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Biomedical subjects

P G Waiyaki

Publications and source records attributed to P G Waiyaki.

At least 19 recordsLinked to original sources
PubMed2005

Detection of Mycoplasma genitalium in women with laparoscopically diagnosed acute salpingitis.

OBJECTIVES: Mycoplasma genitalium has been associated with cervicitis, endometritis, and tubal factor infertility. Because the ability of this bacterium to ascend and infect the fallopian tube remains undefined, we performed an investigation to determine the prevalence of M genitalium in fallopian tube, endometrial, and cervical specimens from women laparoscopically diagnosed with acute salpingitis in Nairobi, Kenya. METHODS: Women presenting with pelvic inflammatory disease were laparoscopically diagnosed with salpingitis. Infection with M genitalium in genital specimens was determined by polymerase chain reaction (PCR). RESULTS: Of 123 subjects with acute salpingitis, M genitalium was detected by PCR in the cervix and/or endometrium in nine (7%) participants, and in a single fallopian tube specimen. In addition, those infected with M genitalium were more often HIV infected than women not infected by M genitalium (seven of nine (78%) v 42 of 114 (37%), p<0.03). CONCLUSIONS: M genitalium is able to ascend into the fallopian tube, but its association with tubal pathology requires further investigation.

Acute Disease↗
PubMed2002

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.

Age Distribution↗
PubMed1998

Chronic diarrhoea among HIV-infected adult patients in Nairobi, Kenya.

OBJECTIVES: Chronic diarrhoea and wasting are well recognized features of AIDS in Africa. However, because of resource constraints few comprehensive aetiological studies have been conducted in sub-Saharan Africa which have included a broad range of microbiological investigations. We undertook a prospective cross-sectional study of adult patients admitted to a government hospital in Nairobi, Kenya, to determine possible bacterial, mycobacterial, parasitic and viral causes of diarrhoea; to consider which may be treatable; and to relate microbiological findings to clinical outcome. METHODS: Stool specimens from 75 consecutive HIV-seropositive patients with chronic diarrhoea admitted to a Nairobi hospital were subjected to microbiological investigation and results were compared with clinical findings and outcome. Stool samples were cultured for bacteria and mycobacteria and underwent light and electron microscopy; lawns of Escherichia coli were probed for pathogenic types and aliquots were tested for the presence of Clostridium difficile cytotoxin. Blood cultures for mycobacteria and other bacterial pathogens were performed as clinically indicated. RESULTS: Thirty-nine (52%) patients yielded putative pathogens, the most common being Cryptosporidium sp. (17%), Salmonella typhimurium (13%), and Mycobacterium tuberculosis (13%). Of 41 patients investigated for pathogenic Escherichia coli, enteroaggregative E. coli and diffusely adherent E. coli were each found in four patients. Thirty-one (41%) patients died. Detection of cryptosporidium cysts was the single most significant predictor of death (X2 = 5.2, P<0.05). Many patients did not improve (21; 28%) or self-discharged whilst still sick (5; 7%) but five (7%) were diagnosed ante mortem with tuberculosis and treated and a further 13 (17%) showed improvement by time of discharge. CONCLUSIONS: HIV-infected patients with chronic diarrhoea in Nairobi have a poor outcome overall, and even with extensive investigation a putative pathogen was identified in only just over half the patients. The most important step is to exclude tuberculosis; and the most useful investigation appears to be Ziehl-Neelsen staining. Other potentially treatable gram-negative bacterial pathogens, S. typhimurium, Shigella sp. and adherent E. coli were, however, common but require culture facilities which are not widely accessible for definitive identification. Further studies focussing on simple ways to identify sub-groups of patients with treatable infections are warranted.

Adolescent↗
PubMed1997

Epidemiological study on infectious diarrheal diseases in children in a coastal rural area of Kenya.

Diarrheal diseases are major causes of morbidity and mortality among children in developing countries. We have analyzed the causative agents of diarrhea in children under five years of age who resided in rural environments but attended a hospital in Malindi, a coastal town in Kenya. Bacterial diarrhea was found in 239 (27.7%) of 862 patients with diarrhea. Diarrheagenic Escherichia coli, including enteropathogenic, enterotoxigenic, and enterohaemorrhagic strains, was isolated from 119 (13.8%) patients, followed by Salmonella spp. (63 cases, 7.3%) and Shigella spp. (56 cases, 6.5%). Intestinal parasites were found in 109 (12.6%) of the patients. Entamoeba histolytica and Giardia lamblia were found in 67 (7.8%) and 42 (4.9%) of the cases, respectively. Rotavirus was found in 69 (16.1%) of 428 cases, a part of the 862 cases. Significant differences in age distribution were seen in diarrheal cases due to Campylobacter spp., G. lamblia, and rotavirus. No significant seasonal incidence of specific pathogens was found, but the number of diarrheal patients was significantly correlated to rainfall. Drinking water was contaminated with bacteria at concentrations ranging from 10(3) to 10(6) CFU/ml in 98% of the households and by coliform bacteria at concentrations of 10(2) to 10(5) CFU/ml in 72% of the households. These results suggest that the main routes of infection may be contaminated drinking water and fecal-oral transmission of enteric pathogens. Consequently, we propose that the enhancement of hygienic practice through health education is a feasible control measure of diarrhea in the study area.

