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Plasmid profiling and digestion of amplified PCR product of ureA genes were used to determine genomic variation in 56 strains of Helicobacter pylori isolated from patients with peptic ulcers and subjects with gastritis recruited in Lagos and Ife, Nigeria. Twenty-five (45%) of the strains were found to harbour plasmids ranging in size from 0.9 kb to > 10 kb. The plasmid profile was able to detect differences between the strains, and also to distinguish between different strains isolated from the same patient. The expected amplified ureA gene PCR product was detected in all strains and digestion with the restriction enzyme DdeI did not produce discrimination amongst the strains, however, digestion with MluI produced little discrimination amongst strains. In conclusion, plasmid profiling produced better discrimination amongst H. pylori strains than ureA PCR gene profiling.

Four hundred and thirty five stomach mucosal biopsies were taken from 145 consecutive patients (3 from each patient) during investigations for dyspepsia in three hospitals in Western Nigeria. The aim was to determine the best suited rapid screening method to aid fast diagnosis of ulcer/gastritis in this environment, using Gram stain, CLO test kit (urease production test) and culture methods. Eighty-nine (61.4%) biopsies were positive using Gram stain, 61 (42.1%) using CLO test kit and only 28 (19.3%) using culture. Based on the various limitations of CLO test kits and culture methods, Gram stain was adjudged the best suited rapid method. The clinical implication of this finding is discussed.

Samples (98 plaque and 72 saliva) from 93 patients with dental caries were investigated for Lactobacillus species which comprised 65 (62.5%) of 104 isolates. Yeasts (20.1%), Streptococcus spp. (8.7%), Staphylococcus spp. (2.9%) and a few unidentified species (5.8%), were also found. The Lactobacillus isolates were L. brevis (24.6%) L. fermentum (18.5%) L. casei (16.9%), L. delbrueckii (15.4%), L. plantarum (9.23%), L. acidophilus (7.69%), L. jensenii (4.62%), L. salivarius (1.54%) and L. gasseri (1.54%). The most common species was L. brevis (24.6%). The strains tested for beta-lactamase production showed 75.4% positive. All the Lactobacillus strains were tested for bacteriocin production against Escherichia coli, Salmonella spp., Shigella dysenteriae, S. sonnei, Klebsiella spp. and Campylobacter sp. All the lactobacilli except L. jensenii produced bacteriocin against at least one of the indicator organisms. The involvement of Lactobacillus in dental caries was established, although its role and mechanism is not well understood. The ability of Lactobacillus spp. to protect their host against certain diseases by inhibiting the growth of potential pathogens was evident.

The prevalence of sorbitol-nonfermenting Escherichia coli O157:H7 (EHEC) was assessed in 100 patients with diarrhoea by stool culture on sorbitol MacConkey agar. The cytotoxicity of the EHEC strains was analysed by Vero cell assay and the antimicrobial susceptibility pattern of the isolates was determined. Detection rate of EHEC O157:H7 was 6%. Five of the six patients were males. Three of the isolates were from children and one was from a teenager. All strains induced cytotoxic effects in the Vero cell assay. All isolates were susceptible to most of the antimicrobials tested. The results showed that diarrhoea caused by EHEC O157:H7, a potentially life-threatening pathogen, has remained common particularly among the child population of Lagos during the past 10 years (5). There must therefore be adequate meat and food inspection to improve the general hygiene of local fast food restaurants, so-called 'bukkas', which are regarded as likely sources of infection.

Infections of domestic and wild animals that are transmitted directly or by an arthropod vector to humans are a major cause of morbidity and mortality worldwide and particularly in Nigeria. With a population of over 100 million and the need for improved health care delivery, Nigerians are at considerable risk considering the seriousness of these infections. Zoonotic infections that are endemic in Nigeria include tuberculosis, trypanosomiasis, toxoplasmosis, taeniasis, rabies, lassa fever and yellow fever. Zoonotic food-borne infections (caused by Campylobacter, Salmonella and Escherichia coli O157:H7) and cryptosporidiosis are emerging. Sporadic cases such as strongyloidiasis, ascariasis, leptospirosis, scabies, pentastomiasis and African histoplasmosis have been reported. There is a need to determine the prevalence of tick-borne zoonoses. Prevention and control of zoonoses in humans is by vaccination, treatment and health education. As a first measure to improve control, the link between veterinary and medical officers, which is presently very weak, needs to be strengthened. Furthermore, regional multidisciplinary approaches to the control of zoonotic infections should be adopted in West Africa, which take into consideration the huge inter-border traffic.

