Analysis of proficiency testing results for pathogenic bacteria in laboratory animal in six years / 中国比较医学杂志

Objective To analyze the result of proficiency testing(PT)of detection activities for Laboratory animal pathogenic bacteria in 2011 and 2013-2017. To further improve the detection capacity of laboratory animal testing agency,and promote PT to be carried out in future. Methods During the six years(2011 and 2013 -2017), the National Institutes for Food and Drug Control conducted a total of six(seven projects)PT activities of laboratory animal pathogen bacteria. We analyzed the overall trend and the exposed problems by summarizing the result data of the PT in 6 years. Results A total of 45 laboratories in the country including 20 provinces and cities participated in the PT. The PT projects included Mycoplasma pulmonis, Clostridium piliformis, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella spp.,Klebsiella pneumoniae and Bordetella bronchiseptica. The satisfaction rates were 75%,87.5%,80.0%, 78.6%,93.3,96.2% and 88.0%, respectively. The main reasons of unsatisfactory results were for lack of incubation time,select errors of suspicious bacteria, biochemical identification errors, report writing errors and not timely feedback results. Conclusions The level of domestic laboratory animal pathogenic bacteria detection is gradually increased to achieve the desired goal through continuous proficiency testing activities.

Establishment and application of CODEHOP PCR assay for detection of Pasteurella spp.in laboratory animals / 中国比较医学杂志

Objective We established a rapid detection method of Pasteurella spp.and provided a reference for microbiological quality control of laboratory animal .Methods According to the β subunit of bacterial RNA polymerase ( rpoB) protein multiple alignments of 13 different Pasteurella spp.published in NCBI .The degenerate primers were designed by CODEHOP designer online .CODEHOP PCR method was applied to detecting Pasteurella spp.after the specificity and sensitivity of the method had been evaluated by 21 reference strains .Results Standard strain amplified fragment were about 200 bp by degenerate primers PastF6/PastR5.The primers are able to distinguish between Pasteurella spp.and the other pathognic organisms of laboratory animal respiratory tracts .Sensitivity of this method were 0.2 pg/μL~2 pg/μL to different Pasteurella.The Pasteurella positive rate was 19.1% in 609 animal ' s respiratory samples .The accuracy of positive results was 100%through verifying by sequenced and blast .Conclusions The established method has good specificity and sensitivity .It can be used to detect Pasteurella spp.in animal samples .

Establishment of a detection method for Helicobacter pylori in living Mongolian gerbil / 中国比较医学杂志

Objective To establish a detection technique for H.pylori(HP) infection in Mongolian gerbils using nested PCR technique.Methods H.pylori was cultured in vitro and inoculated into Mongolian gerbils.At the 10th week after infection, the HP in the gastric juice of Mongolian gerbil was detected by conventional PCR assay and the gastric juice, gastric mucosa, duodenal contents and colon stool were examined by nested PCR.Rapid urease test and ELISA were used to analyze the accuracy of the nested PCR assay.All of the PCR products were verified by sequencing.Results The positive rate of gastric juice detected by conventional PCR was 30%, while the positive rates of gastric juice, gastric mucosa, duodenal contents and colon stool detected by nested PCR were 100%, 100%, 90%, and 10%, respectively.The positive detection rates of rapid urease test and serum ELISA were 100% and 0%, respectively.Comparing the results of different methods, both the positive rates of gastric juice and gastric mucosa detected by nested PCR and the detection rate of rapid urease test were 100%, but the results of conventional PCR detection of gastric juice, the nested PCR detection result of stool in colon and of serum ELISA assay were lower than other methods.Conclusions Due to its high accuracy and sensitivity, the nested PCR assay of gastric juice can be used for the long-time detection of H.pylori infection in Mongolian gerbils, especially useful in the experiments of prevention and treatment of H.pylori infection.

Establishment of a multiplex real-time PCR method for quantitative detection of Campylobacter jejuni, Salmonella and Shigella in tree shrews / 中国比较医学杂志

Objective To establish a rapid, simple, sensitive, and specific multiplex real-time PCR method for quantitative detection of Campylobacter jejuni, Salmonella and Shigella in tree shrews.Methods Specific primers and probes were designed, according to the HipO gene of Campylobacter jejuni, inV gene of Salmonella and ipaH gene of Shigella.The primers were confirmed by single pathogen quantitative PCR, and the sensitivity and specificity of the multiplex PCR were analyzed.Finall, the samples of experimental tree shrews were detected by this multiplex PCR method.Results The PCR element of TaqMan-MGB real-time PCR assay was able to quantitatively amplify the Campylobacter jejuni, Salmonella or Shigella.Appropriate standard amplification curves of Campylobacter jejuni, Salmonella and Shigella in the multiplex quantitative PCR were obtained.The sensitivity of this method was 1×103 ng/μL.There was no false positive detection from other bacterial strains.Conclusions This multiplex quantitative real-time PCR method has good application and development prospects in the detection of microorganisms in tree shrews.

