Epidemiological and genetic characteristics of clinical carbapenem-resistant Acinetobacter baumannii strains collected countrywide from hospital intensive care units (ICUs) in China

Abstract

Acinetobacter baumannii is one of the key Gram-negative pathogens that can cause serious nosocomial infections. In China, a large proportion of clinical A. baumannii strains are multidrug resistant, among which strains resistant to carbapenems are particularly worrisome, as infections caused by such strains may limit the choice of existing antibiotics. We conducted a nationwide and genome-based surveillance on the prevalence and antibiotic susceptibility profile of carbapenem-resistant A. baumannii (CRAB) strains collected from intensive care units (ICUs) in hospitals in different provinces and investigated the routes of transmission and mechanism of resistance by whole-genome sequencing and phylogenetic analysis. We found that CRAB strains were prevalent in 71.4% (55/77) of the ICUs surveyed. Clonal spread of CRAB was found in 37.6% (29/77) of ICUs and a total of 22 different clones were identified. Most clones were transmissible within one ICU, but up to six clones could be detected in at least three hospitals. In addition, carbapenem-hydrolysing class D β-lactamases (CHDL) were found to be mainly responsible for carbapenem-resistance in A. baumannii and the ST2 global-clone is the predominant type of CRAB in China. Importantly, we found that CRAB isolates currently exhibited an extremely low rate of resistance to colistin (0.4%) and tigecycline (2.5%), but a high rate of resistance to ceftazidime–avibactam (70.2%). Findings in this work shall facilitate development of appropriate antimicrobial regimens for treatment of CRAB infections. Further surveillance and research on the evolutionary and epidemiological features of clinical CRAB strains are necessary.

Epidemiological Characteristics and Antimicrobial Resistance Changes of Carbapenem-Resistant Klebsiella pneumoniae and Acinetobacter baumannii under the COVID-19 Outbreak: An Interrupted Time Series Analysis in a Large Teaching Hospital

“…Children with low body weight and incomplete immune systems are more susceptible to the invasion of external pathogens and nosocomial infection [ 13 ]. Additionally, limited types of antibiotics are available for children, so cephalosporins, carbapenems, and macrocyclic lipids are widely used, which may lead to drug resistance [ 14 ] The resistance rates of CRKP and CRAB were also found to be higher in the ICU compared with other departments, which is in line with previous research findings [ 2 , 15 , 16 , 17 ]. In developed countries, over 20% of nosocomial infections occur in the ICU [ 18 ], where patients are at a higher risk of MDRO infection due to low organ function; comprised immunity; and underlying diseases such as diabetes, chronic obstructive pulmonary disease, and chemotherapy [ 4 ].…”

Gastrointestinal Colonization of Carbapenem-Resistant Acinetobacter baumannii: What Is the Implication for Infection Control?

“…In China, CRAB strains were prevalent in 71% of the 77 ICUs recruited for nationwide surveillance. Clonal spread of CRAB was found in 38% of the ICUs surveyed, with a total of 22 different clones identified [ 4 ]. During the COVID-19 pandemic, the risk of CRAB co-infection or secondary infection increased among the patients hospitalized with COVID-19 [ 5 ].…”

Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infection

“…In addition, they also help in adherence to host epithelial cells (Brossard and Campagnari, 2011). The protein is prevalent in A. baumanni strains including clinical and avirulents strains collected from different geographical regions (Liu et al, 2022). A study confirmed the involvement of Bap in modulation of cell surface hydrophobicity(CSH) which further support bacterial adherence to epithelial cells (Brossard and Campagnari, 2011).…”