scholarly journals Chemotaxis and Shorter O-Antigen Chain Length Contribute to the Strong Desiccation Tolerance of a Food-Isolated Cronobacter sakazakii Strain

2022 ◽  
Vol 12 ◽  
Author(s):  
Chengqian Qian ◽  
Min Huang ◽  
Yuhui Du ◽  
Jingjie Song ◽  
Huiqian Mu ◽  
...  
Keyword(s):  
Chain Length ◽  
Desiccation Tolerance ◽  
Opportunistic Pathogen ◽  
Neonatal Meningitis ◽  
Powdered Infant Formula ◽  
Cronobacter Sakazakii ◽  
Protein Levels ◽  
O Antigen ◽  
Adaptation Mechanisms

Cronobacter sakazakii is an opportunistic pathogen causing a lethality rate as high as 80% in infants. Desiccation tolerance ensures its survival in powdered infant formula (PIF) and contributes to the increased exposure to neonates, resulting in neonatal meningitis, septicemia, and necrotizing enterocolitis. This study showed that a food-isolated C. sakazakii G4023 strain exhibited a stronger desiccation tolerance than C. sakazakii ATCC 29544 strain. Considering the proven pathogenicity of G4023, it could be a big threat to infants. Transcriptome and proteome were performed to provide new insights into the desiccation adaptation mechanisms of G4023. Integrated analyses of these omics suggested that 331 genes were found regulated at both transcriptional and protein levels (≥2.0- and ≥1.5-fold, respectively). Deletion of chemotaxis system encoded genes cheA and cheW resulted in decreased tolerance in both short- and long-term desiccation. Reduced O-antigen chain length contributed to the biofilm formation and desiccation tolerance in the short term rather than the long term. In addition, biosynthesis of flagella, arginine and its transport system, and Fe/S cluster were also observed regulated in desiccated G4023. A better understanding of desiccation adaptation mechanisms of G4023 could in turn guide the operations during production and preservation of PIF or other food to reduce survival odds of G4023 and lower its exposure to get to infants.

Genetic Diversity of Cronobacter sakazakii Isolates Collected from a Swiss Infant Formula Production Facility

2013 ◽  
Vol 76 (5) ◽  
pp. 883-887 ◽  
Author(s):  
ANDREA MÜLLER ◽  
ROGER STEPHAN ◽  
CLAUDIA FRICKER-FEER ◽  
ANGELIKA LEHNER
Keyword(s):  
Infant Formula ◽  
Monitoring Program ◽  
Sequence Type ◽  
Powdered Infant Formula ◽  
Cronobacter Sakazakii ◽  
Production Facility ◽  
Pfge Analysis ◽  
O Antigen ◽  
Selection For ◽  
Prevalent Species

In this study, 141 Cronobacter isolates that were collected based on a hygienic monitoring program performed in a powdered infant formula production facility in Switzerland between September 2011 and October 2012 were further characterized. Isolates were identified to the species level by molecular methods, and strains of Cronobacter sakazakii were further subtyped by applying PCR-based O-antigen serotyping, multilocus sequence typing (MLST), and pulsed-field gel electrophoresis (PFGE). C. sakazakii was the most prevalent species identified (93.6%). Among this collection of isolates, representatives of all but one O-antigen serotype (serotype O5) were recognized. MLST analysis of 19 selected isolates revealed that most of the typeable isolates belonged to sequence type (ST) 4. Correlations between ST4 and serotype O2 and between ST83 and serotype O7 were observed. PFGE analysis revealed clusters with multiple isolates, including strains from samples collected at different time points and sampling sources. Generally, the observed heterogeneity among strains collected over the 13 months of the monitoring program was high, suggesting a constant flux among strains rather than a selection for persisting organisms.

Alterations in the transcriptional landscape allows differential desiccation tolerance in different strains of Cronobacter sakazakii

2021 ◽  
Author(s):  
Yu Cao ◽  
Katherine Dever ◽  
Sathesh Kumar Sivasankaran ◽  
Scott V. Nguyen ◽  
Guerrino Macori ◽  
...  
Keyword(s):  
Infant Formula ◽  
Desiccation Tolerance ◽  
Growth Conditions ◽  
Evolutionary Strategies ◽  
Clinical Strain ◽  
Powdered Infant Formula ◽  
Cronobacter Sakazakii ◽  
Rna Seq ◽  
Environmental Strain ◽  
Different Strains

