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Song D, Jia A, Qi X, Dong K, Liu S, Man C, Yang X, Jiang Y. Co-culture of Cronobacter sakazakii and Staphylococcus aureus: Explore the influence of mixed biofilm formation and regulation of Cronobacter sakazakii biofilm formation genes. Food Res Int 2023; 173:113457. [PMID: 37803782 DOI: 10.1016/j.foodres.2023.113457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/01/2023] [Accepted: 09/10/2023] [Indexed: 10/08/2023]
Abstract
Bacterial biofilm is a protective matrix composed of metabolites secreted by bacteria that envelop bacteria. By forming a biofilm, bacteria can considerably improve their environmental tolerance. In food-related processing environment, different types of microorganisms are often present in biofilms. The main contaminating strain in the powdered infant formula (PIF) processing environment, Cronobacter sakazakii and Staphylococcus aureus continues to pollute the PIF processing environment after biofilm production. This study selected Cronobacter sakazakii with a weak biofilm-forming ability as one of the test organisms. The coexistence of Cronobacter sakazakii and Staphylococcus aureus on the surface of production equipment was simulated to analyze the interaction. Biofilm formation in the co-culture group was significantly higher than the others. In-depth study of the effect of Staphylococcus aureus on the biofilm formation genes of Cronobacter sakazakii. Results show two bacteria can coexist on the surface of a metal device, forming a more compact hybrid biofilm structure. Under co-culture conditions, S. aureus increased bcsA and fliD expression in Cronobacter sakazakii, whereas decreased bcsC expression. Signaling molecules produced by Staphylococcus aureus (Autoinducer 2) significantly promoted the biofilm formation of Cronobacter sakazakii at the concentration of 0-500 ng/mL (0.099-0.177) and up-regulated the expression of bcsA, filD and flhD genes.
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Affiliation(s)
- Danliangmin Song
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Ai Jia
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Xuehe Qi
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Kai Dong
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Shiyu Liu
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Harbin 150030, China.
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Harbin 150030, China.
| | - Yujun Jiang
- Department of Food Science, Northeast Agricultural University, Harbin 150038, China.
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2
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Chauhan R, Tall BD, Gopinath G, Azmi W, Goel G. Environmental risk factors associated with the survival, persistence, and thermal tolerance of Cronobacter sakazakii during the manufacture of powdered infant formula. Crit Rev Food Sci Nutr 2023; 63:12224-12239. [PMID: 35838158 DOI: 10.1080/10408398.2022.2099809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Cronobacter sakazakii is an opportunistic foodborne pathogen of concern for foods having low water activity such as powdered infant formula (PIF). Its survival under desiccated stress can be attributed to its ability to adapt effectively to many different environmental stresses. Due to the high risk to neonates and its sporadic outbreaks in PIF, C. sakazakii received great attention among the scientific community, food industry and health care providers. There are many extrinsic and intrinsic factors that affect C. sakazakii survival in low-moisture foods. Moreover, short- or long-term pre-exposure to sub-lethal physiological stresses which are commonly encountered in food processing environments are reported to affect the thermal resistance of C. sakazakii. Additionally, acclimation to these stresses may render C. sakazakii resistance to antibiotics and other antimicrobial agents. This article reviews the factors and the strategies responsible for the survival and persistence of C. sakazakii in PIF. Particularly, studies focused on the influence of various factors on thermal resistance, antibiotic or antimicrobial resistance, virulence potential and stress-associated gene expression are reviewed.
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Affiliation(s)
- Rajni Chauhan
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
| | | | - Gopal Gopinath
- Center for Food Safety and Applied Nutrition, U. S. Food and Drug Administration, Laurel, MD, USA
| | - Wamik Azmi
- Department of Biotechnology, Himachal Pradesh University, Shimla, India
| | - Gunjan Goel
- Department of Microbiology, School of Interdisciplinary and Applied Sciences, Central University of Haryana, Mahindra, India
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3
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Han A, Lee SY. An overview of various methods for in vitro biofilm formation: a review. Food Sci Biotechnol 2023; 32:1617-1629. [PMID: 37780598 PMCID: PMC10533769 DOI: 10.1007/s10068-023-01425-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 07/25/2023] [Accepted: 08/24/2023] [Indexed: 10/03/2023] Open
Abstract
Biofilms are widely present in the natural environment and are difficult to remove as they are a survival strategy of microorganisms. Thus, the importance of studying biofilms is being increasingly recognized in food, medical, dental, and water quality-related industries. While research on biofilm detection methods is actively progressing, research on biofilm formation is not progressing rapidly. Moreover, there are few standardized methods because biofilm formation is affected by various factors. However, comprehensive knowledge of biofilm formation is essential to select a suitable method for research purposes. To better understand the various in vitro biofilm formation methods, the principles and characteristics of each method are explained in this review by dividing the methods into static and dynamic systems. In addition, the applications of biofilm research based on various assays are also discussed.
