Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 22
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Methods Mol Biol ; 2182: 161-177, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32894495

RESUMO

Polymerase chain reaction (PCR) is a molecular-based technology that has revolutionized diagnostics and characterization of pathogens, and thus affecting how we understand disease landscape. This technology has been found amenable to application on various strategies for management and control of infectious diseases. The main advantage with PCR technologies, when applied optimally, is the high sensitivity and short-turn-around time for results, thus rendering the strategy attractive to researchers in infectious diseases and public health. In this chapter, we describe PCR approaches that are innovative and easy to deploy in a laboratory with medium range infrastructure investment.

2.
Nat Microbiol ; 5(6): 787-795, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32467623

RESUMO

Antimicrobial resistance (AMR) is a growing public health challenge that is expected to disproportionately burden lower- and middle-income countries (LMICs) in the coming decades. Although the contributions of human and veterinary antibiotic misuse to this crisis are well-recognized, environmental transmission (via water, soil or food contaminated with human and animal faeces) has been given less attention as a global driver of AMR, especially in urban informal settlements in LMICs-commonly known as 'shanty towns' or 'slums'. These settlements may be unique hotspots for environmental AMR transmission given: (1) the high density of humans, livestock and vermin living in close proximity; (2) frequent antibiotic misuse; and (3) insufficient drinking water, drainage and sanitation infrastructure. Here, we highlight the need for strategies to disrupt environmental AMR transmission in urban informal settlements. We propose that water and waste infrastructure improvements tailored to these settings should be evaluated for their effectiveness in limiting environmental AMR dissemination, lowering the community-level burden of antimicrobial-resistant infections and preventing antibiotic misuse. We also suggest that additional research is directed towards developing economic and legal incentives for evaluating and implementing water and waste infrastructure in these settings. Given that almost 90% of urban population growth will occur in regions predicted to be most burdened by the AMR crisis, there is an urgent need to build effective, evidence-based policies that could influence massive investments in the built urban environment in LMICs over the next few decades.


Assuntos
Anti-Infecciosos/farmacologia , Doenças Transmissíveis/epidemiologia , Doenças Transmissíveis/transmissão , Resistência Microbiana a Medicamentos , Exposição Ambiental , Saúde da População Urbana , Reforma Urbana , Doenças Transmissíveis/tratamento farmacológico , Doenças Transmissíveis/microbiologia , Meio Ambiente , Humanos , Saneamento , Águas Residuárias
3.
Infect Genet Evol ; 78: 104121, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31756512

RESUMO

Resistance to the mainstay antimalarial drugs is a major concern in the control of malaria. Delayed Plasmodium falciparum parasite clearance has been associated with Single Nucleotide Polymorphisms (SNPs) in the kelch propeller region (K13). However, SNPs in the Pf-adaptor protein complex 2 mu subunit (Pfap2-mu), Pfcrt and Pfmdr1 are possible markers associated with multi-drug resistance. Here, we explored the prevalence of SNPs in the K13, Pfap2-mu, Pfcrt, and Pfmdr1 in 94 dried blood spot field isolates collected from children aged below 12 years infected with P. falciparum during a cross-sectional study. The samples were collected in 2015 during the peak malaria transmission season in the Nyando region of Western Kenya before treatment with Artemether-Lumefantrine, the first-line artemisinin-based combination therapy (ACT) in Kenya. However, 47 of the 94 samples had recurrent parasitemia and were interrogated for the presence of the SNPs in K13 and Pfap2-mu. We used PCR amplification and sequencing to evaluate specific regions of K13 (codons 432-702), Pfap2-mu (codons 1-350), Pfmdr1 (codons 86, 1034-1246), and Pfcrt (codons 72-76) gene(s). The majority of parasites harbored the wild type K13 sequence. However, we found a unique non-synonymous W611S change. In silico studies on the impact of the W611S predicted structural changes in the overall topology of the K13 protein. Of the 47 samples analyzed for SNPs in the Pfap2-mu gene, 14 (29%) had S160 N/T mutation. The CVIET haplotype associated with CQ resistance in the Pfcrt yielded a 7.44% (7/94), while CVMNK haplotype was at 92.56%. Mutations in the Pfmdr1 region were detected only in three samples (3/94; 3.19%) at codon D1246Y. Our data suggest that parasites in the western part of Kenya harbor the wildtype strains. However, the detection of the unique SNP in K13 and Pfap2-mu linked with ACT delayed parasite clearance may suggest slow filtering of ACT-resistant parasites.

