Akitoye O. Coker

Human Campylobacteriosis in Developing Countries1

Campylobacteriosis is a collective description for infectious diseases caused by members of the bacterial genus Campylobacter. The only form of campylobacteriosis of major public health importance is Campylobacter enteritis due to C. jejuni and C. coli. Research and control efforts on the disease have been conducted more often in developed countries than developing countries. However, because of the increasing incidence, expanding spectrum of infections, potential of HIV-related deaths due to Campylobacter, and the availability of the complete genome sequence of C. jejuni NCTC 11168, interest in campylobacteriosis research and control in developing countries is growing. We present the distinguishing epidemiologic and clinical features of Campylobacter enteritis in developing countries relative to developed countries. National surveillance programs and international collaborations are needed to address the substantial gaps in the knowledge about the epidemiology of campylobacteriosis in developing countries.

Screening of Some Medicinal Plants Used in South-West Nigerian Traditional Medicine for Anti-Salmonella typhi Activity

Ten Nigerian medicinal plants used traditionally for the treatment of several ailments of both microbial and non-microbial origins were tested on multi-drug resistant S. typhi(MDR) strains of which six of them were active. The results revealed that both the aqueous and ethanol extracts of Terminalia avicennioides, Momordica balsamina, Combretum paniculatumand Trema guineensiswere effective on the MDR-S. typhistrains with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging from 9.60 to 14 mcg/ml and 24 to 33 mcg/ml, respectively. Whereas, only the aqueous extracts of Morinda lucidaand Ocimum gratissimumwere found to be active against this pathogen with MIC and MBC values of 9.60 and 24 mcg/ml for M. lucida, 40 and 55 mcg/ml for O. gratissimum, respectively. There was no statistical significant difference (P > 0.05) between the activity of each plant extract and the decoctions prepared from them. All the six active plants showed positive reactions to alkaloids, tannins, flavonoids and anthraquinones but in variable degrees. All but M. balsamina, indicated the presence of saponin.

Associated risk factors and pulsed field gel electrophoresis of nasal isolates of Staphylococcus aureus from medical students in a tertiary hospital in Lagos, Nigeria

Staphylococcus aureus infections are growing problems worldwide with important implications in hospitals. The organism is normally present in the nasal vestibule of about 35% of apparently healthy individuals and its carriage varies between different ethnic and age groups. Staphylococcal nasal carriage among health workers is particularly important to establish new clones and track origin of infections during outbreak situations. To determine the carriage rate and compare the pulsed field gel patterns of the strains, nasal swabs were collected from 185 medical students in a teaching hospital in Lagos, Nigeria. Isolates of S. aureus were tested for heamolysin production, methicillin sensitivity and Pulsed Field Gel Electrophoresis (PFGE) was performed. The results showed S.aureus nasal carrier rate of 14% with significant rate among males compared to females. All the isolates produced heamolysin. Antibiotic susceptibility pattern revealed that majority of the isolates was susceptible. Five strains (19%) harboured resistant determinants to penicillin and tetracycline. None of the strains was resistant to methicillin. 44% of the isolates typed by PFGE had type B, the most predominant pulsotype. PFGE A clone exhibited a single resistance phenotype suggesting a strong clonal relationship that could punctual an outbreak in the hospital. The results speculate that nasal carriage among medical personnel could be a function of various risk factors. Personal hygiene and behaviour may however be the means to reducing colonization and spread of S.aureus in our hospitals.

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.

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.

High amoxycillin resistance in Helicobacter pylori isolated from gastritis and peptic ulcer patients in western Nigeria.

