Epidemiologia molecular de carbapenemases em bacilos gramnegativos isolados de um hospital de ensino da região norte do Ceará

Abstract

The prevalence of carbapenemases production, although widespread in different countries, varies according to the regions of the world. The carbapenemases VIM, NDM, KPC, OXA-48 and IMP are the most commonly found in health centers, thus limiting therapeutic options. The aim of this study was to determine the molecular epidemiology of carbapenemases in gramnegative bacilli (GNB) isolated from a teaching hospital in the northern region of Ceará, isolated between February 2023 and September 2024. A total of 72 GNB were evaluated, the identification and sensitivity profile of these isolates were performed in the microbiology laboratory of the aforementioned hospital using the automated VITEK®2 system. The specimens were then sent to the Ceará Central Laboratory (LACEN) in Fortaleza, CE, where the Xpert ® Carba-R test by real-time multiplex PCR was performed to detect the genetic sequences of blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP-1. Regarding the isolation sites, a higher frequency was observed in urine (n = 30; 41.6%), followed by blood (n = 21; 29.1%) and tracheal aspirate (n = 16; 22.2%). In addition, most GNB were isolated from the Intensive Care Units (n = 32; 44.4%), followed by the Neurology sector (n = 14; 19.4%) and Surgical Clinic (n = 8; 11.1%). Among the carbapenemase-producing microorganisms, the highest prevalence of detection in the analyzed period was in Klebsiella pneumoniae (n = 30; 41.6%), followed by Acinetobacter baumannii (n = 20; 27.7%) and Pseudomonas aeruginosa (n = 9; 12.50%). All specimens analyzed were resistant to Imipenem, Meropenem and Ertapenem, except. A. baumannii that only 13 (65.0%) of the 20 isolates showed resistance to Ertapenem. Regarding the other antimicrobials tested, the majority were resistant to third-generation cephalosporins, and the only isolate of Serratia marcescens was resistant to all antimicrobials analyzed. The blaNDM gene was detected in 15 (50.0%) of the K. pneumoniae isolates, in 4 (100%) of Klebsiella aerogenes, in 2 (66.7%) of Providencia stuartti and in 1 (20.0%) of Proteus mirabilis. On the other hand, the blaKPC gene was found in 16 (53.3%) isolates of K. pneumoniae, in 3 (33.3%) of P. aeruginosa and in the isolate of S. marcescens. Furthermore, 3 (10%) of K. pneumoniae simultaneously harbored the blaKPC e blaNDM genes. Regarding the clinical outcome of patients infected with these carbapenemase-producing bacilli, 39 (54.1%) were discharged from hospital, and of these, 11 (28.2%) were isolated from GNB with blaNDM resistance genes and 9 (23.0%) with blaKPC. However, 33 (45.8%) died, of which 10 (30.3%) were found with blaKPC, 7 (21.2%) with blaNDM, and 1 (3.0%) was isolated with bacteria that contained both the blaKPC and blaNDM genes. Therefore, the results of this study reveal a predominance of NDM and KPC carbapenemases among the GNB isolated from this teaching hospital. This fact corroborates, at a local level, the worrying dissemination of these βlactamases both nationally and globally, as well as the predisposition of bacteria that carry these genes to cause healthcare-related infections, given their ability to accumulate and transfer resistance mechanisms.