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1.
BMC Res Notes ; 17(1): 70, 2024 Mar 12.
Artículo en Inglés | MEDLINE | ID: mdl-38475810

RESUMEN

OBJECTIVE: In this study, we sought to determine the types and prevalence of antimicrobial resistance determinants (ARDs) in Burkholderia spp. strains using the Antimicrobial Resistance Determinant Microarray (ARDM). RESULTS: Whole genome amplicons from 22 B. mallei (BM) and 37 B. pseudomallei (BP) isolates were tested for > 500 ARDs using ARDM v.3.1. ARDM detected the following Burkholderia spp.-derived genes, aac(6), blaBP/MBL-3, blaABPS, penA-BP, and qacE, in both BM and BP while blaBP/MBL-1, macB, blaOXA-42/43 and penA-BC were observed in BP only. The method of denaturing template for whole genome amplification greatly affected the numbers and types of genes detected by the ARDM. BlaTEM was detected in nearly a third of BM and BP amplicons derived from thermally, but not chemically denatured templates. BlaTEM results were confirmed by PCR, with 81% concordance between methods. Sequences from 414-nt PCR amplicons (13 preparations) were 100% identical to the Klebsiella pneumoniae reference gene. Although blaTEM sequences have been observed in B. glumae, B. cepacia, and other undefined Burkholderia strains, this is the first report of such sequences in BM/BP/B. thailandensis (BT) clade. These results highlight the importance of sample preparation in achieving adequate genome coverage in methods requiring untargeted amplification before analysis.


Asunto(s)
Antiinfecciosos , Burkholderia mallei , Burkholderia pseudomallei , Burkholderia , Síndrome de Dificultad Respiratoria , Humanos , Burkholderia mallei/genética , Burkholderia/genética
2.
Front Microbiol ; 13: 1059695, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36532481

RESUMEN

Introduction: In spite of promising medical, sociological, and engineering strategies and interventions to reduce the burden of disease, malaria remains a source of significant morbidity and mortality, especially among children in sub-Saharan Africa. In particular, progress in the development and administration of chemotherapeutic agents is threatened by evolved resistance to most of the antimalarials currently in use, including artemisinins. Methods: This study analyzed the prevalence of mutations associated with antimalarial resistance in Plasmodium falciparum from 95 clinical samples collected from individuals with clinically confirmed malaria at a hospital in Bo, Sierra Leone between May 2017 and December 2018. The combination of polymerase chain reaction amplification and subsequent high throughput DNA sequencing was used to determine the presence of resistance-associated mutations in five P. falciparum genes - pfcrt, pfmdr1, pfdhfr, pfdhps and pfkelch13. The geographic origin of parasites was assigned using mitochondrial sequences. Results: Relevant mutations were detected in the pfcrt (22%), pfmdr1 (>58%), pfdhfr (100%) and pfdhps (>80%) genes while no resistance-associated mutations were found in the pfkelch13 gene. The mitochondrial barcodes were consistent with a West African parasite origin with one exception indicating an isolate imported from East Africa. Discussion: Detection of the pfmdr1 NFSND haplotype in 50% of the samples indicated the increasing prevalence of strains with elevated tolerance to artemeter + lumefantrine (AL) threatening the combination currently used to treat uncomplicated malaria in Sierra Leone. The frequency of mutations linked to resistance to antifolates suggests widespread resistance to the drug combination used for intermittent preventive treatment during pregnancy.

3.
Malar J ; 20(1): 133, 2021 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-33676502

RESUMEN

BACKGROUND: Rapid and sensitive diagnostics are critical tools for clinical case management and public health control efforts. Both capillary and venous blood are currently used for malaria detection and while diagnostic technologies may not be equally sensitive with both materials, the published data on this subject are scarce and not conclusive. METHODS: Paired clinical samples of venous and capillary blood from 141 febrile individuals in Bo, Sierra Leone, were obtained between January and May 2019 and tested for the presence of Plasmodium parasites using two multiplexed PCR assays: the FilmArray-based Global Fever Panel (GFP) and the TaqMan-based Malaria Multiplex Sample Ready (MMSR) assay. RESULTS: No significant differences in Plasmodium parasite detection between capillary and venous blood for both assays were observed. The GFP assay was more sensitive than MMSR for all markers that could be compared (Plasmodium spp. and Plasmodium falciparum) in both venous and capillary blood. CONCLUSIONS: No difference was found in malaria detection between venous and capillary blood using two different PCR-based detection assays. This data gives support for use of capillary blood, a material which can be obtained easier by less invasive methods, for PCR-based malaria diagnostics, independent of the platform.