A total of 635 clinically diagnosed typhoid fever patients were bled from three different health institutions in the metropolis of Lagos, Nigeria over a period of 15 months, May 1997 to July 1998. Out of the total blood cultured, 101 (15.9%) isolates of Salmonella species were isolated of which 68 (67.3%) were S. typhi, 17 (16.8%) and 16 (15.8%) were S. paratyphi A. and S. arizonae respectively. The overall isolation rate of S. typhi among patients is 10.7%, with most isolates 45.9% found among the severely-ill young adults, age group 16-30 years. All isolates were subjected to anti-microbial susceptibility testing using 12 different antibiotics: chloramphenicol, ampicillin, cotrimoxazole, gentamicin, colistin sulfate, nalidixic acid, nitrofurantoin, cefotaxime, tetracycline, streptomycin, ofloxacin and ciprofloxacin. All the S. typhi and S. paratyphi A isolates showed resistance to two or more of the 10 of 12 antibiotics tested particularly the 3-first-line antibiotics commonly used (chloramphenicol, ampicillin and cotrimoxazole) in the treatment of typhoid fever in Nigeria. No isolate showed resistance to ofloxacin and ciprofloxacin, however, nalidixic acid and gentamicin showed a moderate and appreciable inhibition to most of our isolates.

Induction of subcutaneous abscesses in mice was used to study the pathogenicity of Prevotella bivia both in mono-infection and in mixed cultures with Escherichia coli and Peptostreptococcus spp. Virulence factors such as coaggregation and aggregate formation of cells, haemagglutination activity and tolerance to serum bactericidal activity were investigated for their possible role in P bivia pathogenicity. Monocultures of P bivia, E coli and Peptostreptococcus spp did not induce subcutaneous abscess at concentrations as high as 10(9) colony forming units/millilitre (cfu/ml). Only E coli persisted at the infection site for up to 7 days post infection but with a marked decline in cell count (8.0 x 10(2) cfu/ml). The anaerobic organisms did not persist at the infection sites beyond the fifth day. In contrast, mixed cultures of P bivia and E coli or all three organisms potentiated for infective abscess two weeks after infection. Viable cells were recovered from abscesses in greater numbers as the infection progressed. Prevotella bivia was the predominant organism in chronic abscesses while E coli predominated in abscesses in the acute stage of the infection. Prevotella bivia lacked haemagglutination activity against human and sheep erythrocytes and showed marked susceptibility to 50 per cent human serum. These may limit its haematogenous spread. Its ability to form aggregates in molar salt solutions and coaggregate with facultative organisms may account for its persistence in pathological sites.

Genomic DNA from 58 strains of Campylobacter made up of 48 Campylobacter jejuni and ten Campylobacter coli were digested with Sma I and analysed by pulsed-field gel electrophoresis (PFGE). The cleavage of DNA by Sma I gave 22 distinct hybridization patterns. The two Campylobacter species were subtyped by PFGE. The average genomic size for C. jejuni by Sma I digestion was 1.73 Mb, while that of C. coli gave 1.7 Mb. Results from this study indicate that PFGE analysis by Sma I digested genomic DNA provides a reliable means of differentiating between and within species of Campylobacter and provides a practical approach to epidemiological studies of Campylobacter.

Diversity, based on restriction fragment length polymorphism (RFLP) analysis, was studied in 48 strains of Campylobacter, comprising 27 chicken and 21 human strains of C. jejuni and C. coli, using genomic Southern hybridisation. Restriction digests of chromosomal DNA were prepared by treating with HaeIII and probed using a C. jejuni DNA probe. Nineteen distinct hybridisation patterns were identified, and differences in hybridisation pattern between members of the two species, and in individual strains of the same species, were seen. The method described proved more discriminatory than the Penner serotype, as strains from the same serotype were distinguished. The relative simplicity of the patterns obtained, together with the apparent diversity identified among individual strains and species, suggests that DNA fingerprinting using the C. jejuni DNA probe could be a useful identification method in epidemiological studies of Campylobacter infection in Nigeria.

Background: In Nigeria, with a rising incidence of diabetes mellitus (DM), there are no controlled studies of specific psychiatric morbidity among sufferers., Objective: To assess the prevalence of specific psychiatric disorders and general cognitive impairment in patients with diabetes mellitus., Method: Using Wing's Present State Examination and the Mini-Mental State Examination, we assessed the prevalence of specific psychiatric disorders and cognitive impairment among 100 DM patients attending an out-patient clinic, in comparison with a matched non-clinic sample; and examined the relationship between psychiatric morbidity and clinical variables., Results: They were predominantly males (66%), mean age 43.0 years, mean duration of illness, 7.7 years and in low level occupations. Only 11 of the patients had sexual dysfunction (11%) and psychiatric symptoms (31%). Psychiatric diagnosis (ICD-10) were, generalised anxiety (6%) and mild depressive disorder (4%). Two had subjective memory disturbance. Insulin-dependent patients had significantly more widespread psychiatric symptoms than the non-insulin dependent. Psychiatric symptomatology was significantly associated with low occupational status, duration of illness and sexual dysfunction., Conclusion: Health education, subsidizing the cost of treatment, and physicians' sensitivity to the emotional condition of patients, will help to relieve psychic distress and make for more adequate management.

