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Quan H, Gong X, Chen Q, Zheng F, Yu Y, Liu D, Wang W, Chu Y. Functional Characterization of a Novel SMR-Type Efflux Pump RanQ, Mediating Quaternary Ammonium Compound Resistance in Riemerella anatipestifer. Microorganisms 2023; 11:microorganisms11040907. [PMID: 37110330 PMCID: PMC10142375 DOI: 10.3390/microorganisms11040907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Riemerella anatipestifer (R. anatipestifer) is a multidrug-resistant bacterium and an important pathogen responsible for major economic losses in the duck industry. Our previous study revealed that the efflux pump is an important resistance mechanism of R. anatipestifer. Bioinformatics analysis indicated that the GE296_RS02355 gene (denoted here as RanQ), a putative small multidrug resistance (SMR)-type efflux pump, is highly conserved in R. anatipestifer strains and important for the multidrug resistance. In the present study, we characterized the GE296_RS02355 gene in R. anatipestifer strain LZ-01. First, the deletion strain RA-LZ01ΔGE296_RS02355 and complemented strain RA-LZ01cΔGE296_RS02355 were constructed. When compared with that of the wild-type (WT) strain RA-LZ01, the mutant strain ΔRanQ showed no significant influence on bacterial growth, virulence, invasion and adhesion, morphology biofilm formation ability, and glucose metabolism. In addition, the ΔRanQ mutant strain did not alter the drug resistance phenotype of the WT strain RA-LZ01 and displayed enhanced sensitivity toward structurally related quaternary ammonium compounds, such as benzalkonium chloride and methyl viologen, which show high efflux specificity and selectivity. This study may help elucidate the unprecedented biological functions of the SMR-type efflux pump in R. anatipestifer. Thus, if this determinant is horizontally transferred, it could cause the spread of quaternary ammonium compound resistance among bacterial species.
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Affiliation(s)
- Heng Quan
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Xiaowei Gong
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Qiwei Chen
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
- Correspondence: (Q.C.); (W.W.)
| | - Fuying Zheng
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Yongfeng Yu
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Donghui Liu
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
| | - Wenhui Wang
- College of Veterinary Medicine, Gansu Agricultural University, Lanzhou 730070, China
- Correspondence: (Q.C.); (W.W.)
| | - Yuefeng Chu
- State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730000, China
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Ling N, Zhang X, Forsythe S, Zhang D, Shen Y, Zhang J, Ding Y, Wang J, Wu Q, Ye Y. Bacteroides fragilis ameliorates Cronobacter malonaticus lipopolysaccharide-induced pathological injury through modulation of the intestinal microbiota. Front Immunol 2022; 13:931871. [PMID: 36211338 PMCID: PMC9536467 DOI: 10.3389/fimmu.2022.931871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/08/2022] [Indexed: 11/23/2022] Open
Abstract
Cronobacter has attracted considerable attention due to its association with meningitis and necrotizing enterocolitis (NEC) in newborns. Generally, lipopolysaccharide (LPS) facilitates bacterial translocation along with inflammatory responses as an endotoxin; however, the pathogenicity of Cronobacter LPS and the strategies to alleviate the toxicity were largely unknown. In this study, inflammatory responses were stimulated by intraperitoneal injection of Cronobacter malonaticus LPS into Sprague–Dawley young rats. Simultaneously, Bacteroides fragilis NCTC9343 were continuously fed through gavage for 5 days before or after injection of C. malonaticus LPS to evaluate the intervention effect of B. fragilis. We first checked the morphological changes of the ileum and colon and the intestinal microbiota and then detected the generation of inflammatory factors, including tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) and the expression of Toll-like receptor 4 (TLR4), occludin, claudin-4, and iNOs. The results indicated that C. malonaticus LPS exacerbated intestinal infection by altering gut microbe profile, tight junction protein expression, and releasing inflammatory factors in a time- and dose-dependent manner. Intriguingly, treatment with B. fragilis obviously diminished the pathological injuries and expression of TLR4 caused by C. malonaticus LPS while increasing gut microbes like Prevotella-9. We note that Shigella, Peptoclostridium, and Sutterella might be positively related to C. malonaticus LPS infection, but Prevotella-9 was negatively correlated. The results suggested that the intestinal microbiota is an important target for the prevention and treatment of pathogenic injuries induced by C. malonaticus LPS.
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Affiliation(s)
- Na Ling
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Xiyan Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | | | - Danfeng Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Yizhong Shen
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
| | - Jumei Zhang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Yu Ding
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Juan Wang
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
- *Correspondence: Yingwang Ye, ; Qingping Wu,
| | - Yingwang Ye
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, China
- Guangdong Provincial Key Laboratory of Microbial Safety and Health, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
- *Correspondence: Yingwang Ye, ; Qingping Wu,
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Zhang W, Zhou H, Jiang Y, He J, Yao Y, Wang J, Liu X, Leptihn S, Hua X, Yu Y. Acinetobacter baumannii Outer Membrane Protein A Induces Pulmonary Epithelial Barrier Dysfunction and Bacterial Translocation Through The TLR2/IQGAP1 Axis. Front Immunol 2022; 13:927955. [PMID: 35844614 PMCID: PMC9280087 DOI: 10.3389/fimmu.2022.927955] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/02/2022] [Indexed: 01/15/2023] Open
Abstract
Pulmonary epithelial barrier dysfunction is a critical pathophysiological process in pneumonia and associated invasive infections, such as those caused by Acinetobacter baumannii. However, the mechanisms underlying A. baumannii-induced pulmonary epithelial barrier dysfunction and bacterial translocation remain unclear. In this study, lungs of mice and A549 human epithelial cell monolayers were challenged with the A. baumannii wild-type strain and an outer membrane protein A (ompA) deletion strain. In addition, epithelial cells in culture were treated with purified OmpA protein or transfected with a eukaryotic expression vector encoding ompA (pCMV-ompA). Bacterial translocation across cell monolayers and intrapulmonary burden were measured, barrier function was evaluated in vivo and in vitro; cell migration ability was determined. The specific inhibitors C29 and JSH-23 were used to suppress the activity of Toll-like receptor 2 (TLR2) and of NF-κB, respectively. IQ-GTPase-activating protein 1 (IQGAP1) small interfering RNA was used to knock down endogenous IQGAP1 expression. In this work, we show that OmpA from A. baumannii increased the production of pro-inflammatory cytokines, remodeled the cytoskeleton, and internalized intercellular adherens junctions (AJs); these changes eventually induced pulmonary epithelial barrier dysfunction to promote bacterial translocation. IQGAP1-targeting small interfering RNA and chemical inhibition of TLR2 or NF-κB prevented high permeability of the pulmonary epithelial barrier. TLR2/NF-κB signaling was involved in OmpA-induced inflammation, IQGAP1-mediated OmpA-induced opening of the pulmonary epithelial barrier via cytoskeleton dynamic remodeling, and cellular redistribution of the major AJ protein, E-cadherin. These observations indicate that A. baumannii uses OmpA to overcome epithelial defences and cross the pulmonary epithelial barrier.
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Affiliation(s)
- Wang Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Hua Zhou
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yan Jiang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Jintao He
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yue Yao
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Jianfeng Wang
- Department of Respiratory and Critical Care Medicine, Zhejiang Provincial Hospital of Chinese Medicine, Hangzhou, China
| | - Xiaochen Liu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Sebastian Leptihn
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Zhejiang University-University of Edinburgh Institute, Zhejiang University, Haining, China
- University of Edinburgh Medical School, Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- *Correspondence: Yunsong Yu, ; Xiaoting Hua,
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
- *Correspondence: Yunsong Yu, ; Xiaoting Hua,
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Elkhawaga AA, Hetta HF, Osman NS, Hosni A, El-Mokhtar MA. Emergence of Cronobacter sakazakii in Cases of Neonatal Sepsis in Upper Egypt: First Report in North Africa. Front Microbiol 2020; 11:215. [PMID: 32210926 PMCID: PMC7075355 DOI: 10.3389/fmicb.2020.00215] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 01/30/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND AND AIM Cronobacter sakazakii (C. sakazakii) has attracted considerable attention as an emerging neonatal pathogen and has been associated with outbreaks of life-threatening septicemia, necrotizing enterocolitis, and meningitis in neonates and infants globally. No data about the role of C. sakazakii as a cause of neonatal sepsis in North Africa is availale. Herein, we aimed to study the incidence of C. sakazakii in cases of neonatal sepsis, its distribution in different food samples in Egypt, antimicrobial profile, and the ability of the strains to form biofilms. METHODS A total of 100 positive blood cultures from cases of neonatal sepsis admitted to the neonatal ICU at Assiut University Children's Hospital, Egypt, were analyzed. In addition, 1,100 food samples, including 400 powdered infant formula (PIF), 500 herbs, and 200 water samples were screened for the presence of C. sakazakii. We evaluated the antimicrobial profile and the ability of the strains to form biofilms. RESULTS Cronobacter sakazakii was detected in 12 out of 100 cases of neonatal sepsis. The organism was also isolated from PIF, herbs, and water in percentages of 17.5, 9.2, and 7.5%, respectively. Regarding the antimicrobial sensitivity, all strains were resistant to ampicillin, amoxicillin, ampicillin/sulbactam, clindamycin, cephalothin, and cephalexin. In addition, C. sakazakii strains showed the ability to form biofilms, but with variable degrees of cell density. CONCLUSION We reported, for the first time, cases of neonatal sepsis caused by the emerging life-threatening pathogen C. sakazakii in Egypt. The organism was also detected in contaminated PIF, herbs, and water, which may be sources of infection for neonates, especially in countries where natural herbs are widely used as an alternative medicine. Finally, collective efforts by the parents, manufacturers of PIF, and healthcare personnel are essential to prevent serious infections caused by C. sakazakii, particularly in infants.
