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Ling N, Li Z, Wang Y, Wu Q, Ye Y, Zhang J. LuxS-deficiency reduces persistence of Cronobacter to low-moisture but contributes to virulence after rehydration. Food Res Int 2023; 174:113642. [PMID: 37986541 DOI: 10.1016/j.foodres.2023.113642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/21/2023] [Accepted: 10/24/2023] [Indexed: 11/22/2023]
Abstract
Low-moisture foods (LMF) have arisen an increasing concern as vehicles of foodborne pathogens. Cronobacter genus, a class A pathogen in powdered infant formula (PIF), is crucial to the safety of LMF. Researchers have concentrated more on the bacterial survival caused by key hazardous factors, yet they often ignore the alteration of virulence properties in the surviving strains following rehydration of LMF mediated by the key factors. Our previous transcriptional profiling showed that luxS might participate in desiccation response. Herein, we further investigated the role of Cronobacter LuxS under desiccation stress by combining with the phenotypic and gene analysis between the Cronobacter parent and luxS mutant strains. Desiccation stress destructing assays confirmed that luxS can significantly enhance the resistance of Cronobacter towards desiccation. Our results also showed that cell hydrophobicity, aggregation, motility, the content of polysaccharide, and AI-2 synthesis pathway involved in luxS-mediated desiccation response. The luxS mutant strain exhibited higher swimming and swarming motility, more content of capsular polysaccharide, and more rapid of aggregation, but lower hydrophobicity than that of the wild-type strain, whereas desiccation stress would result in a opposite effect on these cell surface properties in ΔluxS during rehydration. Additionally, the comparation of gene expression profiles indicated that low moisture would trigger Cronobacter luxS to promote transport osmoprotectants by regulating the expression of proX, proW, and treC, and suppress the expression of cpsG associated with polysaccharide colanic acid. Notably, this study also discovered for the first time that the luxS-deficiency dramatically attenuated adhesion and invasion to intestinal and brain cells, but ΔluxS subjected to desiccation could aggravate the cell virulence instead. Therefore, thinking the alteration of toxicity caused by low-moisture, approach based on blocking the expression of the luxS gene to prevent Cronobacter in LMF needs to be adopted with caution.
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Affiliation(s)
- Na Ling
- Provincial Key Laboratory of Microbial Safety and Health, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Zongyang Li
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yuhang Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Qingping Wu
- Provincial Key Laboratory of Microbial Safety and Health, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China
| | - Yingwang Ye
- Provincial Key Laboratory of Microbial Safety and Health, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China; School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China.
| | - Jumei Zhang
- Provincial Key Laboratory of Microbial Safety and Health, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, China.
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Parra-Flores J, Flores-Soto F, Flores-Balboa C, Alarcón-Lavín MP, Cabal-Rosel A, Daza-Prieto B, Springer B, Cruz-Córdova A, Leiva-Caro J, Forsythe S, Ruppitsch W. Characterization of Cronobacter sakazakii and Cronobacter malonaticus Strains Isolated from Powdered Dairy Products Intended for Consumption by Adults and Older Adults. Microorganisms 2023; 11:2841. [PMID: 38137986 PMCID: PMC10745994 DOI: 10.3390/microorganisms11122841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 11/09/2023] [Accepted: 11/19/2023] [Indexed: 12/24/2023] Open
Abstract
The objective of this study was to characterize Cronobacter spp. and related organisms isolated from powder dairy products intended for consumption by adults and older adults using whole-genome sequencing (WGS), and to identify genes and traits that encode antibiotic resistance and virulence. Virulence (VGs) and antibiotic resistance genes (ARGs) were detected with the Comprehensive Antibiotic Resistance Database (CARD) platform, ResFinder, and MOB-suite tools. Susceptibility testing was performed using disk diffusion. Five presumptive strains of Cronobacter spp. were identified by MALDI-TOF MS and ribosomal MLST. Three C. sakazakii strains were of the clinical pathovar ST1, one was ST31, and the remaining isolate was C. malonaticus ST60. In addition, Franconibacter helveticus ST345 was identified. The C. sakazakii ST1 strains were further distinguished using core genome MLST based on 2831 loci. Moreover, 100% of the strains were resistant to cefalotin, 75% to ampicillin, and 50% to amikacin. The C. sakazakii ST1 strains were multiresistant (MDR) to four antibiotics. Additionally, all the strains adhered to the N1E-115 cell line, and two invaded it. Eighteen ARGs mainly involved in antibiotic target alteration and antibiotic efflux were detected. Thirty VGs were detected and clustered as flagellar proteins, outer membrane proteins, chemotaxis, hemolysins, and genes involved in metabolism and stress. The pESA3, pSP291-1, and pCMA1 plasmids were detected, and the prevalent mobile genetic elements (MGEs) were ISEsa1, ISEc52, and IS26. The isolates of C. sakazakii and C. malonaticus exhibited multiresistance to antibiotics, harbored genes encoding various antibiotic resistance proteins, and various virulence factors. Consequently, these contaminated powdered dairy products pose a risk to the health of hypersensitive adults.