4.
Int J Antimicrob Agents ; 54(5): 531-537, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31437486

RESUMO

There are substantial limitations in understanding of the distribution of antimicrobial resistance (AMR) in humans and livestock in developing countries. This papers present the results of an epidemiological study examining patterns of AMR in Escherichia coli isolates circulating in sympatric human (n = 321) and livestock (n = 633) samples from 99 households across Nairobi, Kenya. E. coli isolates were tested for susceptibility to 13 antimicrobial drugs representing nine antibiotic classes. High rates of AMR were detected, with 47.6% and 21.1% of isolates displaying resistance to three or more and five or more antibiotic classes, respectively. Human isolates showed higher levels of resistance to sulfonamides, trimethoprim, aminoglycosides and penicillins compared with livestock (P<0.01), while poultry isolates were more resistant to tetracyclines (P = 0.01) compared with humans. The most common co-resistant phenotype observed was to tetracyclines, streptomycin and trimethoprim (30.5%). At the household level, AMR carriage in humans was associated with human density (P<0.01) and the presence of livestock manure (P = 0.03), but keeping livestock had no influence on human AMR carriage (P>0.05). These findings revealed a high prevalence of AMR E. coli circulating in healthy humans and livestock in Nairobi, with no evidence to suggest that keeping livestock, when treated as a single risk factor, contributed significantly to the burden of AMR in humans, although the presence of livestock waste was significant. These results provide an understanding of the broader epidemiology of AMR in complex and interconnected urban environments.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/fisiologia , Infecções por Escherichia coli/epidemiologia , Escherichia coli/efeitos dos fármacos , Gado/microbiologia , Aves Domésticas/microbiologia , Aminoglicosídeos/farmacologia , Animais , Estudos Transversais , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/tratamento farmacológico , Humanos , Quênia/epidemiologia , Testes de Sensibilidade Microbiana , Penicilinas/farmacologia , Sulfonamidas/farmacologia , Tetraciclinas/farmacologia , Trimetoprima/farmacologia
5.
Lancet Planet Health ; 3(6): e259-e269, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31229001

RESUMO

BACKGROUND: Antimicrobial resistance is one of the great challenges facing global health security in the modern era. Wildlife, particularly those that use urban environments, are an important but understudied component of epidemiology of antimicrobial resistance. We investigated antimicrobial resistance overlap between sympatric wildlife, humans, livestock, and their shared environment across the developing city of Nairobi, Kenya. We use these data to examine the role of urban wildlife in the spread of clinically relevant antimicrobial resistance. METHODS: 99 households across Nairobi were randomly selected on the basis of socioeconomic stratification. A detailed survey was administered to household occupants, and samples (n=2102) were collected from the faeces of 75 wildlife species inhabiting household compounds (ie, the household and its perimeter; n=849), 13 livestock species (n=656), and humans (n=333), and from the external environment (n=288). Escherichia coli, our sentinel organism, was cultured and a single isolate from each sample tested for sensitivity to 13 antibiotics. Diversity of antimicrobial resistant phenotypes was compared between urban wildlife, humans, livestock, and the environment, to investigate whether wildlife are a net source for antimicrobial resistance in Nairobi. Generalised linear mixed models were used to determine whether the prevalence of antimicrobial resistant phenotypes and multidrug-resistant E coli carriage in urban wildlife is linked to variation in ecological traits, such as foraging behaviour, and to determine household-level risk factors for sharing of antimicrobial resistance between humans, wildlife, and livestock. FINDINGS: E coli were isolated from 485 samples collected from wildlife between Sept 6,2015, and Sept 28, 2016. Wildlife carried a low prevalence of E coli isolates susceptible to all antibiotics tested (45 [9%] of 485 samples) and a high prevalence of clinically relevant multidrug resistance (252 [52%] of 485 samples), which varied between taxa and by foraging traits. Multiple isolates were resistant to one agent from at least seven antimicrobial classes tested for, and a single isolate was resistant to all antibiotics tested for in the study. The phenotypic diversity of antimicrobial-resistant E coli in wildlife was lower than in livestock, humans, and the environment. Within household compounds, statistical models identified two interfaces for exchange of antimicrobial resistance: between both rodents, humans and their rubbish, and seed-eating birds, humans and their rubbish; and between seed-eating birds, cattle, and bovine manure. INTERPRETATION: Urban wildlife carry a high burden of clinically relevant antimicrobial-resistant E coli in Nairobi, exhibiting resistance to drugs considered crucial for human medicine by WHO. Identifiable traits of the wildlife contribute to this exposure; however, compared with humans, livestock, and the environment, low phenotypic diversity in wildlife is consistent with the hypothesis that wildlife are a net sink rather than source of clinically relevant resistance. Wildlife that interact closely with humans, livestock, and both human and livestock waste within households, are exposed to more antimicrobial resistant phenotypes, and could therefore act as conduits for the dissemination of clinically relevant antimicrobial resistance to the wider environment. These results provide novel insight into the broader epidemiology of antimicrobial resistance in complex urban environments, characteristic of lower-middle-income countries. FUNDING: UK Medical Research Council and CGIAR Research Program on Agriculture for Nutrition and Health.


