Resistance of Anopheles gambiae sensu lato to Pirimiphos-methyl Insecticide in Kakamega County, Highlands of Western Kenya.

Background: Insecticide treated bed nets and Indoor residual spraying remains the principal interventional malaria control strategies. To achieve malaria disease eradication, vector control programmes that monitor insecticide resistance profiles are necessary. Objective: The study evaluated pirimiphos-methyl susceptibility of Anopheles gambiae sensu lato in Kakamega County, western Kenya. Methods: Adult Anopheles gambiae sensu lato mosquitoes were assayed using World Health Organization tube bioassay against 0.25% pirimiphos-methyl. Susceptible and non-susceptible populations were characterized to species-level using Polymerase Chain Reaction. Susceptible and resistant mosquitoes were further subjected to G119S Acetylcholisterase (ace 1R) mutation detection. Results: Anopheles arabiensis was the predominant species in all study population Mumias east (62%), Malava (68%), Ikolomani (77%) and Lurambi (82%). Results showed phenotypic susceptibility to pirimiphos-methyl. Mortality was low in Mumias east (80.6%) and high in Lurambi (89.0%). G119S mutations ranged from 3.0% to 8.9% in Anopheles arabiensis whereas G119S mutations were relatively low ranging from 0.0% to 3.1% in Anopheles gambiae s.s populations. Study populations tested were consistent with Hardy-Weinberg equilibrium (P>0.05). Conclusion: We observed pirimiphos-methyl resistance in Anopheles arabiensis and Anopheles gambiae s.s. study populations. Results showed G119S mutation in resistance population. Resistance monitoring and management are urgently required.

Epidemiological patterns and antimicrobial resistance of bacterial diarrhea among children in Nairobi City, Kenya.

AIM: Determine the prevalence of enteric bacterial pathogens and their antimicrobial resistance among diarrheic children in Nairobi City, Kenya. BACKGROUND: Regardless of enteric bacterial pathogens being a major cause of gastroenteritis in children, their occurrence and antimicrobial resistance patterns reveals regional spatial and temporal variation. METHODS: In a cross-sectional study, a total of 374 children below five years presenting with diarrhea at Mbagathi County Hospital were recruited. Stool microbiology test was used to detect enteric bacterial infection. Antimicrobial resistance was determined using the disk diffusion method. RESULTS: Diarrheagenic E. coli (36.4%) was the leading species followed by Shigella (3.2%), Salmonella (2.4%), Campylobacter (1.6%), Yersinia (1.3%) and Aeromonas (1.1%) species. Escherichia coli pathotyping revealed that 20.9%, 4.0%, 10.2% and 0.5% of the study participants were infected with enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC) and enteroinvasive E. coli (EIEC) pure isolates while the prevalence of mixed pathotype infections was 0.3% for EAEC/EPEC/ETEC and 0.5% for EAEC/ETEC. Shigella sero-grouping revealed that 0.5%, 0.3%, 1.9%, and 0.5% were infected with Shigella boydii, Shigella dysentriae, Shigella flexneri and Shigella sonnei pure isolates. Shigella species and E. coli co-infection was detected in 2.4% of the children, specifically, 1.1% for EAEC/Shigella boydii, 0.5% for EAEC/Shigella dysentriae and 0.3% in each case of EAEC/Shigella sonnei, EPEC/Shigella flexneri and ETEC/Shigella flexneri co-infections. Most of the isolates were resistant to commonly prescribed antibiotics. CONCLUSION: There was a high prevalence of enteric bacterial pathogens and co-infection alters epidemiological dynamics of bacterial diarrhea in children. Continuous antibiotic resistance surveillance is justified because the pathogens were highly resistant to commonly prescribed antimicrobials.

Influence of blood group, Glucose-6-phosphate dehydrogenase and Haemoglobin genotype on Falciparum malaria in children in Vihiga highland of Western Kenya.