Flagellin gene sequence polymorphisms were used to discriminate amongst 53 strains of Campylobacter jejuni and C. coli. The Campylobacter strains were made up of forty-three strains of Campylobacter jejuni and 10 strains of Campylobacter coli. The results were analysed in relation to Penner serotyping. Twenty DNA PCR-RFLP patterns (genotypes) were identified by analysis of Dde I fragment length polymorphisms in flagellin gene (fla A and fla B) polymerase chain reaction (PCR) products. Flagellin gene 13 genotype was a feature of 15% of strains, followed by flagellin gene 8 (9%). Differences in fragment patterns were observed not only between members of two species, but also between individual strains of the same species. The strains that were non-typable by the Penner serotype were distributed into 6 flagellin gene types. In conclusion, Ddc I fla typing is reproducible and offers high typability. However, when the scheme is used in combination with the Penner serotype it provides improved discrimination for the characterizing and subtyping of isolates.

Forty-three stool samples and rectal swabs were collected from diarrhoeic and 20 non-diarrhoeic patients under 5 years of age at various general hospitals in Lagos. A total of 110 faecal samples from animals (101 from chickens and 9 from pigs) were obtained from Mitchel farm, Agege and Oshodi--Isolo Local Government farms at Ejigbo. Campylobacter species were isolated from 6 (13.9%) of 43 children with gastroenteritis and none from 20 asymptomatic subjects. Forty-nine (48.5%) isolates from the hundred and one faecal specimen were isolated from chicken, while 3 (33.33%) out of 9 were from pigs. Campylobacter jejuni was the most prevalent accounting for 79% of the total isolates and C. coli accounted for 25%. All the human strains were gentamicin sensitive, while streptomicin and cloxacillin were resistant. Erythromycin had a high activity (83.3%) on human strains and only 59.6% activity on animal strains. About ten percent (9.6%) of the strains produced beta-lactamase.

Objectives: To determine the prevalence of bacteria that could cause diarrhoea in stool specimens of individuals with and without diarrhoea in both urban and rural areas of Nigeria. To ascertain the antibiotic susceptibilities of the bacterial diarrhoeagenic agents isolated. To document the predominant signs and symptoms associated with the various bacterial agents of diarrhoea., Design: Prospective study., Setting: Patients/individuals attending government and private clinics in Lagos, Edo and Cross-River States of Nigeria., Subjects: A total of 1,200 stool samples were collected from patients with diarrhoea. Another total of 1,200 stool specimens were obtained from controls., Results: For diarrhoea cases in urban areas Campylobacter spp. were more predominant (28%) and were followed by enteropathogenic Escherichia coli (EPEC) (28%) whereas in rural areas, EPEC were the most commonly isolated bacteria (18%), closely followed by Salmonella spp. (16%). Controls had a similar distribution pattern. Higher rates of isolation of these enteric bacteria were recorded among diarrhoea cases than in controls (p < 0.05). Diarrhoea due to Vibrio, Yersinia, Aeromonas, Plesiomonas and EPEC was mainly watery whereas it mainly consisted of blood/mucus for Shigella and Salmonella. All were associated with abdominal pain and fever. Results presented also indicate that over 80% of Shigella species, Salmonella, EPEC and P. shigelloides were susceptible to nalidixic acid and nitrofurantoin. Virtually all the enteropathogens were resistant to commonly used antibiotics such ampicillin, erythromycin, tetracyclines and streptomycin., Conclusion: Results show that distributional patterns of bacterial agents of diarrhoea may vary in urban and rural areas and have revealed the effectiveness of nalidixic acid, gentamicin and nitrofurantoin, in that order, against these enteropathogens.

