Genomic Epidemiology of Imported Cases of COVID-19 in Guangdong Province, China, October 2020 - May 2021 / 生物医学与环境科学（英文）

Objective@#The pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been engendering enormous hazards to the world. We obtained the complete genome sequences of SARS-CoV-2 from imported cases admitted to the Guangzhou Eighth People's Hospital, which was appointed by the Guangdong provincial government to treat coronavirus disease 2019 (COVID-19). The SARS-CoV-2 diversity was analyzed, and the mutation characteristics, time, and regional trend of variant emergence were evaluated.@*Methods@#In total, 177 throat swab samples were obtained from COVID-19 patients (from October 2020 to May 2021). High-throughput sequencing technology was used to detect the viral sequences of patients infected with SARS-CoV-2. Phylogenetic and molecular evolutionary analyses were used to evaluate the mutation characteristics and the time and regional trends of variants.@*Results@#We observed that the imported cases mainly occurred after January 2021, peaking in May 2021, with the highest proportion observed from cases originating from the United States. The main lineages were found in Europe, Africa, and North America, and B.1.1.7 and B.1.351 were the two major sublineages. Sublineage B.1.618 was the Asian lineage (Indian) found in this study, and B.1.1.228 was not included in the lineage list of the Pangolin web. A reasonably high homology was observed among all samples. The total frequency of mutations showed that the open reading frame 1a (ORF1a) protein had the highest mutation density at the nucleotide level, and the D614G mutation in the spike protein was the commonest at the amino acid level. Most importantly, we identified some amino acid mutations in positions S, ORF7b, and ORF9b, and they have neither been reported on the Global Initiative of Sharing All Influenza Data nor published in PubMed among all missense mutations.@*Conclusion@#These results suggested the diversity of lineages and sublineages and the high homology at the amino acid level among imported cases infected with SARS-CoV-2 in Guangdong Province, China.

Surveillance and analysis on the pathogenic features of Salmonella in Guangdong province in 2010 / 中华预防医学杂志

<p><b>OBJECTIVE</b>In order to better understand the nature of Salmonella infection in diarrheal patients in Guangdong province, the study analyzed the serum types, antibiotic resistance and molecular determinants of the isolated Salmonella strains.</p><p><b>METHODS</b>In year 2010, 8405 diarrhea patients from 16 surveillant hospital in Guangzhou, Zhongshan, Dongguan, Zhuhai, Maoming, Yangjiang and Jiangmen cities in Guangdong province, were recruited in the study. A total of 8405 fecal specimen were collected and subjected to Salmonella isolation and culture. The isolated Salmonella strains were further analyzed via serotyping, antimicrobial susceptibility testing, and PFGE. The χ(2) test was applied to compare the differences between the isolated Salmonella strains in different seasons and districts. BioNumerics software was used to analyze the PFGE results in order to determine the correlation between different Salmonella strains.</p><p><b>RESULTS</b>The positive rate of the surveillant Salmonella in Guangdong province was 3.58% (301/8405) in 2010; with the gender ratio at 1.34:1 (166/124). Salmonella infection was found in all age groups, and most in infants, accounting for 57.48% (173/301). The isolated rates of Salmonella were separately 3.48% (61/1751), 4.97% (134/2695), 3.08% (73/2370) and 2.08% (33/1589) in the four seasons; and the difference was statistically significant (χ(2) = 27.29, P < 0.01). The isolated rates of Salmonella in different regions were as follows: Zhuhai 15.43% (25/162), Maoming 7.53% (18/239), Dongguan 6.51% (39/599), Yangjiang 3.64% (14/385), Zhongshan 3.03% (70/2309), Guangzhou 2.90% (126/4349) and Jiangmen 2.49% (9/362). The difference between regions was statistically significant (χ(2) = 100.75, P < 0.01). Except one strain of the isolated Salmonella cannot be serotyped, the other 300 strains were divided into 42 serotypes, of which Salmonella typhimurium and Salmonella enteritidis were dominant, account for 45.18% (136/301) and 10.96% (33/301) respectively. Although over 85% of Salmonella were sensitive to cephalosporin, ACSSuT resistance patterns (defined as resistance to at least ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline) reached 34.88% (105/301), the highest resistant rate was found in serotype Salmonella typhimurium, as high as 65.44% (89/136). 136 strains of Salmonella typhimurium were divided into 51 PFGE types, showed great genetic diversity. 33 strains of Salmonella enteritidis were divided into 18 PFGE types. The strains with same PFGE pattern may have different drug-resistant patterns, and vice versa.</p><p><b>CONCLUSION</b>Salmonella typhimurium and Salmonella enteritidis were the dominant serotypes causing infectious diarrhea in Guangdong province. Cephalosporin was the primary choice in clinical medicine. However, Salmonella typhimurium was resistant to drug most seriously in Guangdong province. There was no significant correlation between Salmonella resistance patterns and PFGE type.</p>

