Página 1 dos resultados de 1433 itens digitais encontrados em 0.008 segundos

Desenvolvimento e validação de métodos SPE-LC-MS e MEPS-LC-MS para quantificação de fluoroquinolonas em matrizes aquosas; Development and validation of methods SPE-LC-MS and MEPS-LC-MS for determination of fluoroquinolones in water samples

Amparo, Maura Roquete
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 19/04/2013 PT
Relevância na Pesquisa
37.08%
Os antimicrobianos, especialmente a classe das fluoroquinolonas (FQs), são utilizados em grandes quantidades na medicina humana e veterinária. Uma atenção especial deve ser dada à ocorrência desses fármacos em diferentes matrizes ambientais, devido a potencialidade de propagação da resistência bacteriana. As principais fontes dessa contaminação são os esgoto industrial, urbanos, esgoto sanitário de hospital e de fazendas que utilizam antibióticos com finalidades veterinárias. Após a ingestão, os antimicrobianos são excretados na sua forma inalterada e, devido a baixa eficiência dos sistemas convencionais de tratamento de esgoto, são eventualmente liberados para o meio aquático. Diferentes métodos têm sido desenvolvidos para a determinação de FQs em amostras aquosas diversas, tais como esgoto sanitário , água de abastecimento, águas superficiais e esgoto sanitário de hospital. A maior parte dessas amostras ambientais é complexa e exige uma série de etapas de preparo, limpeza e pré-concentração; de maneira que, nos últimos anos, extensos esforços têm sido feitos para o desenvolvimento de novas técnicas de preparo de amostra que reduzam o tempo, trabalho, consumo de solvente e que permitam melhor desempenho do processo analítico. Nesse estudo foram desenvolvidos dois métodos de extração - a extração em fase sólida (SPE ) e a microextração por sorvente empacotado (MEPS) - sendo a separação...

HPLC-FD Method Validation for Determination of Several Fluoroquinolones in Biodegradation Assays

Maia, Alexandra S.; Ribeiro, Ana R.; Castro, Paula M. L.; Tiritan, Maria E.
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Conferência ou Objeto de Conferência
Publicado em /06/2011 ENG
Relevância na Pesquisa
36.94%
The present concern in pharmaceuticals in the environment is well known and research studies in this area have been regularly reported [1]. Pharmaceuticals reach the environment by several ways but mostly due to their incorrect disposal and the incomplete elimination during the treatment processes in Wastewater Treatment Plants (WWTP). These residues continuously enter aquatic environments and many of them are resistant to degradation, being so called as pseudo-persistent pollutants [2]. In aquatic compartments, pharmaceutical residues reach concentrations in the ng/L to µg/L range [3]. Antibiotics are a class extensively studied due to its implications on development of multi-resistant bacteria. This work describes a validated HPLC (High Performance Liquid Chromatography) method with Fluorescence Detection for monitorization of biodegradation of four fluoroquinolones: Ofloxacin (OFL), Norfloxacin (NOR), Ciprofloxacin (CPF) and Moxifloxacin (MOX). The separation of the target pharmaceuticals was performed at 38ºC using a Luna 3µ PFP(2) 100 A (150 x 4.60 mm) column in isocratic mode with a mixture of 0.1% triethylamine (TEA) in water acidified to pH = 2.2 with trifluoroacetic acid (TFA) and ethanol as mobile phase. The validated method demonstrated selectivity...