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Affiliation(s)
- Amal A. Elkhawaga
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Helal F. Hetta
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
- Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Naglaa S. Osman
- Department of Pediatrics, Children’s Hospital, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Amal Hosni
- Department of Clinical Pathology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Mohamed A. El-Mokhtar
- Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, Egypt
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Cui J, Hu J, Du X, Yan C, Xue G, Li S, Cui Z, Huang H, Yuan J. Genomic Analysis of Putative Virulence Factors Affecting Cytotoxicity of Cronobacter. Front Microbiol 2020; 10:3104. [PMID: 32117082 PMCID: PMC7019382 DOI: 10.3389/fmicb.2019.03104] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Accepted: 12/23/2019] [Indexed: 01/07/2023] Open
Abstract
Cronobacter spp. can cause systemic infections, such as meningitis, sepsis, and necrotizing enterocolitis, in immunocompromised patients, especially neonates. Although some virulence factors have been reported previously, the pathogenesis of Cronobacter remains unclear. In this study, we compared genome sequences from different Cronobacter species, sequence types, and sources, with the virulence genes in the virulence factor database. The results showed that Cronobacter has species specificity for these virulence genes. Additionally, two gene clusters, including sfp encoding fimbriae and hly encoding hemolysin, were discovered. Through cell adhesion, cytotoxicity, and hemolysis assays, we found that the isolates possessing the two gene clusters had higher cytotoxicity and stronger hemolysis capacity than those of other isolates in this study. Moreover, analysis of type VI secretion system (T6SS) cluster and putative fimbria gene clusters of Cronobacter revealed that T6SS have species specificity and isolates with high cytotoxicity possessed more complete T6SS cluster construction than that of the rest. In conclusion, the two novel gene clusters and T6SS cluster were involved in the mechanism underlying the cytotoxicity of Cronobacter.
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Affiliation(s)
- Jinghua Cui
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China.,State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jinrui Hu
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiaoli Du
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Chao Yan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Guanhua Xue
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Shaoli Li
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
| | - Zhigang Cui
- State Key Laboratory of Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Disease, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Hua Huang
- Beijing Products Quality Supervision and Inspection Institute, Beijing, China
| | - Jing Yuan
- Department of Bacteriology, Capital Institute of Pediatrics, Beijing, China
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Athinuwat D, Brooks S. The OmpA Gene of Xanthomonas axonopodis pv. glycines is Involved in Pathogenesis of Pustule Disease on Soybean. Curr Microbiol 2019; 76:879-887. [PMID: 31089795 DOI: 10.1007/s00284-019-01702-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 05/06/2019] [Indexed: 10/26/2022]
Abstract
The goal of this study was to elucidate the role of the outer membrane protein A (ompA) gene of Xanthomonas axonopodis pv. glycines in bacterial pustule pathogenesis of soybean. An ompA mutant of X. axonopodis pv. glycines KU-P-SW005 was shown to significantly decrease cellulase, pectate lyase, and polysaccharide production. The production of these proteins in the ompA mutant was approximately five times lower than that of the wildtype. The ompA mutant also exhibited modified biofilm development. More importantly, the mutant reduced disease severity to the soybean. Ten days after inoculation, the virulence rating of the susceptible soybean cv. SJ4 inoculated with the ompA mutant was 11.23%, compared with 87.98% for the complemented ompA mutant. Production of cellulase, pectate lyase, polysaccharide was restored, biofilm, and pustule numbers were restored in the complemented ompA mutant that did not differ from the wild type. Taken together, these data suggest that OmpA-mediated invasion plays an important role in protein secretion during pathogenesis to soybean.
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Affiliation(s)
- Dusit Athinuwat
- Department of Agricultural Technology, Faculty of Science and Technology, Thammasat University, Pathumthani, Thailand.
| | - Siraprapa Brooks
- School of Science, Mae Fah Luang University, Chaing Rai, 57100, Thailand
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Occurrence of virulence factors in Cronobacter sakazakii and Cronobacter malonaticus originated from clinical samples. Microb Pathog 2018; 127:250-256. [PMID: 30550840 DOI: 10.1016/j.micpath.2018.12.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [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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Alsonosi AM, Holy O, Forsythe SJ. Characterization of the pathogenicity of clinical Cronobacter malonaticus strains based on the tissue culture investigations. Antonie van Leeuwenhoek 2018; 112:435-450. [DOI: 10.1007/s10482-018-1178-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 10/05/2018] [Indexed: 02/06/2023]
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Parra-Flores J, Aguirre J, Juneja V, Jackson EE, Cruz-Córdova A, Silva-Sanchez J, Forsythe S. Virulence and Antibiotic Resistance Profiles of Cronobacter sakazakii and Enterobacter spp. Involved in the Diarrheic Hemorrhagic Outbreak in Mexico. Front Microbiol 2018; 9:2206. [PMID: 30319560 PMCID: PMC6171480 DOI: 10.3389/fmicb.2018.02206] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/29/2018] [Indexed: 02/02/2023] Open
Abstract
Cronobacter spp. are bacterial pathogens that cause neonatal meningitis, septicemia, and necrotizing enterocolitis in infants with a lethality rate of 40–80%. Powdered infant formulas (PIF) have been implicated as the main vehicles of transmission. This pathogen can also cause infection through contaminated expressed breast milk, and it has been recovered from neonatal feeding tubes of neonates not fed reconstituted PIF and milk kitchen areas. This study analyzed antibiotic resistance profiles and the tissue virulence tests of Cronobacter sakazakii and Enterobacter spp. recovered from PIF, infant fecal matter‘s, and milk kitchen environment involved in a diarrheic hemorrhagic outbreak in 2011 in Mexico. The strains isolated from the outbreak had similar antibiotic resistance profiles and pathogenicity irrespective of isolation site, however, C. sakazakii strains isolated from PIF showed significantly higher invasive profiles than Enterobacter spp. (p = 0.001) and 83% were resistant to more than one antibiotic. The findings of this study can be used to complement existing information to better control Cronobacter and Enterobacter spp. contamination in PIF production, prevent its transmission, and improve infant food safety.
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Affiliation(s)
- Julio Parra-Flores
- Departamento de Nutrición y Salud Pública, Facultad Ciencias de la Salud y de los Alimentos, Universidad del Bío-Bío, Chillán, Chile
| | - Juan Aguirre
- Departamento Agroindustria y Enología, Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago, Chile
| | - Vijay Juneja
- Residue Chemistry and Predictive Microbiology Research Unit, Eastern Regional Research Center, Agricultural Research Service, United States Department of Agriculture (USDA), Wyndmoor, PA, United States
| | - Emily E Jackson
- Department of Biology, University of Nevada, Reno, Reno, NV, United States
| | - Ariadnna Cruz-Córdova
- Laboratorio de Bacteriología Intestinal, Hospital Infantil de México, Federico Gómez, Mexico City, Mexico
| | - Jesus Silva-Sanchez
- Grupo de Resistencia Bacteriana, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, Mexico
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Chaudhuri D, Roy Chowdhury A, Biswas B, Chakravortty D. Salmonella Typhimurium Infection Leads to Colonization of the Mouse Brain and Is Not Completely Cured With Antibiotics. Front Microbiol 2018; 9:1632. [PMID: 30072981 PMCID: PMC6058050 DOI: 10.3389/fmicb.2018.01632] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 06/29/2018] [Indexed: 11/13/2022] Open
Abstract
Salmonella systemic infections claim thousands of lives worldwide even today. Certain cases lead to an infection in the brain culminating in meningitis and associated neurological abnormalities. Multiple reports have indicated neurological manifestations in patients suffering from typhoid fever during the course of infection and afterwards. While the meanderings of Salmonella systemic infections are fairly well studied, the flow of events in the brain is very poorly understood. We investigated the colonization of various brain parts by Salmonella in mice. It was observed that the bacterium is frequently able to invade various brain parts in mice. Selected mutants namely deletion mutants of key proteins encoded by the Salmonella pathogenicity islands (SPIs) 1 and 2 and ompA gene were also used to decipher the roles of specific genes in establishing an infection in the brain. Our results suggest roles for the Salmonella pathogenicity island (SPI) 1 and outer membrane protein A gene in enabling blood-brain barrier penetration by the pathogen. We further investigated behavioral abnormalities in infected mice and used an antibiotic treatment regime in an attempt to reverse the same. Results show some mice still display behavioral abnormalities and a high bacterial burden in brain despite clearance from spleen and liver. Overall, our study provides novel insights into S. Typhimurium's capacity to invade the mouse brain and the effectiveness of antibiotic treatment on behavioral manifestations due to infection. These observations could have important implications in understanding reported neurological manifestations in typhoid patients.
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Affiliation(s)
- Debalina Chaudhuri
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Atish Roy Chowdhury
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Biswendu Biswas
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
| | - Dipshikha Chakravortty
- Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.,Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, India
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Jameelah M, Dewanti-Hariyadi R, Nurjanah S. Expression of rpoS, ompA and hfq genes of Cronobacter sakazakii strain Yrt2a during stress and viable but nonculturable state. Food Sci Biotechnol 2018; 27:915-920. [PMID: 30263819 PMCID: PMC6049694 DOI: 10.1007/s10068-018-0313-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/03/2018] [Accepted: 01/07/2018] [Indexed: 11/24/2022] Open
Abstract
Cronobacter spp. in powdered infant formula has been etiologically linked to meningitis and necrotizing enterocolitis in certain groups of infants. This study aimed to determine whether C. sakazakii Yrt2a strain experiencing desiccation stress could enter viable but nonculturable (VBNC) state as well as to examine the expression of genes associated with stress and virulence during the above states. Stress and VBNC conditions were determined based on viability and culturability assays. Expression of genes related to stress (rpoS) and virulence (hfq and ompA) was evaluated by real-time PCR. The results showed that C. sakazakii Yrt2a entered VBNC 24 days post exposure to 2 h of desiccation treatment. The expression of rpoS, hfq and ompA genes was up-regulated during stress conditions, suggesting that Cronobacter successfully managed stress to maintain its culturability while maintaining its virulence. The expression of the target genes decreased at VBNC state but remained higher than that of a normal state. These findings reinforce the assumption that C. sakazakii undergoing VBNC state maintains its pathogenicity.