omeprazole or bismuth for 2 weeks. Treatment failure has been reported in some patients, and in others there is usually the attendant problem of the patients not coming back to the clinic, most because of the cost and the lack of free health care in Nigeria. There is no documented eradication rate of H. pylori in Nigeria. The main problem is lack of ability to isolate the organism in most laboratories, as a result of the specialized conditions required for isolation. Therefore, the few patients who have follow-up endoscopy are usually checked on the basis of the CLO test and, occasionally, histology. There have been few documented cases of H. pylori from the north of the country and the majority of biopsy samples were not cultured,2,3 although our study (from the western region) has documented work on the CLO test, culture, and gram staining.4 In northern Nigeria, Holcombe et al.2,3 reported the prevalence of H. pylori by histology to be 87%, with culture (62% and 72.7% respectively) being positive for H. pylori. From our culture study of H. pylori, 27% of patients with gastritis and peptic ulcer in western Nigeria were positive.4 One of the reasons for the high metronidazole resistance in this part of the world is that medical practitioners, especially those in private practice, prescribe metronidazole; metronidazole for the treatment of parasitic infections and urinary tract infections (UTI). Ampicillin is a drug that is widely abused in this part of the world; it is generally sold in the streets (especially the 250-mg and 500-mg doses). Amoxycillin is also sold in the streets. The possibility of bacterial strains acquiring resistance to amoxycillin and ampicillin is strong, because both are penicillins and â-lactamase agents. Colonization of the stomach with ampicillin and, possibly, other â-lactam-resistant bacteria may also lead to the transfer of amoxicillin resistance to H. pylori. To determine resistance to antibiotics, the disk diffusion technique is cheap and reliable for use, especially in developing countries where the E test and determining the minimum inhibitory concentration Helicobacter pylori has been proposed as the etiologic agent of gastric and duodenal ulcers, antral gastritis, and some gastric carcinoma.1 It has been noted that the eradication of H. pylori leads to the permanent cure of peptic ulcer disease.1 In Nigeria, most often, blind therapy, or what is referred to as empirical treatment, is given to patients who have endoscopic symptoms of ulcer or gastritis and are Campylobacter like organisms (CLO) positive, and, to a lesser extent, show histological gastritis. The study therefore aimed at carrying out in-vitro antibiotic susceptibility testing on the H. pylori strains isolated from patients presenting with peptic ulcer and gastritis in Nigeria, in particular using the antibiotics commonly prescribed for these patients to prove their efficacy and or to explain the reasons for observed treatment failures. All the isolates were resistant to amoxycillin, ampicillin, piperacillin, erythromycin, tetracycline, and metronidazole. All the strains had zone sizes of 7.6mm or less with these agents. The majority (75%) of the isolates were resistant to cefuroxime. All were sensitive to ofloxacin, ciprofloxacin, and norfloxacin. All were moderately sensitive to imipenem. Twenty-five percent of the strains were sensitive to gentamicin and kanamycin (Table 1). No â-lactamase activity was detected in any of the H. pylori strains. This study showed that all the H. pylori isolated from western Nigeria were resistant to ampicllin, amoxycillin, tetracycline, and metronidazole. Unfortunately, two of these drugs (metronidazole and amoxycillin) form the crux of the drugs used for the treatment of H. pylori infections in Nigeria. In Nigeria, as a result of the high rate of drug abuse, clinicians give the following drug combinations: 1 g amoxycillin three times daily for 2 weeks; 400 mg metronidazole daily for 10 days, and

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

Abstract 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 Bsa1 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.

Fingerprinting of Nigerian Helicobacter pylori isolates by plasmid profile and PCR

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 >10kb. 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.

Diagnosis of Helicobacter pylori infection among patients with dental caries by stool antigen test.

Detection of parvovirus B19 IgG: choice of antigens and serological tests. J Clin Virol 2004; 29: 51–3. 9 Landini MP, Re MC, Mirolo G, Baldassarri B, La Placa M. Human immune response to cytomegalovirus structural polypeptides studied by immunoblotting. J Med Virol 1985; 17: 303–11. 10 Engstrom SM, Shoop E, Johnson RC. Immunoblot interpretation criteria for serodiagnosis of early Lyme disease. J Clin Microbiol 1995; 33(2): 419–27.

Information technology literacy among Nigerian microbiology students and professionals

Education and research in the discipline of microbiology is set for change as a result of computers being used as teaching and learning tools. In order to catalyse this change in Nigeria, previous computer experience, knowledge and attitude to computers of Nigerian microbiology students and professionals was determined. Our results indicate the need to increase the awareness of use and potentials of computers in microbiological research and education.