Automated ribotyping of Salmonella and Staphylococcus aureus in food poisoning of Guangdong province / 中华流行病学杂志

Objective To understand the genetic polymorphism of Salmonella and Staphylococcus aureus in Guangdong province, as well as to explore methods for identifying and tracing the source of these two foodbome pathogens. Methods Using the automated ribotyping system, two foodbome pathogens were tested with either EcoR Ⅰ or Pvu Ⅱ restriction enzymes. BioNumerics software was then applied for image analysis, database establishment and other corresponding analysis. Results Digestion of 32 Salmonella isolates with Pvu Ⅱ yielded 19 different ribotypes,and digestion of 14 Salmonella isolates with EcoR Ⅰ yielded 2 different ribotypes. Staphyloccus aureus isolates showed greater genetic diversity, whereas EcoR Ⅰ digestion of 49 different isolates yielded 31 different ribotypes. Conclusion Unique Salmonella and Staphylococcus aureus isolates could be identified through ribotyping. Although Salmonella serotyping and ribotyping were not strongly correlated, the combination of both restriction enzymes could be used to more effectively identify the genetic relationship among different strains as well as the source of food poisoning. Thus, not only could the genetic relationships amongst the different strains be inferred through ribotyping skills, the source of food poisoning and mode of transmission could also be determined under the use of this method.

Surveillance on Salmonella infection in Guangdong province, 2008-2009 / 中华流行病学杂志

Objective To understand the infection of Salmonella (S.) in patients with diarrhea and outbreaks caused by Salmonella to identify the serotypes, resistance to antibiotics and PFGE types of the strains from the surveillance program in Guangdong province. Methods S. strains from patients with diarrhea were detected, and all the positive strains collected in routine and outbreak surveillance programs, were tested by serum agglutination, antibiotic susceptibility and PFGE.Results 71 S. strains were isolated from 1922 stool samples in 2008, with positive rate as 3.7%.85 S. strains were isolated from 2110 stool samples in 2009, with positive rate as 4.0%. All the 156 strains were divided into 37 serotypes, with S. serotype typhimurium and enteritidis as the most common serotypes. 10 incidents of food poisoning were detected, of which 4 were caused by enteritidis and 3 by typhimurium. A suspected outbreak by enteritidis was discovered and under epidemiological investigation. The findings indicated that 2 of the 4 patients from this outbreak were infected with identical enteritidis isolates. 80% of the 229 isolates were found susceptible to cephalosporins and quinoione and 59.3% of them were muitiresistant to the antibiotics. Conclusion S. enteritidis and S. typhimurium were the most common serotypes that caused infectious diarrhoea and food poisoning in Guangdong province.