Prevalence and molecular identification of Syphacia muris in laboratory animals in China / 中国比较医学杂志

Objective To acquire the prevalence and molecular identification data on Syphacia muris and provide reference for the revision of national standard. Methods 923 batches of 5199 SPF animals ( including one batch of 5 monkeys, 3 batches of 25 mini?pigs, 28 batches of 55 rabbits, 13 batches of 248 hamsters, 37 batches of 198 guinea pigs, 93 batches of 459 rats, 742 batches of 4179 mice, 5 batches of 25 chickens and one batch of 5 ducks) and 145 batches of 1389 clean animals ( including one batch of 3 rabbits, 4 batches of 31 hamsters, 16 batches of 157 guinea pigs, 32 batches of 268 rats and 92 batches of 930 mice ) came from 50 different manufactures in China. Direct microscopy real?time dynamic video recording techniques in combination with morphological identification method were applied to screen the Syphacia muris infestation. A multiple polymerase chain reaction ( multiple?PCR ) testing of the isolate based on amplification of the conserved portions of the Syphacia muris internal transcribed spacer (ITS), 28S ribosomal RNA (28S rRNA), NADH dehydrogenase subunits 1 (nad1) and cytochrome c oxidase subunit 1 (cox1) genes, and the molecular sequencing of the multiple?PCR amplicons was used to confirm the Syphacia muris infection. Results Syphacia muris eggs, larvae and adults were detected by using direct microscopy real?time dynamic video recording technique. Syphacia muris were detected based on the morphology and size of ovum, larvae, and female and male adult worms. Multiple?PCR and sequencing were performed to identify ITS, 28S rRNA, nad1 and cox1 genes of DNA extracted from the single egg, larva and adult parasite Syphacia muris. This approach allowed the specific identification with no amplicon being amplified from heterogeneous DNA samples, and sequencing confirmed the identity of the amplified sequences. Molecular characterization by multiple?PCR amplification and sequencing of the ITS, 28S rRNA, nad1 and cox1 genes demonstrated the presence of Syphacia muris. Multiple?PCR followed by sequencing confirmed 285 of 5199 SPF and 135 of 1389 clean animal samples classified as positive by using direct microscopy real?time dynamic video recording technique in the study as containing Syphacia muris?specific DNA. Comparison of the partial sequences of the ITS, 28S rRNA, nad1 and cox1 genes revealed 100% similarity amongst Syphacia muris from different animals. The prevalence of Syphacia muris infection in SPF and clean animals were 5?5% (285/5199) and 9?7% (135/1389), respectively. Conclusions Direct microscopy real?time dynamic video recording technique, multiple?PCR and sequencing can be used to rapidly detect and accurately identify Syphacia muris. The zoonotic nature of Syphacia muris can be regard as a public health alter, hence the good quality control of animal has an important role in protecting human health and safeguarding people safety. This is the first molecular identification and infection investigation of Syphacia muris in SPF and clean animals in China.

Population genetic quality analysis of 3 subbreeds of China Agricultural University miniature pigs in Beijing / 中国比较医学杂志

Objective To analyze and evaluate the population genetic quality of 3 subbreeds of China Agricultural University miniature pigs in Beijing.Method According to the local standard DB11/T828.3 -2011, 25 pairs of microsatellite primers were used in 3 subbreeds of China Agricultural University miniature pigs, and software Popgen32 was used to process the data.Results 24 microsatellite loci shared 130, 122 and 138 alleles in the China Agricultural University miniature pigs I, II, III, respectively. The average heterozygosity was 0.6759, 0.5967 and 0.6779, respectively, while the average polymorphism information content ( PIC) was 0.6344, 0.5540 and 0.6403, respectively. The genetic distance between China Agricultural University miniature pig II and III was 0.4251, while the genetic distance between China Agricultural University miniature pig I and II was 0.2084.Conclusions In the 3 subbreeds, China Agricultural University miniature pigs II and III have genetic stability and genetic diversity, and both of which satisfy with the genetic characteristics of closed colony laboratory animal.

