Characterization of Clostridium Species from Food Commodities and Faecal Specimens in Lagos State, Nigeria.

BACKGROUND: Food-borne pathogens are a major public health challenge worldwide. These organisms' cause illnesses leading to time loss in the work place and reduced productivity.Clostridium species cause infections through the production of powerful toxins which are responsible for diarrhoea and cramping. Diarrhoeal diseases due to Clostridia are one of the commonest worldwide but have hardly been reported in Nigeria. OBJECTIVE: This study characterized Clostridium species from food commodities and human faeces in Lagos State MATERIALS AND METHODS: Four hundred and twenty samples comprising food (220) and faecal (200) specimens in Lagos state were included in this study. Isolates obtained were identified using API 20-A and confirmed by Polymerase Chain Reaction assay and 16S rRNA sequencing. The food samples included meat and meat products, ready to drink traditionally prepared milk products, fresh vegetables, canned foods and local honey. RESULTS: Seventy (16.7%) Clostridium species were identified, 50 from food and 20 from faeces. Majority of the isolates were obtained from vegetables (56%) and meat products (34%). Of the 70 Clostridial species, 38 (54.3%) were C. perfringens, 5 (7.1%) were C. difficile and 2 (2.9%) were C. botulinum. All 38 (100%) strains of C. perfringens possessed alpha (cpa) toxin gene. CONCLUSION: Clostridium species are present in our environment and contaminate food products posing potential risks to consumers. There is therefore a need for these traditionally made street vended foods to be monitored because they are potential sources of food borne pathogens.

Arcobacter, an emerging opportunistic food borne pathogen--A review.

BACKGROUND: Arcobacters, emerging aetiologic agents of food-borne diarrhoeal illness in humans and animals are more frequently isolated in meat, especially poultry meat, pork and beef. Though human infection may exist, it has not been documented in Nigeria. AIM: This review presents an update of scientific information in Nigeria on arcobacters as an emerging food-borne pathogen of public health significance in Nigeria. METHODS: A comprehensive reviews of literatures was adopted to give an update on scientific findings on the disease in Nigeria. RESULTS AND CONCLUSIONS: The review revealed scientific evidences attributing the cause of human and animal illness to Arcobacter spp. It also highlights efforts towards the development of animal models where in virulence and pathogenicity of primarily A. butzleri and A. cryaerophilus isolated from human diarrhoeal stool samples were tested. This in turn elucidated the public health significance of this emerging food-borne pathogen. The review canvases for more investigation as to the role of arcobacters in food contamination and unrecognised food-borne disease in Nigeria.

Serum biochemistry and heamatological changes associated with graded doses of experimental Arcobacter infection in rats.

UNLABELLED: BACKGROUND; Arcobacters have unusually wide range of habitats, and some species can be human and animal pathogens OBJECTIVE: This study was designed to assess the haematological and biochemical changes associated with experimental Arcobacter infection in adult albino rat. METHODS: The pathogenicity of Arcobacterbutzleri and A.cryerophilus, isolated from the caecal content of healthy chicken and confirmed by multiplex PCR was tested in albino rats (Rattusnovegicus). Seventy-five healthy adult male rats, subdivided into 5 rats per group, challenged orally with a single dose of 10⁻³ - 10⁻9 cfu/ml of bacterial strains and another group of five uninfected rats served as control. RESULTS: Experimental infection resulted in diarrhoea,electrolyte imbalance and alteration of heamatological values. The packed cell volume (PCV), platelets, neutrophils and lymphocytes of the experimentally infected albino rats were significantly higher than those of the control group. CONCLUSION: This study showed that Arcobacter could be a potential pathogen in albino rats while the selected haematological and electrolyte parameters may be good diagnostic indicators of the animal response to the bacterial infections.

Prevalence of multiple drug resistance and screening of enterotoxin (stn) gene in Salmonella enterica serovars from water sources in Lagos, Nigeria.

