Some observations on urinary tract infections in patients undergoing long-term bladder catheterization

In this study five laboratory media have been used to characterize the bacterial flora of urine from patients with spinal injuries who are undergoing long-term indwelling bladder catheterization. Single organisms were rarely isolated from these urines, in general complex mixed communities of bacteria were recovered composed of up to seven species. Observations were also made on how these populations change with time and in response to antibiotic therapy and bladder irrigation with antiseptics. During periods when patients were not receiving antibacterials, Escherichia coli, Klebsiella pneumoniae, Citrobacter diversus, Providencia stuartii, Pseudomonas aeruginosa, Proteus mirabilis and Pr. morganii were stable inhabitants of the urine, Streptococcus faecalis, Acinetobacter anitratus and Staphylococcus epidermidis were transient members of the communities. The effect of antibacterials on these communities was merely to select species that were resistant to the agents used. These results suggest that if these patients are to be treated, then efforts should be made to fully characterize the bacterial populations of the urines. Any therapy should then be based upon a consideration of the resistance profiles of all the members of the mixed bacterial flora.