The Presence of Poultry Influenza Strains in Two Live Bird Markets near the East-West Boundary of Vietnam

The spread of avian influenza virus among Asian countries is becoming a concern after influenza epidemics in recent years. This study is aimed at identifying the subtypes of avian influenza viruses collected from healthy chickens and ducks at two live bird markets in a border province of Vietnam and the Lao People Democratic Republic. Cloacal and tracheal swab samples from 100 chickens and 101 ducks were collected in May 2017. All samples were screened to detect avian influenza virus by real-time reverse transcriptase PCR. Samples that are avian influenza virus-positive were isolated in embryonated chicken eggs, and the subtypes were identified by RT-PCR with the specific primers. The samples positive for influenza virus H5 were sequenced to identify HA and NA genes. The prevalence of avian influenza virus (AIV) among chicken and duck samples was 27.5% (55/200) and 24.8% (50/202), respectively. AIV subtypes identified among 17 samples positive with the hemagglutination test include H3N6, H6N6, and H9N2. Of these 17 samples, 7 duck samples were found to be H6N6, 4 duck samples were infected with both subtypes of H3N6 and H6N6, and two chicken samples were recorded as H9N2. A positive chicken sample with A/H5 contains 99% similarity nucleotide with H5N6 reference strain. Results suggested that while the presence of low pathogenic avian influenza virus is predominant, potential risks of the appearance of high pathogen avian influenza virus in the east-west boundary in Vietnam should be concerned and studied further. Furthermore, prevention activities are needed to reduce such biosecurity threats in Vietnam and other Asian countries.

Multilocus analysis of Gallid herpesvirus 1 in layer chickens in Iraq

Background and Aim: Infectious laryngotracheitis virus (ILTV) causes a highly pathogenic respiratory disease that affects poultry. It is also known as Gallid herpesvirus 1. ILT prophylaxis measures often include using live attenuated vaccines. The live attenuated vaccine can, however, lead to the formation of new strains of ILTV as a result of vaccine reversion and recombination with field strains. Therefore, this study was performed to explore the multilocus variation of ILTV strains of field and vaccine origin. Samples were tested from two distinctive geographical areas in Iraq as little is known about the ILTV genetic diversity within these areas. Materials and Methods: The polymerase chain reaction method was utilized to generate sequencing templates of six highly polymorphic genes, including UL54, UL52, gB, ICP18.5, ICP4, and gJ in the layer chicken sample (n=15). The Western blotting technique was also employed to detect and estimate the native molecular weight of gE. Results: The results revealed an important degree of genetic relatedness between the field and vaccine strains across all genes. In addition, gE was found to be expressed natively at 49 kDa. Conclusion: The findings of this study may be used to improve the production process of the vaccine for more effective ILT prophylaxis and could further the understanding of epidemiologists and immunologists to better control ILT in the future.

Prevalence, antimicrobial resistance and staphylococcal toxin gene of blaTEM-1a-producing Staphylococcus aureus isolated from animals in Chongqing, China

Background Livestock-associated Staphylococcus aureus is one of the most important etiological agents in both human and animals. It has been reported with high antimicrobial resistance and multiple staphylococcal superantigen genes in many countries and several provinces of China. However, large-scale investigation of this organism has not been documented in Chongqing, China. The aim of this study is to demonstrate the prevalence, antimicrobial susceptibility and some molecular characteristics of S. aureus acquired from animals in Chongqing. Results A total of 89 S. aureus isolates were cultured from 1371 samples picked up from March 2014 to December 2017. The isolates were originated from pigs (25), cattle (6), goats (10), rabbits (16) and chicken (32). Four MRSA strains were identified from 3 pig samples and 1 chicken sample. The isolates showed high resistance to penicillin (93.3%) and ampicillin (92.1%), but were more susceptible to amikacin and ofloxacin, since the resistance rates of these two drugs were less than 10%. Meanwhile, 74.2% isolates exhibited varying degree of MDR. Almost all strains, except for 3 chicken-originated isolates, were positive for blaTEM-1a, but did not harbor other ESBL genes. Nineteen staphylococcal SE/SEl/TSST-1 genes, except seq, were detected in isolates. The predominant genes were sei (58.4%), tst-1 (56.2%) and seg (51.7%). Conclusions The high antimicrobial resistance and prevalence of blaTEM-1a seriously reminded that it was urgent to standardize and cut down the usage of antimicrobials. The universal existence of staphylococcal toxin genes in isolated strains implied a potential threat of public health from animals to human through the food chain.