Assuntos
Animais Domésticos/microbiologia , Animais Selvagens/microbiologia , Farmacorresistência Bacteriana , Infecções por Escherichia coli/veterinária , Escherichia coli/efeitos dos fármacos , Esterco/microbiologia , Animais , Antibacterianos/farmacologia , Infecções por Escherichia coli/epidemiologia , Quênia/epidemiologia , Gado/microbiologia , Prevalência , Aves Canoras/microbiologia
7.
Nature ; 565(7738): 230-233, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30602788

RESUMO

Yemen is currently experiencing, to our knowledge, the largest cholera epidemic in recent history. The first cases were declared in September 2016, and over 1.1 million cases and 2,300 deaths have since been reported1. Here we investigate the phylogenetic relationships, pathogenesis and determinants of antimicrobial resistance by sequencing the genomes of Vibrio cholerae isolates from the epidemic in Yemen and recent isolates from neighbouring regions. These 116 genomic sequences were placed within the phylogenetic context of a global collection of 1,087 isolates of the seventh pandemic V. cholerae serogroups O1 and O139 biotype El Tor2-4. We show that the isolates from Yemen that were collected during the two epidemiological waves of the epidemic1-the first between 28 September 2016 and 23 April 2017 (25,839 suspected cases) and the second beginning on 24 April 2017 (more than 1 million suspected cases)-are V. cholerae serotype Ogawa isolates from a single sublineage of the seventh pandemic V. cholerae O1 El Tor (7PET) lineage. Using genomic approaches, we link the epidemic in Yemen to global radiations of pandemic V. cholerae and show that this sublineage originated from South Asia and that it caused outbreaks in East Africa before appearing in Yemen. Furthermore, we show that the isolates from Yemen are susceptible to several antibiotics that are commonly used to treat cholera and to polymyxin B, resistance to which is used as a marker of the El Tor biotype.


Assuntos
Cólera/epidemiologia , Cólera/microbiologia , Genoma Bacteriano/genética , Genômica , Vibrio cholerae/genética , Vibrio cholerae/isolamento & purificação , Humanos , Filogenia , Vibrio cholerae/classificação , Iêmen/epidemiologia
8.
BMC Res Notes ; 12(1): 22, 2019 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-30642404

RESUMO

OBJECTIVE: Increase in antimicrobial resistance is a threat to health sector globally. Surveillance on the spread and emergence of antimicrobial resistance is therefore invertible. This study investigated prevalence of Salmonella and Escherichia coli, molecularly characterized their antimicrobial resistance patterns and spread among resistant isolates from chicken droppings. RESULTS: A total of 150 chicken households were selected randomly within Nairobi and fresh chicken droppings collected. Salmonella and Escherichia coli were isolated and antimicrobial susceptibility test carried out. Beta-lactamase genes and class 1 integrons were determined among amoxicillin resistant isolates. Isolates carrying TEM gene were further subjected to (GTG)5 PCR genotyping. Of the analysed samples, 57% and 12% contained Escherichia coli and Salmonella respectively. Most of the isolates were susceptible to the tested antibiotics with exemption of 53% of the isolates that were resistant to amoxicillin. The isolates were detected with TEM (46%), CTX-M (18%) resistance genes and class 1 integrons (25%). The study reveals presence of beta-lactamase genes and class 1 integrons across Salmonella and Escherichia coli isolates from droppings of reared chicken. Therefore, the wide distribution of chicken and their fecal waste is likely to increase development of antibiotic resistance.


Assuntos
Galinhas/microbiologia , Farmacorresistência Bacteriana , Escherichia coli , Fezes/microbiologia , Salmonella , Animais , Farmacorresistência Bacteriana/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Integrons/genética , Quênia , Testes de Sensibilidade Microbiana , Salmonella/efeitos dos fármacos , Salmonella/genética , Salmonella/isolamento & purificação , Resistência beta-Lactâmica/genética , beta-Lactamases/genética
9.
PLoS Negl Trop Dis ; 12(8): e0006658, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-30102697

