in the clinical laboratory.
Journal of Clinical Microbiology, 2004
A new cefoxitin-agar medium (CAM)-based assay was compared to the previously published modified three-dimensional (M3D) assay for the detection of AmpC production in Escherichia coli and Klebsiella pneumoniae. Clinical isolates of cefoxitin-resistant E. coli (n ؍ 5) and K. pneumoniae (n ؍ 7) and multiple control strains with and without AmpC enzymes were tested by both methods. The CAM method with 4 g of cefoxitin/ml was equivalent to the M3D method for detecting AmpC production in E. coli and K. pneumoniae. This new method is easier to perform and interpret and allows for testing of multiple isolates on a single plate.