Phenotypic and Genotypic Detection of Metallo-Beta-Lactamases in Carbapenem Resistant Acinetobacter baumannii

Background: Carbapenem resistance in Acinetobacter baumannii has become a major concern for treating physicians. The aim of this study was to investigate the prevalence of metallo β-lactamase (MBL) genes (bla VIM , and blaIMP) among isolated multidrug-resistant A. baumannii . Methods: Fifty non-repetitive carbapenem-resistant A. baumannii isolates were collected. Antibiotic susceptibility was performed by disk diffusion method. MICs were determined by E test method. The resistant strains were tested for the production of carbapenemases by the Modified Hodge Test (MHT) followed by EDTA-disk synergy test was performed for metallo-β-lactamases (MBL) phenotypic detection. Detection of bla VIM , and blaIMP was performed by PCR followed by sequencing. Results: All isolates had a multidrug resistant profile, and were all resistant to all antibiotics including the carbapenems but remained susceptible to colistin. Among these isolates, Carbapenemase production was confirmed by the Modified Hodge test for 42 (84) isolates. Phenotypic method showed the production of MBL in 15 (30) isolates. PCR techniques revealed that out of 50 isolates, 13 (26) were positive for blaVIM and all were negative for blaIMP. Conclusion: Our study concludes that the high prevalence of carbapenem resistant Acinetobacter species with MBL production is one of the main concerns in our country and this situation needs strict infection control measures

Imipenem-resistant Pseudomonas aeruginosa strains carry vim-type metallo-beta-lactamases isolated from intensive care unit, Shahid Beheshti Hospital, North of Iran

Background: Pseudomonas aeruginosa is the causing agent of many hospital infections and metallo-beta-lactamases (MBL) are being reported with increasing frequency. The aim of this study was to determine the frequency of metallo-&beta-lactamases (MBL) and VIM-1 gene in multidrug-resistant strains of P. aeruginosa isolates and to compare the methods of phenotypic and molecular detection. Materials and Methods: In 2011- 2012, 50 samples of non – duplicate P. aeruginosa were isolated from intensive care units and tested for MBL production using phenotypic methods. Minimal Inhibitory concentrations (MICs) were determined by commercial micro dilution panels. The presence of metallo-&beta-lactamase (MBL) genes was established by polymerase chain reaction (PCR) with specific primers targeting the bla (VIM) genes. Results: We used 50 clinical isolates amongst which 18 (%36) were found resistant to imipenem. Productions of MBL were detected in 15 (30%) isolates applying phenotypic method. PCR assay showed that 9 (18%) isolates carried aVIM-1 gene. MBL- producing strains were shown 100% resistant to cefepime, ceftazidime, ceftriaxone, cefotaxime and imipenem. Amikacin and ofloxacin appeared to be the most active antimicrobial agent. Conclusion: These findings demonstrate the emergence of bla (VIM-1) producing P. aeruginosa in North of Iran. VIM metallo-beta-lactamases producing P. aeruginosa strains can cause serious infections that are difficult to treat, therefore, there is a need for rapid identification and the timely implementation of infection control measures in combination with systematic surveillance to monitor its potential clonal spread

Evaluation of Different Primers for Detection of Brucella by Using PCR Method

Introduction: Brucellosis is a worldwide zoonosis and a significant cause of loss of health in humans and animals. Traditionally, classic diagnosis is carried out by isolation of Brucella, which is time-consuming, technically challenging and potentially dangerous. The aim of this study was to expand a molecular test that would be used for the develop detection of Brucella in a single reaction with high sensitivity and specificity, by targeting IS711element. Methods: This study was carried out from 2015 to 2016 at the Ayatolla Rohani hospital in Babol, Iran. The present study was designed to develop PCR assay, based on IS711 gene for rapid diagnosis of Brucella spp. and immediate detection of Brucella, with high sensitivity and specificity. Four pairs of oligo-nucleotide primers with sizes of 547, 403, 291 and 127bp respectively, were planned to exclusively amplify the targeted genes of Brucella species. Results: Our results show that, five PCR primers set up, would be helpful in amplifying the DNAs from the genus Brucella with high specificity and sensitivity so it can be 12 fg, for Brucella species to provide a valuable tool for diagnosis. Conclusion: This method can be more useful than serological and biochemical tests and in addition, this reduces the number of required tests more rapidly and economically