Research Center for Pathogens Detection Technology of Emerging Infectious Diseases

Guangzhou, China

Research Center for Pathogens Detection Technology of Emerging Infectious Diseases

Guangzhou, China
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Sun J.,Guangdong Provincial Institute of Public Health | Ning D.,Guangdong Provincial Institute of Public Health | Cai W.,Sun Yat Sen University | Zhou H.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | And 7 more authors.
Journal of Microbiological Methods | Year: 2017

End-point assays of in vitro cell proliferation and death have been employed to study the mechanisms of fungal pathogenesis and have shown the responses of host cells at individual time points. A new cell analysis technology has been developed that allows for the continuous measurement and quantification of cell activities, thus enabling the dynamic assessment of electrical impedance when various pathogens are cultured in vitro. In this study, this system was evaluated to determine the response of the cell line RAW264.7 to infection by several clinically relevant fungi in vitro, including Aspergillus fumigatus, Candida albicans, and melanized and albino mutant strains of Fonsecaea monophora. The results showed that infection resulted in rounding of the host cells with a loss of contact between individual cells and a decline in the electrical impedance of all test groups. However, changes in the electrical impedance were variable. Aspergillus fumigatus caused initial increases and later significant decreases in the electrical impedance, while for C. albicans and F. monophora, the effect was reduced. The melanized strain of F. monophora caused a faster change in the electrical impedance than the albino strain. Our data proved that this system can be used as an efficient tool for monitoring cellular responses to fungal infection. © 2017


Gao S.,Shanxi University | Gao S.,South China Agricultural University | Kang Y.,South China Agricultural University | Kang Y.,Sun Yat Sen University | And 10 more authors.
Frontiers in Microbiology | Year: 2017

Since April 2014, new infections of H5N6 avian influenza virus (AIV) in humans and domestic poultry have caused considerable economic losses in the poultry industry and posed an enormous threat to human health worldwide. In previous research using gene sequence and phylogenetic analysis, we reported that H5N6 AIV isolated in February 2015 (ZH283) in Pallas's sandgrouse was highly similar to that isolated in a human in December 2015 (A/Guangdong/ZQ874/2015), whereas a virus (i.e., SW8) isolated in oriental magpie-robin in 2014 was highly similar to that of A/chicken/Dongguan/2690/2013 (H5N6). However, the pathogenicity, transmissibility, and host immune-related response of chickens infected by those wild bird-origin H5N6 AIVs remain unknown. In response, we examined the viral distribution and mRNA expression profiles of immune-related genes in chickens infected with both viruses. Results showed that the H5N6 AIVs were highly pathogenic to chickens and caused not only systemic infection in multiple tissues, but also 100% mortality within 3-5 days post-infection. Additionally, ZH283 efficiently replicated in all tested tissues and transmitted among chickens more rapidly than SW8. Moreover, quantitative real-time polymerase chain reaction analysis showed that following infection with H5N6, AIVs immune-related genes remained active in a tissue-dependent manner, as well as that ZH283 induced mRNA expression profiles such as TLR3, TLR7, IL-6, TNF-α, IL-1β, IL-10, IL-8, and MHC-II to a greater extent than SW8 in the tested tissues of infected chickens. Altogether, our findings help to illuminate the pathogenesis and immunologic mechanisms of H5N6 AIVs in chickens. © 2017 Gao, Kang, Yuan, Ma, Xiang, Wang, Dai, Wang, Xiao, Liao and Ren.


Kang Y.,South China Agricultural University | Kang Y.,Sun Yat Sen University | Kang Y.,Key Laboratory of Animal Vaccine Development | Yuan R.,South China Agricultural University | And 21 more authors.
Oncotarget | Year: 2017

