title: Nosocomial colonization and infection with multiresistant Acinetobacter baumannii: outbreak delineation using DNA macrorestriction analysis and PCR-fingerprinting.
abstract: The prevalence of nosocomial acinetobacter colonization and infection in a university hospital was reviewed and multiresistant Acinetobacter baumannii infections in an intensive care unit (ICU) were investigated using epidemiological typing and a case-control study. Acinetobacter colonization at various body sites was found in 3.2 to 10.8 per 1000 patients. Acinetobacter infection accounted for 0.3% of endemic nosocomial infections in critically ill patients and for 1% of nosocomial bacteraemia hospitalwide. Over a three-week period, four ventilated patients developed colonization, followed by pneumonia in two patients, with A. baumannii resistant to multiple antimicrobials. Cultures of samples from respiratory equipment and ICU surfaces (n = 27) as well as from hands of personnel (n = 14) failed to yield A. baumannii, except for one sample of respiratory tubing. Antibiogram, biotype, chromosomal DNA macrorestriction profiles and polymerase chain reaction (PCR) mediated fingerprints of A. baumannii isolates (n = 31) indicated that this outbreak was caused by two strains, one of which later spread to another hospital where it caused a second outbreak. Both strains were clearly discriminated from control strains from cases of sporadic infection. Risk factors for cross-colonization that were identified by a case-control comparison were neurosurgery, mechanical ventilation and treatment with broad-spectrum antibiotics. Transmission was controlled by implementing contact isolation precautions and routine sterilization of ventilator tubing. Wider use of sensitive genotypic methods like DNA macrorestriction analysis and PCR-mediated fingerprinting for typing nosocomial pathogens should improve the detection of micro-epidemics amenable to early control.
authors.affiliation: Department of Microbiology, Hospital Epidemiology, Bruxelles, Belgium.
authors.forename: M J
authors.initials: MJ
authors.lastname: Struelens
authors.forename: E
authors.initials: E
authors.lastname: Carlier
authors.forename: N
authors.initials: N
authors.lastname: Maes
authors.forename: E
authors.initials: E
authors.lastname: Serruys
authors.forename: W G
authors.initials: WG
authors.lastname: Quint
authors.forename: A
authors.initials: A
authors.lastname: van Belkum
mesh_terms: D000150:Acinetobacter / Q000145:classification / Q000302:isolation & purification*; D000151:Acinetobacter Infections / Q000382:microbiology*; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D016022:Case-Control Studies; D003428:Cross Infection / Q000382:microbiology*; D016172:DNA Fingerprinting; D004262:DNA Restriction Enzymes; D004196:Disease Outbreaks; D004352:Drug Resistance, Microbial; D006801:Humans; D007362:Intensive Care Units; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction
chemical_list: D004262:DNA Restriction Enzymes