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Affiliation(s)
- Areum Han
- Department of Food and Nutrition, Chung-Ang University, 4726 Seodong-dearo, Anseong-si, Gyeonggi-do 17546 Republic of Korea
| | - Sun-Young Lee
- Department of Food and Nutrition, Chung-Ang University, 4726 Seodong-dearo, Anseong-si, Gyeonggi-do 17546 Republic of Korea
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Factors Influencing Biofilm Formation by Salmonella enterica sv. Typhimurium, E. cloacae, E. hormaechei, Pantoea spp., and Bacillus spp. Isolated from Human Milk Determined by PCA Analysis. Foods 2022; 11:foods11233862. [PMID: 36496670 PMCID: PMC9738827 DOI: 10.3390/foods11233862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 12/05/2022] Open
Abstract
Bacteria enter milk during poor hygiene practices and can form a biofilm on surfaces that come into contact with human milk. The presence of a biofilm increases the risk of infections among newborns as bacteria protected by biofilm are resistant to washing and disinfection processes. The formation of the biofilm depends on the microbial species, environmental conditions, and the specific materials colonized. The aim of this study is to analyze the effects of factors such as temperature, incubation time, and initial cell concentration on biofilm formation by pathogenic bacteria isolated from human milk on model hydrophobic polystyrene surfaces. Model studies confirm that pathogenic bacteria appearing in human milk as a result of cross-contamination tend to form a biofilm. The majority of isolates formed biofilm at both 25 and 37 °C after 12 h at 1 × 103 CFU/mL inoculum count. Multivariate principal component analysis (PCA) showed that at lower temperatures, biofilm formation by bacterial isolates was the main determinant of biofilm formation, other factors were less important; however, at 37 °C, time was a factor in biofilm formation. The model research performed underlines the importance of maintaining the proper hygiene of rooms, surfaces, and devices for expressing, storing, and preparing mothers' milk and powdered infant formula (PIF) in facilities responsible for feeding newborns and premature babies.
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Xie L, Xie J, Chen X, Tao X, Xie J, Shi X, Huang Z. Comparative transcriptome analysis of Monascus purpureus at different fermentation times revealed candidate genes involved in exopolysaccharide biosynthesis. Food Res Int 2022; 160:111700. [DOI: 10.1016/j.foodres.2022.111700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/27/2022] [Accepted: 07/15/2022] [Indexed: 11/26/2022]
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6
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Wang S, Liu S, Hao G, Zhao L, Lü X, Wang H, Wang L, Zhang J, Ge W. Antimicrobial activity and mechanism of isothiocyanate from Moringa oleifera seeds against Bacillus cereus and Cronobacter sakazakii and its application in goat milk. Food Control 2022. [DOI: 10.1016/j.foodcont.2022.109067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Cao Y, Li L, Zhang Y, Liu F, Xiao X, Li X, Yu Y. Evaluation of Cronobacter sakazakii biofilm formation after sdiA knockout in different osmotic pressure conditions. Food Res Int 2022; 151:110886. [PMID: 34980413 DOI: 10.1016/j.foodres.2021.110886] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/23/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022]
Abstract
This study characterizes the impact of sdiA on biofilm formation under normal or osmotic stress conditions in Cronobacter sakazakii by constructing a sdiA deletion mutant (ΔsdiA). Here, the downregulation of flagellar assembly-related genes and upregulation of capsular, cellulose and lipopolysaccharide biosynthesis-associated genes in ΔsdiA were observed when compared to the wild type strain (WT) through transcriptomic analysis. Meanwhile, reduced ability of motility, enhanced cell surface hydrophobicity and stronger biofilms with extracellular matrix were observed in WT with deletion of sdiA. Both WT and ΔsdiA formed more biofilm in low osmotic stress medium, while in hyperosmolarity conditions, formation of biofilm was dramatically reduced. Our findings supported that sdiA might suppress biofilm formation of C. sakazakii by regulating biosynthesis of flagellar and extracellular polymeric substances. This study investigates the role of sdiA on biofilm formation in C. sakazakii, and provides the basis for the inhibition of C. sakazakii in food industry and infant-feeding.