Asunto(s)
Capilares/parasitología , Pruebas Diagnósticas de Rutina/estadística & datos numéricos , Malaria/diagnóstico , Reacción en Cadena de la Polimerasa Multiplex/estadística & datos numéricos , Plasmodium/aislamiento & purificación , Venas/parasitología , Adolescente , Adulto , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad , Sierra Leona , Especificidad de la Especie , Adulto Joven
4.
Int J Mol Sci ; 21(16)2020 Aug 18.
Artículo en Inglés | MEDLINE | ID: mdl-32824772

RESUMEN

Infectious diarrhea affects over four billion individuals annually and causes over a million deaths each year. Though not typically prescribed for treatment of uncomplicated diarrheal disease, antimicrobials serve as a critical part of the armamentarium used to treat severe or persistent cases. Due to widespread over- and misuse of antimicrobials, there has been an alarming increase in global resistance, for which a standardized methodology for geographic surveillance would be highly beneficial. To demonstrate that a standardized methodology could be used to provide molecular surveillance of antimicrobial resistance (AMR) genes, we initiated a pilot study to test 130 diarrheal pathogens (Campylobacter spp., Escherichia coli, Salmonella, and Shigella spp.) from the USA, Peru, Egypt, Cambodia, and Kenya for the presence/absence of over 200 AMR determinants. We detected a total of 55 different determinants conferring resistance to ten different categories of antimicrobials: genes detected in ≥ 25 samples included blaTEM, tet(A), tet(B), mac(A), mac(B), aadA1/A2, strA, strB, sul1, sul2, qacEΔ1, cmr, and dfrA1. The number of determinants per strain ranged from none (several Campylobacter spp. strains) to sixteen, with isolates from Egypt harboring a wider variety and greater number of genes per isolate than other sites. Two samples harbored carbapenemase genes, blaOXA-48 or blaNDM. Genes conferring resistance to azithromycin (ere(A), mph(A)/mph(K), erm(B)), a first-line therapeutic for severe diarrhea, were detected in over 10% of all Enterobacteriaceae tested: these included >25% of the Enterobacteriaceae from Egypt and Kenya. Forty-six percent of the Egyptian Enterobacteriaceae harbored genes encoding CTX-M-1 or CTX-M-9 families of extended-spectrum ß-lactamases. Overall, the data provide cross-comparable resistome information to establish regional trends in support of international surveillance activities and potentially guide geospatially informed medical care.


Asunto(s)
Campylobacter/genética , Diarrea/microbiología , Farmacorresistencia Microbiana , Escherichia coli Enteropatógena/genética , Genes Bacterianos , Salmonella/genética , Shigella/genética , Antibacterianos/toxicidad , Campylobacter/efectos de los fármacos , Campylobacter/aislamiento & purificación , Campylobacter/patogenicidad , Diarrea/epidemiología , Escherichia coli Enteropatógena/efectos de los fármacos , Escherichia coli Enteropatógena/aislamiento & purificación , Escherichia coli Enteropatógena/patogenicidad , Humanos , Salmonella/efectos de los fármacos , Salmonella/aislamiento & purificación , Salmonella/patogenicidad , Shigella/efectos de los fármacos , Shigella/aislamiento & purificación , Shigella/patogenicidad
5.
Int J Mol Sci ; 21(5)2020 Feb 29.
Artículo en Inglés | MEDLINE | ID: mdl-32121349

