Carbapenem-resistant Pseudomonas aeruginosa strains: a worrying health problem in intensive care units

• Published in: Revista do Instituto de Medicina Tropical de São Paulo
• Main Authors: Gleyce Hellen de Almeida de Souza, Luana Rossato, Gabriel Teixeira Brito, Graciela Mendonça dos Santos Bet, Simone Simionatto
• Format: Article in Journal/Newspaper
• Language: English
• Published: Universidade de São Paulo (USP) 2021
• Subjects: Healthcare-associated infections; Antimicrobial resistance; Public health; Carbapenemase; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1590/s1678-9946202163071; https://doaj.org/article/2716f2a4d2c4474db97f1c68aaeb837b

ABSTRACT Pseudomonas aeruginosa is one of the most common bacterium with a broad spectrum of human-associated infections. It is intrinsically resistant to many antimicrobial drugs, making carbapenems crucial in clinical management. The emergence and dissemination of carbapenemases among P. aeruginosa clinical isolates is a serious public health concern as it limits the options for the treatment of bacterial infections. Here, we described the molecular and epidemiological characteristics of 28 carbapenem-resistant P. aeruginosa strains isolated from patients hospitalized in an intensive care unit (ICU). The antimicrobial susceptibility of carbapenem-resistant P. aeruginosa strains was determined by broth microdilution. The presence of resistance genes was evaluated by PCR and DNA sequencing. Additionally, alterations in genes encoding P. aeruginosa outer membrane proteins were analyzed by PCR as well as SDS-PAGE. Clinical characteristics of the patients and the economic impact of hospitalization on the public health system were evaluated. PCR amplification showed that the blaKPC-2 and blaTEM genes were identified in three isolates (11%) and blaSHV gene in two isolates (7%). Outer membrane profiles obtained by SDS–PAGE indicated that the OprD porin was either absent or was produced at very low levels. A PCR assay using oprD-specific primers failed to show the presence of mutations in this gene. P. aeruginosa strains were isolated from 28 patients, among whom 43% (12/28) had sepsis, 31% (9/28) had respiratory failure, and 31% (9/28) had systemic arterial hypertension. A high mortality rate (39%) was observed in these patients, with an average duration of hospitalization of 34.6 days and a median cost of 3.275 dollars per patient. The production of carbapenemase was not the main mechanism of resistance in these strains. All carbapenem-resistant P. aeruginosa were isolated from patients hospitalized in the ICU. Besides the high mortality rate, many patients remained hospitalized for several days, resulting in a high ...