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Junín de los Andes, Argentina

Moredo F.A.,Catedra de Microbiologia | Cappuccio J.A.,National University of La Plata | Insarralde L.,National University of La Plata | Perfumo C.J.,National University of La Plata | And 2 more authors.
Revista Argentina de Microbiologia | Year: 2012

The purpose of this work was to characterize 47 Escherichia coli strains isolated from 32 pigs diagnosed with postweaning diarrhea and tree pigs with edema disease by PCR. Forty two (95.5%) of the strains isolated from diarrheic pigs were characterized as enterotoxigenic E. coli (ETEC) and 2 (4.5%) as Shiga toxin-producing E. coli (STEC). Fourteen (33.3%) ETEC strains were positive for est/estII/fedA genes. The most complex genotype was eltA/estI/faeG/aidA. Strains isolated from pigs with ED were classified as porcine STEC and were stx 2e/aidA carriers. Eleven (25%) strains carried the gene encoding adhesin protein AIDA-I. However, genes coding for F5, F6, F41, intimin and Paa were not detected. The development of vaccines generating antibodies against prevalent E. coli adhesins in Argentina could be useful for the prevention of PWD and ED. Source


Malassezia are lipophilic yeast, commensal organisms of human and animal skin. The yeast has often been isolated from otitis externa cases as the most common organism and complicating factor. The purpose of this study was to evaluate the effectiveness of cytology as a diagnostic methodology in canine external otitis in Corrientes City (Argentina). Samples from the auditory tube of 95 dogs with otitis and from 95 healthy dogs were obtained. Sterile cotton swabs were used to collect specimens from the external ear canal and then cultured in agar Sabouraud and modified Dixon's agar. Cytological examinations were performed to detect the presence and population size of Malassezia yeast. Each swab was rolled on a clean glass slide and stained with Gram Kopeloff. Ten fields were examined microscopically using an oil immersion objective (1000x magnification). The isolation of M. pachydermatis in dogs with external otitis (70.52%), in relation to the healthy animals (28.42%) was significant (p<0.05). The agreement between cytological results and fungal cultures were also statistically significant. The performance of the cytological examination and the culture showed a sensitivity around 75.79% and 70.53%; specificity was 50.53% and 71.58%; whereas predictive values were 60% and 70%, respectively. Cytological examination of otic exudate confirms Malassezia overgrowth. In the present investigation the results indicated that ≥ 10 yeast count per high-power fields (oil immersion objective) allows to identify and characterize the microbial infection. Nevertheless, considering the test sensitivity and low specificity obtained attributable to the unequal distribution of yeast observed in the healthy population, it is necessary to use two or more simultaneous techniques to detect Malassezia, determine the medical significance, and confirm infection. Source


Binetti A.,CONICET | Carrasco M.,Catedra de Microbiologia | Reinheimer J.,CONICET | Suarez V.,CONICET
Journal of Applied Microbiology | Year: 2013

Aims: The aim of this work was to identify 20 yeasts isolated from autochthonal cheese starters and evaluate their technological and functional properties. Methods and Results: The capacities of the yeasts to grow at different temperatures, pH, NaCl and lactic acid concentrations as well as the proteolytic and lipolytic activities were studied. Moreover, survival to simulated gastrointestinal digestion, hydrophobicity, antimicrobial activity against pathogens and auto- and co-aggregation abilities were evaluated. The sequentiation of a fragment from the 26S rDNA gene indicated that Kluyveromyces marxianus was the predominant species, followed by Saccharomyces cerevisiae, Clavispora lusitaniae, Kluyveromyces lactis and Galactomyces geotrichum. RAPD with primer M13 allowed a good differentiation among strains from the same species. All strains normally grew at pH 4·7-5·5 and temperatures between 15 and 35°C. Most of them tolerated 10% NaCl and 3% lactic acid. Some strains showed proteolytic (eight isolates) and/or lipolytic (four isolates) capacities. All strains evidenced high gastrointestinal resistance, moderate hydrophobicity, intermediate auto-aggregation and variable co-aggregation abilities. No strains inhibited the growth of the pathogens assayed. Conclusions: Some strains from dairy sources showed interesting functional and technological properties. Significance and Impact of the Study: This study has been the first contribution to the identification and characterization of yeasts isolated from autochthonal cheese starters in Argentina. Many strains could be proposed as potential candidates to be used as probiotics and/or as co-starters in cheese productions. © 2013 The Society for Applied Microbiology. Source


Garca-Fulgueiras V.,University of the Republic of Uruguay | Bado I.,University of the Republic of Uruguay | Mota M.I.,University of the Republic of Uruguay | Mota M.I.,Laboratorio Central del Hospital Pereira Rossell | And 7 more authors.
Journal of Antimicrobial Chemotherapy | Year: 2011

Objectives: To analyse the prevalence of resistance to β-lactams and plasmid-mediated quinolone resistance in Enterobacteriaceae in the paediatric hospital of Uruguay. Methods: A total of 368 enterobacterial isolates collected between 1 May and 30 November 2009 were studied for the presence of extended-spectrum β-lactamases (ESBLs), qnr alleles and aac(6')Ib by phenotypic and molecular methods. The genomic context and transferability of β-lactamase and qnr genes were examined by PCR and conjugation, respectively. Results: The proportion of inpatients having an infection caused by ESBL-producing enterobacteria was 0.23% (16/7073) in paediatrics wards, 0.64‰ (3/4696) in the neonatology department and 0.03‰ (1/32 557) in the emergency department. ESBL-carrying enterobacteria constituted a total of 21.6% (16/74), 13% (3/23) and 0.37% (1/271) when samples were obtained from paediatrics wards, the neonatology department and the emergency department, respectively. Overall, CTX-M-2 (n=7), CTX-M-9 (n=3), CTX-M-8 (n=2), CTX-M-15 (n=1), SHV-5 (n=5) and SHV-2 (n=2) β-lactamases were detected. Thirteen out of 20 ESBL-producing isolates also carried the aac(6')Ib gene, and the cr variant was detected in one of them. qnr alleles were detected in four isolates comprising two qnrA1 genes, a qnrB8-like variant and a new qnrB gene showing 26 amino acid differences from QnrB1. Conclusions: The proportion of ESBL-producing enterobacteria in Uruguay's paediatric hospital during the study period was 2.3 per 1000 hospitalized patients. The number of different microorganisms detected, as well as the various EBSLs, suggests the occurrence of sporadic episodes instead of nosocomial outbreaks. Nevertheless, the presence of new resistance genes reinforces the necessity for permanent surveillance programmes. © The Author 2011. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. Source


Garmendia G.,Catedra de Microbiologia | Vero S.,Catedra de Microbiologia
International Journal of Food Microbiology | Year: 2016

Ochratoxin A (OTA) is a nephrotoxic mycotoxin which has been found worldwide as a contaminant in wines. It is produced on grapes mainly by molds from Aspergillus section Nigri. This study has demonstrated for the first time the occurrence of black aspergilli on Tannat grapes from Uruguay, in a two year survey. Aspergillus uvarum (uniseriate) and Aspergillus welwitschiae (from Aspergillusniger aggregate) were the prevalent species whereas Aspergillus carbonarius which is considered the main OTA producing species was not detected. OTA production in culture medium was evaluated for native isolates from A. niger aggregate and compared to levels produced by a type strain of A. carbonarius. This work also includes the development of quick and easy molecular methods to identify black aspergilli to species level, avoiding sequencing. © 2015 Elsevier B.V. Source

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