RESUMEN

A dramatic increase in global antimicrobial resistance (AMR) has been well documented. Of particular concern is the dearth of information regarding the spectrum and prevalence of AMR within Category A Select Agents. Here, we performed a survey of horizontally and vertically transferred AMR determinants among Category A agents and their near neighbors. Microarrays provided broad spectrum screening of 127 Francisella spp., Yersinia spp., and Bacillus spp. strains for the presence/absence of 500+ AMR genes (or families of genes). Detecting a broad variety of AMR genes in each genus, microarray analysis also picked up the presence of an engineered plasmid in a Y. pestis strain. High resolution melt analysis (HRMA) was also used to assess the presence of quinolone resistance-associated mutations in 100 of these strains. Though HRMA was able to detect resistance-causing point mutations in B. anthracis strains, it was not capable of discriminating these point mutations from other nucleotide substitutions (e.g., arising from sequence differences in near neighbors). Though these technologies are well-established, to our knowledge, this is the largest survey of Category A agents and their near-neighbor species for genes covering multiple mechanisms of AMR.


Asunto(s)
Infecciones Bacterianas/genética , Farmacorresistencia Bacteriana/genética , Quinolonas/uso terapéutico , Bacillus/efectos de los fármacos , Bacillus/genética , Bacillus/patogenicidad , Infecciones Bacterianas/tratamiento farmacológico , Infecciones Bacterianas/microbiología , Francisella/efectos de los fármacos , Francisella/genética , Francisella/patogenicidad , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Humanos , Mutación/genética , Plásmidos/genética , Yersinia/efectos de los fármacos , Yersinia/genética , Yersinia/patogenicidad
6.
Malar J ; 19(1): 84, 2020 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-32085711

RESUMEN

BACKGROUND: Malaria continues to affect over 200 million individuals every year, especially children in Africa. Rapid and sensitive detection and identification of Plasmodium parasites is crucial for treating patients and monitoring of control efforts. Compared to traditional diagnostic methods such as microscopy and rapid diagnostic tests (RDTs), DNA based methods, such as polymerase chain reaction (PCR) offer significantly higher sensitivity, definitive discrimination of Plasmodium species, and detection of mixed infections. While PCR is not currently optimized for routine diagnostics, its role in epidemiological studies is increasing as the world moves closer toward regional and eventually global malaria elimination. This study demonstrates the field use of a novel, ambient temperature-stabilized, multiplexed PCR assay in a small hospital setting in Sierra Leone. METHODS: Blood samples from 534 febrile individuals reporting to a hospital in Bo, Sierra Leone, were tested using three methods: a commercial RDT, microscopy, and a Multiplex Malaria Sample Ready (MMSR) PCR designed to detect a universal malaria marker and species-specific markers for Plasmodium falciparum and Plasmodium vivax. A separate PCR assay was used to identify species of Plasmodium in samples in which MMSR detected malaria, but was unable to identify the species. RESULTS: MMSR detected the presence of any malaria marker in 50.2% of all tested samples with P. falciparum identified in 48.7% of the samples. Plasmodium vivax was not detected. Testing of MMSR P. falciparum-negative/universal malaria-positive specimens with a panel of species-specific PCRs revealed the presence of Plasmodium malariae (n = 2) and Plasmodium ovale (n = 2). The commercial RDT detected P. falciparum in 24.6% of all samples while microscopy was able to detect malaria in 12.8% of tested specimens. CONCLUSIONS: Wider application of PCR for detection of malaria parasites may help to fill gaps existing as a result of use of microscopy and RDTs. Due to its high sensitivity and specificity, species coverage, room temperature stability and relative low complexity, the MMSR assay may be useful for detection of malaria and epidemiological studies especially in low-resource settings.


Asunto(s)
Malaria/epidemiología , Reacción en Cadena de la Polimerasa Multiplex/métodos , Plasmodium/aislamiento & purificación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Adolescente , Adulto , Niño , Preescolar , Pruebas Diagnósticas de Rutina , Femenino , Humanos , Masculino , Microscopía , Persona de Mediana Edad , Prevalencia , Sensibilidad y Especificidad , Sierra Leona/epidemiología , Adulto Joven
7.
Anal Biochem ; 585: 113405, 2019 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-31445900