BACKGROUND: Genetic diversity of ABO blood, glucose-6-phosphate dehydrogenase (G6PD) deficiency and haemoglobin type and their ability to protect against malaria vary geographically, ethnically and racially. No study has been carried out in populations resident in malaria regions in western Kenya. METHOD: A total of 574 malaria cases (severe malaria anaemia, SMA = 137 and non-SMA = 437) seeking treatment at Vihiga County and Referral Hospital in western Kenya, were enrolled and screened for ABO blood group, G6PD deficiency and haemoglobin genotyped in a hospital-based cross-sectional study. RESULT: When compared to blood group O, blood groups A, AB and B were not associated with SMA (P = 0.380, P = 0.183 and P = 0.464, respectively). Further regression analysis revealed that the carriage of the intermediate status of G6PD was associated with risk to SMA (OR = 1.52, 95%CI = 1.029-2.266, P = 0.035). There was, however, no association between AS and SS with severe malaria anaemia. Co-occurrence of both haemoglobin type and G6PD i.e. the AA/intermediate was associated with risk to SMA (OR = 1.536, 95%CI = 1.007-2.343, P = 0.046) while the carriage of the AS/normal G6PD was associated with protection against SMA (OR = 0.337, 95%CI = 0.156-0.915, P = 0.031). CONCLUSION: Results demonstrate that blood group genotypes do not have influence on malaria disease outcome in this region. Children in Vihiga with blood group O have some protection against malaria. However, the intermediate status of G6PD is associated with risk of SMA. Further, co-inheritance of sickle cell and G6PD status are important predictors of malaria disease outcome. This implies combinatorial gene function in influencing disease outcome.

Phenotypic and Genotypic Antibiotic Resistant diarrheagenic Escherichia coli pathotypes isolated from Children with Diarrhea in Nairobi City, Kenya.

BACKGROUND: The marked genome plasticity of diarrheagenic Escherichia coli promotes emergence of pathotypes displaying unique phenotypic and genotypic resistance. This study examined phenotypic and genotypic antibiotic resistant diarrheagenic Escherichia coli pathotypes among children in Nairobi City, Kenya. METHODS: In a cross-sectional study, diarrheagenic Escherichia coli pathotypes were isolated from stool samples and their phenotypic and genotypic resistance against eight antimicrobial agents assayed. RESULTS: Diarrheagenic Escherichia coli was detected in 136(36.4%) children. Most of diarrheagenic Escherichia coli that were resistant to ampicillin, ceftriaxone, streptomycin, gentamycin, ciprofloxacin, chloramphenicol, erythromycin and tetracycline, harbored citm, bla CMY, aadA1, aac(3)-IV, qnr, catA, ere(A) and tet(A) corresponding resistant genes. CONCLUSION: Antimicrobial-resistant genes are highly prevalent among phenotypic resistant ETEC pathotypes indicating a possibility of horizontal gene transfer in spreading antibiotic resistant genes among E. coli pathotypes.

Escherichia coli pathotypes and Shigella sero-groups in diarrheic children in Nairobi city, Kenya.

AIM: In the present study, we investigated the prevalence of E. coli pathotypes and Shigella sero-groups and their antimicrobial profiles among diarrheic children in Nairobi city, Kenya. BACKGROUND: Although diarrheagenic E. coli pathotypes and Shigella sero-groups are leading causes of diarrhea in children under five years in developing countries, their distribution and antimicrobial resistance vary from place to place and over time in a given region. METHODS: In a cross-sectional study, we enrolled diarrheic children (n=354) under five years seeking treatment at Mbagathi Hospital, Nairobi city, Kenya,. Stool samples were collected from all children for bacterial culture. Bacterial isolation and identification was performed by conventional microbiological methods. Polymerase chain amplification was used to detect aspU, aggR, andpcvd432 for EAEC, est and elt for ETEC, eae for EPEC, stx for EHEC, and ipaH for EIEC and Shigella species. Antimicrobial profile was determined by disk diffusion method. RESULTS: The prevalence of EAEC, ETEC, EPEC (eae), EIEC (ipaH) was 21.2%, 10.5%, 4.5%, and 0.6%, respectively, while that of mixed infection was 0.6%for ETEC/EAEC and 0.3%for EAEC/EPEC/ETEC. No EHEC strain was isolated. Pathogenetic analysis for EAEC showed that5.9% carried aspU,8.2% possessed both aspU and aggR and 7.1% had a combination of aspU, aggR andpcvd432 while that of ETEC was 2.3% for elt, 6.5% for both elt and est and 1.7% for est. The combination of aspU with aggR, elt and est, and pcvd432 with aggR, aspU and est was 0.3% for each case of ETEC/EAEC mixed infection. The aspU gene co-existed with aggR, pcvd432, eae and elt in the EAEC/EPEC/ETEC mixed infection. The prevalence of S. boydii, S. dysenteriae, S. flexneriand,S. sonnei was 0.8%, 0.6%, 1.7%, and 0.8%, respectively. No E. coli pathotype and shigella co-infection was detected. In addition, both E. coli pathotypes and Shigella species were resistant to ampicillin, trimethoprim/sulfamethoxazole, streptomycin, chloramphenicol and tetracycline while gentamycin and kanamycin resistance occurred in diarrheagenic E. coli. CONCLUSION: E. coli pathotypes and Shigella sero-groups harboring virulent genes are important causes of diarrhea in children in Kenya. The increasing spectrum of antibiotic resistance in diarrheagenic E. coli and Shigella species necessitates the development of antimicrobial stewardship education-programs to influence prescribing behavior as well as optimizing the use of effective antimicrobials in Kenya.