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Affiliation(s)
- Julio Parra-Flores
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán 3800708, Chile;
| | - Fernanda Flores-Soto
- Nutrition and Dietetics School, Universidad del Bío-Bío, Chillán 3800708, Chile; (F.F.-S.); (C.F.-B.)
| | - Carolina Flores-Balboa
- Nutrition and Dietetics School, Universidad del Bío-Bío, Chillán 3800708, Chile; (F.F.-S.); (C.F.-B.)
| | - María P. Alarcón-Lavín
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán 3800708, Chile;
| | - Adriana Cabal-Rosel
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, 1220 Vienna, Austria; (A.C.-R.); (B.D.-P.); (B.S.); (W.R.)
| | - Beatriz Daza-Prieto
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, 1220 Vienna, Austria; (A.C.-R.); (B.D.-P.); (B.S.); (W.R.)
| | - Burkhard Springer
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, 1220 Vienna, Austria; (A.C.-R.); (B.D.-P.); (B.S.); (W.R.)
| | - Ariadnna Cruz-Córdova
- Intestinal Bacteriology Research Laboratory, Hospital Infantil de México Federico Gómez, Mexico City 06720, Mexico;
| | - José Leiva-Caro
- Department of Nursing, Universidad del Bío-Bío, Chillán 3800708, Chile;
| | - Stephen Forsythe
- FoodMicrobe.com Ltd., Adams Hill, Keyworth, Nottingham NG12 5GY, UK
| | - Werner Ruppitsch
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, 1220 Vienna, Austria; (A.C.-R.); (B.D.-P.); (B.S.); (W.R.)
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3
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Wang Y, Ling N, Jiao R, Zhang X, Ren Y, Li H, Zhao W, Wu Q, Ye Y. Transcriptomic analysis reveals novel desiccation tolerance mechanism of Cronobacter based on type VI secretion system inhibition. Food Res Int 2023; 172:113143. [PMID: 37689845 DOI: 10.1016/j.foodres.2023.113143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 06/12/2023] [Accepted: 06/13/2023] [Indexed: 09/11/2023]
Abstract
Cronobacter malonaticus (C. malonaticus) is a food-borne pathogen inducing severe infections both in infants and adults, and it could survive in dry powdered infant formula (PIF) for a long time, implying its strong tolerance to desiccation. However, the thorough molecular mechanism of resistance to desiccation remains elusive. When C. malonaticus was exposed to desiccation conditions (7, 15, and 30 d), transcriptomic analysis provided a universal adaptation strategy to withstand desiccation with the increased compatible solutes accumulation, activated stress resistance-related regulators, suppressed protein export and bacterial secretion system, and reduced other unessential survival functions including adhesion, invasion, virulence, and flagellar motility. Importantly, type VI secretion system (T6SS) genes exhibited significantly downregulated expressions, as well as markedly increased survival and viability of their mutants after desiccation treatment, revealing the negative regulation of T6SS in desiccation tolerance. Meanwhile, the decreased expressions of T6SS structure genes in other six species further confirmed the vital role of T6SS in desiccation tolerance of Cronobacter spp. Thus, our studies present a novel hypothesis of desiccation resistance in Cronobacter based on type VI secretion system inhibition, causing the reduction of macromolecule secretion such as effectors and hyperosmolality development within the cytomembrane, which allow Cronobacter to survive in desiccation.
