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Accessing the molecular basis of transferable quinolone resistance in Escherichia coli and Salmonella spp from food-producing animals and products

Fri, 01 Jun 2012 00:00:00 GMT

Title: Accessing the molecular basis of transferable quinolone resistance in Escherichia coli and Salmonella spp from food-producing animals and products Authors: Caniça, Manuela; Jones-Dias, Daniela; Francisco, Ana Patrícia; Manageiro, Vera; Ferreira, Eugénia Abstract: Background: Salmonella and Escherichia coli resistant to quinolones frequently arise in animals, being easily transferred to humans through the food chain, which can ultimately lead to the development of untreatable infectious diseases. The aim of the present study was to investigate the presence of PMQR determinants among Salmonella spp and E. coli from food-producing animals and derivative food products. Methods: Salmonella spp (n=183) and E. coli (n=182) isolates were collected from food-producing animals (n=274) and derivative food products (n=91). Antimicrobial susceptibility testing was performed by standard disk diffusion method, according to the CA-SFM veterinary guidelines. PCR and sequencing were used to detect PMQR- (qnrA, qnrB, qnrC, qnrD, qnrS, aac(6’)-Ib-cr, and qepA) and β-lactamase-encoding genes (blaTEM, blaSHV, blaOXA and ampC) and to examine the QRDR of gyrA, gyrB, parC and parE genes in PMQR positive isolates. Plasmid characterization was accessed by conjugation followed by replicon-typing. Genetic relatedness of PMQR positive E. coli was examined by MLST and Salmonella isolates were serotyped according to the Kauffmann-White scheme. Mobile genetic elements were also investigated through PCR mapping assays. Results: Overall, 4.7% (17/365) harbored Qnr-encoding genes from qrnB and qnrS families, specifically qnrB2 (n=3), qrnB19 (n=3), and qnrS1 (n=11). All but one isolate presented at least one mutation in QRDR region of genes gyrA, parC or parE genes. 35.3% of Qnr-producing isolates presented resistance to β-lactam antibiotics that were justified by the presence of β-lactamases from TEM (TEM-1, n=10; and TEM-135, n=1) and SHV (SHV-108, n=1) families in QnrB19- and QnrS1-harbouring isolates. All but one Qnr-producing isolates were positively typed by replicon-typing, varying among IncN (n=2), IncFIB (n=11), IncFIC (n=3), IncI1 (n=2), IncHI2 (n=5), IncY (n=1) and IncL/M (n=3) and were, mostly, genetic unrelated. Qnr genes were detected nearby several mobile elements like ISEcl2, IS26 and ISCR1. Conclusions: This study illustrated the existence of Qnr-producing E. coli and Salmonella from food-producing animals, associated to specific mobile elements that can mediate their transference between species and among distinct settings. Epidemiology of PMQR mechanisms and the dissemination of plasmids carrying Qnr-encoding genes in veterinary isolates can compromise the efficacy of fluroquinolone treatments in both animals and humans.

Infeção por H. pylori em endoscopia digestiva: evolução da prevalência e perfil clínico

