Aline Feola de Carvalho

Detection of CDT toxin genes in Campylobacter spp. strains isolated from broiler carcasses and vegetables in Sao Paulo, Brazil

Campylobacteriosis is a worldwide distributed zoonosis. One of the main virulence factors related to Campylobacter spp. in animals and humans is the cytolethal distending toxin (CDT), encoded by three adjacent genes (cdtA, cdtB, cdtC). The occurrence of Campylobacter spp. in samples of vegetables has not been reported in Brazil yet, and has seldom been described in the international literature. The detection of CDT in these strains has not been reported, either. The objectives of the present study were to determine the occurrence of Campylobacter spp. strains carrying virulence factors in samples of poultry and vegetables (lettuce and spinach) from different points of sale, thus verifying if vegetables are as an important vehicle for potentially virulent Campylobacter spp. strains as poultry. Twenty four strains were identified as Campylobacter jejuni by phenotypic and genotypic methods: 22 from broiler carcasses and two from lettuce samples. Three strains were identified as Campylobacter coli: two from broiler carcasses and one from lettuce. The presence of the cdt genes were detected in 20/24 (83.3%) C. jejuni strains, and 3/3 (100%) C. coli strains. The isolation of Campylobacter spp. strains with the cdt gene cluster in lettuce samples points to a new possible source of contamination, which could have an impact in the vegetable production chain and risk to public health. Results show that potentially virulent C. jejuni and C. coli strains remain viable in samples of broiler carcasses and vegetables at the points of sale.

Detecção dos genes da toxina citoletal distensiva em estirpes de Campylobacter jejuni isoladas de carcaças de frangos

Eighty samples of refrigerated broiler thighs purchased in street markets and supermarkets in the city of Sao Paulo, SP, were analyzed. Thirteen Campylobacter spp. strains were isolated in 10 (12.5%) thighs, five of them from street market samples and other five from supermarkets. Eleven strains were identified as Campylobacter jejuni and two of them as Campylobacter coli. The 11 strains were confirmed to be C. jejuni using PCR for hippuricase (hip) gene. From these, multiplex-PCR showed that four (36.4%) strains presented the three genes (cdtA, cdtB, and cdtC) encoding cytolethal distending toxin: three strains from supermarket and one from street market samples. These results are important, because they demonstrate the presence of virulent C. jejuni strains in refrigerated broiler thigh samples, not only in the slaughterhouse but in the final point of the distribution chain, at the two most important food retail commercer.

Detecção de fatores de virulência em estirpes de Campylobacter spp. isoladas de carcaças de suínos abatidos em frigoríficos

The purposes of this study were to isolate and identify Campylobacter spp. strains from the carcasses (n=65), feces (n=65) and mesenteric lymph nodes (n=65) of swine slaughtered in abattoirs in the State of Sao Paulo and to detect the presence of the cdt gene complex - responsible for the expression of the virulence factor cytolethal distensive toxin - in these Campylobacter spp. strains through Multiplex-PCR. From 195 samples analyzed, Campylobacter spp. was isolated in 31 (15.9%): 29 (93,6%) samples of rectal swab, 1 (3.2%) carcass swab and 1 (3.2%) lymph node sample. The 28 strains of isolated C. coli were positive for CDT toxin genes and the three strains of isolated C. jejuni were negative for these genes. It was also the first time that the cdt gene cluster was detected in strains isolated from swine in the state of Sao Paulo. These findings indicate swine as a potential spreading source of virulent strains of Campylobacter coli, either for slaughterhouse staff or consumers of carcasses and sub products.

