Multilocus sequence typing of Campylobacter jejuni and Campylobacter coli isolates from poultry, cattle and humans in Nigeria.

AIMS: To determine the genetic diversity of Campylobacter jejuni and Campylobacter coli isolates from Nigeria and to identify the association between multilocus sequence types and hosts (poultry, cattle and humans). METHODS AND RESULTS: Isolates were identified using multiplex PCR assays. Multilocus sequence typing (MLST) was used to determine the genetic diversity of 36 Camp. jejuni and 24 Camp. coli strains isolated from poultry, cattle and humans. Of the 36 Camp. jejuni genotyped, 21 sequence types (ST) were found, 9 (43%) were new while of the 24 Camp. coli isolates genotyped, 22 STs were identified with 14 (64%) being new. The most prevalent sequence type was ST1932 followed by ST1036 and ST607 while the prevalent clonal complexes were CC-828, CC-460 and CC-353. CONCLUSIONS: Campylobacter isolates from Nigeria were found to be diverse with novel genotypes. There was overlap of CC-828, CC-460 and CC-353 between the poultry, cattle and human isolates. Genetic exchange was also detected in two of the Camp. coli isolates. SIGNIFICANCE AND IMPACT OF THE STUDY: This study highlights the genetic diversity of Campylobacter strains in Nigeria, demonstrating that Camp. jejuni and Camp. coli isolates are diverse and have both local and global strains. The predominant sequence types and clonal complexes found in this study differ from other countries; this exemplifies that different predominant Campylobacter populations exist between countries.

Extended-spectrum beta-lactamase production among ampicillin-resistant Escherichia coli strains from chicken in Enugu State, Nigeria

One hundred and seventy-two ampicillin-resistant E. coli strains isolated from commercial chickens in Enugu State, Nigeria, were screened for beta-lactamase production using the broth method with nitrocefin® as the chromogenic cephalosporin to detect enzyme production. Beta-lactamase producing strains were further examined for extended-spectrum beta-lactamase (ESBL) production using the Oxoid combination discs method. One hundred and seventy (98.8 percent) of the 172 ampicillin-resistant E. coli strains produced beta-lactamase enzyme. Sixteen (9.4 percent) beta-lactamase producers were phenotypically confirmed to produce ESBLs. Six of the ESBL producing strains were only detected with ceftazidime versus ceftazidime/clavulanate combination while ten of the ESBL producers were detected with cefotaxime versus cefotaxime/clavulanate combination. Chicken may serve as a reservoir of ESBL-producing E. coli strains which could be transferred to man and other animals.

Cento e setenta e duas cepas de Escherichia coli resistentes a ampicilina isoladas de frangos em Enugu State, Nigéria, foram avaliadas quanto à produção de beta-lactamase através do uso de método em caldo com nitrocefin® como indicador cromogênico da produção da enzima. Em seguida, as cepas produtoras de beta-lactamase foram examinadas quanto à produção de beta-lactamase de espectro expandido (ESBL) através do método de discos combinados Oxoid. Entre as cepas de Escherichia coli resistentes a ampicilina, cento e setenta (98,8 por cento) produziram beta-lactamase. Testes fenotípicos indicaram que dezesseis (9,4 por cento) das cepas produtoras de beta-lactamase produziram ESBL. Seis cepas produtoras de ESBL foram detectadas apenas com a combinação ceftazidima versus cefotaxime/clavulanato, enquanto dez cepas produtoras de ESBL foram detectadas com a combinação cefotaxime versus cefotaxime/clavulanato. Frangos podem ser reservatório de cepas de E.coli produtoras de ESBL, que podem ser transferidos para o homem e outros animais.

Trypanosomosis in small ruminants maintained by low riverine tsetse population in central Nigeria.