Biodegradation of fluoroquinolones by a bacterial consortium

Maia, Alexandra S.; Duque, Anouk F.; Ribeiro, Ana R.; Tiritan, Maria E.; Castro, Paula M. L.
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Artigo de Revista Científica
Publicado em //2011 ENG
Relevância na Pesquisa
37.08%
The present concern in pharmaceuticals in the environment is well known and research studies in this area have been regularly reported. Pharmaceuticals reach the environment by several ways but mostly due to their incorrect disposal and the incomplete elimination during the treatment processes in Wastewater Treatment Plants (WWTP). These residues continuously enter aquatic environments and many of them are resistant to degradation, being so called as pseudo-persistent pollutants. In aquatic compartments, pharmaceutical residues reach concentrations in the ng L-1 to µg L-1 range. This work describes the biodegradation of four fluoroquinolones, Ofloxacin (OFL), Norfloxacin (NOR), Ciprofloxacin (CPF) and Moxifloxacin (MOX), by a bacterial consortium constituted by three bacterial species isolated in our labs, namely F11, FP1 and S2, known to degrade different aromoatic fluorinated compounds. The experiments were conducted in batch mode using a mineral medium supplemented with acetate and 10 mg l-1 of each compound or 10 mg l-1 of a mix of the compounds. The bacterial consortium was capable of aerobic biodegradation of OFL, NOR and CPF during successive feedings of the compounds to the medium, as measured by monitoring removal of the compounds by HPLC-FD and fluoride release by potenciometry. Degradation profile of the fluoroquinolones used in this study indicated that intermediate metabolites were accumulated. Two of the initial constituting strains...

Development and Optimization of an Online SPE-HPLC-FD Method for Quantification of Fluoroquinolones in Wastewater Effluents

Meira, Bernardo; Maia, Alexandra S.; Gonçalves, Virgínia M. F.; Ribeiro, Ana R.; Tiritan, Maria E.
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Artigo de Revista Científica
Publicado em /06/2013 ENG
Relevância na Pesquisa
37.19%
Fluoroquinolones are antimicrobial agents widely found in environmental matrices and extensively studied due to their persistence and implications for multiresistant bacteria. The presence of fluoroquinolones in the environment is mainly due to the incapability of wastewater treatment plants (WWTPs) to completely remove those compounds. The amount of fluoroquinolones released through effluents depends on the type of treatment used by the WWTPs. So, accurate analytical methods to quantify those compounds on WWTPs process and in effluents are crucial. Solid phase extraction (SPE) coupled to liquid chromatography is a straightforward technique that provides analyte extraction, cleanup, separation and detection while providing a good reproducibility and efficiency. The purpose of this work was the establishment of a novel method for quantification of Ofloxacin, Norfloxacin, Ciprofloxacin and Moxifloxacin on WWTPs effluents using on-line SPE. Samples were injected directly on a restricted access material column LichroCart 25-4 Lichrospher® RP-18 ADS (25 μm) and then transferred to an analytical column Luna PFP (2) (150 x 4.6 mm ID, 100 Å, 3 μm) for separation in isocratic mode with a mixture of 0.1% triethylamine in water (acidified to pH = 2.2 with trifluoroacetic acid) and ethanol as mobile phase; column oven was set at 45ºC. The detection was performed by fluorescence with an excitation wavelength of 290 nm and an emission wavelength of 460 nm. The injection volume of 100 μL of previous preconcentrated sample was compared with larger volume injection of only filtered effluent samples. The study was conducted with effluent samples collected from a municipal WWTP in the north of Portugal.

Avaliação dos efeitos anti-proliferativos de fármacos inibidores de topoisomerases do tipo II em promastigotas de Leishmania infantum

