ABSTRACT
Los bovinos son el principal reservorio de Escherichia coli productor de toxina Shiga (STEC); las estrategias para evitar su transmisión se concentran en la planta de faena. El objetivo de este trabajo fue evaluar la calidad higiénico-sanitaria y la frecuencia de detección de STEC en medias reses bovinas de frigoríficos de tránsito provincial. Se procesaron 274 esponjados de media res; en 9 (3,3%) el recuento de E. coli genérico fue marginal, en 4 (1,4%) se aisló E. coli O157, de los cuales 2 fueron caracterizados como stx2c(vh-a)/eae/ehxA, y los otros 2 como no toxigénicos. A partir de una (0,4%) muestra se aisló E. coli no-O157 ONT:H49, stx2a/ehxA/saa. En este trabajo la calidad del producto analizado indica que en la provincia de Tucumán se cumplen las buenas prácticas de manufactura en la faena de bovinos.
Cattle are the main reservoir of Shiga toxin-producing Escherichia coli (STEC), and the strategies to prevent the transmission of these microorganisms are concentrated in the slaughtering plant. The aim of this study was to evaluate the hygienic-sanitary quality and the frequency of detection of STEC in beef carcasses in abattoirs from Tucuman province. Two hundred and seventy four beef carcass sponges were processed; the count of generic E. coli was marginal in 9 (3,3%) of them. Escherichia coli O157 was isolated in 4 (1,4%) samples; 2 of which were characterized as stx2c(vh-a)/eae/ehxA whereas the other 2 were non-toxigenic strains. Non-O157 E. coli ONT:H49, stx2a/ehxA/saa was isolated from 1 sample (0,4%). In this work the quality of the analyzed product indicates that the good practices of manufacture are fulfilled in slaughtering facilities in Tucumán province.
Subject(s)
Animals , Cattle , Abattoirs , Shiga-Toxigenic Escherichia coli , Meat , Argentina , Escherichia coli O157 , Escherichia coli Proteins/analysis , Escherichia coli Infections , Shiga-Toxigenic Escherichia coli/isolation & purification , Meat/microbiologyABSTRACT
Escherichia coli O157 es un patógeno emergente asociado a diarrea, colitis hemorrágica y síndrome urémico hemolítico. Los productos cárnicos constituyen una importante fuente de contaminación con este microorganismo. Los objetivos de este estudio fueron establecer la frecuencia de detección de E. coli O157 en productos cárnicos y media res en la provincia de Tucumán, caracterizar los factores de virulencia de los aislamientos obtenidos, establecer la relación clonal entre cepas regionales mediante electroforesis de campo pulsado y comparar con lo consignado en la base de datos nacional. Desde 2004 hasta 2013 se analizaron 169 muestras de carne picada, 35 embutidos y 216 esponjados de media res. Se identificaron 13 aislamientos de E. coli O157; 6 de ellos fueron O157:H7 productores de toxina Shiga y se caracterizaron como stx2c(vh-a)/eae/ehxA (n = 5) y stx2/eae/ehxA (n = 1); los 7 aislamientos de E. coli O157 no toxigénicos fueron O157:NT(n = 4),O157:NM (n = 1),O157:ND (n = 1) y O157:H16 (n = 1). Los patrones de PFGE fueron diferentes entre sí y de los registrados en la base de datos nacional. Se concluye que existe gran diversidad genética en los aislamientos de E. coli O157 circulantes en nuestra región
Escherichia coli O157 is an emergent pathogen associated with diarrhea, hemorrhagic colitis and hemolytic uremic syndrome. Meat products constitute an important transmission source of this microorganism. The aims of this study were to characterize E. coli O157 isolated from cattle and meat products collected from abattoirs and retail stores, to establish the clonal relatedness among regional isolates and to compare them with those in the national database. Between 2004 and 2013, 169 minced meat, 35 sausage and 216 carcass samples were analyzed. Thirteen E. coli O157 isolates were identified; 6 of which were O157:H7 and characterized as stx2c(vh-a)/eae/ehxA (n = 5) and stx2/eae/ehxA (n = 1). The 7 remaining isolates were non-toxigenic E. coli strains, and serotyped as O157:NT (n = 4), O157:NM (n = 1), O157:ND (n = 1) and O157:H16 (n = 1). The strains yielded different XbaI-PFGE patterns. Compared to the E. coli O157 isolates in the National Database, none of these patterns have been previously detected in strains of different origin in Argentina
Subject(s)
Animals , Cattle , Escherichia coli O157/isolation & purification , Escherichia coli O157/genetics , Meat Products/analysis , Databases, Bibliographic/statistics & numerical data , Electrophoresis, Gel, Pulsed-Field/methods , Escherichia coli O157/classification , Virulence Factors/analysisABSTRACT