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Affiliation(s)
- Yang Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Na Ling
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Rui Jiao
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Xiyan Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Yuwei Ren
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Hui Li
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Wenhua Zhao
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China
| | - Yingwang Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China.
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Parra-Flores J, Holý O, Acuña S, Lepuschitz S, Pietzka A, Contreras-Fernández A, Chavarría-Sepulveda P, Cruz-Córdova A, Xicohtencatl-Cortes J, Mancilla-Rojano J, Castillo A, Ruppitsch W, Forsythe S. Genomic Characterization of Cronobacter spp. and Salmonella spp. Strains Isolated From Powdered Infant Formula in Chile. Front Microbiol 2022; 13:884721. [PMID: 35722296 PMCID: PMC9201451 DOI: 10.3389/fmicb.2022.884721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/04/2022] [Indexed: 11/14/2022] Open
Abstract
This study characterized five Cronobacter spp. and six Salmonella spp. strains that had been isolated from 155 samples of powdered infant formula (PIF) sold in Chile and manufactured in Chile and Mexico in 2018–2020. Two strains of Cronobacter sakazakii sequence type (ST) ST1 and ST31 (serotypes O:1 and O:2) and one strain of Cronobacter malonaticus ST60 (O:1) were identified. All Salmonella strains were identified as Salmonella Typhimurium ST19 (serotype O:4) by average nucleotide identity, ribosomal multilocus sequence typing (rMLST), and core genome MLST (cgMLST). The C. sakazakii and C. malonaticus isolates were resistant to cephalothin, whereas the Salmonella isolates were resistant to oxacillin and ampicillin. Nineteen antibiotic resistance genes were detected in the C. sakazakii and C. malonaticus isolates; the most prevalent were mcr-9.1, blaCSA, and blaCMA. In Salmonella, 30 genes encoding for aminoglycoside and cephalosporin resistance were identified, including aac(6′)-Iaa, β-lactamases ampH, ampC1, and marA. In the Cronobacter isolates, 32 virulence-associated genes were detected by WGS and clustered as flagellar proteins, outer membrane proteins, chemotaxis, hemolysins, invasion, plasminogen activator, colonization, transcriptional regulator, survival in macrophages, use of sialic acid, and toxin-antitoxin genes. In the Salmonella strains, 120 virulence associated genes were detected, adherence, magnesium uptake, resistance to antimicrobial peptides, secretion system, stress protein, toxin, resistance to complement killing, and eight pathogenicity islands. The C. sakazakii and C. malonaticus strains harbored I-E and I-F CRISPR-Cas systems and carried Col(pHHAD28) and IncFIB(pCTU1) plasmids, respectively. The Salmonella strains harbored type I-E CRISPR-Cas systems and carried IncFII(S) plasmids. The presence of C. sakazakii and Salmonella in PIF is a health risk for infants aged less than 6 months. For this reason, sanitary practices should be reinforced for its production and retail surveillance.