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Affiliation(s)
- Yifang Cao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Li Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yan Zhang
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Fengsong Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Xinglong Xiao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
| | - Xiaofeng Li
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China
| | - Yigang Yu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province 510640, China.
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Kong X, Li C, Sun X, Niu B, Guo D, Jiang Y, Yang J, Chen Q. The maltose transporter subunit IICB of the phosphotransferase system: An important factor for biofilm formation of Cronobacter. Int J Food Microbiol 2021; 370:109517. [DOI: 10.1016/j.ijfoodmicro.2021.109517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 12/08/2021] [Accepted: 12/21/2021] [Indexed: 11/26/2022]
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9
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Ling N, Ou D, Shen Y, Zhang D, Wang Y, Tong L, Ding Y, Wang J, Yang X, Zhang J, Wu Q, Ye Y. Proteomics analysis mediated by quorum sensing luxS involved in oxidative stress in Cronobacter malonaticus. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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10
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Parra-Flores J, Holý O, Riffo F, Lepuschitz S, Maury-Sintjago E, Rodríguez-Fernández A, Cruz-Córdova A, Xicohtencatl-Cortes J, Mancilla-Rojano J, Troncoso M, Figueroa G, Ruppitsch W, Forsythe S. Profiling the Virulence and Antibiotic Resistance Genes of Cronobacter sakazakii Strains Isolated From Powdered and Dairy Formulas by Whole-Genome Sequencing. Front Microbiol 2021; 12:694922. [PMID: 34276629 PMCID: PMC8278472 DOI: 10.3389/fmicb.2021.694922] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/03/2021] [Indexed: 11/13/2022] Open
Abstract
Cronobacter sakazakii is an enteropathogen that causes neonatal meningitis, septicemia, and necrotizing enterocolitis in preterm infants and newborns with a mortality rate of 15 to 80%. Powdered and dairy formulas (P-DF) have been implicated as major transmission vehicles and subsequently the presence of this pathogen in P-DF led to product recalls in Chile in 2017. The objective of this study was to use whole genome sequencing (WGS) and laboratory studies to characterize Cronobacter strains from the contaminated products. Seven strains were identified as C. sakazakii, and the remaining strain was Franconibacter helveticus. All C. sakazakii strains adhered to a neuroblastoma cell line, and 31 virulence genes were predicted by WGS. The antibiograms varied between strains. and included mcr-9.1 and bla CSA genes, conferring resistance to colistin and cephalothin, respectively. The C. sakazakii strains encoded I-E and I-F CRISPR-Cas systems, and carried IncFII(pECLA), Col440I, and Col(pHHAD28) plasmids. In summary, WGS enabled the identification of C. sakazakii strains and revealed multiple antibiotic resistance and virulence genes. These findings support the decision to recall the contaminated powdered and dairy formulas from the Chilean market in 2017.
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Affiliation(s)
- Julio Parra-Flores
- Department of Nutrition and Public Health, Universidad del Bío-Bío, Chillán, Chile
| | - Ondrej Holý
- Department of Public Health, Palacký University Olomouc, Olomouc, Czechia
| | | | - Sarah Lepuschitz
- 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, Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Miriam Troncoso
- Microbiology and Probiotics Laboratory, Institute of Nutrition and Food Technology, Universidad de Chile, Santiago, Chile
| | - Guillermo Figueroa
- Microbiology and Probiotics Laboratory, Institute of Nutrition and Food Technology, Universidad de Chile, Santiago, Chile
| | - Werner Ruppitsch
- Austrian Agency for Health and Food Safety, Institute for Medical Microbiology and Hygiene, Vienna, Austria
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11
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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] [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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12
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Li C, Sun X, Niu B, Jiang Y, Yang J, Chen Q. Exopolysaccharide related gene bcsG affects biofilm formation of Cronobacter spp. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2020.104844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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13
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The role of the general stress response regulator RpoS in Cronobacter sakazakii biofilm formation. Food Res Int 2020; 136:109508. [DOI: 10.1016/j.foodres.2020.109508] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/25/2020] [Accepted: 06/28/2020] [Indexed: 11/20/2022]
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Lianou A, Nychas GJE, Koutsoumanis KP. Strain variability in biofilm formation: A food safety and quality perspective. Food Res Int 2020; 137:109424. [PMID: 33233106 DOI: 10.1016/j.foodres.2020.109424] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/02/2020] [Accepted: 06/05/2020] [Indexed: 12/20/2022]
Abstract
The inherent differences in microbial behavior among identically treated strains of the same microbial species, referred to as "strain variability", are regarded as an important source of variability in microbiological studies. Biofilms are defined as the structured multicellular communities with complex architecture that enable microorganisms to grow adhered to abiotic or living surfaces and constitute a fundamental aspect of microbial ecology. The research studies assessing the strain variability in biofilm formation are relatively few compared to the ones evaluating other aspects of microbial behavior such as virulence, growth and stress resistance. Among the available research data on intra-species variability in biofilm formation, compiled and discussed in the present review, most of them refer to foodborne pathogens as compared to spoilage microorganisms. Molecular and physiological aspects of biofilm formation potentially related to strain-specific responses, as well as information on the characterization and quantitative description of this type of biological variability are presented and discussed. Despite the considerable amount of available information on the strain variability in biofilm formation, there are certain data gaps and still-existing challenges that future research should cover and address. Current and future advances in systems biology and omics technologies are expected to aid significantly in the explanation of phenotypic strain variability, including biofilm formation variability, allowing for its integration in microbiological risk assessment.
