Title : Carbapenemase-producing multidrug resistance of gram negative bacilli causing bacteremia at the general hospital of Mexico during the Covid-19 pandemic

Abstract:

Bloodstream infections due to Gram-negative bacilli is a highly consequential nosocomial infection with serious consequences and even more so because the organisms are usually highly resistant to antimicrobials. The aims of this study were to describe incidence of bacteremia caused by Gram-negative ESKAPE bacteria during COVID-19 pandemic, the clinical and microbiological characteristics, and the antimicrobial resistance (AMR). A total of 115 Gram-negative ESKAPE isolates were collected from patients with nosocomial bacteremia in a tertiary care center in Mexico between January – December 2020. A. baumannii (34%) and K. pneumoniae (28%) were the most frequent followed by P. aeruginosa (23%) and Enterobacter spp (16%). A. baumannii showed the highest levels of AMR (100%), followed by K. pneumoniae (87%), Enterobacter spp (34%) and P. aeruginosa (20%). Furthermore, the 27 K. pneumoniae isolates resistant to beta-lactams carried the blaCTX-M-15 and blaTEM-1 genes, while 33/39 A. baumannii isolates were carriers of the blaTEM-1 gene. In isolates resistant to carbapenems, 29/39 A. baumannii were carriers of blaOXA-398 and 4 of blaOXA-24. In P. aeruginosa, only one isolate was a carrier of the blaVIM-2 gene, while the 2 K. pneumoniae and 1 Enterobacter spp carried the blaNDM gene. Among colistin-resistant isolates mcr-1 gene was not detected. The clonal relatedness assessed by pulsed-field gel electrophoresis (PFGE) and by multi-locus sequence typing (MLST) demonstrated two outbreaks caused by A. baumannii ST208 and ST369 and a genetic diversity for K. pneumoniae, P. aeruginosa and Enterobacter spp. Remarkably, the ST136 and ST208 belonged to the clonal complex CC92 and IC2. A. baumannii was associated with a high mortality rate of 72%, mainly in patients with COVID-19 75% cared for in the Respiratory Ward. There was no statistically significant association between MDR profile of Gram-negative bacteria and in COVID-19 and non-COVID-19 patients. In summary, the results points to the important role of Gram-negative MDR causing bacteremia in nosocomial settings before and during the COVID-19 epidemic. In addition, the COVID-19 pandemic had no local impact on antimicrobial resistance rates in the short term. Already publish Gram-negative ESKAPE bacteria bloodstream infections in patients during the COVID-19 pandemic.

Biography:

Dr. Silvia Giono Cerezo holds a PhD in Microbiology and is a Professor at the National School of Biological Sciences (ENCB), National Polytechnic Institute (IPN), Mexico, where she teaches undergraduate and graduate courses. Her research focuses on microbiological diagnosis and molecular exploration of infectious pathogens. From 2016 to 2020, she conducted research on the identification of Chlamydia trachomatis genotypes in newborns with respiratory distress and conjunctivitis, analyzing 79 of 353 bronchial aspirate samples from neonates with a previous diagnosis of C. trachomatis infection. She also worked on a research project involving the molecular exploration of Mycoplasma fermentans and Mycoplasma genitalium in Mexican women with cervicitis, based on 243 cervicovaginal samples collected in Mexico City between September 2022 and March 2023. Her academic contributions also include the 2026 publication by Rivera et al., “Photographic Collection of Mycoplasmas: A Research Tool,” published in Enfermedades Infecciosas y Microbiología, 46(2), 81–85.