Surveillance program on and the distribution related to the virulence-associated genes of Vibrio cholerae in estuary of Pearl River / 中华流行病学杂志

Objective To understand the distribution,molecular characteristics and virulence genes of the O1 and O139 Vibrio cholerae isolates from the Pearl River Estuary water.Methods Vibrio cholerae isolates collected from the Pearl River estuary waters from January 2009 to December 2010,were tested by PCR for eight virulence-related genes,including cholera toxin(ctxA),zonula occludens toxin(zot),accessory cholera enterotoxin(ace),hemolysin(hlyA),toxin-coregulated pilus (tcpA),outer membrane protein(ompU),and the regulatory protein genes(tcpⅠ,toxR).Genetic relation was assessed by pulsed-field gel electrophoresis(PFGE)and the patterns were clustered by BioNumerics.Results From 1152 aquatic samples,69 isolates were identified,including 41 Inaba,18 Ogawa and 10 O139.All the isolates showed ctxA negative,while the hlyA and toxR genes were positive in all the isolates.34.15％(14/41)of the Inaba strains were hlyA + toxR + ompU + ace + zot + tcpI+,while 66.67％(12/18)belonged to Ogawa strains and 70％(7/10)of the O139 strains were hlyA + toxR+.Through PFGE analysis,the O1 isolates formed three clusters in this study.The patterns of O1 isolates differed widely,with the similarity as 72.8％-100.0％,while the patterns of O139 isolates having the similarity of 69.9％-95.5％.Conclusion The non-toxigenic O1 and O139 V.cholerae had a wide distribution in the environment of Pearl River estuary water during the nonepidemic period of cholera.All the aquatic isolates presented diversities on the related virulent genes.

Comparative study on the phenotypic characteristics and molecular typing of foodborne Vibrio parahaemolyticus in Guangdong province / 中华流行病学杂志

Objective To understand the phenotypic characteristics of foodbome Vibrio parahaemolyticus in Guangdong province through carrying out a comprehensive comparison including pulse field gel electrophoresis,ribotyping and serotyping.Methods 74 different Vibrio parahaemolyticus strains isolated from seafood and cases due to food poisoning in Guangdong province were under serotyping and susceptibility testing,in addition to the testing of direct heat hemolysin(tdh)and the heat hemolysin-related hemolysin hormone(trh)via PCR.Ribosomal genotyping(ribotyping)with EcoR Ⅰ restriction enzyme was utilized on 74 different Vibrio parahaemolyticus isolates,whereas pulsed-field gel electrophoresis(PFGE)with the Not Ⅰ restriction enzyme was used on 74 different Vibrio parahaemolyticus isolates.BioNumerics software was used to compare the isolates from different sources,times and places in order to elicit the correlation between different strains.Results Although Vibrio parahaemolyticus was 100.00％ sensitive to chloramphenicol,it still presented different levels of resistance against 13 other antibiotics.Among the 74 different strains of Vibrio parahaemolyticus under testing,24.32％ showed positive for the tdh virulence gene,whereas 4.05％ positive for trh.74 different Vibrio parahaemolyticus strains were found to belong to 26 serotypes,where the O5:K17 and O2:K28 serotypes were dominant in those isolates that causing seafood-poisoning.The O3:K6 serotype was found to be the dominant of those isolates that causing food-poisoning.Based on ribosomal genotyping,the 74 Vibrio parahaemolyticus isolates were divided into 62 different ribotypes,whereas the 74 strains of Vibrio parahaemolyticus were divided into 67 different PFGE types,thus exhibiting considerable genetic diversities of the strains.Conclusion Majority of the isolates causing food-poisoning carried tdh virulence gene.PFGE was shown to have the highest resolution,followed by ribotyping with serotyping being the lowest,where the combination of the three could improve the resolution.