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Affiliation(s)
- Maryam Jameelah
- Department of Food Science and Technology, Faculty of Agricultural Engineering and Technology, Bogor Agricultural University, IPB Dramaga, Bogor, 16680 Indonesia
| | - Ratih Dewanti-Hariyadi
- Department of Food Science and Technology, Faculty of Agricultural Engineering and Technology, Bogor Agricultural University, IPB Dramaga, Bogor, 16680 Indonesia
- Southeast Asian Food and Agricultural Science and Technology Center, Bogor Agricultural University, Jl. Puspa Lingkar Kampus IPB Dramaga, Bogor, 16680 Indonesia
| | - Siti Nurjanah
- Department of Food Science and Technology, Faculty of Agricultural Engineering and Technology, Bogor Agricultural University, IPB Dramaga, Bogor, 16680 Indonesia
- Southeast Asian Food and Agricultural Science and Technology Center, Bogor Agricultural University, Jl. Puspa Lingkar Kampus IPB Dramaga, Bogor, 16680 Indonesia
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Lehner A, Tall BD, Fanning S, Srikumar S. Cronobacter spp.—Opportunistic Foodborne Pathogens: an Update on Evolution, Osmotic Adaptation and Pathogenesis. CURRENT CLINICAL MICROBIOLOGY REPORTS 2018. [DOI: 10.1007/s40588-018-0089-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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14
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Fei P, Jiang Y, Jiang Y, Yuan X, Yang T, Chen J, Wang Z, Kang H, Forsythe SJ. Prevalence, Molecular Characterization, and Antibiotic Susceptibility of Cronobacter sakazakii Isolates from Powdered Infant Formula Collected from Chinese Retail Markets. Front Microbiol 2017; 8:2026. [PMID: 29089940 PMCID: PMC5651101 DOI: 10.3389/fmicb.2017.02026] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 10/04/2017] [Indexed: 11/13/2022] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen that causes severe infections in neonates and infants through contaminated powdered infant formula (PIF). Therefore, the aim of this study was a large-scale study on determine the prevalence, molecular characterization and antibiotic susceptibility of C. sakazakii isolates from PIF purchased from Chinese retail markets. Two thousand and twenty PIF samples were collected from different institutions. Fifty-six C. sakazakii strains were isolated, and identified using fusA sequencing analysis, giving a contamination rate of 2.8%. Multilocus sequence typing (MLST) was more discriminatory than other genotyping methods. The C. sakazakii isolates were divided into 14 sequence types (STs) by MLST, compared with only seven clusters by ompA and rpoB sequence analysis, and four C. sakazakii serotypes by PCR-based O-antigen serotyping. C. sakazakii ST4 (19/56, 33.9%), ST1 (12/56, 21.4%), and ST64 (11/56, 16.1%) were the dominant sequence types isolated. C. sakazakii serotype O2 (34/56, 60.7%) was the primary serotype, along with ompA6 and rpoB1 as the main allele profiles, respectively. Antibiotic susceptibility testing indicated that all C. sakazakii isolates were susceptible to ampicillin-sulbactam, cefotaxime, ciprofloxacin, meropenem, tetracycline, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole. The majority of C. sakazakii strains were susceptible to chloramphenicol and gentamicin (87.5 and 92.9%, respectively). In contrast, 55.4% C. sakazakii strains were resistant to cephalothin. In conclusion, this large-scale study revealed the prevalence and characteristics of C. sakazakii from PIF in Chinese retail markets, demonstrating a potential risk for neonates and infants, and provide a guided to effective control the contamination of C. sakazakii in production process.
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Affiliation(s)
- Peng Fei
- College of Food and Biological Engineering, Henan University of Science and Technology, Luoyang, China
| | - Yichao Jiang
- Changbai Mountains Food and Drug Inspection Testing Center, Baishan, China
| | - Yan Jiang
- Department of Market Supervision and Management, MuLing Food Inspection Testing Center, Mudanjiang, China
| | - Xiujuan Yuan
- Anda Department of Animal Husbandry and Veterinary, Anda, China
| | - Tongxiang Yang
- College of Food and Biological Engineering, Henan University of Science and Technology, Luoyang, China
| | - Junliang Chen
- College of Food and Biological Engineering, Henan University of Science and Technology, Luoyang, China
| | - Ziyuan Wang
- College of Food and Biological Engineering, Henan University of Science and Technology, Luoyang, China
| | - Huaibin Kang
- College of Food and Biological Engineering, Henan University of Science and Technology, Luoyang, China
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15
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Kothary MH, Gopinath GR, Gangiredla J, Rallabhandi PV, Harrison LM, Yan QQ, Chase HR, Lee B, Park E, Yoo Y, Chung T, Finkelstein SB, Negrete FJ, Patel IR, Carter L, Sathyamoorthy V, Fanning S, Tall BD. Analysis and Characterization of Proteins Associated with Outer Membrane Vesicles Secreted by Cronobacter spp. Front Microbiol 2017; 8:134. [PMID: 28232819 PMCID: PMC5299011 DOI: 10.3389/fmicb.2017.00134] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 01/19/2017] [Indexed: 02/02/2023] Open
Abstract
Little is known about secretion of outer membrane vesicles (OMVs) by Cronobacter. In this study, OMVs isolated from Cronobacter sakazakii, Cronobacter turicensis, and Cronobacter malonaticus were examined by electron microscopy (EM) and their associated outer membrane proteins (OMP) and genes were analyzed by SDS-PAGE, protein sequencing, BLAST, PCR, and DNA microarray. EM of stained cells revealed that the OMVs are secreted as pleomorphic micro-vesicles which cascade from the cell's surface. SDS-PAGE analysis identified protein bands with molecular weights of 18 kDa to >100 kDa which had homologies to OMPs such as GroEL; OmpA, C, E, F, and X; MipA proteins; conjugative plasmid transfer protein; and an outer membrane auto-transporter protein (OMATP). PCR analyses showed that most of the OMP genes were present in all seven Cronobacter species while a few genes (OMATP gene, groEL, ompC, mipA, ctp, and ompX) were absent in some phylogenetically-related species. Microarray analysis demonstrated sequence divergence among the OMP genes that was not captured by PCR. These results support previous findings that OmpA and OmpX may be involved in virulence of Cronobacter, and are packaged within secreted OMVs. These results also suggest that other OMV-packaged OMPs may be involved in roles such as stress response, cell wall and plasmid maintenance, and extracellular transport.
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Affiliation(s)
| | | | | | | | | | - Qiong Q Yan
- Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, WHO Collaborating Centre for Cronobacter, University College, Dublin Dublin, Ireland
| | | | - Boram Lee
- U. S. Food and Drug Administration Laurel, MD, USA
| | - Eunbi Park
- U. S. Food and Drug Administration Laurel, MD, USA
| | - YeonJoo Yoo
- U. S. Food and Drug Administration Laurel, MD, USA
| | | | | | | | - Isha R Patel
- U. S. Food and Drug Administration Laurel, MD, USA
| | | | | | - Séamus Fanning
- Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, WHO Collaborating Centre for Cronobacter, University College, Dublin Dublin, Ireland
| | - Ben D Tall
- U. S. Food and Drug Administration Laurel, MD, USA
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16
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Pathogens of Food Animals: Sources, Characteristics, Human Risk, and Methods of Detection. ADVANCES IN FOOD AND NUTRITION RESEARCH 2017; 82:277-365. [PMID: 28427535 DOI: 10.1016/bs.afnr.2016.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Pathogens associated with food production (livestock) animals come in many forms causing a multitude of disease for humans. For the purpose of this review, these infectious agents can be divided into three broad categories: those that are associated with bacterial disease, those that are associated with viruses, and those that are parasitic in nature. The goal of this chapter is to provide the reader with an overview of the most common pathogens that cause disease in humans through exposure via the food chain and the consequence of this exposure as well as risk and detection methods. We have also included a collection of unusual pathogens that although rare have still caused disease, and their recognition is warranted in light of emerging and reemerging diseases. These provide the reader an understanding of where the next big outbreak could occur. The influence of the global economy, the movement of people, and food makes understanding production animal-associated disease paramount to being able to address new diseases as they arise.