OBJECTIVE: To determine the prevalence, antibiotic resistance and carriage of enterotoxin (stn) gene among strains of Salmonella isolated from water sources in Lagos. STUDY DESIGN: A total of 200 samples (60 well water, 60 pipe-borne water and 80 different brands of sachet water) were collected at random from various locations in Lagos. METHODS: The samples were evaluated bacteriologically using standard methods. The identified isolates were subjected to antimicrobial susceptibility tests and were further screened for the presence of stn gene using standard procedures. RESULTS: Thirty-seven of the samples analysed were positive for Salmonella isolates. Seven serotypes were found -Salmonella typhi (n = 3, 8.1%), Salmonella typhimurium (n = 8, 21.6%), Salmonella choleraesuis (n = 5, 13.5%), Salmonella enteritidis (n = 9, 24.3%), Salmonella paratyphi (n = 8, 21.6%) and Salmonella arizonae (n = 4, 10.8%) - with at least one serotype present in all water sources. Over 60% of Salmonella isolates carried stn gene and the risk was higher in pipe-borne water. There was no relationship (P > 0.05) between enterotoxin-producing gene and antibiotic resistance in Salmonella isolates. Thirteen resistance patterns were exhibited by the isolates, with Str. Amp.Tet.Chl.Amo.Gen, Str. Amp.Tet.Amo.Chl.Amo.Nal.Nit, Str.Tet and Str. Amp.Tet.Chl.Amo being the most notable resistance patterns observed. Isolates that carried stn gene developed resistance to more antibiotics. Although reduced susceptibility to ciproflocacin was observed in two strains, none of the isolates developed resistance to ofloxacin. CONCLUSION: Emerging multidrug-resistant Salmonella serotypes with stn gene were found in the water samples, which may pose a threat to public health. Constant monitoring of pipe leakages, the quality of various wells and the quality of sachet water is advocated to avoid possible future outbreaks of salmonellosis due to consumption of contaminated water.

Isolation and molecular identification of Fusobacterium nucleatum from Nigerian patients with oro-facial infections.

BACKGROUND: Fusobacterium nucleatum is one of the most common anaerobic bacteria present in the oral cavity and is often isolated from infections involving other body sites. OBJECTIVE: To characterise F. nucleatum strains from patients attending a teaching hospital in Nigeria in order to provide information on the methods for accurate identification of anaerobes in clinical specimen. METHODS: Fusobacterium nucleatum specie from 50 patients presenting with oro-facial infections were studied by culture on Fusobacterium selective agar and fastidious anaerobe agar. The isolates were characterised based on colonial morphology, microscopy, lipase production, susceptibility to kanamycin and colistin and resistance to vancomycin. Biochemical tests were performed using a commercial test kit. The identity of the isolates was confirmed based on molecular characterization performed using polymerase chain reaction (PCR) analysis. RESULTS: Forty-eight (96%) F. nucleatum isolates were obtained from the 50 patients by culture and all the isolates were identified by colonial appearance and microscopy based on their unique spindle shape with tapered ends. Only 26 (54.2%) of the 48 isolates were identified by commercial API 20A test kit while PCR confirmed the identity of all the isolates. CONCLUSION: Anaerobes are involved in human infections and their study is quite cumbersome due to tedious nature and high cost of the techniques involved. Cultural method is reliable in the isolation and identification of F. nucleatum species. PCR is a rapid and simple method that can complement the phenotypic identification of anaerobes and would assist in their full identification.

Antibiotic susceptibility patterns in Helicobacter pylori strains from patients with upper gastrointestinal pathology in western Nigeria.

A total of 186 Helicobacter pylori isolates and 532 gastric biopsies recovered from 532 patients with varying degrees of gastroduodenal pathology are subjected to in vitro antibiotic susceptibility testing using the disc-diffusion method, Etest (MIC breakpoints) and molecular testing using the polymerase chain reaction (PCR). In the isolates studied, antibiotic resistance was as follows: piperacillin (72%), amoxicillin (66%), erythromycin (78%), tetracycline (100%) and metronidazole (95%). All isolates were sensitive to ofloxacin, ciprofloxacin and norfloxacin. None of the 245 amplicons (positive for H. pylori) from the biopsies were digested with the Bbs1 and Bsal restriction enzyme used in the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique, showing sensitivity to clarithromycin. However, a 238 bp fragment from H. pylori chromosomal DNA (corresponding to the quinolone resistance determining region [QRDR]) of the gyrA gene was amplified successfully. Twelve (4.9%) of the 245 strains studied had the described mutation at position 91, from asparagine (Asn) to glycine (Gly). The study showed that all the H. pylori strains were sensitive to clarithromycin and ciprofloxacin. It also highlighted PCR as a potential tool for faster diagnosis and determination of antibiotic susceptibility (within 24 h) of H. pylori from biopsies and/or isolates recovered from peptic ulcer and gastritis patients.

