Prevalence and antimicrobial resistance profiles of Salmonella serotypes isolated from 7 chicken meat brands produced by different integrated broiler operations in Korea were determined. In total, 210 samples were collected from retail supermarkets in Seoul, South Korea, and analyzed for the presence of Salmonella. Of 210 chicken meat samples, overall Salmonella prevalence was 22.4%. Salmonella Enteritidis was the dominant serovar, with an isolation rate of 57.4% from the Salmonella-positive chickens, followed by Salmonella Montevideo. Salmonella isolates frequently were resistant to various antibiotics, including 100% to erythromycin, 87% to cephalothin, 85% to nalidixic acid, and 70% to streptomycin. Of the 47 isolates, 41 (87.2%) isolates were resistant to 3 or more antibiotics. Moreover, the Salmonella profiles of each chicken meat brand were different by broiler operation. Brand A showed the highest prevalence of Salmonella (18 isolates, 60%), whereas brand G showed the lowest prevalence (one isolate, 3.3%). Eight among the 18 isolates of brand A were resistant to 11 antibiotics, whereas 5 of the 6 brand C isolates were resistant to only 2 antibiotics. This study demonstrates that a high proportion of chicken meat in Korea is contaminated with Salmonella and the prevalence and antimicrobial resistance patterns of Salmonella of chicken meat differ significantly according to the integrated broiler operation.

Avian metapneumovirus (aMPV) causes upper respiratory tract infections in chickens and turkeys. Although the swollen head syndrome (SHS) associated with aMPV in chickens has been reported in Korea since 1992, this is the study isolating aMPV from chickens in this country. We examined 780 oropharyngeal swab or nasal turbinate samples collected from 130 chicken flocks to investigate the prevalence of aMPV and to isolate aMPV from chickens from 2004-2008. Twelve aMPV subtype A and 13 subtype B strains were detected from clinical samples by the aMPV subtype A and B multiplex real-time reverse transcription polymerase chain reaction (RRT-PCR). Partial sequence analysis of the G glycoprotein gene confirmed that the detected aMPVs belonged to subtypes A and B. Two aMPVs subtype A out of the 25 detected aMPVs were isolated by Vero cell passage. In animal experiments with an aMPV isolate, viral RNA was detected in nasal discharge, although no clinical signs of SHS were observed in chickens. In contrast to chickens, turkeys showed severe nasal discharge and a relatively higher titer of viral excretion than chickens. Here, we reveal the co-circulation of aMPV subtypes A and B, and isolate aMPVs from chicken flocks in Korea.

Mycoplasma synoviae (MS) is a common respiratory pathogen in the poultry industry. Eradication of MS from broiler breeder flocks is important for reducing economic losses caused by MS-associated diseases on broiler farms. An outbreak of MS infection was detected on a multi-age Korean broiler breeder farm that implements a flock replacement program every 3 to 6 months and uses A-type cages. Continuous administration of tilmicosin after 2 rounds of intensive antibiotics treatment with chlortetracycline, doxycycline, and enrofloxacin reduced MS shedding from the MS-positive flocks and eventually eradicated MS from the farm. Flock 3 was the last MS-positive flock by both PCR and enzyme-linked immunosorbent assay (ELISA), while flocks introduced to the farm after flock 3 were MS-negative by both PCR and ELISA at the time of depletion. This is the first report of successful eradication of MS from a multi-age broiler breeder farm using continuous antibiotic treatments.

The purpose of this study was to investigate the distribution of Salmonella species in an integrated broiler supply chain in Korea. A total of 1,214 samples from various steps of an integrated broiler production company including broiler breeder farms, broiler farms, broiler trucks, slaughterhouse, and retail chicken meats were collected and investigated. Salmonella was detected in 195 of the samples. The highest prevalence of Salmonella was observed in broiler transporting trucks (71.43%), followed by the slaughterhouse (63.89%) and broiler farms (16.05%). Salmonella Hadar was the most frequently isolated serotype (83.08%). All Salmonella Hadar isolates investigated in this study with pulsed-field gel electrophoresis showed the same XbaI pulsed-field gel electrophoresis pulsotype.

Background General antiviral agents such as oseltamivir are associated with certain adverse effects and the emergence of resistance. This study investigated the phytochemical properties, antiviral activities, and safety of three herbs used in traditional Korean medicine. Methods Extracts of three medicinal herbs (Brassica juncea, Forsythia suspensa, and Inula britannica) were prepared using ethanol or water. The total phenolic, flavonoid, and saponin content, condensed tannin content, and reducing sugar content of the herb extracts were determined via phytochemical screening. Tandem mass analysis was performed using an ultra-performance liquid chromatography (UPLC)-electrospray ionization (ESI)-Q/Orbitrap instrument. Virus titrations were determined via tissue culture infective dose (TCID50) and cytotoxicity assays. Hemolysis and hepatotoxicity were measured to determine safety. Results Among the three medicinal herbs, F. suspensa showed the highest concentration of phenolic compounds, flavonoids, and saponins. The number of phytochemical compounds detected via tandem mass analysis of B. juncea, F. suspensa, and I. britannica was 5 (including sinigrin, m/z [M-H] = 358.02), 14 (including forsythoside A, m/z [M-H] = 623.19), and 18 (including chlorogenic acid, m/z [M-H] = 353.20), respectively. The antiviral effects of the B. juncea extracts (ethanol and water) and I. britannica extract (ethanol) were further investigated. The ethanol extract of B. juncea showed a 3 Log TCID50/25 μL virus titration reduction and the water extract showed a selectivity index of 13.668 against infected influenza H1N1 virus A/NWS/33. The B. juncea extracts did not show hemolysis activities and hepatotoxicity (< 20%). The ethanol extract of I. britannica showed the most effective virus titration decrease, whereas its hemolytic and hepatotoxicity values were the most significantly different compared to the control. Despite the high concentration of phytochemicals detected in F. suspensa, the extract showed approximately 1 Log TCID50/25 μL at the highest concentration. Conclusion B. juncea may show antiviral effects against H1N1 in a host. In addition, B. juncea may also show decreased disadvantages compared to other antiviral agents.