Community Origin and Previous Use of Antimicrobials Increase the Risk of Nosocomial Multidrug-resistant Bacteria Colonisation in the Intensive Care Unit in a Brazilian Hospital

Hospitalised patients are often surrounded by microorganisms, and antibiotic-resistant pathogens are a major and growing threat to public health.

This study aimed to investigate the epidemiology and the risk factors for colonisation by multidrug-resistant organisms (MDROs) in a Brazilian hospital.

Patients in the Intensive Care Unit (ICU) who underwent nasal and rectal swab cultures for the surveillance of colonisation by MDROs were evaluated in a retrospective study. MDROs were determined by routine microbiological cultures.

Of the 785 patients included in this study, 86 presented positive results for MDRO colonisation. Overall, the most frequently isolated organism was Klebsiella pneumoniae (41.9%), followed by Escherichia coli (33.7%). The main type of resistance was the production of extended-spectrum beta-lactamases (ESBL). The prevalence of MDRO infections was significantly associated with the patient's origin (community or hospital-acquired). Having been submitted to previous antimicrobial drug therapy was significantly associated with MDRO infection (relative risk [RR]: 4.02 [2.60 - 6.23]).

MDRO ICU colonisation was variable, with similar frequencies as other centres, and important factors, including previous hospital stay and antibiotic use, were closely related to MDRO colonisation. Therefore, control interventions should reduce their rates, especially considering the particularities of each geographic centre.