Biofilm Formation and Associated Gene Expression in Multidrug-Resistant Klebsiella pneumoniae Isolated from Clinical Specimens.

Biofilms reduce the bacterial growth rate, inhibit antibiotic penetration, lead to the development of persister cells and facilitate genetic exchange. The biofilm-associated Klebsiella pneumoniae infections have not been well studied, and their implications in overcoming the effects of antimicrobial therapy are yet to be fully understood. Hence this study evaluated the antibiotic resistance pattern, antibiotic resistance determinants of extended-spectrum beta-lactamase (ESBL) family. Biofilm-forming ability of seventy multidrug-resistant clinical isolates of K. pneumoniae and the biofilm-associated genes of representative biofilm formers from a tertiary care hospital were also assessed. The K. pneumoniae isolated from urine exhibited resistance towards ceftazidime, nalidixic acid and meropenem. Isolates from blood were resistant to cefuroxime. Higher rates of resistance were observed towards cefuroxime, nalidixic acid, and meropenem for the isolates from the endotracheal aspirate. Extended spectrum beta-lactamase production by CLSI's disc diffusion-based confirmation test revealed all the K. pneumoniae to be as ESBL producers. Most of the isolates harboured the bla gene variants, blaSHV and blaTEM. Majority of the isolates were colistin sensitive. 97.1% of the K. pneumoniae produced biofilm. K. pneumoniae isolated from pus and blood produced fully established biofilms. Strong biofilm formers were sensitive to co-trimoxazole and ciprofloxacin. Moderate biofilm formers exhibited sensitivity towards meropenem and imipenem. Expression of the fimH gene was increased, while mrkD showed reduced expression among the strong biofilm formers. Moderate biofilm formers showed variable expression of the genes associated with the biofilm formation. The weak and non-biofilm formers showed reduced expression of both the fimbrial genes. Multidrug-resistant isolates produced ESBLs and formed well-established biofilms.

Whole-genome-based analysis reveals multiclone Serratia marcescens outbreaks in a non-Neonatal Intensive Care Unit setting in a tertiary care hospital in India.

We report the use of next generation sequencing (NGS) for investigating an outbreak of 13 cases of Serratia marcescens blood stream infections in a non-Neonatal Intensive Care Unit (non-NICU) setting in a tertiary care hospital in India over 5 months. Thirteen cases of sepsis due to S. marcescens were identified in various Intensive Care Units (ICUs) over 5 months. Environmental surveillance identified isolates in the adult ICU (AICU). Antibiogram did not correlate with timeline. Sequencing libraries were prepared using Nextera XT chemistry (Illumina). Based on NGS, two clusters were identified. Cluster 1 had environmental and clinical isolates from the AICU and cluster 2 were isolates from the Coronary Care Unit (CCU). NICU and Paediatric ICU isolates did not belong to any cluster. Polyclonal outbreaks best identified by NGS can occur simultaneously. Good infection prevention practices like hand hygiene for compounded medicines and surface cleaning helped end the outbreak.