The reactiviteisofstrains ofPlesionmona shigeloides, Campylobater jejuni, Campylobacter coli and Aeromonas species with some lectins namely Soyabean agglutinin (SBA), Ricinus communis agglutinin (RCA), Peanut agllutinin (PNA), Cancanavalin-A (Con-A), Lima bean agglutinin (LMA) and Abrin were investigated using the microtitre plate method. The results obtained show that all stains of A. hydrophila, A. caviae, A. Sobria and P. shigelloides reacted very strongly with PNA and SBA. All strains of C. jejuni studied failed to react with SBA but reacted with PNA Whereas C. coli did not show any reaction towards PNA but reacted very strongly with SBA. All strains of the different organisms were strongly agglutinated by RCA and LMA except A. Hydrophilia and A. sobria which did not react with RCA and LMA respectively. C. jejuni was not agglutinated by Con-A unlike C. coli. Only C. jejuni, C. coli and P. shigelloides reacted with abrin. This study suggests that the reactivities of lectins with the diarrheogenic bacteria studied may be used for their presumptive identifications and for epidemiological purposes.

Diversity based on ribosomal RNA gene-restriction endonuclease digest patterns was detected amongst forty-seven strains of Campylobacter made up of 38 strains of Campylobacter jejuni and 9 strains of Campylobacter coli. Restriction digests of chromosomal DNA prepared by treating with Hae III were probed with an oligonucleotide specific for Campylobacter 16S ribosomal RNA genes. Seventeen distinct hybridization patterns, each indicating the presence of 2-4 copies of the 16S rRNA gene are encoded in Campylobacter DNA. Differences in fragment patterns were observed not only between members of two species, but also between individual strains of the same species. Ribopattern fragments of 8.71, 7.56, 2.81 and 1.0 kb were characteristic of the majority of C. jejuni, whereas 7.59 and 4.68 kb fragments were commonly present in C. coli. In conclusion, Hae III ribotyping was even more discriminatory than the Penner serotyping of C. jejuni and C. coli, as strains of the same serotype were distinguished.

A total of 2,400 stool samples comprising 1,200 from patients with diarrhoea (600 each from urban and rural area) and 1,200 similarly divided controls were obtained from school children and clinic attendants of government and private clinics around three designated study centres of Edo, Lagos and Cross River states, Nigeria. These were screened for the prevalence of bacteria that could cause diarrhoea. Diarrhoea cases in urban areas had a high prevalence rate for Campylobacter spp. (28%), followed by enteropathogenic Escherichia coli (22%), Salmonella spp. (17%), Shigella spp. (14%), Aeromonas spp. (5%), and Yersinia enterocolitica (4%), whereas in rural areas E. coli was the most frequently encountered pathogen (18%), followed by Salmonella spp. (16%), Aeromonas spp. (15%), Shigella spp. (9%), Campylobacter spp. (8%), and Plesiomonas shigelloides (8%). A similar distribution but with lower rates was noted for controls in both urban and rural areas, however, no P. shigelloides was isolated. Results highlight a possible difference between the prevalence of enteric bacteria in rural and urban areas and reveals the strong association of Aeromonas and Plesiomonas species with cases of diarrhoea in Nigeria.

Fifty-eight Compylobacter strains were isolated from children with diarrhoea at various health centres in Lagos and from healthy chicken. Twenty-nine strains of Campylobacter were isolated from humans, while the same number were isolated from chicken. The strains were biotyped using the modified Preston biotype scheme. The Preston biotyping results have been compared with the results of Penner serotyping. Out of fifty-eight strains studied, the technique identified ten strains (17%) as C. coli, three (5%) as C. lari and fourty-five (78%) as C. jejuni, by the coding system. This technique identified twenty-eight Campylobacter species. This method highlights the usefulness of this technique in the biotyping of local strains, however, when the two schemes are used in combination they give excellent typing results suitable for epidemiological purposes.

Objective: To determine the prevalence, antimicrobial properties and beta-lactamase production of haemolytic enterobacteria in patients with diarrhoea and urinary tract infections in Lagos, Nigeria., Design: Hospital based prospective study., Subjects: Total of 324 patients comprising 194 diarrhoeal and 130 urinary tract infection (UTI) cases., Main Outcome Measures: Production of haemolysms. beta-lactamase and antibiograms of isolates., Results: 186 (57.41 pc) of the 324 clinical specimens screened were positive for enterobacteria, out of which 29 (15.59 pc) were haemolytic. Proteus vulgaris (2.78 pc) Klebsiella spp. (1.85pc). Escherichia coli (1.23 pc). Pseudomonas spp. (0.93 pc). Yersinia enterocolitics and Morganella morganii (0.62 pc). Salmonella spp. Vibrio cholerae and Proteus mirabilis (0.31pc) were the haemolytic enterobacteria Isolated. The susceptibilities of haemolytic bacteria to eight antibotics determined by disc-agar diffusion technique revealed that all 29 (100 pc) haemolytic isolates were sensitive to gentamycin and streptomycin but showed varied susceptibilities to the other drugs. Eleven (37.9 pc) of the 29 isolates produced beta-lactamase., Conclusion: We conclude that gentamycin and streptomycin are effective drugs against haemolytic isolates from diarrhoea and UTI cases.

