The incidence of intestinal colonization of carbapenem-resistant Enterobacterales and its risk factors for bloodstream infection / 中华检验医学杂志

ABSTRACT

Objective:The aim of this study was to determine the colonization rate of carbapenem-resistant Enterobacterales (CRE) and identify the proportion and risk factors for bloodstream infection.Methods:This was a retrospective study conducted at the Department of Clinical Laboratory, Peking University People′s Hospital from January 2018 to December 2021. A total of 4 993 patients underwent rectal swab CRE screening for CRE, of which 137 were found to be positive. Clinical and laboratory data of the positive patients were collected, and the following parameters were analyzed the positive rate of CRE screening in high-risk population, the species of colonized bacteria, antimicrobial resistance and the risk factors of CRE bloodstream infection in colonized patients. Statistical analysis was performed using SPSS 26.0 software. Univariate analysis was conducted using the chi-square (χ 2) test, while multivariate analysis was performed using binary logistic regression. The results were expressed as relative risk (odds ratio, OR) and 95% confidence interval ( CI). A significance level of 0.05 was considered statistically significant. The drug resistance rate of pathogen was analyzed by WHONET 5.6 software. Results:During the study period, a total of 4 991 patients who underwent rectal swab screening were eligible for inclusion, of which 137 patients were screened positive, resulting in a positive rate of 2.7% (137/4 991). The positive rates were higher in the intensive care ward and hematology ward, with rates of 5.5% (27/493) and 3.3% (109/3 321), respectively. A total of 145 colonization strains were isolated from patients with positive CRE screening, including 63 strains of Klebsiella pneumoniae (43.4%, 63/145), 52 strains of Escherichia coli (35.9%, 52/145), 16 strains of Enterobacter cloacae (11.0%, 16/145) and 14 strains of other Enterobacterales (9.7%, 14/145). The metal β-lactamase production type was the main component of CRE positive colonizing bacteria. The antimicrobial resistance of 145 strains to 22 antibacterial agents revealed that amikacin and tigacycline were the most sensitive. Among 137 CRE screening-positive patients, 14 (10.2%, 14/137) developed bloodstream infection. The isolated pathogenic bacteria included 10 Klebsiella pneumoniae strains and 4 Escherichia coli strains, with a predominant serine carbapenemase producing. Notably, the enzyme type and antimicrobial resistance of the bloodstream infection isolates in the same patient were highly consistent with those of the previous screening strains. Comparison was made between patients with positive CRE screening and those with CRE conversion to bloodstream infection. The unifactor analysis revealed significant differences in surgical history, neutropenia, hematopoietic stem cell transplantation, history of antibiotic use before rectal swab screening, screening within 48 hours after admission, and serine carbapenemase production by strains ( P<0.05). The multivariate analysis indicated that surgical history ( OR 24.659, 95% CI 2.540-239.411, P=0.006) and neutropenia ( OR 93.796, 95% CI 6.294-1 397.804, P=0.001) remained significantly associated with the risk of CRE bloodstream infection ( P<0.05). Conclusions:The CRE colonization rate was low in our hospital, but the proportion of patients with positive screening converted to bloodstream infection was high. Surgical history and neutropenia are risk factors for bloodstream infection transmission. Thus, it is essential to enhance monitoring in high-risk areas and susceptible patients.