Results and analysis of the proficiency of laboratories in detection of Salmonella in laboratory animals / 中国实验动物学报

Objective To understand the Salmonella detectability in the laboratory animal testing laboratories, im-prove the level of detection for the quality of laboratory animals, by means of laboratory animals Salmonella proficiency tes-ting program.Method According to the proficiency testing program approved by CNAS, freeze-dried animal stool samples containing Salmonella bacteria and interference bacteria were prepared, and through stability and homogeneity tests quali-fied as proficiency testing samples.The randomly numbered samples were issued to the participating units by cold-chain transportation, and attached work instructions.The original reports and copies of the tests should be submitted on time.The sample results consistent with the results of the pretested results were considered as satisfactory, and the results inconsistent or fails to submit were judged as unsatisfactory.Results A total of 30 laboratories from 20 provinces and cities nationwide participated in this proficiency testing programs for Salmonella, including 28 ( 93.3%) laboratories with satisfactory re-sults, and two laboratories unsatisfactory ( 6.7%) .29 laboratories used separate culture methods, and two laboratories used PCR method.Conclusions The laboratory animal quality inspection agencies have good detection ability for Salmo-nella.The implementation of the capacity verification plan can well reflect the detection level of laboratories.

Evaluation of the detection proficiency of laboratories testing of mammalian orthoreovirus 3 antibody in laboratory mice / 中国实验动物学报

Objective Through the proficiency validation of testing of mammalian orthoreovirus 3 (Reo3)antibody in laboratory mice, to investigate the capacity of experimental animal quality control laboratories, so as to improve the de-tection capacity.Methods According to the program approved by CNAS, serum samples after calibration were tested for stability and homogeneity, and numbered randomly.The random samples were issued to the participant laboratories with the Standard Operation Procedure( SOP) .The participants must submit the test reports and original records in time.The feed-back results were judged by the concordance rate with the anticipated results.Results 27 laboratories from 17 provinces were enrolled in this evaluation project, all of them submitted detection results on time.Results All the 27 laboratories were marked as pass or excellent, with a pass rate of 100%.ELISA was used in 26 laboratories, and immunofluorescence assay was used in one laboratory.Conclusions The ability for detection of Reo3 antibody in laboratory mice in animal test laboratories is high.The implementation of proficiency testing can reflect the inspection level of quality control laborato-ries.

Evaluation of the ability to detect Staphylococcus aureus in experimental animal laboratories / 中国实验动物学报

Objective To verify the detection ability of experimental animal quality detection laboratories in China for Staphylococcus aureus.Methods The testing samples for Staphylococcus aureus detection were prepared by bacterial culture, homogeneity test and stability test, according to the study plan approved by CNAS.Then the samples and operation instruction were sent to the participant laboratories.The detection reports from these laboratories should be submitted before the deadline expires, and the collected data were summarized and analyzed.Results There were 28 laboratories which joined to this test plan.Among them 22 laboratories ( 78.57%) achieved satisfactory test results, and six laboratories (21.43%) had unsatisfactory test results.27 Laboratories used the national standard detection assay, while only one labo-ratory used PCR assay.Conclusions Most of experimental animal quality testing laboratories in China have sufficient pro-ficiency in detection of Staphylococcus aureus.The obtained information are very helpful for the laboratory ability verification testing in future.

Spindle cell carcinoma of the breast:a clinicopathologic analysis of three cases / 临床与实验病理学杂志

Purpose To analyze the clinical pathological characteristics and pathological diagnosis and prognosis of spindle cell carci-noma of the breast. Methods Three cases of spindle cell carcinoma of the breast were studied by morphological and immunohisto-chemical EnVision techniques. Results The females were 48, 63 and 71 years old. The tumors located in the right breast with 4. 0 cm × 3. 0 cm × 3. 0 cm, 3. 0 cm × 2. 0 cm × 2. 0 cm and 3. 5 cm × 2. 8 cm × 2. 3 cm in size and showed cystic lesion. The neoplasm was composed of bland spindle cells and mimicking fibromatosis. Immunohistochemical staining showed that spindle cells were positive for CK(AE1/AE3), CK(34βE12), CK14, CK5/6, p63 and vimentin, negative for ER, PR and c-erbB-2. Ki-67 was positive in 20%, 25% and 20% of the cells. Conclusion Spindle cell carcinoma of the breast is a rare subtype of the metaplastic carcinoma which tend to show cystic changes. It is important to make a definite diagnosis which combine histopathologic features and immunophe-notyping.