Construction of recombinant adenovirus containing TK gene and its effect against human liver cancer cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a replication-defective adenovirus containing TK gene and investigate the killing effects of TK gene against human liver cancer cells SMMC-7721.</p><p><b>METHODS</b>The recombinant adenovirus ADV-TK was constructed using homologous recombination in the cells. SMMC-7721 cells transfected with recombined adenovirus were exposed to GCV, and the cell viability was measured by MTT assays.</p><p><b>RESULTS</b>The recombinant adenovirus containing TK gene was successfully constructed. Transfection by the recombinant adenovirus ADV-TK and GCV exposure significantly suppressed the growth of SMMC-7721 cells.</p><p><b>CONCLUSION</b>A replication-defective adenovirus containing TK gene has been successfully constructed, and in combination with GCV, the recombinant adenovirus produces significant killing effect against SMMC-7721 cells in vitro.</p>

Development of a DNA microarray for detecting 8 common species of food-borne bacterial pathogens in south China / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare a DNA Microarray that can detect 8 common species of food borne bacterial pathogens in south China.</p><p><b>METHODS</b>All the 70mer oligo probes were designed on the characteristic genome loci of the 8 species of food borne bacterial pathogens. Eight subarrays corresponding to the 8 food borne bacterial pathogens were spotted onto the slide and integrated into a pan-array on the chip. A number of identified and known bacterial samples from the storage bank were selected for the validation test.</p><p><b>RESULTS</b>Based on the PPR ranking, for LM sub-array, the PPR of the 3 Listeria bacteria LM, Lin and Liv was 68.8%, 51.8% and 59.6%, respectively, while that of the non-Listeria bacterial samples was all below 43%. For VC sub-array, the PPR of VC sample was 54.1% and that of the non-VC bacterial samples was lower than 17.2%. For VP sub-array, the PPR was 66.7% for VP sample and below 24.2% for non-VP bacterial samples. For Sal sub-array, the PPR was 55.9% for Sal sample and below 50.5% for non-Sal bacterial samples. For Shi sub-array, the PPR of Shi sample and the non-Shi bacterial samples was 53.8% and below 36.6%, respectively. For SA sub-array, the PPR of SA sample and non-SA bacterial samples was 65.2% and below 22.7%, respectively. For CJ sub-array, the PPR of the 2 Campylobacter bacteria CJ and CC were 88.2% and 58.8%, respectively, and that of the non-Campylobacter bacterial samples was lower than 35.3%. For EC sub-array, the PPR of EC sample was 47.9%, and that of the non-EC bacterial samples was lower than 41.6%. Evaluation of the Biosafood-8 chip developed in this study by 18 biological samples from different origins demonstrated its good specificity and accuracy in the identification of the pathogens.</p><p><b>CONCLUSION</b>The chip we developed can clearly differentiate the target food borne pathogenic bacteria and non-target bacteria and allows specific and accurate identification of the species of the tested bacteria isolates.</p>

Molecular characters of epidemic cerebrospinal W135 Neisseria meningitidis strain firstly isolated in Guangdong province / 中华预防医学杂志

<p><b>OBJECTIVE</b>To analyze the molecular characters of the W135 Neisseria meningitidis strain firstly isolated from patients in Guangdong province.</p><p><b>METHODS</b>Biochemical profile by using the API NH system (bio-Merieux, France) was used for confirmation,and sero-grouping of the meningococcal isolates including one serogroup W135, one serogroup C and three serogroups of a Neisseria meningitidis isolated from patients in Guangdong province in recent two years were performed. The subtype was determined after amplifying porA and porB respectively from the genome DNA of Neisseria meningitidis. Multilocus sequence typing (MLST) was performed for determining the allele profiles and the sequence types (STs). The polygenetic tree was obtained by analyzing the allele profiles with program Splits tree online. The molecular characters of the serogroup W135 Neisseria meningitidis was analyzed by its evolution relationship and the variable regions in porA and porB which encoding the outer membranes proteins (OMPs).</p><p><b>RESULTS</b>The subtype determined by porA variable regions of the serogroup W135 Neisseria meningitidis was P1.5,2, which was one of the most invasive types. The types of variable regions (VRs) I, IV, V, VII with porB were 1, 1, 1, 17, and there was no VI and VIII in porB. The allele profile of the W135 strain in this study was 2, 123, 4, 3, 8, 4, 6, and its sequence type was ST-2960, which belonged to ST-11/ET-37 clone complex. The subtypes of the serogroup C and serogroup A strains were P1.20, while their types of VR IV were all 7, and they all hadn't VR VII in porB. The strain serogroup C belonged to ST-4821 clone complex, and the 3 serogroup A strains belonged to ST-5 clone complex.</p><p><b>CONCLUSION</b>The molecular character of the serogroup W135 Neisseria meningitidis should be the same with the strains isolated in foreign country, and be different from the epidemic types in the area. This serogroup W135 Neisseria meningitis isolated from patients in Guangdong for the first time was thought to be a new type appearing in the local area.</p>

