Comparison of three methods for culture confirmation of Neisseria gonorrhoeae strains currently circulating in the UK.

AIMS: To establish the current sensitivity of two commercial kits for culture confirmation of Neisseria gonorrhoeae strains circulating in the UK. METHODS: A total of 544 strains were studied (199 gonococci from male patients attending hospitals in the county of Avon, 204 unselected N gonorrhoeae isolates from male patients in Leeds, 20 strains referred to the Gonococcus Reference Unit because of difficulties with the Syva fluorescent antibody test (FAT), and 121 strains collected over a four year period which had not reacted with serotyping antibodies). Strains were tested by sugar utilisation in cysteine trypticase base agar (CTA test), the Phadebact Monoclonal GC Test and Syva MicroTrak Neisseria gonorrhoeae Culture Confirmation Test. The auxotype and serovar of each strain were also determined. RESULTS: The sugar utilisation test confirmed the identity of 99% (197/199) of gonococci from Avon and 97% (198/204) of those from Leeds. The Syva FAT confirmed 76% (151/199) of isolates from Avon and 84% (171/204) of those from Leeds. The Phadebact test confirmed all but one isolate from the 403 strains from both cities. Half of the 20 referred FAT negative isolates also give a negative result in the Syva FAT; however, only 10% of the remainder gave a strong reaction in our laboratory. All serotyping antibody negative strains were negative in the FAT, although all these and all of the 20 strains that give a negative result in the FAT gave positive reactions in the other culture confirmation tests. Typing tests revealed a greater diversity amongst the FAT negative strains from Leeds than those from Avon. CONCLUSIONS: Considerable differences in the sensitivity of the MicroTrak but not with the Phadebact or CTA tests were found for the identification of isolates from two geographically distinct areas of the UK. Our results suggest that the Syva FAT would not be suitable, if used alone, for culture confirmation in Avon or Leeds.

Salmonellosis associated with 'Combi-oven' cooked egg.

During July 1989, four cases of Salmonella enteritidis (later identified as PT24) infection were reported by laboratories in Bristol. All those infected had dined at a restaurant in the city. An epidemiological investigation revealed that a number of restaurant staff and 56 customers who had completed a questionnaire had also been ill with gastrointestinal illness. An association was found between illness and eating egg mayonnaise. A 'Combi-oven' egg-cooking technique has been identified as the most likely cause of this outbreak. In view of the widespread commercial use of this cooking method the evidence related to this outbreak is given in detail.

Laboratory detection of ciprofloxacin resistant Neisseria gonorrhoeae.

During 1989 and 1990 strains of Neisseria gonorrhoeae with reduced susceptibility to ciprofloxacin were isolated in laboratories across the United Kingdom. Treatment failures were associated with some of these infections. These strains were detected by quantitative susceptibility testing because the zone of inhibition around 5 micrograms ciprofloxacin discs shows little decrease in size even with those that are the most resistant. This study determined that strains with reduced susceptibility to ciprofloxacin (MIC of greater than or equal to 0.05 mg/l) produced no zone of inhibition around a commercially available disc containing 30 micrograms of nalidixic acid. Ciprofloxacin sensitive (MIC of less than 0.05 mg/l) strains, however, grew with a large zone (greater than 21 mm) around this disc. These observations suggest that laboratories could adopt this disc test to detect those strains for which ciprofloxacin is not appropriate treatment.

Penicillin-binding protein 2 genes of non-beta-lactamase-producing, penicillin-resistant strains of Neisseria gonorrhoeae.

Oligonucleotides that correspond to regions of the penicillin-binding protein 2 gene (penA) that differ between penicillin-sensitive and penicillin-resistant strains have been used as probes to classify the penA genes in a collection of penicillin-resistant gonococci isolated in Britain. 44/47 of those gonococcal strains that had minimal inhibitory concentrations of greater than or equal to 0.25 microgram benzylpenicillin per ml contained extensively altered penA genes which appeared to be very similar (or identical) to one or other of the two classes of altered penA genes that have been described previously. Since these two classes of altered penA genes are related, it appears that the great majority of the altered penA genes on non-beta-lactamase-producing penicillin-resistant gonococci have a clonal origin. The other three penicillin-resistant strains had altered penA genes that were different to those described previously. A crucial step in the development of the altered forms of PBP2 with decreased affinity for penicillin appears to have been the insertion of an extra codon within the transpeptidase domain of the penA gene. This insertion was found in the penA gene of all gonococci with minimal inhibitory concentrations of greater than 0.016 microgram benzylpenicillin per ml but was not found in any strains with minimal inhibitory concentrations of less than or equal to 0.016 microgram per ml.

