Prevalent Dominant Acinetobacter baumannii ST191/195/208 Strains in Bloodstream Infections Have High Drug Resistance and Mortality

Abstract

Background

Different sequence types of Acinetobacter baumannii (AB) have their own epidemiological characteristics, drug resistance, and toxicity.

Methods

AB bloodstream infection (BSI) in the First Affiliated Hospital of Medical College of Zhejiang University from January 2012 to December 2017 were classified by multilocus sequence typing. Clinical data of patients were retrospectively analyzed, drug resistance and toxicity were respectively studied by drug sensitivity and complement killing tests.

Results

247 unduplicated AB strains were collected, and ST191/195/208, the main epidemic dominant strain, accounted for 70.9%. Patients with ST191/195/208 on infection had higher white blood cell (10.8 vs 8.9, p = 0.004), neutrophil% (89.5 vs 86.9, p = 0.005), neutrophil count (9.5 vs 7.1, p = 0.021), D-dimer (6.7 vs 3.8, p = 0.000), total bilirubin (27.0 vs 21.5, p = 0.038), pronatriuretic peptide (324 vs 164, p = 0.042), C-reactive protein (82.5 vs 56.3, p = 0.048), clinical pulmonary infection score (CPIS; 7.33 ± 2.30 vs 6.50 ± 2.72, p = 0.045), and acute physiology and chronic health evaluation-II (APACHE-II; 19.620 ± 5.1850 vs 17.648 ± 6.1251, p = 0.011). Patients with ST191/195/208 had more complications, including pulmonary infection (p = 0.041), septic shock (p = 0.009), and multiple organ failure (p = 0.019). Patients with ST191/195/208 had higher 3 day mortality (24.6% vs 13.9%, p = 0.043), 14 day mortality (46.8% vs 26.8%, p = 0.003), and 28 day mortality (55.0% vs 32.4%, p = 0.001). ST191/195/208 strains had higher drug resistance to most antibiotics, and higher survival rate at 90% normal serum concentration (p < 0.001).

Conclusion

ST191/195/208 strains predominate in the hospital and prevails in patients with severe infections with increased multidrug antimicrobial resistance and excessive mortality compared to any other AB stains.

Keywords:

• Acinetobacter baumannii
• bloodstream infection
• MLST
• mortality
• toxicity

Ethics/Copyright

This study complied with the declaration of Helsinki and all methods were performed in accordance with the relevant guidelines and regulations of the Ethics Committee of the First Affiliated Hospital of Zhejiang University (batch number: 2017-699). This study used data collected from patient records while maintaining patient anonymity. Because this study presented no more than minimal risk of harm to patient subjects, the institutional review board approved a waiver of patient informed consent.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Key Research and Development Program of China (2021YFC2300302); Zhejiang Provincial Natural Science Foundation of China under Grant (LQ21H190001); Medical Science and Technology Project of Zhejiang Province (No.2020KY735). Hangzhou Medical and Health Science and Technology Project (A20210054); Hangzhou Chest Hospital affiliated to Zhejiang University Medical College and Zhejiang University Medical College Joint pre-research project (ZAYY2).