The differentiation of coliform organisms infecting the urinary tract

The differentiation of Enterobacteriaceae infecting the urinary tract: A study in male paraplegics

Methods adopted in a routine bacteriology laboratory for the rapid identification of Enterobacteriaceae isolated from urine are described. The incidence of various bacteria causing infection in paraplegics after catheterization of the bladder is recorded, Klebsiella accounting for the majority of infections caused by lactose fermenters and Providence for the majority of ;paracolon' infections. The importance of these bacteria in cross-infection is discussed.

The diagnosis, epidemiology and control of urinary infection in urology and gynaecology

In a study of the urine after urological operations, quantitative bacteriological criteria for the diagnosis of infection were determined. The bacteria responsible for urinary infection after urological or gynaecological procedures sometimes came from the same patient, but more often came from other patients by cross-infection. The principal final route of entry was the urethra or the indwelling catheter lying in it. These findings led to the elaboration of methods of destroying bacteria in the urethra before operation, improving the disinfection of cystoscopes, and preventing the entry of bacteria via the indwelling catheter. Application of these methods reduced the incidence of infection after prostatectomy from 83% to 6%, and after emergency bladder drainage for acute retention of urine from 73% to 10%. A smaller improvement followed the introduction of closed bladder drainage after gynaecological operations.

IDENTIFICATION AND CLINICAL SIGNIFICANCE OF KLEBSIELLA SPECIES IN CHEST INFECTIONS

Using a short series of biochemical tests already in use in many routine laboratories, it is possible to identify strains of the genus Klebsiella and to differentiate K. aerogenes from other types. Marked production of slime is not peculiar to the group and colonial appearance alone is not a satisfactory basis for identification. K. aerogenes is the type most commonly isolated from all clinical specimens. It is suggested that the name may be retained in clinical bacteriology and used when applicable, particularly when reporting urinary strains. K. aerogenes is of doubtful pathogenicity when isolated from sputum; frequently its appearance follows antibiotic treatment for other organisms. It should be clearly distinguished from other Klebsiella types occurring as primary pathogens in sputum. Friedlander's bacillus is considered a suitable collective term for the latter, namely K. edwardsii-edwardsii, K. pneumoniae, and K. edwardsii-atlantae. The clinical significance of K. rhinoscleromatis and K. ozaenae could not be assessed as so few isolations were made. On the rare occasions when they occur they would, with the tests recommended, be included as Friedlander's bacillus, the distinction not being readily made in the clinical laboratory.

BACTERIOLOGICAL COMPLICATIONS FROM THE USE OF URETHRAL INSTRUMENTS: PRINCIPLES OF PREVENTION

Guidance by bacteriologists and changes in theatre and ward disciplines have greatly improved the results of urological surgery in recent years. The most noteworthy successes have been in treatment of chronic retention with renal failure, and in prevention of the bacteraemia which may occur following removal of the post-operative catheter or the passage of an instrument to dilate a stricture. It is hoped that safer urethral instrumentation may also reduce the incidence of chronic pyelonephritis.

Gram-negative bacilli in burns

In a period of two years, 865 strains of Gram-negative bacilli other than Pseudomonas aeruginosa isolated from burns were identified by a range of tests. The commonest species were Proteus mirabilis, Escherichia coli, and Enterobacter cloacae. Many strains of Klebsiella aerogenes, Enterobacter aerogenes, and Bacterium anitratum were also found.A large proportion of the strains were tested for sensitivity to nalidixic acid, ampicillin, kanamycin, chloramphenicol, tetracycline, and carbenicillin, and smaller numbers of strains were tested for sensitivity to cephaloridine, polymyxin, streptomycin, sulphadiazine, sulfamylon, and trimethoprim. The proportion of strains sensitive and resistant to different antibacterial agents varied widely with species of bacteria. A large proportion of the strains of E. coli and P. mirabilis were resistant to ampicillin, which was much used in treatment; resistance appeared least often towards nalidixic acid, kanamycin, trimethoprim, and gentamicin. Multiple resistance occurred less often among strains of E. coli than among Klebsiella spp, Enterobacter spp, and P. mirabilis. Phage and serological typing of Ps. aeruginosa showed that most infections of burns with this organism were due to strains previously found in other patients in the same ward. Taken with other evidence, this supported the view that most infections with Ps. aeruginosa were not acquired from the patient's own flora but from sources in the hospital environment.