Plasmid DNA fingerprinting of Acinetobacter species other than Acinetobacter baumannii

During the last years Acinetobacter species have emerged as clinically significant pathogens. Most infections are nosocomially acquired and mainly due to Acinetobacter baumannii. Little is known about the epidemiology and clinical significance of unnamed Acinetobacter species 3 (the second most often encountered member of the genus Acinetobacter) and other Acinetobacter species such as A. johnsonii, A. junii, and A. lwoffii. Seventy-five clinical isolates of Acinetobacter species other than A. baumannii (Acinetobacter species 3, n = 37; A. johnsonii, n = 20; A. junii, n = 8; A. lwoffii, n = 10) recovered from 66 patients over a period of 12 months were analyzed by plasmid DNA fingerprinting. Plasmids were found in 84.4% of Acinetobacter species 3 isolates and in all A. johnsonii, A. junii, and A. lwoffii isolates. Strains harbored up to 15 plasmids each. Almost every isolate gave a unique plasmid pattern. With one exception, identical plasmid profiles were detected only in corresponding isolates recovered from blood cultures and intravascular catheters from a given patient. Plasmid DNA fingerprinting proved to be useful for typing Acinetobacter species other than A. baumannii. There was no evidence of patient-to-patient transmission or hospital outbreaks due to these species. This finding is in contrast to the results obtained in studies of the hospital epidemiology of A. baumannii.