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San Michele, Italy

Pasquali F.,University of Bologna | Lucchi A.,University of Bologna | Braggio S.,University of Bologna | Giovanardi D.,Tre Valli Laboratory | And 3 more authors.
Veterinary Microbiology

Escherichia coli is a normal inhabitant of the intestinal tract of chickens, but when an imbalance in the gut microbiota occurs, E. coli may overgrow and cause extraintestinal infections. The aims of this study were to assess the distribution and spread of E. coli isolates with specific phylogenetic groups and antimicrobial resistance characters among asymptomatic breeder flocks and their broiler progenies with early symptoms of colibacillosis. Broiler flocks were treated with lincospectin during the first week of life and sampled at one, 21 and 42 days. The majority of the 363 E. coli isolates belonged to phylogenetic group A (53.17%), followed by groups D (23.14%), B1 (19.28%) and B2 (4.41%). In broilers, group A was the most represented in birds of 21 and 42 days of age whereas group B1 was the most represented phylogroup in one-day old chicks. More than 90.00% of the isolates were resistant to one or more antimicrobials. Along the life-time of broilers, no differences were found on the occurrence of resistant isolates except for the number of E. coli with elevated MIC to spectinomycin, which increased significantly after the lincospectin treatment. According to XbaI-macrorestriction analysis, a high genetic diversity among E. coli isolates was underlined. Four antimicrobial resistant E. coli isolates of phylogroups A, B1 and D collected from breeders showed similar PFGE patterns to five isolates collected from the respective broiler progenies suggesting a potential spread of these isolates from breeders to broilers. © 2015 Elsevier B.V.. Source

Franzo G.,University of Padua | Naylor C.J.,University of Liverpool | Lupini C.,University of Bologna | Drigo M.,University of Padua | And 6 more authors.

Over a period of almost two years, broilers chickens on several hundred Italian farms, were monitored for infectious bronchitis virus. Detections were genotyped using a hypervariable region of the gene coding for the S1 segment of the spike protein. A range of genotypes were detected which comprised QX, Q1, Mass, D274 and 793B. Sequences of 793B viruses detected in chickens, vaccinated with either of the two commonly used 793B type vaccines were almost identical to sequences of one or other of these vaccines. This strong indication of vaccine association led to the withdrawal of live 793B vaccine use on all of the farms of the study. Except for one sample collected soon after 793B vaccination ceased, it was no longer possible to detect 793B vaccine on these farms. It appears that field 793B strains have disappeared from the region of Italy tested thus obviating any need for current vaccine protection against 793B. © 2014 Elsevier Ltd. Source

Giovanardi D.,Tre Valli Laboratory | Lupini C.,University of Bologna | Pesente P.,Tre Valli Laboratory | Rossi G.,Tre Valli Laboratory | And 2 more authors.
Veterinary Research Communications

The aim of this study was to evaluate if the exposure to Avian metapneumovirus (aMPV) and/or to Turkey hemorrhagic enteritis virus (THEV) was significant for the induction of episodes of colibacillosis in aMPV and THEV vaccinated turkeys. Colibacillosis-associated mortality was recorded and longitudinal virological studies performed in three consecutive turkey flocks reared in the same farm. aMPV and THEV diagnostic swabs and blood samples were made once a week up to 14 weeks of age. Swabs were processed by molecular techniques for viruses detection and antibody titres were evaluated. Field subtype B aMPVs were detected in all flocks at different ages of life always associated with respiratory signs and increase of colibacillosis-associated mortality. THEV has been consistently detected in all flocks since the 9th week of age. Vaccination with a single dose of the THEV commercial inactivated vaccine available in Italy seems does not protect the birds from the infection. Sequence comparison of the hexon protein of one of the THEV strains detected, and strains isolated worldwide, revealed high similarity between them. These results are consistent with the notion that the hexon protein, being the major antigenic component of the virus, is highly conserved between the strains. Results showed that field aMPV infection is directly correlated to colibacillosis-associated mortality. Less clear appears the role of THEV because the endemicity of aMPV makes difficult to evaluate its role in predisposing colibacillosis in absence of aMPV. It would be interesting to further investigate this issue through experimental trials in secure isolation conditions. © 2014 Springer Science+Business Media. Source

Listorti V.,University of Bologna | Lupini C.,University of Bologna | Cecchinato M.,University of Padua | Pesente P.,Tre Valli Laboratory | And 4 more authors.
Avian Pathology

Live vaccines predominantly control avian metapneumovirus (aMPV) infection in poultry flocks, but vaccine virus can be found for extended periods after application. The most frequently used aMPV vaccine in Italy, VCO3 subtype B, was shown to contain a unique Tru9I restriction endonuclease site within the amplicons produced by a commonly used aMPV diagnostic reverse transcriptase (RT)-nested polymerase chain reaction (PCR). Analysis of European and database logged subtype B aMPV sequences confirmed that the sequence occurred only in the VC03 vaccine. A subsequent RT-PCR restriction endonuclease study of field samples, collected from turkeys between 2007 and 2012, detected subtype B vaccine-derived strains in 12 of 90 samples tested that were collected from birds under 12 weeks of age. © 2013 Houghton Trust Ltd. Source

Giovanardi D.,Tre Valli Laboratory | Lupini C.,University of Bologna | Pesente P.,Tre Valli Laboratory | Rossi G.,Tre Valli Laboratory | And 2 more authors.
Poultry Science

This study investigated the occurrence of avian pathogenic Escherichia coli (APEC) in a finishing turkey commercial farm, carrying out longitudinal surveys involving 3 consecutive flocks. The diversity and the distribution of the E. coli strains detected during colisepticemia outbreaks were examined. The strains were isolated, serogrouped, assessed for the presence of virulence-associated genes, typed by random amplification of polymorphic DNA (RAPD), and antimicrobial resistance analysis was then carried out. Escherichia coli O78 and O2 were predominantly found. Moreover, based on the somatic antigens used in the study, strains were recovered that were nontypeable. On one occasion, an E. coli O111 strain was found in turkeys. The E. coli isolates differed in terms of antibiotic resistance and RAPD profile. All strains possessed the virulence genes that enabled them to be considered APEC. Strains not only differed between flocks, but also within the same flock. These findings point out the importance of addressing colibacillosis therapy on the basis of a sensitivity test. © 2013 Poultry Science Association Inc. Source

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