Phenotypic detection of β-lactamases producing Klebsiella pneumoniae and Acinetobacter baumannii isolated from the respiratory tract infections.

Authors: Shilpa Borehalli Mayegowda, Priyanka Lakshman, Sushma S Murthy, Manjula Nagalapur Gadilingappa

DOI: 10.18231/j.ijmmtd.11625.1758782202

Keywords: Antimicrobials, ESBL, MBL, Antibiotic susceptibility test, Colistin.

Abstract: The limited treatment options have elevated an increased cause of concerns toward the emerging antimicrobial resistance amongst the bacterial pathogens in hospital settings, causing respiratory tract infections (RTI). To address the alarming condition, following study aimed to determine the antibiotic susceptibility (AST) patterns, and extended spectrum β-lactamases (ESBL) and Metallo β-lactamase (MBL) production in Klebsiella pneumoniae and Acinetobacter baumannii isolated from RTI samples collected during June 2020 to September 2022. In the current study, 1624 samples (sputum, tracheal secretions, suction tip) collected from respiratory tract specimens were analyzed and phenotypically characterized. Of 12.3 % (200 isolates), the recorded prevalence rate of K. pneumoniae was 10.3% while that for A. baumannii was 1.9 %. Following AST, K. pneumoniae displayed highest resistance against Ampicillin (95 %), followed by Amoxycillin/clavulanic acid (91 %), and the lowest recorded susceptibility was for Tigecycline (39.2 %). While, A. baumannii expressed susceptibility to Carbapenem group and Ciprofloxacin (84.3 %), lowest was for displayed against Tigecycline (50 %). The overall study exhibited Colistin retaining its activity with 100 % sensitivity. ESBL production in K. pneumoniae was 31 % and 0% in A. baumannii. While, prevalence rate observed for MBL producers was 11 %, K. pneumoniae and A. baumannii recorded at 9.5 % and 25 % respectively. The increasing rates of ESBL producers is concerning and more studies are required to battle these infections due to their increasing resistance to carbapenem. The current study highlights the use of Colistin as the best available antimicrobial for treating such RTI pathogens. Therefore, continuous monitoring of antibiotic-resistant profiles will help to guide effective antimicrobial therapy and management.