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Transcriptome analysis of Cronobacter sakazakii ATCC BAA-894 after interaction with human intestinal epithelial cell line HCT-8. Appl Microbiol Biotechnol 2016; 100:311-22. [PMID: 26481623 DOI: 10.1007/s00253-015-7053-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/20/2015] [Accepted: 09/30/2015] [Indexed: 10/22/2022]
Abstract
Cronobacter spp. are opportunistic pathogens that are responsible for infections including severe meningitis, septicemia, and necrotizing enterocolitis in neonates and infants. To date, questions still remain regarding the mechanisms of pathogenicity and virulence determinants for each bacterial strain. In this study, we established an in vitro model for Cronobacter sakazakii ATCC BAA-894 infection of HCT-8 human colorectal epithelial cells. The transcriptome profile of C. sakazakii ATCC BAA-894 after interaction with HCT-8 cells was determined using high-throughput whole-transcriptome sequencing (RNA sequencing (RNA-seq)). Gene expression profiles indicated that 139 genes were upregulated and 72 genes were downregulated in the adherent C. sakazakii ATCC BAA-894 strain on HCT-8 cells compared to the cultured bacteria in the cell-free medium. Expressions of some flagella genes and virulence factors involved in adherence were upregulated. High osmolarity and osmotic stress-associated genes were highly upregulated, as well as genes responsible for the synthesis of lipopolysaccharides and outer membrane proteins, iron acquisition systems, and glycerol and glycerophospholipid metabolism. In sum, our study provides further insight into the mechanisms underlying C. sakazakii pathogenesis in the human gastrointestinal tract.
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18
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Chen Q, Tao T, Bie X, Lu F, Li Y, Lu Z. Characterization of a single-chain variable fragment specific to Cronobacter spp. from hybridoma based on outer membrane protein A. J Microbiol Methods 2016; 129:136-143. [DOI: 10.1016/j.mimet.2016.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 07/23/2016] [Accepted: 08/02/2016] [Indexed: 12/30/2022]
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Abstract
The Cronobacter group of pathogens, associated with severe and potentially life-threatening diseases, until recently were classified as a single species, Enterobacter sakazakii. The group was reclassified in 2007 into the genus Cronobacter as a member of the Enterobacteriaceae. This chapter outlines the history behind the epidemiology, analyzes how our understanding of these bacteria has evolved, and highlights the clinical significance the Cronobacter spp. have for neonatal and elderly patient populations and treatment of the associated infections.
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20
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Almajed FS, Forsythe SJ. Cronobacter sakazakii clinical isolates overcome host barriers and evade the immune response. Microb Pathog 2015; 90:55-63. [PMID: 26616163 DOI: 10.1016/j.micpath.2015.11.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 11/17/2015] [Accepted: 11/19/2015] [Indexed: 01/19/2023]
Abstract
Cronobacter sakazakii is the most frequently clinically isolated species of the Cronobacter genus. However the virulence factors of C. sakazakii including their ability to overcome host barriers remains poorly studied. In this study, ten clinical isolates of C. sakazakii were assessed for their ability to invade and translocate through human colonic carcinoma epithelial cells (Caco-2) and human brain microvascular endothelial cells (HBMEC). Their ability to avoid phagocytosis in human macrophages U937 and human brain microglial cells was investigated. Additionally, they were tested for serum sensitivity and the presence of the Cronobacter plasminogen activation gene (cpa) gene, which is reported to confer serum resistance. Our data showed that the clinical C. sakazakii strains invaded and translocated through Caco-2 and HBMEC cell lines and some strains showed significantly higher levels of invasion and translocation. Moreover, C. sakazakii was able to persist and even multiply in phagocytic macrophage and microglial cells. All strains, except one, were able to withstand human serum exposure, the single serum sensitive strain was also the only one which did not encode for the cpa gene. These results demonstrate that C. sakazakii clinical isolates are able to overcome host barriers and evade the host immune response indicating their capacity to cause diseases such as necrotizing enterocolitis (NEC) and meningitis. Our data showed for the first time the ability of C. sakazakii clinical isolates to survive and multiply within human microglial cells. Additionally, it was shown that C. sakazakii clinical strains have the capacity to translocate through the Caco-2 and HBMEC cell lines paracellularly.
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Affiliation(s)
- Faisal S Almajed
- Pathogen Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG 11 8NS, UK; College of Applied Medical Sciences, King Saud bin Abdulaziz University for Health Sciences, Riyadh 11426, Saudi Arabia
| | - Stephen J Forsythe
- Pathogen Research Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG 11 8NS, UK.
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21
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Ye Y, Li H, Ling N, Han Y, Wu Q, Xu X, Jiao R, Gao J. Identification of potential virulence factors of Cronobacter sakazakii isolates by comparative proteomic analysis. Int J Food Microbiol 2015; 217:182-8. [PMID: 26546912 DOI: 10.1016/j.ijfoodmicro.2015.08.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 08/24/2015] [Accepted: 08/30/2015] [Indexed: 01/18/2023]
Abstract
Cronobacter is a group of important foodborne pathogens associated with neonatal meningitis, septicemia, and necrotizing enterocolitis. Among Cronobacter species, Cronobacter sakazakii is the most common species in terms of isolation frequency. However, the molecular basis involved in virulence differences among C. sakazakii isolates is still unknown. In this study, based on the determination of virulence differences of C. sakazakii G362 (virulent isolate) and L3101 (attenuated isolate) through intraperitoneal injection, histopathologic analysis (small intestine, kidney, and liver) further confirmed virulence differences. Thereafter, the potential virulence factors were determined using two-dimensional electrophoresis (2-DE) coupled with MALDI/TOP/TOF mass spectrometry. Among a total of 36 protein spots showing differential expression (fold change>1.2), we identified 31 different proteins, of which the expression abundance of 22 was increased in G362. These up-regulated proteins in G362 mainly contained DNA starvation/stationary phase protection protein Dps, OmpA, LuxS, ATP-dependent Clp protease ClpC, and ABC transporter substrate-binding proteins, which might be involved in virulence of C. sakazakii. This is the first report to determine the potential virulence factors of C. sakazakii isolates at the proteomic levels.
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Affiliation(s)
- Yingwang Ye
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Hui Li
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Na Ling
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China; State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Yongjia Han
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Qingping Wu
- State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
| | - Xiaoke Xu
- State Key Laboratory of Applied Microbiology, South China (the Ministry-Province Joint Development), Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China
| | - Rui Jiao
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Jina Gao
- School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
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Genotyping and Source Tracking of Cronobacter sakazakii and C. malonaticus Isolates from Powdered Infant Formula and an Infant Formula Production Factory in China. Appl Environ Microbiol 2015; 81:5430-9. [PMID: 26048942 DOI: 10.1128/aem.01390-15] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 05/26/2015] [Indexed: 11/20/2022] Open
Abstract
Cronobacter spp. (formerly defined as Enterobacter sakazakii) are opportunistic bacterial pathogens of both infants and adults. In this study, we analyzed 70 Cronobacter isolates from powdered infant formula (PIF) and an infant formula production facility in China to determine possible contamination routes. The strains were profiled by multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), PCR-based O-antigen serotyping, and ompA and rpoB sequence analyses. The isolates were primarily Cronobacter sakazakii (66/70) or Cronobacter malonaticus (4/70). The strains were divided into 38 pulsotypes (PTs) using PFGE and 19 sequence types (STs) by MLST. In contrast, rpoB and ompA sequence analyses divided the strains into 10 overlapping clusters each. PCR serotyping of the 66 C. sakazakii and 4 C. malonaticus strains resulted in the identification of four C. sakazakii serotypes (O1, O2, O4, and O7) and a single C. malonaticus serotype, O2. The dominant C. sakazakii sequence types from PIF and an infant formula production factory in China were C. sakazakii clonal complex 4 (CC4) (n = 19), ST1 (n = 14), and ST64 (n = 11). C. sakazakii CC4 is a clonal lineage strongly associated with neonatal meningitis. In the process of manufacturing PIF, the spray-drying, fluidized-bed-drying, and packing areas were the main areas with Cronobacter contamination. C. sakazakii strains with the same pulsotypes (PT3 and PT2) and sequence types (ST1 and ST64) were isolated both from processing equipment and from the PIF finished product.
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Singh N, Goel G, Raghav M. Insights into virulence factors determining the pathogenicity of Cronobacter sakazakii. Virulence 2015; 6:433-40. [PMID: 25950947 PMCID: PMC4601314 DOI: 10.1080/21505594.2015.1036217] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 03/25/2015] [Accepted: 03/26/2015] [Indexed: 02/07/2023] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen associated with outbreaks of life-threatening necrotizing enterocolitis, meningitis and sepsis in neonates and infants. The pathogen possesses an array of virulence factors which aid in tissue adhesion, invasion and host cell injury. Although the identification and validation of C. sakazakii virulence factors has been hindered by availability of suitable neonatal animal model, various studies has reported outer membrane protein A (ompA) as a potential virulence marker. Various other plasmid associated genes such as filamentous hemagglutinin (fhaBC), Cronobacter plasminogen activator (cpa) and genes responsible for iron acquisition (eitCBAD and iucABD/iutA) have been reported in different strains of C. sakazakii. Besides these proposed virulence factors, several biophysical growth factors such as formation of biofilms and resistance to various environmental stresses also contributes to the pathogenic potential of this pathogen. This review provides an update on virulence determinants associated with the pathogenesis of C. sakazakii. The potential reservoirs of the pathogen, mode of transmission and epidemiology are also discussed.
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Affiliation(s)
- Niharika Singh
- Department of Biotechnology and Bioinformatics; Jaypee University of Information Technology; Waknaghat, Solan, India
| | - Gunjan Goel
- Department of Biotechnology and Bioinformatics; Jaypee University of Information Technology; Waknaghat, Solan, India
| | - Mamta Raghav
- Department of Biotechnology and Bioinformatics; Jaypee University of Information Technology; Waknaghat, Solan, India
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Abstract
Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency among premature infants. Although a large body of research has focused on understanding its pathogenesis, the exact mechanism has not been elucidated. Of particular interest is the potential causative role of infectious culprits in the development of NEC. A variety of reports describe bacterial, viral, and fungal infections occurring in association with NEC; however, no single organism has emerged as being definitively involved in NEC pathogenesis. In this review, the authors summarize the literature on infectious causes of NEC.
