Biofilm-producing and specific antibiotic resistance genes in Pseudomonas aeruginosa isolated from patients admitted to a tertiary care hospital, Bangladesh.

Objectives: Biofilms are responsible for persistent infections and antimicrobial resistance. Pseudomonas aeruginosa was investigated with its ability to form biofilm by detecting genes responsible for producing biofilms and biofilm-specific antimicrobial resistance. The association between antibiotic resistance and biofilm was investigated. Methods: This cross-sectional study was conducted from July 2017 to December 2018. A total of 446 samples (infected burn, surgical wounds, and endotracheal aspirate) were collected from admitted patients of Dhaka Medical College and Hospital, Bangladesh. P. aeruginosa was isolated and identified by biochemical tests and polymerase chain reaction. Biofilm production by tissue culture plate method followed by detection of biofilm-producing genes (pqsA, pslA, pslD, pslH, pelA, lasR) and biofilm-specific antibiotic resistance genes (ndvB, PA1874, PA1876, PA1877) by polymerase chain reaction were done. Antibiotic susceptibility test was carried out by disk diffusion method; for colistin agar dilution method of minimal inhibitory concentration was followed. Results: Among 232 (52.02%) positive strains of P. aeruginosa, 24 (10.30%) produced biofilms in tissue culture plate. Among biofilm-producing genes, pqsA was the highest (79.17%). pslA and pelA were 70.83%, pslD 45.83%, pslH and lasR 37.5%. Among biofilm-specific antibiotic resistance genes, 16.67% were ndvB, and 8.33% were PA1874 and PA1877. Biofilm-forming strains were significantly resistant to colistin. Conclusions: Detection of biofilm-forming genes may be a good tool for the evaluation of biofilm production, which will help in prompt and better management of chronic or device-associated infections.

Antimicrobial Susceptibility Pattern of Extended-spectrum Beta-lactamases Producing Organisms Isolated in a Tertiary Care Hospital, Bangladesh.

CONTEXT: Infection caused by extended-spectrum beta-lactamases (ESBL) producing organism is a major problem regarding antibiotic resistance. AIMS: The aim of this study was to find out the antibiogram of ESBL producing organisms isolated from various samples. SETTINGS AND DESIGN: This cross-sectional study was carried out in the Department of Microbiology of a Tertiary Care Hospital, Dhaka, Bangladesh from January to June 2014. SUBJECTS AND METHODS: One Hundred and seventy-nine ESBL producing Gram-negative organisms detected phenotypically by double-disc synergy test were enrolled in this study. Required data were collected from the records of the Microbiology laboratory. RESULTS: ESBL production was detected in 16.07% (179/1114) of isolated organism. Of Escherichia coli, 15.75% were ESBL producers; 14.01% Pseudomonas spp., 36.84% Proteus spp., 18.57% Klebsiella spp., and 21.05% of Acinetobacter spp., were ESBL producers. Maximum (43.58%) ESBL producers were isolated from surgery departments, and wound swabs yielded majority (53%) of them. About 13% ESBL producers were isolated in outdoor patients mostly from community-acquired infections. Most ESBL producers were resistant to commonly used antibiotics. Carbapenems especially imipenem was the most effective drug showing excellent sensitivity; colistin and piperacillin/tazobactam also had better sensitivity result. Most of the ESBL producers showed a good sensitivity to amikacin, but all of them were highly resistant to ciprofloxacin. CONCLUSIONS: ESBL production should be detected routinely in all Microbiology laboratories. Infection control, rational use of antibiotics must be done promptly to prevent the development and spread of ESBL producing organisms.