Oxacillin resistant Staphylococcus aureus among HIV infected and non-infected Kenyan patients.

BACKGROUND: Infections due to methicillin resistant S. aureus (MRSA) present global challenges to clinicians since therapeutic options are limited and suboptimal dosing contributes to heightened mortality and increased length of hospital stay particularly among the HIV infected patients. OBJECTIVES: To assess the prevalence and relative risk of MRSA infections in HIV infected patients. DESIGN: Cross sectional analytical study. SETTING: Kenya Medical Research Institute, Opportunistic Infection Laboratories in Nairobi. SUBJECTS: Four hundred and thirty six male and female patients aged one to 65 years, of whom 220 were HIV-infected and 216 were non-infected. RESULTS: There was 436 male (57.1%) and female (42.9%) respondents. The prevalence of MRSA was 26.3% with majority infecting the HIV infected patients (P=0.046). Likewise, the overall Staphylococcal infections were more common in HIV patients (P <0.001). The common test for MRSA oxacillin disk diffusion had a sensitivity and specificity of 100% and 92%. CONCLUSION: HIV is a predisposing factor to Staphylococcal infection and there are indications that treatment with beta-lactam antibiotics may no longer be relied on as sole empiric therapy for several ill HIV patients whose infections may be of MRSA in origin. There is need for an informed choice in administration of appropriate antibiotics in order to minimise treatment failures due to the multidrug resistance and Vanvomycin intermediate S. aureus (VISA) strains. Molecular epidemiology of MRSA strains in understanding new and emerging trends is recommended.

Pneumocystis jirovecii and microbiological findings in children with severe pneumonia in Nairobi, Kenya.

OBJECTIVE: To determine the significance of Pneumocystis jirovecii infection in the Kenyan paediatric population. DESIGN: Sixty samples of induced sputum from children aged < or =23 months, half of whom were human immunodeficiency virus (HIV) positive, admitted with severe pneumonia in Nairobi were subjected to immunofluorescent staining for detection of P. jirovecii and microbiological culture. RESULTS: P. jirovecii was detected in 8/60 (13%) as a copathogen with other respiratory pathogens. Five of eight samples with >5 oocysts were from HIV-positive children aged < or =6 months, while equivocally scored samples (< or =5 oocysts) were from HIV-negative children aged >6 months. Klebsiella pneumoniae was significantly recovered in 26/ 60 (43%), followed by Escherichia coli 11/60 (18%) and Staphylococcus aureus 8/60 (13%). Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa were isolated infrequently. Candida albicans was recovered from 27/60 (45%), while the frequency of C. tropicalis, C. glabrata and C. parapsilosis was 7%, 5% and 3% respectively. Multidrug resistance among E. coli and K. pneumoniae were: sulphamethoxazoletrimethoprim 100% vs. 69%, chloramphenicol 55% vs. 73% and ampicillin 100% vs. 89%. CONCLUSION: Paediatricians in Kenya should be aware of Pneumocystis pneumonia, irrespective of the patient's HIV status.

Detection of virulence-related genes by multiplex PCR in multidrug-resistant diarrhoeagenic Escherichia coli isolates from Kenya and Japan.

We compared serotypes, drug susceptibility and presence of virulence-related genes in diarrhoeagenic Escherichia coli isolates from children < 5 years from Kenya (n = 82) and Japan (n = 47). Multiplex PCR was used to detect genes coding for enteroaggregative adherence (aggR), heat-stable toxin (st), heat-labile toxin (It), verotoxin (vt), attaching and effacing mechanism (eaeA), enteroaggregative E. coli heat-stable enterotoxin 1 (astA) and enteroinvasive mechanism (invE). Kenyan E. coli O-serotypes were more diverse than those from Japan (29 vs. 12 serotypes) and exhibited high level multidrug resistance to World Health Organization (WHO) recommended antibiotics. Resistance rates to tetracycline, ampicillin and sulphamethoxazole-trimethoprim were 70.7, 65.9 and 68.3% respectively, but resistance to sulphamethoxazole-trimethoprim among the E. coli isolates from Japan was low (21%). Kenyan isolates harboured virulence-related genes in high frequency (82.9%) compared to those from Japan (25.5%) with aggR and astA being the most frequently detected genes. The presence of multiple virulence genes was associated with multidrug resistance and this merits further investigation.

