Numerical classification of campylobacters by DNA-restriction endonuclease analysis.

Reference strains from five different species of Campylobacter were examined by DNA-restriction endonuclease analysis. The DNA profiles were resolved as absorbence peaks and converted to numerical values which were analysed by a Sirius microprocessor. The percentage similarity between each profile was calculated and the strains clustered together by the computer on shared similarities and the results displayed as an abbreviated dendrogram. Each of the species of Campylobacter were clearly separated from each other and the different biotypes within a species could also be differentiated.

Rat-bite acquired leptospirosis.

We report a case of leptospirosis in a boy following a rat-bite, an unusual mode of transmission for this infection. The use of antibiotics for fever following a rat-bite is discussed.

A comparison of live and formalised leptospiral microscopic agglutination test.

The sensitivity and reliability of a formalised leptospiral antigen battery was compared with a smaller battery of live leptospiral antigens with 152 human sera positive for leptospirosis. There was good concurrence of results between the formalised and live antigens, however the live battery did fail to detect some positive sera where the antibody level was low. The formalised antigens were more sensitive than the live (P less than 0.001) and more reliable in the detection of early leptospiral infection, but the live antigens were more specific in the determination of probable infecting serogroup.

Experimental infection of monkeys with Leptospira interrogans serovar hardjo.

Grivet monkeys experimentally infected with two different strains of Leptospira interrogans serovar hardjo showed no signs of severe clinical disease. There were no significant macroscopic lesions in any of the tissues examined, but the organisms were demonstrated in various tissues by immunofluorescent technique and were isolated from the blood and urine of two monkeys and the kidney of one. Abraded skin was shown to be a viable route of infection in non-human primates.

Serological study of leptospiral infections and endogenous uveitis among horses and ponies in the United Kingdom.

The prevalence of antibody titres to a range of 20 leptospira antigens in the serum of horses and ponies with no ophthalmic abnormalities and with ophthalmoscopic evidence of endogenous uveal inflammatory disease was determined using a microscopic agglutination technique. Titres against leptospira antigens were observed in 13 out of 138 (9.1 per cent) animals with no ophthalmic abnormalities, and in three out of 27 (11.1 per cent) animals with anterior uveitis. Serovar sejroe was common to all seropositive animals with anterior uveitis. The results show that leptospira infection is not a major factor in the aetiology of equine anterior uveitis in the UK, but suggests that the organism may be associated with some cases of recurrent anterior uveitis.

Comparison of the DIFCO and Patoc 1 slide antigens in the screening of leptospirosis.

A comparison of the Patoc 1 slide agglutination (SAT) and DIFCO slide agglutination test for the screening of leptospirosis in man, cattle and coypu (Myocastor coypus Molina) is reported. The economic costs, convenience and availability of the antigens for the tests are analysed. It is recommended that slide agglutination methods alone are not sufficient for the routine diagnosis of leptospirosis.

Isolation of leptospires from a one week dead coypu (Myocastor coypus Molina).

The isolation of L. Interrogans from a one week dead coypu is reported. The isolate was identified as a pathogenic strain of leptospira belonging to the Icterohaemorrhagiae serogroup.

The detection of leptospires by a chemiluminescent immunoassay.

Rabbit serum hyperimmune to Leptospira interrogans var icterohaemorrhagiae serovar icterohaemorrhagiae, reference strain RGA was conjugated to the chemiluminescent label ABEI (6-[N-(4-aminobutyl)-N-ethyl amino]-2,3-dihydrophthalazine-1,4-dione) in the presence of the coupling agent, EDC (1-ethyl-3(3-dimethyl amino-propyl)-carbodiimide HCl). The luminescent conjugate was incubated with homologous and heterologous antigens. The results indicate that chemiluminescence may provide an accurate and rapid method of detecting leptospires in biological fluids.

The coypu as a rodent reservoir of leptospira infection in Great Britain.

The coypu (Myocastor coypus Molina) is an aquatic rodent that has become a widespread pest in the south-east of England. Since the natural habitat of this animal is aquatic, the possibility of infection with leptospires was investigated. Twenty-nine coypu were trapped and examined by serological, histological and cultural methods. Of these, there was serological evidence of infection in seven coypus and Leptospira interrogans var. Wolffii was isolated from a further animal. This appears to be the first report of the isolation of leptospira from a coypu in Great Britain.

Survival of leptospires in commercial blood culture systems.

Laboratory diagnosis of leptospirosis depends on the serological findings and, if possible, the isolation of the organisms. During the period 1981-1982 there were 40 blood cultures submitted from serologically positive patients and a successful isolation rate of only 12% was attained. Correct media, method of collection of suspect blood and laboratory technique all contribute to the successful isolation of the organism. Because of the low isolation rate an investigation was undertaken of various blood culturing systems used in Great Britain. Results obtained showed that certain blood culture media were able to maintain the organism better and therefore increase the isolation rates of leptospira. Factors affecting the isolation rate are presented.

Failure of the fluorescent antibody reaction to identify penicillinase-producing gonococci.

The fluorescent antibody test is now widely used to confirm the identity of Neisseria gonorrhoeae but may fail to identify penicillinase-producing strains (PPNG). This problem arises when conjugates are used that incorporate only gonococci that are not penicillinase-producers. We have shown that conjugates prepared from mixtures of PPNG and non-penicillinase producing gonococci give good fluorescent reactions. This difference in the reactions of PPNG strains is clearly related to their penicillinase-producing abilities, further study of the antigenic relation between penicillinase production and the antigenic structure of N gonorrhoeae is evidently required.

Impaired bacteriological responses in babies after maternal iron dextran infusion.

The effect of a total dose infusion of iron dextran in pregnancy on 15 mothers and their babies was compared with 19 controls. The bacteriostatic effect and opsonising ability of the sera, of babies born to the treated mothers, were considerably impaired. This was associated with a significantly lower transferrin concentration in these mothers. Although these in vitro tests were not associated with an increase in overt infection during the perinatal period, they suggest the need for caution in the use of total dose infusions in pregnancy.