RESUMEN

Microarrays are a valuable tool for analysis of both bacterial and eukaryotic nucleic acids. As many of these applications use non-specific amplification to increase sample concentration prior to analysis, the methods used to fragment and label large amplicons are important to achieve the desired analytical selectivity and specificity. Here, we used eight sequenced ESKAPE pathogens to determine the effect of two methods of whole genome amplicon fragmentation and three methods of subsequent labeling on microarray performance; nick translation was also assessed. End labeling of both initial DNase I-treated and sonication-fragmented amplicons failed to provide detectable material for a significant number of sequence-confirmed genes. However, processing of amplicons by nick translation, or by sequential fragmentation and labeling by Universal Labeling System or Klenow fragment/random primer provided good sensitivity and selectivity, with marginally better results obtained by Klenow fragment labeling. Nick-translation provided 91-100% sensitivity and 100% specificity in the tested strains, requiring half as many manipulations and less than 4h to process samples for hybridization; full sample processing from whole genome amplification to final data analysis could be performed in less than 10h. The method of template denaturation before amplification did affect detection sensitivity/selectivity of nick-labeled amplicons, however.


Asunto(s)
Bacterias/genética , ADN Bacteriano/análisis , Técnicas de Amplificación de Ácido Nucleico/métodos , Técnicas Biosensibles , Desoxirribonucleasa I/metabolismo , Hibridación de Ácido Nucleico , Análisis de Secuencia por Matrices de Oligonucleótidos , Sensibilidad y Especificidad , Coloración y Etiquetado
8.
BMC Res Notes ; 11(1): 113, 2018 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-29422083

RESUMEN

OBJECTIVE: The aim of this study was to determine the prevalence of hepatitis B surface antigen (HBsAg) among febrile individuals tested at Mercy Hospital Research Laboratory (MHRL) in Bo, Sierra Leone. RESULTS: A total of 860 febrile individuals ages 5 years and older were tested by MHRL between July 2012 and June 2013 with a Standard Diagnostics Bioline HBsAg rapid diagnostic test. The overall HBsAg prevalence rate was 13.7%, including a rate of 15.5% among males and 12.6% among females. The HBsAg rate did not differ by child or adult age group (p > 0.5). The prevalence rate in Bo was similar to the 11-15% HBsAg prevalence rates reported in the past decade from other studies across West Africa. Scaling up the infant hepatitis B vaccination program in Sierra Leone will be important for reducing the future burden of disease and premature death attributable to chronic viral hepatitis B disease.


Asunto(s)
Fiebre/sangre , Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B Crónica/prevención & control , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Seroepidemiológicos , Sierra Leona/epidemiología , Adulto Joven
9.
BMC Res Notes ; 10(1): 565, 2017 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-29110721

RESUMEN

OBJECTIVE: The goal of this study was to examine the prevalence of HIV among febrile patients seeking care in Mercy Hospital, Bo, Sierra Leone, in 2012-2013. RESULTS: A total of 1207 febrile persons were tested for HIV with Determine™ and SD Bioline rapid diagnostic tests kits that detect the presence of HIV antibodies and HIV p24 antigens. The overall prevalence of HIV among the tested patients was 8.9%, which is considerably higher than the < 2% prevalence of HIV reported previously in the general population. While these results are not sufficient to prove a causal relationship, the obtained data imply that HIV positive individuals may be more likely to suffer from febrile infectious diseases than individuals without HIV infection. Increasing the availability and use of HIV testing services will allow antiretroviral therapy to be accessed in a timely manner and improve health status among people living with HIV.


Asunto(s)
Biomarcadores/sangre , Fiebre/sangre , Fiebre/complicaciones , Infecciones por VIH/sangre , Infecciones por VIH/complicaciones , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Sierra Leona , Adulto Joven
10.
Am J Trop Med Hyg ; 97(4): 1151-1154, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-29031286

