A study of microscopical and chemical tests for the rapid diagnosis of urinary tract infections in general practice.

Aids to the rapid diagnosis of urinary tract infection were assessed by the examination of 325 consecutive urine samples taken in the normal course of work in a general practice. Of these samples 103 produced a pure growth of at least 10(5) organisms per ml. The appearance and smell of each sample was noted and it was then tested by simple low-power microscopy of a drop of urine and by a dipstick which measured leucocyte esterase and nitrite, together with protein, blood and pH. In addition, pus cell counts per mm3 were performed on 272 of the samples using a cytometer chamber. This method is too time-consuming for routine use in the surgery. Neither a cloudy appearance nor haematuria were sufficiently specific to be of much use in the diagnosis of urinary tract infection. In the prediction of a 'positive' culture the sensitivity and specificity of the other tests were as follows: drop method microscopy 95% and 76%, respectively; cytometer count 95% and 81%; leucocyte-esterase estimation 89% and 68%; and nitrite 57% and 96%. These figures may underestimate the true values of the tests in the diagnosis of urinary tract infection because infection may be present in some cases producing growths of less than 10(5) organisms per ml. It is concluded that the most useful aid to the diagnosis of urinary tract infection is low-power microscopy of a drop of urine.

The bacteriology of a rural general practice: a retrospective six-year study.

The organisms cultured and their antibiotic sensitivities, together with clinical details, were obtained from all the available bacteriology requestlresult forms from a rural practice over a six-year period. The 3022 bacteriology specimens analysed yielded 997 potential pathogens. The main infections studied were those of the urinary tract, the upper respiratory tract and the skin and soft tissue. In spite of the fact that trimethoprim alone had never been used in the practice, 29% of urinary tract pathogens were resistant to this drug. Ninety-six per cent of isolates of Haemophilus influenzae were sensitive to ampicillin. The overall results suggest that most infectious disease in rural general practice can be managed with a limited and inexpensive antibiotic regimen. Such a regimen is described.

Whooping cough after stopping pertussis immunisation.

An epidemic of whooping cough occurred in a rural practice in Shetland, containing 144 children under 16. Before July 1974 all children were immunised against pertussis, but after that date immunisation was stopped. Of the 134 children studied, 93 had been immunised. Sixty-five of the children developed whooping cough. The incidence of infection was similar in those who had and had not been immunised. The incidence was also similar in those born before and after July 1974. There was no evidence to support the routine use of pertussis immunisation in rural Shetland.

Respiratory syncytial virus in hospital cross-infection.

During an epidemic of respiratory syncytial (R.S.) virus in Newcastle upon Tyne 13 children developed R.S. virus infections while in hospital with other conditions. R.S. virus infection was also noted in four members of the staff. In two of the hospital wards outbreaks developed. All children infected with R.S. virus developed symptoms. The symptoms varied with age; two children aged 2 months or less developed colds, as did five children over 1 year of age. One child of 15 months with Werdnig-Hoffman disease, though suffering from a cold, later developed pulmonary collapse. All five children aged 3 to 8 months developed bronchiolitis. The effectiveness of special nursing in cubicles was probably diminished because adults with mild colds were excreting virus. The dangers of R.S. virus infection to other children in the ward, especially those with congenital heart disease, is emphasized.

Use of unabsorbed radioactive marker substances in a re-assessment of the radioactive triolein test of fat absorption.

The radioactive triolein test has been compared with two chemical methods for the assessment of fat absorption in a group of inpatients from general medical wards. The special feature of the investigation is the use of a radioactive faecal marker to measure the completeness of faecal collections during the investigation period. Estimations of unabsorbed (131)I triolein and faecal fat measured by the chemical methods were made on the same specimens. The results showed that only 48% of the patients provided a complete collection of faeces (defined as a recovery of more than 90% of the faecal marker). From these patients good correlations were found between the triolein absorption test and the two chemical methods.It is suggested that previous criticism of the radioactive triolein test may have been due to incomplete faecal collections causing false results.

Observations on clinical and immunofluorescent diagnosis of parainfluenza virus infections.

Immunofluorescent techniques have been applied to nasopharyngeal secretions for the rapid diagnosis of parainfluenza virus types 1, 2, and 3 infections. Seventy-five infections were found by isolation techniques; 55 of these had nasopharyngeal secretions taken and 53 were positive by direct examination. A comparison of the results of 60 neutralization tests with immunofluorescence applied to monkey kidney isolations showed complete agreement. Immunofluorescence appeared to be a satisfactory method for differentiating the various haemadsorption viruses. The importance of parainfluenza viruses and respiratory syncytial virus in croup was noted and the association of the parainfluenza viruses with acute respiratory virus infection was confirmed. The clinical relationship between respiratory syncytial virus and parainfluenza virus type 3 is discussed.