Viral infection activates a host's cellular phosphatidylinositol 3-kinase (PI3K)/ Akt signaling pathway, which is involved in cell differentiation, growth, survival, and apoptosis. To elucidate molecular mechanisms in the pathogenesis of Newcastle disease virus (NDV), we demonstrated that NDV transiently activates the PI3K/Akt pathway in chicken cells at an early phase of infection. Its activation was observed as early as 15 min post-infection and gradually weakened after 24 h. Incubating cells with a PI3K inhibitor, LY294002 or wortmannin, prior to NDV infection decreased NDV progeny yields and suppressed Akt phosphorylation at early times post-infection. Akt activation is triggered by NDV-GM or NDV-F48E9 and is abolished by methyl ß-cyclodextrin and chlorpromazine. Treatment following NDV-La Sota infection had no obvious effect. However, inhibiting PI3K activation promoted apoptotic responses during an early stage of NDV infection. The pan caspase inhibitor ZVAD-FMK mitigated the reduction in Akt phosphorylation by inhibiting PI3K activation, which indicates the signaling pathway promotes cell survival and, in turn, facilitates viral replication. By suppressing premature apoptosis upon NDV infection, the PI3K/Akt pathway enhances the anti-apoptotic response.


PubMed | Griffith University, Research Center for Pathogens Detection Technology of Emerging Infectious Diseases and China Institute of Technology
Type: | Journal: Scientific reports | Year: 2015

Enterovirus A71 (EVA71) and Coxsackievirus A16 (CVA16) are regarded as the two major causative pathogens in hand, foot and mouth disease (HFMD) epidemics. However, CVA6, previously largely ignored, became the predominant pathogen in China in 2013. In this study, we describe the epidemiological trends of CVA6 during the annual HFMD outbreaks from 2008 to 2013 in Guangdong, China. The study results show that CVA6 has been one of three major causative agents of HFMD epidemics since 2009. The periodic rotation and dominance of the three pathogens, EVA71, CVA16 and CVA6, may have contributed to the continuously increasing HFMD epidemics. Moreover, phylogenetic analysis of the VP1 gene shows that major circulating CVA6 strains collected from 2009 to 2013 are distinct from the earlier strains collected before 2009. In conclusion, the discovery from this research investigating epidemiological trends of CVA6 from 2008 to 2013 explains the possible pattern of the continuous HFMD epidemic in China. The etiological change pattern also highlights the need for improvement for pathogen surveillance and vaccine strategies for HFMD control in China.


Liang L.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | Ni H.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | Zhang X.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | Zeng X.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | And 5 more authors.
Chinese Journal of Microbiology and Immunology (China) | Year: 2015

Objective: To study the evolution and variation of the genes encoding hemagglutinin (HA) proteins of H3N2 influenza virus strains prevalent in Guangdong during 2011-2015. Methods: Forty-eight H3N2 influenza virus strains prevalent in Guangdong during 2011-2015 were recruited in this study by using time-space sampling. The nucleotide sequences of HA genes of those strains were sequenced and compared with those of the H3N2 influenza virus strains prevalent worldwide. The mutations and antigenic variations in HA genes of Guangdong strains were analyzed by MEGA 5.05, BEAST v1.7.0 and BioEdit7.1.3. Results: The 48 H3N2 influenza virus strains prevalent in Guangdong shared 96.4%-100.00% homologies in nucleotide sequences. The Guangdong strains isolated during 2013-2015 shared 97.8%-98.7% homologies in nucleotide sequences with the southern hemisphere vaccine strain A/Switzerland/9715293/2013. Phylogenetic analysis showed that the evolution was upward along the main branch over time. The Guangdong strains mainly distributed in clade 3C.3a with some of the 2015 strains in clade 3C.2a. A total of 330 nucleotide mutations were detected in the HA genes of H3N2 influenza virus strains prevalent during 2011-2015 as compared with the HA gene of the vaccine strain A/Texas/50/2012, resulting in 116 amino acid mutations with 12 of them associating with 4 epitope mutations. The N241D (N225D) and K192C mutations located in the receptor binding sites (RBS) and the 190 helix of RBS, respectively. Conclusion: Amino acid mutations occurred in the antigenic epitopes of HA proteins of H3N2 influenza virus strains prevalent in Guangdong province during 2011-2015, which might give rise to antigenic drift resulting in the outbreak of influenza. Thus, it is necessary to strengthen the surveillance for influenza pathogens. Copyright © 2015 by the Chinese Medical Association.