Caracterização molecular e fenotípica de estirpes de Escherichia coli produtoras de shiga-toxina (STEC) não-O157 de fezes e carcaças bovinas

In the present study 100 rectal and 100 carcass swabs were collected from bovines at slaughterhouses in Sao Paulo state, and the total of 326 E. coli strains were identified (163 from rectal samples and 163 from carcass samples). All the isolates were submitted to PCR for Stx1 and Stx2 toxin gene detection and all strains were identified as non-O157 and phenotyped by the citotoxicity test in Vero cells. Out of 26 strains that presented only the stx1 gene, 56 that presented only the stx2 gene and 30 that presented both genes, 17 (65.4%), 42 (75%) and 22 (73.3%), respectively, were positive for the citotoxicity test. There was no statistically significant difference among these three toxinotyping profiles and positivity in the citotoxicity test, but the results show high frequency of virulence factor expression of bovine.

Caracterização de estirpes de Campylobacter coli isoladas de carcaças de ovinos e de efluentes de abatedouro do estado de São Paulo

A zoonosis and bacterial disease, campylobacteriosis is responsible for frequent cases of human gastroenteritis worldwide. Campylobacter spp. presents the virulence factor called cytolethal distensive toxine (CDT), responsible for diarrhea and codified by the cdt gene. The aims of this study were: 1) to isolate and identify Campylobacter spp. strains from 102 carcass swabs and 102 rectal swabs of sheep (Ovis aries) and seven samples of wastewater, before and after the disinfection treatment, collected from the abattoir of the state of Sao Paulo; and 2) to detect the presence of cdt gene complex by Multiplex-PCR in strains of Campylobacter spp. Seven strains of Campylobacter coli were isolated and identified by phenotypic and genotypic methods: 4/102 (3.92%) from rectal swabs, 1/102 (0.98%) from carcass swabs and 2/7 (28.5%) from wastewater. From the rectal swab samples 2/7 (28.6%) strains were detected with the cdt gene. This is the first report on the isolation of Campylobacter coli from sheep abattoir, and of strains carrying the cdt gene complex in this animal species in Brazil.

Validação de nova proposta de espermocultura quantitativa aplicada a sêmen industrializado de touros

The Brazilian Ministry of Agriculture (MAPA) has discussed the mandatory culture of industrialized semen, both to ensure biosefety, and to prevent in vitro fertilization problems caused by oocyte contamination with ubiquitous and opportunistic bacteria from preputial microbiota. Pour plate, a quantitative technique recommended by the World Organization for Animal Health (OIE), is operationally difficult and costly for routine analysis in Artificial Insemination Centers (AICs). The objectives of this study were to evaluate and validate viable superficial bacteria counts (VSBC), in CFU/mL, compared with pour plate counts, in industrialized bull semen samples from AICs. Semen straws from Projeto Hungria - MAPA bulls were used. VSBC and pour plate were carried out in parallel in serial dilutions of the samples, from 10-1 to 10-5. CFU/mL means or medians recorded in each dilution and technique were compared, and no statistical differences were observed between the two techniques regarding the quantification of bacteria in CFU/mL, suggesting that it may be possible to replace pour plate for CBSV, a cheaper and more practical technique.

Ocorrência de anticorpos anti-Brucella ovis em ovinos com histórico de distúrbios reprodutivos no estado de São Paulo, Brasil

Based upon a history of reproductive disorders, a serological survey and attempts to isolate Brucella ovis were performed in 28 farms in the State of Sao Paulo, in a total of 294 sheep. The sera sampled on the occasion of the visit to the farms were subject to complement fixation. During clinical examination, samples of several suspicious biological materials were collected for further bacterial culture in Brucella agar medium, in a total of 16 aborted foetuses, one uterus, one placenta, 13 uterine discharge, six vaginal swabs, 17 semen samples and three preputial swabs. The proportion of sheep with a history of reproductive disorders and serum reactive for B. ovis was of 1.7% (5/294), including one ram and four ewes, with titres ranging from 800 IU to 1600 IU. Four of the 28 sheep herds surveyed had serum reactive animals (14,3%). All cultures of biological samples were negative, including semen and swabs from the reproductive organs of a Texel ram, positive in two complement fixation tests, six months apart. In the sheep herds surveyed in the State of Sao Paulo, it was not possible to relate the reproductive disorders to the positive serology for B. ovis, however, foci were detected, representing a risk factor for bacterial dissemination in the herds.