Gisele Veneroni Gouveia

Pitiose em ovinos nos estados de Pernambuco e Bahia

Pythiosis is a devastating infectious disease caused by an aquatic oomycete, Pythium insidioum, and affects animals and humans that inhabit wetlands. The disease is characterized mainly by granulomatous lesions in the hosts. The purpose of this study was to report the occurrence of pythiosis in sheep in the states of Pernambuco (PE) and Bahia (BA), Northeastern Brazil, as well as to evaluate the efficacy of an immunotherapic against ovine pythiosis. Blood samples were collected from 53 sheep, 49 from flocks in counties located in PE and four from BA. Seven sheep showed clinical signs of ovine pythiosis; one of them was submitted to euthanasia and its head and submandibular lymph node was collected and sent for histopathologic and mycological analyses. Other six sheep were treated with an immunotherapic. During the treatment the animals were kept in the Sheep Industry Sector facilities at Univasf/Petrolina-PE. ELISA, fungal culture and polymerase chain reaction (PCR) methods were used to confirm the diagnosis of clinical ovine pythiosis in the sheep flock. At microscopic examination of the material collected from the nasal cavity of a sheep euthanized was observed a focally extensive area of necrosis with presence of diffuse infiltration of intact and degenerated neutrophils bordering the cartilage. Only one sheep showed clinical cure, indicating efficiency in the pythiosis treatment of 16.7% (1/6). Ovine pythiosis has been increasing in several municipalities of PE and BA. In this context, the immunotherapy may be an alternative to be searched. Therefore, further studies are needed to investigate the effect of immunotherapy on ovine pythiosis.

Distribution of PLD and FagA, B, C and D genes in Corynebacterium pseudotuberculosis isolates from sheep and goats with caseus lymphadenitis

Caseous lymphadenits (CL) is a chronic and subclinical disease that affects goats and sheep and, consequently, causes economic losses, especially to small producers. The purpose of this study, through use of Polymerase Chain Reaction (PCR), was to verify the presence of virulence genes of phospholipase D (PLD), integral membrane protein (FagA), iron enterobactin transporter (FagB), ATP binding cytoplasmic membrane protein (FagC) and iron siderophore binding protein (FagD) in 168 isolates of C. pseudotuberculosis obtained from cases of caseous lymphadenitis in goats and sheep. FagA, FagB and PLD genes were detected in all 145 strains isolated from abscesses in superficial lymph nodes and in 23 strains isolated from viscera. The FagC gene was positive in 167 (99.40%) isolates. The FagD gene was detected in 160 (95.23%) isolates. All virulence factors analyzed were found more frequently among isolates collected in the viscera of animals with CL, indicating a multifactorial nature, as well as variations, in the invasive potential of C. pseudotuberculosis strains.

Environmental factors on virulence of Aeromonas hydrophila

Aeromonas hydrophila are known for being opportunistic pathogens, harboring various virulence factors and triggering lesions and death in fish. The disease caused by bacteria can make fish inappropriate for human consumption, besides representing a risk to public health. The pathogenesis can be influenced by environmental variables, affecting fish productivity and mortality. The present study aimed to determine whether A. hydrophila harbor the virulence genes aerolysin, hydrolipase, elastase, lipase, cytotonic enterotoxin (ast), lateral flagellum (laf), and polar flagellum (fla) and to evaluate the influence of environmental variables on in vitro growth, in vivo virulence and expression of some of these genes. Polymerase chain reaction (PCR)-based screening for the presence of these virulence genes was performed on 35 isolates. Six isolates containing different profiles of virulence genes were tested for in vitro growth under different conditions of pH, temperature, and ammonia and for in vivo virulence under these same environmental conditions. RT-qPCR was used to quantify the expression of aerolysin, lipase, and fla genes. All the tested environmental factors influenced the growth of A. hydrophila, while pH and ammonia concentrations influenced the bacterial virulence. The expression of the fla gene increased when bacteria were grown in higher ammonia concentration. The mortality established by Aeromonas is influenced by several environmental factors pinpointing the importance of its control in fish farming to avoid higher economic loses associated to bacterial disease outbreaks.

Virulence Factors in Staphylococcus aureus and Quality of Raw Milk from Dairy Cows in a Semiarid Region of Northeastern Brazil

Background: Milk quality is considered unsatisfactory in Brazil due to factors of a social, economic, cultural, and climatic nature. Mastitis is the main disease that affects dairy herds. Microorganisms of the genus Staphylococcus are the most frequently isolated pathogens in cases of mastitis in bovines. Staphylococcus aureus requires more attention because they have the ability to develop resistance to antimicrobials used in the treatment of mastitis. Thus, the aim of the present study was to evaluate virulence factors in isolates of S. aureus as well as analyze the hygienic-sanitary quality of raw milk produced on dairy farms in a semiarid region of northeastern Brazil. Material, Methods & Results: Samples were taken from milk containers at 44 properties. Fifty-eight isolates of Staphylococcus spp. were analyzed and genotypically identified as S. aureus. In the phenotypic characterization, 56.8% (33/58) of the isolates demonstrated moderate biofilm production. In the genotypic characterization (icaA, icaD and bap genes), icaA was the most representative among the isolates. No resistance to cephalothin or oxacillin was found, but 62% (36/58) of the isolates exhibited resistance to ampicillin, amoxicillin, and penicillin. In the genotypic evaluation in response to β-lactam antibiotics, 50% (29/58) of the isolates exhibited the blaZ gene. Total bacterial counts were determined based on the standard plate count and flow cytometry, for which a significant positive correlation was found (r = 0.61, P < 0.01). The somatic cell count was also performed using flow cytometry and demonstrated that 6.8% (3/44) of the properties had values above one million cells per mL. The analysis of Staphylococcus spp. revealed that 20% (9/44) of the properties had significant counts for the production of staphylococcal enterotoxins. Regarding total coliforms, 56.8% (25/44) of the milk analyzed had counts above 1.0 x 103 CFUs/mL. There were no cases of the isolation of Pseudomonas spp. Streptococcus spp. was isolated on 6.8% (3/44) of the properties. The results of the sequencing revealed one isolate to be Lactococcus lactis and two to be Enterococcus spp. Discussion: None of the 58 isolates of S. aureus was classified as negative in the phenotypic characterization of biofilmforming capacity, which suggests the presence of genes involved in this process. Studies have shown that the molecular techniques used to identify ica genes encoding biofilm synthesis are very important for the identification of virulent strains. The isolates demonstrated resistance to β-lactam antibiotics of the class of penicillins, which are the most widely employed antimicrobial agents for the treatment of diseases in dairy herds. The presence of the blaZ gene in 50% of the isolates is in agreement with data reported in other studies developed in northeastern Brazil. In 50% (29/58) of the isolates, the presence of the blaZ gene was not observed. Of these, (8/29) were resistant to ampicillin, amoxicillin and penicillin. This is due to the existence of other bacterial mechanisms. Research has shown that some isolates possessed three mechanisms (blaZ, mecA and msrA) of antimicrobial resistance simultaneously. The results of the quality analyses demonstrate that some properties produce milk of low quality, which underscores the need for management strategies directed at reducing the contamination of the product.