Pneumocystis carinii pneumonia in HIV/AIDS patients at an urban district hospital in Kenya.

BACKGROUND: Pneumocystis carinii pneumonia has generally been regarded to be an uncommon opportunistic infection in HIV infected individuals in sub-Saharan Africa. The reason for this has not been clear but postulates included a lack of suitable pathogenic types in the African environment, diagnostic difficulties and the more commonly held belief that African HIV infected individuals were dying early from common non-opportunistic pathogens before severe degrees of immunosuppression occured. Recently a trend has emerged at the Mbagathi district hospital whereby an increasing number of HIV infected patients are empirically treated for Pneumocystis carinii pneumonia (PCP) based on clinical and radiological features. OBJECTIVE: To determine the prevalence of PCP and clinical outcomes of HIV infected patients presenting at the Mbagathi District Hospital, Nairobi with the presumptive diagnosis of PCP. SETTING: Mbagathi District Hospital, a 169-bed public hospital in Nairobi, Kenya. METHODS: Patients presenting with a sub-acute onset of cough and dyspnoea were eligible for the study if they were found to have bilateral pulmonary shadows and had negative sputum smears for AFBS. Consenting patients who had no contraindication to fiberoptic bronchoscopy had a clinical evaluation which was followed with a fiberoptic bronchoscopy procedure where bronchoalveolar lavage fluid (BALF) was obtained. BALF was examined for cysts of P. carinii using toluidine blue stain and immunofluorescent antibody test (IFAT). BALF was also processed for fungi, bacteria and mycobacteria using routine procedures. Standard treatment with high dose cotrimoxazole was offered to all patients who were then followed up until discharge from hospital or death whichever came first. RESULTS: Between June 1999 and August 2000 a total of 63 patients were referred for bronchoscopy. Of these four declined to undergo the fiberoptic bronchoscopy procedure, four died before the procedure could be done, one was judged too sick to undergo the procedure and three had been on cotrimoxazole for longer than five days. Thus 51 patients underwent bronchoscopy. Pneumocystis carinii stain was positive in 19 (37.2%) while death occured in 16 (31.4%) of the 51 patients. There were more deaths in those without PCP but this difference was not statistically significant (odds ratio 0.68 (95% CI 0.35-1.32; P=0.2). CONCLUSION: PCP was found to be common in HIV infected patients presenting with clinical and radiological features of the disease. The mortality rate for patients with a presumptive diagnosis of PCP is high. This study suggests that cotrimoxazole preventive therapy may be a useful intervention in symptomatic HIV infected patients in Kenya for the prevention of PCP and may avert deaths from this disease.

Antifungal drug susceptibility of Candida albicans.

OBJECTIVE: To determine the susceptibility of clinical isolates of Candida albicans and to establish the minimum inhibitory concentrations (MIC) to commonly used antifungal drugs. DESIGN: Laboratory based experiment. SETTING: Mbagathi District Hospital, Nairobi, Kenya. SUBJECTS: Candida albicans isolated between 1998 and 2000 from the sputa of HIV/AIDS patients and throat swabs of children with acute respiratory infections (ARI). METHODS: Susceptibility to amphotericin B, clotrimazole, nystatin, and 5-fluorocytosine was done using agar dilution method (NCCLS 1997). RESULTS: Among the ARI isolates 29.3% and among HIV isolates 22.4% had MIC>0.5 microg/ml to amphotericin B. Over 80% of the ARI isolates had MICs > 1 microg/ml to clotrimazole. The MIC range of most isolates to nystatin was 4-16 microg/ml while most isolates were susceptible to 5-fluorocytosine. There were no significant differences in susceptibility between ARI and HIV isolates to commonly used antifungal drugs. CONCLUSION: Although fungal resistance has not been extensively studied, susceptibility tests showed some Candida albicans have increased MICs to commonly used antifungal drugs. The results call for further investigations on fungal resistance especially in the context of opportunistic infections in HIV/AIDS.