Circulating Interferon-Gamma Levels Are Associated with Low Body Weight in Newly Diagnosed Kenyan Non-Substance Using Tuberculosis Individuals.

Although interferon-gamma, interleukin-10, and adiponectin are key immunopathogenesis mediators of tuberculosis, their association with clinical manifestations of early stage disease is inconclusive. We determined interferon-gamma, interleukin-10, and adiponectin levels in clinically and phenotypically well-characterised non-substance using new pulmonary tuberculosis patients (n = 13) and controls (n = 14) from Kenya. Interferon-gamma levels (P < 0.0001) and interferon-gamma to interleukin-10 (P < 0.001) and interferon-gamma to adiponectin (P = 0.027) ratios were elevated in tuberculosis cases. Correlation analyses in tuberculosis cases showed associations of interferon-gamma levels with body weight (ρ = -0.849; P < 0.0001), body mass index (ρ = 0.664; P = 0.013), hip girth (ρ = -0.579; P = 0.038), and plateletcrit (ρ = 0.605; P = 0.028); interferon-gamma to interleukin-10 ratio with diastolic pressure (ρ = -0.729; P = 0.005); and interferon-gamma to adiponectin ratio with body weight (ρ = -0.560; P = 0.047), body mass index (ρ = -0.604; P = 0.029), and plateletcrit (ρ = 0.793; P = 0.001). Taken together, our results suggest mild-inflammation in early stage infection characterised by upregulation of circulating interferon-gamma production in newly infected TB patients.

HIV-1 protease inhibitor drug resistance in Kenyan antiretroviral treatment-naive and -experienced injection drug users and non-drug users.

BACKGROUND: Although injection drug use drives antiretroviral drug resistance, the prevalence of protease inhibitor (PI) resistance among Kenyan IDUs remains undetermined. We, therefore, explored PI resistance mutations and their association with viral load and CD4+ T cell counts in HIV-1 infected IDUs (ART-naive, n = 32; and -experienced, n = 47) and non-drug users (ART-naive, n = 21; and -experienced, n = 32) naive for PI treatment from coastal Kenya. RESULTS: Only IDUs harboured major PI resistance mutations consisting of L90M, M46I and D30 N among 3 (6.4 %) ART-experienced and 1 (3.1 %) -naive individuals. Minor PI mutations including A71T, G48E, G48R, I13V, K20I, K20R, L10I, L10V, L33F, L63P, T74S, V11I, and V32L were detected among the ART-experienced (36.2 vs. 46.9 %) and -naive (43.8 vs. 66.7 %) IDUs and non-drug users, respectively. All the four IDUs possessing major mutations had high viral load while three presented with CD4+ T cell counts of <500 cells/ml. Among the ART-naive non-drug users, CD4+ T cell counts were significantly lower in carriers of minor mutations compared to non-carriers (P < 0.05). CONCLUSION: Transmitted drug resistance may occur in IDUs underscoring the need for genotyping resistance before initiating PI treatment.

Serum adiponectin in HIV-1 and hepatitis C virus mono- and co-infected Kenyan injection drug users.