Franco, Susana Maria Gomes
Fonte: Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária Publicador: Universidade Técnica de Lisboa. Faculdade de Medicina Veterinária
Tipo: Dissertação de Mestrado
Publicado em 05/06/2013 POR
Relevância na Pesquisa
27.26%
Dissertação de Mestrado Integrado em Medicina Veterinária; A Leishmaniose canina é uma doença endémica e de elevada incidência em Portugal. O arsenal farmacológico disponível não permite a cura parasitológica, causa efeitos tóxicos graves no organismo e os protocolos terapêuticos são onerosos. De forma a aumentar o leque de alternativas no combate a este protozoário foram avaliados os efeitos inibitórios das fluoroquinolonas em promastigotas de Leishmania infantum. Esta família de antibióticos são inibidores de topoisomerases de tipo II, enzimas fundamentais para o metabolismo dos ácidos nucleicos bacterianos. Neste estudo foi analisado, in vitro, o efeito anti-proliferativo de um conjunto de fluoroquinolonas comerciais (quatro gerações), visando várias concentrações (0,1 μM, 1 μM, 10 μM e 100 μM), em promastigotas de L. infantum. Esta análise foi realizada através de um ensaio colorimétrico de viabilidade celular e, paralelamente, por observações e contagens ao microscópio ótico, sendo os resultados confrontados com um controlo positivo (antimoniato de meglumina). Os resultados obtidos foram também comparados com os resultados obtidos a partir de culturas de promastigotas não tratados (controlo negativo). Após a análise dos resultados...

Fluoroquinolones in industrial poultry production, bacterial resistance and food residues:a review

Gouvêa,R; Santos,FF dos; Aquino,MHC de; Pereira VL de,A
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2015 EN
Relevância na Pesquisa
36.94%
Fluoroquinolones are antimicrobial agents frequently used in poultry production and in human medicine. The use of such substances must comply with safety criteria, including withdrawal periods, doses, and treatment duration, as their misuse and abuse may cause bacterial resistance and the presence of residues in edible tissues. Consequently, the consumption of animal products with fluoroquinolone residues may result in the transmission of resistant bacteria. In addition, if residues are beyond the acceptable levels, fluoroquinolone active metabolites are harmful to human health. This article presents a review on the use of antimicrobials of the fluoroquinolone class in poultry production, focusing on the development of bacterial resistance to these drugs and the presence of their residues in poultry products.

Environmental contamination by fluoroquinolones

Frade,Verônica Maria Fadário; Dias,Meriellen; Teixeira,Antonio Carlos Silva Costa; Palma,Mauri Sergio Alves
Fonte: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas Publicador: Universidade de São Paulo, Faculdade de Ciências Farmacêuticas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 EN
Relevância na Pesquisa
37.36%
Over the past few decades, a high number of pharmaceuticals have been detected in surface, ground and drinking waters. This contamination comes from domestic sewage, livestock, hospitals and chemical-pharmaceutical industries. Typical examples of these pollutants are the fluoroquinolones - powerful antibiotics used in human and veterinary medicine. The presence of fluoroquinolones in the environment can pose a serious threat to the ecosystem and to human health due to their high consumption globally: in 1998, around 120 tons were produced. Even at low environmental concentrations, antibiotics stimulate bacterial resistance. The consequences of the presence of fluoroquinolones in the environment are not fully understood, but are known to be toxic to plants and aquatic organisms. Approximately 85% of the fluoroquinolones present in influents can be removed by conventional wastewater treatment plants, but the removed fraction is frequently accumulated in the sludge, which is sometimes used as fertilizer, representing an additional input route into the environment. The removal of fluoroquinolones by biological treatment is ineffective, and it is believed that only advanced oxidation technologies are able to destroy these emerging pollutants.

DNA topoisomerase targets of the fluoroquinolones: A strategy for avoiding bacterial resistance

Zhao, Xilin; Xu, Chen; Domagala, John; Drlica, Karl
Fonte: The National Academy of Sciences of the USA Publicador: The National Academy of Sciences of the USA
Tipo: Artigo de Revista Científica
Publicado em 09/12/1997 EN
Relevância na Pesquisa
27.31%
Fluoroquinolones are antibacterial agents that attack DNA gyrase and topoisomerase IV on chromosomal DNA. The existence of two fluoroquinolone targets and stepwise accumulation of resistance suggested that new quinolones could be found that would require cells to obtain two topoisomerase mutations to display resistance. For wild-type cells to become resistant, the two mutations must be acquired concomitantly. That is expected to occur infrequently. To identify such compounds, fluoroquinolones were tested for the ability to kill a moderately resistant gyrase mutant. Compounds containing a C8-methoxyl group were particularly lethal, and incubation of wild-type cultures on agar containing C8-methoxyl fluoroquinolones produced no resistant mutant, whereas thousands arose during comparable treatment with control compounds lacking the C8 substituent. When the test strain contained a preexisting topoisomerase IV mutation, which by itself conferred no resistance, equally high numbers of resistant mutants were obtained for C8-methoxyl and control compounds. Thus C8-methoxyl fluoroquinolones required two mutations for expression of resistance. Although highly lethal, C8-methoxyl fluoroquinolones were not more effective than C8-H controls at blocking bacterial growth. Consequently...