Bacteriological and clinical evaluation of twelve cases of post-surgical sepsis of odontogenic tumours at a referral centre.

OBJECTIVE: To determine the bacterial aetiology of sepsis occurring following surgery of odontogenic tumours and assess the effect of prompt and proper antibiotic usage. DESIGN: A prospective study. SETTING: A tertiary referral centre in Lagos, Nigeria. SUBJECTS: Twelve patients with odontogenic tumours that developed sepsis postoperatively. Eight of the patients were referred from private hospitals, the remaining were in-patients who sought for alternative medical attention following interruption of health care services at the referral centre. INTERVENTION: Adequate review of patient's medical history, bacteriological investigations and antibiotic therapy. MAIN OUTCOME MEASURES: Bacteriological and clinical cure following antibiotic therapy based on susceptibility test results. RESULTS: Two categories of patients were identified; those who completed the course of antibiotics prescribed post-surgery and patients who failed to conform to antibiotic prescription. Sepsis developed in the non-compliance group much earlier than in the group that complied (p<0.001). Infections were polybacterial with aerobes accounting for 77.4% (alpha-haemolytic streptococci 29.0%, Streptococcus pyogenes 16.1%, Staphylococcus aureus 16.1%, diphtheroids 9.7%, Klebsiella pneumoniae 6.5%) and anaerobes 22.6% (Porphyromonas gingivalis 9.7%, Peptostreptococcus spp. 6.5%, Prevotella melaninogenica 3.2%, Clostridium perfringens 3.2%). Mixed aerobic and anaerobic aetiology occurred more in osteosarcoma and fibrosarcoma. Clostridium perfringens was isolated from a case of osteosarcoma with necrotic tissues. The anaerobic bacteria were 100% sensitive to metronidazole, ciprofloxacin and augmentin, 65-85% sensitivity to ampicloxacillin, amoxicillin and erythromycin. Over 92% of the streptococci were sensitive to the beta-Lactams contrast low susceptibility with S. aureus and K. pneumoniae. CONCLUSION: Interruption of healthcare service was the sole factor identified in the development of sepsis as the patients could not be monitored to ensure compliance to prescription.

Susceptibility of cariogenic Streptococcus mutans to extracts of Garcinia kola, Hibiscus sabdariffa, and Solanum americanum.

BACKGROUND: The elimination of cariogenic bacteria from the oral cavity using antibacterial agents is one of the primary strategies for the prevention of dental caries. Avariety of plants with potent activity are known to be used in indigenous communities for dental hygiene worldwide. OBJECTIVE: To determine if Hibiscus sabdariffa, Solanum americanum and Garcinia kola can inhibit the growth of cariogenic bacteria in the mouth. METHODS: Methanol and aqueous extracts obtained from three plants, Hibiscus sabdariffa, Solanum americanum and Garcinia kola were studied for their antibacterial activity against cariogenic Streptococcus mutans obtained from patients with clinically identified carious lesions, using the agar dilution method. The sources of extracts for Garcinia, Hibiscus and Solanum were respectively fruits and leaves for the latter two. RESULTS: The extracts (both methanol and aqueous) from Garcinia kola showed the most intensive activity and completely inhibited the growth of the primary cariogenic Streptococcus mutans at 1.25 mg/ml. Hibiscus sabdariffa was also active at a minimum inhibitory concentration (MIC) of 2.5mg/ml while Solanum americanum did not show any direct effect on S. mutans. CONCLUSION: The result of this study showed that G. kola and H. sabdariffa have direct antibacterial effect on Streptococcus mutans.

Campylobacter enteritis in Ilorin, Nigeria.

BACKGROUND: Campylobacterje junilcoli is one of the most commonly identified bacterial causes of acute gastroenteritis worldwide. In Nigeria, it has been reported in the northern part of the country, extensive work has also been done in the south-west leaving behind the middle-belt of the country. OBJECTIVE: To determine the role of Campylobacter jejunilcoli as an agent of diarrhoea in the middle-belt of Nigeria. DESIGN: A prospective case control study. SETTING: University of Ilorin Teaching Hospital (UITH), private hospitals and primary health centers all in Ilorin, Nigeria. SUBJECTS: Three hundred and six children with diarrhoea and 100 without diarrhoea were randomly selected. MAIN OUTCOME MEASURES: Isolation of Campylobacter jejuni/coli from stool samples. Biological characteristics of the isolates. RESULTS: Twenty five (8.2%) of the patients and none of the controls had the organism. Campylobacter jejuni and C. coli were 56% and 44% respectively. All the isolates were susceptible to erythromycin and ciprofloxacin. None of the isolates harboured plasmids. CONCLUSION: C. jejunil coli is an important diarrhoea agent in our geographic environment, further characterisation is desired of these local strains.

