To ascertain the presence of air contamination with carbapenem-resistant Acinetobacter baumannii (CRAB) in an endemic hospital in Thailand.
From 1/4/15-1/25/15, twice weekly air sampling was performed to evaluate the presence of air contamination with CRAB in 4 units. Units selected were 2 open medical care units that harbor close-circuit ventilated CRAB patients (experimental units) and 2 open OB/GYN units (control units) that did not harbor CRAB patients. Twice a week air sampling was performed using standard technique of settle plate method. Two settle plates were placed in the vicinity at the bedside of each ventilated patient with CRAB in experimental units and 2 settle plates were placed in the vicinity-at the bedside of each patient in control units. Data was prospective collected that included patient characteristics, rates of A .baumannii infection in each of the unit, proportion of ventilated patients, patient-days and colony forming units of bacteria per cubic square meter of each patient.
In the experimental unit, ventilated patients consisted of 39% (69/180) of patient population and 64% (1049/1640) of patient-days while there was no ventilated patient in the control units. The median density of CRAB were 7.1 cases/1000 vs. 0 cases/1000 patient-days in experimental vs. control units (P<0.001) respectively. There were 856 patient areas cultured (434 in experimental units and 422 in control units). The median number of bacterial air sampling were 781 vs. 514 CFU/mm3 (experimental units vs. control units; P<0.01) respectively. Multiple microorganisms were isolated from the air sampling, however, the patterns were different from experimental vs. control units: Corynebacterium spp. (240 vs. 860CFU/mm3; P = 0.02), Staphylococcus coagulase negative(440 vs. 660CFU/mm3; P = 0.04), Micrococcus spp.(440 vs. 860CFU/mm3; P = 0.01), Proteus mirabilis (651 vs. 106CFU/mm3; P = 0.001), non-fermentative Gram-negative rods (not Pseudomonas spp and Acinetobacter spp.; 151 vs. 54CFU/mm3; P = 0.001). CRAB did not grow in any of the plates.
In open inpatient unit where ventilated patients with CRAB were hospitalized, there was no evidence of aerosolization. Airborne isolation is not indicated in ventilated patients with CRAB.
P. Laovachirasuwan, None
N. Singh, None