Short communication: Detection of stx2 and elt genes in bovine milk by using a multiplex PCR system.

The aim of this study was to detect 2 important toxin genes from diarrheagenic Escherichia coli (DEC) in bovine milk using a new multiplex PCR. To standardize the multiplex PCR, the stx2 and elt genes were investigated for the detection of Shiga toxin-producing Escherichia coli (STEC) and enterotoxigenic E. coli (ETEC), respectively. The DNA template was prepared with a thermal procedure (boiling) and a commercial kit. Samples consisted of UHT and pasteurized milk, both skimmed, and STEC and ETEC were tested in concentrations between 101 and 109 cfu/mL. With the thermal procedure, the multiplex PCR system detected both pathotypes of E. coli at 109 cfu/mL in UHT and pasteurized milk. When the commercial kit was used for template preparation, STEC and ETEC could be detected at concentrations as low as 104 cfu/mL in UHT and pasteurized milk. Negative controls (Listeria monocytogenes, Salmonella Typhimurium, Salmonella Enteritidis, and Escherichia coli strain APEC 13) were not amplified with the multiplex PCR. These results indicate that the multiplex PCR was a rapid (less than 6 h) and efficient method to detect STEC and ETEC in milk using different methods for DNA preparation; however, the commercial kit was more sensitive than the thermal procedure.

Novel multiplex PCR for detection of diarrheagenic Escherichia coli strains isolated from stool and water samples.

Diarrhea is considered the second most common cause of infant mortality worldwide. The disease can be caused by many different pathogens, including diarrheagenic Escherichia coli (DEC), which includes the pathotypes enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enteroaggregative E. coli (EAEC), Shiga toxin-producing E. coli (STEC), and enteropathogenic E. coli (EPEC). To develop a multiplex PCR system for the safe and accurate identification of the five main pathotypes of DEC, seven pairs of primers were determined for the following genes: aaiC, escV, bfpA, ipaH, elt, stx1, and stx2. To validate the system, 413 isolates from different sources (water and both animal and human stool) were analyzed that had been characterized previously. The sensitivity data were grouped by pathotype, in which 92.7% of the atypical EPEC were correlated, as were 92.8% of the STEC, 91.35% of the EAEC, and 100% of the typical EPEC, ETEC, and EIEC. These findings indicate that it is possible to detect the major five pathotypes of DEC from different sources, which can aid in determining the epidemiology of diarrhea with a low cost, high sensitivity and specificity, and the easy and safe viewing of the resulting PCR products.

Antibacterial synergic effect of honey from two stingless bees: Scaptotrigona bipunctata Lepeletier, 1836, and S. postica Latreille, 1807.

Several studies have tested antimicrobial activity of combinations of honey and various substances. In this study, we tested a combination of two stingless bee honeys against various bacterial strains. In particular: the antibacterial activity of honeys produced by Scaptotrigona bipunctata (SB) and Scaptotrigona postica (SP) was evaluated against Gram-positive and Gram-negative bacterial strains by agar well diffusion assays, minimum inhibitory concentration (MIC) assessment, construction of growth and viability curves and scanning electron microscopy (SEM). The interaction of the two honeys was also evaluated by the checkerboard assay. Inhibition zones ranged from 8 to 22 mm. The MIC values of the individual honeys ranged from 0.62 to 10% (v v(-1)) and decreased to 1/4 to 1/32 when the honeys were combined. SEM images showed division inhibition and cell wall disruption for the SB and SP honeys, respectively, and these alterations were observed in same field when the SB and SP honeys were combined. This study demonstrated that the natural honeys possess in vitro antimicrobial activity against Gram-positive and Gram-negative bacteria, including multidrug-resistant strains. Combination of the SB and SP honeys could lead to the development of new broad-spectrum antimicrobials that have the potential to prevent the emergence of resistant bacterial strains.

Classificação dos graus de lesões de aerossaculite em perus associadas com enterobactérias / [Classification of the levels of the airsacculitis injuries in turkeys associated with Enterobacteriaceae]

Foram padronizados os graus de lesões dos sacos aéreos em perus com aerossaculite, associadas com a presença de isolados de enterobactérias nesses órgãos. Um total de 110 amostras de sacos aéreos de perus machos com aerossaculite foi coletado para o estudo. Durante o processo de abate, as amostras foram coletadas por meio de swabs e submetidas a três métodos de armazenamento (imediato, congelado ou pré-incubado após congelamento) para posterior comparação das suas eficiências de isolamento. Os gêneros da família Enterobacteriaceae foram identificados pelas séries bioquímicas EPM, MILi e citrato de Simmons. O crescimento bacteriano ocorreu em 43,64% das amostras. Neste estudo, quatro padrões de lesões de aerossaculite foram identificados de acordo com as características patológicas dos sacos aéreos. Os principais gêneros de enterobactérias identificadas foram: Escherichia coli, Citrobacter, Proteus, Edwardsiella, Morganella, Kluyvera, Salmonella e Klebsiella. Foi observado que os graus padronizados como 3 e 4 apresentaram maior variedade de gêneros bacterianos. O armazenamento imediato apresentou maior porcentagem de positividade, 41,82%, no entanto o pré-incubado após congelamento se apresentou mais eficaz em relação à quantidade de colônias.(AU)

