Interpretation for the group standards of the Isolation and Identification of Campylobacter jejuni and Campylobacter coli / 中华流行病学杂志

Foodborne Campylobacter is recognized as the leading causes of the bacterial diarrheal illness in both developing and developed countries. C. jejuni and C. coli caused 95% of the human campylobacterisosis. Bacteria culture has been recognized as the "Gold standard" for the diagnosis of the Campylobacter infection. The National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention coordinated the experienced researchers from China National Center for Food Safety Risk Assessment and other local Centers for Disease Control and Prevention to write up the standards for entitled Isolation and Identification of Campylobacter jejuni and Campylobacter coli (T/CPMA 006-2019). The standard is drafted with principles of emphasizing the scientific, normative, applicability and feasible nature. This group standard recommended the procedures and steps for the isolation and identification of C. jejuni and C.coli from variant samples. The standard aims to improve the capacity for Campylobacter identification in China.

Study on the Differences of Virulence Genes and Molecular Typing in Campylobacter Jejuni Isolates from Poultry Products and Diarrhea Patients in Shenzhen / 现代检验医学杂志

Objective To understand the differences of virulence genes and molecular typing in Campylobacterjejuni isolates from poultry products and diarrhea patients in Shenzhen.Methods According to specific primers,four virulence genes (cdtB,cadF,flaA,virB1 1 )of C.jejuni were detected by polymerase chain reaction (PCR).Molecular typing for C.jejuni strains was performed by Pulsed-field gel electrophoresis (PFGE).Results There were no differences of gene distribution (cdtB+,cadF+,virB1 1-)between isolates from poultry products and diarrhea patients.Two virulence genes of cdtB and cadF were found in all of ten C.jejuni strains lacking virB1 1 .The carriage rate of flaA in food-borne isolates (3/5 )was higher than those in patient isolates (2/5).In the PFGE map,the clustering analysis of C.jejuni strains showed that a total of 5 to 9 DNA bands were observed in ten strains through the digestion of Sam I.There was high homology (above 85%) between food-borne isolates and patients isolates,but the distribution of flaA in these highly homologous strains was differ-ent.Conclusion So far,C.jejuni strains with cdtB,cadF and flaA were present in Shenzhen,and showed high diversity and homology.This implies that the occurrence of diarrhea in patients with C.jejuni was associated with the contaminated poul-try products by this pathogen.Their findings can provide basic data and evidences about diarrheal disease caused by food-borne C.jejuni for the local region.

Genetic characterization of Vibrio parahaemolyticus O3: K6 serovariant isolated in Shenzhen / 中华预防医学杂志

<p><b>OBJECTIVE</b>To characterize the O3: K6 serovariant of Vibrio parahaemolyticus on virulence gene and molecular typing, and analyze the genetic relationship between O3: K6 and O3: K6 serovariants.</p><p><b>METHODS</b>PFGE was performed on 115 strains of V.parahaemolyticus which were collected from the anal swab of cases of foodbrone diseases in Shenzhen during 2006-2012. According to isolation times and locations, 7 strains of O3: K6 were selected as control strains. Tdh gene, trh gene, orf8 gene were detected, GS-PCR, multi-locus sequence typing (MLST) were used to chracterize 7 strains of O3: K6 and O3: K6 serovariants.</p><p><b>RESULTS</b>PFGE indicated that 58.3% (67/115) of V. parahaemolyticus strains shared a high similarity of band pattern (similarity > 80%) , which comprised of O3: K6 (44/67), O1: KUT(4/67), and O3: K6 serovariants(19/67). Among the O3: K6 serovariants, O1: K25 accounted for 7% (5/67), O4: K68 accounted for 10% (7 /67), O11: K36 accounted for 10% (7 /67). They all carried both tdh and trh gene, and 53% (10/19) was GS-PCR positive and carried orf8 gene, 26% (5/19) was both GS-PCR and orf8 gene negative, 21% (4/19) was GS-PCR negative, orf8 gene positive, 89% (17/19) was assigned to ST-3, 11% (2/19) was assigned to ST-305. Seven strains of O3: K6 was GS-PCR positive, carried orf8 gene, assigned to ST-3. ST-305 and ST-3 had differences in 2 housekeeping genes, which was dtdS gene and pntA gene. In the 305th base of dtdS gene, ST-305(147 allele profile) was T, while ST-3(4 allele profile) was C. In the 33th base of pntA gene, ST-305(93 allele profile) was T, while ST-3(29 allele profile ) was C.</p><p><b>CONCLUSION</b>O4: K68,O1: K25 and O11: K36 were highly similar in virulencec gene carriage, MLST type of O3: K6, and aslo shared a close genetic relationship with O3: K6, thus were considered as O3: K6 serovirants.</p>

Influence Factors Acted on Germicidal Efficacy of a Bed Unit Ozone Sterilizer / 中华医院感染学杂志

OBJECTIVE To study the influence factors acted on germicidal efficacy of a bed unit ozone sterilizer. METHODS All the experiments were carried out according to the Technical Standard for Disinfection. RESULTS After working for 20min,the concentration of ozone in disinfection packet attained to 765.21 mg/m~3,the killing rates of Staphylococcus aureus were 90.96%,95.46% or 99.35% under the relative humidity(RH) of 50%,70% or 90% at 20℃,the killing rates were 95.56%,68.36% or 66.42% at 20℃ and RH 70% in the presence of 0%,25% or 50% organic substances,the temperature and carriers had little influence on killing rate. CONCLUSIONS Considering the strong influences of relative humidity,and organic substance on ozone sterilizer,we should increase the concentration of ozone or improve the conditions of disinfection in actual use to assure the germicidal efficacy.