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Vet Microbiol ; 238: 108429, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31648721


Viral haemorrhagic disease (VHD) and colibacillosis are common diseases in rabbits that cause economic losses worldwide. The effect of colibacillosis on the immune response of vaccinated rabbits against rabbit haemorrhagic disease virus (RHDV) was studied. Four groups (G1-G4) were included. G1 was the negative control group; G2 was the RHDV vaccine group; G3 was the E. coli-infected group; and G4 was the E. coli-infected + RHDV vaccine group. The E. coli infection and RHDV vaccination were simultaneously performed, with another previous infection, 3 days before vaccination. At 28 days post-vaccination (PV), the rabbits (G2-G4) were challenged intramuscularly with 0.5 ml of RHDV at a dose of 103 50% median lethal dose (LD50)/rabbit. The rabbits were observed for clinical signs, body weight gain and mortality rates. Tissue, blood, serum, and faecal samples and rectal swabs were collected at 3, 5, 7, 14, 21 and 28 days PV. Significant clinical signs and mortality and a decrease in BW were observed in the infected + RHDV vaccine group. On the 3rd day post-infection (PI), compared with all the other groups, the vaccinated group (G2) had significantly upregulated hepatic tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels; however, the infected + RHDV vaccine group had significantly higher intestinal levels of TNF-α and IL-6 than the other groups. Furthermore, E. coli infection in vaccinated rabbits led to immunosuppression, as shown by significant decreases (P < 0.05) in heterophil phagocytic activity, the CD4+/CD8+ ratio, and HI antibody responses to RHDV and a significant increase in the heterophil to lymphocyte (H/L) ratio. In conclusion, colibacillosis leads to immunosuppression involving a shift in the equilibrium of cytokines and reduced weight gain and mortality in vaccinated rabbits and could be a contributing factor in RHDV vaccination failure in rabbit farming.

Infecções por Caliciviridae/veterinária , Infecções por Escherichia coli/veterinária , Coelhos/imunologia , Vacinação/veterinária , Vacinas Virais/imunologia , Animais , Infecções por Caliciviridae/imunologia , Infecções por Caliciviridae/mortalidade , Citocinas/genética , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/mortalidade , Infecções por Escherichia coli/fisiopatologia , Regulação da Expressão Gênica/imunologia , Vírus da Doença Hemorrágica de Coelhos/imunologia , Coelhos/microbiologia , Coelhos/virologia , Vacinação/normas
J Glob Antimicrob Resist ; 14: 202-208, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29684574


OBJECTIVES: Antimicrobial resistance in Salmonella serotypes has been reported. Integrons play an important role in the dissemination of antimicrobial resistance genes in bacteria. Scarce literature is available on the identification of integrons in Salmonella isolated from broiler chickens. In this study, antimicrobial susceptibility testing and characterisation of class 1 integrons among multidrug-resistant (MDR) Salmonella enterica serotypes in broiler chicken farms in Egypt were performed. METHODS: Antimicrobial susceptibility was determined by the disk diffusion method. PCR was performed to detect antimicrobial resistance genes and class 1 integrons in the tested Salmonella serotypes. Gene sequencing of the variable region of a class 1 integron was performed. RESULTS: Salmonella spp. were detected in 26 (13.5%) of 192 broiler samples, with Salmonella Enteritidis being the most frequently detected serotype, followed by Salmonella Kentucky and Salmonella Typhimurium and other serotypes. A very high resistance rate was observed to trimethoprim/sulfamethoxazole (100%), whilst a low resistance rate was observed to cefuroxime (57.7%). MDR S. enterica isolates displayed resistance to ciprofloxacin and azithromycin. Class 1 integrons were detected in 20 (76.9%) of the 26 Salmonella isolates. A high prevalence of class 1 integrons, as the first recorded percentage in the literature, associated with MDR Salmonella isolates was observed. CONCLUSIONS: Antimicrobial resistance rates in Salmonella serotypes from broiler chicken farms were alarming, especially for ciprofloxacin and azithromycin. Thus, another therapeutic strategy other than antimicrobials is recommended to prevent outbreaks of MDR Salmonella.

Galinhas/microbiologia , Farmacorresistência Bacteriana Múltipla , Integrons , Salmonella/classificação , Animais , Azitromicina/farmacologia , Cefuroxima/farmacologia , Ciprofloxacino , DNA Bacteriano/genética , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Egito , Filogenia , Salmonella/efeitos dos fármacos , Salmonella/genética , Salmonella/isolamento & purificação , Salmonella enterica/efeitos dos fármacos , Salmonella enterica/genética , Análise de Sequência de DNA , Sorogrupo , Combinação Trimetoprima e Sulfametoxazol/farmacologia
Vet World ; 10(10): 1281-1285, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29184377


Aim: This study describes the prevalence of Escherichia coli in frozen chicken meat intended for human consumption with emphasis on their virulence determinants through detection of the virulence genes and recognition of the extended-spectrum ß-lactamase (ESBL) encoding genes (blaOXA and blaTEM genes). Materials and Methods: A total of 120 frozen chicken meat samples were investigated for isolation of E. coli. All isolates were subjected to biochemical and serological tests. Eight serotypes isolated from samples were analyzed for the presence of various virulence genes (stx1, stx2, and eae A genes) using multiplex polymerase chain reaction (PCR) technique. Moreover, the strains were evaluated for the ESBL encoding genes (blaTEM and blaOXA). Results: Overall, 11.66% (14/120) chicken meat samples carried E. coli according to cultural and biochemical properties. The most predominant serotypes were O78 and O128: H2 (21.5%, each), followed by O121: H7 and O44: H18. Molecular method detected that 2 strains (25%) harbored stx1, 3 strains (37.5%) stx2, and 3 strains (37.5%) both stx1 and stx2, while 1 (12.5%) strain carried eae A gene. Particularly, only O26 serotype had all tested virulence genes (stx1, stx2, and eae A). The results revealed that all examined 8 serotypes were Shiga toxin-producing E. coli (STEC). The ESBL encoding genes (blaTEM and blaOXA) of STEC were detected in 4 (50%) isolates by multiplex PCR. The overall incidence of blaTEM and blaOXA genes was 3 (37.5%) and 2 (25%) isolates. Conclusion: The present study indicates the prevalence of virulent and ESBL-producing E. coli in frozen chicken meat intended for hospitalized human consumption due to poor hygienic measures and irregular use of antibiotics. Therefore, the basic instructions regarding good hygienic measures should be adapted to limit public health hazard.