CHARACTERIZATION OF FOUR MAIN SALMONELLA SEROVARS, ALBANY, KENTUCKY, MBANDAKA, AND MONTEVIDEO, ASSOCIATED WITH CHICKEN LINES, FARMS, AND SAMPLE SOURCES IN SOUTHERN TAIWAN

Abstract

Poultry and its products are often referred to as reservoirs of Salmonella to infect humans. Salmonella serovars were determined from samples of terminated eggs (early-terminated eggs, EEs, and late-terminated eggs, LEs) on farms YA (layers), YB (native hybrid broilers, NHCs), and YF (NHCs); one-day-old chicks (OCs) on farm YB; and shoe covers (SCs) on farms YB, YC (broilers), YD (broilers), YE (NHCs), and YF using multiplex PCR and agglutination methods. One hundred isolates were examined for susceptibility to 13 antimicrobials and profiles of pulsotypes and plasmids. Nine serovars were identified as serogroup B Agona and Schwarzengrund, serogroup C1 Montevideo and Mbandaka, serogroup C2 Albany, Kentucky and Newport, serogroup E Weltevreden, and serogroup G Kedougou. Different from those in 2003, Albany, Kentucky, Montevideo, and Mbandaka were the predominant serovars that differed in chromosomal and plasmid variations and antibiogram profiles. Albany and Kentucky isolates had higher resistance levels to the antimicrobials than the Montevideo and Mbandaka isolates. The antibiogram differences among the serovars may be related to the presence of antibiotic resistance genes in Salmonella genomic island 1-F (SGI1-F) and plasmids in Albany isolates. Albany and Kentucky exhibited the largest chromosomal and plasmid variations, respectively. The main serovars associated with embryogenesis termination were Mbandaka and Montevideo in EEs and LEs, Newport in NHCs, and Kedougou in LEs from layers. Furthermore, Montevideo and Agona were the only serovars detected in OCs, and Albany and Kentucky were the main serovars on SCs. Farm management also affected the Salmonella prevalence and predominant serovars.