RESUMO

Campylobacteriosis is a leading foodborne zoonosis worldwide, and is frequently associated with handling and consumption of poultry meat. Various studies indicate that Campylobacter causes a substantial human disease burden in low to middle-income countries, but data regarding the organism's epidemiology in countries like Kenya are scarce. In sub-Saharan Africa, 3.8 million deaths of children under-5 years of age are reported annually. Of those, 25% are caused by diarrheal diseases, and Campylobacter is one of the most frequently isolated bacteria from diarrheic children. With the growth of urban conglomerates, such as Kenya's capital, Nairobi, changes in diets, food production systems, and retailing dynamics, it is likely that exposure and susceptibility to this pathogen will change. Therefore, the importance of Campylobacter disease burden in Kenya may increase further. The objectives of this study were: 1) to determine the prevalence of Campylobacter spp. in Nairobi's small-scale chicken farms and meat retailers, and 2) to identify potential risk factors associated with its presence in those sites. The prevalence data provides the first detailed baseline for this pathogen in the urban Kenyan context. The risk factors provide context-specific insights for disease managers. A cross-sectional study of broiler, indigenous chicken farms, and chicken meat retailers, was conducted in a peri-urban, low to middle-income area (Dagoretti), and a very-low income informal settlement (Kibera) of Nairobi. Chicken faeces were collected using one pair of boot socks per farm, and 3 raw chicken meat samples were purchased per retailer. Samples were cultured for viable Campylobacter spp. using mCCDA, followed by blood agar plates in aerobic/microaerobic conditions for prevalence calculations. A questionnaire-based survey on sanitary, sourcing and selling practices was conducted at each site for risk factor identification using logistic regression analyses. A total of 171 farm premises and 53 retailers were sampled and interviewed. The prevalence results for Campylobacter spp. were between 33 to 44% for broiler and indigenous chicken farms, 60% and 64% for retailers, in Dagoretti and Kibera, respectively. Univariable logistic regression showed an association between Campylobacter spp. presence and the easiness of cleaning the display material used by the retailer. Restricting access to the flock was also associated with the pathogen's presence. Multivariable logistic regression identified the selling of defrosted meat as a retailer risk factor (OR: 4.69; 95% CI: 1.31-19.97), calling for more investigation of the reported repetitive freezing-thawing processes and cold chain improvement options. At the farm-level, having a pen floor of material not easy to clean was found to increase the risk (OR: 2.31; 95%CI: 1.06-5.37). The relatively high prevalence of Campylobacter spp. across different areas and value chain nodes indicates a clear human exposure risk. The open nature of both small-scale broiler and indigenous chicken production practices with low biosecurity, hygiene and informal transactions, likely plays a role in this. While gradual improvement of farm biosecurity is recommended, risk factors identified suggest that consumer education and enforcement of basic food safety principles at the retailer end of the food continuum represent key targets for risk reduction in informal settings.


Assuntos
Campylobacter/isolamento & purificação , Microbiologia de Alimentos , Carne/microbiologia , Animais , Galinhas , Comércio , Estudos Transversais , Fazendas , Fezes/microbiologia , Manipulação de Alimentos , Abastecimento de Alimentos , Humanos , Higiene , Quênia , Prevalência , Fatores de Risco , Inquéritos e Questionários , Zoonoses
10.
Antimicrob Agents Chemother ; 59(6): 3133-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25779570

RESUMO

Multidrug-resistant bacteria pose a major challenge to the clinical management of infections in resource-poor settings. Although nontyphoidal Salmonella (NTS) bacteria cause predominantly enteric self-limiting illness in developed countries, NTS is responsible for a huge burden of life-threatening bloodstream infections in sub-Saharan Africa. Here, we characterized nine S. Typhimurium isolates from an outbreak involving patients who initially failed to respond to ceftriaxone treatment at a referral hospital in Kenya. These Salmonella enterica serotype Typhimurium isolates were resistant to ampicillin, chloramphenicol, cefuroxime, ceftriaxone, aztreonam, cefepime, sulfamethoxazole-trimethoprim, and cefpodoxime. Resistance to ß-lactams, including to ceftriaxone, was associated with carriage of a combination of blaCTX-M-15, blaOXA-1, and blaTEM-1 genes. The genes encoding resistance to heavy-metal ions were borne on the novel IncHI2 plasmid pKST313, which also carried a pair of class 1 integrons. All nine isolates formed a single clade within S. Typhimurium ST313, the major clone of an ongoing invasive NTS epidemic in the region. This emerging ceftriaxone-resistant clone may pose a major challenge in the management of invasive NTS in sub-Saharan Africa.