Pregnancy Outcome Following Gestational Exposure to Fluoroquinolones: a Multicenter Prospective Controlled Study

Loebstein, Ronen; Addis, Antonio; Ho, Elaine; Andreou, Roseann; Sage, Suzanne; Donnenfeld, Alan E.; Schick, Betsy; Bonati, Maurizio; Moretti, Myla; Lalkin, Arieh; Pastuszak, Anne; Koren, Gideon
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /06/1998 EN
Relevância na Pesquisa
27.26%
Concerns regarding the teratogenicity of fluoroquinolones have resulted in their restricted use during gestation. This is despite an increasing need for their use due to emerging bacterial resistance. The objectives of the present investigation were to evaluate pregnancy and fetal outcomes following maternal exposure to fluoroquinolones and to examine whether in utero exposure to quinolones is associated with clinically significant musculoskeletal dysfunctions. We prospectively enrolled and followed up 200 women exposed to fluoroquinolones (norfloxacin, ciprofloxacin, ofloxacin) during gestation. Pregnancy outcome was compared with that for 200 controls matched for age and for smoking and alcohol consumption habits. Controls were exposed to nonteratogenic, nonembryotoxic antimicrobial agents matched by indication, duration of therapy (±3 days), and trimester of exposure. Rates of major congenital malformations did not differ between the group exposed to quinolones in the first trimester (2.2%) and the control group (2.6%) (relative risk, 0.85; 95% confidence interval, 0.21 to 3.49). Women treated with quinolones had a tendency for an increased rate of therapeutic abortions compared with the rate among women exposed to nonteratogens (relative risk...

In Vitro and In Vivo Activities of Newer Fluoroquinolones against Vibrio vulnificus

Tang, Hung-Jen; Chang, Ming-Chung; Ko, Wen-Chien; Huang, Kun-Yen; Lee, Chih-Lung; Chuang, Yin-Ching
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /11/2002 EN
Relevância na Pesquisa
27.26%
The MICs of six fluoroquinolones as well as minocycline and cefotaxime for 46 clinical isolates of Vibrio vulnificus were determined by the agar dilution method. All the drugs tested had good activities against all isolates, with the MICs at which 90% of the isolates tested were inhibited (MIC90s) by five of the fluoroquinolones ranging between 0.03 and 0.06 μg/ml. The MIC90 of lomefloxacin, on the other hand, was 0.12 μg/ml. Time-kill studies were conducted with these agents and a clinical strain of V. vulnificus, VV5823. When approximately 5 × 105 CFU of V. vulnificus/ml was incubated with any one of the above-mentioned six fluoroquinolones at concentrations of two times the MIC, there was an inhibitory effect on V. vulnificus that persisted for more than 48 h with no noted regrowth. The efficacies of the fluoroquinolones were further evaluated in vivo in the mouse model of experimental V. vulnificus infection and compared to the efficacy of a combination therapy using cefotaxime plus minocycline. With an inoculum of 1.5 × 107 CFU, 28 (87.5%) of 32 mice in the cefotaxime-minocycline-treated group survived and 29 (91%) of the 32 mice in the moxifloxacin-treated group survived while none of the 32 mice in the control group did. With an inoculum of 3.5 × 107 CFU...

In Vitro and In Vivo Activities of Fluoroquinolones against Aeromonas hydrophila

Ko, Wen-Chien; Chiang, Shyh-Ren; Lee, Hsin-Chun; Tang, Hung-Jen; Wang, Yin-Yi; Chuang, Yin-Ching
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /07/2003 EN
Relevância na Pesquisa
27.26%
Aeromonas hydrophila, an uncommon human pathogen, can cause invasive infections in immunocompromised individuals. As the fluoroquinolones have been shown to be active in vitro against mesophilic aeromonads and clinical experience with the use of fluoroquinolones to treat aeromonads infections is limited, the antimicrobial activities of five selected drugs (ciprofloxacin, gatifloxacin, levofloxacin, lomefloxacin, and moxifloxacin) against A. hydrophila were studied in vitro and in mice. The MICs of the fluoroquinolones (except lomefloxacin), cefotaxime, and minocycline for 90% of 64 clinical isolates of A. hydrophila tested by the agar dilution method were ≤1 μg/ml. With a clinical cefotaxime-resistant strain, Ah 2743, in an in vitro time-kill study, at an inoculum of 7 × 105 CFU/ml incubated with fluoroquinolones, cefotaxime, or minocycline at concentrations equal to twice the MICs, the inhibitory effect lasted for less than 6 h and regrowth occurred thereafter. In an animal model with female BALB/c mice intraperitoneally infected with an inoculum of 1.1 × 107 CFU of Ah 2743, more mice in the ciprofloxacin-treated group survived (72.2%) than in the cefotaxime-, minocycline-, or cefotaxime-minocycline-treated group (P < 0.00001...

In Vitro Activities of New Fluoroquinolones against Campylobacter jejuni and Campylobacter coli Isolates Obtained from Humans in 1980 to 1982 and 1997 to 2001

Krausse, Rea; Ullmann, Uwe
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /09/2003 EN
Relevância na Pesquisa
27.31%
The antibacterial activities of three newly developed fluoroquinolones (gatifloxacin, levofloxacin, and moxifloxacin) against a total of 307 gastrointestinal human isolates of Campylobacter jejuni and Campylobacter coli collected during 1980 to 1982 and 1997 to 2001 were examined and compared to those of ciprofloxacin and the unrelated antibacterial agents, clarithromycin, erythromycin, and tetracycline by using the agar plate dilution method. All of the fluoroquinolones exhibited a good activity against Campylobacter, and some of them were more active than ciprofloxacin, the macrolides, and tetracycline. Among the fluoroquinolones, gatifloxacin and moxifloxacin showed the highest anticampylobacter activity, with MICs at which 50% of the isolates tested are inhibited (MIC50s) and MIC90s of 0.125 and 4 μg/ml, respectively; the MIC50 for both levofloxacin and ciprofloxacin was 0.25, and the MIC90s were 16 and 32 μg/ml, respectively. About 30% of the strains were found to be resistant to at least one fluoroquinolone. Resistance to gatifloxacin occurred in 9.8% of the isolates tested, and resistance to the other fluoroquinolones occurred in 19.9 to 27.4% of the isolates tested; the frequency of cross-resistance was 35.7 to 100%. An increase in fluoroquinolone resistance from 0% in 1980 to 1982 to 11.8 to 29% in 1997 and 1998...

Mechanisms of clinical resistance to fluoroquinolones in Staphylococcus aureus.

Nakanishi, N; Yoshida, S; Wakebe, H; Inoue, M; Yamaguchi, T; Mitsuhashi, S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1991 EN
Relevância na Pesquisa
27.26%
Mechanisms of Staphylococcus aureus resistance to fluoroquinolones were characterized. Subunit A and B proteins of DNA gyrase were partially purified from fluoroquinolone-susceptible strain SA113 and resistant isolate MS16405, which was 250- to 1,000-fold less susceptible to fluoroquinolones such as ciprofloxacin, norfloxacin, ofloxacin, temafloxacin, and sparfloxacin than SA113 was. The supercoiling activity of the gyrase from SA113 was inhibited by the fluoroquinolones, and the 50% inhibitory concentrations of the drugs correlated well with their MICs. In contrast, the gyrase from MS16405 was insensitive to inhibition of supercoiling by all of the quinolones tested, even at 800 micrograms/ml. Combinations of heterologous gyrase subunits showed that subunit A from MS16405 conferred fluoroquinolone resistance, suggesting that an alteration in gyrase subunit A is a cause of the fluoroquinolone resistance in MS16405. Uptake of hydrophilic fluoroquinolones such as ciprofloxacin and norfloxacin by MS16405 was significantly lower than that by SA113. Furthermore, this difference was abolished by the addition of an energy inhibitor, carbonyl cyanide m-chlorophenylhydrazone, suggesting that an alteration in an energy-dependent process, such as an active efflux of hydrophilic quinolones...

Risk Factors Associated with Colonization by Pneumococci with Reduced Susceptibility to Fluoroquinolones in Adult Outpatients

Jiménez, M. Raquel Marín; Bellido, Juan Luis Muñoz; García Rodríguez, José Ángel
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /03/2005 EN
Relevância na Pesquisa
27.26%
We developed a case-control study in order to identify risk factors associated with pharyngeal colonization by Streptococcus pneumoniae with reduced susceptibility to fluoroquinolones (ciprofloxacin MIC, ≥4 μg/ml). A total of 400 patients were studied for colonization by quinolone-nonsusceptible S. pneumoniae (QNSP) isolates and risk factors for this colonization. Isolate susceptibility was determined by the agar dilution method. Forty patients were colonized by QNSP (case patients), and 360 patients were not colonized by QNSP (control patients). The MIC range of ciprofloxacin for QNSP isolates was 4 to 8 μg/ml. No isolates were resistant to levofloxacin and moxifloxacin. Risk factors significantly associated with QNSP colonization, according to univariate analysis, were recent hospitalizations (odds ratio [OR], 3.43; 95% confidence interval [CI], 1.6 to 7.2; P < 0.01) and prior exposure to fluoroquinolones (OR, 6.04; 95% CI, 3.0 to 12.0; P < 0.01). Other factors such as chronic obstructive pulmonary disease (OR, 1.94; 95% CI; 0.7 to 5.0), prior exposure to penicillins (OR, 1,68; 95% CI, 0.8 to 3.3) and prior exposure to macrolides (OR 2; 95% CI, 0.6 to 6.2) were more frequent among patients colonized with QNSP, but there was no statistical significance. Multivariate analysis showed that exposure to fluoroquinolones was the only independent factor associated with colonization by QNSP (OR...

Role of a qnr-Like Gene in the Intrinsic Resistance of Enterococcus faecalis to Fluoroquinolones▿

Arsène, Stéphanie; Leclercq, Roland
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.36%
Fluoroquinolones are poorly active against enterococci. Recently, plasmid-borne resistance to fluoroquinolones due to the qnr gene was reported in members of the Enterobacteriaceae family. The gene encodes a pentapeptide repeat protein that protects DNA gyrase from inhibition by fluoroquinolones. We have identified in the genome of Enterococcus faecalis V583 a qnr-like gene, named E. faecalis qnr (qnrE. faecalis), encoding a putative pentapeptide repeat protein that shares 25% identity with Qnr. To assess its potential role in the intrinsic resistance of E. faecalis to fluoroquinolones, qnrE. faecalis was inactivated in E. faecalis JH2-2 by insertion of the thermosensitive vector pG1KT. This strain was then complemented with qnrE. faecalis cloned in the multicopy plasmid pORI23. The effects of its overexpression were also studied. Inactivation of the qnrE. faecalis gene resulted in twofold decreases in the MICs of ofloxacin and ciprofloxacin. When the gene was complemented or overexpressed, MICs of fluoroquinolones increased four- to nine-fold, leading to MICs of ofloxacin and ciprofloxacin equal to 32 μg/ml and 8 μg/ml, respectively. The E. faecalis Qnr (QnrE. faecalis) protein was produced and purified. QnrE. faecalis protein protected Escherichia coli DNA gyrase from inhibition by ofloxacin. The qnrE. faecalis gene was then introduced into E. coli DH10B...