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Affiliation(s)
- Sarah A Coggins
- Vanderbilt University School of Medicine, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - James L Wynn
- Department of Pediatrics, Monroe Carell Jr. Children's Hospital at Vanderbilt, Vanderbilt University, 2215 B Garland Avenue, 1125 MRB IV/Light Hall, Nashville, TN 37232, USA
| | - Jörn-Hendrik Weitkamp
- Department of Pediatrics, Monroe Carell Jr. Children's Hospital at Vanderbilt, Vanderbilt University, 2215 B Garland Avenue, 1125 MRB IV/Light Hall, Nashville, TN 37232, USA.
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25
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Plasmid-encoded MCP is involved in virulence, motility, and biofilm formation of Cronobacter sakazakii ATCC 29544. Infect Immun 2014; 83:197-204. [PMID: 25332122 DOI: 10.1128/iai.02633-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The aim of this study was to elucidate the function of the plasmid-borne mcp (methyl-accepting chemotaxis protein) gene, which plays pleiotropic roles in Cronobacter sakazakii ATCC 29544. By searching for virulence factors using a random transposon insertion mutant library, we identified and sequenced a new plasmid, pCSA2, in C. sakazakii ATCC 29544. An in silico analysis of pCSA2 revealed that it included six putative open reading frames, and one of them was mcp. The mcp mutant was defective for invasion into and adhesion to epithelial cells, and the virulence of the mcp mutant was attenuated in rat pups. In addition, we demonstrated that putative MCP regulates the motility of C. sakazakii, and the expression of the flagellar genes was enhanced in the absence of a functional mcp gene. Furthermore, a lack of the mcp gene also impaired the ability of C. sakazakii to form a biofilm. Our results demonstrate a regulatory role for MCP in diverse biological processes, including the virulence of C. sakazakii ATCC 29544. To the best of our knowledge, this study is the first to elucidate a potential function of a plasmid-encoded MCP homolog in the C. sakazakii sequence type 8 (ST8) lineage.
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26
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Jaradat ZW, Al Mousa W, Elbetieha A, Al Nabulsi A, Tall BD. Cronobacter spp.--opportunistic food-borne pathogens. A review of their virulence and environmental-adaptive traits. J Med Microbiol 2014; 63:1023-1037. [PMID: 24878566 DOI: 10.1099/jmm.0.073742-0] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The genus Cronobacter consists of a diverse group of Gram-negative bacilli and comprises seven species: Cronobacter sakazakii, Cronobacter malonaticus, Cronobacter muytjensii, Cronobacter turicensis, Cronobacter dublinensis, Cronobacter universalis and Cronobacter condimenti. Cronobacter are regarded as opportunistic pathogens, and have been implicated in newborn and infant infections, causing meningitis, necrotizing enterocolitis and bacteraemia or sepsis. Cronobacter virulence is believed to be due to multiple factors. Some strains were found to produce diarrhoea or cause significant fluid accumulation in suckling mice. Two iron acquisition systems (eitCBAD and iucABCD/iutA), Cronobacter plasminogen activator gene (cpa), a 17 kb type VI secretion system (T6SS), and a 27 kb filamentous haemagglutinin gene (fhaBC) and associated putative adhesins locus are harboured on a family of RepFIB-related plasmids (pESA3 and pCTU1), suggesting that these are common virulence plasmids; 98% of 229 tested Cronobacter strains possessed these plasmids. Even though pESA3 and pCTU1 share a common backbone composed of the repA gene and eitCBAD and iucABCD/iutA gene clusters, the presence of cpa, T6SS and FHA loci depended on species, demonstrating a strong correlation with the presence of virulence traits, plasmid type and species. Other factors were observed, in that Cronobacter form biofilms, and show unusual resistance to heat, dry and acid stress growth conditions. The outer-membrane protein A is probably one of the best-characterized virulence markers of Cronobacter. Furthermore, it was reported that Cronobacter employ phosphatidylinositide 3-kinase/Akt signalling, which activates protein kinase C-α and impairs the host cell's mitogen-activated protein kinase pathway, in order to invade cells. Cronobacter can also use immature dendritic cells and macrophages to escape the immune response. This review addresses the various virulence and environmental-adaptive characteristics possessed by members of the genus Cronobacter.
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Affiliation(s)
- Ziad W Jaradat
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan
| | - Waseem Al Mousa
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan
| | - Ahmed Elbetieha
- Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan
| | - Anas Al Nabulsi
- Department of Nutrition and Food Technology, Jordan University of Science and Technology, PO Box 3030, Irbid 22110, Jordan
| | - Ben D Tall
- Food and Drug Administration, Center for Food Safety and Applied Nutrition, Division of Virulence Assessment, 8301 Muirkirk Road, Laurel, MD 20708, USA
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27
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Sub-inhibitory concentrations of trans-cinnamaldehyde attenuate virulence in Cronobacter sakazakii in vitro. Int J Mol Sci 2014; 15:8639-55. [PMID: 24837831 PMCID: PMC4057751 DOI: 10.3390/ijms15058639] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2014] [Revised: 04/28/2014] [Accepted: 05/05/2014] [Indexed: 12/21/2022] Open
Abstract
Cronobacter sakazakii is a foodborne pathogen, which causes a life-threatening form of meningitis, necrotizing colitis and meningoencephalitis in neonates and children. Epidemiological studies implicate dried infant formula as the principal source of C. sakazakii. In this study, we investigated the efficacy of sub-inhibitory concentrations (SIC) of trans-cinnamaldehyde (TC), an ingredient in cinnamon, for reducing C. sakazakii virulence in vitro using cell culture, microscopy and gene expression assays. TC significantly (p ≤ 0.05) suppressed C. sakazakii adhesion to and invasion of human and rat intestinal epithelial cells, and human brain microvascular endothelial cells. In addition, TC inhibited C. sakazakii survival and replication in human macrophages. We also observed that TC reduced the ability of C. sakazakii to cause cell death in rat intestinal cells, by inhibiting nitric oxide production. Results from gene expression studies revealed that TC significantly downregulated the virulence genes critical for motility, host tissue adhesion and invasion, macrophage survival, and LPS (Lipopolysaccharide) synthesis in C. sakazakii. The efficacy of TC in attenuating these major virulence factors in C. sakazakii underscores its potential use in the prevention and/or control of infection caused by this pathogen.
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Ye Y, Li H, Wu Q, Zhang J, Lu Y. TheCronobactersp. in milk and dairy products: Detection and typing. INT J DAIRY TECHNOL 2014. [DOI: 10.1111/1471-0307.12111] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yingwang Ye
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei 230009 China
- Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application; Guangdong Institute of Microbiology; Guangzhou 510070 China
| | - Hui Li
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei 230009 China
- Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application; Guangdong Institute of Microbiology; Guangzhou 510070 China
| | - Qingping Wu
- Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application; Guangdong Institute of Microbiology; Guangzhou 510070 China
| | - Jumei Zhang
- Guangdong Provincial Key Laboratory of Microbiology Culture Collection and Application; Guangdong Institute of Microbiology; Guangzhou 510070 China
| | - Yudong Lu
- School of Biotechnology and Food Engineering; Hefei University of Technology; Hefei 230009 China
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Fleites LA, Mensi I, Gargani D, Zhang S, Rott P, Gabriel DW. Xanthomonas albilineans OmpA1 appears to be functionally modular and both the OMC and C-like domains are necessary for leaf scald disease of sugarcane. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:1200-1210. [PMID: 23758144 DOI: 10.1094/mpmi-01-13-0002-r] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Several EZ-Tn5 insertions in gene locus XALc_0557 (OmpA1) of the sugarcane leaf scald pathogen Xanthomonas albilineans XaFL07-1 were previously found to strongly affect pathogenicity and endophytic stalk colonization. XALc_0557 has a predicted OmpA N-terminal outer membrane channel (OMC) domain and an OmpA C-like domain. Further analysis of mutant M468, with an EZ-Tn5 insertion in the upstream OMC domain coding region, revealed impaired epiphytic and endophytic leaf survival, impaired resistance to sodium dodecyl sulfate (SDS), structural defects in the outer membrane (OM), and hyperproduction of OM vesicles. Cloned full-length XALc_0557 complemented M468 for all phenotypes tested, including pathogenicity, resistance to SDS, and ability to survive both endophytically and epiphytically. Another construct, pCT47.3, which expressed only the C-like domain of XALc_0557, restored resistance to SDS in M468 but failed to complement any other mutant phenotype, indicating that the C-like domain functioned independently of the OMC domain to help maintain OM integrity. pCT47.3 also complemented pathogenicity, resistance to SDS, and stalk colonization in mutant M1152, which carries an EZ-Tn5 insert in the C-like coding region, indicating that both predicted domains are modular and necessary but neither is sufficient for X. albilineans pathogenicity, endophytic survival in, and epiphytic survival on sugarcane.
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Cronobacter: an emerging opportunistic pathogen associated with neonatal meningitis, sepsis and necrotizing enterocolitis. J Perinatol 2013; 33:581-5. [PMID: 23538645 DOI: 10.1038/jp.2013.26] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 01/24/2013] [Accepted: 02/11/2013] [Indexed: 11/08/2022]
Abstract
Members of the genus Cronobacter are an emerging group of opportunist Gram-negative pathogens. This genus was previously thought to be a single species, called Enterobacter sakazakii. Cronobacter spp. typically affect low-birth-weight neonates, causing life-threatening meningitis, sepsis and necrotizing enterocolitis. Outbreaks of disease have been associated with contaminated infant formula, although the primary environmental source remains elusive. Advanced understanding of these bacteria and better classification has been obtained by improved detection techniques and genomic analysis. Research has begun to characterize the virulence factors and pathogenic potential of Cronobacter. Investigations into sterilization techniques and protocols for minimizing the risk of contamination have been reviewed at national and international forums. In this review, we explore the clinical impact of Cronobacter neonatal and pediatric infections, discuss virulence and pathogenesis, and review prevention and treatment strategies.