Assuntos
Antibacterianos/farmacologia , Salmonella typhimurium/efeitos dos fármacos , Ampicilina/farmacologia , Proteínas de Bactérias/genética , Ceftriaxona , Cefuroxima/farmacologia , Cloranfenicol/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Quênia , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Salmonella typhimurium/genética , Sorogrupo
11.
Afr J Lab Med ; 3(1): 41, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-29043171

RESUMO

BACKGROUND: Since 1971, Kenya has had repeated cholera outbreaks. However, the cause of seasonal epidemics of cholera is not fully understood and neither are the factors that drive epidemics, both in Kenya and globally. OBJECTIVES: The objectives of the study were to determine the environmental reservoirs of V. cholerae during an interepidemic period in Kenya and to characterise their virulence factors. METHODS: One hundred (50 clinical, 50 environmental) samples were tested for V. cholerae isolates using both simplex and multiplex polymerase chain reaction. RESULTS: Both sediments and algae from fishing and landing bays yielded isolates of V. cholerae. Clinical strains were characterised along with the environmental strains for comparison. All clinical strains harboured ctxA, tcpA (El Tor), ompU, zot, ace, toxR, hylA (El Tor) and tcpI genes. Prevalence for virulence genes in environmental strains was hylA (El Tor) (10%), toxR (24%), zot (22%), ctxA (12%), tcpI (8%), hylA (26%) and tcpA (12%). CONCLUSION: The study sites, including landing bays and beaches, contained environmental V. cholerae, suggesting that these may be reservoirs for frequent epidemics. Improved hygiene and fish-handling techniques will be important in reducing the persistence of reservoirs.

12.
PLoS One ; 8(9): e74829, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24066154

RESUMO

Cholera remains a significant public health challenge in many sub-Saharan countries including Kenya. We have performed a combination of phylogenetic and phenotypic analysis based on whole genome DNA sequences derived from 40 environmental and 57 clinical V. cholerae from different regions of Kenya isolated between 2005 and 2010. Some environmental and all clinical isolates mapped back onto wave three of the monophyletic seventh pandemic V. cholerae El Tor phylogeny but other environmental isolates were phylogenetically very distinct. Thus, the genomes of the Kenyan V. cholerae O1 El Tor isolates are clonally related to other El Tor V. cholerae isolated elsewhere in the world and similarly harbour antibiotic resistance-associated STX elements. Further, the Kenyan O1 El Tor isolates fall into two distinct clades that may have entered Kenya independently.


Assuntos
Vibrio cholerae/genética , Humanos , Quênia , Dados de Sequência Molecular , Filogenia , Vibrio cholerae/classificação
13.
BMC Microbiol ; 13: 109, 2013 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-23682924

RESUMO

BACKGROUND: We determined the prevalence and evidence for physical linkage amongst integrons, insertion sequences, Tn21 and Tn7 transposons in a collection of 1327 E. coli obtained over a 19-year period from patients in Kenya. RESULTS: The prevalence of class 1 integrons was 35%, class 2 integrons were detected in 3 isolates but no isolate contained a class 3 integron. Integron lacking the 3'-CS or those linked to sul3 gene or IS26 or those containing the ISCR1 were only detected in multidrug resistant (MDR) strains. The dfrAs were the most common cassettes and their prevalence was: - dfrA1(28%), dfrA12(20%), dfA17(9%), dfrA7(9%), and dfrA16(5%). The aadA were the second most abundant cassettes and their prevalence was: - aadA1(25%), aadA2(21%), and aadA5(14%). Other cassettes occurred in lower prevalence of below 5%. Prevalence of Tn21, ISEcp1, ISCR1 and IS26 was 22%, 10%, 15%, and 7% respectively. Majority of Tn21 containing integrons carried a complete set of transposition genes while class 2 integrons were borne on Tn7 transposon. The qnrA genes were detected in 34(3%) isolates while 19(1%) carried qnrB. All qnr genes were in MDR strains carrying integrons containing the ISCR1. Close to 88% of bla(TEM-52) were linked to IS26 while ≥ 80% of bla(CTX-Ms) and bla(CMYs) were linked to ISEcp1. Only a few studies have identified a bla(CTX-M-9) containing an ISEcp1 element as reported in this study. Multiple genetic elements, especially those borne on incIl, incFII, and incL/M plasmids, and their associated resistance genes were transferrable en bloc to E. coli strain J53 in mating experiments. CONCLUSIONS: This is the first detailed study on the prevalence of selected elements implicated in evolution of resistance determinants in a large collection of clinical E. coli in Africa. Proliferation of such strains carrying multiple resistance elements is likely to compromise the use of affordable and available treatment options for majority of poor patients in Africa. There is therefore a need to monitor the spread of these highly resistant strains in developing countries through proper infection control and appropriate use of antimicrobials.


Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli/genética , Sequências Repetitivas Dispersas , Farmacorresistência Bacteriana Múltipla , Escherichia coli/efeitos dos fármacos , Escherichia coli/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Humanos , Quênia/epidemiologia , Prevalência
14.
BMC Microbiol ; 12: 155, 2012 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-22838634

RESUMO

BACKGROUND: Although ß-lactam antibiotics are heavily used in many developing countries, the diversity of ß-lactamase genes (bla) is poorly understood. We screened for major ß-lactamase phenotypes and diversity of bla genes among 912 E. coli strains isolated from clinical samples obtained between 1992 and 2010 from hospitalized and non-hospitalized patients. RESULTS: None of the isolates was resistant to carbapenems but 30% of all isolates were susceptible to cefepime, cephamycins and piperacillin-tazobactam. Narrow spectrum ß-lactamase (NSBL) phenotype was observed in 278 (30%) isolates that contained bla(TEM-1) (54%) or bla(SHV-1) (35%) or both (11%). Extended Spectrum ß-lactamase (ESBL) phenotype was detected in 247 (27%) isolates which carried blaCTX-M-14 (29%), bla(CTX-M-15) (24%), bla(CTX-M-9) (2%), bla(CTX-M-8) (4%), bla(CTX-M-3) (11%), bla(CTX-M-1) (6%), blaSHV-5 (3%), bla(SHV-12) (5%), and bla(TEM-52) (16%). Complex Mutant TEM-like (CMT) phenotype was detected in 220 (24%) isolates which carried bla(TEM-125) (29%), while bla(TEM-50), bla(TEM-78), bla(TEM-109), bla(TEM -152) and bla(TEM-158) were detected in lower frequencies of between 7% and 11%. Majority of isolates producing a combination of CTX-M-15 + OXA-1 + TEM-1 exhibited resistance phenotypes barely indistinguishable from those of CMT-producers. Although 73 (8%) isolates exhibited Inhibitor Resistant TEM-like (IRT) phenotype, bla(TEM-103) was the only true IRT-encoding gene identified in 18 (25%) of strains with this phenotype while the rest produced a combination of TEM-1 + OXA-1. The pAmpCs-like phenotype was observed in 94 (10%) isolates of which 77 (82%) carried bla(CMY-2) while 18% contained blaCMY-1.Isolates from urine accounted for 53%, 53%, 74% and 72% of strains exhibiting complex phenotypes such as IRT, ESBL, CMT or pAmpC respectively. On the contrary, 55% isolates from stool exhibited the relatively more susceptible NSBL-like phenotype. All the phenotypes, and majority of the bla genes, were detected both in isolates from hospitalized and non-hospitalized patients but complex phenotypes were particularly common among strains obtained between 2000 and 2010 from urine of hospitalized patients. CONCLUSIONS: The phenotypes and diversity of bla genes in E. coli strains implicated in clinical infections in non-hospitalized and hospitalized patients in Kenya is worryingly high. In order to preserve the efficacy of ß-lactam antibiotics, culture and susceptibility data should guide therapy and surveillance studies for ß-lactamase-producers in developing countries should be launched.


Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli/enzimologia , Escherichia coli/isolamento & purificação , Resistência beta-Lactâmica , beta-Lactamases/genética , beta-Lactamases/metabolismo , Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Infecções por Escherichia coli/epidemiologia , Genótipo , Humanos , Quênia/epidemiologia , Testes de Sensibilidade Microbiana , Fenótipo , Prevalência , beta-Lactamas/farmacologia
17.
J Clin Microbiol ; 48(6): 2171-6, 2010 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20392916

RESUMO

In sub-Saharan Africa, the burden of typhoid fever, caused by Salmonella enterica serovar Typhi, remains largely unknown, in part because of a lack of blood or bone marrow culture facilities. We characterized a total of 323 S. Typhi isolates from outbreaks in Kenya over the period 1988 to 2008 for antimicrobial susceptibilities and phylogenetic relationships using single-nucleotide polymorphism (SNP) analysis. There was a dramatic increase in the number and percentage of multidrug-resistant (MDR) S. Typhi isolates over the study period. Overall, only 54 (16.7%) S. Typhi isolates were fully sensitive, while the majority, 195 (60.4%), were multiply resistant to most commonly available drugs-ampicillin, chloramphenicol, tetracycline, and cotrimoxazole; 74 (22.9%) isolates were resistant to a single antimicrobial, usually ampicillin, cotrimoxazole, or tetracycline. Resistance to these antibiotics was encoded on self-transferrable IncHI1 plasmids of the ST6 sequence type. Of the 94 representative S. Typhi isolates selected for genome-wide haplotype analysis, sensitive isolates fell into several phylogenetically different groups, whereas MDR isolates all belonged to a single haplotype, H58, associated with MDR and decreased ciprofloxacin susceptibility, which is also dominant in many parts of Southeast Asia. Derivatives of the same S. Typhi lineage, H58, are responsible for multidrug resistance in Kenya and parts of Southeast Asia, suggesting intercontinental spread of a single MDR clone. Given the emergence of this aggressive MDR haplotype, careful selection and monitoring of antibiotic usage will be required in Kenya, and potentially other regions of sub-Saharan Africa.


