Invasive pneumococcal infection in South and West England.

Variation in the incidence of invasive pneumococcal disease across South and West England, in 1995, was measured through a survey of microbiology laboratories. A 100% response rate was achieved. The incidence by laboratory varied between 5.2 and 20.4 per 100,000 catchment population (P < 0.001). Adjusting for pneumococcal vaccine uptake rate in over 65 year olds, hospital admission rates, blood culture system used and for the age and sex structure of the population, did not account for this variation. When blood culture sampling rates were included in a logistic regression model, the variation between laboratories was much less and of lower statistical significance (P = 0.019). Higher rates of blood culture sampling were associated with a higher incidence of invasive pneumococcal disease. Consistently high sampling should be encouraged because a higher diagnostic rate should result in more selective prescribing of antibiotics, and secondly because improved ascertainment of severe pneumococcal infections is a prerequisite for the evaluation of new pneumococcal conjugate vaccines.

Active surveillance of health and safety in microbiology laboratories.

In microbiology laboratories highly infectious material is handled alongside complex and potentially dangerous equipment, and staff are therefore at risk of infections and accidents. Acts of parliament and regulations exist to protect staff in the workplace, including those exposed to biological agents. The current monitoring of health and safety in laboratories seeks to ensure that employers and employees comply with existing regulations, but this form of passive surveillance is of limited value because it does not highlight shortcomings in techniques, equipment, premises, or personnel. We propose a scheme for the surveillance of health and safety in microbiology laboratories that will actively seek information about laboratory incidents and practices, in order to enable appropriate preventive measures to be instituted.

Sensitivity of thermophilic campylobacters to R-type pyocines of Pseudomonas aeruginosa.

Strains of thermophilic campylobacters of human origin were examined for bacteriocine activity and for susceptibility to R-type pyocines of Pseudomonas aeruginosa. None of 50 strains inhibited the growth of any other strain, but 13 of 80 strains (16%) were sensitive to R-type pyocines. Absorption of one of the partially purified pyocine preparations with a sensitive strain resulted in the removal of pyocine activity and a decrease in viable count of the organism by 85%.

Isolation of thermophilic campylobacters from two populations of dogs.

Faecal samples were collected from newly impounded stray dogs and from dogs presented to a clinic by their owners. The dogs were categorised as strays or pets and their faeces as formed or unformed. The faeces were examined bacteriologically. Campylobacters were significantly (P less than 0.01) more frequently isolated from the faeces of the stray dogs but there was no significant difference between the frequency of isolation of the organism from formed or unformed faeces. The significance of this finding in relation to public health and animal health is noted.

Co-trimoxazole sensitivity testing: comparison of separate and combined disk agar diffusion techniques.

Five hundred and seven strains of bacteria isolated from the urine of patients with significant bacteriuria (more than 10(8) colony-forming units per litre) were tested for sensitivity to co-trimoxazole by the agar diffusion technique. Each organism was tested with a combined disk containing trimethoprim and sulphamethoxazole in a primary sensitivity test and, at a standardised inoculum, with both a combined disk and separate disks of trimethoprim and sulphamethoxazole. The results show that combined disk testing does not always indicate the sensitivity patterns of the organisms being tested.

Isolation of Neisseria lactamica from the female genital tract. A case report.

Neisseria lactamica was isolated from the genital tract of a young patient with a persistent vaginal discharge. Although infection with N lactamica occurs very rarely, the importance of complete biochemical identification of neisseriae is emphasised in view of the serious social and medicolegal consequences which could result from a misdiagnosis of gonorrhoea.

Mycoplasma pneumonia: failure of erythromycin therapy.

Two cases of mycoplasma pneumonia are described which failed to respond to prolonged treatment with erythromycin. The substitution of oxytetracycline therapy resulted in rapid clinical and radiological resolution.

An assessment of a reflectance meter system for measurement of plasma or blood glucose in the clinic or side ward.

The Reflomat System for rapid estimation of plasma or blood glucose concentration has been evaluated. The System gave a linear response throughout its analytical range and the recovery of glucose added to glucose-free plasma was 97-105%. Addition of sodium fluoride to plasma produced a 7-15% reduction in the estimated glucose concentration. Plasma glucose concentration estimated with the Reflomat agreed closely with results of a glucose oxidase and a hexokinase based method, and blood glucose concentration measured with the Reflomat agreed well with results of a glucose oxidase method.

A rapid method for the measurement of plasma glucose concentration.

A modification of the manual glucose oxidase-gum guaiacum method of Shipton, B., Wood, P.J. and Marks, V. ((1975) Med. Lab. Tech. 32,33), for use with plasma, is described. The method enables rapid measurement of plasma or serum glucose concentration between 1 and 22 mumol/1 using 10 mul of sample and a single colour reagent. Experience of the method in routine use has shown that the coefficient of variation, beteen batch, is 2.1% and the time taken for analysis of 1 sample, standards and a quality of control sample is 12 min (including centrifugation of blood to obtain plasma).