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Confer AW, Ayalew S. The OmpA family of proteins: Roles in bacterial pathogenesis and immunity. Vet Microbiol 2013; 163:207-22. [DOI: 10.1016/j.vetmic.2012.08.019] [Citation(s) in RCA: 158] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 08/23/2012] [Indexed: 10/27/2022]
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Ruan J, Li M, Liu YP, Li YQ, Li YX. Rapid and sensitive detection of Cronobacter spp. (previously Enterobacter sakazakii) in food by duplex PCR combined with capillary electrophoresis–laser-induced fluorescence detector. J Chromatogr B Analyt Technol Biomed Life Sci 2013; 921-922:15-20. [DOI: 10.1016/j.jchromb.2013.01.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2012] [Revised: 01/06/2013] [Accepted: 01/11/2013] [Indexed: 12/01/2022]
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Wang J, Du XJ, Lu XN, Wang S. Immunoproteomic identification of immunogenic proteins in Cronobacter sakazakii strain BAA-894. Appl Microbiol Biotechnol 2013; 97:2077-91. [PMID: 23371297 DOI: 10.1007/s00253-013-4720-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 01/12/2013] [Accepted: 01/15/2013] [Indexed: 11/30/2022]
Abstract
Cronobacter spp. are emerging opportunistic pathogens. Cronobacter sakazakii is considered as the predominant species in all infections. So far, our understanding of the species' immunogens and potential virulence factors of Cronobacter spp. remains limited. In this study, an immunoproteomic approach was used to investigate soluble and insoluble proteins from the genome-sequenced strain C. sakazakii ATCC BAA-894. Proteins were separated using two-dimensional electrophoresis, detected by Western blotting with polyclonal antibodies of C. sakazakii BAA-894, and identified using tandem mass spectrometry (MALDI-MS and MALDI-MS/MS, MS/MSMS). A total of 11 immunoreactive proteins were initially identified in C. sakazakii BAA-894, including two outer membrane proteins, four periplasmic proteins, and five cytoplasmic proteins. In silico functional analysis of the 11 identified proteins indicated three proteins that were initially described as immunogens of pathogenic bacteria. For the remaining eight proteins, one protein was categorized as a potential virulence factor involved in protection against reactive oxygen species, and seven proteins were considered to play potential roles in adhesion, invasion, and biofilm formation. To our knowledge, this is the first time that immunogenic proteins of C. sakazakii BAA-894 have been identified as immunogens and potential virulence factors by an immunoproteomics approach. Future studies should investigate the roles of these proteins in bacterial pathogenesis and modulation of host immune responses during infection to identify their potential as molecular therapeutic targets.
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Affiliation(s)
- Jian Wang
- Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin University of Science & Technology, Tianjin 300457, People's Republic of China
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Cruz-Córdova A, Rocha-Ramírez LM, Ochoa SA, González-Pedrajo B, Gónzalez-Pedrajo B, Espinosa N, Eslava C, Hernández-Chiñas U, Mendoza-Hernández G, Rodríguez-Leviz A, Valencia-Mayoral P, Sadowinski-Pine S, Hernández-Castro R, Estrada-García I, Muñoz-Hernández O, Rosas I, Xicohtencatl-Cortes J. Flagella from five Cronobacter species induce pro-inflammatory cytokines in macrophage derivatives from human monocytes. PLoS One 2012; 7:e52091. [PMID: 23284883 PMCID: PMC3528739 DOI: 10.1371/journal.pone.0052091] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 11/12/2012] [Indexed: 01/26/2023] Open
Abstract
Cronobacter spp. are opportunistic pathogens linked to lie-threatening infections in neonates and contaminated powdered infant formula that has been epidemiologically associated with these cases. Clinical symptoms of Cronobacter include necrotizing enterocolitis, bacteremia, and meningitis. Flagella from C. sakazakii are involved in biofilm formation and its adhesion to epithelial cells. We investigated the role of flagella from C. sakazakii ST1 and ST4, C. malonaticus, C. muytjensii, C. turicensis and C. dublinensis during the activation of cytokines (IL-8, TNF-α, and IL-10) in macrophage derivatives from human monocytes, which has not been extensively studied. The production and identity of flagella from the five Cronobacter species were visualized and recognized with anti-flagella antibodies by immunogold labeling through transmission electron microscopy. Purified flagella were dissociated into monomers in 12% SDS-PAGE Coomassie blue-stained gels showing a band of ∼28 kDa and, in addition, mass spectrometry revealed the presence of several peptides that correspond to flagellin. Flagella (100 ng) induced the release of IL-8 (3314–6025 pg/ml), TNF-α (39–359 pg/ml), and IL-10 (2–96 pg/ml), in macrophage isolates from human monocytes and similar results were obtained when flagella were dissociated into monomers. Inhibition assays using three dilutions of anti-flagella antibodies (1∶10, 1∶100, and 1∶200) suppressed the secretion of IL-8, TNF-α, and IL-10 between 95–100% using 100 ng of protein. A transfection assay using 293-hTLR5 cells showed IL-8 release of 197 pg/ml and suppression in the secretion of IL-8 when anti-hTLR5-IgA antibodies were used at different concentrations. These observations suggest that flagella and flagellin are involved in an inflammatory response dependent on TLR5 recognition, which could contribute to the pathogenesis of the bacteria.
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Affiliation(s)
- Ariadnna Cruz-Córdova
- Laboratorio de Bacteriología Intestinal, Departamento de Infectología, Hospital Infantil de México Federico Gómez, México D.F., México
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Possible roles of LysR-type transcriptional regulator (LTTR) homolog as a global regulator in Cronobacter sakazakii ATCC 29544. Int J Med Microbiol 2012; 302:270-5. [DOI: 10.1016/j.ijmm.2012.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2011] [Revised: 05/28/2012] [Accepted: 06/04/2012] [Indexed: 02/07/2023] Open
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Complete genome sequence of the opportunistic food-borne pathogen Cronobacter sakazakii ES15. J Bacteriol 2012; 194:4438-9. [PMID: 22843579 DOI: 10.1128/jb.00841-12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cronobacter sakazakii is an emerging pathogen associated with several outbreaks of food-borne illness in premature infants. To characterize its physiology and pathogenicity at the molecular level, C. sakazakii ES15 was isolated and its genome was completely sequenced and analyzed. Here, the results are announced and major findings from its annotation data are reported.
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Krishnan S, Prasadarao NV. Outer membrane protein A and OprF: versatile roles in Gram-negative bacterial infections. FEBS J 2012; 279:919-31. [PMID: 22240162 DOI: 10.1111/j.1742-4658.2012.08482.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Outer membrane protein A (OmpA) is an abundant protein of Escherichia coli and other enterobacteria and has a multitude of functions. Although the structural features and porin function of OmpA have been well studied, its role in the pathogenesis of various bacterial infections has emerged only during the last decade. The four extracellular loops of OmpA interact with a variety of host tissues for adhesion to and invasion of the cell and for evasion of host-defense mechanisms when inside the cell. This review describes how various regions present in the extracellular loops of OmpA contribute to the pathogenesis of neonatal meningitis induced by E. coli K1 and to many other functions. In addition, the function of OmpA-like proteins, such as OprF of Pseudomonas aeruginosa, is discussed.
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Affiliation(s)
- Subramanian Krishnan
- Division of Infectious Diseases, Department of Pediatrics, The Saban Research Institute, Children's Hospital Los Angeles, CA, USA
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Liu DX, Zhao WD, Fang WG, Chen YH. cPLA2α-mediated actin rearrangements downstream of the Akt signaling is required for Cronobacter sakazakii invasion into brain endothelial cells. Biochem Biophys Res Commun 2011; 417:925-30. [PMID: 22138395 DOI: 10.1016/j.bbrc.2011.11.079] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 11/16/2011] [Indexed: 12/20/2022]
Abstract
Cronobacter sakazakii (C. sakazakii) is an opportunistic pathogen that causes sepsis and meningitis in neonate. The molecular mechanism involved in the pathogenesis of C. sakazakii meningitis remains unclear. In this study, we found that C. sakazakii invasion was significantly decreased in human brain microvascular endothelial cells (HBMEC) treated with cytosolic phospholipases A(2)α (cPLA(2)α) inhibitor. Increased phosphorylation of cPLA(2)α was observed in HBMEC infected with C. sakazakii, which was prevented by treatment with cPLA(2)α inhibitor. cPLA(2)α knockdown in HBMEC significantly attenuated C. sakazakii invasion into HBMEC. Immunofluorescence demonstrated that the rearrangements of actin filaments in HBMEC induced by C. sakazakii were effectively blocked by either treatment with cPLA(2)α inhibitor or transfection with cPLA(2)α siRNA. Interestingly, we found that C. sakazakii infection promoted the aggregation of phosphorylated cPLA(2)α, which was associated with depolymerized actin filaments in HBMEC. Furthermore, our data revealed that cPLA(2)α acts downstream of Akt signaling pathway in HBMEC stimulated with C. sakazakii. Taken together, our results illustrated that cPLA(2)α-mediated actin filament rearrangements downstream of Akt activation is required for C. sakazakii invasion into brain endothelial cells.
