A simple test for significant bacteriuria

METHOD FOR THE DETECTION OF SIGNIFICANT BACTERIURIA IN LARGE GROUPS OF PATIENTS

A measured area of blotting paper was used as a vehicle for transferring a constant aliquot of urine on to the surface of a culture medium. The number of bacterial colonies growing in the inoculum area of the medium corresponded to the number of organisms in the urine. One thousand, two hundred and seventy-five urines from women attending an ante-natal clinic were tested by this method, and the results compared with the results of quantitative bacterial counting and of triphenyl tetrazolium chloride (T.T.C.) tests. The method was found to be a simple, cheap, and reliable way of screening urine specimens for significant bacteriuria.

Criteria for diagnosis of urinary tract infection and evaluation of therapy

Patients with urinary tract infections are commonly used to study the efficacy of new antibiotics. Some criteria, for example the presence of more than 100,000 organisms of a single species per ml as an indicator of infections, have been accepted for many years but all rules have exceptions. Other criteria such as relapse, re-infection are less clearly agreed. Furthermore, timing of collection of specimens during and after treatment shows great variation in protocols and in definition. These criteria and the methodology of collecting, transportation and examination of urine are discussed.

Triphenyl tetrazolium chloride (TTC) dye test for quick diagnosis of urinary tract infection

We evaluate the triphenyl tetrazolium chloride (TTC) dye reduction test for quicker diagnosis of urinary tract infections for its sensitivity and reliability to detect significant bacteriuria. Of the 1400 urine samples tested 780 (55.7%) had significant bacteriuria. TTC dye test was positive in 678 (86.9%) of those with significant bacteriuria thereby showing its usefulness. The test is simple and cheap and can be carried out in field situations.

Gas-chromatographic detection of urinary tract infections caused by Escherichia coli and Klebsiella sp

A gas-chromatographic method for the diagnosis of urinary tract infections caused by Escherichia coli and Klebsiella sp. is described. A total of 96 urine samples from individuals with clinical symptoms of urinary tract infection or pyrexia of unknown origin were tested by conventional and gas-chromatographic methods for bacteriuria. The gas-chromatographic method showed complete agreement with the conventional method in diagnosing all of 16 cases of bacteriuria caused by E. coli and 4 cases caused by Klebsiella sp. The remaining two cases of bacteriuria, caused by other bacteria, were not detected by the gas-chromatographic method.

Evaluation of the MS-2 urine screening method for detection of bacteriuria

A collaborative evaluation of the MS-2 urine screening system indicated that the automated method could successfully identify at least 84% of urine specimens that contained greater than or equal to 10(5) colony-forming units per ml. Most specimens not detected as positive by the system contained primarily diphtheroids and yeasts. Excluding those specimens which contained diphtheroids and yeasts, the MS-2 system correctly identified as positive 94.8% of specimens that contained greater than or equal to 10(5) colony-forming units per ml and as negative 96.1% of specimens that contained less than 10(4) colony-forming units per ml. The automated system is an attractive method for the screening of urine specimens for significant bacteriuria.

Evaluation of Gram-stain screen and Micro-ID methods for direct identification of Enterobacteriaceae from urines

A rapid method of urine screening and enterobacterial identification was evaluated. Results indicated that an average of 13.5 bacteria/oil immersion field (threshold value greater than or equal to 1) was observed in unsedimented urine of patients with significant bacteriuria, with an average of less than 1 bacterium/field in urines of patients without significant bacteriuria. In centrifuged urines, numbers of bacteria divided by amount of urine sedimented yielded similar results. Of 1758 urines studied, 136 yielded greater than or equal to 10(5) bacteria/ml, and 58 greater than 10(4) but less than 10(5) bacteria/ml, by conventional techniques. Gram-screening of unsedimented specimens gave sensitivity rates of 94.1%, specificity of 97.7%, and predictive positive and negative values of 78.5%, 99.5%, respectively; similar values were obtained with sedimented urines. Sensitivity rates of both screening methods for the 58 urines with greater than 10(4) but less than 10(5) bacteria/ml were 9.0%, 10.0%, respectively. Total correct enteric identification in 113 urines with positive screens and significant bacteriuria (greater than or equal to 10(5)/ml) was 82.3% and 90.3% with direct saline and broth Micro-ID methods, respectively. In 99 urines yielding pure or predominantly pure growth of 1 species of Enterobacteriaceae identification by direct saline and broth Micro-ID corresponded with isolated colony identification in 85.9%, 94.9% of cases, respectively. Gram-stain screening (together with back-up conventional plating in certain patient categories) and enterobacterial identification by direct broth Micro-ID, of urines with pure stains suggestive of greater than or equal to 10(5) Gram-negative rods/ml has been shown to be useful in laboratories without automated equipment for urine screening.

Automated direct antimicrobial susceptibility testing of microscopically screened urine cultures

Two screening methods for urine microbiology are proposed: one in which the Gram-stained smear is used to detect significant bacteriuria, and another in which Autobac antibiotic susceptibility tests are performed directly on positive urine samples. Results on 1,350 specimens indicated that an average of 18 bacteria per oil immersion field were observed in the urine of patients with significant bacteriuria, and an average of less than 1 bacterium per oil immersion field was found in the urine of patients without significant bacteriuria. Direct susceptibility testing by Autobac proved to be rapid (3 h versus 24 h) and reliable (0.5 to 1.2% discrepancies).

Rapid screening for significant bacteriuria using a Coulter Counter

A Coulter Counter was evaluated for detecting significant bacteriuria. Simple urinary particle counts showed agreement in 883 of the 956 (92.4%) urine specimens examined compared to a standard culture procedure. They also provided a semiquantitative estimate of bacterial numbers in specimens diagnosed as infected by culture. Sample preparation before counting was minimal, and results were obtained within two to four minutes.

Clinical trial of a chemical test for bacteriuria

A chemical test for the detection of bacteriuria-Uriglox-has been compared with the results obtained on culturing urine obtained by suprapubic aspiration in 351 pregnant or puerperal women. The results of this comparison show a correlation of 96.9%, both false positive and false negative results occurring.

Bacteriuria in a Scottish island community. A comparison of chemical and cultural tests for bacteriuria applied in remote surroundings

Four hundred and thirty-eight overtly healthy adults on Tiree were screened for bacteriuria by dip-inoculum culture and a tetrazolium reductase test.Dip-inoculum culture affords a simple and effective means of providing a service in quantitative urine bacteriology for communities remote from a laboratory.The pattern of bacteriuria on Tiree is much the same as in other communities surveyed. Criteria are discussed for assessing the sensitivity of the tetrazolium test in terms of quantitative urine culture.

Method for detection of bacteriuria suitable for use in general practice

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Use of a solid reagent in the triphenyl tetrazolium chloride test for bacteriuria

The use of a solid reagent in the triphenyl tetrazolium chloride (T.T.C.) test for significant bacteriuria is described. The reagent gave a positive result with 108 (86%) of 126 specimens of urine containing over 100,000 organisms per ml. In comparison with the standard T.T.C. test the modified test gave comparable results. Some possible reasons for the varying results obtained by different users of the T.T.C. test are discussed.