Molecular typing and antibiotic susceptibility patterns of enteropathogenic and shigatoxin producing Escherichia coli isolated from food handlers in three areas of Kenya.

OBJECTIVES: To determine the aetiology, epidemiology and sanitary factors of carriage of enteropathogenic Escherichia coli (EPEC) and Shiga-toxin producing E. coli (STEC) in food-handlers working in tourist hotels in three popular tourist destinations in Kenya. DESIGN: Cross sectional laboratory based study. SETTING: Three tourist destinations of Nairobi, Malindi and Diani in Kenya. SUBJECTS: Food handlers who were working in hotels frequented by tourists in the three study sites. RESULTS: Overall, during the period of April 2003 to May 2004, a total of 1399 food handlers stool samples were collected and analysed. EPEC expressing the eaeA gene and STEC expressing the stx2 gene were detected in 11/1399 (0.8%) and 2/1399 (0.1%) of the study subjects respectively. The mean age of the subjects from whom EPEC and STEC were isolated was similar (32.6 years) to those from whom no EPEC and STEC were isolated (32.5 years). Prior use of antibiotics, water source and toilet types were not significantly associated with the isolation of EPEC and STEC (p>0.05). There were 11 resistance patterns with six isolates (6/13, 46.2%) showing multidrug resistance. High prevalence of resistance was observed to co-trimoxazole (55.6%), chloramphenicol (33.3%), ampicillin (22.2%) and tetracycline (22.2%). High concentrations of antibiotics were required to achieve MIC90 for tetracycline, (>64 mg ml(-1)) and ampicillin (>256 mg ml(-1)). Cluster analysis of the Pulse Field Gel Electrophoresis profiles revealed that the EPEC and STEC isolates belonged to two main genotypes with 11 distinct DNA fragment profiles. CONCLUSION: This is the first report in Africa on the isolation of STEC from food handlers working in tourist hotels. These food handlers who carry the STEC and EPEC could potentially infect tourists and other people through food or water contamination in the hotel settings and thus our findings are of great public health importance.

Molecular technique utilising sputum for detecting Wuchereria bancrofti infections in Malindi, Kenya.

BACKGROUND: Lymphatic filariasis is a tropical parasitic disease which has been identified for elimination by 2020 through mass drugs administration. There is a major problem in its diagnosis and sensitive surveillance methods for monitoring the disease elimination programs need to be sought. OBJECTIVES: To establish and evaluate the usefulness of a Polymerase Chain Reaction, PCR assay employing sputum for diagnosis of Wuchereria bancrofti infections in an endemic location. DESIGN: Community based samples collection and a molecular laboratory technologies study. SETTING: Mpirani, Malindi District and Centre for Biotechnology Research and Development, Kenya Medical Research Institute. SUBJECTS: Sputum samples were obtained from 304 willing and consenting participants, aged between 5 and 73 years resident in Mpirani, Malindi District. RESULTS: Prevalence of W. bancrofti infection was found to be 42.8% (130/304) by PCR assay employing sputum compared with 22.0% (67/304) and 38.8% (119/304) respectively for microfilaria counts and ICT. The sensitivity and specificity of the PCR sputum assay was 97.5 and 92.4% respectively. Predictive values were 89.2 and 98.3% for positive (PPV) and negative (NPV) respectively while accuracy was 94.4%. CONCLUSIONS: The molecular PCR assay using sputum was found to have a great potential for use in mass diagnosis and in epidemiological studies in patients with W. bancrofti infections

Non-typhi salmonella in children with severe malaria.

