Peter Waiyaki

Life-threatening bacteraemia in HIV-1 seropositive adults admitted to hospital in Nairobi, Kenya

During 6 months, 506 consecutive adult emergency admissions to hospital in Nairobi were enrolled in a study of bacteraemia and HIV infection. 19% were HIV-1 antibody positive. Significantly more HIV-seropositive than seronegative patients had bacteraemia (26% vs 6%). The predominant organisms isolated from the seropositive patients were Salmonella typhimurium and Streptococcus pneumoniae. Mortality was higher in the seropositive than in the seronegative bacteraemic patients. The findings suggest that non-opportunistic bacteria are important causes of morbidity and mortality in HIV-infected individuals in Africa.

Prevalence of enteric pathogens among international travelers with diarrhea acquired in Kenya (Mombasa), India (Goa), or Jamaica (Montego Bay)

Stools from tourists from Europe and North America who acquired diarrhea in Mombasa (Kenya), Goa (India), or Montego Bay (Jamaica) were examined for enteric pathogens. Enterotoxigenic Escherichia coli (ETEC) was the most common pathogen (25%) identified in the 3 locations. Isolation of Shigella species was more frequent in Goa and Mombasa than in Montego Bay (10%, 9%, and 0.3%, respectively; P <.005). Viruses (rotaviruses and enteric adenoviruses) were found in 9% of travelers to the 3 areas. Of 275 ETEC isolates in this study, 158 (57%) produced a defined colonization factor antigen (CFA). Coli surface 6 (CS6) was the most frequent and was found in 41%-52% of CFA/CS-positive ETEC isolates. The frequency of resistance among bacterial enteropathogens to traditional antimicrobial agents was particularly high throughout the study period in all 3 regions. Quinolones were active against the bacterial enteropathogens in the 3 sites.

Risk and aetiology of diarrhoea at various tourist destinations.

Almost two of three tourists developed travellers diarrhoea during 2-week stays at high-risk destinations. Large differences in infection rates between hotels were seen. Patients with milder forms of diarrhoea show a similar chronology to those more severely affected. Although enterotoxigenic Escherichia coil was the most frequent cause, viral pathogens were detected more often than in other studies.

PREVENTION OF TRANSMISSION OF HUMAN IMMUNODEFICIENCY VIRUS IN AFRICA: EFFECTIVENESS OF CONDOM PROMOTION AND HEALTH EDUCATION AMONG PROSTITUTES

Condom use was assessed after a programme of education about the acquired immunodeficiency syndrome and a condom distribution programme in a well-characterised prostitute population in Nairobi. Women received their education at group meetings (barazas) and at individual counselling sessions during which they were given the results of serological tests for the human immunodeficiency virus (group 1) or at barazas only (group 2), or through very little of either (group 3). During the counselling sessions free condoms were distributed. Before either of the programmes started, 10%, 9%, and 7% of groups 1, 2, and 3 women, respectively, reported occasional use of condoms. By November 1986, 80%, 70%, and 58% of groups 1, 2, and 3 women, respectively, reported at least some condom use. The mean frequency of condom use was 38.7 (SD 31.8)%, 34.6 (34.5)%, and 25.6 (29.5)% of sexual encounters in groups 1, 2, and 3 women. 20 of 28 women who were non-condom-users seroconverted compared with 23 of 50 women who reported some use of condoms.

HIV infection among lower socioeconomic strata prostitutes in Nairobi.

A cohort of 418 lower socioeconomic strata prostitutes were enrolled in a study of the epidemiology of sexually transmitted diseases (STDs) between January and April 1985. Sixty-two per cent of the women were seropositive for HIV infection at enrollment. Significant associations were found between HIV seropositivity and Tanzanian origin (OR = 2.12, CI 95% = 1.18-3.81, P less than 0.03), younger age, a shorter duration of prostitution, reduced fecundity, use of oral contraceptives (OR = 1.8, CI 95% = 1.1-2.9, P less than 0.05) and genital ulcer disease (OR = 3.32, P less than 0.00001). No associations were noted with other STD. Stepwise logistic regression analysis confirmed independent associations between HIV infection and Tanzanian origin (OR = 2.27, CI 95% = 1.25-4.14, P less than 0.007), reduced fecundity (OR = 0.83, CI 95% = 0.74-0.94, P less than 0.003), oral contraceptive use (OR = 2.02, CI 95% = 1.22-3.35, P less than 0.006) and duration of prostitution (OR = 0.39, CI 95% = 0.23-0.65, P less than 0.004). Oral contraceptives may increase susceptibility to HIV or may be a marker for other factors which increase risk of acquisition. Further studies are necessary to confirm this association.