Clostridium difficile Isolates Resistant to Fluoroquinolones in Italy: Emergence of PCR Ribotype 018 ▿

Spigaglia, Patrizia; Barbanti, Fabrizio; Dionisi, Anna Maria; Mastrantonio, Paola
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.36%
Recent evidence strongly suggests an association between the use of fluoroquinolones and Clostridium difficile infection (CDI). Resistance to fluoroquinolones has been described not only in the hypervirulent strain 027, but also in other important PCR ribotypes circulating in hospital settings. In a European prospective study conducted in 2005, strains resistant to moxifloxacin represented 37.5% of C. difficile clinical isolates. In this study, we investigated a sample of 147 toxigenic C. difficile isolates, collected in Italy from 1985 to 2008, for the presence of mutations in gyr genes that conferred resistance to fluoroquinolones based on a LightCycler assay. Results were confirmed by the determination of MICs for moxifloxacin. Strains resistant to moxifloxacin were also investigated for resistance to three other fluoroquinolones and for a possible association between fluoroquinolone and macrolide-lincosamide-streptogramin B resistance. C. difficile isolates were typed by PCR ribotyping. In total, 50 clinical isolates showed substitutions in gyr genes and were resistant to fluoroquinolones. Ninety-six percent of the C. difficile resistant isolates showed the substitution Thr82-to-Ile in GyrA, as already observed in the majority of resistant strains worldwide. A significant increase of resistance (P < 0.001) was observed in the period 2002 to 2008 (56% resistant) compared to the period 1985 to 2001 (10% resistant). Coresistance with erythromycin and/or clindamycin was found in 96% (48/50) of the isolates analyzed and...

Susceptibility of Streptococcus pneumoniae to Fluoroquinolones in Canada▿

Patel, Samir N.; McGeer, Allison; Melano, Roberto; Tyrrell, Gregory J.; Green, Karen; Pillai, Dylan R.; Low, Donald E.;
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /08/2011 EN
Relevância na Pesquisa
27.31%
Ciprofloxacin, the first fluoroquinolone to be used to treat lower respiratory tract infections (LRTI), demonstrates poor potency against Streptococcus pneumoniae, and its use has been associated with the emergence of resistance. During the last decade, fluoroquinolones with enhanced in vitro activity against S. pneumoniae have replaced ciprofloxacin for the treatment of LRTI. Here, we analyzed the impact of more active fluoroquinolone usage on pneumococci by examining the fluoroquinolone usage, prevalence of fluoroquinolone resistance, and mutations in the genes that encode the major target sites for the fluoroquinolones (gyrA and parC) in pneumococcal isolates collected in Canada-wide surveillance. A total of 26,081 isolates were collected between 1998 and 2009. During this time period, total per capita outpatient use of fluoroquinolones increased from 64 to 96 prescriptions per 1,000 persons per year. The proportion of prescriptions for respiratory tract infection that were for fluoroquinolones increased from 5.9% to 10.7%, but the distribution changed: the proportion of prescriptions for ciprofloxacin decreased from 5.3% to 0.5%, and those for levofloxacin or moxifloxacin increased from 1.5% in 1999 to 5.9% in 2009. The prevalence of ciprofloxacin resistance (MIC ≥ 4 μg/ml)...

