Acinetobacter species and strains in a university hospital during a four-year period

Abstract number: 1134_04_145

Dijkshoorn L., Bernards A.T., van der Reijden T., van den Broek P.H.

Objectives:  

Despite the numerous reports of outbreaks by acinetobacters, relatively little is known about the general incidence of Acinetobacter species in hospitals. The aim of the present study was to investigate the species and strain distribution of Acinetobacter during a four-years’ period in the Leiden University Medical Center using validated genotypic methods for species and strain identification.

Methods:  

Isolates were identified to species by the use of AFLP analysis and/or amplified ribosomal DNA analysis (ARDRA). AFLP was also used to identify isolates at the strain level using a grouping level of >=90% as a threshold above which organisms were considered to belong to the same strain.

Results:  

In total, the investigated number of isolates of the period of study were 37 out of 25 patients (1999), 79 out of 47 patients (2000), 126 out of 53 patients (2001) and 39 out of 25 patients (2002). Isolates were identified to 15 named and unnamed species with Acinetobacter baumannii (62 patients) and the unnamed genomic species 3 (39 patients) being the most prevalent. Isolates of 11 patients could not be identified to any of the described species of Acinetobacter. Cross-infection was noted for A. baumannii (4 strains, 35 patients), genomic species 3 (3 patients), yet unclassified strain (2 patients), and gen.sp. 10 (2 patients). In 1999–2000 one A. baumannii strain was epidemic in the hospital, affecting 29 patients. Exclusion of this epidemic strain from the study, revealed the more endemic level of occurrence of Acinetobacter species.

Conclusion:  

The current study provided insight in the prevalence of different Acinetobacter species in the hospital of study. Apart from A. baumannii, many other species can be found in clinical specimens, some of which may also spread among patients and may be of clinical significance.