Brazilian Study on the Prevalence of Carbapenemase Producing Organisms and Their Relation with Patients’ Death Rate

Aims: Determine the clinical characteristics of patients and the microbiological characteristics of the isolated Gram-negative microorganisms; Analyze the relationship between hospitalization sectors and the occurrence of bacteria resistant to carbapenems; Determine the prevalence of Gram-negative in clinical sectors of a University Hospital from Fortaleza, Brazil; Relate the prevalence to resistent Gram-negative bacteria with patients’ death rate.

Study Design: This is a descriptive, retrospective and cross-sectional study, carried out between January and December 2022 at a university hospital in Fortaleza, Brazil.

Place and Duration of Study: Microbiology Sector of the Central Laboratory of the Walter Cantídio University Hospital between January 2022 and December 2022.

Methodology: All reports that showed a positive culture for Gram-negative bacilli and that carried out antibiotic sensitivity testing were included in the study. Their identification (ID) and the Antibiotic Sensitivity Test (TSA) were carried out using the automated system VITEK® 2 (BioMérieux®, Marcyl’Etoile, France), which uses the OBSERVA system for data archiving. The data was collected on a specific form and collected through patient reports issued by the hospital system. The forms were reviewed by a microbiologist pharmacist from the microbiology service. The data were analyzed and audited in the Excel® program for statistical validation using the SPSS Statistics® program, version 17.0.

Results: 398 samples positive for Gram-negative microorganisms were collected. These samples referred to 236 patients admitted to different sectors of the hospital. It was seen that the Surgical Center concentrated a greater number of patients, representing 66 individuals (28%). The most frequently isolated species (n=217) were Klebsiella pneumoniae (n= 70; 23%) and Pseudomonas aeruginosa (n= 70; 23%), followed by Escherichia coli (n= 43; 14%) and Acinetobacter baumannii (n = 34; 11%), respectively. It was observed that 29.9% of GNB were isolated from blood samples, this being the most prevalent biological site. Bloodstream infection (BSI) was identified as the biological site with the highest number of cases, recording 65 (29.9%) positive isolates in the blood. It was found that 131 isolates of Gram-negative bacteria presented resistance mechanisms, with resistance to carbapenems being the most prevalent, corresponding to 42.75% of cases originating from enterobacteria. It was found that admission to the adult ICU increases the chances of death by 6.017 (OR) times in patients who isolated carbapenem-resistant GNBs (p <0.001).

Conclusion: The study analyzed the microbial profile of patients at a university hospital, identifying a significant association between death and microbial resistance, especially with Klebsiella pneumoniae. Bloodstream infections were frequent, being the site with the highest number of cases. The predominant resistance mechanism was Carbapenem-Resistant Enterobacteriaceae (CRE). The results highlight the need for continuous monitoring and control of antimicrobial resistance to guide epidemiological strategies.