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Affiliation(s)
- Julio Parra-Flores
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán, Chile
| | - Ondřej Holý
- Science and Research Centre, Faculty of Health Sciences, Palacký University Olomouc, Olomouc, Czechia
| | - Sergio Acuña
- Department of Food Engineering, Universidad del Bío-Bío, Chillán, Chile
| | - Sarah Lepuschitz
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, Vienna, Austria
| | - Ariane Pietzka
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, Vienna, Austria
| | | | | | - Ariadnna Cruz-Córdova
- Intestinal Bacteriology Research Laboratory, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Juan Xicohtencatl-Cortes
- Intestinal Bacteriology Research Laboratory, Hospital Infantil de México Federico Gómez, Mexico City, Mexico
| | - Jetsi Mancilla-Rojano
- Intestinal Bacteriology Research Laboratory, Hospital Infantil de México Federico Gómez, Mexico City, Mexico.,Faculty of Medicine, Biological Sciences Graduate Program, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Alejandro Castillo
- Department of Nutrition and Food Science, Texas A&M University, College Station, TX, United States
| | - Werner Ruppitsch
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, Vienna, Austria
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Otake S, Okada Y, Forsythe SJ, Kasai M. Meningitis and brain abscess formation caused by Cronobacter malonaticus sequence type 440 in a full-term neonate. J Infect Chemother 2021; 27:1648-1652. [PMID: 34183235 DOI: 10.1016/j.jiac.2021.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 06/02/2021] [Accepted: 06/03/2021] [Indexed: 11/27/2022]
Abstract
Cronobacter spp. cause serious diseases, such as necrotizing enterocolitis, bacteremia, and meningitis in neonates and infants. Most Cronobacter-associated meningitis is reportedly due to C. sakazakii and the majority of infections caused by C. malonaticus occur in adults and are less severe. We report the case of meningitis and brain abscess caused by C. malonaticus Sequence Type (ST) 440 in a healthy full-term neonate. We should consider the possibility that full-term neonates may develop meningitis due to C. malonaticus and treat appropriately because its mortality rate is very high, and survivors are usually left with severe neurologic impairment. In addition, C. malonaticus ST440 may have virulence factors that cause neonatal meningitis akin to the previous report of meningitic ST307 strain.
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Affiliation(s)
- Shogo Otake
- Division of Infectious Disease, Department of Pediatrics, Hyogo Prefectural Kobe Children's Hospital, Japan.
| | - Yumiko Okada
- Division of Biomedical Food Research, National Institute of Health Sciences, Japan
| | | | - Masashi Kasai
- Division of Infectious Disease, Department of Pediatrics, Hyogo Prefectural Kobe Children's Hospital, Japan
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Wang X, Wang Y, Ling N, Shen Y, Zhang D, Liu D, Ou D, Wu Q, Ye Y. Effects of tolC on tolerance to bile salts and biofilm formation in Cronobacter malonaticus. J Dairy Sci 2021; 104:9521-9531. [PMID: 34099300 DOI: 10.3168/jds.2021-20128] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 03/29/2021] [Indexed: 12/21/2022]
Abstract
Bile salts is one of essential components of bile secreted into the intestine to confer antibacterial protection. Cronobacter species are associated with necrotizing enterocolitis in newborns and show a strong tolerance to bile salts. However, little attempt has been made to focus on the molecular basis of the tolerance to bile salts. In this study, we investigated the roles of tolC on growth, cell morphology, motility, and biofilm formation ability in Cronobacter malonaticus under bile salt stress. The results indicated that the absence of tolC significantly affected the colony morphology and outer membrane structure in a normal situation, compared with those of the wild type strain. The deletion of tolC caused the decline in resistance to bile salt stress, inhibition of growth, and observable reduction in relative growth rate and motility. Moreover, the bacterial stress response promoted the biofilm formation ability of the mutant strain. The expression of the AcrAB-TolC system (acrA, acrB, and tolC) was effectively upregulated compared with the control sample when exposed to different bile salt concentrations. The findings provide valuable information for deeply understanding molecular mechanisms about the roles of tolC under bile salt stress and the prevention and control of C. malonaticus.
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Affiliation(s)
- Xin Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yaping Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Na Ling
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yizhong Shen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Danfeng Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dengyu Liu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dexin Ou
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
| | - Yingwang Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China.