Development and application of a multiplex PCR assay for pathogenic dermatophytes in laboratory animals / 中国比较医学杂志

Objective To develop a multiplex polymerase chain reaction ( mPCR) assay for detection of four pathogenic dermatophytes [Trichophyton mentagrophytes (Tm), Microsporum gypseum (Mg), Microsporum canis (Mc), and Arthroderma simii ( As) ] in laboratory animals, which could be used rapidly and simultaneously for direct detection of those four pathogens.Methods We designed 5 specific primers according to 18S-28S rRNA sequences of the four pathogenic dermatophytes reported in Genbank. The four mPCR assays were established through optimizing the concentration of primers, dNTP, TaqDNA polymerase and the annealing temperature.After verifying the specificity and sensibility, this method was used to detect 15 hair samples with artificial infection and 260 samples taken from laboratory animals.Results This mPCR technique can distinguish the four dermatophytes by producing 192 bp( Tm) ,460 bp( Mg) , 290 bp( Mc) and 602 bp( As) fragments.The sensibility for detection of the four dermatophytes was 5.9 pg/μL, 6.6 pg/μL, 9.5 pg/μL and 5.1 pg/μL, respectively.The results of 15 artificial infection samples were accurate, and the results of 260 hairs samples were negative for the four fungi.Conclusions Our results suggest that the mPCR assay developed in this study can efficiently detect the four dermatophytes, is a useful and rapid technique for rapid detection of the pathogenic dermatophytes in laboratory animals.

Establishment and application of a Taqman MGB real-time PCR for the detection of Streptobacillus moniliformis / 中国比较医学杂志

Objective To establish a real-time quantitative PCR ( qPCR) method for detection of Streptobacillus moniliformis, which can be used to rapidly detect this pathogen in laboratory animals .Method According to the S. moniliformis sequences published in NCBI , we designed specific primers and MGB probe .The specificity, sensitivity and stability of this method were evaluated using 24 standard reference strains .Total of 823 respiratory specimens of animals including mice, rats, guinea pigs, hamsters, rabbits, Mongolian gerbils and tree shrews , were detected by this established Taqman MGB qPCR method .Results We had successfully established the S.moniliformis Taqman MGB qPCR method . S.moniliformis was not detected in the samples of mice , rats, guinea pigs, hamsters and rabbits.The positive rate of S. moniliformis was 1.5% ( 1/65 ) and 61.7% ( 37/60 ) in conventional Mongolian Gerbils and tree shrews , respectively . Conclusions Our developed qPCR method can be used to effectively detect S.moniliformis in laboratory animals .Moreover , its accuracy and sensitivity are better than the national standard method .This study laid the foundations for optimizing the quality inspection system of laboratory animals .

Establishment and application of a PCR method for detection of Bartonella in tree shrew / 中国比较医学杂志

Objective To establish an effective PCR assay for detection of Bartonella, and application of this assay in tree shrew .Methods Sequence of Bartonella was obtained from NCBI Genbank .Three pairs of primers were designed based on this sequence .One pair of primers was determined through amplifying the major strains in China .Sixty tree shrew blood samples were tested with this PCR assay .The positive amplified fragments were sequenced to verify the reliability of this method .Results A PCR method for detection of Bartonella is successfully established , with a high specificity and the sensitivity was of 2.0 ×10 -5 μg/mL.Among the tested 60 blood samples , 15 positive cases were detected.Sequencing of the samples confirmed a 25%infection rate of Bartonella in the tree shrews, well consistent with the amplification results , and verified the applicability of this detection method .Conclusion The establishment of this method provides the basis for detection of Bartonella in tree shrew.

Phenotypic analysis of Pasteurella pneumotropica in laboratory animals in Beijing area / 中国比较医学杂志

Objective To improve the accuracy of detection through analyzing the phenotypes of P.pneumotropica isolates in laboratory animals in Beijing area .Methods 306 suspicious P.pneumotropica strains were identified by biochemical identification and 16S rDNA sequencing.Then, to obtain the phylogenetic relationships combined with colony characteristics on blood agar plates and biochemical characteristics of 53 biotypes .Results BD Phoenix 100 automated bacterial identification system and 16S rDNA sequencing identified P.pneumotropica positive rate of 306 isolates were 164/306 and 227/306, respectively.There were 140 phenotypes in 227 true-positive strains, of which 106 were biotype Heyl and 23 were biotype Jawetz .Conclusions In the samples of laboratory animals in Beijing area , P.pneumotropica infection mainly are of biotype Heyl , and less is of biotype Jawetz .The phenotypes are diverse and widely distributed .

