Ann Lab Med.  2018 May;38(3):266-270. 10.3343/alm.2018.38.3.266.

Seasonal and Temperature-Associated Increase in Community-Onset Acinetobacter baumannii Complex Colonization or Infection

• Kim YA
• Kim JJ
• Won DJ
• Lee K

• KMID: 2403462
• DOI: http://doi.org/10.3343/alm.2018.38.3.266

Abstract

Identifying the trends in community-onset Acinetobacter baumannii complex isolation and diversity according to temperature could help provide insight into the behavior of the A. baumannii complex. We performed a retrospective analysis of A. baumannii complex (Acinetobacter baumannii, Acinetobacter nosocomialis, Acinetobacter pittii, and Acinetobacter calcoaceticus) isolates obtained from patients at a Korean community hospital from 2006 to 2015 with reference to seasonal temperatures. The incidence rates were compared between warm (June-September) and cold (November-March) months, defined as an average mean temperature ≥20℃ and ≤5℃, respectively. Incidence rate was calculated as the number of cases per month, converted to cases/10⁵ admissions for healthcare-acquired isolates and cases/10³ outpatients for community-onset isolates. Approximately 3,500 A. baumannii complex cases were identified, and 26.2% of them were community-onset cases. The median (interquartile range) number of community-onset A. baumannii complex cases was significantly higher (P=0.0002) in warm months at 13.8 (9.5-17.6) than in cold months at 10.1 (6.3-13.2). There was a strong correlation between community-onset A. baumannii complex cases and temperature (Pearson's r=0.6805, P=0.0149). Thus, we identified a seasonality pattern for community-onset A. baumannii complex colonization or infection, but not for healthcare-acquired cases.

Keyword

Acinetobacter baumannii complex; Community-onset; Seasonality

MeSH Terms

Acinetobacter baumannii*
Acinetobacter*
Colon*
Hospitals, Community
Humans
Incidence
Outpatients
Retrospective Studies
Seasons*

Figure

• 

  Fig. 1 Incidence of Acinetobacter baumannii complex cases by calendar month, along with monthly average temperatures over 10-year study period.*Number of cases were converted to cases per 103 outpatients (CO) or cases per 105 admissions (HA).Abbreviations: CO, community-onset; HA, healthcare-acquired; Temp, temperature.

• 

  Fig. 2 Correlation of Acinetobacter baumannii complex cases by calendar month, along with monthly average temperatures from 2006 to 2015. (A) Temperatures (℃) vs Community-onset (cases/103 outpatients), y=2.69x-19.43, r=0.6805, P<0.05; (B) Temperatures (℃) vs Healthcare-acquired (cases/105 admissions) y=−2.45x+34.11, r=−0.309, P=0.3285 based on Pearson's correlation coefficient.

• 

  Fig. 3 PFGE profiles of SmaI-digested genomic DNA from isolates of Acinetobacter baumannii. The dashed line indicates 80% similarity. HA isolates are outlined, and the others are CO isolates. Numbers represent the date of specimen collection.Abbreviations: PFGE, pulsed-field gel electrophoresis; HA, healthcare-acquired; CO, community-onset.

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