PubMed | Research Center for Pathogens Detection Technology of Emerging Infectious Diseases, Sun Yat Sen University and South China Agricultural University
Type: | Journal: Frontiers in microbiology | Year: 2016

First identified in May 2014 in Chinas Sichuan Province, initial cases of H5N6 avian influenza virus (AIV) infection in humans raised great concerns about the viruss prevalence, origin, and development. To evaluate both AIV contamination in live poultry markets (LPMs) and the risk of AIV infection in humans, we have conducted surveillance of LPMs in Guangdong Province since 2013 as part of environmental sampling programs. With environmental samples associated with these LPMs, we performed genetic and phylogenetic analyses of 10 H5N6 AIVs isolated from different cities of Guangdong Province from different years. Results revealed that the H5N6 viruses were reassortants with hemagglutinin (HA) genes derived from clade 2.3.4.4 of H5-subtype AIV, yet neuraminidase (NA) genes derived from H6N6 AIV. Unlike the other seven H5N6 viruses isolated in first 7 months of 2014, all of which shared remarkable sequence similarity with the H5N1 AIV in all internal genes, the PB2 genes of GZ693, GZ670, and ZS558 more closely related to H6N6 AIV and the PB1 gene of GZ693 to the H3-subtype AIV. Phylogenetic analyses revealed that the environmental H5N6 AIV related closely to human H5N6 AIVs isolated in Guangdong. These results thus suggest that continued reassortment has enabled the emergence of a novel H5N6 virus in Guangdong, as well as highlight the potential risk of highly pathogenic H5N6 AIVs in the province.


PubMed | China University of Technology, Southern Medical University, Research Center for Pathogens Detection Technology of Emerging Infectious Diseases and Chinese National Institute for Communicable Disease Control and Prevention
Type: | Journal: Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases | Year: 2015

Chinas Guangdong Province is located along the same latitude as Kolkata, India and Dhaka, Bangladesh, and is also considered a source of epidemic cholera. However, molecular description and the genetic relationships between Vibrio cholerae O1 El Tor isolates in Guangdong remain unclear. In this study, 381 clinical V. cholerae O1 isolates recovered from cholera cases presenting in Guangdong between 1961 and 2013 were investigated by PCR, amplicon sequencing and pulsed-field gel electrophoresis (PFGE). During this time frame, four distinct epidemic periods (1-4) were observed based on the different dominant serotype leading its epidemic, correspond to years; or time periods from/to 1961-1969, 1978-1989, 1990-2000, 2001-2013, respectively. Molecular analysis of representative isolates indicated that a single dominating clone was associated with each epidemic stage. All isolates from periods 1 and 2 carried the typical El Tor ctxB; this allele was displaced by classical ctxB beginning in 1993. However all isolates carried the El Tor-specific toxin-coregulated pili subunit A (tcpA). Isolates were grouped into five clusters on the basis of Not I enzyme digested PFGE, and the first four clusters were associated with specific periods, cluster I (period 1), II (period 3), III (period 2) and IV (period 4), respectively. While cluster V consisted of isolates from all four epidemic periods, but was most heterogeneous in appearance. Our data indicate genetic variations that shape the relationship among emerging isolates of V. cholerae O1 in Guangdong Province contribute to the 7th global pandemic.


PubMed | Research Center for Pathogens Detection Technology of Emerging Infectious Diseases, Southern Medical University and Chinese National Institute for Communicable Disease Control and Prevention
Type: Journal Article | Journal: Epidemiology and infection | Year: 2016

Vibrio cholerae O139 emerged as a causative agent of epidemic cholera in 1992 in India and Bangladesh, and was subsequently reported in China in 1993. The genetic relatedness and molecular characteristics of V. cholerae O139 in Guangdong Province, located in the southern coastal area of China, remains undetermined. In this study, we investigated 136 clinical V. cholerae O139 isolates from 1993 to 2013 in Guangdong. By conventional PCR, 123 (904%) isolates were positive for ctxB, ace and zot. Sequencing of the positive amplicons indicated 113 (917%) isolates possessed the El Tor allele of ctxB (genotype 3); seven carried the classical ctxB type (genotype 1) and three harboured a novel ctxB type (genotype 5). With respect to tcpA, 123 (904%) isolates were positive for the El Tor allele. In addition, pulsed-field gel electrophoresis (with NotI digestion) differentiated the isolates into clusters A and B. Cluster A contained seven of the non-toxigenic isolates from 1998 to 2000; another six non-toxigenic isolates (from 1998 and 2007) and all of the toxigenic isolates formed cluster B. Our results suggest that over a 20-year period, the predominant O139 clinical isolates have maintained a relatively tight clonal structure, although some genetic variance and shift has occurred. Our data highlight the persistence of toxigenic V. cholerae O139 in clinical settings in the southern coastal area of China.


