Genomic relatedness and dissemination of among isolated from hospital environments and clinical specimens in Thailand.

BACKGROUND

() is an important cause of nosocomial infection, especially in intensive care units (ICUs). It has the propensity to tolerate various environments and multiple classes of antibiotics. Our study aimed to characterize the comparative genomes of from hospital environments and clinical isolates.

METHODS

Clinical and environmental isolates were collected from a university hospital. Antibiotic susceptibility testing was performed, antibiotic resistance genes (ARGs) were characterized, and repetitive element palindromic-PCR (rep-PCR) typing was performed. Eight representative isolated from environmental and clinical samples from the same wards were selected for whole-genome sequencing (WGS) using the Illumina platform.

RESULTS

A total of 106 isolates were obtained from 312 hospital environmental samples. A high percentage of samples with colonization were detected from AMBU bags (77.9%), followed by bedrails (66.7%) and suction tubes (66.7%). We found that 93.4% of the environmental isolates were multidrug-resistant (MDRAB), and 44.7% were extremely drug-resistant (XDRAB). and were present in 80.2%, 78.3%, and 0.9% of all isolates, respectively. Sixty-one isolates were collected from patient specimens in the same ward. Among all clinical isolates, MDRAB and XDRAB accounted for 82% and 55.7%, respectively. The most dominant ARGs identified was (80.3%), followed by (55.7%). The genetic diversity of all isolates using rep-PCR could be divided into 33 genotypes. The genome size of eight ranged from 3.78-4.01 Mb. We found six of eight strains to be -harboring . Mobile genetic elements (MGEs), such as integron1 (1), located upstream of were observed. The phylogenomic relationship of the core and pan genomes as well as the single nucleotide polymorphism (SNP) count matrix revealed the genetic similarity of environmental and clinical strains obtained from the same ward.

CONCLUSION

This study confirmed that colonized in hospital environments were the main reservoir of nosocomial infection and provides critical information to guide the control of infection.