Investigation of human metapneumovirus in children with acute respiratory tract infections in Guangzhou areas / 中华预防医学杂志

<p><b>OBJECTIVE</b>To find out the status of human metapneumovirus (hMPV) infection in children under 14 years old with acute respiratory tract infections (ARI) in Guangzhou, analyze the epidemiology and clinical characteristics among the hMPV-infected children, and provide some basis for research of hMPV.</p><p><b>METHODS</b>All 521 throat and pharyngeal swabs were collected among the children with acute respiratory tract infections in outpatient departments and those admitted to the wards from September 2006 to August 2008. Then total nucleic acid was extracted from respiratory specimens. The 213 nucleosides of nucleoprotein gene were detected by RT-PCR and 16 strong positive samples were picked to compare with the sequence of hMPV in GenBank after the sequence of the amplification products were determined. Then applied statistical analysis to the data of the collected patients.</p><p><b>RESULTS</b>All 521 samples were detected by RT-PCR, and confirmed that N gene was positive in 39 samples with a detection rate of 7.49%, and the peak time was in October and April. The 16 amplification products were compared by using the analysis of gene sequence. The nucleocapsid protein (N) gene similarity to BJ1897 of Beijing was up to 99%, and to AY550156 of Thailand was up to 97%, genotype B was the most common genotype.</p><p><b>CONCLUSION</b>There existed hMPV infection in children acute respiratory system diseases in Guangzhou areas, in which the children under the age of 6 years were accounted for the main group, however there was no difference in gender. The main symptoms of the patients with hMPV infection were high fever and cough symptom of catarrh. Co-infections other than respiratory virus with hMPV were detected as 41.03% of positive samples.</p>

Surveillance and pathogenic analysis on non-typhoidal Salmonella in Guangdong province, 2007 / 中华流行病学杂志

Objective To understand non-typhoid Salmonella in diarrhea patients from Guangdong province in order to timely discover the outbreaks caused by them as well as to grasp the serotypes, antibiotic resistance and pulse-field gel electrophoresis (PFGE) types of those strains isolated from this surveillance program. Methods Salmonella strains from diarrhea patients were detected and all the positive strains were tested by serum agglutination, antibiotic susceptibility and PFGE. Results 71 nontyphoid Salmonella strains were isolated from 1128 stoop samples, with a positive rate of 6.29 %. All the strains were divided into 29 serotypes, with Salmonella serotype enteritidis and typhimurium showing the most common serotypes. Most of the strains were sensitive to cephalosporins and quinolones. The antibiotic resistance rates of S. typhimurium were higher than S. enteritidis and S. stanley. Other than S. enteritidis, all the serotype strains did not have the same type of PFGE. 17 S. enteritidis strains digested by Xba Ⅰ were divided to 8 PFGE types while the PFGE 4 type appeared the most common one. 12 S. enteritidis strains were typed again by Sfi Ⅰ and Not Ⅰ , and there were still 3 groups of strains showing the same PFGE pattern. Conclusion Most of the infection caused by non-typhoidal Salmonella was sporadic in Guangdong province in 2007. Cephalosporins and quinolones seemed the best in curing the infection of non-typhoidal Salmonella at the clinics.