Assuntos
Antibacterianos/farmacologia , Técnicas de Tipagem Bacteriana , Farmacorresistência Bacteriana Múltipla , Salmonella typhi/classificação , Salmonella typhi/efeitos dos fármacos , Febre Tifoide/epidemiologia , Febre Tifoide/microbiologia , Adulto , Ásia Sudeste/epidemiologia , Criança , Pré-Escolar , Análise por Conglomerados , Genes Bacterianos , Genótipo , Haplótipos , Humanos , Quênia/epidemiologia , Filogenia , Plasmídeos/análise , Polimorfismo de Nucleotídeo Único , Salmonella typhi/genética , Salmonella typhi/isolamento & purificação
18.
BMC Microbiol ; 9: 275, 2009 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-20040104

RESUMO

BACKGROUND: Over the last decade, cholera outbreaks in parts of Kenya have become common. Although a number of recent studies describe the epidemiology of cholera in Kenya, there is paucity of information concerning the diversity and occurrence of mobile genetic elements in Vibrio cholerae strains implicated in these outbreaks. A total of 65 Vibrio cholerae O1 El Tor serotype Inaba isolated between 1994 and 2007 from various outbreaks in Kenya were investigated for mobile genetic elements including integrons, transposons, the integrating conjugative elements (ICEs), conjugative plasmids and for their genotypic relatedness. RESULTS: All the strains were haemolytic on 5% sheep blood and positive for the Vibrio cholerae El Tor-specific haemolysin toxin gene (hylA) by PCR. They all contained strB, sulII, floR and the dfrA1 genes encoding resistance to streptomycin, sulfamethoxazole, chloramphenicol and trimethoprim respectively. These genes, together with an ICE belonging to the SXT/R391 family were transferable to the rifampicin-resistant E. coli C600 en bloc. All the strains were negative for integron class 1, 2 and 3 and for transposase gene of transposon Tn7 but were positive for integron class 4 and the trpM gene of transposon Tn21. No plasmids were isolated from any of the 65 strains. All the strains were also positive for all V. cholera El Tor pathogenic genes except the NAG- specific heat-stable toxin (st) gene. None of the strains were positive for virulence genes associated with the V. cholerae classical biotype. All the strains were positive for El Tor-specific CTXphi bacteriophage rstrR repressor gene (CTXETPhi) but negative for the Classical, Calcutta, and the Environmental repressor types. Pulse Field Gel Electrophoresis (PFGE) showed that regardless of the year of isolation, all the strains bearing the SXT element were clonally related. CONCLUSIONS: This study demonstrates that the V. cholerae O1 strains carrying an SXT/R391-like element implicated in recent cholera outbreaks in Kenya has not changed significantly between 1994 and 2007 and are clonally related.


Assuntos
Cólera/microbiologia , Elementos de DNA Transponíveis , Integrons , Plasmídeos , Vibrio cholerae O1/genética , Técnicas de Tipagem Bacteriana , Cólera/epidemiologia , Conjugação Genética , DNA Bacteriano/genética , Surtos de Doenças , Ilhas Genômicas , Genótipo , Humanos , Quênia/epidemiologia , Testes de Sensibilidade Microbiana , Vibrio cholerae O1/classificação , Vibrio cholerae O1/isolamento & purificação , Fatores de Virulência/genética
19.
J Infect Dev Ctries ; 1(3): 257-62, 2007 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-19734602

