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ramR mutations affecting fluoroquinolone susceptibility in epidemic multidrug-resistant Salmonella enterica serovar Kentucky ST198  [PDF]
Etienne Giraud,Axel Cloeckaert
Frontiers in Microbiology , 2013, DOI: 10.3389/fmicb.2013.00213
Abstract: A screening for non-target mutations affecting fluoroquinolone susceptibility was conducted in epidemic multidrug-resistant Salmonella enterica serovar Kentucky ST198. Among a panel of representative isolates (n = 27), covering the epidemic, only three showed distinct mutations in ramR resulting in enhanced expression of genes encoding the AcrAB-TolC efflux system and low increase in ciprofloxacin MIC. No mutations were detected in other regulatory regions of this efflux system. Ciprofloxacin resistance in serovar Kentucky ST198 is thus currently mainly due to multiple target gene mutations.
Detection of mutations in the gyrA of clinical Salmonella spp.
U Govinden, C Mocktar, P Moodley, A.W Sturm, S.Y Essack
African Journal of Biotechnology , 2009,
Abstract: The high prevalence of resistance to nalidixic acid and reduced susceptibility to ciprofloxacin of Salmonella spp. obtained from stool samples of neonates presenting with acute diarrhea in 2001 at the King Edward VIII hospital in Durban, South Africa, prompted this study to determine if there were any mutations in the QRDR of these isolates and to search for the qnrA gene. All isolates with nalidixic acid MICs > 48 μg/ml had the single mutation D87N, or D87G in the QRDR of the gyrA gene, and only 2 strains had an additional mutation; S83L and S83F respectively. The mutation S83T was present in only one isolate with the nalidixic acid MIC of 10 μg/ml whilst the 6 other strains with nalidixic acid MICs < 10 μg/ml had no changes in the QRDR of the gyrA gene. The qnrA gene was not found. These findings indicate that there are mutations in the gyrA of Salmonella isolates which could contribute to resistance to nalidixic acid with reduced susceptibility to ciprofloxacin and there is the co-expression of quinolone and extended-spectrum -lactam resistance among Salmonella spp.
Development of Rapid Detection and Genetic Characterization of Salmonella in Poultry Breeder Feeds  [PDF]
Robin Jarquin,Irene Hanning,Soohyoun Ahn,Steven C. Ricke
Sensors , 2009, DOI: 10.3390/s90705308
Abstract: Salmonella is a leading cause of foodborne illness in the United States, with poultry and poultry products being a primary source of infection to humans. Poultry may carry some Salmonella serovars without any signs or symptoms of disease and without causing any adverse effects to the health of the bird. Salmonella may be introduced to a flock by multiple environmental sources, but poultry feed is suspected to be a leading source. Detecting Salmonella in feed can be challenging because low levels of the bacteria may not be recovered using traditional culturing techniques. Numerous detection methodologies have been examined over the years for quantifying Salmonella in feeds and many have proven to be effective for Salmonella isolation and detection in a variety of feeds. However, given the potential need for increased detection sensitivity, molecular detection technologies may the best candidate for developing rapid sensitive methods for identifying small numbers of Salmonella in the background of large volumes of feed. Several studies have been done using polymerase chain reaction (PCR) assays and commercial kits to detect Salmonella spp. in a wide variety of feed sources. In addition, DNA array technology has recently been utilized to track the dissemination of a specific Salmonella serotype in feed mills. This review will discuss the processing of feeds and potential points in the process that may introduce Salmonella contamination to the feed. Detection methods currently used and the need for advances in these methods also will be discussed. Finally, implementation of rapid detection for optimizing control methods to prevent and remove any Salmonella contamination of feeds will be considered.
J. Boci,P. Cabeli,T. Shtylla
Albanian Journal of Agricultural Sciences , 2011,
Abstract: During 2006 – 2010, out of many poultry farms located in different geographic areas within the country (Fier, Kavaje, Durres, Elbasan, Shkoder, Korce, Lezhe and Lushnje) were championed/selected visceral organs and intestinal materials. In this study, were isolated a total of 1.496 strains of E. coli and Salmonella spp. The findings obtained from this study, provide a clear picture on the presence, distribution and the behavioral of poultry pathogenosity of E.coli and Salmonella spp., based on the usage of innovative diagnostic methods. Even though, attenuated and live vaccines are continuously produced for immunization of poultry against enterobacterias, salmonellosis and colibacillosis, these diseases remain among the most encountered bacterial infections in poultry industry. Nowadays, poultry breeding in Albania has a very heterogeneous characteristic. The development of poultry industry and breeding of many avian species is mainly based on the existence of intensive modern farms with huge capacities, which often are mixed in another form- widely distributed in country, such as rural breeding, extensive and family ones. Many in vivo and in vitro studies have not yet clarified the mechanisms with which pathogen enterobacters in poultry are able to cause the infection. The routine diagnose in the field, followed by isolation of E. coli and species of Salmonella genres in reference laboratories cannot lead in classification or full recognition of circulative strains in a territory, if it is not performed a differentiation among the present microorganisms in intensive farms and those in rural areas. Foremost, it cannot be concluded the fact whether these strains are acting as prime pathogens or are part of secondary infections, which occur very often in intensive poultry breeding industry.
Mechanisms of quinolone resistance in Salmonella spp. / Mecanismos de resistência às quinolonas em Salmonella spp.  [cached]
Roberta Barreiros de Souza,Marciane Magnani,Tereza Cristina Rocha Moreira de Oliveira
Semina : Ciências Agrárias , 2010,
Abstract: Salmonellosis is a common and widespread zoonotic disease of humans and a frequent cause of foodborne disease. Treatment of severe and systemic salmonellosis is usually done with fluoroquinolones. In this review resistance mechanisms of Salmonella to quinolones are discussed. Single point mutations in the quinolone resistant determining region (QRDR) of the gyrA gene may be sufficient to generate high levels of resistance to non-fluorated quinolones and also may decrease the fluoroquinolones susceptibility. Other resistance mechanisms that should be considered are mutations in parC gene, the possibility of acquiring resistance through plasmidial transference and hyper-expression of efflux pumps. Fluoroquinolones resistance is still relatively uncommon in Salmonella compared to other species belonging to the Enterobacteriaceae family. However, the more careful use of fluoroquinolones in veterinary and human medicine is essential to decrease the selective pressure which can avoid the emergence and spread of resistant clones and consequently maintain the clinical efficacy of this group of antibiotics. A salmonelose é uma zoonose de importancia mundial e uma das mais freqüentes doen as de origem alimentar. As fluoroquinolonas s o a principal op o para o tratamento de salmoneloses graves ou sistêmicas. Esta revis o de literatura teve como objetivo apresentar os principais mecanismos envolvidos na resistência de Salmonella spp a estes antimicrobianos. Muta es de ponto na Regi o Determinante de Resistência à Quinolona (QRDR) do gene gyrA podem gerar altos níveis de resistência a quinolonas n o-fluoradas, além de reduzir a suscetibilidade as fluoroquinolonas. Outros mecanismos de resistência que também precisam ser considerados s o as muta es no gene parC, a possibilidade do envolvimento de plasmídios de resistência e o sistema de efluxo ativo. A resistência às fluoroquinolonas ainda é incomum em Salmonella spp., quando comparada a outros gêneros da família Enterobacteriaceae. No entanto, o uso criterioso de fluoroquinolonas na medicina humana e veterinária é essencial para reduzir a press o seletiva e evitar a emergência e dissemina o de clones resistentes, mantendo o espectro de a o e a eficácia clínica desta classe terapêutica.
Analysis of risk factors from salmonella infections and determination of critical control points in poultry industry production chain  [PDF]
Velhner Maja,Plav?a Nada,Rackov Olga,Orli? Du?an
Veterinarski Glasnik , 2005, DOI: 10.2298/vetgl0504453v
Abstract: This paper encompasses problems related to infection caused by Salmonella spp in poultry. The need to carry out adequate control measures and to provide safe food is emphasized. Using experiences from other countries, critical control points are presented in flocks during rearing and in hatcheries. In attempt to diagnose disease as early as possible and to advise proper therapy, the significance of serology monitoring is underlined. In order to produce safe food there is a need to control disease applying our Regulations concerning eradication of Salmonella spp in poultry flocks that is given in Official paper of Republic of Serbia No 6&88 and also to include serology monitoring in poultry flocks. Veterinary practitioners are expected to perform analysis of critical control points in poultry industry as well as to determine specificity and differences in production for single farms, which would enable more effective struggle with diseases in general.