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Affiliation(s)
- Dong-Xin Liu
- Department of Developmental Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Heping District, Shenyang, China
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Giri CP, Shima K, Tall BD, Curtis S, Sathyamoorthy V, Hanisch B, Kim KS, Kopecko DJ. Cronobacter spp. (previously Enterobacter sakazakii) invade and translocate across both cultured human intestinal epithelial cells and human brain microvascular endothelial cells. Microb Pathog 2011; 52:140-7. [PMID: 22023990 DOI: 10.1016/j.micpath.2011.10.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 10/07/2011] [Accepted: 10/10/2011] [Indexed: 12/21/2022]
Abstract
The mechanism of Cronobacter pathogenesis in neonatal meningitis and potential virulence factors (aside from host cell invasion ability) remain largely unknown. To ascertain whether Cronobacter can invade and transcytose across intestinal epithelial cells, enter into the blood stream and then transcytose across the blood-brain-barrier, we have utilized human intestinal INT407 and Caco-2 cells and brain microvascular endothelial cell (HBMEC) monolayers on Transwell filters as experimental model systems. Our data indicate a wide range of heterogeneity with respect to invasion efficiency among twenty-three Cronobacter isolates screened. For selected isolates, we observed significant levels of transcytosis for Cronobacter sakazakii across tight monolayers of both Caco-2 and HBMEC, mimicking in vivo ability to cross the intestine as well as the blood brain barrier, and at a frequency equivalent to that of a control meningitis-causing Escherichia coli K1 strain. Finally, EM analysis demonstrated intracellular Cronobacter bacteria within host vacuoles in HBMEC, as well as transcytosed bacteria at the basolateral surface. These data reveal that certain Cronobacter isolates can invade and translocate across both cultured human intestinal epithelial cells and HBMEC, thus demonstrating a potential path for neonatal infections of the central nervous system (CNS) following oral ingestion.
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Affiliation(s)
- Chandrakant P Giri
- Laboratory of Enteric and Sexually Transmitted Diseases, DBPAP, OVRR, Center for Biologics Evaluation and Research, Food & Drug Administration, Bethesda, MD 20892, USA.
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Cruz A, Xicohtencatl-Cortes J, González-Pedrajo B, Bobadilla M, Eslava C, Rosas I. Virulence traits inCronobacterspecies isolated from different sources. Can J Microbiol 2011; 57:735-44. [DOI: 10.1139/w11-063] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Ariadnna Cruz
- Facultad de Medicina-Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, 04510 México D.F
| | - Juan Xicohtencatl-Cortes
- Laboratorio de Bacteriología Intestinal, Hospital Infantil de México Federico Gómez, 01900 México D.F
| | - Bertha González-Pedrajo
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 70-243, 04510 México, D.F
| | - Miriam Bobadilla
- Microbiología Clínica, Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán”, 14000 México, D.F
| | - Carlos Eslava
- Facultad de Medicina, Salud Pública, Universidad Nacional Autónoma de México, 04510 México, D.F
| | - Irma Rosas
- Laboratorio de Aerobiología, Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México, 04510 México, D.F
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Jaradat ZW, Rashdan AM, Ababneh QO, Jaradat SA, Bhunia AK. Characterization of surface proteins of Cronobacter muytjensii using monoclonal antibodies and MALDI-TOF Mass spectrometry. BMC Microbiol 2011; 11:148. [PMID: 21702985 PMCID: PMC3224122 DOI: 10.1186/1471-2180-11-148] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 06/25/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cronobacter spp. is a newly emerging pathogen that causes meningitis in infants and other diseases in elderly and immunocompromised individuals. This study was undertaken to investigate surface antigenic determinants in Cronobacter spp. using monoclonal antibodies (MAbs) and MALDI-TOF Mass spectrometry. RESULTS Spleenocytes from mice that were immunized with heat-killed (20 min, 80°C) Cronobacter cells were fused with SP2 myeloma cells. Five desirable MAbs (A1, B5, 2C2, C5 and A4) were selected. MAbs A1, B5, 2C2 and C5 were of IgG2a isotype while A4 was an IgM. Specificity of the MAbs was determined by using immunoblotting with outer membrane protein preparations (OMPs) extracted from 12 Cronobacter and 6 non-Cronobacter bacteria. All MAbs recognized proteins with molecular weight ranging between 36 and 49 kDa except for one isolate (44) in which no OMPs were detected. In addition, MAbs recognized two bands (38-41 kDa) in four of the non-Cronobacter bacteria. Most of the proteins recognized by the MAbs were identified by MALDI-TOF peptide sequencing and appeared to be heterogeneous with the identities of some of them are still unknown. All MAbs recognized the same epitope as determined by an additive Index ELISA with their epitopes appeared to be conformational rather than sequential. Further, none of the MAbs recognized purified LPS from Cronobacter spp. Specificity of the MAbs toward OMPs was further confirmed by transmission electron microscopy. CONCLUSIONS Results obtained in this study highlight the immunological cross-reactivity among Cronobacter OMPs and their Enterobacteriaceae counterparts. Nevertheless, the identity of the identified proteins appeared to be different as inferred from the MALDI-TOF sequencing and identification.
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Affiliation(s)
- Ziad W Jaradat
- Department of Biotechnology and Genetic Engineering, PO Box 3030, Jordan University of Science and Technology, Irbid 22110, Jordan.
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Rott P, Fleites L, Marlow G, Royer M, Gabriel DW. Identification of new candidate pathogenicity factors in the xylem-invading pathogen Xanthomonas albilineans by transposon mutagenesis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:594-605. [PMID: 21190440 DOI: 10.1094/mpmi-07-10-0156] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Xanthomonas albilineans is a xylem-invading pathogen that produces the toxin albicidin that blocks chloroplast differentiation, resulting in disease symptoms of sugarcane leaf scald. In contrast to other xanthomonads, X. albilineans does not possess a hypersensitive response and pathogenicity type III secretion system and does not produce xanthan gum. Albicidin is the only previously known pathogenicity factor in X. albilineans, yet albicidin-deficient mutant strains are still able to efficiently colonize sugarcane. To identify additional host adaptation or pathogenicity factors, sugarcane 'CP80-1743' was inoculated with 1,216 independently derived Tn5 insertions in X. albilineans XaFL07-1 from Florida. Sixty-one Tn5 mutants were affected in development of leaf symptoms or in stalk colonization. The Tn5 insertion sites of these mutants were determined and the interrupted genes were identified using the recently available genomic DNA sequence of X. albilineans GPE PC73 from Guadeloupe. Several pathogenicity-related loci that were not previously reported in Xanthomonas spp. were identified, including loci encoding hypothetical proteins, a membrane fusion protein conferring resistance to novobiocin, transport proteins, TonB-dependent outer-membrane transporters, and an OmpA family outer-membrane protein.
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Affiliation(s)
- Philippe Rott
- UMR BGPI, CIRAD, TA A-54/K, Campus International de Baillarguet, 34398 Montpellier Cedex 5, France.
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Hu Q, Han X, Zhou X, Ding C, Zhu Y, Yu S. OmpA is a virulence factor of Riemerella anatipestifer. Vet Microbiol 2011; 150:278-83. [PMID: 21349662 DOI: 10.1016/j.vetmic.2011.01.022] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 01/13/2011] [Accepted: 01/24/2011] [Indexed: 10/18/2022]
Abstract
Riemerella anatipestifer infection is probably the most economically important disease of farm ducks worldwide. The pathogen R. anatipestifer causes septicemia anserum exsudativa in ducks, but little is known about the molecular basis of its pathogenesis and the virulence factors involved. In this study, by deleting ompA gene from R. anatipestifer serotype 2 strain Th4, we constructed a mutant strain Th4ΔompA to investigate whether R. anatipestifer OmpA is an important virulence factor. Results showed that although the growth curve, bacterial and colony morphology of Th4ΔompA in tryptic soybean broth (TSB) or on TSB agar were similar to its parent strain Th4, the adhesion and invasion capacities of mutant strain to Vero cells were decreased significantly. Furthermore, the median lethal dose (LD(50)) of both strains was determined to measure the virulence with 10-day-old Cherry Valley ducklings. The results showed that LD(50) of Th4ΔompA mutant was >10(10) colony forming units (CFU), it was attenuated significantly in comparison with that of Th4 which LD(50) was 4.41 × 10(8) CFU. Additional analysis indicated that blood bacterial loading of ducklings infected with the Th4ΔompA mutant were much lower than those of Th4-infected ducklings. The results demonstrate that OmpA is a virulence factor of R. anatipestifer, and that it may act as an adhesin.
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Affiliation(s)
- Qinghai Hu
- Shanghai Veterinary Research Institute, The Chinese Academy of Agricultural Sciences (CAAS), 518 Ziyue Road, Shanghai 200241, PR China
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45
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Cpa, the outer membrane protease of Cronobacter sakazakii, activates plasminogen and mediates resistance to serum bactericidal activity. Infect Immun 2011; 79:1578-87. [PMID: 21245266 DOI: 10.1128/iai.01165-10] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cronobacter spp. are emerging neonatal pathogens in humans, associated with outbreaks of meningitis and sepsis. To cause disease, they must survive in blood and invade the central nervous system by penetrating the blood-brain barrier. C. sakazakii BAA-894 possesses an ~131-kb plasmid (pESA3) that encodes an outer membrane protease (Cpa) that has significant identity to proteins that belong to the Pla subfamily of omptins. Members of this subfamily of proteins degrade a number of serum proteins, including circulating complement, providing protection from the complement-dependent serum killing. Moreover, proteins of the Pla subfamily can cause uncontrolled plasmin activity by converting plasminogen to plasmin and inactivating the plasmin inhibitor α2-antiplasmin (α2-AP). These reactions enhance the spread and invasion of bacteria in the host. In this study, we found that an isogenic cpa mutant showed reduced resistance to serum in comparison to its parent C. sakazakii BAA-894 strain. Overexpression of Cpa in C. sakazakii or Escherichia coli DH5α showed that Cpa proteolytically cleaved complement components C3, C3a, and C4b. Furthermore, a strain of C. sakazakii overexpressing Cpa caused a rapid activation of plasminogen and inactivation of α2-AP. These results strongly suggest that Cpa may be an important virulence factor involved in serum resistance, as well as in the spread and invasion of C. sakazakii.