The susceptibility of 40 clinical isolates of Prevotella bivia to 11 anti-anaerobic agents was determined by disk diffusion and agar dilution methods in accordance with the NCCLS (1990) recommended guidelines. With the disk diffusion method all the P. bivia tested were susceptible to rifampicin, cefoxitin, chloramphenicol, clindamycin and metronidazole. Twelve (30%) isolates were resistant to cefotaxime and ceftriaxone while 2 (5%) each were resistant to tetracycline and erythromycin. Worthy of note, 39 (97.5%) and all 40 (100%) isolates were resistant to ampicillin and penicillin respectively. Determination of minimum inhibitory concentrations (MIC) showed that the first set of 5 antibiotics, except rifampicin, were shown to be as active against all the strains tested as with the disk diffusion sensitivity method: cefoxitin, chloramphenicol, clindamycin and metronidazole had MIC90 values ranging from 0.5-1 microgram/ml. The MIC90s of erythromycin and tetracycline were 4 micrograms/ml each while the range of MIC of cefotaxime and ceftriaxone was 0.5-32 micrograms/ml with a MIC90 of 8 micrograms/ml, well below their breakpoints, which is somewhat at variance with disk diffusion results. The clinical significance of this, however, is not clear, especially in the absence of controlled clinical trials. Ampicillin and penicillin MIC90 values were 64 micrograms/ml and 80 U/ml respectively which essentially confirmed the resistance observed by the disk method. All the P. bivia isolates were beta-lactamase producers, hence the resistance of these isolates to penicillin and ampicillin. It is conceivable that in infections with monoculture of P. bivia, agents like tetracycline, or erythromycin may still be a useful alternative for treatment.

Two thousand four hundred stool samples comprising 1 200 each from diarrhoeal and non-diarrhoeal (control) cases with 600 of each category from urban and rural areas were screened for the prevalence of Aeromonas and Plesiomonas species in the different groups. Thirty (5 pc) and (14,8 pc) of Aeromonas species and 14 (2,3 pc) and 46 (7,7 pc) of Plesiomonas shigelloides were isolated from urban and rural areas respectively for diarrhoea cases. Only eight (1,3 pc) and 18 (3 pc) of Aeromonas spp. from urban and rural areas respectively and none of P. shigelloides were isolated from controls. Both organisms were more commonly associated with females than males. This may be attributable to the fact that both organisms are environmental water bacteria and in rural areas, because females engage more in domestic activities than males have more frequent contacts with the water sources such as rivers, streams, ponds. Most rural areas lack piped water supply. Diarrhoea due to both organisms was associated with fever and vomiting: mainly watery but mucoid and bloody stools were also noted. Antiobiogram of isolates showed over 70 pc resistance to ampicillin and streptomycin in both rural and urban areas whereas over 90 pc of both organisms were sensitive to nalidixic acid and gentamycin in urban and rural areas. Antibiogram of isolates was independent of age, sex and area of residence. Finally, for cases of infections due to Aeromonas spp. and P. shigelloides, the use of gentamycin, nalidixic acid and nitrofurantoin would be appropriate in both urban and rural areas.

Semi-quantitative and qualitative bacterial assessment of the vaginal and cervical flora of a total of 202 women was carried out over a period of six months to determine the bacterial flora in three groups of women and changes caused by prior use of antibiotics. The number was made up of 32 healthy volunteers, 80 women with gynaecological problems and 90 women with gynaecological infections who had had antibiotic treatment prior to this study. Standard methods were used for the investigations. Five main genera of anaerobic bacteria were isolated from all patients. They included, the Bacteroides spp., Prevotella spp., Porphyromonas spp., Peptostreptococcus spp. and Clostridium spp. Five non-sporing gram negative anaerobic bacteria constituted the bulk of the flora including Prevotella bivia, P. disiens, P. melanogenica, P. asaccharolytica and B. fragilis. The predominant flora was P. bivia occurring in 61 pc of cervical swab specimens of the 80 women with proven gynaecological infections who had not used antibiotics and accounting for 27 pc of the total number of Gram-negative anaerobic bacteria isolated. Escherichia coli and Staphylococcus epidermidis were the most frequently encountered aerobic bacteria. The semi-quantitative counts of the different bacterial species in the patient group were significantly higher than in the control group of healthy individuals (p < 0,025). Similarly, prior antibiotic administration significantly reduced the population and quantitative count of the anaerobic bacteria.

