[Management of an Outbreak with Cases of Nosocomial Pneumonia Caused by a Novel Multi-Drug-Resistant Acinetobacter baumannii Clone].

We describe the detection and investigation of an outbreak involving a multi-drug-resistant acinetobacter (A.) baumannii clone in the neurological intensive care unit (ICU) at the University hospital Rostock (Germany). The bacteria were isolated from 7 ICU patients within 20 weeks, six of them showing signs of pneumonia. Among 24 tested antibiotics, the isolates were only susceptible to colistin. An epidemiological investigation revealed the presence of multi-drug-resistant A. BAUMANNII isolates in 13 of 37 samples from medical devices, patient-associated objects and room equipment from the patients' environment. When investigating the source of this strain in our hospital, we found that it first appeared three years before. Since then it has caused sporadic infections in the medical and neurological ICUs prior to the presented outbreak. The identity of all isolated strains with the novel clone was demonstrated with pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). A multimodal intervention program was introduced by the hygiene staff on the affected ICU. It included consequent enforcement of standard hygiene precautions, repeated staff education and elaborated disinfection protocols specifically addressing the patients' environment. The procedures led to cessation of A. baumannii detection in environmental samples. Thereafter, the outbreak was cleared within 20 weeks.