RESUMEN

Malaria remains a significant cause of morbidity and mortality in West Africa, but the contribution of other vector-borne infections (VBIs) to the burden of disease has been understudied. We used rapid diagnostic tests (RDTs) for three VBIs to test blood samples from 1,795 febrile residents of Bo City, Sierra Leone, over a 1-year period in 2012-2013. In total, 24% of the tests were positive for malaria, fewer than 5% were positive for markers of dengue virus infection, and 39% were positive for IgM directed against chikungunya virus (CHIKV) or a related alphavirus. In total, more than half (55%) of these febrile individuals tested positive for at least one of the three VBIs, which highlights the very high burden of vector-borne diseases in this population. The prevalence of positives on the Chikungunya IgM and dengue tests did not vary significantly with age (P > 0.36), but higher rates of malaria were observed in children < 15 years of age (P < 0.001). Positive results on the Chikungunya IgM RDTs were moderately correlated with rainfall (r2 = 0.599). Based on the high prevalence of positive results on the Chikungunya IgM RDTs from individuals Bo and its environs, there is a need to examine whether an ecological shift toward a greater burden from CHIKV or related alphaviruses is occurring in other parts of Sierra Leone or the West African region.


Asunto(s)
Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Malaria/epidemiología , Vigilancia de la Población , Adolescente , Adulto , Animales , Fiebre Chikungunya/transmisión , Niño , Culicidae , Dengue/transmisión , Femenino , Humanos , Insectos Vectores , Malaria/transmisión , Masculino , Persona de Mediana Edad , Sierra Leona/epidemiología , Adulto Joven
11.
Anal Chem ; 89(19): 10296-10302, 2017 10 03.
Artículo en Inglés | MEDLINE | ID: mdl-28876903

RESUMEN

Understanding the interaction between macrophage cells and Bacillus anthracis spores is of significant importance with respect to both anthrax disease progression, spore detection for biodefense, as well as understanding cell clearance in general. While most detection systems rely on specific molecules, such as nucleic acids or proteins and fluorescent labels to identify the target(s) of interest, label-free methods probe changes in intrinsic properties, such as size, refractive index, and morphology, for correlation with a particular biological event. Optical chromatography is a label free technique that uses the balance between optical and fluidic drag forces within a microfluidic channel to determine the optical force on cells or particles. Here we show an increase in the optical force experienced by RAW264.7 macrophage cells upon the uptake of both microparticles and B. anthracis Sterne 34F2 spores. In the case of spores, the exposure was detected in as little as 1 h without the use of antibodies or fluorescent labels of any kind. An increase in the optical force was also seen in macrophage cells treated with cytochalasin D, both with and without a subsequent exposure to spores, indicating that a portion of the increase in the optical force arises independent of phagocytosis. These results demonstrate the capability of optical chromatography to detect subtle biological differences in a rapid and sensitive manner and suggest future potential in a range of applications, including the detection of biological threat agents for biodefense and pathogens for the prevention of sepsis and other diseases.


Asunto(s)
Bacillus anthracis/fisiología , Óptica y Fotónica/métodos , Esporas Bacterianas/metabolismo , Animales , Citocalasina D/metabolismo , Dispositivos Laboratorio en un Chip , Rayos Láser , Proteínas Luminiscentes/genética , Proteínas Luminiscentes/metabolismo , Macrófagos/citología , Macrófagos/metabolismo , Macrófagos/microbiología , Ratones , Microscopía Confocal , Fagocitosis , Células RAW 264.7 , Esporas Bacterianas/inmunología , Proteína Fluorescente Roja
12.
PLoS One ; 12(6): e0178880, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28575064

