Objective:

To describe the risk factors for colonisation or infection by carbapenem-resistant Acinetobacter baumannii in adults hospitalised in the ICU of 13 hospitals of Bogota.

Materials and methods:

A prospective, case control study. The case group was defined as having infection with carbapenem-resistant A. baumannii and the control group was defined as having infection with carbapenem-sensitive A. baumannii. We included 165 patients, one isolate per patient. Sensitivity was assessed in carbapenem-resistant A. baumannii and carbapenemase detection by PCR and pulsed field gel electrophoresis was performed on all patients.

Results:

Thirty isolates were carbapenem-sensitive A. baumannii and 135 were carbapenem-resistant A. baumannii (83.7% were multiresistant and 99% were sensitive to polymyxin). All isolates were positive to OXA-51. Of the carbapenem-resistant A .baumannii, 129 were positive to OXA 23, one to OXA-72 and the rest were positive to OXA-51. Using PFGE, 46 genotypes were identified, and the most common was Ab22 (n = 89). A total of 117 isolates were classified as infection and 48 as colonisation. Multivariate analysis determined the risk factors for carbapenem resistant A. baumannii to be: Previous hospitalisation (OR 11.9, 95% CI: 1.59 to 89), exposure to carbapenems for more than 3 days (OR 10.36, 95% CI: 1.73 to 61.95) and the presence of infection or colonisation by the Ab22 genotype (OR 449, 95% CI: 25 to 798).

Discussion:

A. baumannii is difficult to treat and eradicate from the hospital environment. This study identified 3 risk factors, 2 potentially associated with cross-infection (previous hospitalisation and the presence of a predominant clone) and the third was related to the use of carbapenems for more than 3 days.

Conclusion:

This study identified 3 risk factors, 2 potentially associated to cross-infection (previous hospitalisation and the presence of a predominant clone) and the third was related to the use of carbapenems for more than 3 days.

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