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Affiliation(s)
- Alexandra Lianou
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food and Nutritional Sciences, Agricultural University of Athens, Athens 11855, Greece
| | - George-John E Nychas
- Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food and Nutritional Sciences, Agricultural University of Athens, Athens 11855, Greece
| | - Konstantinos P Koutsoumanis
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
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Capita R, Vicente-Velasco M, Rodríguez-Melcón C, García-Fernández C, Carballo J, Alonso-Calleja C. Effect of low doses of biocides on the antimicrobial resistance and the biofilms of Cronobacter sakazakii and Yersinia enterocolitica. Sci Rep 2019; 9:15905. [PMID: 31685860 PMCID: PMC6828698 DOI: 10.1038/s41598-019-51907-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 10/10/2019] [Indexed: 12/30/2022] Open
Abstract
The susceptibility of Cronobacter sakazakii ATCC 29544 (CS) and Yersinia enterocolitica ATCC 9610 (YE) to sodium hypochlorite (10% of active chlorine; SHY), peracetic acid (39% solution of peracetic acid in acetic acid; PAA) and benzalkonium chloride (BZK) was tested. Minimum inhibitory concentration (MIC) values (planktonic cells; microdilution broth method) of 3,800 ppm (SHY), 1,200 ppm (PAA) and 15 ppm (BZK) for CS, and 2,500 ppm (SHY), 1,275 ppm (PAA) and 20 ppm (BZK) for YE, were found. In some instances, an increase in growth rate was observed in presence of sub-MICs (0.25MIC, 0.50MIC or 0.75MIC) of biocides relative to the samples without biocides. The cultures exhibited an acquired tolerance to biocides and an increase in antibiotic resistance after exposure to sub-MICs of such disinfectants. Strains were able to form strong biofilms on polystyrene after 48 hours (confocal laser scanning microscopy), with average biovolumes in the observation field (14,161 µm2) of 242,201.0 ± 86,570.9 µm3 (CS) and 190,184.5 ± 40,860.3 µm3 (YE). Treatment of biofilms for 10 minutes with disinfectants at 1MIC or 2MIC reduced the biovolume of live cells. PAA (YE) and BZK (CS and YE) at 1MIC did not alter the percentage of dead cells relative to non-exposed biofilms, and their effect of countering biofilm was due principally to the detachment of cells. These results suggest that doses of PAA and BZK close to MICs might lead to the dissemination of live bacteria from biofilms with consequent hazards for public health.
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Affiliation(s)
- Rosa Capita
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain
- Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - María Vicente-Velasco
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain
- Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - Cristina Rodríguez-Melcón
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain
- Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - Camino García-Fernández
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain
- Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - Javier Carballo
- Area of Food Technology, University of Vigo, E-32004, Ourense, Spain
| | - Carlos Alonso-Calleja
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain.
- Institute of Food Science and Technology, University of León, E-24071, León, Spain.