Adiponectin is an important marker of anthropometric profiles of adipose tissue. However, association of adiponectin and adiposity in HIV mono- and co-infected and hepatitis (HCV) injection drug users (IDUs) has not been elucidated. Therefore, the relationship of total adiponectin levels with anthropometric indices of adiposity was examined in HIV mono-infected (anti-retroviral treatment, ART-naive, n=16 and -experienced, n=34); HCV mono-infected, n=36; HIV and HCV co-infected (ART-naive, n=5 and -experienced, n=13); uninfected, n=19 IDUs; and healthy controls, n=16 from coastal Kenya. Anthropometric indices of adiposity were recorded and total circulating adiponectin levels were measured in serum samples using enzyme-linked immunosorbent assay. Adiponectin levels differed significantly amongst the study groups (P<0.0001). Post-hoc analyses revealed decreased levels in HIV mono-infected ART-naive IDUs in comparison to uninfected IDUs (P<0.05) and healthy controls (P<0.05). However, adiponectin levels were elevated in HCV mono-infected IDUs relative to HIV mono-infected ART-naive (P<0.001) and -experienced (P<0.001) as well as HIV and HCV co-infected ART-naive (P<0.05) IDUs. Furthermore, adiponectin correlated with weight (ρ=0.687; P=0.003) and BMI (ρ=0.598; P=0.014) in HIV mono-infected ART-naive IDUs; waist circumference (ρ=-0.626; P<0.0001), hip (ρ=-0.561; P=0.001) circumference, and bust-to-waist ratio (ρ=0.561; P=0.001) in HIV mono-infected ART-experienced IDUs; waist girth (ρ=0.375; P=0.024) in HCV mono-infected IDUs; and waist-to-hip ratio (ρ=-0.872; P=0.048) in HIV and HCV co-infected ART-naive IDUs. Altogether, these results suggest suppression of adiponectin production in treatment-naive HIV mono-infected IDUs and that circulating adiponectin is a useful surrogate marker of altered adiposity in treatment-naive and -experienced HIV and HCV mono- and co-infected IDUs.

Hepatitis B virus sero-profiles and genotypes in HIV-1 infected and uninfected injection and Non-injection drug users from coastal Kenya.

BACKGROUND: Information about HBV sero-markers, infection stages and genotypes in HIV-1 infected and uninfected injection and non-injection drug users (IDUs) in Kenya remains elusive. METHODS: A cross-sectional study examining HBV sero-marker, infection stages and genotypes was conducted among HIV-1 infected and uninfected, respectively, IDUs (n = 157 and n = 214) and non-IDUs (n = 139 and n = 48), and HIV-1 uninfected non-drug using controls (n = 194) from coastal, Kenya. HBV sero-marker and infection stages were based on HBV 5-panel rapid test plasma sero-reactivity. DNA was extracted from acute and chronic plasma samples and genotypes established by nested-PCR and direct sequencing. RESULTS: HBsAg positivity was higher in HIV-1 infected IDUs (9.6%) relative to HIV-1 uninfected IDUs (2.3%), HIV-1 infected non-IDUs (3.6%), HIV-1 uninfected non-IDUs (0.0%) and non-drug users (2.6%; P = 0.002). Contrastingly, HBsAb positivity was higher in HIV-1 uninfected IDUs (14.6%) and non-IDUs (16.8) in comparison to HIV-1 infected IDUs (8.3%), and non-IDUs (8.6%), and non-drug users (8.2%; P = 0.023). HBcAb positivity was higher in HIV-1 infected IDUs (10.2%) compared to HIV-1 uninfected IDUs (3.3%), HIV-1 infected non-IDUs (6.5%), HIV-1 uninfected non-IDUs (2.1%) and non-drug users (4.6%; P = 0.038). Acute (5.7%, 1.4%, 0.0%, 0.0% and 1.5%) and chronic (5.1%, 0.9%, 3.6%, 0.0% and 1.5%) stages were higher in HIV-1 infected IDUs, compared to HIV-1 uninfected IDUs, HIV-1 infected and uninfected non-IDUs and non-drug users, respectively. However, vaccine type response stage was higher in HIV-1 uninfected IDUs (15.4%) relative to HIV-1 infected IDUs (6.4%), and HIV-1 infected (6.5%), and uninfected (10.4%) non-IDUs, and non-drug users (5.7%; P = 0.003). Higher resolved infection rates were also recorded in HIV-1 uninfected IDUs (11.2%) compared to HIV-1 infected IDUs (8.3%), and HIV-1 infected (7.2%), uninfected (6.3%) non-IDUs, and non-drug users (6.7%; P = 0.479), respectively. Only A1 genotype showing minimal diversity was detected among the study participants. CONCLUSION: HBV sero-markers and infection staging are valuable in diagnosis and genotyping of HBV infections. Among IDUs, higher HBsAg and HBcAb positivity in HIV-1 infected and higher HBsAb positivity in HIV-1 negative IDUs suggests frequent exposure. Additionally, HBV genotype A is the dominant circulating genotype in both high and low risk populations of Kenya.