Age Distribution↗
PubMed1997

Effect of piped water supply on human water contact patterns in a Schistosoma haematobium-endemic area in Coast Province, Kenya.

The effect of a piped water supply on human water contact in a Schistosoma haematobium-endemic area in Coast Province, Kenya was studied. After the construction of five community standpipes and one shower unit, there was a 35.1% reduction in the number of people observed using river water, a 44.1% reduction in the frequency of contact with river water, and a 25.4% reduction in the amount of contact. The frequency of river water contact per person also decreased significantly, but the amount of contact per person did not decrease. The total frequency of contact decreased significantly except for washing clothes by the river, washing utensils, and fishing. The frequency per person did not change for most of the activities and significantly increased for washing clothes. The frequency of river water contact in households with high piped water consumption showed a significant decrease compared with those with low piped water consumption. The volume of consumption of piped water was inversely proportional to the distance from the home to the community standpipe. These results indicate that in the study area, the effect of a piped water supply on river water contact behavior was heterologous while the total river water contact decreased significantly, and that the piped water had a beneficial effect on some villagers but very little effect on others.

Adolescent↗
PubMed1996

Cholera: its story in Africa with special reference to Kenya and other east African countries.

Cholera is an acute often fatal infection whose aetiology, epidemiology, clinical presentation, management, prevention and control are well understood. However, the disease has recently re-emerged as a serious microbial threat due to environmental pressures, increased international travel, population migrations and the emergence of new strains of "old" pathogens. This paper emphasizes, the significance of putting into place quick surveillance methods backed by laboratory services and the importance of creating a rapid response capacity and mechanics to outbreaks.

Africa, Eastern↗
PubMed1995

Epidemiology of HIV infection among long distance truck drivers in Kenya.

A total number of two hundred eighty three long distance truck drivers and their assistants (loaders) who ferry goods between Kenya and Zaire were included in a cross-sectional study between September 1991 and April 1992. Twenty six percent of the study subjects were seropositive for HIV-1 and none were HIV-2 seropositive. Countries of birth and residence were significantly associated with HIV infection (X2 = 23.6, P = 0.0006). Significant associations were also found between HIV seropositivity and level of education from secondary school and above (OR = 3.4, 95% C.I. = 1.01-11.55); being circumcised was more protective, (OR = 0.38; 95% C.I. = 0.19-0.76), history of many years of driving (X2 = 9.3, p = 0.0254) and income (OR = 11.13, 95% C.I. = 1.35-91.95). When a stepwise multiple logistic regression model was fitted to all the variables observed to be significant in the univariate analysis, the following risk factors attained statistical significance: lack of circumcision (OR = 3.75); income greater than Ksh. 2000 (OR = 7.24); being employed in long distance driving more than 11 years (OR = 3.98); and secondary school education and above (OR = 4.06, 95% C.I. = 1.18-13.98). Reference for all the above Odds Ratios was 1.

Adult↗
PubMed1995

Bacteriology and sensitivity patterns of pyogenic meningitis at Kenyatta National Hospital, Nairobi, Kenya.

A descriptive cross sectional study on bacteriology and sensitivity patterns of laboratory-proven pyogenic meningitis was carried out over a six month period. A total of 92 patients (52 adults, 40 children) were studied. In 75 (82%) of the cases, the cerebrospinal fluid cultures were bacteriologically positive. Common isolates included Streptococcus pneumoniae (45%), Neisseria meningitidis (14%) and Haemophilus influenzae (12%). Other isolates included Cryptococcus neoformans from four (4.3%) adults who were also HIV-l positive. Sensitivity to antibiotics was determined using the disk diffusion method. There was no resistance to chloramphenicol among the three most common bacterial isolates. However, 7% and 15% of Streptococcus pneumoniae and N. meningitidis isolates, respectively, were resistant to crystalline penicillin. Twenty seven percent of Haemophilus influenzae was resistant to ampicillin. Sensitivity of the three organisms to the third generation cephalosporin (ceftazidime, cefotaxime, ceftriaxone) a second generation cephalosporin (cefuroxime) and augmentin was almost 100%. We recommend that chloramphenicol and crystalline penicillin or ampicillin be initial blind therapy for adults and older children with pyogenic meningitis and ampicillin and chloramphenicol for pre-school children. The above cephalosporins and augmentin are alternative therapy but their use will be limited by cost.

AIDS-Related Opportunistic Infections↗
PubMed1993

Ecological study on the intestinal bacteria flora of patients with diarrhea.

In the intestinal flora of patients with diarrhea, a close correlation exists between a decrease in numbers of anaerobes and a reduction in levels of short-chain fatty acids. The drastic reduction of intestinal volatile fatty acids (VFAs) accompanying decreased counts of anaerobes during the diarrheal state and the increase in pH thought to arise from these changes result in increased fecal water content. Our data suggest that free bile acids and VFAs may be factors controlling intestinal bacterial populations in vivo, especially in enteric infections. Thus the role of nonspecific factors such as VFAs, which are among the bile acid metabolites produced by anaerobic intestinal bacteria, deserves emphasis in the evaluation of protective mechanisms provided by the intestinal flora against enteric infections.