En equipamientos industriales la persistencia de las bacterias se debe al desarrollo de biofilms. El hipoclorito de sodio (NaClO) es usado rutinariamente como desinfectante. El objetivo del trabajo fue determinar el efecto inhibitorio del NaClO sobre S. cohnii productoras y no productoras de biofilms aisladas de una fabrica de pastas a partir de maquinarias de un establecimiento de Tucuman, Argentina. Se estudio produccion de biofilm, concentracion inhibitoria minima (CIM), concentracion bactericida minima (CBM) y curva de tiempo de muerte con NaClO frente a S. cohnii productora y no productora de biofilm. Los resultados obtenidos demostraron que de los ocho cocos grampositivos aislados, cuatro correspondieron a S. cohnii. Los valores CIM y CBM para S. cohnii productoras y no productoras de biofilm resultaron entre 0,05 y 0,2 g/dL. Mediante la curva de muerte se determino efecto bactericida observando una disminucion de ≥4 log de ufc (1h) tratado con 0,2 y 0,4% de NaClO. La formacion de biofilm para la cepa no tratada fue de DO: 0,12 y para la cepa tratada DO: 0,07 a las 18 h. Aplicar desinfectantes con amplio espectro de accion es importante, debido a que la eliminacion de bacterias puede prevenir su diseminacion y evitar la formacion de biofilms.
Persistence of bacteria in industrial equipment is favoured by biofilm formation. Sodium hypochlorite (NaClO) is routinely used as a disinfectant. The objective of the current study was to determine the inhibitory effect of NaClO on biofilm-producing and non-biofilm-producing S. cohnii strains, isolated from equipment in a fresh pasta factory in Tucuman, Argentina. The following parameters were assayed: production of biofilm, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and NaClO death curves for both biofilm-producing and non-biofilm-producing S. cohnii strains. Four of the eight isolated Gram-positive cocci corresponded to S. cohnii. MIC and MBC values for biofilm-producing and non-biofilm-producing S. cohnii strains were between 0.05 and 0.2 g/dL. A bactericidal effect of 0.2 and 0.4% NaClO for 1 h was established with the death curve, showing a decrease in cfu of ≥4 log units. Biofilm production after 18 h for untreated strains gave an OD of 0.12, whereas the OD of treated strains was 0.07. The use of broad spectrum disinfectants is important, because elimination of bacteria helps prevent their propagation and avoid the formation of biofilms.
A persistência da bactéria em equipamento industrial e resultado do desenvolvimento de biofilmes. O hipoclorito de sodio (NaOCl) e rotineiramente utilizado como desinfetante. O objetivo do trabalho foi determinar o efeito inibitorio do NaClO sobre S. cohnii produtoras e nao produtoras de biofilmes isoladas de uma fabrica de massas frescas a partir de maquinarias de um estabelecimento de Tucuman, Argentina. Foram estudados: producao de biofilme, concentracao inibitoria minima (CIM), concentracao bactericida minima (CBM) e curva de tempo de morte com NaClO perante S. cohnii produtora e naoprodutora de biofilme. Os resultados obtidos demonstraram que quatro dos oito cocos Gram-positivos isolados corresponderam a S. cohnii. Os valores CIM e CBM para S. cohnii produtoras e nao produtoras de biofilme foram entre 0,05 e 0,2 g/dL. Atraves da curva de morte foi determinado um efeito bactericida observando uma diminuicao de ≥ 4 log de ufc (1h) tratado com 0,2 e 0,4% de NaClO. A formacao de biofilme, apos 18 h, para a cepa nao tratada foi de DO: 0,12, ao passo que para a cepa tratada foi de 0,07. A utilizacao de desinfetantes de amplo espectro de acao e importante, visto que a eliminação de bacterias pode prevenir sua propagação e evitar a formacao de biofilmes.
Subject(s)
Biofilms , Sodium Hypochlorite/toxicity , Staphylococcus/physiology , Argentina , Food Industry , Industry , PastasABSTRACT
INTRODUCTION: Salmonella sp infections have been reported over recent years in hospitals in Argentina and other countries due to multiresistant strains. The aim of this study was to characterize the extended-spectrum β-lactamases in third-generation cephalosporin-resistant strains of Salmonella enterica serovar Oranienburg. METHODS: We studied 60 strains isolated from children with gastroenteritis and/or extraintestinal complications. The antibiotic susceptibility patterns of the isolates were analyzed and the β-lactamases were characterized using phenotyping and genotyping methods. RESULTS: All the strains were resistant to ampicillin, cefotaxime, cefepime and aztreonam and partially susceptible to ceftazidime, thus corresponding well with the resistance phenotype conferred by CTX-M-type β-lactamases. An isoelectric point enzyme (pI = 7.9) was detected in all of the strains, and this was confirmed by PCR as a member of the CTX-M-2 group. CONCLUSIONS: This is the first report of Salmonella enterica serovar Oranienburg producing β-lactamases of the CTX-M-2 group in a pediatric hospital in Tucumán, Argentina.