The prevalence of trypanosomosis was investigated over a 12-month period, among small ruminants grazing in known sleeping sickness endemic area of central Nigeria and under light riverine tsetse challenge. Analysis of the data from 304 Yankassa sheep and 239 West African DwarfxRed Sokoto goats indicated high mean prevalence (27.62%, confidence limits Cl: 0.232, 0.312). Interspecies difference between sheep (38.16%; 0.382, Cl: 0.332, 0.432) and goats (14.23%; 0.142, Cl: 0.102, 0.182) was highly significant (P<0.001). Infections were also significantly higher (P<0.05) with agro-pastoral (extensive) management, during the dry season and in adults compared to intensively managed animals, the wet season and young animals, respectively. Trypanosoma vivax was the predominant parasite encountered and accounted for over 49% of the infections. T. congolense and mixed populations were diagnosed at approximately 15% each while T. brucei were absent in caprines. The implications of these findings in the epidemiology of the diseases in both man and domestic animals is discussed.

Antimicrobial activity of methanolic extract of Solanum torvum fruit.

The methanolic extract of Solanum torvum fruit showed a wide spectrum of antimicrobial activities against human and animal clinical isolates.

Enterotoxigenicity of Salmonellae isolated from dogs in Nigeria.

Salmonella dublin, S agama and S typhimurium isolated from local dogs were tested for enterotoxigenic activity using Guinea-Pig Ligated Ileal Loop Technique. One millilitre each of whole-cell culture (WCC) and cell-free filtrate (CFF) of each isolate was injected into replicates of ligated loops. Enterotoxigenic activity, measured as mean dilatation index (DI) was determined for WCC and CFF of each isolate. Both WCC and unheated CFF of all the serotypes induced considerable fluid accumulation in the loops. The mean DI produced by WCC and unheated CFF varied significantly among the three serotypes. This variation seems to support the concept of multiple mechanisms for salmonella-induced diarrhoea.

Detection of antimicrobial residues in poultry meat and slaughter cattle in Nigeria.

The European four plate test (FPT) was used to establish whether and where antimicrobial residues accumulate in the tissue of commercial poultry and slaughter cattle in Nigeria. Bacillus subtilis and Staphylococcus aureus sensitive to different antimicrobials seeded on nutrient agar media at different pH levels were employed. Inhibitory residues were detected in the muscles, liver, and/or kidney of experimental local chickens, commercial broilers and layers and 2 of 24 slaughter cattle. The public health hazards of antimicrobial residues in developing countries are discussed.

Epidemiological aspects of outbreaks of food-borne salmonellosis in Scotland between 1980 and 1989.

Between 1980 and 1989, 2,212 outbreaks of food-borne infection were reported in Scotland. Of 2,073 episodes for which a causative agent was established, 1,732 (84%) were caused by salmonellae. An average of 980 people were affected each year, while the average number of individuals infected per general outbreak was 16.8. The infected foods were consumed outside Scotland in 25% of the outbreaks. In 75% of 1,107 episodes where the location was specified, the implicated foods were consumed in the home; hotels and restaurants accounted for 15%. Specific food items were identified in 603 (35%) of the 1,732 outbreaks; poultry meat was responsible for 332 (55%) and milk 49 (8%), while eggs accounted for 23 (4%) outbreaks.

Comparison of two enrichment media and three selective media for isolation of salmonellae from fresh chicken carcass rinse fluids and sewer swabs.

Slamonella was detected in 214 (45%) of 477 chickens examined. For Salmonella-positive samples of fresh chicken carcass rinse water a sensitivity of 96% and 29% respectively was demonstrated for Rappaport-Vassiliadis (RV) and Selenite broth. A similar superiority of RV was found for the sewer swab samples. Among the three selective agar media investigated a limited sensitivity (below 50%) was found making it imperative to use at least two media, one of which should be deoxycholate citrate agar.

The epidemiological relationship between Salmonella isolated from poultry meat and sewage effluents at a long-stay hospital.

