Environmental contamination with an epidemic strain of Pseudomonas aeruginosa in a Liverpool cystic fibrosis centre, and study of its survival on dry surfaces.

We conducted an environmental survey in the Liverpool adult cystic fibrosis (CF) centre in order to determine the extent of environmental contamination with an epidemic strain of Pseudomonas aeruginosa that colonizes most CF patients in Liverpool, and to identify possible reservoirs and routes of cross-infection. In addition, we studied the survival of this strain on dry surfaces, compared with that of other CF P. aeruginosa strains, to explore factors that might contribute to its high transmissibility. Samples were collected from staff, patients and the environment (drains, bath tubs, showers, dry surfaces, respiratory equipment and air) in the inpatient ward and outpatient clinic. P. aeruginosa strains were tested using a new polymerase chain reaction amplification assay specific for the Liverpool epidemic strain (LES). LES was isolated from patients' hands, clothes and bed linen. Environmental contamination with LES was only detected in close proximity to colonized patients (external surfaces of their respiratory equipment, and spirometry machine tubing and chair) and was short-lived. No persistent environmental reservoirs were found. LES was detected in the majority of air samples from inside patients' rooms, the ward corridor and the outpatient clinic. Survival of LES on dry surfaces was significantly longer than that for some other strains tested, but not compared with other strains shown not to be transmissible. Improved environmental survival on its own, therefore, cannot explain the high transmissibility of this epidemic strain. Our study suggests that airborne dissemination plays a significant role in patient-to-patient spread of LES, and confirms the need to segregate those patients colonized by epidemic P. aeruginosa strains from all other CF patients.

A case of lower respiratory tract infection caused by Neisseria weaveri and review of the literature.

Neisseria weaveri (formerly CDC [Centers for Disease Control and Prevention] group M-5 is part of the normal canine oral flora. Infections in humans are usually associated with dog bite wounds. Very rarely the organism has been isolated from sites other than wounds, or from deep seated infections. A 60-year-old man was admitted to our hospital because of an acute exacerbation of his bronchiectasis. Gram stain of bronchial washings and expectorated sputum showed numerous polymorphs and Gram-negative bacilli. Routine bacterial culture yielded a heavy pure growth of a Gram-negative rod-shaped organism that was strongly oxidase and catalase positive, indole negative, non-motile and did not ferment carbohydrates. The organism was identified as N. weaveri by using 16S rRNA sequencing. The patient was treated with a 3 weeks course of ofloxacin and had a good response. Sputum culture after treatment yielded normal respiratory flora only. To our knowledge, this is the first reported case of lower respiratory tract infection caused by N. weaveri.

Intracerebral sepsis due to intestinal perforation by ventriculo-peritoneal shunts: two cases.

Two cases of ventriculo-peritoneal (V-P) shunt infection attributable to intestinal perforation are reported. One patient developed a brain abscess, the other ventriculitis. Microbiology consisted of faecal flora and the peritoneal catheter was found to be faecally stained in both cases. There were no abdominal symptoms or signs. It is likely that infection developed via the ascending route.

Heat tolerance of vancomycin resistant Enterococcus faecium.

The heat tolerance of 27 Enterococcus faecium isolates in water was studied. Stationary phase cultures including vancomycin resistant and sensitive clinical and food isolates were exposed to heat at 60 degrees, 65 degrees, 71 degrees, and 80 degrees C for one, three, 10, and 30 minutes and the log10 reductions in bacterial counts were determined. Exposure at 71 degrees and 80 degrees C resulted in > 6 log10 reduction in viable counts for all isolates. Seven (24%) isolates survived (< 5 log10 reduction) heat at 65 degrees C for 10 minutes. The E faecium isolates were more resistant to heat than the two E faecalis reference strains. No differences in heat tolerance were observed between vancomycin sensitive and resistant strains or between isolates of human or food origin.