INTRODUÇÃO: Em recentes anos foram informadas infecções por Salmonella sp em hospitais da Argentina e outros países devido as cepas multiresistentes. O objetivo deste estudo era caracterizar as β-lactamasas de espectro extendido em cepas de Salmonella enterica serovar Oranienburg resistentes às cefalosporinas de terceira geração. MÉTODOS: Nós estudamos 60 cepas obtidas de pacientes com gastroenterites e com complicações extraintestinais. Os padrões de susceptibilidade antibiotica foram estudados em os isolamentos, as β-lactamasas foram caracterizadas por métodos fenotípicos e genotípicos. RESULTADOS: Todas as cepas eram resistentes a ampicillin, cefotaxime, cefepime e aztreonam e parcialmente suscetível a ceftazidime que corresponde bem com o fenótipo de resistência conferido por as β-lactamasas tipo CTX-M. Na totalidade das cepas, se detectou uma enzima de ponto isoelétrico (pI) 7,9, confirmada por PCR como pertencente ao grupo CTX-M2. CONCLUSÕES: Este é o primeiro reporte de Salmonella enterica serovar Oranienburg produtora de β-lactamasa grupo CTX-M2 em um hospital pediátrico de Tucuman, Argentina.
Subject(s)
Child, Preschool , Humans , Infant , Infant, Newborn , Anti-Bacterial Agents/pharmacology , Salmonella enterica/drug effects , Salmonella enterica/enzymology , beta-Lactamases/genetics , Argentina , DNA, Bacterial/genetics , Genotype , Gastroenteritis/microbiology , Hospitals, Pediatric , Microbial Sensitivity Tests , Phenotype , Polymerase Chain Reaction , Salmonella enterica/geneticsABSTRACT
Vibrio cholerae has been sporadically isolated from rivers in Tucumán, Argentina, since the outbreak in 1991. The aim of this study was to determine the environmental reservoir of the bacterium in these rivers, assessing the presence of Vibrio cholerae non-O1 and O1 (the latter both in its viable culturable and non culturable state) and its relationship to environmental physicochemical variables. 18 water samplings were collected in the Salí River (in Canal Norte and Banda) and the Lules River between 2003 and 2005. Physical-chemical measurements (pH, water temperature, electrical conductivity and dissolved oxygen) were examined. Vibrio cholerae was investigated with conventional culture methods and with Direct Immunofluorescence (DFA-VNC) in order to detect viable non culturable organisms. All isolated microorganisms corresponded to Vibrio cholerae non-O1 and non-O139 (Lules 26 percent, Canal Norte 33 percent and Banda 41 percent). The majority was found during spring and summer and correlated with temperature and pH. Non culturable Vibrio cholerae O1 was detected year round in 38 of the 54 water samples analyzed. Application of the Pearson correlation coefficient revealed that there was no relationship between positive immunofluorescence results and environmental physicochemical parameters. Genes coding for somatic antigen O1 were confirmed in all DFA-VNC-positive samples, whereas the virulence-associated ctxA and tcpA genes were confirmed in 24 samples.
Vibrio cholerae tem sido isolado esporadicamente nos rios da Província de Tucumán, Argentina, desde outubro de 1991. O objetivo deste estudo foi localizar os reservatórios nestes rios, identificar a presença de Vibrio cholerae O1 (em estado cultivável e não cultivável) e relacionar a presença desta bactéria com as variações físico-químicos da água. Foram coletadas dezoito amostras de água do rio Salí (nas localidades de Canal Norte e Banda) e do rio Lules, entre 2003 e 2005. Estas foram submetidas a análises físico-químicos como determinação de pH, temperatura, condutibilidade elétrica e oxigênio dissolvido. A presença de Vibrio cholerae foi verificada por métodos de cultivo convencional e por imunofluorescência direta (DFA-VNC). Todos os microrganismos isolados foram não O1 e não O139 (Lules 26 por cento, Canal Norte 33 por cento e Banda 41 por cento). A maioria foi encontrada na primavera e verão, indicando uma relação com a temperatura e pH. Das 54 amostras analisadas por DFA-VNC, 38 Vibrio cholerae não cultivável, foram detectadas em todas as épocas do ano. As amostras positivas foram confirmadas por PCR para o antígeno somático O1 e para os genes de virulência ctxA e tcpA. Coeficiente de correlação de Pearson revelou que não há relação entre os resultados obtidos por imunofluorescência e a variação dos parâmetros físico-químicos.