Association of Transferable Quinolone Resistance Determinant qnrB19 with Extended-Spectrum β-Lactamases in Salmonella Give and Salmonella Heidelberg in Venezuela  [PDF]
Fanny González,María Araque
International Journal of Microbiology , 2013, DOI: 10.1155/2013/628185
Abstract: Four nontyphoidal Salmonella strains with resistance to extended-spectrum cephalosporins and nonclassical quinolone resistance phenotype were studied. Two S. Give were isolated from pediatric patients with acute gastroenteritis, and two S. Heidelberg were recovered from raw chicken meat. Phenotypic characterization included antimicrobial susceptibility testing and detection of extended-spectrum β-lactamases (ESBLs) by the double-disc synergy method. The detection of quinolone resistance-determining regions (QRDR) of gyrA, gyrB, and gyrC genes, genes, and plasmid-mediated quinolone resistance (PMQR) determinants was carried out by molecular methods. Plasmid analysis included Southern blot and restriction patterns. Transferability of resistance genes was examined by transformation. genes were detected in S. Give SG9611 and in the other three strains: S. Give SG9811, S. Heidelberg SH7511, and SH7911. Regardless of origin and serovars, the qnrB19 gene was detected in the 4 strains studied. All determinants of resistance were localized in plasmids and successfully transferred by transformation. This study highlights the circulation of qnrB19 associated with , , and in S. Give and S. Heidelberg in Venezuela. The recognition of factors associated with increasing resistance and the study of the molecular mechanisms involved can lead to a more focused use of antimicrobial agents. 1. Introduction Nontyphoidal Salmonella (NTS) are one of the major causes of foodborne infections related to the ingestion of contaminated animal food products in humans [1]. In most cases, these infections are confined to the gastrointestinal tract and are self-limiting. However, for immunocompromised and/or elderly patients, as well as for invasive or prolonged infections, antibiotic treatment is recommended [2]. Fluoroquinolones and extended-spectrum β-lactams are the first-choice agents for these cases but the increase of the multidrug resistance (MDR) Salmonella strains reduces the available treatment options [1–5]. The emergence of Salmonella spp. isolates that display resistance to extended-spectrum β-lactams is mediated by plasmids and is an increasing public health concern [3–5]. The resistance to fluoroquinolones is typically mediated by alterations in the target enzymes DNA gyrase and topoisomerase IV or changes in drug entry and efflux. Also, three plasmid-mediated mechanisms conferring decreased susceptibility to ciprofloxacin have been recently described: QepA efflux, Aac(6′)-Ib-cr aminoglycoside acetyltransferase, and QNR proteins (qnrA, qnrB, qnrC, qnrD, and qnrS) [6,
Study on the incidence of Salmonella enteritidis in Poultry and meat Samples by Cultural and PCR Methods  [cached]
Putturu Ramya,Thirtham Madhavarao,Lakkineni Venkateswara Rao
Veterinary World , 2012, DOI: 10.5455/vetworld.2012.541-545
Abstract: Aim: To study the incidence of S.enteritidis in poultry and meat samples by cultural and PCR methods. Materials and Methods: A total of 130 samples (25 each of chicken, mutton, poultry faeces, cloacal samples and 10 each of liver, spleen and kidney) collected from different sources were subjected to cultural and PCR methods for the presence of Salmonella and Salmonella enteritidis. Primers for invA and sefA gene were used for Salmonella and S.enteritidis respectively. Results: Out of 130 samples, 87 were positive for Salmonella spp. i.e. chicken-16(64%), mutton-12(48%), faeces-23(92%), cloacal swabs-23(92%), liver-5(50%), spleen and kidney samples-4(40%) each by PCR methods, whereas 77 were positive by cultural method i.e. chicken-14(56%), mutton-10(40%), faeces-22(88%), cloacal swabs-21(84%), liver-4(40%), spleen and kidney-3(30% each). Out of 87 positive for Salmonella by PCR method, 59(chicken-12, mutton-7, faeces-17, cloacal swabs-15, liver-3, spleen-2, kidney-3) were positive for S.enteritidis. High incidence of S.enteritidis (68%) in all the above samples are indicative of unhygienic conditions in poultry farms. Selective enrichment with Rappaport-Vassilidias (RV) broths and Tetrathionate (TT) broths were superior over Selenite-F (SF) and Selenite cysteine (SC) broths. Conclusions: High incidence of S.enteritidis was seen in most of poultry samples like chicken, kidney, liver and it's faeces than mutton, which was indicative of contamination of S.enteritidis is more prevalent in poultry farms. [Vet World 2012; 5(9.000): 541-545]
