ObjectivesTo detect the admission rate and hospital acquired rate of carbapenem-resistant Klebsiella pneumoniae (CRKP) and carbapenem-resistant Acinetobacter baumannii (CRAB) of active surveillance in Emergency Intensive Care Unit patients of West China Hospital of Sichuan University, to examine whether rectal colonization of CRKP and CRAB are associated with nosocomial infection, so as to provide a scientific basis for the prevention and control of CRKP and CRAB.MethodsA nested case-control study was conducted between April and September 2018 in Emergency Intensive Care Unit. Rectal swabs were obtained to screen CRAB and CRKP, and the admission rate of colonization was calculated. According to whether infected with CRKP/CRAB, the patients were divided into case group (infection group) and control group (noninfection group) to determine whether colonization of CRKP/CRAB were independent risk factors for nosocomial infection using logistic regression model.ResultsThe admission rate of CRKP and CRAB patients were 4.08% (18/441) and 8.78% (38/433), and the nosocomial infection rate was 3.63% (16/441) and 18.01% (78/433) separately. Multivariate analysis showed that rectal colonization of CRKP [odds ratio=5.438, 95% confidence interval (1.643, 17.999), P=0.006] was an independent risk factor for nosocomial infection. However, there was no statistical correlation between rectal colonization of CRAB and nosocomial infection [odds ratio=1.449, 95% confidence interval (0.714, 2.942), P=0.305].ConclusionsThe rectal colonization rate of CRAB is higher than that of CRKP, but it does not increase the risk of CRAB infection in patients. Rectal colonization of CRKP is an important factor for infection of patients. Therefore, early detection of CRKP through active surveillance and taking control measures can help reduce the risk of its spread in the hospital.
Objective To investigate antimicrobial resistance profiles of carbapenem-resistant Enterobacter spp. (CREn) and the bactericidal effects of aztreonam combined with avibactam. Methods The CREn strains isolated from the West China Hospital of Sichuan University between 2016 and 2021 were identified by gyrB gene amplification and subsequent sequencing. The drug sensitivity results, sample types and distribution of relevant patient departments of these strains were summarized. Colistin-resistant and -intermediate strains were selected to carry out the bactericidal test of colistin and aztreonam combined with avibactam. Results A total of 110 clinical strains of CREn were included. The most common strain was Enterobacter xiangfangensis (91 strains), the highest proportion was in the intensive care unit (27.27%), and the proportion of respiratory tract samples was more than 40%. The antimicrobial sensitivity results showed that CREns were all resistant to carbapenems, the resistance rate to colistin was 23.64%, and the resistance rate to aztreonam combined with avibactam was 0. Among other antimicrobial agents, the antimicrobial resistance rate of amikacin and tigecycline were less than 10%. The time-kill curve showed that for colistin-intermediate strains, colistin could achieve bactericidal effect in a shorter time than aztreonam combined with avibactam. However, whether the strain was resistant to colistin or not, the bactericidal rate of 2 μg/mL aztreonam combined with avibactam in 24 hours could exceed 99%. Conclusion CREn is resistant to most commonly used clinical antibacterial drugs, but remains sensitive to aztreonam combined with avibactam, and aztreonam combined with avibactam has bactericidal effect on it.