A controlled trial of the use of dip slides in general practice for the diagnosis of urinary infection.

A controlled trial of the use and interpretation of dip-inoculation slides for the diagnosis of urinary infection in four general practices is reported. Two slides were inoculated from each specimen, one being incubated and read in the surgery by the practitioner, the other being sent to the laboratory for incubation and interpretation. It is shown that the presence or absence of bacteriuria can be detected with a high degree of accuracy by a surgery procedure. The implications for the laboratory, the patient, and the practitioner are discussed. It is suggested that the financial saving on laboratory time and unnecessary treatment would far outweigh the outlay on apparatus and materials, and that many patients would benefit from the accurate diagnosis of urinary infection which, for a variety of reasons, is at present denied them.

Staphylococci as urinary pathogens.

During the course of one year all (382) strains of staphylococci isolated in significant culture from urine specimens were typed by the Baird-Parker method. Staphylococcus aureus accounted for only 63 (16%) of the infections. Novobiocin-resistant micrococcal infection occurred predominantly in young women but also in children of both sexes; it was not restricted to M3. To try to detect possible sources of micrococcal infection other than faeces the normal flora of the throat, urinary tract, and vagina of young women was studied. Novobiocin-resistant micrococci were rarely found. Previous reports that micrococci are the second commonest urinary pathogens in young women in domiciliary practice were confirmed. The laboratory records of patients with these infections suggested that they respond well to treatment and that recurrences are usually due to a different organism.

Human infections with thymine-requiring bacteria.

Clinical details are presented of 16 patients from whom thymine-requiring (thy-) mutants of pathogenic organisms were isolated; all had been treated with co-trimoxazole. The urine of six patients infected with thy- mutants contained levels of a thymine-like compound sufficient to support their growth. This might be the result either of the breakdown of pus cells or of thymine production by living bacteria that persist in stones or scar tissue, a suggestion supported by the observation of mutant growth "in satellitism" in vitro. Since 1975 we have isolated mutants from patients who have had short courses of co-trimoxazole, in contrast to those we reported upon previously, all except one of whom had had long courses. We are now isolating thy- mutants more frequently than hitherto. Secondary mutations to a low thymine requirement may now be occurring more rapidly, thereby allowing more mutant organisms to survive. The clinical significance of infection with thy- mutants is not yet clear, but evidence is accumulating that they are pathogenic. Alternative chemotherapy is suggested for patients from whom such mutants have been isolated.

A new look at the diagnosis of infection of the urinary tract and its adjacent structures.

The criterion enunciated by Kass for interpreting the quantitative examination of urine is critically reappraised. The role of organisms other than those of the aerobic bowel flora, especially fastidious organisms, in urinary tract infections is discussed in detail. Clinical microbiologists are urged to pay more attention to the bacteriological examination of urine and to play a greater part in the diagnosis and treatment of infections of the urinary tract and its adjacent structures.

Study of urinary tract infection in children in one health district.

OBJECTIVES: To determine the number of children who had urine specimens sent for culture, who had infections or sterile pyuria, and who were investigated further. To relate the laboratory findings to the results of imaging. DESIGN: One year survey of urine specimens submitted to a laboratory; review of previous and subsequent laboratory reports; review of the findings of imaging of the urinary tract. SETTING: Portsmouth and South East Hampshire health district. SUBJECTS: An estimated population of 89,086 children aged 12 years or under. MAIN OUTCOME MEASURES: Urine bacterial count and results of imaging. RESULTS: 12,551 urine specimens were submitted from 7450 children, 3138 boys and 4312 girls. 2238 children had infection or sterile pyuria at least once during the study (13.9/1000 boys, 37/1000 girls). 996 (45%) of the children with infection or sterile pyuria underwent some form of imaging. 128 children who had infection or sterile pyuria were already known to have urinary tract abnormalities and 114 children had newly identified abnormalities (1.0/1000 boys, 1.5/1000 girls). 50 (44%) of the children with newly detected abnormalities had no pyuria and 48 (42%) had bacterial counts below 10(8)/l. Eight children who had sterile pyuria on presentation were found to have abnormalities on imaging. CONCLUSIONS: Urinary tract infection is much commoner in children than is widely believed. Low bacterial counts, the absence of pyuria, or a finding of sterile pyuria should not be disregarded.

