Balance in the gut microbiota (GM) provides benefits to the host; however, during hospitalization, with the use of antimicrobials, there is an imbalance in the GM, leading to a worse prognosis for the patient. The objective was to evaluate the frequency of carriage of more than one bacterial species and/or more than one resistance mechanism in patients during hospitalization.

This is a retrospective study (08/14 to 07/25), conducted in a teaching hospital in Paraná. The analysis was based on molecular detection by multiplex PCR of carbapenemase genes (CG) in Gram-negative bacteria (GNB). Patients were included if they had positive rectal swab surveillance cultures (PRSSC) for at least two GNB of the same species (GNB=E) carrying different genes (CG#), or GNB of different species (GNB#E) carrying different CG (CG#) or the same genes (CG=). Isolates were identified by the automated Phoenix-BD system. All identification and susceptibility testing data were retrieved from the Epicenter system.

During the analyzed period, a total of 1,207 isolates carrying CG from 948 patients were recovered. Of these, 112 patients with 233 PRSSC were included in the study. The detected CG were blaNDM (64%), blaKPC (31%), blaSPM and blaVIM (1% each). The main isolates were: Klebsiella pneumoniae-Kp (49%), Escherichia coli-Ec (16%), Pseudomonas aeruginosa-Pa (16%), Acinetobacter baumannii-Ab (6%) and Enterobacter cloacae (4%). Ninety-six patients had PRSSC for GNB#E: 52 patients with two isolates carrying blaNDM, 24 patients with two isolates carrying blaKPC, 16 patients with GNB#E carrying CG# (one blaNDM and another blaKPC), and another 4 patients with GNB#E carrying CG#: 1 with metallo-type (blaVIM, blaIMP, blaSPM and blaNDM+blaKPC) together with another isolate carrying blaKPC. In 10 patients, 20 GNB=E carrying CG# (10 blaKPC and 10 blaNDM) were recovered, all from the genus Klebsiella. We highlight the presence of PRSSC in six patients with three GNB#E in the same patient, all carrying blaNDM. Kp was the most frequently isolated species, recovered in PRSSC from 105 patients, and blaNDM was the most detected CG across a greater diversity of species.

The data demonstrate the presence of up to three multidrug-resistant GNB#E carrying different carbapenemases in the same patient, confirming that the GM is a reservoir of resistance genes and that surveillance cultures are extremely important for monitoring and controlling the dissemination of these genes.