In-vitro activity of enoxacin against gonococcal isolates in comparison with that of five other antibiotics.

The in-vitro activity of enoxacin was investigated against 305 clinical isolates of Neisseria gonorrhoeae, including both penicillinase-producing strains (PPNG) and non-penicillinase producing strains (NPPNG), and compared with the activity of cefuroxime, acrosoxacin, spectinomycin, benzylpenicillin and ampicillin. Enoxacin was more active than the other antimicrobials tested, with an MIC90 value for the NPPNG organisms of 0.08 mg/l and for the PPNG organisms of 0.16 mg/l. Ten of the 305 isolates tested were resistant to spectinomycin; MICs of less than or equal to 0.08 mg/l were obtained for enoxacin against these organisms.

An outbreak of meningococcal disease in Stonehouse: planning and execution of a large-scale survey.

In November 1986 a large-scale survey was undertaken in the Gloucestershire town of Stonehouse during an outbreak of meningococcal disease due to group B type 15 subtype P1.16 sulphonamide-resistant strains. There were 15 cases in Stonehouse residents during the 4 years from April 1983, an annual attack rate of 56.5 per 100,000. Four secondary cases occurred despite rifampicin prophylaxis. The objectives of this community survey were to investigate patterns of meningococcal carriage, transmission and immunity and to determine the proportion of non-secretors of blood group antigens in the Stonehouse population and amongst meningococcal carriers. A total of 6237 subjects participated including 75% of the 6635 Stonehouse residents. Over 97% of the participants provided all three of the requested specimens-nasopharyngeal swabs, saliva and blood samples. The co-operation between the many organizations involved in the detailed preliminary planning was instrumental in the success of the survey; in particular the value of effective collaboration between Departments of Community Medicine and Microbiology and of the Public Health Laboratory Service network of laboratories in undertaking investigations of this size and type was clearly demonstrated.

Epidemiology of resistance in Neisseria gonorrhoeae.

In the face of almost unique selective pressures many strains of gonococci have become increasingly resistant to antibiotics. Both chromosomal mutation and acquisition of plasmids are involved. However, whereas there have probably been multiple selections of many mutation events determining chromosomal resistance, evidence suggests that a very limited number of plasmid acquisitions has occurred, with subsequent spread within members of the species.

Outbreak of giardiasis associated with mains water in the United Kingdom.

An outbreak of giardiasis comprising 108 laboratory-diagnosed cases took place in Bristol in the summer of 1985. Epidemiological evidence indicated that the infection was spread via the municipal water supply.

Health risks of snorkel swimming in untreated water.

There are certain health risks associated with recreational exposure to bacteriologically polluted water. In this study, 27% (21/77) of swimmers who took part in a snorkel swimming event, experienced gastrointestinal symptoms within 48 hours of entering the untreated water. The incidence of these symptoms was statistically significantly greater than the incidence of such symptoms reported by two control populations (p less than 0.001), but not significantly different to 25% of people who had experienced gastrointestinal symptoms in a previous snorkel event in the same water environment. As the water quality came within the confidence intervals of the EEC standards for bathing water the adequacy of these standards needs further appraisal.

In vitro activity of temocillin against Neisseria gonorrhoeae including penicillinase-producing strains.

169 penicillinase-producing strains of Neisseria gonorrhoeae (PPNG) isolated in the United Kingdom were examined for susceptibility to temocillin and spectinomycin. A further 25 PPNG strains and 214 non-penicillinase-producing strains were examined against temocillin, spectinomycin, amoxycillin, cefuroxime and penicillin. Minimum inhibitory temocillin concentrations ranged from 0.36 to 5.0 mg/L with a mode at 1.25 mg/L. The distributions of sensitivities to other agents were in keeping with those previously described.