DISTRIBUTION OF ANTIMICROBIAL-RESISTANT GRAM-NEGATIVE BACTERIA IN THE HOSPITAL ENVIRONMENT OF AN ONCOLOGY CENTER IN BANGKOK, THAILAND

Abstract

Antimicrobial resistance (AMR), particularly among Gram-negative bacteria, poses a significant threat to patient safety in healthcare settings. Hospital environments may serve as reservoirs for antimicrobial-resistant organisms, especially in high-risk areas such as oncology wards. This study investigated the prevalence and distribution of antimicrobial-resistant Gram-negative bacteria on environmental surfaces in inpatient wards of an oncology center in Bangkok, Thailand. A cross-sectional study was conducted between January and March 2024. A total of 288 environmental surface samples were collected from patient rooms, patient zones, and healthcare zones, including high-touch and low-touch surfaces. Samples were enriched in tryptic soy broth and cultured on blood agar and MacConkey agar. Bacterial identification was performed using MALDI-TOF MS, and antimicrobial susceptibility testing was conducted using the Kirby-Bauer disk diffusion method according to CLSI guidelines. Bacterial contamination was detected in 98.61% of samples following enrichment. Gram-negative bacteria were detected across all ward zones, with higher recovery from moisture-prone and frequently touched surfaces. Seventy-five Gram-negative isolates were included in resistance analysis. Carbapenem resistance was identified exclusively among Enterobacterales, detected in Klebsiella spp. (20.0%) and Enterobacter spp. (10.0%). No carbapenem resistance was observed among non-fermenting Gram-negative bacilli. In conclusion, antimicrobial-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacterales, were present on environmental surfaces in inpatient oncology wards. These findings highlight the importance of environmental surveillance and targeted infection prevention and control strategies in oncology settings.