Subject(s)
Rivers/microbiology , Vibrio cholerae O1/isolation & purification , Water Microbiology , Argentina , Electric Conductivity , Fluorescent Antibody Technique, Direct , Hydrogen-Ion Concentration , Polymerase Chain Reaction , Seasons , TemperatureABSTRACT
The aim of this study was to compare the efficacy of conservation by freezing the strains of Haemophilus influenzae at -20ºC and -70ºC. Skim milk supplemented with glucose, yeast extract and glycerol allowed highest viability of H. influenzae both at -20ºC and -70ºC from the media analyzed. Trypticase soy broth and brain heart infusion broth supplemented with glycerol, allowed excellent recovery. Use of cotton swaps as supporting material, with or without addition of cryoprotective agents, did not modify H. influenzae viability after six months of storage. Concentration of the initial inoculum positively affected viability when stored at -20ºC. Initial concentration did not influence survival after storage at -70ºC. Thawing at room temperature should not exceed 3 h as to get highest survival percentage
Subject(s)
Humans , Cryopreservation/methods , Haemophilus influenzae , Cell Survival , Cryoprotective Agents/pharmacology , Culture Media , Haemophilus influenzae/drug effects , Temperature , Time FactorsABSTRACT
At present, most Neisseria gonorrhoeae testing is done with Beta-lactamase and agar dilution tests with common therapeutic agents. Generally, in bacteriological diagnosis laboratories in Argentina, study of antibiotic susceptibility of N. gonorrhoeae is based on Beta-lactamase determination and agar dilution method with common therapeutic agents. The National Committee for Clinical Laboratory Standards (NCCLS) has recently described a disk diffusion test that produces results comparable to the reference agar dilution method for antibiotic susceptibility of N. gonorrhoeae, using a dispersion diagram for analysing the correlation between both techniques. We obtained 57 gonococcal isolates from patients attending a clinic for sexually transmitted diseases in Tucuman, Argentina. Antibiotic susceptibility tests using agar dilution and disk diffusion techniques were compared. The established NCCLS interpretive criteria for both susceptibility methods appeared to be applicable to domestic gonococcal strains. The correlation between the MIC's and the zones of inhibition was studied for penicillin, ampicillin, cefoxitin, spectinomycin, cefotaxime, cephaloridine, cephalexin, tetracycline, norfloxacin and kanamycin. Dispersion diagrams showed a high correlation between both methods.
Subject(s)
Anti-Bacterial Agents/immunology , In Vitro Techniques , Neisseria gonorrhoeae/immunologyABSTRACT
ß-lactamase activity was studied in Neisseria gonorrhoeae strains. Optimum temperature was found to be 37ºC. The enzyme was inactivated at temperature higher than 60ºC, but remained active during storage at low temperatures (4ºC, -30ºC and -70ºC) for two months. Enzyme activity was observed within a pH range of 5.8-8.0, while the optimum pH was 7.0-7.2. Addition of Ni²+, Fe²+, Fe cube number +, Mn²+ and p-chloromercurybenzoate to the reaction buffer exerced a negative effect upon the activity, whereas Hg²+ and ethylene diamine tetra-acetic acid produced complete inhibition. These results would indicate the presence of -SH groups at the catalytic site of the enzyme.
Subject(s)
Animals , beta-Lactamases/physiology , Neisseria gonorrhoeae/enzymologyABSTRACT
The antibiotic susceptibilities of Neisseria gonorrhoeae isolates obtained from patients attending a clinic for sexually transmitted diseases in Tucuman, Argentina, were determined by the agar dilution method (MIC). 3.5 per cent of the isolates produced ß-lactamase. A total of 96.5 per cent of ß-lactamase negative isolates tested were susceptible to penicilin (MICó2 µgml-1); 14.03 per cent of the tested isolates were resistant to tetracycline (MICó 2 µgml-1), and 98 per cent of the tested isolates were susceptible to spectinomycin (MICó 64 µgml-1). The MICs for 95 per cent of the isolates, tested for other drugs were: ó µgml-1 for cefoxitin, ó0.06 µgml-1 for cefotaxime, ó0.25 µgml-1 for norfloxacin, ó 10 µgml-1 for cephaloridine, ó 10 µgml-1 for cephalexin and ó50 µgml-1 for kanamycin. Antibiotic resistance among N.gonorrhoeae isolates from Tucuman, Argentina, appeared to be primarily limited to penicilin and tetracycline, which has been a general use against gonorrhoeae in Tucuman since 1960. Periodic monitoring of the underlying susceptibility profiles of the N.gonorrhoeae strains prevalent in areas of frequent transmission may provide clues regarding treatment options and emerging of drug resistance.