RESUMEN

We sought to determine the genetic and phenotypic antimicrobial resistance (AMR) profiles of commensal Klebsiella spp. circulating in Kenya by testing human stool isolates of 87 K. pneumoniae and three K. oxytoca collected at eight locations. Over one-third of the isolates were resistant to ≥3 categories of antimicrobials and were considered multidrug-resistant (MDR). We then compared the resistance phenotype to the presence/absence of 238 AMR genes determined by a broad-spectrum microarray and PCR. Forty-six genes/gene families were identified conferring resistance to ß-lactams (ampC/blaDHA, blaCMY/LAT, blaLEN-1, blaOKP-A/OKP-B1, blaOXA-1-like family, blaOXY-1, blaSHV, blaTEM, blaCTX-M-1 and blaCTX-M-2 families), aminoglycosides (aac(3)-III, aac(6)-Ib, aad(A1/A2), aad(A4), aph(AI), aph3/str(A), aph6/str(B), and rmtB), macrolides (mac(A), mac(B), mph(A)/mph(K)), tetracyclines (tet(A), tet(B), tet(D), tet(G)), ansamycins (arr), phenicols (catA1/cat4, floR, cmlA, cmr), fluoroquinolones (qnrS), quaternary amines (qacEΔ1), streptothricin (sat2), sulfonamides (sul1, sul2, sul3), and diaminopyrimidines (dfrA1, dfrA5, dfrA7, dfrA8, dfrA12, dfrA13/21/22/23 family, dfrA14, dfrA15, dfrA16, dfrA17). This is the first profile of genes conferring resistance to multiple categories of antimicrobial agents in western and central Kenya. The large number and wide variety of resistance genes detected suggest the presence of significant selective pressure. The presence of five or more resistance determinants in almost two-thirds of the isolates points to the need for more effective, targeted public health policies and infection control/prevention measures.


Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Heces/microbiología , Infecciones por Klebsiella/tratamiento farmacológico , Infecciones por Klebsiella/microbiología , Klebsiella pneumoniae/efectos de los fármacos , Klebsiella pneumoniae/aislamiento & purificación , Adolescente , Adulto , Niño , Preescolar , Femenino , Genes Bacterianos , Humanos , Lactante , Kenia/epidemiología , Infecciones por Klebsiella/epidemiología , Klebsiella pneumoniae/genética , Masculino , Persona de Mediana Edad , Adulto Joven
13.
Genome Announc ; 4(6)2016 Nov 03.
Artículo en Inglés | MEDLINE | ID: mdl-27811104

RESUMEN

Citrobacter freundii is a Gram-negative opportunistic pathogen that is increasingly being recognized as a causative agent of hospital-acquired urinary tract infections and an important reservoir of antimicrobial resistance determinants. In this report, we describe the finished genome sequence of C. freundii strain SL151, a highly multidrug-resistant human urine isolate.

14.
Antimicrob Agents Chemother ; 60(11): 6920-6923, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-27572395

RESUMEN

A collection of 74 Enterobacteriaceae isolates found in Bo, Sierra Leone, were tested for quinolone antibiotic susceptibility and resistance mechanisms. The majority of isolates (62%) were resistant to quinolones, and 61% harbored chromosomal gyrA and/or parC mutations. Plasmid-mediated quinolone resistance genes were ubiquitous, with qnrB and aac(6')-Ib-cr being the most prevalent. Mutated LexA binding sites were found in all qnrB1 genes, and truncated qnrB pseudogenes were found in the majority of Citrobacter isolates.


Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana/genética , Enterobacteriaceae/efectos de los fármacos , Quinolonas/farmacología , Serina Endopeptidasas/metabolismo , Proteínas Bacterianas/genética , Sitios de Unión , Girasa de ADN/genética , Topoisomerasa de ADN IV/genética , Farmacorresistencia Bacteriana/efectos de los fármacos , Enterobacteriaceae/genética , Enterobacteriaceae/aislamiento & purificación , Infecciones por Enterobacteriaceae/epidemiología , Infecciones por Enterobacteriaceae/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Mutación , Seudogenes , Sierra Leona/epidemiología
15.
BMC Infect Dis ; 16: 167, 2016 Apr 18.
Artículo en Inglés | MEDLINE | ID: mdl-27090787