One hundred and forty-five stool samples from children with diarrhoea at various health centres in Lagos were investigated for Campylobacter jejuni/coli. These organisms were isolated from 24 samples (16.5%). They were later biotyped as 23 C. jejuni and one C. coli. Previous studies (3,6) recorded isolation rates of 5.2% and 11% respectively. No Campylobacter species was isolated from 100 control patients who did not have diarrhoea. Diarrhoea due to Campylobacter jejuni/coli is still common in males, and the ration of males to females is still 2:1 but the isolation rate is now 11.7%:4.8%. All the isolates of Campylobacter jejuni are still from children under two years of age. Campylobacter jejuni biotype 1 accounted for 52.5% in an earlier study (18), but accounted for 87.5% in this study. Serogroup 29(70.8%) was the commonest in this study, whereas serogroup 36(20.7%) was very common in an earlier study(18). Erythromycin, which is the drug of choice for the treatment of campylobacter enteritis, had 82% sensitivity to the organism(6) but in the present study only 20.8% of the isolates were sensitive to the antibiotic. Betalactamase production was detected in 12.5% of the isolates as against 6.4% earlier reported(17).

Campylobacter jejuni (10(8) C.F.U) fed intragastrically unto 18 laboratory rats (white whiskers) resulted in colonization of the 18 rats intestines and their eventual excretion of the organism for four months post infection. When 10(8) CFU of C. jejuni was mixed with 10 mu/ml of cadmium chloride (CdCl2) and fed immediately to another set of 18 rats, colonization of rats intestines was greatly reduced and C. jejuni was recovered from two (11%) out of 18 rats and the faeces were positive for C. jejuni for a maximum of 29 days. Six control rats given 1 ml of phosphate buffered saline (PBS) and a second set of another six control animals given 1 ml of PBS containing 10 micrograms/ml of CdCl2 gave negative result for C. jejuni throughout the experiment. This work depicts an in vivo effect of CdCl2 on C. jejuni and may be of importance in the control of C. jejuni colonization in experimental animals.

Antibiotic susceptibility testing and plasmid screening of 50 local isolates of Campylobacter coli and Campylobacter jejuni were done. All isolates were sensitive to ofloxacin but were resistant to ampicillin, cloxacillin, penicillin, streptomycin and aztreonam. A large number of isolates were sensitive to nalidixic acid (96%), ceftriaxone (96%) and chloramphenicol (86%). It is noteworthy that nine (18%) of the isolates were resistant to each of erythromycin, 15 (30%) were found to harbour plasmid DNA ranging in sizes from 2.0 to 45 megadalton. Resistance to tetracycline in one isolate was associated with the carriage of a 45-megadalton plasmid.

Clinical and environmental isolates of Vibrio parahaemolyticus were examined for their ability to agglutinate human and rabbit erythrocyte and to adhere to human buccal epithelial (HBE) cells in the presence or absence of mannose. All strains produced cell-associated haemagglutinins (HGs) after 3 h at 37 degrees C. Mannose-sensitive haemagglutination (MSHA) appeared to be a significant marker for differentiating between clinical and environmental isolates; 75% of clinical and 11% of environmental isolates exhibited MSHA with rabbit erythrocytes. All strains showed mannose-resistant adhesion (MRA) to HBE cells whose pattern had no relationship to the epidemiological source of the isolates. Adherence to HBE cells correlated with haemagglutination (HA) capability of environmental but not clinical isolates. This suggests that although intestinal adherence may be an essential step in vibrio colonization, it may not be a sufficient prerequisite for the subsequent expression of pathogenicity in Vibrio parahaemolyticus.

Oral infection of rats with 10(6)-10(8) colony forming units per ml of Campylobacter jejuni resulted in prompt intestinal colonization. Campylobacter jejuni was recovered from rat faecal samples for four months post infection. The colonized rats did not succumb to clinical diarrhoea or pyrexia. The resistance of rats to C. jejuni clinical infection and their ability to shed the organism for protracted periods, make rats potential source of zoonotic campylobacteriosis.

