Estudo da diversidade genômica associada à resistência antimicrobiana de baci-los gram-negativos não fermentados isolados de pacientes internados no hospital regional norte em Sobral

Abstract

Health care-associated infections (HAIs) are those that appear during the patient's hospitalization and were not present or incubating at the time of admission, they are usually produced by microorganisms with multiple resistance to antibiotics, among which nonfermentative gram-negative bacilli (NF-GNB), such as Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia. Therefore, the aim of this research was to carry out a genomic study to identify the bla-KPC2, bla-oxa143 and mcr-1 genes responsible for patterns of antimicrobial resistance in NF-GNB isolated from HAIs at the North Regional Hospital (NRH) in Sobral - CE. The collection of microbiological samples took place from March 2021 to March 2022, the identification and sensitivity profile of the NF-GNB were performed by the VITEK®2 automated system at the São Carlos laboratory in Fortaleza - CE, NRH's reference laboratory. The isolates were collected from clinical samples of blood, respiratory tract infections, catheter tip and urine. Confirmation of bacterial identity and genomic analysis was performed using molecular biology techniques at the UFC microbiology laboratory in Sobral. We found that during the study period, 119 NF-GNB of patients with HAI were identified at the NRH, with P. aeruginosa (n=51; 42.9%), A. baumannii (n=48; 40.3%) and S. maltophilia (n=20; 16.8%). A higher prevalence of HAI due to A. baumanni (58.4%) was observed in male patients and S. maltophilia (65%) in female patients. Of the total NF-GNB, only 59 (49.5%) were characterized in relation to resistance genes. Of these, 20 (33.8%) were A. baumannii, with 12 (60%) harboring the bla-KPC2 and bla-oxa143 genes and 3 (15%) the mcr-1 gene; of the 20 isolates of P. aeruginosa analyzed, in 9 (45%) bla-KPC2 and bla-oxa143 were identified and in 3 (15%) mcr-1, and of 19 specimens of S. maltophilia, 9 (47 .3%) had the bla-KPC2 and 10 (52.7%) had the bla-oxa143. It was also observed that all strains of P. aeruginosa were resistant to gentamicin, cefepime, piperacillin+tazobactan, tigecycline and trimethoprim/sulfamethazole and showed a variable resistance pattern for the other antimicrobials tested. On the other hand, all A. baumannii isolates also showed resistance to piperacillin+tazobactan and tigecycline, in addition to meropenem and imipenem. Whereas most strains of S. matophilia were resistant to levofloxacin and trimethoprim/sulfamethazole. Regarding the clinical outcome of the patients, it was found that 58.9% of the patients infected by these microorganisms died. Therefore, the results of this study indicate that P. aeruginosa and A. baumannii are among the main causes of HAI due to NF-GNB in the NRH, in addition most of them are multidrug resistant and harbor the bla-KPC2 and bla-oxa143 resistance genes reinforcing the idea of how important it is to know the local epidemiology so that, based on it, it is possible to work in an integrated manner with the Hospital Infection Control Service to develop adequate guidelines and targeted therapeutic regimens, aiming to reduce the frequency of HAIs and obtain a better prognosis for patients.