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Ling N, Wang X, Liu D, Shen Y, Zhang D, Ou D, Fan H, Wang J, Ding Y, Zhang J, Wu Q, Ye Y. Role of fliC on biofilm formation, adhesion, and cell motility in Cronobacter malonaticus and regulation of luxS. Food Chem Toxicol 2021; 149:111940. [PMID: 33417975 DOI: 10.1016/j.fct.2020.111940] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/07/2020] [Accepted: 12/17/2020] [Indexed: 12/29/2022]
Abstract
Cronobacter malonaticus is one of the important foodborne pathogens causing infections mainly in adults. Biofilm formation, adhesion, and motility in Cronobacter have been documented, but the implying molecular mechanism has received little attention. Here, a comparison in biofilm formation, adhesion ability, and cell motility among wild type (WT), △luxS, and △fliC strains were analyzed using scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM). The thickest biofilm was formed by WT, followed by △luxS and △fliC. Furthermore, the deletion of fliC caused the loss of cell motility and the failure to flagella biosynthesis and mature biofilm formation. Besides, the adhesion abilities of △luxS and △fliC to biotic cells (LoVo and IEC-6) and abiotic surface (glass) were significantly decreased compared to WT, revealing that fliC might have an important role in the organism's invasion properties. We further demonstrated that the expression of negative regulator (flgM) of flagellin in △luxS was higher than that in WT, which indicated that luxS indirectly contributed to fliC expression. Our findings provided a novel perspective for precaution and control of C. malonaticus through intercepting fliC-mediated adhesion to biotic cells and abiotic surface.
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Affiliation(s)
- Na Ling
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China; Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Xin Wang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dengyu Liu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Yizhong Shen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Danfeng Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Dexin Ou
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China
| | - Hongying Fan
- School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, 510515, China
| | - Juan Wang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Yu Ding
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Jumei Zhang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
| | - Yingwang Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, 230009, China; Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, 510070, China.
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Zhang M, Zhang X, Tong L, Ou D, Wang Y, Zhang J, Wu Q, Ye Y. Random Mutagenesis Applied to Reveal Factors Involved in Oxidative Tolerance and Biofilm Formation in Foodborne Cronobacter malonaticus. Front Microbiol 2019; 10:877. [PMID: 31118922 PMCID: PMC6504702 DOI: 10.3389/fmicb.2019.00877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 04/05/2019] [Indexed: 12/16/2022] Open
Abstract
Cronobacter species are linked with life-treating diseases in neonates and show strong tolerances to environmental stress. However, the information about factors involved in oxidative tolerance in Cronobacter remains elusive. Here, factors involved in oxidative tolerance in C. malonaticus were identified using a transposon mutagenesis. Eight mutants were successfully screened based on a comparison of the growth of strains from mutant library (n = 215) and wild type (WT) strain under 1.0 mM H2O2. Mutating sites including thioredoxin 2, glutaredoxin 3, pantothenate kinase, serine/threonine protein kinase, pyruvate kinase, phospholipase A, ferrous iron transport protein A, and alanine racemase 2 were successfully identified by arbitrary PCR and sequencing alignment. Furthermore, the comparison about quantity and structure of biofilms formation among eight mutants and WT was determined using crystal violet staining (CVS), scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Results showed that the biofilms of eight mutants significantly decreased within 48 h compared to that of WT, suggesting that mutating genes play important roles in biofilm formation under oxidative stress. The findings provide valuable information for deeply understanding molecular mechanism about oxidative tolerance of C. malonaticus.
