Ambient Air Contamination with Acinetobacter baumannii: Longitudinal observations based on the anatomic source of colonization
Previously we showed air contamination with Acinetobacter baumannii (AB) in a single ICU in 3 separate days. Now we aimed to determine the persistence of air contamination in the rooms occupied by AB(+) patients (pts) while comparing them to the air contamination of their immediate neighboring rooms. We also evaluated the impact of the anatomic source of colonization (e.g. rectum, respiratory) on the degree of air contamination.
This project was done between March-July 2013 in a large teaching hospital in Miami, FL across 7 adult ICUs. As standard practice, these ICUs perform active surveillance cultures on admission and weekly thereafter (rectum and -if intubated- respiratory tract). Once a new AB(+) pt was identified, daily ambient air surveillances were performed for 10 consecutive days. Open blood agar plates (2-ft from roof) were exchanged daily for the duration of surveillances. Control plates were obtained from adjacent rooms belonging to AB(-) pts. Plates were streaked using a sterile Q-tip, incubated overnight in TSB and plated on MacConkey. AB was determined based on colony color, morphology, and final identification by Vitek II. Air and pts isolates were typed using rep-PCR when available.
During 5-months, 30 AB (+) pts were identified: 17 respiratory (57%), 5 rectal (17%), and 8 (27%) from other sources. A total of 153 air-day samples were obtained. Pts colonized in the rectum had a mean proportion of days with AB in the air of 0.26 compared to 0.11 and 0.14 among respiratory and other sources, respectively (Figure). Thirty adjacent rooms occupied by AB(-) pts were cultured concomitantly (153 air-day samples). The proportion of days that these neighboring rooms were observed as having AB in the air was 0.11 (p=0.036)
There were six cases where both patient and air isolates were available, four of the matching isolates shared >95% similarity between each other, whereas none of the air isolates from the adjacent rooms were closely related with the patient isolates.
Aerosolization of AB seems to be present throughout consecutive days among AB(+) pts and this aerosolization appears to be higher among rectally colonized patients.
R. Viau, None
R. Bonomo, None
T. Cleary, None
N. Namias, None
D. H. Kett, None
Y. Doi, None
L. S. Munoz-Price, None
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