Prevalence of EHEC O157:H7 in patients with diarrhoea in Lagos, Nigeria.

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.

Serotypes among Lancefield-group G streptococci isolated in 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.

A 12-month surveillance of 'flu-like infections in a sample from the population of Lagos.

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.

Urban yellow fever epidemic in western Nigeria, 1987.

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.

Zoonotic infections in Nigeria: overview from a medical perspective.

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.

Acute normovolaemic haemodilution in colorectal surgery.

AIMS: Blood transfusions are often given to surgical patients. This study was designed to assess whether acute normovolaemic haemodilution (ANH) reduces exposure to allogeneic blood, affects clinical outcome and hospital stay, and is feasible in colorectal surgery. METHODS: All ASA 1 and 11 patients undergoing colectomies performed between 1997 and 1999 were identified retrospectively from our colorectal cancer database to ascertain our current peri and postoperative transfusion practice. Twenty-six selected patients subsequently underwent ANH during colectomy surgery. The number of patients and units transfused were identified. RESULTS: One hundred and twenty-three of 317 (39%) patients identified from our colorectal cancer database were transfused a total of 328 units (median 2, range 1-7). Of the 26 patients undergoing ANH, 4 (15%) were transfused a total of 13 units (median 3, range 2-5). The reduction in number of patients transfused was statistically significant (P=0.017). ANH increased anaesthetic time by a median of 19 min. There were no complications associated with ANH and the median hospital stay was 9 days (range 6-13). CONCLUSIONS: In this pilot study of selected patients, ANH is a feasible and effective method of reducing allogeneic blood exposure in major colorectal surgery. A prospective randomised controlled trial is now urgently required.

The anaerobic and aerobic bacterial flora of leg ulcers in patients with sickle-cell disease.

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.

Comparison of three PCR methods for detection of Helicobacter pylori DNA and detection of cagA gene in gastric biopsy specimens.

AIM: To comparatively evaluate PCR and other diagnostic methods (the rapid urease test and / or culture) in order to determine which of the three PCR methods (ureA, glmM and 26-kDa, SSA gene) was most appropriate in the diagnosis of Helicobacter pylori (H pylori ) infection and also to evaluate the detection of a putative virulence marker of H pylori, the cagA gene, by PCR in biopsy specimens. METHODS: One hundred and eighty-nine biopsy specimens were collected from 63 patients (three biopsies each) undergoing upper gastroduodenal endoscopy for various dyspeptic symptoms. The PCR methods used to detect H pylori DNA directly from biopsies were the glmM, 26-kDa, ureA and then cagA was used to compare the culture technique and CLO for urease with the culture technique being used as the gold standard. RESULTS: Thirty-five percent of the biopsies were positive for H pylori DNA using the 3 PCR methods, while 68% of these were positive for the cagA gene. Twenty-four percent of the biopsies were negative for H pylori DNA in all PCR methods screened. The remaining 41% were either positive for ureA gene only, glmM only, 26-kDa only, or ureA + glmM, ureA + 26-kDa, glmM + 26-kDa. Out of the 35% positive biopsies, 41% and 82% were positive by culture and CLO respectively, while all negative biopsies were also negative by culture and cagA. Cag A+ infection was also predominantly found in H pylori DNA of the biopsies irrespective of the clinical diagnosis. CONCLUSION: This method is useful for correctly identifying infections caused by H pylori and can be easily applied in our laboratory for diagnostic purposes.

Antibiotic susceptibility of clinical isolates of Prevotella bivia in Lagos, Nigeria.

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.

Deoxyribonucleic acid restriction digest patterns in Campylobacter species: a comparison with Penner serotype.

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.

Antibiotic susceptibility patterns and beta-lactamase production of animal and human isolates of Campylobacter in Lagos, Nigeria.

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.