Fluoroquinolone susceptibility in Mycobacterium tuberculosis after pre-diagnosis exposure to older- versus newer-generation fluoroquinolones☆

van der Heijden, Yuri F.; Maruri, Fernanda; Blackman, Amondrea; Mitchel, Ed; Bian, Aihua; Shintani, Ayumi K.; Eden, Svetlana; Warkentin, Jon V.; Sterling, Timothy R.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.44%
Fluoroquinolone exposure before tuberculosis (TB) diagnosis is common. We anticipated that exposure to older-generation fluoroquinolones is associated with greater fluoroquinolone MICs in Mycobacterium tuberculosis than exposure to newer agents. A nested case–control study was performed among newly diagnosed TB patients reported to the Tennessee Department of Health (January 2002–December 2009). Each fluoroquinolone-resistant case (n = 25) was matched to two fluoroquinolone-susceptible controls (n = 50). Ciprofloxacin and ofloxacin were classified as older-generation fluoroquinolones; levofloxacin, moxifloxacin and gatifloxacin were considered newer agents. There was no difference between median ofloxacin MIC for isolates from 9 patients exposed only to older fluoroquinolones, 25 exposed only to newer fluoroquinolones, 6 exposed to both and 35 fluoroquinolone-unexposed patients (Kruskal–Wallis, P = 0.35). Using multivariate proportional odds logistic regression adjusting for age and sex, duration of exposure to newer fluoroquinolones was independently associated with higher MIC (OR = 1.79, 95% CI 1.22–2.64), but duration of exposure to older fluoroquinolones was not (OR = 0.94, 95% CI 0.50–1.78). Isolates from patients exposed only to newer fluoroquinolones tended to have mutations at gyrA codons 90...

Prevalence of resistance to aminoglycosides and fluoroquinolones among Pseudomonas aeruginosa strains in a University Hospital in Northeastern Poland

Michalska,Anna Diana; Sacha,Pawel Tomasz; Ojdana,Dominika; Wieczorek,Anna; Tryniszewska,Elzbieta
Fonte: Sociedade Brasileira de Microbiologia Publicador: Sociedade Brasileira de Microbiologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 EN
Relevância na Pesquisa
36.94%
The present study was conducted to investigate the prevalence of genes encoding resistance to aminoglycosides and fluoroquinolones among twenty-five Pseudomonas aeruginosa isolated between 2002 and 2009. In PCR, following genes were detected: ant(2")-Ia in 9 (36.0%), aac(6')-Ib in 7 (28.0%), qnrB in 5 (20.0%), aph(3")-Ib in 2 (8.0%) of isolates.

Strategies to enhance the removal of Fluoroquinolones

Amorim, Catarina L.; Maia, Alexandra S.; Moreira, Irina S.; van Loosdrecht, Mark C.M.; Tiritan, Maria E.; Castro, Paula M.L.
Fonte: Universidade Católica Portuguesa Publicador: Universidade Católica Portuguesa
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
Relevância na Pesquisa
36.94%
Fluoroquinolones (FQs) are broad-spectrum antibiotics that play an important role in the treatment of serious bacterial infections. Currently, several FQs are available but ciprofloxacin (CPF), ofloxacin (OFL) and norfloxacin (NOR) are amongst the most worldwide prescribed antibiotics. Antibiotics can reach wastewater treatment plants (WWTP) from different routes. Thus removal of these contaminants during the biotreatment process is of major importance in order to avoid their release to other environmental matrices. Granular sludge sequencing batch reactors (SBR) constitute a novel biofilm technology for wastewater treatment extremely promising for the treatment of effluents containing toxic compounds. Therefore, in this study a granular sludge SBR, established with activated sludge from a WWTP, was operated for the treatment of an aqueous stream containing FQs. No evidence of FQ biodegradation followed by HPLC with Fluorescence Detection was observed but FQs adsorbed to the aerobic granular sludge, being gradually released into the medium after withdrawal of the FQs in the inlet stream. In a previous study, Labrys portucalensis F11 demonstrated to be able to degrade FQs, namely OFL, NOR and CPF, when supplied individually or as a mixture...