RESUMO

BACKGROUND: Uropathogenic Escherichia coli are increasingly becoming resistant to flouroquinolones and to other commonly available antimicrobials. We sought to investigate the genetic basis for fluoroquinolone and extended spectrum beta-lactam (ESBL) resistance in 17 fluoroquinolone-resistant (MIC of levofloxacin and ciprofloxacin >32 microg/ml) E. coli isolated from patients with urinary tract infections (UTIs). METHODS: We applied PCR and Pulsed Field Gel Electrophoresis (PFGE) to characterize resistance genes and to determine clonal relatedness of strains, respectively. RESULTS: Twelve of the 17 E. coli were resistant to multiple drugs, including ampicillin, co-amoxyclav, cefotaxime, ceftriaxone, ceftazidime and gentamicin and nalidixic acid and produced plasmid-mediated CTX-M-15 type ESBLs and CMY-2 AmpC type enzymes. The other 5 E. coli that were non-ESBL-producing were multiply resistant to ampicillin, nitrofurantoin, cefoxitin, nalidixic acid. Resistance to fluoroquinolones resulted from a combination of the presence of qnrA, qnrB, ciprofloxacin acetylating enzyme designated aac(6')-1b-cr, and mutations in the two amino acid substitutions; 83 Serine (TCG) to Leucine (TTG) and 87 Aspartic acid (GAC) to Asparagine (AAC). CONCLUSION: Antibiogram patterns and PFGE of E. coli showed that these were community acquired UTI caused by pockets of clonally-related and some discreet strain types. Plasmid-mediated CTX-M-15 beta-lactamases and CMY-2 AmpC enzymes and fluoroquinolone resistant E. coli are becoming increasingly prevalent in hospitals in Kenya, posing a major challenge in the management of UTIs.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Infecções por Escherichia coli/microbiologia , Escherichia coli/efeitos dos fármacos , Fluoroquinolonas/farmacologia , Infecções Urinárias/microbiologia , Resistência beta-Lactâmica/genética , Adolescente , Adulto , Infecções Comunitárias Adquiridas/tratamento farmacológico , Infecções Comunitárias Adquiridas/microbiologia , Eletroforese em Gel de Campo Pulsado , Escherichia coli/enzimologia , Escherichia coli/genética , Infecções por Escherichia coli/tratamento farmacológico , Feminino , Fluoroquinolonas/metabolismo , Humanos , Lactente , Quênia , Masculino , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Infecções Urinárias/tratamento farmacológico , beta-Lactamases/genética
20.
BMC Microbiol ; 6: 101, 2006 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-17173674

RESUMO

BACKGROUND: In sub-Saharan Africa community-acquired non-typhoidal Salmonella (NTS) is a major cause of high morbidity and death among children under 5 years of age especially from resource poor settings. The emergence of multidrug resistance is a major challenge in treatment of life threatening invasive NTS infections in these settings. RESULTS: Overall 170 (51.2%) of children presented with bacteraemia alone, 28 (8.4%) with gastroenteritis and bacteraemia and 134 (40.4%) with gastroenteritis alone. NTS serotypes obtained from all the cases included S. Typhimurium (196; 59%), S. Enteritidis (94; 28.3%) and other serotypes in smaller numbers (42; 12.7%); distribution of these serotypes among cases with bacteremia or gastroenteritis was not significantly different. A significantly higher proportion of younger children (< 3 years of age) and those from the slums presented with invasive NTS compared to older children and those from upper socio-economic groups (p < 0.001). One hundred and forty-seven (44.3%) NTS were resistant to 3 or more antibiotics, and out of these 59% were resistant to ampicillin, chloramphenicol and tetracycline. There was no significant difference in antibiotic resistance between the two serotypes, S. Typhimurium and S. Enteritidis. Ceftriaxone and ciprofloxacin were the only antibiotics tested to which all the NTS were fully susceptible. Using Pulsed Field Gel Electrophoresis (PFGE) there were 3 main patterns of S. Typhimurium and 2 main patterns of S. Enteritidis among cases of bacteraemia and gastroenteritis. CONCLUSION: Serotype distribution, antibiotic susceptibility and PFGE patterns of NTS causing bacteraemia and gastroenteritis did not differ significantly. The high prevalence of NTS strains resistant to most of the commonly used antimicrobials is of major public health concern.


Assuntos
Bacteriemia/microbiologia , Infecções Comunitárias Adquiridas/microbiologia , Infecções por Salmonella/microbiologia , Salmonella/classificação , Bacteriemia/epidemiologia , Ceftriaxona/uso terapêutico , Cefuroxima/uso terapêutico , Criança , Pré-Escolar , Infecções Comunitárias Adquiridas/epidemiologia , Diarreia/epidemiologia , Diarreia/microbiologia , Resistência a Medicamentos , Eletroforese em Gel de Campo Pulsado/métodos , Feminino , Hospitalização , Humanos , Lactente , Recém-Nascido , Quênia/epidemiologia , Masculino , Testes de Sensibilidade Microbiana , Estudos Prospectivos , Salmonella/genética , Salmonella/isolamento & purificação , Infecções por Salmonella/epidemiologia , Salmonella enteritidis/efeitos dos fármacos , Salmonella enteritidis/genética , Salmonella enteritidis/isolamento & purificação , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Salmonella typhimurium/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA