Level Of Bacteriuria Research Articles

Urinalysis for Bacteriuria

To the Editor.— We enjoyed reading the article by Komaroff et al in the JulyArchives(138:1069-1073, 1978) and agree that the urinalysis, particularly the examination for bacteriuria, can be helpful in discriminating between a urinary tract infection and vaginitis. In their study, Kunin's criterion 1 was used, which considers the counting of one to ten bacteria in an unstained urine sediment in a high-power dry microscopic field as a positive result. With 10 5 /cc bacteria denoting an important level of bacteriuria, Kunin's method results in approximately 12% false-positives and about that many false-negatives. We favor checking for bacteriuria in an unspun urine specimen stained with methylene blue. This technique eliminates variabilities of urine centrifugation and affords better visualization of bacilli; the dye aids in distinguishing cocciform bacteria from urinary debris. 1 Approximately 1/30,000 cc is contained in one highpower field, so that seeing one bacterium per field correlates

Neonatal Bacteriuria — The Value of Bladder Puncture in Resolving Problems of Interpretation Arising from Voided Urine Specimens

Abbott, G. D. (1978).Aust. Paediatr, J., 14, 83–86. Neonatal Bacteriuria — The value of bladder puncture in resolving problems of interpretation arising from voided urine specimens. During a study of neonatal bacteriuria in 1460 infants born consecutively it was found that 76% had either sterile urine, or less than 10 106 organisms/1 (10,000 organisms/ml) in a single ‘clean catch’ specimen. To establish the level of bacteriuria in voided specimens which correlates with bacteriuria obtained by aspirating urine suprapubically, check bladder punctures were carried out. This was done in infants with varying levels of colony counts obtained from voided specimens. No bladder puncture specimens showed evidence of infection when the colony count on the voided urine culture was less than 10 106 organisms/1. When the colony count on the voided urine culture was between 10 and 100 106 organisms/1, 2.2% of bladder puncture urines showed evidence of infection. When the voided urine colony count exceeded 100 106 organisms/1, 11.1% of bladder punctures showed evidence of infection. There was no significant correlation between baoteriuria and pyuria or proteinuria. While repeated collection and culture of ‘clean catch’ urines may reduce the Ca fusion due to contaminated specimens, this approach can be time consuming. It is recommended that if the colony count on a carefully collected ‘clean catch’ specimen exceeds 10 106 organisms/1, or if the infant has symptoms suggestive of infection, bladder puncture should be performed.

Renal infection in the rat after reflux challenge with Pseudomonas aeruginosa

A rat-pseudomonad reflux model was employed to examine the effect of the size of inoculum on the emergence of renal infection. Widely varying degrees of renal disease observed in challenged animals indicated that a number of variables influenced the outcome of the host-parasite interaction. In this regard, animals in which there was a reduction of the colony counts below a threshold figure rarely gave evidence of renal infection when examined at autopsy on the eighth day following reflux. These results suggest that a threshold level of bacteriuria may also have to be exceeded if renal infection is to become established in patients with vesico-ureteric reflux.

A comparison of methods for collecting clean-catch urine specimens in a clinic population of obstetric patients

A descriptive study comparing the use of the gram-positive skin cleansers Zephiran and hexachlorophene to Prepodyne, a gram-negative cleanser, was performed upon 1,469 specimens from patients attending the prenatal clinic of a large university hospital. The period prevalence rate of symptomatic and asymptomatic bacteriuria in 1,350 patients was 11.5 per cent. Group teaching compared to individualized teaching of the patients to collect their own aliquots did not appear to have a measurable effect upon the levels of bacteriuria. Significant differences were found at p = 0.05 between all the serially sampled groups using the different cleansers. No significant differences was found between the two groups using only hexachlorophene when compared for differences between patient-collected and nurse-collected specimens; nevertheless, the patient-collected specimens had greater proportions of low bacterial counts than those collected by the nurses. This study indicates that carefully instructed patients in large clinic populations are more efficient than the nurses when they collect their own midstream specimens, using an adequate cleansing agent. An analysis of the rates disclosed that Zephiran cleansing had high contamination levels, whereas Predodyne significantly reduced contamination of the specimens. However, the possible reduction of the rate of 105 specimens to 9.1 per cent in the group using Prepodyne did not rule out the possibility of reduced specificity, and the hazard of false-negative results occurring with the use of gram-negative skin cleansers requires further study.