RESUMEN

BACKGROUND: The rising level of antimicrobial resistance among bacterial pathogens is one of the most significant public health problems globally. While the antibiotic resistance of clinically important bacteria is closely tracked in many developed countries, the types and levels of resistance and multidrug resistance (MDR) among pathogens currently circulating in most countries of sub-Saharan Africa are virtually unknown. METHODS: From December 2013 to April 2014, we collected 93 urine specimens from all outpatients showing symptoms of urinary tract infection (UTI) and 189 fomite swabs from a small hospital in Bo, Sierra Leone. Culture on chromogenic agar combined with biochemical and DNA sequence-based assays was used to detect and identify the bacterial isolates. Their antimicrobial susceptibilities were determined using a panel of 11 antibiotics or antibiotic combinations. RESULTS: The 70 Enterobacteriaceae urine isolates were identified as Citrobacter freundii (n = 22), Klebsiella pneumoniae (n = 15), Enterobacter cloacae (n = 15), Escherichia coli (n = 13), Enterobacter sp./Leclercia sp. (n = 4) and Escherichia hermannii (n = 1). Antimicrobial susceptibility testing demonstrated that 85.7 % of these isolates were MDR while 64.3 % produced an extended-spectrum ß-lactamase (ESBL). The most notable observations included widespread resistance to sulphonamides (91.4 %), chloramphenicol (72.9 %), gentamycin (72.9 %), ampicillin with sulbactam (51.4 %) and ciprofloxacin (47.1 %) with C. freundii exhibiting the highest and E. coli the lowest prevalence of multidrug resistance. The environmental cultures resulted in only five Enterobacteriaceae isolates out of 189 collected with lower overall antibiotic resistance. CONCLUSIONS: The surprisingly high proportion of C. freundii found in urine of patients with suspected UTI supports earlier findings of the growing role of this pathogen in UTIs in low-resource countries. The isolates of all analyzed species showed worryingly high levels of resistance to both first- and second-line antibiotics as well as a high frequency of MDR and ESBL phenotypes, which likely resulted from the lack of consistent antibiotic stewardship policies in Sierra Leone. Analysis of hospital environmental isolates however suggested that fomites in this naturally ventilated hospital were not a major reservoir for Enterobacteriaceae or antibiotic resistance determinants.


Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Enterobacteriaceae/efectos de los fármacos , Adulto , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Bacteriano/metabolismo , Enterobacteriaceae/genética , Enterobacteriaceae/aislamiento & purificación , Femenino , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Pacientes Ambulatorios , Análisis de Secuencia de ADN , Sierra Leona , Infecciones Urinarias/diagnóstico , Infecciones Urinarias/microbiología , beta-Lactamasas/genética
16.
J Clin Microbiol ; 53(7): 2368-70, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25972415

RESUMEN

Laboratories associated with small hospitals often have limited expertise, personnel, and equipment to rapidly identify rare and emerging infectious diseases. We describe the successful use of the FilmArray system for rapid detection of Ebola virus directly from clinical samples in 6 out of 83 tested subjects in a small health care center in Sierra Leone.


Asunto(s)
Ebolavirus/aislamiento & purificación , Fiebre Hemorrágica Ebola/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Reacción en Cadena de la Polimerasa Multiplex/métodos , Virología/métodos , Sangre/virología , Ebolavirus/genética , Hospitales , Humanos , Faringe/virología , Sierra Leona
17.
Emerg Infect Dis ; 21(4): 609-18, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25811712

RESUMEN

Lassa virus (LASV) is endemic to parts of West Africa and causes highly fatal hemorrhagic fever. The multimammate rat (Mastomys natalensis) is the only known reservoir of LASV. Most human infections result from zoonotic transmission. The very diverse LASV genome has 4 major lineages associated with different geographic locations. We used reverse transcription PCR and resequencing microarrays to detect LASV in 41 of 214 samples from rodents captured at 8 locations in Sierra Leone. Phylogenetic analysis of partial sequences of nucleoprotein (NP), glycoprotein precursor (GPC), and polymerase (L) genes showed 5 separate clades within lineage IV of LASV in this country. The sequence diversity was higher than previously observed; mean diversity was 7.01% for nucleoprotein gene at the nucleotide level. These results may have major implications for designing diagnostic tests and therapeutic agents for LASV infections in Sierra Leone.