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Aly MA, Domig KJ, Kneifel W, Reimhult E. Whole Genome Sequencing-Based Comparison of Food Isolates of Cronobacter sakazakii. Front Microbiol 2019; 10:1464. [PMID: 31333604 PMCID: PMC6615433 DOI: 10.3389/fmicb.2019.01464] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 06/11/2019] [Indexed: 12/13/2022] Open
Abstract
Cronobacter sakazakii is an emerging foodborne pathogen, which is linked to life-threatening infections causing septicemia, meningitis, and necrotizing enterocolitis. These infections have been epidemiologically connected to ingestion of contaminated reconstituted powder infant formula. Even at low water activity C. sakazakii can survive for a long time; it is capable of protective biofilm formation and occasionally shows high virulence and pathogenicity even following stressful environmental conditions. Hence it is a challenging task for the food industry to control contamination of food ingredients and products through the entire production chain, since an increasing number of severe food-related outbreaks of C. sakazakii infections has been observed. The seemingly great capability of C. sakazakii to survive even strict countermeasures combined with its prevalence in many food ingredients requires a greater in depth understanding of its virulence factors to master the food safety issues related to this organism. In this context, we present the whole genome sequence (WGS) of two different C. sakazakii isolated from skimmed milk powder (C7) and ready-to-eat salad mix (C8), respectively. These are compared to other, already sequenced, C. sakazakii genomes. Sequencing of the fusA allele revealed that both isolates were C. sakazakii. We investigated the molecular characteristics of both isolates relevant for genes associated with pathogenesis and virulence factors, resistance to stressful environmental conditions (e.g., osmotic and heat), survival in desiccation as well as conducted a comparative genomic analysis. By using multi-locus sequence typing (MLST), the genetic type of both isolates is assessed and the number of unique genes is determined. DNA of C. sakazakii C8 is shown to hold a novel and unique sequence type; the number of unique genes identified in the genomic sequence of C. sakazakii C7 and C8 were 109 and 188, respectively. Some of the determined unique genes such as the rhs and VgrG genes are linked to the Type VI Secretion System cluster, which is associated with pathogenicity and virulence factors. Moreover, seven genes encoding for multi-drug resistance were found in both isolates. The finding of a number of genes linked to producing capsules and biofilm are likely related to the observed resistance to desiccation.
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Affiliation(s)
- Mohamed A Aly
- Department of Nanobiotechnology, Institute for Biologically Inspired Materials, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.,Department of Food Science, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
| | - Konrad J Domig
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Wolfgang Kneifel
- Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Erik Reimhult
- Department of Nanobiotechnology, Institute for Biologically Inspired Materials, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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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] [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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18
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Aly MA, Reimhult E, Kneifel W, Domig KJ. Characterization of Biofilm Formation by Cronobacter spp. Isolates of Different Food Origin under Model Conditions. J Food Prot 2019; 82:65-77. [PMID: 30702944 DOI: 10.4315/0362-028x.jfp-18-036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cronobacter spp. are opportunistic human pathogens that cause serious diseases in neonates and immunocompromised people. Owing to their biofilm formation on various surfaces, both their detection and their removal from production plants constitute a major challenge. In this study, food samples were randomly collected in Austria and examined for the presence of Cronobacter spp. Presumptive isolates were identified by a polyphasic approach. Five percent of the samples were positive for C. sakazakii and 2.4% for C. dublinensis. Individual growth of the isolates was characterized based on lag time, growth rate, and generation time. During an incubation period of 6 to 72 h, biofilm formation of 11 selected isolates was quantified under model conditions by a crystal violet staining assay with 96-well plates with different carbon sources (lactose, glucose, maltose, sucrose, and sodium acetate) and NaCl levels and under variable temperature and pH conditions. Biofilm formation was more pronounced at lactose concentrations between 0.25 and 3% compared with 5% lactose, which lead to thinner layers. C. sakazakii isolate C7, isolated from infant milk powder, was the strongest biofilm producer at 10 mM Mg2+ and 5 mM Mn2+, 0.5% sodium acetate, at pH levels between 7 and 9 at 37°C for 24 h. C. sakazakii strain C6 isolated from a plant air filter was identified as a moderate biofilm former and C. sakazakii strain DSM 4485, a clinical isolate, as a weak biofilm former. Based on PCR detection, genes bcsA, bcsB, and bcsG encoding for cellulose could be identified as markers for biofilm formation. Isolates carrying bcsA and bcsB showed significantly stronger biofilm formation than isolates without these genes ( P < 0.05), in strong correlation with the results obtained in the crystal violet assay. Further investigations using confocal laser scanning microscopy revealed that extracellular polymeric substances and glycocalyx secretions were the dominating components of the biofilms and that the viable fraction of bacteria in the biofilm decreased over time.
