Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determin...Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.展开更多
giving results of antimicrobial susceptibility testing(AST)even if the infection is detected due to a single type of bacteria.However,what should be the minimum number of colonies?The clinical laboratory manuals are s...giving results of antimicrobial susceptibility testing(AST)even if the infection is detected due to a single type of bacteria.However,what should be the minimum number of colonies?The clinical laboratory manuals are silent and give different numbers.Thus,the present study was conducted to evaluate the impact of picking up more than one colony for antimicrobial susceptibility.Method:The study was conducted on those clinical samples yielding Escherichia coli either as pure culture or as a prominent cause of infection.The impact of testing multiple colonies of Escherichia coli isolates was assessed on AST results through the detection of extended-spectrum β-lactamase(ESBL)producing and Metallo-β-lactamase(MBL)producing Escherichia coli carriage in clinical samples.Results:A total of 1031 samples having E.coli as the most prominent or single pathogen were analyzed.It included testing either one,two,three,four,five,or more than five(6-10)representative E.coli colonies from 526,247,115,76,31,and 36 samples,respectively.The study revealed that testing of less than three representative colonies significantly(p<0.05)impacts the outcome.However,the best outcome was when≥6 representative colonies were tested for AST.Conclusion:The study suggested that≥6 representative colonies should be emulsified for antimicrobial susceptibility tests not to miss possible infection with ESBL or MBL-producing mutants,even in mono-culture infections.展开更多
文摘Objective: Increasing the emergence of Metallo-β-lactamase (MBL) producing gram-negative bacteria and their dexterous horizontal transmission demands rapid and accurate detection. This study was conducted to determine a suitable method to promptly detect MBL-producing gram-negative bacteria. Methods: A total of 103 gram-negative bacteria were identified from various clinical samples at a tertiary care hospital in Dhaka city. MBL producers were detected by two phenotypic methods, the Disk Potentiation Test (DPT) and the Double Disk Synergy Test (DDST) based on β-lactam chelator combinations where EDTA/SMA has been used as an inhibitor and Imipenem, Ceftazidime as substrates. Results: 103 isolates which were identified as Escherichia coli spp, Klebsiella spp, Pseudomonas spp, Acinetobacter spp, Proteus spp, Providencia spp were found to be multidrug-resistant in antibiogram test. Isolates showed complete resistance (100%) to Imipenem, Meropenem, and Amoxiclav. The highest carbapenem-resistant etiological agents were Acinetobacter spp 40 (38.8%) followed by Pseudomonas spp 27 (26.2%), Klebsiella spp 26 (25.2%), Escherichia coli 8 (7.8%), Proteus spp 1 (1%) and Providencia spp 1 (1%). DPT method detected significantly (p = 0.000009) a higher number of MBL-producers (Imipenem with 0.5 M EDTA n = 61, 59.2% & Ceftazidime with 0.5 M EDTA n = 56, 54.4%) compared to the DDST method (Imipenem -0.5 M EDTA n = 43, 41.7%, Imipenem – SMA n = 38, 36.9% & Ceftazidime -0.5 M EDTA n = 15, 14.6%). Conclusion: Pieces of evidence suggest that DPT is a more sensitive method than DDST and could be recommended for identifying MBL-producing bacteria in Bangladeshi hospitals for the proper management of patients, to reduce time constraints and treatment costs.
基金supported by ICAR-Indian Veterinary Research Institute,Izatnagar-243122,India,under an ongoing service project(IVRI-Epid/2014-25).
文摘giving results of antimicrobial susceptibility testing(AST)even if the infection is detected due to a single type of bacteria.However,what should be the minimum number of colonies?The clinical laboratory manuals are silent and give different numbers.Thus,the present study was conducted to evaluate the impact of picking up more than one colony for antimicrobial susceptibility.Method:The study was conducted on those clinical samples yielding Escherichia coli either as pure culture or as a prominent cause of infection.The impact of testing multiple colonies of Escherichia coli isolates was assessed on AST results through the detection of extended-spectrum β-lactamase(ESBL)producing and Metallo-β-lactamase(MBL)producing Escherichia coli carriage in clinical samples.Results:A total of 1031 samples having E.coli as the most prominent or single pathogen were analyzed.It included testing either one,two,three,four,five,or more than five(6-10)representative E.coli colonies from 526,247,115,76,31,and 36 samples,respectively.The study revealed that testing of less than three representative colonies significantly(p<0.05)impacts the outcome.However,the best outcome was when≥6 representative colonies were tested for AST.Conclusion:The study suggested that≥6 representative colonies should be emulsified for antimicrobial susceptibility tests not to miss possible infection with ESBL or MBL-producing mutants,even in mono-culture infections.
