Epidemiology of ciprofloxacin-resistant Pseudomonas aeruginosa in a veterans affairs hospital.

This study was performed to identify risk factors for the nosocomial acquisition of ciprofloxacin-resistant Pseudomonas aeruginosa (CRPA) in a Veterans Administration hospital between January 1994, and March 1995. The study was a retrospective comparison of host factors and in-hospital exposures of patients who acquired nosocomially CRPA and ciprofloxacin-sensitive P. aeruginosa (CSPA). Participants included 42 adult patients with nosocomial CRPA acquisition and 52 adult patients with nosocomial CSPA acquisition. Before pseudomonal acquisition, antecedent ciprofloxacin receipt (50% compared with 8%; odds ratio [OR], 12; p = 0.001), the presence of an indwelling airway (36% compared to 17%; OR, 2.6; p = 0.04), and documented antecedent infection (74% compared to 52%; OR, 2.6; p = 0.03) were significantly associated with acquisition of CRPA. On multivariate analysis, antecedent ciprofloxacin receipt (OR, 16.8; p = 0.0001) and presence of an indwelling airway (OR, 10.5; p = 0.009) remain as significant associations. Furthermore, the test of significance confirmed synergy between these two factors. Antecedent ciprofloxacin therapy and indwelling airway act independently and synergistically to promote CRPA acquisition.

An evaluation of the Kemtek 1000 sample processor.

The Kemtek 1000 Sample Processor has been evaluated for precision, accuracy, speed and reliability. Precision was better than 1.0% at all volumes tested and accuracy within +/-5%. A l00-tube assay could be set up within 15 min when patient specimens plus two reagents were sampled using a two probe system. Carry-over could be reduced to <0.01% by using a sufficient number of wash steps, the latter being related to the assay requirements. Evidence was found for adsorption of protein to the probe tubing but inaccuracies due to this could be reduced by introducing wash steps between samples. Problems over 12 months have been minor and quickly resolved. The authors were pleased with the way the processor performed and their staffhave confidence in leaving it to set up their assays.

Survey of multiply resistant Providencia stuartii in a chronic care unit.

Providencia stuartii was cultured over a 4-year period from the urinary tract, throat, perineum, axilla and stools of patients in a long-term chronic care unit, the most common site of colonization being the urinary tract. A total of 17 patients had Prov. stuartii bacteraemia and manipulation of the urinary tract preceded bacteraemia in 10 cases. Eighty-two per cent of the patients had long-term urinary tract colonization from 1 month to 4 years. Although most isolates were resistant to all aminoglycosides except amikacin, the organisms were all susceptible to thienamycin, ceftazidime, cefotaxime, ceftizoxime and moxalactam.