Tracing of pseudamonas aeruginosa infection by the use of commercial antisera and pyocin production and the evaluation of the results on the basis of the chi2 test.

Abstract

One hundred randomly collected Psuedomonas aeruginosa isolates were examined during a two months period of time in order to determine their origin in a hospital environment. Initially, neither the source of the isolates, nor the patients' names were known. The serogroups were determined with commercial antisera, and the pyocin patterns were established with the simplified method of mitomycin C induced pyocin production. The results were analysed in the chi2 test. A highly significant probability value (p less than 00004) was taken as evidence of the identity of the isolates, especially among strains originating from the neurosurgical, surgical and medical intensive care units investigated. The simplified method of the originally devised mitomycin C induced pyocin production with a selected number of 'indicator' strains in conjunction with the initial serogroup determination by the commercially available antisera, allowed a rapid tracing of all Pseudomonas aeruginosa isolates. This combined method is recommended as an easy and useful epidemiological tool for the study of Pseudomonas aeruginosa hospital acquired infections.