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Li Q, Zhao WD, Zhang K, Fang WG, Hu Y, Wu SH, Chen YH. PI3K-dependent host cell actin rearrangements are required for Cronobacter sakazakii invasion of human brain microvascular endothelial cells. Med Microbiol Immunol 2010; 199:333-40. [PMID: 20809254 DOI: 10.1007/s00430-010-0168-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Indexed: 10/19/2022]
Abstract
Cronobacter sakazakii (C. sakazakii) is an opportunistic pathogen that can cause neonatal sepsis and meningitis. The mechanism involved in the pathogenesis of C. sakazakii meningitis remains largely unknown. Previous studies indicated that bacterial invasion of brain microvascular endothelial cells is required for penetration into the central nervous system. In this study, we found that C. sakazakii invasion of human brain microvascular endothelial cells (HBMEC) was significantly inhibited by cytochalasin D, a disrupting agent of actin microfilaments. Disassembly of actin stress fibers and cortical actin fibers was observed in HBMEC infected with C. sakazakii. C. sakazakii infection leads to increased Akt phosphorylation in HBMEC, which was blocked by treatment with PI3K inhibitors. Meanwhile, PI3K and Akt inhibitors significantly inhibited C. sakazakii invasion of HBMEC. Our further results illustrated that the C. sakazakii-induced Akt activation and C. sakazakii invasion were attenuated in HBMEC transfected with dominant-negative PI3K (Δp110). More importantly, the actin filaments rearrangements in HBMEC induced by C. sakazakii were effectively blocked by PI3K inhibitors treatment and transfection with Δp110. Taken together, our findings demonstrated that PI3K-mediated actin rearrangements are required for C. sakazakii invasion of HBMEC.
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Affiliation(s)
- Qiang Li
- Department of Developmental Biology, Key Laboratory of Cell Biology, Ministry of Public Health, China Medical University, Heping District, Shenyang, China
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Healy B, Cooney S, O'Brien S, Iversen C, Whyte P, Nally J, Callanan JJ, Fanning S. Cronobacter (Enterobacter sakazakii): an opportunistic foodborne pathogen. Foodborne Pathog Dis 2010; 7:339-50. [PMID: 19958103 DOI: 10.1089/fpd.2009.0379] [Citation(s) in RCA: 196] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Cronobacter spp. (Enterobacter sakazakii) are a recently described genus that is comprised of six genomospecies. The classification of these organisms was revised based on a detailed polyphasic taxonomic study. Cronobacter spp. are regarded as ubiquitous organisms having been isolated from a wide variety of foods. These bacteria are opportunistic pathogens and are linked with life-threatening infections in neonates. Clinical symptoms of Cronobacter infection include necrotizing enterocolitis, bacteremia, and meningitis, with case fatality rates of 50-80% being reported. Contaminated powdered infant formula has been epidemiologically linked with infections. Recently, infections among immunocompromised adults, mainly the elderly, have also been reported. A high tolerance to osmotic stress and elevated temperatures contribute to the survival of Cronobacter spp. in dried foods such as powdered infant formula. Controlling the organism in the production environment, thereby reducing dissemination, necessitates the provision of suitable diagnostic tools. Studies demonstrated that a high degree of variability exists amongst the phenotypic-based methods used to identify Cronobacter spp. However, advances in molecular detection and subtyping techniques have significantly improved the identification and characterization of Cronobacter spp. The dose required to induce infection has yet to be determined. In vitro virulence studies have shown that Cronobacter spp. may survive in macrophage cells and efficiently attach to and invade epithelial cell lines. The production of exopolysaccharide may contribute to the formation of biofilm and active efflux pumps promote resistance to antimicrobial agents such as bile salts and disinfectants. A holistic approach combining techniques such as comparative genome analysis, proteomics, and in vivo challenges could help unravel the complex interactions between this pathogen and its host. These data would help identify those properties in Cronobacter spp. which enable the bacterium to survive in the production environment and infect vulnerable neonates via the food chain.
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Affiliation(s)
- Brendan Healy
- Centres for Food Safety and Foodborne Zoonomics, School of Agriculture, Food Science, and Veterinary Medicine, University College Dublin, Belfield, Dublin, Ireland
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Outer membrane proteins A (OmpA) and X (OmpX) are essential for basolateral invasion of Cronobacter sakazakii. Appl Environ Microbiol 2010; 76:5188-98. [PMID: 20543055 DOI: 10.1128/aem.02498-09] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen that actively invades host eukaryotic cells. To identify invasion factors responsible for the intestinal translocation of C. sakazakii, we constructed for the first time outer membrane protein X (OmpX) and A (OmpA) deletion mutants using the lambda Red recombination system. The ompX and ompA deletion mutants showed significantly reduced invasion of human enterocyte-like epithelial Caco-2 and human intestinal epithelial INT-407 cells, and significantly fewer mutant cells were recovered from the livers and spleens of rat pups. Furthermore, compared with intact target cells, the invasion and initial association potentials of the mutants increased at a rate similar to that of the wild type in tight-junction-disrupted target cells, suggesting that OmpX and OmpA are involved in basolateral invasion by C. sakazakii. This is the first report of C. sakazakii virulence determinants that are essential for basolateral invasion and that may be critical for the virulence of C. sakazakii.
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Richardson AN, Beuchat LR, Lambert S, Williams D, Smith MA. Comparison of virulence of three strains of Cronobacter sakazakii in neonatal CD-1 mice. J Food Prot 2010; 73:849-54. [PMID: 20501035 DOI: 10.4315/0362-028x-73.5.849] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Cronobacter sakazakii (Enterobacter sakazakii) is an emerging pathogen that has been isolated from powdered infant formula and associated with outbreaks of infection in infants in neonatal intensive care units. In a previous study, we observed that neonatal CD-1 mice are susceptible to C. sakazakii infection and that the pathogen invades brain, liver, and cecum tissues. The study objective was to compare the virulence of three strains of C. sakazakii in neonatal CD-1 mice. The strains tested were MNW2 (a food isolate), SK81 (a clinical isolate), and 3290 (a clinical isolate). Timed-pregnant CD-1 mice were allowed to give birth on gestation day 19 or 20. Neonatal mice were sexed and culled to 10 per litter, each having five males and five females. Neonates were orally gavaged with C. sakazakii strains MNW2, SK81, or 3290 at doses ranging from 10(2.8) to 10(10.5) CFU on postnatal day 3.5. Pups surviving to postnatal day 10.5 were euthanized, and brain, liver, and cecum tissues were excised. C. sakazakii was isolated from all three tissues in mice treated with C. sakazakii, regardless of strain. C. sakazakii strain 3290 was significantly more invasive in brains (42.1% of mice) than were strains MNW2 (6.7%) and SK81 (15.9%). Mortality was observed for all strains of C. sakazakii tested, with SK81 being significantly more lethal (5.6%) than MNW2 (1.2%) or 3290 (0.6%). Our findings suggest that invasiveness does not necessarily correlate with mortality among different strains of C. sakazakii, and the clinical isolates are more virulent than the food isolate.
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Affiliation(s)
- Arena N Richardson
- Department of Environmental Health Science, 206 Environmental Health Science Building, University of Georgia, Athens, Georgia 30602-2102, USA
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Mittal R, Bulgheresi S, Emami C, Prasadarao NV. Enterobacter sakazakii targets DC-SIGN to induce immunosuppressive responses in dendritic cells by modulating MAPKs. THE JOURNAL OF IMMUNOLOGY 2009; 183:6588-99. [PMID: 19846880 DOI: 10.4049/jimmunol.0902029] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Enterobacter sakazakii (ES) is an emerging pathogen that causes meningitis and necrotizing enterocolitis in infants. Dendritic cells (DCs) are professional phagocytic cells that play an essential role in host defense against invading pathogens; however, the interaction of ES with DCs is not known. In this study, we demonstrate that ES targets DC-specific ICAM nonintegrin (DC-SIGN) to survive in myeloid DCs for which outer membrane protein A (OmpA) expression in ES is critical, although it is not required for uptake. In addition, DC-SIGN expression was sufficient to cause a significant invasion by ES in HeLa cells and intestinal epithelial cells, which are normally not invaded by ES. OmpA(+) ES prevented the maturation of DCs by triggering the production of high levels of IL-10 and TGF-beta and by suppressing the activation of MAPKs. Pretreatment of DCs with Abs to IL-10 and TGF-beta or of bacteria with anti-OmpA Abs significantly enhanced the maturation markers on DCs. Furthermore, DCs pretreated with various inhibitors of MAPKs prohibited the increased production of proinflammatory cytokines stimulated by LPS or OmpA(-) ES. LPS pretreatment followed by OmpA(+) ES infection of DCs failed to induce maturation of DCs, indicating that OmpA(+) ES renders the cells in immunosuppressive state to external stimuli. Similarly, OmpA(+) ES-infected DCs failed to present Ag to T cells as indicated by the inability of T cells to proliferate in MLR. We conclude that ES interacts with DC-SIGN to subvert the host immune responses by disarming MAPK pathway in DCs.
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Affiliation(s)
- Rahul Mittal
- Division of Infectious Diseases, Childrens Hospital Los Angeles, Los Angeles, CA 90027, USA
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