Abstract:

Background and Aims: Gram-negative bacteria are important pathogens that can cause community- and hospital-acquired infections as well as opportunistic infections, with antimicrobial resistance in Gram-negative bacteria becoming a growing crisis in clinical medicine. Biofilm formation is one of the mechanisms of bacterial resistance, which makes bacteria less susceptible to antimicrobial agents and unable to be killed by host immune mechanisms. Therefore, this study investigates the antimicrobial resistances and biofilm-forming abilities of a total of 98 Gram-negative strains isolated from various clinical specimens. Methods: A disc diffusion assay was performed to detect the susceptibility profiles of 98 Gram-negative strains. The biofilm- forming abilities of strains were also determined using the Crystal Violet assay. Results: Concerning the disc diffusion assay, most of the isolates were found to be resistant to carbapenems, with more than 90% of Acinetobacter baumannii, Klebsiella pneumoniae and Escherichia coli isolates being found resistant to ceftazidime and piperacillin. Most of the Pseudomonas aeruginosa isolates (75%) were found to be resistant to imipenem and aztreonam. All isolates had the ability to form biofilms. Overall, 56% of isolates were strong formers, and 29% were moderate biofilm formers. Strong biofilm formation was observed in most strains except for K. pneumoniae. Conclusion: The surveillance of susceptibility profiles and biofilm formation is important for determining their variable sus- ceptibility patterns and aiding in the appropriate management of infections caused by these organisms.

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