Longitudinal nosocomial outbreak of Pseudomonas fluorescens bloodstream infection of 2 years' duration in a coronary care unit.

BACKGROUND: Outbreaks of bloodstream infections (BSI) of nonfermenting bacteria are a critical issue and often associated with hospital environments. We experienced a long-lasting outbreak of Pseudomonas fluorescens BSI limited to a coronary care unit (CCU). METHODS: We conducted a retrospective epidemiologic investigation and a case-control study for Pseudomonas fluorescens BSI from April 2011-July 2014. Environmental sample culture was conducted to detect the specific environmental source of transmission. RESULTS: Hospital-wide microbiology data from the term identified 13 case patients with P fluorescens BSI and 32 control patients with BSI due to organisms other than P fluorescens in the CCU. The case-control study revealed that the case group had significantly higher odds of exposure to only cardiac output (CO) measurement with thermodilution method (odds ratio, 22.0; 95% confidence interval, 2.4-202.3). The organism was identified only from an ice bath used for CO measurement. The susceptibility patterns were identical among all strains derived from the cases and the environment. CONCLUSIONS: The nosocomial outbreak of P fluorescens BSI in our CCU over 2 years was associated with a contaminated ice bath used for CO measurement within the unit. Detection and elimination of the specific source was essential to stop the outbreak.

The GINS complex from Pyrococcus furiosus stimulates the MCM helicase activity.

Pyrococcus furiosus, a hyperthermophilic Archaea, has homologs of the eukaryotic MCM (mini-chromosome maintenance) helicase and GINS complex. The MCM and GINS proteins are both essential factors to initiate DNA replication in eukaryotic cells. Many biochemical characterizations of the replication-related proteins have been reported, but it has not been proved that the homologs of each protein are also essential for replication in archaeal cells. Here, we demonstrated that the P. furiosus GINS complex interacts with P. furiosus MCM. A chromatin immunoprecipitation assay revealed that the GINS complex is detected preferentially at the oriC region on Pyrococcus chromosomal DNA during the exponential growth phase but not in the stationary phase. Furthermore, the GINS complex stimulates both the ATPase and DNA helicase activities of MCM in vitro. These results strongly suggest that the archaeal GINS is involved in both the initiation and elongation processes of DNA replication in P. furiosus, as observed in eukaryotic cells.