Molecular characterization and antimicrobial resistance profiles of Salmonella Heidelberg isolates from poultry.

In the last 10 years, Salmonella Heidelberg has been extensively isolated from poultry in several countries. In this context, molecular characterization is essential to understand whether the strains have entered the farms from a single or several sources. Thus, the aim of this study was to determine the genetic relationship and antimicrobial susceptibility of S. Heidelberg strains isolated between 2011 and 2012 from broiler farms belonging to three integrated poultry companies located in Argentina. The genetic relatedness of the S. Heidelberg isolates was determined by pulsed-field gel electrophoresis (PFGE), and resistance to 21 antimicrobials was determined by the disc diffusion method. The isolates were assigned to four PFGE patterns. Most of the strains showed 100% similarity and belonged to the same integrated poultry company. This PFGE pattern was also prevalent in S. Heidelberg strains isolated from humans in several provinces of Argentina, which suggests an epidemiological association between human and poultry strains. All the isolates were classified as multidrug-resistant (MDR), and no clear relationship was observed between PFGE and resistance patterns. S. Heidelberg strains may circulate among farms from the same integrated company due to common sources of contamination. To guarantee the safety of the poultry product for the consumers, holistic approaches including surveillance of Salmonella throughout the production chain together with control measures are crucial.

(GTG)5 microsatellite regions in citrinin-producing Penicillium.

Morphological and cultural characteristics, as well as biochemical properties, are the main criteria used in fungal taxonomy and in the standard description of fungi species. Sometimes, however, this criterion is difficult to apply due to fungal phenotypic variations. This is particularly true in the genus Penicillium. The aims of this work were to determine (GTG)5 microsatellite sequence in potentially citrinin-producing Penicillium strains and to investigate if this sequence could be useful to characterize such fungi. Penicillium citrinum Thom and Penicillium chrysogenum Thom were isolated from different foods. The identification of the isolates at species level was carried out according to classical taxonomy. The production of citrinin was determined by thin layer chromatography. This study proved that microsatellite regions exist as short repeated sequences in all tested strains. The patterns were very similar for all P. citrinum isolates and it was possible to group them in function of the quantity of citrinin produced. Yet, not similar clusters were obtained when P. chrysogenum isolates were analyzed.

(GTG)5 microsatellite regions in citrinin-producing Penicillium

Los principales criterios que se utilizan en la taxonomía fúngica, así comoen la descripción de las especies, son sus caracteres morfológicos y decultivo y sus propiedades bioquímicas. Sin embargo, a veces, resulta muydifícil clasificarlos debido a su variabilidad fenotípica, lo que esparticularmente cierto con el género Penicillium.Los objetivos de este trabajo fueron determinar regiones microsatellites (GTG)5en Penicillium potenciales productores de citrinina e investigar la utilidad delas mismas para caracterizarlos.Penicillium citrinum Thom y Penicillium chrysogenum Thom fueron aislados apartir de diferentes alimentos. La identificación de las especies se llevó a caboaplicando las claves taxonómicas clásicas y la producción de citrinina sedeterminó mediante cromatografía en capa delgada.Se demostró la existencia de los microsatélites, como secuencias cortas yreiteradas, en todas las especies estudiadas. Los patrones obtenidos en todaslas cepas de P. citrinum fueron muy similares y permitieron agruparlas segúnla cantidad de toxina producida. Los aislamientos de P. chrysogenum nopudieron ser agrupados de la misma manera(AU)

Morphological and cultural characteristics, as well as biochemical properties,are the main criteria used in fungal taxonomy and in the standard descriptionof fungi species. Sometimes, however, this criterion is difficult to apply due tofungal phenotypic variations. This is particularly true in the genus Penicillium.The aims of this work were to determine (GTG)5 microsatellite sequence inpotentially citrinin-producing Penicillium strains and to investigate if thissequence could be useful to characterize such fungi.Penicillium citrinum Thom and Penicillium chrysogenum Thom were isolatedfrom different foods. The identification of the isolates at species level wascarried out according to classical taxonomy. The production of citrinin wasdetermined by thin layer chromatography.This study proved that microsatellite regions exist as short repeatedsequences in all tested strains. The patterns were very similar for allP. citrinum isolates and it was possible to group them in function of thequantity of citrinin produced. Yet, not similar clusters were obtained whenP. chrysogenum isolates were analyzed(AU)

[Comparison of three microbiological methods for detection of expanded-spectrum betalactamases in Enterobacteriaceae isolated in Santa Fe (Argentina)]. / Comparación de tres métodos microbiológicos para la detección de betalactamasas de espectro extendido en enterobacterias aisladas en Santa Fe (Argentina).

INTRODUCTION: Expanded-spectrum betalactamases (ESBLs) are the main source of resistance to oxyimino cephalosporins and monobactams in Enterobacteriaceae. Most of them derive from TEM or SHV, however the incidence of other families like CTX-M, OXA and PER has increased. In Argentina, the most frequent ESBL in Enterobacteriaceae is CTX-M-2. This specific circumstance, which differs from the situation in the Northern Hemisphere, motivated us to study new diagnostic strategies for the detection of ESBLs in our region. METHOD: Microbiological ESBL detection was performed by double-disk synergy tests, cefotaxime and ceftazidime disks with and without clavulanic acid (NCCLS), and cefotaxime and ceftazidime disks in Müeller-Hinton agar supplemented with lithium clavulanate (MH-cla). Betalactamases were characterized by isoelectric focusing, hydrolysis profile and PCR amplification. RESULTS: Among 575 clinical isolates of Enterobacteriaceae, 14% were oxyimino cephalosporin-resistant. Two different ESBLs were detected in 31 resistant strains: CTX-M-2 (28) and PER-2 groups (3). The double-disk synergy test was the least sensitive method for ESBL detection. ESBLs were detected by the other two methods in all isolates with the use of cefotaxime disks, but not with ceftazidime disks. CONCLUSION: The microbiological method employing MH-cla with cefotaxime disks had a sensitivity and specificity comparable to the referral test using the same antibiotic proposed by the NCCLS for the detection of ESBLs.