Between February 1988 and March 1989 chicken carcases delivered to the kitchen of a long stay psycho-geriatric hospital were screened every week for salmonella contamination. While 214 of 477 (45%) individual carcases carried one or more salmonella types, every single consignment examined contained affected carcases. Simultaneously, sewers draining the residential accommodation and excluding kitchen effluent, were also monitored. Thirty out of 79 (38%) of Moore's swabs were positive for salmonella. There was a statistically significant association between the salmonella types isolated from chicken and those isolated from sewers the following week. Following a change in kitchen policy to order only cooked chicken there was a significant reduction in the isolation of salmonella from the sewers.

Salmonellae in the African great cane rat (Thryonomys swinderianus).

Because of its large size, the African great cane rat (Thryonomys swinderianus) is valued for food and has become a popular meat in western Africa. A survey was conducted to determine the occurrence of salmonellae in cane rats. Ten strains of Salmonella sp. were isolated from eight of 25 (32%) cane rats. Salmonella ajiobo was isolated from the spleen and intestines of three cane rats; S. agama was obtained from the spleen, liver and intestines of three animals; and S. poona was isolated from the spleen and liver of two cane rats. The occurrence of salmonellae in T. swinderianus is a potential public health hazard. Humans may become exposed to infection by consumption of inadequately cooked infected cane rat meat, or by eating vegetables, sugar cane and fruits contaminated with excretions of carrier cane rats. Incidents of human salmonellosis attributable to cane rat meat have not yet been reported; however, all three serotypes isolated from the cane rats have also been isolated from stools of patients suffering from gastroenteritis in Nigeria.

Poultry-borne salmonellosis in Scotland.

Between 1980-5, 224 outbreaks of salmonellosis associated with poultry-meat were reported in Scotland. In total 2245 persons were affected, 12 of whom died. Twenty-one salmonella serotypes were identified from those affected, while 33 serotypes were isolated from poultry during routine monitoring and disease investigation. Existing measures to prevent the spread of salmonellae within poultry flocks and processing plants are failing. It is suggested that irradiation of poultry-meat may be the only effective method of reducing the public health problem of poultry-borne salmonellosis.

Wall Geckos (Geckonidae) as reservoirs of Salmonellae in Nigeria: problems for epidemiology and public health.

An investigation was carried out to establish the occurrence of Salmonellae in household wall lizards (Gecko gecko and Hemidactylus sp.) in Nsukka, Nigeria. Twentyseven out of 90 geckos examined yielded positive Salmonella isolations, giving a carrier-rate of 30 per cent. While 2 isolates were non-typable, the other 25 strains belonged to 6 serotypes: Salmonella weltevreden (8 strains), Salmonella typhimurium, Salmonella enteritidis, Salmonella hvittingfos, Salmonella saintpaul, and Salmonella agama. Two serotypes, Salmonella weltevreden and Salmonella hvittingfoss are reported for the first time in Nigeria. The role of Geckonidae in the epidemiology of salmonellosis and the public health implications of geckoborn Salmonellae are highlighted.

A survey of salmonellae in trade cattle slaughtered at Nsukka abattoir.

A survey was carried out to determine the occurrence and carrier rate of Salmonella in trade cattle slaughtered for human consumption at Nsukka abattoir in Anambra State. Two hundred Zebu cattle were screened. A total of 424 specimens comprising of gall bladders, messenteric lymph nodes and rectal faeces were subjected to enterobacteriological studies. Identification of isolants was based on biochemical reactions and the use of polyvalent and group-specific antisera. Two Salmonella serotypes made up of Sal. typhimurium (3 strains) and Sal. dublin (5 strains) were obtained from 6 of the 200 cattle. A carrier rate of 3% was recorded. Two animals were carriers of Sal. typhimurium, while 4 cattle harboured Sal. dublin. Two strains of Sal. typhimurium and 3 of Sal. dublin were isolated from the gall bladder. The public health significance of the occurrence of anthropozoonotic Salmonellae in food animals as well as the hazard of consumption of bile are discussed.