Mice were orally and intragastically challenged with standard suspensions containing 1 x 10(9-10) Colony Forming Units (C.F.Us) per ml of strains "2" and "5" of Campylobacter jejuni isolated in Lagos. Another group of mice received the same amount of C. jejuni and 1pc iron-dextran which was incorporated into the bacterial suspension ad Mueller-Hinton broth. Two sets of control mice were included in the study. One set received only 0.2 ml of phosphate buffered saline while the second set received a mixture of killed C. jejuni and 1pc iron-dextran. A standard control organism (C. jejuni) NCTC strain 11168 was included in the study. Results presented show that infection of mice with only C. jejuni did not result in clinical diarrhoea or death of the animals as was also observed in the two sets of control. However, when the mixture of 1pc iron-dextran and C. jejuni was given, 15 (75pc) and 13 (65pc) of twenty mice each given by infant mouse infection and intragastic challenge respectively died. All the surviving animals developed diarrhoea. The difference in this result when compared with controls and those that received only C. jejuni was statistically significant (P less than 0.05). Incorporation of iron-dextran into C. jejuni suspension in the Mueller-Hinton broth enhanced virulence of the organism.

A total of 354 (8%) out of 4395 primary school pupils located in seven Lagos primary schools were positive for beta-haemolytic streptococci (BHS). Eighty-three (23%), 99 (28%) and 113 (32%) of the respiratory tract isolates and 25 (53%), 14 (30%) and seven (15%) of the skin-lesion isolates were identified as belonging to Lancefield groups A, C and G respectively. Prevalence rate of BHS in a rural school was different from that in urban schools.

Campylobacter enteritis is endemic in Nigeria as in most other developing countries of the world. This paper examines the common biotypes and serogroups of Campylobacter in human and animal isolates. The observed correlation suggests a possible animal to human route of infection in Nigeria. Implications on preventive and control measures are discussed.

One hundred and thirteen rectal swabs and 87 faecal samples obtained from the Paediatric casualty of the Lagos University Teaching Hospital, Lagos, Nigeria were processed for Campylobacter jejuni/coli. Twenty-two (11%) of the specimens were positive for C. jejuni. Biotyping results showed that nine (41%) and eight (36%) belonged to C. jejuni biotypes I and II respectively, while three (14%) and two (9%) belonged to C. coli biotypes I and II. Serotyping results revealed that C. jejuni biotypes I and II and C. coli biotypes I and II belonged to different serotypes with serotypes A9 and A36 being the most prevalent. In-vitro antibiotic sensitivity testing using the disc method showed that 18 (82%) of the Campylobacter jejuni/coli isolates were sensitive to erythromycin and nalidixic acid, while 16 (73%) were sensitive to streptomycin. All were resistant to penicillin, while four (18%) and six (27%) were sensitive to tetracycline and cloxacillin respectively. We therefore recommend the use of erythromycin and streptomycin for cases of Campylobacter enteritis requiring antimicrobial therapy in Lagos, Nigeria.

Six serotypes were found among haemolytic streptococci of Lancefield-group G. Members of these types accounted for about one-third of the strains isolated from human infections and carriers in Nigeria. The type antigens were similar to the M-protein antigens of group-A streptococci in that they were associated with the ability of the streptococci to survive and multiply in fresh human blood unless specific antibody was present. It was also possible to demonstrate in these group-G streptococci and non-type-specific M-associated protein similar to that formed by M-positive strains of group-A streptococci.

Seventy patients with acute diarrhoea and sixty asymptomatic children in Lagos, Nigeria were screened for complement fixing and agglutinating antibodies to Campylobacter jejuni in wells of microtitre plates using automatic microtitre pipettes. Out of the seventy patients with acute diarrhoea, 55 (78.6%) had complement fixing antibody, while 48 (68.5%) had agglutinating antibody in their sera. Twenty-nine (48.3%) and 21 (35%) out of the sixty asymptomatic children screened had complement fixing and agglutinating antibody respectively. Generally 84 (64.6%) of 130 children (both symptomatic and asymptomatic) had antibody to C. jejuni in their sera. The difference in the incidence rate between the symptomatics and asymptomatic is not statistically significant. The result suggest an antibody response to C. jejuni among children with diarrhoea, indicating that most of the diarrhoea cases in our environment may be due to Campylobacter but the successful demonstration of antibody response to C. jejuni among asymptomatic individuals may also suggest that even "normal" individuals have in their sera, antibody that can agglutinate C. jejuni in Nigeria. Use of antibody responses alone to C. jejuni in the diagnosis of C. jejuni infections in Nigeria should therefore be interpreted with caution.

Clinical isolates of Neisseria gonorrhoeae, Campylobacter jejuni, Escherichia coli, Shigella dysenteriae, Shigella boydii, Yersinia spp. and Salmonella spp. were screened for the presence of plasmids. Approximately 80% of these strains harboured plasmids ranging in molecular weight from 1.0 to 45 x 10(6) daltons.