Epidemiology of plasmid-mediated quinolone resistance in salmonella enterica serovar typhimurium isolates from food-producing animals in Japan
Tetsuo Asai, Chizuru Sato, Kaori Masani, Masaru Usui, Manao Ozawa, Tomoe Ogino, Hiroshi Aoki, Takuo Sawada, Hidemasa Izumiya, Haruo Watanabe
Gut Pathogens , 2010, DOI: 10.1186/1757-4749-2-17
Abstract: Salmonella enterica serovar Typhimurium is prevalent in many animal species [1-3] including food-producing animals that are considered to be reservoirs for human infection. S. Typhimurium was the top 5 serovar found most frequently in cases of Salmonella foodborne illness in Japan between 2006 and 2010 https://hasseidoko.mhlw.go.jp/Byogentai/Pdf/data48e.pdf webcite. Multidrug-resistant S. Typhimurium definitive phage type 104 (DT104) causes human salmonellosis in Japan [3]. S. Typhimurium DT104 was first isolated in the late 1980 s, and has spread widely among food-producing animals across Japan [3-5]. Although a decreased proportion of DT104-related isolates among the animals was found between 2002 and 2005, multidrug-resistant S. Typhimurium remains prevalent among food-producing animals in Japan [6].In Japan, fluoroquinolone drugs were approved in veterinary fields in 1991 and are commonly used for treatment of bacterial diseases such as enteritis and pneumonia in food-producing animals [7]. In 2001, fluoroquinolone resistance was found in S. Choleraesuis from pigs [8] and S. Typhimurium from cattle [9]. In addition, a fluoroquinolone-resistant S. Typhimurium was identified in bovine isolates in 2005 [6]. The mechanism of fluoroquinolone resistance in these isolates is the mutation of quinolone resistance-determining regions (QRDRs) in DNA gyrase and topoisomerase IV [8,9]. In 2006, qnrS1 was identified in two S. Typhimurium isolates (including one DT104 isolate) from dairy cows and beef cattle, and S. Thompson from poultry in Japan [10]. The report identified the potential risk of foodborne infections of Salmonella conferring the gene from food-producing animals to humans in Japan.Quinolone resistance mechanisms mediated by plasmids are responsible for target protection such as the qnr genes, active efflux such as qepA, and enzymatic modifications such as aac(6')Ib-cr [11]. The plasmid-mediated quinolone resistance (PMQR) genes contribute to a reduction of quino
Quinolone and Multidrug Resistant Salmonella typhi in Ibadan, Nigeria
Olufunmilola B. Makanjuola,Rasheed A. Bakare,Samuel A. Fayemiwo
International Journal of Tropical Medicine , 2012, DOI: 10.3923/ijtmed.2012.103.107
Abstract: Typhoid fever remains prevalent worldwide especially in a developing country like Nigeria. Many first line drugs such as chloramphenicol were discontinued due to Multi-Drug Resistant (MDR) Salmonella Typhi (S. typhi). Quinolones are now the recommended therapy but in spite of their usefulness there are several reports of failure of therapy due to quinolone resistance. This study sought to find the prevalence of quinolone resistant and MDR S. typhi in this environment. About 146 (4.6%) out of the 3184 blood culture samples collected for the study yielded Salmonella typhi disk diffusion antibiotic susceptibility testing was carried out for the following antibiotics: chloramphenicol, ampicillin, amoxicillin, amoxicillin-clavulanic acid, nalidixic acid, ciprofloxacin, azithromycin and ceftriaxone. The minimum inhibitory concentration of ciprofloxacin was determined against the isolates using broth macrodilution technique. Of the Salmonella typhi isolates 37.7, 32.2, 38.4 and 50.7% were susceptible to chloramphenicol, cotrimoxazole, ampicillin and amoxicillin, respectively while susceptibility to amoxicillin-clavulanic acid, nalidixic acid, ciprofloxacin, azithromycin and ceftriaxone were 87.7, 91.1, 95.9, 99.3 and 100%, respectively. The MIC50 and MIC90 of ciprofloxacin were 0.06 and 0.125 μg mL-1, respectively. The prevalence of multidrug resistance was 56.2% while that of quinolone resistance was 8.9%. There is high prevalence of multidrug resistant Salmonella typhi therefore, the use of chloramphenicol and other previous first line antibiotics should be discouraged. Though, resistance appears to be emerging, quinolones remain useful in treating typhoid fever in this environment but surveillance should be continuous.
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