Microbiota Analysis of Eggshells in Different Areas and During Different Storage Time by Non-cultural Methods.

This study is to investigate and characterize the microbiota composition on eggshells from 3 different areas of Shaanxi province (Yulin, Hanzhong and Xi'an). The eggs were stored at 25 °C for 56 days and bacterial samples were collected from eggshells on day 0, 14, 28, 42 and 56. Denaturing gradient gel electrophoresis and high-throughput sequencing of 16S rRNA hypervariable region V3-V4 were performed. Alpha diversity was applied for analyzing the diversity of samples through 6 indices, including Observed-species, Chao1, Shannon, Simpson, ACE and Good's-coverage. Beta diversity was used to study the similarities or differences in the community composition of the samples. Totally, 36 phyla and 595 genera were classified by 16S rRNA gene sequencing. The composition of the microbial communities of different regions was quite different. Firmicutes (33-38% of total phyla) and Actinobacteria (36-61% of total phyla) were the most abundant phyla in all three regions. Proteobacteria were relatively more abundant (about 18% of total phyla) on eggs from Hanzhong. During storage time, the microbial communities mainly changed from Firmicutes to Actinobacteria on eggs from Yulin and Xi'an. Lactobacillus, Kocuria and Streptomyces were much higher at the genus level. Spoilage bacteria Staphylococcus, Streptococcus, Pseudomonas and Enterococcus were detected at the genus level. Campylobacter jejuni (< 1% of total bacteria), which might be related to human illness, was also detected. In conclusion, the structure, abundance, and composition of microbiota on eggshells differ among areas. The microbiota changed regularly during storage time. The current study may offer a new insight into bacterial species on eggshells.

[Antimicrobial resistance profiles and genetic diversity of bovine staphylococcus aureus isolated in 5 provinces of China in 2013].

OBJECTIVE: To investigate antimicrobial resistance profiles and genetic diversity of staphylococcus aureus isolated from lactating cows of 5 provinces in China, 2013. METHODS: A total of 680 samples were collected from 15 herds (12 farms, 3 artels) in 5 provinces of China in 2013, including swabs of extramammary sites (bovine teat skin and milking machine liners) and quarter milk samples from lactating cows diagnosed with subclinical mastitis. The antimicrobial resistance of the isolates were tested by broth microdilution method and the genotypes were determined by PFGE (pulsed-field gel electrophoresis) method. RESULTS: A total of 111 isolates were isolated and identified as staphylococcus aureus. Resistance to penicillin (90.1% (100/111)), erythromycin (48.6% (54/111)), ciprofloxacin (36.9% (41/111)), clindamycin (27.9% (31/111)), gentamycin (18.9% (21/111)), chloramphenicol (9.0% (10/111)), tetracycline (7.2% (8/111)) of these strains were observed. All isolates were sensitive to oxacillin, vancomycin and selectrin. 92.8% (103/111) staphylococcus aureus isolates were resistant to at least one antimicrobial. 38.7% (43/111) strains were multi-drug resistant isolates. The resistance rate of isolates in artels (100% (48/48)) was higher than it in farms (87% (55/63)) and the difference was statistically significant (χ(2) = 4.80, P < 0.05). The multi-resistance rate of isolates in artels (54% (26/48)) was higher than it in farms (27% (17/63)) and the difference was also statistically significant (χ(2) = 8.48, P < 0.05). The 111 strains were clustered into 8 types, 6 out of which were consisted of 98% isolates (109/111), and were prevalent in 2 to 9 herds. Every herd had 1 to 4 types, and tend to be comprised by one major type. Most swab isolates were indistinguishable from isolates infecting the mammary gland. There were no relationship between antimicrobial resistance profiles and genotypes of these isolates. CONCLUSION: The drug resistance of staphylococcus aureus isolates associated with lactating cows of 5 provinces in China is serious, especially the isolates collected from artels. A few specialized clones were responsible for most of the cases of bovine mastitis in a single herd and some clones might have a broad geographic distribution.

Genetic source tracking of an anthrax outbreak in Shaanxi province, China.

BACKGROUND: Anthrax is an acute zoonotic infectious disease caused by the bacterium known as Bacillus anthracis. From 26 July to 8 August 2015, an outbreak with 20 suspected cutaneous anthrax cases was reported in Ganquan County, Shaanxi province in China. The genetic source tracking analysis of the anthrax outbreak was performed by molecular epidemiological methods in this study. METHODS: Three molecular typing methods, namely canonical single nucleotide polymorphisms (canSNP), multiple-locus variable-number tandem repeat analysis (MLVA), and single nucleotide repeat (SNR) analysis, were used to investigate the possible source of transmission and identify the genetic relationship among the strains isolated from human cases and diseased animals during the outbreak. RESULTS: Five strains isolated from diseased mules were clustered together with patients' isolates using canSNP typing and MLVA. The causative B. anthracis lineages in this outbreak belonged to the A.Br.001/002 canSNP subgroup and the MLVA15-31 genotype (the 31 genotype in MLVA15 scheme). Because nine isolates from another four provinces in China were clustered together with outbreak-related strains by the canSNP (A.Br.001/002 subgroup) and MLVA15 method (MLVA15-31 genotype), still another SNR analysis (CL10, CL12, CL33, and CL35) was used to source track the outbreak, and the results suggesting that these patients in the anthrax outbreak were probably infected by the same pathogen clone. CONCLUSIONS: It was deduced that the anthrax outbreak occurred in Shaanxi province, China in 2015 was a local occurrence.