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Affiliation(s)
- Maofeng Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China.,State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China
| | - Xiyan Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China
| | - Liaowang Tong
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China
| | - Dexin Ou
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China
| | - Yaping Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China
| | - Yingwang Ye
- School of Food Science and Engineering, Hefei University of Technology, Hefei, China.,State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China
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9
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Holý O, Cruz-Córdova A, Xicohtencatl-Cortes J, Hochel I, Parra-Flores J, Petrželová J, Fačevicová K, Forsythe S, Alsonosi A. Occurrence of virulence factors in Cronobacter sakazakii and Cronobacter malonaticus originated from clinical samples. Microb Pathog 2019; 127:250-6. [PMID: 30550840 DOI: 10.1016/j.micpath.2018.12.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 12/06/2018] [Accepted: 12/06/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND Cronobacter spp. are Gram-negative, facultative-anaerobic, non-spore forming, enteric coliform bacteria, which belongs to the Enterobacteriaceae family. Cronobacter spp. are opportunistic pathogens that have brought rare but life-threatening infections such as meningitis, necrotizing enterocolitis and bloodstream infections in neonates and infants. Information on the diversity, pathogenicity and virulence of Cronobacter species obtained from various sources is still relatively scarce and fragmentary. The aim of this study was to examine and analyse different pathogenicity and virulence factors among C. sakazakii and C. malonaticus strains isolated from clinical samples. METHODS The thirty-six clinical Cronobacter strains have been used in this study. This bacterial collection consists of 25 strains of C. sakazakii and 11 strains of C. malonaticus, isolated from different clinical materials. Seven genes (ompA, inv, sip, aut, hly, fliC, cpa) were amplified by PCR. Moreover, the motility and the ability of these strains to adhere and invade human colorectal adenocarcinoma (HT-29) and mouse neuroblastoma (N1E-115) cell lines were investigated. RESULTS Our results showed that all tested strains were able to adhere to both used cell lines, HT-29 and N1E-115 cells. The invasion assay showed that 66.7% (24/36) of isolates were able to invade N1-E115 cells while 83% (30/36) of isolates were able to invade HT-29 cells. On the average, 68% of the C. sakazakii strains exhibited seven virulence factors and only 18% in C. malonaticus. All strains amplified ompA and fliC genes. The other genes were detected as follow: sip 97% (35/36), hlyA 92% (33/36), aut 94% (34/36), cpa 67% (24/36), and inv 69% (25/36). CONCLUSIONS C. sakazakii and C malonaticus strains demonstrate the diversity of the virulence factors present among these pathogens. It is necessary to permanently monitor the hospital environment to appropriately treat and resolve cases associated with disease. Furthermore, in-depth knowledge is needed about the source and transmission vehicles of pathogens in hospitals to adopt pertinent prevention measures.
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Tong L, Zhang M, Zhang X, Wang Y, Ou D, Zhang J, Wu Q, Ye Y. Exploration of factors in response to low acid tolerance using random mutagenesis in Cronobacter malonaticus. Food Res Int 2018; 116:994-999. [PMID: 30717032 DOI: 10.1016/j.foodres.2018.09.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 08/26/2018] [Accepted: 09/13/2018] [Indexed: 11/25/2022]
Abstract
Cronobacter species are associated with rare but severe infections in newborns, and their tolerance to environmental stress such as acid stress has been described. However, the factors involved in low acid tolerance in Cronobacter are poorly understood. Here, a transposon mutagenesis approach was used to explore the factors involved in acid tolerance in C. malonaticus. Eight mutants from mutant library (n = 215) were successfully screened through a comparison of growth with wild type (WT) strain under acid stress (pH 4.0). Eight mutating sites including glucosyltransferase MdoH, extracellular serine protease, sulfate transporter, phosphate transporter permease subunit PstC, lysine transporter, nitrogen regulation protein NR (II), D-alanine-D-alanine ligase, glucan biosynthesis protein G were successfully identified by arbitrary polymerase chain reaction and sequencing. The biomass of biofilm of eight mutants were significantly reduced using crystal violet staining (CVS) compared with that of WT. furthermore, the more compact biofilms of WT was observed than those of eight mutants through scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Disassembly of biofilms appeared among mutants and WT strain from 48 h to 72 h through the increasing of dead cells and reduction of viable cells and exopolysaccharide. The study reveals the molecular basis involved in acid tolerance of C. malonaticus and a possible relationship between biofilm formation and acid tolerance, which provides valuable information for survival of C. malonaticus under acid stress.