MLST typing of Streptococcus suis isolated from clinical patients in Guangdong Province in 2005 / 南方医科大学学报

Intensive surveillance of human S.suis infection was carried out in July and August of 2005 in Guangdong Province, which coincided with the Sichuan outbreak. Five isolated cases of human infections were identified during this period, from which 5 S. suis serotype 2 isolates were recovered. MLST analysis showed that these 5 isolates shared identical sequences of 6 MLST housekeeping genes except for one point mutation found within the thrA gene fragment, a neutral mutation (TTA to TTG) in the third nucleotide (360 nt) of the codon for leucine. MLST analysis identified 2 sequence types in the Guangdong sporadic infection. Three Guangdong isolates L-SS002, L-SS003 and L-SS005 belonged to ST7, while the other two isolates L-SS004 and L-SS006 belonged to ST1, but they all belonged to ST1 clonal complex. This finding represents a striking feature that differs from the Sichuan outbreak caused by a single ST7 SS2 clone. The 3 isolates of ST7 were probably imported from Sichuan Province, while the origin of the other 2 isolates of ST1 still remain to be clarified.

The etiologic characteristics of Vibrio cholerae in Guangdong province in 2007 / 中华流行病学杂志

Objective To analyze the etiologic characteristics of Vibrio cholerae in Guangdong province in 2007.Genetic relationship was observed including among predominated biotype isolates from different areas within the province and among same biotypes isolates from cholera cases and regular surveillance.Methods Isolates from cholera cases and through environmental surveillance were typed by sero-and phage-typings.Similarity of molecular fingerprinting was analyzed through comparing the pulsed field gel electrophoresis(PFGE)pattern of predominated biotype isolates,and those of the same biotype isolates from cholera cases and environment surveillance,respectively.In addition,genetic relationship was determined by clustering analysis,using bionumerics software.Results In total,31 isolates from cholera cases were collected and subtyped for 3 serogroups.V.cholerae O1 El Tor Inaba phage 1d was the predominant biotype which causing most of the cases in Guangdong province in 2007.Data from cluster analysis showed that the similarity among Inaba phage 1d strains from different areas were from 94.5% to 100%.However.16 isolates were collected from environment surveillance programs and the predominated biotype could not be found.Additionally,the biotype distribution of cases isolates was not consistent with those isolates through surveillance.High phylogenetic diversity was observed for the same biotypes isolates from cases and surveillance samples.Conclusion Our data showed that V.cholerae O1 El Tor Inaba phage 1d was the predominated biotype with multi-clone coexisting and circulating in Guangdong province in 2007.It also appeared to be the characteristics of cholera in the non-epidemic period,suggesting that it was necessary to enhance the alert surveillance programs for cholera epidemic based on the molecular typing techniques.

Distribution and molecular characteristics of Vibrio cholerae serogroups O1 and O139 isolates in estuary of Pearl River / 中华流行病学杂志

<p><b>OBJECTIVE</b>Through systematic monitoring of the number and strain types of O1 and O139 Vibrio cholerae in the Pearl River estuary waters to analyze it's relevance with the temperature of environment, and the relevance between strains in water and isolates during outbreaks and epidemics as well as to estimate the methods used for environmental water detection and the potential role in cholera surveillance program.</p><p><b>METHODS</b>Twenty-four stations along the Pearl River were selected and the water samples were collected monthly from March 2006 to February 2007. V. cholerae O1 and O139 strains were isolated from the samples. Real-time PCR established in our laboratory was used to detect V. cholerae O1 and O139. Air temperature and water temperature were collected during sampling. Pulsed field gel electrophoresis (PFGE) was applied in molecular typing of the isolates.</p><p><b>RESULTS</b>862 water samples were collected during the study period. A total number of 77 O1 and O139 V. cholerae were isolated in 67 water samples and the positive rates were 7.77% for isolation and 26.33% for real-time PCR. Seasonal trend of positive rates by month were approximately coincident with the change of water temperature. The positive rates in the stations in urban area were higher than those in other areas. Toxigenic O139 strains were found in one station located in downstream of a marine market. Most of the O1 and O139 isolates were non-toxigenic. No trend of seasonal variation of the strains was noticed. Within these 75 isolates, 49 PFGE patterns were identified and the patterns differed widely with the similarity of 57.4% - 100%.</p><p><b>CONCLUSION</b>V. cholerae existed as the natural habitat in estuary water of the Pearl River and showed obvious genetic diversity. Data from monitoring waters might show the separation of strains with certain seasonal association. But the crowd did not show the relationship between the infections. Results from water surveillance program might provide indicators on the appearance of cholera pathogen which might be used in assessing the environmental risk of cholera epidemics as well as the alert of cholera.</p>