Investigation of Leptospira infection in three new experimental animals by PCR methods / 中国比较医学杂志

Objective To establish an effective PCR assay for leptospirosis detection , and applicate the assay in tree shrew, mongolian gerbil and gray hamster .Methods Sequence of leptospira was obtained from the NCBI Genbank , and primers were designed based on the sequences .The positive amplified fragments were sequenced to verify the reliability of the method.The samples from tree shrew, mongolian gerbils and hamsters were tested using this PCR method .Results The PCR method for detection of leptospirosis was successfully established .The positive rate of Leptospira was 8.33% in 60 samples of conventional tree shrews , 100% in 104 samples of the conventional Mongolian gerbils , and 0% in 60 samples of clean gray hamsters.Conclusions The establishment of this PCR assay is useful in the detection of leptospirosis in tree shrew, mongolian gerbil and gray hamster .The results of our investigation of leptospira infection levels of the three new experimental animals may promote their application in biomedical research .

Research progress on Pasteurella pneumotropica / 中国实验动物学报

Pasteurella pneumotropica is an opportunistic and zoonotic pathogen .It mainly infects rodents , especial-ly immunodeficient or immunosuppressied animals , and causes inflammation and abscesses .It is one of the highest positive rate infection pathogens in laboratory animals .The contamination and asymptomatic infections of Infection of P.pneumo-tropica could significantly interfere in vary experiments .This review will deal with P.pneumotropica epidemiology, detection and identification methods , molecular typing and control and so on .

Develonment and application of TaqMan MGB probe real-time fluorescence quantitative PCR for rapid detection of Helicobacter hepaticus / 中华微生物学和免疫学杂志

Objective To develop a TaqMan MGB probe-based,sensitive and specific real-time fluorescence quantitative PCR assay for rapid detection of Helicobacter hepaticus.Methods Primers and probes specific toflaB gene of Helicobacter hepaticus were designed.A TaqMan MGB probe-based,real-time fluorescence quantitative PCR was established.The specificity,sensitivity and stability of the assay were assassed.Then,the established TaqMan MGB probe real-time fluorescence quantitative PCR assay was applied to detect Helicobacter hepaticus in 1081 clinical specimens during 2008-2011,compared with bacterial isolation and culture method and conventional PCR assay.Results The specificity of this established TaqMan MGB probe-based real-time fluorescence quantitative PCR was high and there were no cross-reactivity with Helicobacter pylori,Campylobacter jejuni,Clostridium piliforme,Pasteurella pneumotropica,Escherichia coli,Pseudomonas aeruginosa.The detection limits was 8.3 copies.The correlation coefficient and slope value of standard curve were 0.999 and -3.227,respectively and the efficiency of TaqMan MGB-based probe realtime fluorescence quantitative PCR assay was 100％.The TaqMan MGB-based probe real-time fluorescence quantitative PCR and conventional PCR were preformed to detect Helicobacter hepaticus in 1081 clinical specimens,a total of 86 specimens were positive for Helicobacter hepaticus.However,there was only 4 specimens were positive by bacteria isolation and culture method.The results showed that TaqMan MGB -based probe real-time fluorescence quantitative PCR for Helicobacter hepaticas was more sensitive than bacteria isolation and culture method,and it could detect Helicobacter hepaticus DNA from clinical specimens directly,and detection time is only 2 hours.Conclusion The TaqMan MGB-based probe real-time fluorescence quantitative PCR assay was a reliable,specific,sensitive and useful tool for rapid detection of Helicobacter hepaticus.

High methylation of Ptchl gene involved in hedgehog signal pathway in human gastric carcinoma / 中华消化杂志

Objective To investigate the expression and aberrant methylation of Ptchl gene in hedgehog signal pathway in carcinogenesis of human gastric cancer.Methods The total RNA and genomic DNA were extracted from 10 human gastric carcinoma tissues,adjacent tissues(＞3 cm from cancerous tissue)and gastric cancer eell line AGS.Ptchl mRNA expression was detected by real-time quantitative reverse transcription PCR.The pattern of CpG island in Ptchl gene 5'regulation sequence was analyzed by software and its methylation extent was tested by bisulfite sequencing PCR.Results The analysis of CpG island(starting-3950 bases upstream of the Ptchl mRNAla transcription start site and ending 2050 bases downstream)revealed that there were two CpG islands in Ptchl gene 5' regulation sequence(first CpG:-1139 bp～+860 bp;second CpG:+875 bp～+1692 bp).Bisulfite sequencing PCR analysis of 19 CpG sites included in the first CpG island(-870 bp～+229 bp)showed that there was methylation present in all cell lines and the average extent of the methylation of these CpG sites was significantly higher in cancerous tissues(64%±32%,ranged 16%～100%)than that in adjacent tissues(13%±14%,ranged 0%～42%,P＜0.05).There was a negative correlation of the Ptchl methylation with its expression.Conclusion The high methylation of Ptchl gene that involves in the carcinogenesis of human gastric carcer will be a new biomarker for gastric carcer.