Therapy of travelers’ diarrhea with rifaximin on various continents

OBJECTIVE:Our aim was to compare the efficacy and safety of rifaximin, a virtually nonabsorbed antibiotic, 600 and 1200 mg per day, with placebo in patients with travelers’ diarrhea.METHODS:This was a multicenter, 1:1:1 randomized, parallel-group, double-blind study, conducted in Antigua, Guatemala; Guadalajara and Morelia, Mexico; and the coast of Kenya north and south of Mombasa. Adult patients with acute travelers’ diarrhea were recruited; exclusion criteria included primarily medication that could influence the outcome. Subjects were treated for 3 days, three times daily; follow-up lasted 5 days. For each 24-h period, the subjects completed a diary card. Pre- and posttreatment stool, blood, and urine samples were assessed.RESULTS:Among the 380 volunteers, median time to the last unformed stool was 32.5 and 32.9 h in both rifaximin groups, compared with 60.0 h with placebo (p = 0.0001). Also, secondary clinical outcome measures were favorably influenced by the active agent. No relevant side effects were reported.CONCLUSION:Rifaximin is efficacious and safe for treatment of travelers’ diarrhea at daily doses of 600 mg or higher.

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.

Extrapulmonary and disseminated tuberculosis in HIV-1-seropositive patients presenting to the acute medical services in Nairobi.

We studied 506 consecutive adult acute medical admissions to hospital in Nairobi; 95 (18.8%) were seropositive for HIV-1, and 43 new cases of active tuberculosis (TB) were identified. TB was clearly associated with HIV infection, occurring in 17.9% of seropositive patients compared with 6.3% of seronegatives [odds ratio (OR) 3.2; 95% confidence limits (CL) 1.6-6.5]. Extrapulmonary disease was more common in seropositive than seronegative TB patients (nine out of 17 versus five out of 26; OR 4.7; 95% CL 1.01-23.6); this accounted for most of the excess cases of TB seen in seropositive patients. Mycobacteraemia was demonstrated in two of eight seropositive TB patients but in none of 11 seronegative TB patients. No atypical mycobacteria were isolated. The World Health Organization (WHO) clinical case definition for African AIDS did not discriminate well between seropositive and seronegative TB cases. Five out of seven seropositive women with active tuberculosis had delivered children in the preceding 6 months and were lactating, compared with only one out of eight seronegative tuberculous women. An association between recent childbirth, HIV immunosuppression and the development of TB is suggested.

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 ocmprehensive aetiological studies have 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 diarrhoca; 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 diarrhoca 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 Escherichica 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; 285) 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.

Antimicrobial-Resistant Bacterial Diarrhea in Rural Western Kenya

Bacterial diarrheal diseases cause substantial morbidity and mortality in sub-Saharan Africa, but data on the epidemiology and antimicrobial susceptibility patterns of enteric bacterial pathogens are limited. Between May 1997 and April 1998, a clinic-based surveillance for diarrheal disease was conducted in Asembo, a rural area in western Kenya. In total, 729 diarrheal specimens were collected, and 244 (33%) yielded >or=1 bacterial pathogen, as determined by standard culture techniques; 107 (44%) Shigella isolates, 73 (30%) Campylobacter isolates, 45 (18%) Vibrio cholerae O1 isolates, and 33 (14%) Salmonella isolates were identified. Shigella dysenteriae type 1 accounted for 22 (21%) of the Shigella isolates. Among 112 patients empirically treated with an antimicrobial agent and whose stool specimens yielded isolates on which resistance testing was done, 57 (51%) had isolates that were not susceptible to their antimicrobial treatment. Empiric treatment strategies for diarrheal disease in western Kenya need to be reevaluated, to improve clinical care.