OBJECTIVE: To determine the association between Plasmodium falciparum malaria and non-typhi Salmonella in children. DESIGN: Cross-sectional hospital based study. SETTING: Kilifi District Hospital (KDH) between January 1997 and June 2001. SUBJECTS: Children aged between three months to 123 months (mean age 28.28 months) and who had been admitted to the paediatric or High Dependency Research Ward (HDRW) of the KDH. METHODS: A total of 19, 118 blood cultures routinely obtained for all admissions and 1,820 clinically indicated stools samples were obtained from 9,147 children admitted with malaria. The specimens were cultured and antibiotic sensitivity done using standard laboratory procedures with stringent internal and external quality control in place. RESULTS: The total bacterial pathogens isolated from blood and stool were 1,395/19,118 (7.3%) and 342/1,820 (19%) respectively. Non-typhi salmonella consisted of 260/1,395 (18.6%) of the positive blood cultures and 92/324 (28.4%) of the stool cultures out of which a total of 101 NTS occurred in children with severe malaria. Out of the 9,147 malaria cases admitted, 101/9,147 (1.10%) had concomitant NTS infection. NTS with severe malaria as a proportion of all malaria admissions for the period varied between 0.8% and 1.5%. There was a significant association (p-value=0.032) between clinical outcome of death and female sex of the patient. The NTS isolates which occurred with severe malaria showed various levels of antibiotic resistance. They were resistant to ampicillin (35%), chloramphenicol (18%), gentamicin (22%), cefuroxime (29%), sulphamethoxazole-trimethoprim (39%), ciprofloxacin (3%), cefotaxime (14%), amoxycillin-clavulanic acid (26%) and tobramycin (18.0%). Multidrug resistance (MDR) was seen in 34 (33.6%) of the isolates. CONCLUSIONS: NTS and severe malaria occurring together are a problem in this area and that a large number of the isolates are MDR. An elaborate case-controlled study is required to elucidate the chain of events of both NTS and malaria parasite co-existence.

Electron microscopy studies on Gardnerella vaginalis grown in conventional and biofilm systems.

The cell-wall characteristics of Gardnerella vaginalis grown in conventional and biofilm systems were studied by electron microscopy. The gram-positive nature of the cell wall was confirmed. Novel cell-wall particles which appeared to be associated with cell division were also identified, particularly in organisms of biofilm origin.

Use of a continuous-culture biofilm system to study the antimicrobial susceptibilities of Gardnerella vaginalis and Lactobacillus acidophilus.

Gardnerella vaginalis and Lactobacillus acidophilus have been shown to grow to high titers in a simple biofilm system. This system was used in the present investigation to compare the biofilm-eradicating concentrations (BECs) of amoxicillin, clindamycin, erythromycin, and metronidazole to standard tube MIC and minimum bactericidal concentration (MBC) results. With the lactobacillus, the BEC/tube MBC ratio was at least 16:1, while for G. vaginalis the ratio varied from 2:1 to 512:1. The simple continuous-culture system used in the present investigation is ideal for investigating the BEC for bacteria involved in complex ecological situations such as bacterial vaginosis and may be useful for the identification of the most effective and selective antibiotic therapy.

The growth of Gardnerella vaginalis and Lactobacillus acidophilus in Sorbarod biofilms.

Sorbarod biofilms were investigated for their suitability in establishing continuous culture biofilms for the study of bacterial vaginosis. Two important organisms in the condition, Gardnerella vaginalis and Lactobacillus acidophilus, were studied. In contrast to growth in broth culture, both organisms were maintained for at least 96 h in a steady state on the biofilms. With G. vaginalis, the haemolytic activity was consistently maintained in the biofilms in contrast to short-term activity in broth culture which matched the bacterial titre. The simple Sorbarod system appears to be suitable for studying the growth conditions of bacteria in continuous culture and has potential for investigating interactions between micro-organisms.

Perception of risk, sexual behaviour and STD/HIV prevalence in western Kenya.

OBJECTIVE: To determine the feasibility and acceptability of collecting data on sexual practices, knowledge, attitudes and perception of risk with regard to HIV and STD infection in two clinic populations. DESIGN: A cross sectional survey carried out between June and July 1992. SETTING: An urban and a rural health centre in western Kenya. SUBJECTS: One hundred and sixty women attending Maternal Child Health (MCH) and Family Planning Clinics (FP). INTERVENTIONS: Screening STDs including N. gonorrhoea, C. trachomatis, T. vaginalis and syphilis. In addition subjects were interviewed about sexual practices, knowledge, attitudes and perception of risk with regard to HIV and STD infection. RESULTS: The presence of any STD including HIV was detected in 36.2% of women at the urban clinic and 21.2% of women at the rural clinic. The demographics of the two populations were similar with respect to age but were significantly different for several variables including marital status, ethnicity and education. Knowledge of STDs and HIV was nearly universal in both clinic populations with > 96% of patients being aware of the existence of such diseases. 76.3% of women at the urban clinic felt they could get an STD as compared to 48.8% at the rural clinic (p < 0.02). This awareness of vulnerability among the urban population was also seen for HIV. CONCLUSION: It appears to be feasible to conduct studies of sexual practices and perceptions of risk for STD/HIV acquisition in women attending health centres in Kenya.