Association of capsular types with carbapenem resistance, disease severity, and mortality in Acinetobacter baumannii
Yu-Chia Hsieh1, Shi-Heng Wang2, Yi-Yin Chen1
1Department of Pediatrics, Chang Gung Children's Hospital, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Taoyuan, Taiwan.
Abstract:
Acinetobacter baumannii emerged as one of the most important pathogens that causes nosocomial infections due to its increased multidrug resistance. Identifying capsular epidemiology in A. baumannii can aid in the development of effective treatments and preventive measures against this emerging pathogen. Here we established a wzc-based method, and combined it with wzy-PCR to determine capsular types of A. baumannii causing nosocomial bacteraemia collected at two medical centres in Taiwan from 2015 to 2017. Among the 237 patients with A. baumannii bacteraemia, 98 (41.4%) isolates were resistant to carbapenems. Four prevalent capsular types (KL2, KL10, KL22, and KL52) accounted for 84.7% of carbapenem-resistant A. baumannii (CRAB) and 12.2% of non-CRAB. The rate of pneumonia, intensive care unit admission, APACHE II score, and Pitt bacteraemia score were higher in patients with KL2/10/22/52 infection than in those with non-KL2/10/22/52 infection. Patients with KL2/10/22/52 infection and patients with CRAB infection have a higher cumulative incidence of attributable and all-cause in-hospital 30-day mortality. On multivariate analysis, appropriate empirical antimicrobial therapy within 24 h was associated with a lower risk of 30-day attributable mortality in the KL2/10/22/52 isolates (odds ratio = 0.19, 95% CI: 0.06-0.66, p = 0.008) but not in non-KL2/10/22/52 isolates. Early recognition of carbapenem resistance-associated capsular types may help clinicians to promptly implement appropriate antimicrobial therapy for improving the outcomes in patients with CRAB bacteraemia.
Insights
Four prevalent capsular types of Acinetobacter baumannii (KL2, KL10, KL22, KL52) are linked to carbapenem resistance and worse patient outcomes. Early identification of these types can guide timely antimicrobial therapy and improve survival rates in nosocomial infections.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Acinetobacter baumannii is a significant cause of hospital-acquired infections, often exhibiting multidrug resistance.
- Understanding capsular epidemiology is crucial for developing effective treatments and prevention strategies against this pathogen.
Purpose of the Study:
- To determine the capsular types of Acinetobacter baumannii causing nosocomial bacteremia in Taiwan.
- To investigate the association between specific capsular types and carbapenem resistance, clinical outcomes, and mortality.
Main Methods:
- A wzc-based method combined with wzy-PCR was used to identify capsular types.
- Isolates were collected from patients with Acinetobacter baumannii bacteremia at two medical centers in Taiwan (2015-2017).
- Clinical data, including resistance patterns, infection severity, and mortality, were analyzed.
Main Results:
- Four prevalent capsular types (KL2, KL10, KL22, KL52) accounted for 84.7% of carbapenem-resistant Acinetobacter baumannii (CRAB) isolates.
- Patients with KL2/10/22/52 infections had higher rates of pneumonia, ICU admission, and severity scores.
- Infection with KL2/10/22/52 types and CRAB was associated with increased 30-day mortality.
Conclusions:
- Specific capsular types (KL2, KL10, KL22, KL52) are strongly associated with carbapenem resistance in Acinetobacter baumannii.
- Prompt empirical antimicrobial therapy within 24 hours improved outcomes for patients with KL2/10/22/52 infections.
- Early recognition of carbapenem resistance-associated capsular types can guide timely treatment and improve patient survival.