Subject(s)
Humans , Agar/therapeutic use , Neisseria gonorrhoeae/drug effects , Gonorrhea/therapy , Penicillins/administration & dosage , Tetracycline/administration & dosageABSTRACT
De acuerdo a Kellogg, Neisseria gonorrohoeae en cuatro (4) tipos. Los dos primeros son virulentos (T1 y T2). Se responsabiliza de este efecto a factores de adhesión (fimbria o pili) quienes permiten la colonización. En el presente estudio se pone en evidencia dichos factores por medio de reacción de hemoglutinación. Se trabajó con 89 cepas de aislamientos recientes obtenidas de pacientes con diagnóstico clínico de gonorrea; se utilizó la microtécnica en portaobjetos descripta por Koransky y colaboradores. Los ensayos se realizaron con eritrócitos pertenecientes a distintas especies y tipos sanguíneos. Se demonstró que los resultados no se modifican cuando se varía la procedencia o tipo de glóbulos rojos usados. Paralelamente, con sueros humanos antigonocócicos se efectuó la reacción de inhibición de hemoglutinación (IHA) frente a las cepas aisladas. Se confirma con estas pruebas la presencia de pili
Subject(s)
Humans , Bacterial Adhesion , Erythrocytes , Neisseria gonorrhoeae/physiology , Hemagglutination Tests , Neisseria gonorrhoeae/isolation & purificationABSTRACT
En este trabajo se demuestra que la insulina 10*-9M produce en linfocitos humanos circulantes estimulados por distintas dosis de fitohemaglutinina (PHA) un incremento en la incorporación de timidina*-3H. El efecto máximo de 95% se obtuvo a las menores dosis de PHA, mientras que disminuyó a medida que la concentración del mitógeno aumentaba y desapareció cuando PHA alcanzó la respuesta máxima. Se estudió, además, la acción conjunta del cortisol y la insulina, en concentraciones fisiológicas, sobre linfocitos humanos circulantes estimulados con dos dosis de PHA. Con dosis bajas del mitógeno (1micronl) el cortisol 10*-6M disminuyó la incorporación de timida *-3H a 15%, fenómeno que no pudo ser normalizado por la insulina 10*-10M ni 10*-8M. En cambio, las mismas dosis de insulina antagonizaron la acción inhibitoria del cortisol 10*-8M, concentración que llevó a 53% la incorporación de timidina *-3H por las células. Cuando las células se estimularon con 5 microns de PHA (dosis máxima) la insulina 10*-10M y 10*-8M antagonizó parcialmente la inhibición producida por cortisol 5x10*-8M y 10*-7M, pero no la de cortisol 10*-6M. Estos resultados sugieren que la insulina incrementa la síntesis de DNA en linfocitos estimulados solamente cuando en el medio de cucltivo existen concentraciones mitogénicas subóptimas y que la inhibición de las síntesis de DNA producida por el cortisol puede ser revertida por la insulina, siempre que el efecto inhibitorio sea menor de 50%
Subject(s)
Rats , Animals , Humans , Female , Hydrocortisone/pharmacology , Insulin/pharmacology , Lymphocyte Activation/drug effects , Phytohemagglutinins/antagonists & inhibitors , Adenosine Diphosphate/biosynthesis , Culture Techniques , Diabetes Mellitus/metabolism , Insulin/antagonists & inhibitors , Thymidine/metabolismABSTRACT
En timocitos de ratas adrenoprivas (Ax) y adrenoprivas-diabéticas (AxD) se estudió la presencia de receptores de insulina y la acción de la hormona "in vitro" e "in vivo" sobre el transporte de ácido alfa -aminoisobutírico (AIB). En ambos grupos la insulina "in vivo" incrementó el transporte dee AIB, mientras que "in vitro" no tuvo ningún efecto. El hecho de que los timocitos carecieran de receptores de insulina se correlaciona con la falta de acción "in vitro", mientras que el efecto "in vivo" sugeriría que la hormona ejercería sobre los timocitos de animales adultos un efecto indirecto a través de alteraciones metabólicas