Antimicrobial susceptibility patterns of bacterial isolates from routine clinical specimens of a tertiary hospital in Bangladesh

Background and objectives: To prevent the emergence and spreading of antimicrobial resistance, especially multidrug resistance in pathogenic bacteria, the selection of appropriate antibiotics is a prerequisite for the effective treatment of infection.This study aimed to analyze the prevalence and antimicrobial resistance patterns of bacterial isolates from various clinical samples in a tertiary care hospital. Methods: This study was conducted at a teaching hospital of Dhaka city, Bangladesh from January 2020 to March 2021. The results of culture and antimicrobial susceptibility of bacterial isolates from various clinical samples were collected and analysed. Identification of bacteria and antimicrobial susceptibility test were performed according to the standard methods. Results: A total of 1277 bacterial isolates was analyzed. Of them, 1072 (83.95%) were Gram-negative, and 205 (16.05%) were Gram-positive bacteria. Among the isolates, Escherichia coli (n=576), Enterobacter spp. (n=150), Klebsiella spp. (n=140), and Staphylococcus aureus (n=117) were predominant.The Enterobacteriaceae showed higher resistance to cephradine (94.3%) and cefuroxime (76.7%), whereas least resistant to imipenem (10.1%) and meropenem (14.8%). Pseudomonas spp. was highly resistant to ceftriaxone (80.2%), and colistin (70.8%), whereas least resistant to piperacillin-tazobactam (15.1%). Colistin was the most effective agent (resistance 6.7%) against Acinetobacter spp. Linezolid (resistance 1%) and vancomycin (resistance 2%) were highly effective against Gram-positive bacteria. Among the Staphylococcus aureus, 95.7% were methicillin-resistant (MRSA). A total of 889 (69.6%) bacterial isolates were identified as multidrug resistant. Multidrug resistance was more prevalent in Gram-positive isolates (79.5%) than that of Gram-negative bacteria (67.7%). Furthermore, 7.5% of Gram-negative bacterial isolates were resistant to all seven classes of antibiotics tested. Conclusions: This study revealed presence of high rate of resistance to several antimicrobial agents in bacteria isolated from various clinical samples.The findings would help healthcare professionals to select appropriate antibiotics for the effective treatment of infections and to develop antibiotic stewardship protocol. IMC J Med Sci 2022; 16(1): 005 *Correspondence: M. Mahboob Hossain, Microbiology Program, Department of Mathematics and Natural Sciences (MNS), BRAC University, 66 Mohakhali, Dhaka 1212. E-mail: mmhossain@bracu.ac.bd