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Affiliation(s)
- Mohamed A Aly
- 1 Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria.,2 Department of Food Science, Faculty of Agriculture, Ain Shams University, Cairo, Egypt.,3 Department of Nanobiotechnology, Institute for Biologically Inspired Materials, BOKU - University of Natural Resources and Life Sciences, A-1190 Vienna, Austria (ORCID: http://orcid.org/0000-0003-1090-4284 [K.J.D.])
| | - Erik Reimhult
- 3 Department of Nanobiotechnology, Institute for Biologically Inspired Materials, BOKU - University of Natural Resources and Life Sciences, A-1190 Vienna, Austria (ORCID: http://orcid.org/0000-0003-1090-4284 [K.J.D.])
| | - Wolfgang Kneifel
- 1 Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria
| | - Konrad J Domig
- 1 Department of Food Science and Technology, Institute of Food Science, University of Natural Resources and Life Sciences, A-1190 Vienna, Austria
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19
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Tong L, Jiao R, Zhang X, Ou D, Wang Y, Zhang J, Wu Q, Ye Y. Inhibitory effects of chitosan on Cronobacter malonaticus cells and biofilm formation. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.07.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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20
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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] [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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21
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Ponomareva AL, Buzoleva LS, Bogatyrenko EA. Abiotic Environmental Factors Affecting the Formation of Microbial Biofilms. BIOL BULL+ 2018. [DOI: 10.1134/s106235901805014x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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22
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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] [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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23
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Ling N, Zhang J, Li C, Zeng H, He W, Ye Y, Wu Q. The Glutaredoxin Gene, grxB, Affects Acid Tolerance, Surface Hydrophobicity, Auto-Aggregation, and Biofilm Formation in Cronobacter sakazakii. Front Microbiol 2018; 9:133. [PMID: 29459854 PMCID: PMC5807413 DOI: 10.3389/fmicb.2018.00133] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2017] [Accepted: 01/19/2018] [Indexed: 12/22/2022] Open
Abstract
Cronobacter species are foodborne pathogens that can cause neonatal meningitis, necrotizing enterocolitis, and sepsis; they have unusual abilities to survive in environmental stresses such as acid stress. However, the factors involved in acid stress responses and biofilm formation in Cronobacter species are poorly understood. In this study, we investigated the role of grxB on cellular morphology, acid tolerance, surface hydrophobicity, auto-aggregation (AAg), motility, and biofilm formation in Cronobacter sakazakii. The deletion of grxB decreased resistance to acid stresses, and notably led to weaker surface hydrophobicity, AAg, and biofilm formation under normal and acid stress conditions, compared with those of the wild type strain; however, motility was unaffected. Therefore, grxB appears to contribute to the survival of C. sakazakii in acid stresses and biofilm formation. This is the first report to provide valuable evidence for the role of grxB in acid stress responses and biofilm formation in C. sakazakii.
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Affiliation(s)
- Na Ling
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China.,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 Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Chengsi Li
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Haiyan Zeng
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Wenjing He
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
| | - Yingwang Ye
- School of Food Science and 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 Open Laboratory of Applied Microbiology, Guangdong Institute of Microbiology, Guangzhou, China
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24
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Gupta TB, Mowat E, Brightwell G, Flint SH. Biofilm formation and genetic characterization of New Zealand Cronobacter
isolates. J Food Saf 2017. [DOI: 10.1111/jfs.12430] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Tanushree B. Gupta
- Hopkirk Research Institute; Food and Bio-Based Products, AgResearch Limited; Palmerston North New Zealand
| | - Eilidh Mowat
- Plant Physiology Team, Hill Laboratories; Hamilton New Zealand
| | - Gale Brightwell
- Hopkirk Research Institute; Food and Bio-Based Products, AgResearch Limited; Palmerston North New Zealand
| | - Steve H. Flint
- Massey Institute of Food Science and Technology, Massey University; Palmerston North New Zealand
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25
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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] [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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Yu S, Yan L, Wu X, Li F, Wang D, Xu H. Multiplex PCR coupled with propidium monoazide for the detection of viable Cronobacter sakazakii, Bacillus cereus, and Salmonella spp. in milk and milk products. J Dairy Sci 2017; 100:7874-7882. [DOI: 10.3168/jds.2017-13110] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 05/27/2017] [Indexed: 11/19/2022]
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27
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Molecular identification of potential denitrifying bacteria and use of D-optimal mixture experimental design for the optimization of denitrification process. Microb Pathog 2016; 93:158-65. [DOI: 10.1016/j.micpath.2016.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2015] [Revised: 01/20/2016] [Accepted: 02/11/2016] [Indexed: 11/22/2022]
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