1246. Acinetobacter baumannii in the post-acute care setting: prevalence and resistance rates in patients, health care personnel and the environment.
Session: Poster Abstract Session: Healthcare Epidemiology: Non-acute Care Settings
Friday, October 5, 2018
Room: S Poster Hall

Acinetobacter baumannii is an important agent of healthcare-acquired infections, sporting high resistance to major antibiotics in acute care. Since Ac. baumannii is an opportunistic pathogen commonly found in the environment, we aimed to investigate: 1): its prevalence as colonizer on patients, environment, and healthcare personnel (HCP) in Nursing Facilities (NFs) with intermediate intensity of care but high antibiotic pressure, and 2): whether resistance rates in colonizing strains vary between patient, environmental, and HCP isolates.


We analyzed Ac. baumannii patient and HCP colonization and environmental contamination in six NFs in Michigan. Samples were collected from HCPs hands, and from multiple patient body sites and high-touch surfaces at admission, 14 days, and monthly up to six months. Ciprofloxacin, imipenem and ceftazidime resistance was tested according to CLSI guidelines.


651 patients were screened (average follow-up time was 29 days). Patient colonization with Ac. baumannii was found in 59/1620 (3.64%) of visits, and environmental contamination in 267/1620 visits (16.48%) (p<0.001). Interestingly, HCP showed at least as high or possibly higher colonization rates than patients (32/574) (5.25%)(p=0.06).

Resistance rates differed significantly between HCP, environmental, and patient isolates, ranging from 35 to 38% for patient isolates, 26 to 30% for environmental isolates, and only 8 to 17% for HCP isolates (Table).

Table. Resistance rates of Acinetobacter baumannii to ceftazidime, imipenem, ciprofloxacin vary based on the source of isolation (patient, environment, HCP hands).

Patient isolates

Environmental isolates

HCP hands isolates


Total isolates





Resistant to:

Imipenem (%)

31 (36%)

118 (26%) p=0.047*

3 (8%) p=0.002**

152 (26%)

Ciprofloxacin (%)

32 (38%)

128 (28%) p=0.08*

5 (14%) p=0.009**

165 (29%)

Ceftazidime (%)

30 (35%)

137 (30%) p=0.34*

6 (17%) p=0.040**

173 (30%)

* patient isolates vs environmental isolates.

** patient isolates vs HCP hands isolates.


In our NFs, Ac. baumannii is more likely to be found on HCPs than on patients. However, HCP isolates have much lower resistance rates. Environmental contamination is alarmingly common, with worrisome resistance rates even in post-acute care settings.

Marco Cassone, MD, PhD1, Ziwei Zhu, MPH1, Kristen Gibson, MPH1, Bonnie Lansing, LPN1, Jie Cao, MPH1 and Lona Mody, MD, MSc2, (1)Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, (2)Internal Medicine, University of Michigan and VA Ann Arbor Healthcare System, Ann Arbor, MI


M. Cassone, None

Z. Zhu, None

K. Gibson, None

B. Lansing, None

J. Cao, None

L. Mody, None

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