Suprapubic aspiration under ultrasound guidance in children with fever of undiagnosed cause.

OBJECTIVES: To assess the ease of use of suprapubic aspiration of urine under ultrasound guidance in babies with fever of uncertain cause and to assess the importance of bacterial counts and pyuria in relation to abnormalities of the urinary tract and the importance of pyuria in the absence of bacteriuria. DESIGN: Analysis of urine samples obtained by suprapubic aspiration in babies and children from July 1991 to June 1992. The clinical records of the children with bacteriuria and sterile pyuria were examined retrospectively. SETTING: Neonatal and paediatric wards of a district general hospital. SUBJECTS: 508 babies and children who had fever of uncertain cause or were seriously ill. RESULTS: No difficulties arose in the collection of 545 specimens. Bacteria were isolated from the specimens of 44 children, 24 of whom had abnormalities of the urinary tract. The bacterial count was < 10(8)/l in 18 of the children with bacteriuria, 10 of whom had abnormalities. No white cells were seen in 22 of the 46 bacteriuric specimens; nine of the children with no pyuria had vesicoureteric reflux. 439 of the 499 non-bacteriuric specimens showed no white cells. 60 children had pyuria without bacteriuria. CONCLUSIONS: The use of ultrasound guidance simplifies suprapubic aspiration of urine in babies. Low bacterial counts may be associated with abnormalities of the urinary tract. Laboratory techniques capable of detecting such counts reliably should be used. Pyuria is absent in half of babies and very young children with bacteriuria. It rarely occurs without bacteriuria, and if it does an explanation should be sought.

The natural history of urinary tract infection in women.

Many women who suffer from the symptoms of urinary tract infection have a negative urine culture when conventional methods are used. Their condition is described as 'urethral' (or 'dysuria/frequency') syndrome' (US). As they may be indistinguishable clinically from those with positive cultures antibiotics are often prescribed. Their symptoms are usually recurrent and they may receive many courses of treatment. Some women are said to have 'interstitial cystitis' (IC); they have a long history of symptoms and antibacterial treatment. The urine contains white blood cells (pyuria) and biopsy of the bladder wall shows the histological changes of chronic inflammation. Additional culture techniques applied to urine from these two groups of patients consistently yield bacteria, most commonly lactobacilli in those with US. From the urine of women with IC, lactobacilli and some other 'fastidious' bacteria are isolated from catheter specimens and also from bladder wall biopsies. These bacteria are known to be constituents of the mixed commensal flora of the distal one-third of the urethra. It is proposed that these two syndromes are different stages in the natural history of UTI, and that antibacterial agents, by selection of resistant bacteria in the urethral commensal flora, are an important aetiological factor. It is possible that these bacteria may invade the paraurethral glands via their ducts - a situation analogous to invasion of the prostate in men. There is a considerable body of evidence supporting this hypothesis, but as it all emanates from one centre it needs to be confirmed elsewhere. Acceptance would bring great clinical benefit and considerable financial savings. A laboratory protocol which requires only small additional expenditure, and a clinical management regimen are proposed. At present, much antibacterial treatment is prescribed and many patients undergo radiological and invasive investigations such as cystoscopy and urethral dilatation, the latter incurring the risk of post-instrumentation UTI. There is evidence that 'US' responds gradually if antibiotics are withheld. 'IC' is a more difficult problem because bacteria may have invaded the bladder wall. Carefully targeted antibacterial treatment given for at least 10-14 days might be effective, but there are no data on this. Rational management of 'US' might prevent the development of 'IC'. A recent thorough review of published work on this condition states that the aetiology is still unknown. It appears, however, that no attempt has been made in any recent studies to use urine culture techniques capable of detecting bacteria other than the recognised aerobic pathogens.