Asunto(s)
Variación Genética , Fiebre de Lassa/epidemiología , Fiebre de Lassa/virología , Virus Lassa/clasificación , Virus Lassa/genética , Filogeografía , Animales , Genes Virales , Genoma Viral , Genotipo , Geografía , Fiebre de Lassa/transmisión , Análisis de Secuencia por Matrices de Oligonucleótidos , Filogenia , Ratas , Sierra Leona/epidemiología
18.
J Glob Antimicrob Resist ; 3(3): 198-204, 2015 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27873709

RESUMEN

This study aimed to identify the molecular determinants responsible for antibiotic resistance among human wound isolates in Cambodia. Staphylococcus spp. (n=10) and a variety of Gram-negative isolates (n=21) were taken from a larger collection of wound isolates collected during 2011-2013 and were analysed for the presence of >230 resistance determinants using a broad-spectrum DNA microarray. These isolates were chosen to represent the species most commonly found in wound isolates referred during this time and to include some of the most resistant strains. Resistance determinants detected among the staphylococci included blaZ (90%), mecA (100%), erm(B) (70%), erm(C) (20%), tet(38) (90%), tet(K) (40%), tet(Lp) (10%), tet(M) (20%), lnu(A)/lin(A) and lnu(B)/lin(B) (10% each), msr(A)/msr(B)/msr(SA) (10%), norA (80%) and dfrA (10%). Eleven different ß-lactamase genes were detected among the Gram-negative bacteria, including genes encoding the TEM (48%), CTX-M-1 (48%), CTX-M-9 (5%), SHV (5%) and VEB (10%) families of broad-spectrum and extended-spectrum ß-lactamase enzymes, as well as the carbapenemase gene blaOXA-23. Forty additional genes were also detected in the Gram-negative isolates conferring resistance to aminoglycosides (11 genes), phenicols (5 genes), macrolides [4 genes, including mph(A)/mph(K) (10%)], lincosamides [lnu(F)/lin(F), lnu(G)/lin(G)], tetracycline (4 genes), rifampicin [arr (29%)], quaternary amines [qacEΔ1 (43%)], quinolones [qnrS (14%) and qnrB (5%)], sulfonamides [sul1 (29%), sul2 (38%) and sul3 (10%)], streptothricin (sat2) and trimethoprim (6 genes). The results obtained here provide a snapshot of the broad variety of resistance determinants currently circulating within Cambodia.

20.
Antimicrob Agents Chemother ; 58(2): 767-81, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24247131

RESUMEN

Multidrug-resistant (MDR) Acinetobacter baumannii infections are of particular concern within medical treatment facilities, yet the gene assemblages that give rise to this phenotype remain poorly characterized. In this study, we tested 97 clinical A. baumannii isolates collected from military treatment facilities (MTFs) from 2003 to 2009 by using a molecular epidemiological approach that enabled for the simultaneous screening of 236 antimicrobial resistance genes. Overall, 80% of the isolates were found to be MDR, each strain harbored between one and 17 resistant determinants, and a total of 52 unique resistance determinants or gene families were detected which are known to confer resistance to ß-lactam (e.g., blaGES-11, blaTEM, blaOXA-58), aminoglycoside (e.g., aphA1, aacC1, armA), macrolide (msrA, msrB), tetracycline [e.g., tet(A), tet(B), tet(39)], phenicol (e.g., cmlA4, catA1, cat4), quaternary amine (qacE, qacEΔ1), streptothricin (sat2), sulfonamide (sul1, sul2), and diaminopyrimidine (dfrA1, dfrA7, dfrA19) antimicrobial compounds. Importantly, 91% of the isolates harbored blaOXA-51-like carbapenemase genes (including six new variants), 40% harbored the blaOXA-23 carbapenemase gene, and 89% contained a variety of aminoglycoside resistance determinants with up to six unique determinants identified per strain. Many of the resistance determinants were found in potentially mobile gene cassettes; 45% and 7% of the isolates contained class 1 and class 2 integrons, respectively. Combined, the results demonstrate a facile approach that supports a more complete understanding of the genetic underpinnings of antimicrobial resistance to better assess the load, transmission, and evolution of MDR in MTF-associated A. baumannii.


Asunto(s)
Acinetobacter baumannii/genética , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Genes Bacterianos , Hospitales Militares , beta-Lactamasas/genética , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/microbiología , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Proteínas Bacterianas/metabolismo , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/genética , Expresión Génica , Humanos , Pruebas de Sensibilidad Microbiana , Personal Militar , Anotación de Secuencia Molecular , Familia de Multigenes , Plásmidos , Estados Unidos , beta-Lactamasas/metabolismo
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