Molecular surveillance and dissemination of Klebsiella pneumoniae on frequently encountered surfaces in South African public hospitals.

Abstract

Hospital equipment and surfaces can harbour Klebsiella pneumoniae. In the absence of effective cleaning, anyone who encounters these surfaces can unknowingly spread this opportunistic pathogen throughout the hospital. This study aimed to investigate the prevalence of K. pneumoniae on inanimate surfaces and evaluate the genetic diversity, antibiotic resistance and virulence profile of the recovered isolates. Overall, 777 swab samples were collected from four different South African public hospitals classified as central (A), tertiary (B), regional (C) and district (D). These samples were taken from 11 predetermined surfaces present in three different wards: the intensive care unit (ICU), paediatric and general. K. pneumoniae was identified using polymerase chain reaction (PCR) followed by antibiotic susceptibility testing using disk diffusion. Extended-spectrum β-lactamases (ESBL) producers were characterised using the combination disc method. Six resistance and three virulence genes were screened using PCR. The genetic diversity of the isolates was examined using enterobacterial repetitive intergenic consensus (ERIC)-PCR. Collectively, 75 (10%) K. pneumoniae isolates were recovered from the collected samples. The isolates recovered were equally abundant in tertiary hospital B and district hospital D. The recovery of K. pneumoniae was highest in the paediatric ward. Six sites harboured K. pneumoniae wherein the occupied beds were the most heavily contaminated. Thirty (40%) isolates were identified as ESBL producers and detected in high quantities in tertiary hospital B and the ICU. The ESBLs were mostly classified as multidrug-resistant (MDR), displaying higher resistance levels to the antibiotics screened than non-ESBLs. Majority of the ESBLs harboured the blaCTX-M group one resistance gene, which was significantly (p<0.05) associated with the aminoglycoside [aac(3')-II and aac(6')-Ib] and fluoroquinolone genes (qnrB) screened. The prevalence of virulence genes was high, mrkD (95%), wabG (93%) and entB (92%). ERIC-PCR demonstrated that clonally related isolates were recovered from different sites within the same hospital suggesting bacterial transmission. This study demonstrated that K. pneumoniae could contaminate diverse surfaces, and the persistence allowed for dissemination within the public hospital environment. The study's findings highlighted the importance of regularly monitoring hospital surfaces and emphasised on the need to strengthen current infection prevention and control (IPC) measures in hospitals to reduce the spread of bacteria.