Acinetobacter - the trojan horse of infection control?

BACKGROUND: Five cases of multi-resistant Acinetobacter baumanii (MRA) producing OXA-23 and OXA-51 occurred in a regional burn intensive care unit (BICU). Three were repatriated from other parts of the world (Dubai and Mumbai) and colonized on admission. Despite optimal precautions, two patients acquired MRA. Both had been nursed in the same room. METHODS: Multi-disciplinary outbreak investigation of MRA in a regional BICU. FINDINGS: The mechanism of transfer for the first case is thought to have been contaminated air from theatre activity releasing MRA bacteria into the communal corridor. No MRA patients went to theatre between the first and second acquired cases. The mechanism of transfer for the second case is thought to have been via a shower unit that was decontaminated inadequately between patients. CONCLUSION: In an outbreak where contact precautions and environmental cleaning are optimal, it is important to give careful consideration to other mechanisms of spread. If there is a failure to do this, it is likely that the true causes of transmission will not be addressed and the problem will recur. It is recommended that burn theatres within burn facilities should be designed to operate at negative pressure; this is the opposite of normal operating theatre ventilation. Where showers are used, both the shower head and the hose should be changed after a patient with a resistant organism. The role of non-contact disinfection (e.g. hydrogen peroxide dispersal) should be reconsidered, and constant vigilance should be given to any 'trojan horse' item in the room.

Inheritance of nuclear DNA markers in gynogenetic haploid pink salmon.

We describe the inheritance of 460 PCR-based loci in the polyploid-derived pink salmon (Oncorhynchus gorbuscha) genome using gynogenetic haploid embryos. We detected a length polymorphism in a growth hormone gene (GH-2) intron that is caused by an 81 bp insertion homologous to the 3' end of the salmonid short interspersed repetitive element (SINE) SmaI. Such insertion polymorphisms within species bring into question the use of SINEs as phylogenetic markers. We confirmed that a microsatellite locus encodes a PCR-null allele that is responsible for an apparent deficit of heterozygotes in a population sample from Prince William Sound. Another set of microsatellite primers amplified alleles of the same molecular weight from both loci of a duplicated pair. In our analysis of several PCR-based multilocus techniques, we failed to detect evidence of comigrating fragments produced by duplicated loci. Segregation analysis of PCR-based markers using gynogenetic haploid embryos ensures that the interpretation of molecular variation is not complicated by heterozygosity, diploidy, or gene duplication. We urge investigators to test the inheritance of polymorphisms in salmonids prior to using them to measure genetic variation.