Molecular differentiation of multidrug-resistant Acinetobacter baumannii clinical strains in a Greek hospital

Abstract number: 1733_839

Papa A., Koulourida V., Moskophidis M., Antoniadis A.

Objectives:Acinetobacter baumannii is an important cause of nosocomial infections especially among critical ill patients. The number of multidrug-resistant (MDR) strains of A. baumannii is increasing, resulting in great problems for choosing the proper treatment. Aim of the present study was the molecular typing of MDR A. baumannii strains isolated during the last year in a tertiary Greek hospital.

Material and Methods: Thirty-five non-replicated multiresistant A. baumannii strains isolated from patients from various wards of Papageorgiou General Hospital were tested: 14 patients were hospitalised in the ICU, 11 in the internal medicine wards and 10 in the surgery wards. Susceptibility to 20 antibiotics was tested by microdilution method. RAPD and PFGE using ApaI were used for molecular typing of the strains. In addition, PCR was applied for the detection of integrase genes int1, int2 and int3.

Results: The 35 strains were divided into three clonal groups using RAPD and PFGE. The two methods gave similar results. The first group consisted of 18 strains, the second group of 12 strains, while the third one of 5 strains. Strains of the first two groups were dispersed in all wards, while the majority (80%) of the strains of the third group was isolated from the internal medicine ward. All strains presented similar multi-resistant patterns, with the exception of the third group which was susceptible to aminoglycosides. Class 1 integrons were missing from the strains of the third group, while it was present in all other strains. Class 2 or 3 integrons were not detected.

Conclusions: Three different clonal groups of A. baumannii strains are present in the hospital during the last year. The main difference among them is the resistance to aminoglycosides combined with the presence of intI gene in strains of two of the three groups. Results of this study gave an insight into the molecular diversity of multiresistant A. baumannii strains isolated in Papageorgiou hospital during the last year.