Phenotypic and Antimicrobial Resistance Landscape of Klebsiella pneumoniae: Hypermucoviscosity, Biofilm Formation and Drug-Resistant Phenotypes

Quality Improvement Project (QIP)

Abstract

Background: Klebsiella pneumoniae (K. pneumoniae) is an important healthcare-associated pathogen in which antimicrobial resistance (AMR) may coexist with phenotypes that enhance persistence and complicate clinical management. This study characterized the AMR, hypermucoviscous, and biofilm-forming profiles of K. pneumoniae isolates from tertiary-care hospitals in Peshawar, Pakistan.

Methods: A total of 152 K. pneumoniae isolates collected from urine, pus, blood, sputum, wound swabs, and body fluids were phenotypically characterized. We assessed isolates for antimicrobial susceptibility against selected antibiotics and categorized them according to multi-drug-resistant/extensively drug-resistant (MDR/XDR) phenotypes. We evaluated hypermucoviscosity using the string test and determined biofilm-forming capacity using a standardized phenotypic assay.

Results: Of the 152 isolates, 81 (53.3%) were obtained from males and 71 (46.7%) from females. Urine was the predominant specimen source (52, 34.2%), followed by pus (33, 21.7%) and blood (26, 17.1%). Resistance was particularly high to cefazolin (90.1%), amoxicillin–clavulanate (87.5%), cefoxitin (84.2%), ceftriaxone (80.9%), and ceftazidime (79.6%). Carbapenem resistance was 20.4% for ertapenem and 19.1% for meropenem, whereas colistin resistance was 11.8%. Overall, 57 (37.5%) isolates were MDR and 36 (23.7%) were XDR. Hypermucoviscosity was identified in 114 (75.0%) isolates. Biofilm formation was heterogeneous, with 32 (21.1%) strong, 47 (30.9%) moderate, 35 (23.0%) weak, and 38 (25.0%) non-biofilm-forming isolates.

Conclusions: The frequent occurrence of antimicrobial resistance, MDR/XDR phenotypes, hypermucoviscosity, and biofilm formation demonstrates a substantial phenotypic burden of K. pneumoniae. Integrated antimicrobial stewardship, phenotypic surveillance, and strengthened infection-prevention strategies are warranted to mitigate its clinical impact.