Molecular typing of Listeria monocytogenes isolated from foodstuff in Guangdong province by pulsed-field gel electrophoresis / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish molecular typing of Listeria monocytogenes isolates by pulsed-field gel electrophoresis (PFGE) for studying the epidemiologic characteristics of Listeria monocytogenes isolated from foodstuff in Guangdong province and to build up PFGE typing database of Listeria monocytogenes isolates for identifying the infectious resource of the outbreaks and other epidemiologic investigation.</p><p><b>METHODS</b>"Standardized Protocol for Molecular Subtyping of Listeria monocytogenes by PFGE" was followed. BioNumerics software was applied on image analysis, database establishment, comparative and corresponding analysis.</p><p><b>RESULTS</b>107 Listeria monocytogenes isolates were typed by PFGE, 41 PFGE types were observed among the isolates. The PFGE types were dispersive among these isolates. Listeria monocytogenes isolates were most frequently isolated in raw chicken while the most PFGE types were found in this type of food. The positive rate was relatively high in cold and iced foods. Only 1-2 DNA fragment difference occurred in 26 Listeria monocytogenes isolates by PFGE, so high degree of relatedness remained among these isolates. There were unique PFGE patterns in the regions of Shaoguan and Huizhou. From time to time, a number of isolates remained close relationship.</p><p><b>CONCLUSION</b>PFGE typing of the 107 Guangdong Listeria monocytogenes isolates demonstrated relative genetic diversity but a number of the isolates showed close relatedness.</p>

HLA-B Alleles Associated with Susceptibility or Resistance to Human Immunodeficiency Virus Type 1 in a Xinjiang Uygur Population, China / 中国病毒学

Host genetic factors, such as human leukocyte antigen (HLA) alleles, are important in Human immunod-eficiency virus (HIV) infection and its progression to AIDS. HLA class I genes, especially highly polymorphicHLA-B genes, are involved in the activation of HLA-restricted cytotoxic T lymphocytes (CTLs) against HIV, andthus control susceptibility to or protect against this virus. The present study was aimed to determine the distributionof HLA-B alleles in the Chinese Uygur ethnic group and its association with HIV infection. One hundred ten healthycontrol (HIV negative) and 128 HIV positive Chinese Xinjiang Uygur ethnic individuals were used in this study.HLA typing for B allele was performed by polymerase chain reaction (PCR) with sequence-specific primers (SSP).Hardy-Weinberg equilibrium was calculated using POPGENE software for the healthy control group. The HLA-Bfrequency of each allele was compared between the patients and the controls using the chi-square test. In HIV-1-pos-itive group, gene frequency of allele B * 4901 was significantly higher compared to the healthy control subjects (P=0.02, OR=3.06, 95%CI=1.16～8.10 forB*4901). In contrast, the gene frequency of B * 40 in healthy controlswas significantly higher than in the HIV-positive patients (P=0.02, OR=0.39, 95%CI=0.07～0. 92 for B* 40).In this study, HLA allele B * 4901 may be associated with increased susceptibility to HIV-1 infection, whereas the B* 40 allele may be associated with resistance to H HIV-1 infection.