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Affiliation(s)
- Liaowang Tong
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Maofeng Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Xiyan Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yaping Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Dexin Ou
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
| | - Yingwang Ye
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
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Zhang M, Zhang X, Tong L, Wang Y, Ou D, Zhang J, Wu Q, Ye Y. Genes involved in tolerance to osmotic stress by random mutagenesis in Cronobacter malonaticus. J Dairy Sci 2018; 101:3851-3858. [PMID: 29454685 DOI: 10.3168/jds.2017-13995] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Accepted: 12/28/2017] [Indexed: 12/18/2022]
Abstract
Cronobacter malonaticus is one of the opportunistic food-borne pathogens in powdered infant formula and has unusual abilities to survive under environmental stresses such as osmotic conditions. However, the genes involved in osmotic stress have received little attention in C. malonaticus. Here, genes involved in osmotic stress were determined in C. malonaticus using a transposon mutagenesis approach. According to the growth of mutants (n = 215) under 5.0% NaCl concentration, the survival of 5 mutants under osmotic stress was significantly decreased compared with that of the wild type strain. Five mutating sites, including potassium efflux protein KefA, inner membrane protein YqjF, peptidylprolyl isomerase, Cys-tRNA(Pro)/Cys-tRNA(Cys) deacylase, and oligogalacturonate lyase were successfully identified. In addition, the biofilm formation of 5 mutants was determined using crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy, and the biofilms of 5 mutants significantly decreased within 72 h compared with that of wild type strain. This is the first report to determine the genes involved in osmotic tolerance in C. malonaticus. The findings provided valuable information for deep understanding of the mechanism of survival of C. malonaticus under osmotic stress, and a possible relationship between biofilm formation and tolerance to osmotic stress was also demonstrated in C. malonaticus.
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Affiliation(s)
- Maofeng Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Xiyan Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Liaowang Tong
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Yaping Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Dexin Ou
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
| | - Yingwang Ye
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
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Aldubyan MA, Almami IS, Benslimane FM, Alsonosi AM, Forsythe SJ. Comparative Outer Membrane Protein Analysis of High and Low-Invasive Strains of Cronobacter malonaticus. Front Microbiol 2017; 8:2268. [PMID: 29204140 PMCID: PMC5698278 DOI: 10.3389/fmicb.2017.02268] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/03/2017] [Indexed: 01/25/2023] Open
Abstract
Cronobacter are an important group of foodborne pathogens that has been linked to life-threatening infections in both infants and adults. The major infections associated with Cronobacter species are neonatal meningitis, necrotizing enterocolitis, and septicaemia. There are seven species in the Cronobacter genus, of which only three are of clinical importance; Cronobacter sakazakii, Cronobacter malonaticus, and Cronobacter turicensis. To date most studies have focussed on C. sakazakii as it is the major species associated with neonatal infections. However, recently C. malonaticus, in particular sequence type 7 (ST7), has been noted as being prevalent in adult infections and therefore warranting further investigation. In this study, eight strains of C. malonaticus ST7, that had been isolated from a wide range of sources and varied in their in vitro virulence, were chosen for proteomic analysis of their outer membrane proteins (OMPs). One-dimensional gel analysis revealed a ~29 kDa size band that was only present in the highly invasive strains. Subsequent mass spectrometric analysis identified several peptides that matched the flagellin protein. The presence of flagellin protein was confirmed in 2D gel spot. Mass spectrometry analysis of total OMPs revealed that the four highly invasive C. malonaticus strains expressed the main flagellum proteins that were absent from the four low invasive strains. These were the flagellar hook protein FlgE, flagellar hook-associated protein 1, flagellar hook-associated protein, flagellin, and flagellar hook-filament junction protein FlgL. This data indicates that C. malonaticus flagellar proteins may have an important role in the organism's invasion properties.