The degrees of air sac lesions in turkeys with airsacculitis were standardized, associated with the presence of Enterobacteriaceae isolated from these organs. A total of 110 samples of air sacs from male turkeys with airsacculitis were collected and analyzed. During the slaughtering process, the sample collection was done using swabs and submitted to three storage methods (immediate, frozen, or pre incubated after freezing) for further comparison of their isolated efficiency. The bacterial genera of the family Enterobacteriaceae were identified biochemical series EPM, MILi and Simmons citrate. Bacterial growth occurred in 43.64% of samples. In this study, four patterns of aerossaculitis lesions were identified according to the pathological characteristics of air sacs. The frequencies of the Enterobacteriaceae isolated identified in the samples were: Escherichia coli, Citrobacter, Proteus, Edwardsiella, Morganell, Kluyvera, Salmonella and Klebsiella. Otherwise, it was observed that the levels already standardized as level three and four showed higher variety of genus. The immediate storage showed higher percentage of positivity at 41.82%, however, the pre incubated after freezing showed more efficiency in relation to the quantity of colonies.(AU)

Antimicrobial resistance, diarrheagenic and avian pathogenic virulence genes in Escherichia coli from poultry feed and the ingredients / Resistência antimicrobiana, genes de virulência diarreiogênicos e patogênicos para aves em Escherichia coli isoladas de ingredientes e ração de frangos

Diarrheagenic (DEC) and avian pathogenic Escherichia coli (APEC) are associated with intestinal and extra-intestinal infections (ExPEC), respectively. We aimed to analyze the antimicrobial susceptibility, gene encoding virulence factors associated to DEC and APEC, and phylogenetic classification in E. coli isolated from 320 samples of feed and ingredients. Antimicrobial susceptibility was performed using the disk diffusion method and Multiple Antibiotic Resistance (MAR) Index and Multi-Drug Resistance (MDR) were calculated. Phylogenetic classification was performed on samples harboring DEC and/or APEC virulence-associated genes. A total of 110 E. coli strains were isolated in 15% (49/320) of the evaluated inputs (n=13 vegetable meal; n=33 animal meal, n=3 feed). In general, the isolates showed the highest rates of antimicrobial resistance to sulfonamide and cefazolin and 18% (20/110) were multi-drug resistant. MAR index of feed samples was the highest (0.467). Six and five strains had APEC and DEC virulence-associated genes, respectively, and belonging to phylogenetic groups A and B1. These findings point to the need for strict microbiological control during the production process of these foods.(AU)

Escherichia coli diarreiogênicas (DEC) e patogênicas para aves (APEC) são associadas a infecções intestinais e extraintestinais (ExPEC), respectivamente. O objetivo do presente trabalho foi avaliar a sensibilidade antimicrobiana, a presença de genes que codificam os fatores de virulência relacionados à DEC e APEC, e a classificação filogenética em E. coli isoladas de 320 amostras de ração para frangos e ingredientes. A sensibilidade antimicrobiana foi determinada pelo método disco-difusão e calculou-se o índice de resistência múltipla aos antimicrobianos (IRMA) e a resistência a múltiplas drogas (MDR). Nas amostras que possuíam genes de virulência relacionados à DEC e/ou APEC, foi realizada a classificação filogenética. Foram isoladas 110 amostras de E. coli em 15% (49/320) dos insumos avaliados (n=13 farelos vegetais; n=33 farinhas de origem animal; n=3 rações). De forma geral, os isolados apresentaram as maiores frequências de resistência antimicrobiana à sulfonamida e à cefazolina e 18% (20/110) foram resistentes a múltiplas drogas. O IRMA das rações foi o mais alto (0,467). Os genes que codificam fatores de virulência associados à APEC e DEC foram detectados em seis e cinco isolados, respectivamente, pertencentes aos grupos filogenéticos A e B1. Os resultados demonstram a necessidade de rigoroso controle microbiológico durante o processo de produção desses alimentos.(AU)

Efeito de dietas contendo plasma sanguíneo desidratado sobre características microbiológicas, imunológicas e histológicas de leitões leves ao desmame / Effect of spray-dried plasma diets on microbiological, immunological and histological parameters of light weight weaned pigs

Foram avaliados os efeitos do plasma sanguíneo desidratado (PSD) sobre desempenho, perfil imunológico, histológico, microbiológico e peso de órgãos de leitões leves, desmamados aos 21 dias de idade. Foram utilizados 24 leitões, com idade média inicial de 21 dias, em delineamento experimental completamente ao acaso. Os tratamentos foram: T1 - animais pesados ao desmame, sem suplementação com PSD; T2 - animais leves ao desmame, suplementados com 10g/animal/dia de PSD; T3 - animais leves ao desmame, suplementados com 20g/animal/dia de PSD; T4 - animais leves ao desmame, sem suplementação com PSD. A adição de 20g de PSD na dieta melhorou o ganho diário de peso, aumentou o peso (g/kg) do baço e o título de IgA no soro entre 21 e 31 dias de idade. A inclusão de 10g de PSD aumentou o comprimento e a largura do linfonodo ileocólico. A inclusão de PSD traz benefícios aos leitões nos primeiros 10 dias pós-desmame, atuando principalmente nos órgãos linfoides e na mucosa intestinal.

The aim of this experiment was to evaluate the effects of spray-dried plasma (SDP) on the growth performance, immunological, histological and microbiological profile and weight of organs of light weight weaned pigs. The trial was done using 24 pigs with an initial mean age of 21 days in a completely randomized experimental design. The treatments were: T1 - heavy weight weaned pigs, without SDP supplementation; T2 - light weight weaned pigs, supplemented with 10g/animal/day of SDP; T3 - light weight weaned pigs, supplemented with 20g/animal/day of SDP; T4 - light weight weaned pigs, without SDP supplementation. The inclusion of 20g of SDP in the diet improved the weight gain, spleen weight (g/kg) and serum IgA title between 21 and 31 days of age. The inclusion of 10g of SDP in the diet improved the length and width of the ileocolic lymph node. In the first 10 days after weaning, SDP improved the development of lymphoid organs and the protection of the intestinal mucosa.