Mon, 01 Oct 2012 00:00:00 GMT

Title: Infeção por H. pylori em endoscopia digestiva: evolução da prevalência e perfil clínico Authors: Almeida, Mónica; Rodrigues, Teresa; Palha, Ana; Oleastro, Mónica; Lopes, Ana Isabel Abstract: Introdução: A diminuição da prevalência da infecção por H. pylori (Hp) tem sido reportada mundialmente, paralelamente à melhoria das condições socio‑económicas. Tanto quanto é do nosso conhecimento, não existem em Portugal estudos de prevalência em crianças sintomáticas submetidas a endoscopia digestiva. Objectivos: Constituíram objectivos deste estudo: avaliar a prevalência da infecção por Hp num período de 10 anos (3 anos representativos) numa amostra da população pediátrica Portuguesa sintomática submetida a endoscopia digestiva; descrever aspectos clínicos associados à infecção na mesma amostra. Métodos: Estudo descritivo e analítico retrospectivo. Efectuada revisão de 359 endoscopias diagnósticas realizadas em 2002, 2006 e 2011 num centro terciário de Gastroenterologia Pediátrica (Lisboa), idade ≤18 anos, com realização de biopsia gástrica, para avaliação da prevalência global de infecção e associação do status Hp com variáveis clínicas, indicações para realização de endoscopia, achados endoscópicos e histológicos. Considerou‑se status Hp(+) se histologia e/ou cultura positivas; status Hp(‑) se histologia e cultura simultaneamente negativas. Estatística: teste Qui‑quadrado, teste Exacto de Fisher; α=0,05. Resultados: A indicação mais frequente para endoscopia foi dor abdominal/ epigastralgias (53.8%); 175 (48,7%) crianças/jovens evidenciaram status Hp(+): 11,4% ≤5anos, 48% 5≤11anos, 40.6% 11≤18 anos. A prevalência média da infecção foi de 57.1% em 2002, 55.5% em 2006 e 41,3% em 2011, sendo a diminuição significativa no último período (p=0,02). Diminuição verificada nos três subgrupos etários, significativa apenas no subgrupo 5≤11 anos (p=0,042). Achados endoscópicos associados ao status Hp(+) VS Hp(‑): esófago normal (p=0,032), nodularidade antral/corpo (p<0,001) e úlcera duodenal (p=0,013); achados histológicos associados ao status Hp(+) VS Hp(‑): inflamação moderada (p<0,001), actividade ligeira e moderada (p<0,001) e presença de folículos/ agregados linfóides (p<0,005). Conclusões: Contrariamente a estudos efectuados em idêntico contexto noutras populações, constatou‑se uma prevalência ainda elevada da infecção por Hp, sugerindo embora uma tendência recente para a sua diminuição, principalmente em crianças em idade escolar. Alguns achados endoscópicos e histológicos associaram‑se de forma significativa à presença de infecção por Hp. Estes resultados enfatizam a relevância da infecção por Hp na população pediátrica Portuguesa sintomática e a necessidade de adopção de estratégias de abordagem com adequada relação custo‑efectividade

Characterization of Arcobacter butzleri isolates from poultry and slaughterhouse Environment

Thu, 01 Nov 2012 00:00:00 GMT

Title: Characterization of Arcobacter butzleri isolates from poultry and slaughterhouse Environment Authors: Ferreira, Susana; Fraqueza, Maria João; Queiroz, João; Domingues, Fernanda; Oleastro, Mónica Abstract: The genus Arcobacter is an emerging pathogen associated with several clinical symptoms, namely diarrhoea, abdominal pain or bacteraemia. This genus is widely distributed and has been isolated from environmental, animal, food and human samples, being poultry considered the major reservoir. In this study, forty three Arcobacter butzleri strains were isolated from poultry of three flocks from different farms and environment samples at a Portuguese slaughterhouse, also three reference strains were included. All isolates were confirmed at species level by multiplex PCR and genomic DNA fingerprints of all isolates were determined using Pulsed Field Gel Electrophoresis (PFGE) after enzymatic digestion with SmaI and the isolates with undistinguishable SmaI patterns were further analyzed with a second restriction enzyme, SacII. Phenotypic resistance profiles to nine antibiotics were assessed by broth microdilution method. Biofilm formation assays were performed in the 36 out of the 43 A. butzleri isolates, either presenting different pulsetypes or similar PFGE patterns but different origin or even different resistance patterns. PFGE patterns obtained using restriction enzymes SmaI and SacII revealed genetic diversity, with 32 distinct PFGE patterns. A high percentage of A. butzleri isolates was found to be resistant, recording four different resistance profiles. Twenty four of the 43 isolates presented a phenotypic resistance to ciprofloxacin, in contrast to the great susceptibility against gentamicin and chloramphenicol. Among the 36 selected A. butzleri isolates, 13.9% were categorized as moderately adherent, while 58.3% were defined as weakly adherent. Overall, the results showed a high degree of genetic heterogeneity among A. butzleri isolates, along with high levels of resistance to several antibiotics. Biofilm formation ability of A. butzleri can possibly favour dispersion and cross-contamination along the slaughterhouse processing line. These findings may represent a contribution to get insight the survival and even persistence mechanisms of this organism in the environment and on its relevance as a potential hazard for foodborne infections.

Molecular biology versus conventional methods – Complementary methodologies to understand occupational exposure to fungi

Wed, 01 Feb 2012 00:00:00 GMT

Title: Molecular biology versus conventional methods – Complementary methodologies to understand occupational exposure to fungi Authors: Viegas, C.; Malta-Vacas, J.; Sabino, R.