Meng Qingling

Prevalence of Hydatid Cysts in Livestock Animals in Xinjiang, China

Hydatid worms, hosted by humans and animals, impose serious human health risk and cause significant livestock production loss. To better understand the disease infection status in Xinjiang, China, we investigated the disease epidemics in 4 livestock animals, i.e., cattle, sheep (both sheep and goat), camels, and horses, slaughtered at the abattoirs in Urumqi, Yining, Tacheng, and Altay areas. The results showed that the animals were infected at different rates, in the order of sheep (9.8%), cattle (8.4%), camels (6.8%), and horses (4.3%). The infection rates were found to be different between the abattoirs in various regions even for the same animals. For sheep, the rates increased significantly as the animals grew older. It was 1.9% before 1 year of age and increased to 8.2% in the age of 1-2 years, and further increased to 12.3% when the animals were 3-4 years old, and reached 17.2% when they were 5-6 year old. Sheep older than 6 years had an infection rate of 19.5%. This study demonstrates that the 4 livestock animals in the pastoral areas in Xinjiang were infected by the parasites to various extend. This study is the first systematic investigation of the hydatid worms in various livestock animals in Xinjiang, China, which provides epidemiological information about the infection of hydatid worms in livestock, and is valuable in developing strategies for prevention and control of the hydatid disease.

The recombinant serine protease XAoz1 of Arthrobotrys oligospora exhibits potent nematicidal activity against Caenorhabditis elegans and Haemonchus contortus

The nematophagous fungus Arthrobotrys oligospora is a potential biological agent against parasitic gastrointestinal nematodes. Its subtilisin-like serine proteases play an important role in nematode cuticle breach. In this study, the cDNA of the mature serine protease XAoz1 from A. oligospora XJ-XAo1 was expressed in Pichia pastoris to assess the in vitro nematicidal activity of recombinant XAoz1 (reXAoz1) on Caenorhabditis elegans and Haemonchus contortus. The cDNA sequence of the protease XAoz1 was amplified by reverse transcription polymerase chain reaction (RT-PCR) and inserted into the vector pPIC9K for expression in P.pastoris GS115. Our results show that the reXAoz1 had a molecular mass of 50 kDa after 3 days of 1.5%-methanol induction at 28 °C. The highest specific protease activity was achieved at 12 168 U mg(-1) protein. The reXAoz1 had the highest hydrolytic activity at pH 6.5-9.5 with an optimal pH at 8.5. Moreover, the purified reXAoz1 displayed a highly toxic and biological activity to immobilize C. elegans and H. contortus by degrading their cuticles and inducing death.

Antimicrobial resistance, virulence gene profiles and molecular typing of Staphylococcus aureus isolates from dairy cows in Xinjiang, Northwest of China

OBJECTIVES Staphylococcus aureus (SA) is a major pathogen causing dairy cow mastitis and endometritis. Recently, animal-derived SA strains pose a serious public-health threat. However, little is known about antimicrobial resistance and virulence factors of SA isolated from dairy cows in Xinjiang, China. In this study, antimicrobial resistance, virulence gene profiles and genotypes of SA from clinical mastitis and endometritis in dairy cows were investigated. METHODS A total of 337 clinical samples (186 milk samples from clinical mastitis cases and 151 endometritis swab samples) were collected from 15 large-scale dairy farms and were screened for SA. All SA isolates were subjected to antimicrobial susceptibility testing, detection of virulence genes and molecular typing. RESULTS A total of 155 SA strains were isolated; 22 (14.2%) were methicillin-resistant S. aureus (MRSA). Resistance of MRSA isolates was significantly higher than that of methicillin-susceptible S. aureus (MSSA). The percentage of virulence genes varied between MSSA and MRSA. The strains could be divided into two SCCmec types (I and IVa), three agr types (I, II and III) and four spa types (t779, t2883, t13751 and t1939). MLST identified 14 sequence types, among which ST1 and ST9 had relatively high detection rates. CONCLUSIONS These findings revealed that ST9-t1939-agrI was the main genotype of MSSA, whilst ST1-SCCmecI-t1939-agrI was the main genotype of MRSA from dairy cows. More significantly, a novel ST (STX) was identified for the first time. The majority of SA strains from dairy cows were multidrug-resistant and carried multiple virulence genes, posing a potential public-health risk.