Antimicrobial resistance and genomic characterization of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces of China in 2020 / 中华预防医学杂志

Objective: To understand the antimicrobial resistance and genome characteristics of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces in China in 2020. Methods: In 2020, 265 Campylobacter strains including 244 Campylobacter jejuni and 21 Campylobacter coli collected from retailed poultry meat samples in China were tested for antimicrobial resistance to 9 antimicrobial compounds by using the agar dilution method. Forty-two selected isolates were sent for whole genome sequencing and 38 high-quality genomes were analyzed for their antimicrobial resistance genes, virulence genes, sequence types and genetic diversity. Results: The resistance rates of Campylobacter isolates from poultry meats to tetracycline, nalidixic acid and ciprofloxacin were the highest (84%-100%), with 53.2% of the isolates showing multidrug resistance in this study. The resistance rates of C. coli to erythromycin, azithromycin, telithromycin, gentamicin and clindamycin were significantly higher than those of C. jejuni (P<0.05). The resistance genes conferring resistance to β-lactams (100%, 38/38), quinolones (94.7%, 36/38), tetracycline (81.6%, 31/38) and aminoglycosides (50%, 19/38) were the most frequently detected among 38 Campylobacter genomes. C. jejuni carried more virulence genes than C. coli. In total, 19 and 17 sequence types (ST) were obtained from 20 sequenced C. jejuni and 18 C. coli isolates, respectively, including 5 novel STs. The isolates showed a high genetic diversity based on their sequence types. Conclusion: The phenomenon of antimicrobial resistance in Campylobacter from poultry meat sources in China is relatively serious, and resistance and virulence genes are widely distributed in Campylobacter. There is genetic diversity in Campylobacter.

Antimicrobial resistance and genomic characterization of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces of China in 2020 / 中华预防医学杂志

Objective: To understand the antimicrobial resistance and genome characteristics of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces in China in 2020. Methods: In 2020, 265 Campylobacter strains including 244 Campylobacter jejuni and 21 Campylobacter coli collected from retailed poultry meat samples in China were tested for antimicrobial resistance to 9 antimicrobial compounds by using the agar dilution method. Forty-two selected isolates were sent for whole genome sequencing and 38 high-quality genomes were analyzed for their antimicrobial resistance genes, virulence genes, sequence types and genetic diversity. Results: The resistance rates of Campylobacter isolates from poultry meats to tetracycline, nalidixic acid and ciprofloxacin were the highest (84%-100%), with 53.2% of the isolates showing multidrug resistance in this study. The resistance rates of C. coli to erythromycin, azithromycin, telithromycin, gentamicin and clindamycin were significantly higher than those of C. jejuni (P<0.05). The resistance genes conferring resistance to β-lactams (100%, 38/38), quinolones (94.7%, 36/38), tetracycline (81.6%, 31/38) and aminoglycosides (50%, 19/38) were the most frequently detected among 38 Campylobacter genomes. C. jejuni carried more virulence genes than C. coli. In total, 19 and 17 sequence types (ST) were obtained from 20 sequenced C. jejuni and 18 C. coli isolates, respectively, including 5 novel STs. The isolates showed a high genetic diversity based on their sequence types. Conclusion: The phenomenon of antimicrobial resistance in Campylobacter from poultry meat sources in China is relatively serious, and resistance and virulence genes are widely distributed in Campylobacter. There is genetic diversity in Campylobacter.

Study of mtDNA 12S rRNA A1555G, GJB2, GJB3 gene mutation in Uighur and Han people with hereditary nonsyndromic hearing loss in Xinjiang / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To study mtDNA, GJB2, GJB3 and determine gene mutation situs and frequency in Uighur and Han people with hereditary nonsyndromic hearing loss, and to compare the differences of gene mutation situs and frequency between Uighur and Han people.</p><p><b>METHODS</b>Blood samples were obtained from 93 patients (43 Uygur and 50 Han) with hereditary non-syndromic hearing loss and 110 normal people (56 Uygur and 54 Han). Genomic DNA was extracted from isolated leukocytes, and amplified by polymerase chain reaction (PCR). PCR products of GJB3 were sequenced directly; while PCR products of mitochondrial DNA 12S rRNA A1555G point mutations were analyzed by PCR-Alw26I digestion, and positive ones were further sequenced. GJB2 genes of 83 patients (43 Uygur and 40 Han) with hereditary non-syndromic hearing loss and 98 normal people (46 Uygur and 52 Han) were directly sequenced.</p><p><b>RESULTS</b>Among GJB3 genes of 93 patients, 2 cases of 33C-T, 2 cases of of 766G-A, 7 cases of 357C-T, and 4 cases of 798C-T were detected. Mitochondrial DNA 12SrRNA A1555G mutation was detected in 8 patients (2 Uygur and 6 Han). Nine kinds of base changes of GJB2 were detected: 109G-A, 233-235delC, 79G-A, 196G-A, 341A-G, 564G-A, 380G-A, 71G-A, and 35delG. In the control group, detected GJB3 mutations included 4 cases of 357C-T, 5 cases of 798C-T, and 2 cases of 93C-T; while 9 kinds of base changes of GJB2 were detected: 341A-G, 380G-A, 457G-A, 79-GA, 109G-A, 281A-G, 21G-T, 171G-T, and 368C-A. For mtDNA 12SrRNA A1555G, the difference between study group of and control group of Han people was statistically significant (P < 0.05). For GJB2 mutation 79G-A, the difference between study group and control group was statistically significant (P < 0.05) in both Uygur and Han people; while for GJB2 mutation 341A-G, the difference in study group between Uygur and Han people was statistically significant (P < 0.05). And for GJB3 mutation 798C-T, the difference was statistically significant both between study group and control group, and between Uygur and Han people (P < 0.05).</p><p><b>CONCLUSIONS</b>In Xinjiang, mutation rate was high for mtDNA 12SRNA A1555G. while GJB3 gene mutations were not the main cause of the hereditary nonsyndromic hearing loss. There were certain ethnic and geographical characteristics of GJB2and GJB3 mutations.</p>