Evaluating the Saliva of Burn ICU Patients for Resistant Infections Harbor Metallo-β-Lactamase Genes.

Pseudomonas aeruginosa and Acinetobacter baumannii are the bacteria which increasingly account for nosocomial infections. Due to high virulence, the rate of Multi-Drug Resistance (MDR) and limited availability of new agents, these infections create significant clinical burdens, making it important to identify the possible sources of their occurrence. The aim of this study was to assess non-lactose fermenting bacteria and their metallo-β-lactamase (MBLs) genes expression in the Burn Intensive Care Unit (BICU) patients' saliva samples. This cross-sectional study was conducted from 2017 to 2018 on 124 saliva samples of BICU patients. Identified isolates were evaluated for drug susceptibility by disc diffusion method. MBLs production isolates were detected by Modified Hodge test and Imipenem-EDTA Combined disk. MBLs related genes were evaluated by polymerase chain reaction (PCR). A total of 86 Gram negative non-lactose fermenting bacteria (38; A. baumannii) and (48; P. aeruginosa), were detected. All of the A. baumannii isolates were resistant to Carbapenems, while more than 90% of them were sensitive to Colistin. However, the highest sensitivity in P. aeruginosa isolates was related to Carbapenems and Colistin. More than 95% of A. baumannii and 32% of P. aeruginosa were detected MDR. MBLs production was confirmed in 9 (33.33%) P. aeruginosa and 18 (66.67%) A. baumannii isolates. The blaVIM was the most prevalent gene, while this gene was detected in all of MBLs positive strains. This study confirmed the prevalence of carbapenemase producer Gram-negative bacilli in the saliva of BICU patients. The results of the present study provide a new data set about saliva infection source that could lead to the proper antibiotic regimen and better control of drug resistance.