Association of HLA-B alleles with human immunodeficiency virus type 1 infection in the Yi ethnic group in Sichuan province / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To determine the distribution of HLA-B alleles in the Chinese Yi ethnic group and its association with HIV infection.</p><p><b>METHODS</b>One hundred and six unrelated healthy HIV negative and 73 HIV positive Chinese Yi ethnic individuals were typed by PCR-SSP.</p><p><b>RESULTS</b>The frequency of alleles B*07, Bx 35, and B*46 were increased in HIV-1-positive subjects, whereas the alleles B*55, B*44 and B*78 were absent in the HIV-infected persons studied. The B*46 allele was present in a significantly higher gene frequency among HIV-1-positive individuals (P=0.02, OR=3.32, 95% CI=1.13-9.78) compared with control subjects.</p><p><b>CONCLUSION</b>HLA-B*46 may be associated with its susceptibility to HIV-1 infections.</p>

Genetic polymorphism of human immunodeficiency virus coreceptor CCR5Delta32 and CCR2-64I alleles in Chinese Yi Ethnic group in Sichuan / 中华流行病学杂志

<p><b>OBJECTIVE</b>To explore genetic polymorphisms CCR5 of HIV coreceptor and CCR2 in Chinese Yi Ethnic group in Sichuan.</p><p><b>METHODS</b>Genomic DNA samples were obtained from 119 healthy individuals and 88 HIV-1 infected individuals of Chinese Yi Ethnic group in Sichuan. Polymerase chain reaction (PCR), cloning and gene sequencing techniques were employed to identify the genotype of CCR5Delta32; PCR-restriction fragment length polymorphism (RFLP) and gene sequencing were employed to identify the CCR2-64I alleles.</p><p><b>RESULTS</b>At CCR5 locus, 2 heterozygotes (CCR5-wt/Delta32) and none homozygote (CCR5-Delta32/Delta32) were observed in 119 healthy individuals, allelic frequency of CCR5-Delta32 was 0.84%; No mutant was found in 88 HIV-1 infected individuals. At CCR2 locus, 26 heterozygotes (CCR2-64V/64I) and two homozygotes (CCR2-64I/64I) were observed in healthy individuals but the allelic frequency CCR2-64I was 12.61%. Among infected individuals, 12 heterozygotes (CCR2-64V/64I) and 7 homozygotes (CCR2-64I/64I) were observed and the allelic frequency CCR2-64I was 13.27%. Statistical analysis revealed that the differences of both loci between healthy and infected individuals were insignificant. Both loci were consistent with the Hardy-Weinberg equilibrium in the two different groups.</p><p><b>CONCLUSION</b>The polymorphism of CCR5Delta32 and CCR2-64I alleles from Chinese Yi Ethnic group was detected which was of significance for the evaluation of genetic resistance to HIV-1 infection in Chinese population.</p>

Manual microdissection of defined cells and RNA extraction for gene expression analysis of esophageal carcinoma progress / 中国医学科学院学报

<p><b>OBJECTIVES</b>To isolate cells of interest from heterogeneous tissue blocks to obtain accurate representations of molecular alterations acquired by neoplastic cells so as to meet the demands of further study on gene expression patterns of the esophageal carcinoma (EC) evolution.</p><p><b>METHODS</b>Blocks of EC were stored at -70 degrees C as close as possible to the time of surgical resection. The tissue block was embedded in OCT and frozen sections of 35 microns in thickness were cut in a cryostat under strict RNAse-free conditions. Individual frozen sections were mounted on plain glass slides and 30-gauge needle attached to a 1 ml syringe was used to microdissect defined cells in the sections. The procured cells were used for total RNA extraction.</p><p><b>RESULTS</b>An optimized protocol of manual microdissection was developed successfully whereby regions with an area as small as 1/25 mm2 could be accurately dissected. The RNA recovered from procured cells was of high quality suitable for subsequent applications of molecular analysis as assessed of 18S and 28S rRNAs by electrophoresis on agarose gel.</p><p><b>CONCLUSIONS</b>It is believed that manual microdissection is capable to procure defined cell populations from complex primary tissues, thus allowing investigation of tissue-, cell-, and function-specific gene expression patterns. The technique is simple, easy to perform, versatile, and of particular usefulness when laser capture microdissection (LCM) is practically unavailable.</p>