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Affiliation(s)
- Maha A Aldubyan
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.,Department of Pharmacology, College of Pharmacy, Qassim University, Al-Qassim, Saudi Arabia
| | - Ibtesam S Almami
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.,Biology Department, College of Science, Qassim University, Al-Qassim, Saudi Arabia
| | - Fatiha M Benslimane
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom.,Biomedical Research Institute, Qatar University, Doha, Qatar
| | - Abdlrhman M Alsonosi
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Stephen J Forsythe
- School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
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Ye Y, Zhang M, Jiao R, Ling N, Zhang X, Tong L, Zeng H, Zhang J, Wu Q. Inactivation of Cronobacter malonaticus cells and inhibition of its biofilm formation exposed to hydrogen peroxide stress. J Dairy Sci 2017; 101:66-74. [PMID: 29102134 DOI: 10.3168/jds.2017-13463] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 08/21/2017] [Indexed: 11/19/2022]
Abstract
Presence of Cronobacter malonaticus in powdered infant formula (PIF) poses a high risk to infant and public health. Cronobacter malonaticus has been widely distributed in food and food processing environments, and the true origin of C. malonaticus in PIF is poorly understood. Control and prevention of C. malonaticus is necessary for achieving microbial safety of PIF. However, little information about decontamination of C. malonaticus is available. In this study, effects of hydrogen peroxide on inactivation and morphological changes of C. malonaticus cells were determined. Furthermore, inhibitory effects of H2O2 on biofilm formation in C. malonaticus were also performed. Results indicated that H2O2 could completely inactivate C. malonaticus in sterile water with 0.06% H2O2 for 25 min, 0.08% H2O2 for 15 min, and 0.10% for 10 min, respectively, whereas the survival rates of C. malonaticus in tryptic soy broth medium significantly increased with the same treatment time and concentration of H2O2. In addition, morphological changes of C. malonaticus cells, including cell shrinkage, disruption of cells, cell intercession, and leakage of intercellular material in sterile water after H2O2 treatment, were more predominant than those in tryptic soy broth. Finally, significant reduction in biofilm formation by H2O2 was found using crystal violet staining, scanning electron microscopy, and confocal laser scanning microscopy detection compared with control samples. This is the first report to determine the effects of H2O2 on C. malonaticus cells and biofilm formation. The findings provided valuable information for practical application of H2O2 for decontamination of C. malonaticus in dairy processing.
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Affiliation(s)
- Yingwang Ye
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
| | - Maofeng Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Rui Jiao
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Na Ling
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Xiyan Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Liaowang Tong
- School of Food Science and Engineering, Hefei University of Technology, Hefei 230009, China
| | - Haiyang Zeng
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Jumei Zhang
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
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Abstract
Cronobacter sakazakii and Cronobacter malonaticus are the most common species of Cronobacter , so it is necessary to detect the two species as soon as possible in surveillance programs. We developed a real-time PCR method for identifying C. sakazakii and C. malonaticus from the genus Cronobacter . In this study, the two pairs of primers and probes were designed, targeting 16S rRNA and fusA, respectively. The specificity of the real-time PCR assay was validated with 112 strains of Cronobacter , including 56 C. sakazakii , 32 C. malonaticus , 16 Cronobacter dublinensis , 6 Cronobacter turicensis , and 2 Cronobacter muytjensii . The results showed that C. sakazakii and C. malonaticus were all correctly identified, consistent with the results of another method by analyzing the clustering of the fusA sequence. The detection limit for pure culture was 102 CFU/ml and 103 CFU/g for artificially contaminated rehydrated powdered infant formula. Therefore, the developed real-time PCR was a rapid, sensitive, and reliable method for the identification of C. sakazakii and C. malonaticus .
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Affiliation(s)
- Xiaofang Li
- National Institute for Communicable Disease Control and Prevention and State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China.,Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education and School of Life Sciences, Jilin University, Changchun 130012, People's Republic of China
| | - Jinghua Cui
- National Institute for Communicable Disease Control and Prevention and State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China
| | - Xiaoli Du
- National Institute for Communicable Disease Control and Prevention and State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China
| | - Zhigang Cui
- National Institute for Communicable Disease Control and Prevention and State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China
| | - Yibing Huang
- Key Laboratory for Molecular Enzymology and Engineering of the Ministry of Education and School of Life Sciences, Jilin University, Changchun 130012, People's Republic of China
| | - Biao Kan
- National Institute for Communicable Disease Control and Prevention and State Key Laboratory for Infectious Disease Prevention and Control, Chinese Center for Disease Control and Prevention, Beijing 102206, People's Republic of China
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