Evaluation of Carbapenem-resistant Enterobacteriaceae infections and the rate of which colonization switch into infection.

Objectives: Carbapenem-resistant Enterobacterales (CRE) infections have limited treatment options, and these infections are associated with high mortality rates. Asymptomatic carriers colonized with CRE contribute to the spread of CRE in hospitals. It was aimed to determine the frequency of CRE isolates detected in our center, carbapenemase ratios in these strains, carbapenemase genes, antibiotic resistance profiles, rectal CRE colonization rates and to evaluate various clinical features of CRE infections. Methods: Enterobacterales species isolated from various specimens and Enterobacterales species isolated from rectal swab specimens sent for colonization screening were examined. Patients with CRE colonization in rectal swab samples were examined for the development of CRE infection at a later time. CRE isolates were examined for carbapenemase production and the presence of carbapenemase gene. Results: 12,721 Enterobacterales (10,161 E. coli and 2395 K. pneumoniae, 165 Citrobacter) isolates were examined. Carbapenem resistance was detected in 10.3% of these strains. CRE was detected in 4.7% of 15695 rectal swab samples evaluated for colonization. In 23.4% of the patients with CRE colonization, CRE growth was detected in other samples besides the rectal swab in the later period. It was observed that CRE infections developed on average 21 days after colonization. Conclusion: CRE infections have started to emerge as a factor not only in hospitalized patients but also in community-acquired infections. Our study also showed that CRE colonization could be a significant risk factor for the development of infection. Therefore, early screening detection to detect colonization can help prevent or limit CRE infections with appropriate isolation methods.