Phenotypic Detection of Carbapenemase Producing Drug Resistant Gram Negative Bacteria in Rajshahi Medical College Hospital, Bangladesh

Background: Carbapenem resistance is a major and on-going public health problem globally and locally. It occurs mainly among Gram negative pathogens. Most of the Carbapenemase producing bacteria are multidrug resistant bacteria including 3rd generation of cephalosporin and carbapenems. Objective: To isolate and identify Carbapenemase producing drug resistance gram negative bacteria with their antibiogram in Rajshahi Medical College Hospital (RMCH). Methods: A Cross-sectional descriptive study was carried out in different surgical units of RMCH. A total of 250 wound swabs collected from the respective patients as sample referred to Microbiology department of Rajshahi Medical College for investigation. The specimens were inoculated in blood agar, nutrient agar and MacConkey’s agar media and incubated aerobically at 370 C for 24 hours. The isolated bacteria were identified by their colony morphology, pigment production, haemolysis on blood agar plate, motility test, Gram staining and relevant biochemical tests. Susceptibility tests of the bacterial isolates were done by using the modified Kirby Bauer disk diffusion method on Mueller Hinton agar media. Carbapenemase producing bacteria were identified phenotypical- ly by modified Hodge test. Results: Out of a total 250 samples, culture yielded growth were 213(85.2%) and 37(14.8%) had yielded no growth. Female were predominant 146(58.4%) in comparison to male 104(41.6%) with a male female ratio 1: 1.4. Maximum 47.2% cases were within the age group of 19-30 years. Among the culture positive isolates, Gram negative organisms were higher (58.8%) than gram positive (41.2%). S. aureus was the predominant organism 71(30.8%) followed by P. aeruginosa 67(29%), E. coli 43(18.7%) and Klebsiella spp. 20(8.7%). Among 67 isolated P. aeruginosa and 82 isolated Enterobacteriaceae, 18(26.8%) and 14(17%) were carbapenemase producers respectively. Conclusion: It may be concluded that, most of the isolated Carbapene- mase producing gram negative bacteria are multidrug resistant and causes complicated infections. So, it is necessary to perform sensitivity test prior to start antimicrobial therapy for proper management and routine screening test for carbapenemase producing should be practiced to detect the carriers and treat them adequately and also reduce and control the spread of antimicrobial resistance.