Kang Y.,South China Agricultural University | Kang Y.,Key Laboratory of Animal Vaccine Development | Kang Y.,Key Laboratory of Zoonosis Prevention and Control of Guangdong Province | Li Y.,South China Agricultural University | And 21 more authors.
Frontiers in Microbiology | Year: 2015

Though previous studies have identified two strains of duck-origin Newcastle disease virus (NDV) with varying levels of pathogenicity, the relationship between the early-phase host innate immune response, and pathogenesis of ducks infected with these strains in the lungs and thymuses remains unclear. In this study, we compared the viral distribution and mRNA expression of immune-related genes in ducks following infection with two NDV strains, Duck/CH/GD/SS/10 (SS-10) and Duck/CH/GD/NH/10 (NH-10). Both NDV strains replicated systemically in tested tissues (i.e., small intestine, cecal tonsils, brain, lung, bursa of Fabricius, thymus, and spleen) and exhibited different biological properties in duck pathogenicity. Real-time quantitative polymerase chain reaction showed that the expression of TLR3, TLR7, RIG-I, MDA5, IL-1β, IL-2, IL-6, IL-8, IFN-alpha, IFN-beta, IFN-gamma in the lungs was significantly greater than in the respective thymus genes during the early post infection stage. However, in the lungs, the expression of TLR3, TLR7, IL-1β, IL-2, IL-8, IFN-alpha, IFN-gamma, and MHC II induced by SS-10 at 72 h post-inoculation (hpi) was less than with NH-10. Furthermore, the expression of IL-6 and IFN-beta in the lungs and thymuses following infection with SS-10 was greater than that with NH-10 at 24 and 48 hpi. These results highlight important differences in host innate immune responses, courses of infection, and pathogenesis following NDV infection. Further studies should work to expand understandings of the molecular mechanisms related to NDV infection. © 2015 Kang, Li, Yuan, Feng, Xiang, Sun, Li, Xie, Tan and Ren.


Yuan R.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | Yuan R.,World Health Organization | Yuan R.,South China Agricultural University | Zou L.,Research Center for Pathogens Detection Technology of Emerging Infectious Diseases | And 19 more authors.
Frontiers in Microbiology | Year: 2016

Since early 2013, H7N9-subtype avian influenza virus (AIV) has caused human infection in eastern China. To evaluate AIV contamination and the public risk of infection, we systematically implemented environmental sampling from live poultry markets in Guangdong Province. Through real-time polymerase chain reaction assays and next-generation sequencing, we generated full nucleotide sequences of all 10 H6N6 AIVs isolated during sampling. Focusing on sequence analyses of hemagglutinin genes of the 10 H6N6 AIVs revealed that the viruses were low pathogenic AIVs with the typical hemagglutinin cleavage site of P-Q-I-E-T-R-G. The hemagglutinin, neuraminidase, and nucleocapsid genes of nine AIVs were of ST2853-like (H6-subtype) lineage, ST192-like (N6-subtype) lineage, and HN573-like (H6-subtype) lineage, respectively; whereas the other five genes were of ST339-like (H6-subtype) lineage. However, the polymerase PB2 and nucleocapsid genes of one strain (HZ057) were of GS/GD-like (H5N1-subtype) and ST339-like lineages. Phylogenic analysis revealed that all eight genes of the 10 viruses belonged to Eurasian avian lineage. Altogether, the 10 AIVs were reassortants of different genetic groups of exchanges with the same virus subtype, thus illustrating the genetic diversity and complexity of H6N6-subtype AIVs in Guangdong Province. © 2016 Yuan, Zou, Kang, Wu, Zeng, Lu, Liang, Song, Zhang, Ni, Lin, Liao and Ke.

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