Determination of Six Macrolide Antibiotics in Chicken Sample by Liquid Chromatography-Tandem Mass Spectrometry Based on Solid Phase Extraction

In this paper, a simple and effective method for the determination of six macrolide antibiotics (MACs), including tylosin, tilmicosin, azithromycin, clarithromycin, roxithromycin, and kitasamycin, in the chicken sample using liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed based on a self-built porous aromatic framework- (PAF-) based solid phase sorbent. The main parameters influencing the extraction efficiency, such as sorbent amounts, type of the eluent, pH of the sample, and the eluent volume, were evaluated. Under the optimized condition, the limits of detection were from 0.2 to 0.5 μg·kg−1. The recoveries of the method ranged from 82.1% to 101.4% with the relative standard deviations less than 11.1%. All the results demonstrated that the established method is potential for the determination of macrolide antibiotics in food safety analysis and monitoring.

Prevalence and Antimicrobial Resistance of Salmonella Serovars in Conventional and Organic Chickens from Louisiana Retail Stores

In this 1-year survey from October 2006 to September 2007, we isolated and characterized 126 Salmonella isolates from conventionally raised (n = 141) and organically raised (n = 53) chicken carcasses obtained from 27 retail stores in Baton Rouge, Louisiana. Salmonella was isolated from 22% of conventional and from 20.8% of organic chicken samples. Eight Salmonella serovars were identified; predominant ones included Kentucky, Hadar, and Enteritidis. The vast majority of isolates within the same chicken sample possessed the same pulsed-field gel pattern. All Salmonella isolates were susceptible to amikacin, ceftriaxone, and ciprofloxacin; however, decreased susceptibility to quinolones (7.1%) or extended-spectrum cephalosporins (45.2%) was observed. Resistance to multiple antimicrobials (two or more) was found among 52.4% of the Salmonella isolates. Antimicrobial resistance profiles differed greatly among Salmonella serovars and also depended on the type of chicken from which they were recovered. Salmonella Kentucky isolates from organic chicken samples were susceptible to 11 of the antimicrobials tested, whereas those from conventional chickens were only susceptible to 4 antimicrobials. Three Salmonella Kentucky isolates from conventional chickens possessed multidrug resistance phenotype MDR-AmpC. Results of this study provide baseline data on both prevalence and antimicrobial resistance of Salmonella in retail chickens in this region and emphasize the need for implementing effective control measures to reduce Salmonella contamination and the levels of antimicrobial-resistant Salmonella in both conventionally and organically raised poultry products. Further studies involving larger sample sizes over time are needed to better monitor and assess the trend of prevalence and antimicrobial susceptibility among Salmonella serovars in retail chickens.

Isolation and Identification of Listeria monocytogenes from Retail Meats in Beijing

To determine the contamination of retail meats by Listeria monocytogenes in Beijing, 70 meat samples (25 pork, 10 beef, 14 lamb, and 21 chicken) were analyzed between January and March in 1990. Eight (11%) samples were positive for L. monocytogenes, and 39 (56%) samples were found to contain other Listeria spp. Seven pork and one chicken sample contained L. monocytogenes, whereas all beef and lamb were free of L. monocytogenes. Meanwhile, 15 (60%) pork, 11 (52%) chicken, 7 (70%) beef, and 6 (43%) lamb samples were positive for other Listeria spp. The eight confirmed isolates of L. monocytogenes were serologically typed. Six (5 from pork and 1 from chicken) were serotype l/2a, and the other two isolates (2 pork) were serotype l/2c and l/2b. No isolates were of serotypes 3 and 4. All positive samples for L. monocytogenes were frozen meats, and the incidence of Listeria spp. was greater for frozen samples than for fresh. Sixty of 70 samples (22 pork, 8 beef, 11 lamb, and 19 chicken) were used to compare the effectiveness of Oxford medium and Palcam medium for the isolation of L. monocytogenes from meat samples. L. monocytogenes was isolated from seven samples by Palcam medium, while five samples were positive by Oxford medium, indicating that Palcam medium was more effective for recovering L. monocytogenes than Oxford medium.