Adolescent↗
PubMed1993

Infection and morbidity in patients with tuberculosis in Nairobi, Kenya.

OBJECTIVE: To examine the role of acute infection as a cause of morbidity in patients with tuberculosis. DESIGN: Cross-sectional documentation of predefined acute morbid events. SETTING: Infectious Diseases Hospital, Nairobi, Kenya. PATIENTS: Adults (> or = 15 years), inpatients and outpatients with a diagnosis of tuberculosis presenting with one or more of a series of clinical features. A new event was defined as one occurring at least 1 week after the initial event. INTERVENTIONS: Patients' treatment was modified depending on the results of laboratory investigations. MAIN OUTCOME MEASURES: There were 642 events from 398 patients, 235 HIV-positive patients had 438 events and 163 HIV-negative patients had 204 events (P < 0.0001). Forty-two out of the 235 (18%) HIV-positive patients were bacteraemic compared with nine out of the 163 (6%) HIV-negative patients (P = 0.0003). The most common isolates from blood were Salmonella typhimurium and Streptococcus pneumoniae. RESULTS: Faecal specimens were obtained more commonly from HIV-positive patients (P < 0.001), and often contained bacterial pathogens. CONCLUSIONS: Many of the causes of morbidity in patients with tuberculosis and HIV are not due to tuberculosis or antituberculous therapy, and will not be identified without microbiological investigation.

Adolescent↗
PubMed1993

Anti-tuberculous initial drug resistance of Mycobacterium tuberculosis in Kenya: a ten-year review.

Our experience at the Respiratory Diseases Research Unit (RDRU), over the last 10 years (1981-1990) on the initial drug resistance pattern, focusing on three drugs viz: isoniazid (H), streptomycin (S) and rifampicin (R) is presented. Records on all isolates of M. tuberculosis from one specimen of every newly diagnosed patient recruited countrywide between 1981-1990 were reviewed. We analyzed records of 6,514 isolates and found that total resistance to the three drugs had increased from 8.9% to 14.4%. Resistance to H alone increased from 6.8% to 10.2% while that of S alone from 0.8% to 1.8%. Resistance to R was between 0.1% and 0.3%. Generally, the increase in the resistance trend to both H and S was statistically significant (p = < 0.05 and 0.03, respectively). Although in our analysis we did not address the possible impact of HIV infection, we hope that these findings form a basis for evaluation of this and other possible factors on the emergence of anti-TB drug resistance in future studies.

Drug Resistance, Microbial↗
PubMed1992

The fimbriae-like structures on V. cholerae isolated in Kenya.

For Vibrio cholerae 01 to overcome the normal intestinal clearing mechanisms and facilitate colonization in the host gut, fine filamentous structures covering the surface of all the cell must exist. These fimbriae-like structures were investigated in this study. Selection of the K23 V. cholerae 01 biotype el-tor isolated in Kisumu, Kenya, was based on its proteinase activity and ability to agglutinate 0.2M ammonium sulphate. This strain was cultured in modified tryptone broth pH 8.4, at 37 degrees C overnight. Electron microscopy of the strain revealed the presence of fimbriae-like structures which varied in number. Some cells showed more than 200, whereas in other cells only several filamentous structures were detected. It is suggested that these structures could be a possible candidate for a cholera vaccine.

Evaluation Studies as Topic↗
PubMed1992

The presentation and outcome of HIV-related disease in Nairobi.

The range of clinical presentations of HIV-related disease in Africa has not been adequately described, despite the fact that many hospitals have to rely heavily on clinical diagnosis. Six hundred adult medical patients seen in the Casualty Department of the main Government hospital in Nairobi were enrolled in a study of the presentation and outcome of HIV-related disease: 506 of these patients were admitted, of whom 19 per cent (95) were HIV seropositive. The remaining 94 were dealt with as outpatients: 11 percent (10) of these were seropositive. A history of prior treatment for sexually transmitted disease and, if male, being uncircumcised, were associated with being seropositive. Three presentations were strongly associated with HIV infection: acute fever with no focus except the gastrointestinal tract (enteric fever-like illness), acute cough with fever (community-acquired pneumonia) and chronic diarrhoea with wasting. The WHO clinical case definition (CCD) for AIDS missed a substantial amount of HIV-related morbidity (sensitivity 39 per cent) and misidentified many seronegative patients (positive predictive value 59 per cent). In comparison with the Centers for Disease Control surveillance definition for AIDS, the CCD was specific (91 per cent) and sensitive (79 per cent) but only had a positive predictive values of 30 per cent: the CCD may therefore be a poor surveillance tool for AIDS. Seropositive patients were much more likely to die than were seronegative patients (39 per cent vs. 15 per cent mortality). Enteric fever-like illness was the presentation which most commonly proved fatal. A wider spectrum of disease is associated with underlying HIV immunosuppression than has previously been described in Africa.

Acute Disease↗