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Published on: May 4, 2018
Carbapenem-resistant Pseudomonas aeruginosa strains: a worrying health problem in intensive care units
Gleyce Hellen de Almeida de Souza1, Luana Rossato1, Gabriel Teixeira Brito1
1Universidade Federal da Grande Dourados, Laboratório de Pesquisa em Ciências da Saúde, Dourados, Mato Grosso do Sul, Brazil.
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 cost of hospitalization for the public health system. Therefore, the evolution of this resistance and its dissemination should be actively monitored among critically ill patients to improve their health conditions.
Insights
Carbapenem-resistant Pseudomonas aeruginosa in ICUs poses a significant threat, leading to high mortality and healthcare costs. Monitoring resistance mechanisms is crucial for patient care.
Area of Science:
- Clinical microbiology
- Infectious diseases
- Public health
Background:
- Pseudomonas aeruginosa is a common cause of hospital-acquired infections.
- Intrinsic resistance to antibiotics necessitates carbapenem use.
- Emergence of carbapenemases in P. aeruginosa is a critical public health concern.
Purpose of the Study:
- To characterize carbapenem-resistant P. aeruginosa strains from ICU patients.
- To investigate molecular and epidemiological features of resistance.
- To assess clinical outcomes and economic impact.
Main Methods:
- Broth microdilution for antimicrobial susceptibility testing.
- PCR and DNA sequencing for resistance gene detection.
- SDS-PAGE and PCR for outer membrane protein analysis.
Main Results:
- blaKPC-2, blaTEM, and blaSHV genes were detected in a subset of isolates.
- OprD porin deficiency was observed, but without detectable mutations.
- High rates of sepsis, respiratory failure, and mortality (39%) were noted.
- Extended hospitalization (average 34.6 days) and high costs were associated with these infections.
Conclusions:
- Carbapenemase production was not the primary resistance mechanism in this cohort.
- OprD porin alterations likely contribute to carbapenem resistance.
- Carbapenem-resistant P. aeruginosa in ICUs leads to severe patient outcomes and substantial healthcare costs.
- Active surveillance of resistance in critically ill patients is essential.
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