5,576 people who had two or more of the following symptoms, running nose, cough, fever and crepitations/rhonchi over the chest were interviewed. 1,355 specimens of nasal and throat swabs from those interviewed were processed for viruses associated with upper respiratory tract infection. There was a sharp rise in 'flu-like symptoms in March 1976, followed by a much higher incidence from June, reaching a peak in August. Influenza A was isolated from most of the specimens collected. A few para-influenza II were also isolated. Our findings show that severe outbreaks of acute viral infection of the respiratory tract occurred during our wet season particularly around August.

In an epidemiological study of enteropathogenic Escherichia coli, 102 strains were isolated from patients seen at the University Teaching Hospital in Lagos. The most common serotype encountered was 055 followed by 026. Antimicrobial susceptibility testing and plasmid profiling of the strains were done. All the strains were sensitive to colistin, nalidixic acid, nitrofurantoin, cefotaxime, amikacin, and augmentin. Of the 102 strains, 47 (46%) were resistant to one or more of the following antimicrobial agents: Co-trimoxazole, tetracycline, ampicillin, streptomycin, sulphonamide and a combination of ampicillin with sulbactam. All the strains that were resistant to any antimicrobial agents were also resistant to tetracycline. Seventy-two strains (70.6%) harbored plasmid whose molecular weights ranged from 0.8 to 120 x 10(6) daltons. The majority of the plasmid were smaller than 6 x 10(6); 90% of strains carrying plasmid ranging in size from 2 to 6 x 10(6) daltons and 50 to 70 x 10(6) daltons were resistant to one or more antimicrobial agents. Transformation and conjugation experiment showed that about 57% of the resistant strains carried R plasmid. Plasmid-determined resistance to tetracycline, ampicillin, streptomycin and sulphonamide was found.

Leg ulcers in 26 patients with sickle-cell disease (SCD) were studied bacteriologically over a period of 6 months. The average age of the patients was 20.92 years and the mean duration of the ulcers was 3.43 years. In order of frequency, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacteroides melaninogenicus were the predominant organisms. Anaerobes were isolated from 14 (54%) of 26 patients and represent 21% of the total 77 isolates. The presence of anaerobes correlated well with odorous ulcers. Isolation of anaerobes from leg ulcers of patients with SCD has added to knowledge of bacterial infection in SCD.

Limulus gelation assay and dermal Schwartzman reaction provided a sensitive and reproducible means of testing the endotoxic activity of hospital strains of Campylobacter jejuni in Lagos, Nigeria. All the 22 isolates of Campylobacter jejuni tested for the limulus gelation assay were positive for the production of endotoxin. Furthermore, the Campylobacter suspensions caused a positive dermal Schwartzman reaction in rabbits. The area of skin reaction was less extensive than that produced by Escherichia coli 01114B and E7539/77 which served as positive controls. Five local strains of Campylobacter jejuni tested for enterotoxin production showed negative reaction in the infant mouse test whereas enterotoxin production was observed in Campylobacter jejuni strain 11168 and Escherichia coli E7539/77. Consequently, the infant mouse test may not be suitable for enterogenicity testing of our local isolates of Campylobacter jejuni.

A large epidemic of urban yellow fever occurred in April and May 1987 in Oyo State, western Nigeria. The principal vector was Aedes aegypti, breeding in domestic water containers. The 1987 outbreak followed an epidemic of sylvatic yellow fever in eastern Nigeria the previous year, and probably resulted from introduction of the virus by viraemic travellers. The outbreak in Oyo State ended in early July, by which time 805 cases and 416 deaths had been officially notified. However, surveys of 3 villages in the epicentre, a region with over 4 million inhabitants, indicated an infection rate of approximately 20%, a clinical attack rate of 2.9% and a mortality rate of 0.6%, suggesting that the true incidence of cases and deaths far exceeded the official reports. Yellow fever virus was isolated from persons with fully developed yellow fever as well as mild febrile illness. One virus isolate was made from blood of an individual with mild illness, who had received 17D vaccine 5 d earlier; monoclonal antibody analysis showed that the isolate was a wild-type virus. Larval indices of Ae. aegypti were very high; however, low vector competence of the Ae aegypti population may have provided a constraint on spread of the epidemic. In late 1987 a third epidemic appeared in Niger State, northern Nigeria, with 644 reported cases and 149 deaths. The vector(s) involved is (are) unknown.

Twelve strains of Staphylococcus aureus were studied. All the strains were tested for penicillinase production by the iodometric and starch-paper methods. Ten out of 12 strains produced penicillinase. A strain which was gentamicin resistant and penicillinase producer was tested for synergism using the killing growth method. Synergism was observed between cloxacillin and gentamicin. These two antibiotics can now be used to treat infection by Staphylococcus aureus especially those that produce penicillinase and gentamicin resistant.