Virulence genes and resistance profile of Escherichia coli isolated in meat meal samples

Feed is the main route of transmission of pathogenic microorganisms and is responsible for a large part of the cost of poultry production, so the inclusion of alternative foods in diets for monogastrics has been a constant. Among alternative foods most used in modern poultry farming are animal meal, however, when contaminated they constitute a route of transmission of several pathogenic agents, including Escherichia coli. In addition, there is a zoonotic potential, as poultry products are intended for human consumption. The objective of this research was to detect virulence genes, as well as to evaluate the resistance profile of Escherichia coli isolates from meat meal samples. A total of 40 Escherichia coli isolates were analyzed and the virulence genes surveyed iss, ompT, hlyF, iutA, and fimA identified by Polymerase Chain Reaction (PCR). The antimicrobial agents tested were: amoxycillin (30 µg), ceftiofur (30 µg), ciprofloxacin (5 µg), doxycycline (30 µg), florfenicol (30 µg), fosfomycin (200 µg), gentamicin (10 µg), norfloxacin (10 µg) and oxacillin (1 µg). It was possible to observe the occurrence of the iss resistance gene in 100% of Escherichia coli isolates, followed by hlyF (85%), fimA (75%), ompT (17.5%) and iutA (5%). Regarding the simultaneous detection for the genes, a greater association between the genes iss, hlyF and fimA (60%) was verified. All isolates showed resistance to oxacillin (100%), followed by doxycycline (25%), amoxicillin (22.5%), norfloxacin (17.5%), ceftiofur (15%), florfenicol (12.5%), fosfomycin (12.5%), ciprofloxacin (10%) and gentamycin (2.5%). In this study, a variation of the multiple antimicrobial resistance index (IRMA) was observed between 0.22 and 0.77. The indiscriminate use of of antimicrobials as performance enhancers in production animals, may have contributed to the increase in antimicrobial resistance, with the occurrence of multiresistant Escherichia coli carrying virulence genes. Virulence genes present in Escherichia coli isolates are studied to understand the degree of influence they exert in the establishment of the disease, one of the most researched genes is the iss gene, involved in the processes that promote serum resistance. In this study, iss (100%) was present in all the isolates analyzed, although it is not the only mechanism used by these bacteria to reach internal organs and trigger an infection, this gene encodes an important mechanism associated with high levels of virulence. The second highest prevalence found was of the hlyF gene (85%), the high prevalence of hlyF suggests virulence potential, involved with the production of hemolysin and improvement of outer membrane vesicles associated with the release of toxins. The fimA gene (75%) was detected in a slightly lower percentage when compared to iss and hlyF. With the second lowest prevalence, the ompT gene (17.5%), is involved in a process that includes the proteolytic degradation of antimicrobial peptides and with the lowest prevalence the iutA gene (5%). Certain combinations of virulence genes make the strains easier to survive, adhere to, colonize and even the ability to develop septicemic conditions. Multiresistant E. coli strains, is a fact of concern for both animal and human health, since the presence of multiresistant strains, originating from poultry, can be transmitted from chicken carcasses. In this sense, the importance of sanitary control of the inputs used in animal feed is emphasized, as well as the prudent use of antimicrobials in animal production, with a view to producing a safe food, minimizing not only the economic losses, but also the risks to human health.(AU)

Zinc, manganese and copper amino acid complexed in laying hens' diets affect performance, blood parameters and reproductive organs development.

In the intestinal lumen, excess of oxides and sulfates interfere with the absorption of minerals due to competition from the same absorption site. Amino acids-mineral complexed (AACM) is intended to minimize these problems, which might be absorbed by different absorption sites. Then, a study including Zinc (Zn), Manganese (Mn) and Copper (Cu) from different sources was carried out to evaluate the performance, blood parameters and reproductive organs development of Brown Laying Hens. A total of 800 Lohmann Brown Lite were fed, from one-day-old to 182-days-old, Zn, Mn and Cu from different sources. Measurements were made from 105 to 182-days-old. The laying hens were distributed according to a completely randomized design with 20 replicates and 20 birds per experimental unit. The treatments consisted of a diet supplemented with 70, 70 and 8 mg/kg of Zn, Mn and Cu; respectively, from inorganic sources (IM). The second treatment contained 40, 40 and 2.75 mg/kg of Zn, Mn and Cu, respectively from IM plus 30, 30 and 5.25 mg/kg of Zn, Mn and Cu; respectively, from AACM sources. Performance and reproductive organs development (oviduct and ovary weight), tibia weight, liver weight, egg output and body weight, and blood variables were evaluated. Data were compared by Student's t-test (P < 0.05). Laying hens fed AACM reached 35% of egg output two days earlier and presented heavier tibia bone than the IM group. Those hens also presented greater oviduct weight, greater hematocrit and greater serum concentration of total leukocytes, erythrocytes, eosinophils, monocytes and the hormones T4 and FSH, than the hens fed IM. The supplementation of AACM in laying hens' diets since one-day-old improves the productive performance from the beginning of egg output to peak production, which is justified by better development of bones and oviduct, hormone production and immune system support.

Identification of Campylobacter fetus subsp. venerealis virulence genes in cervical mucus from cows.

We used the polymerase chain reaction to identify virulence genes in cervico-vaginal mucus samples from cows positive for Campylobacter fetus subsp. venerealis. There was positivity for the pldA, racR, dnaJ, cdtA, and cdtB genes. No samples showed the cdtC, ciaB, cadF, wlaN, and virB11 genes.