Cronobacter sakazakii is a typical example of a xerotolerant bacterium. It is epidemiologically linked to low moisture foods like powdered infant formula (PIF) and is associated with high fatality rates among neonates. We characterized the xerotolerance in a clinically isolated strain, C. sakazakii ATCC™29544 T , and compared the desiccation tolerance with an environmental strain, C. sakazakii SP291, whose desiccation tolerance was previously characterized. We found that, although the clinical strain was desiccation-tolerant, the level of tolerance was compromised when compared to the environmental strain. RNA-seq based deep transcriptomic characterization identified a unique transcriptional profile in the clinical strain compared to what was already known for the environmental strain. As RNA-seq was also carried out in different TSB growth conditions, genes that were expressed specifically under desiccated conditions were identified and denoted as desiccation responsive genes (DRGs). Interestingly, these DRGs included transcriptomic factors like fnr , ramA, and genes associated with inositol metabolism, a phenotype as yet unreported in C. sakazakii . Further, the clinical strain did not express the proP gene, which was previously reported to be very important for desiccation survival and persistence. Interestingly, analysis of the plasmid genes showed that the iron metabolism in desiccated C. sakazakii ATCC™29544 T cells specifically involved the siderophore cronobactin encoded by the iucABCD genes. Confirmatory studies using qRT-PCR determined that, though the secondary desiccation response genes were upregulated in C. sakazakii ATCC™29544 T , the level of up-regulation was lower compared to that in C. sakazakii SP291. All these factors could collectively contribute to the compromised desiccation tolerance in the clinical strain. IMPORTANCE Cronobacter sakazakii has in past led to outbreaks, particularly associated with food that are low in moisture content. This species has adapted to survive in low water conditions and can survive in such environments for long periods. These characteristics have enabled the pathogen to contaminate powder infant formula, a food matrix with which the pathogen has been epidemiologically associated. Even though clinically adapted strains can also be isolated, there is no information on how the clinical strains adapt to low moisture environments. Our research assessed the adaptation of a clinically isolated strain to low moisture survival on sterile stainless steel coupons and compared the survival to a highly desiccation-tolerant environmental strain. We found that, even though the clinical strain is desiccation-tolerant, the rate of tolerance was compromised compared to the environmental strain. A deeper investigation using RNA-seq identified that the clinical strain used pathways different from that of the environmental strain to adapt to low moisture conditions. This shows that the adaptation to desiccation conditions, at least for C. sakazakii , is strain-specific and that different strains have used different evolutionary strategies for adaptation.

scholarly journals Putative Inv Is Essential for Basolateral Invasion of Caco-2 Cells and Acts Synergistically with OmpA To AffectIn VitroandIn VivoVirulence of Cronobacter sakazakii ATCC 29544

2014 ◽  
Vol 82 (5) ◽  
pp. 1755-1765 ◽  
Author(s):  
Dilini Chandrapala ◽  
Kyumson Kim ◽  
Younho Choi ◽  
Amal Senevirathne ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Outer Membrane Proteins ◽  
Opportunistic Pathogen ◽  
Additive Effect ◽  
Neonatal Meningitis ◽  
Cronobacter Sakazakii ◽  
Content Type ◽  
Enteric Infections ◽  
Culture Models

ABSTRACTCronobacter sakazakiiis an opportunistic pathogen that causes neonatal meningitis and necrotizing enterocolitis. Its interaction with intestinal epithelium is important in the pathogenesis of enteric infections. In this study, we investigated the involvement of theinvgene in the virulence ofC. sakazakiiATCC 29544in vitroandin vivo. Sequence analysis ofC. sakazakiiATCC 29544invrevealed that it is different from otherC. sakazakiiisolates. In various cell culture models, an Δinvdeletion mutant showed significantly lowered invasion efficiency, which was restored upon genetic complementation. Studying invasion potentials using tight-junction-disrupted Caco-2 cells suggested that theinvgene product mediates basolateral invasion ofC. sakazakiiATCC 29544. In addition, comparison of invasion potentials of double mutant (ΔompA Δinv) and single mutants (ΔompAand Δinv) provided evidence for an additive effect of the two putative outer membrane proteins. Finally, the importance ofinvand the additive effect of putative Inv and OmpA were also proven in anin vivorat pup model. This report is the first to demonstrate two proteins working synergisticallyin vitro, as well asin vivoinC. sakazakiipathogenesis.

Neonatal Mice as Models for Cronobacter sakazakii Infection in Infants

2009 ◽  
Vol 72 (11) ◽  
pp. 2363-2367 ◽  
Author(s):  
ARENA N. RICHARDSON ◽  
SONYA LAMBERT ◽  
MARY ALICE SMITH
Keyword(s):  
Total Dose ◽  
Infant Formula ◽  
Mouse Strain ◽  
Lethal Dose ◽  
Opportunistic Pathogen ◽  
Mouse Strains ◽  
Powdered Infant Formula ◽  
Infant Formulas ◽  
Cronobacter Sakazakii ◽  
Infectious Dose

Cronobacter sakazakii is an opportunistic pathogen that has been isolated from powdered infant formulas. C. sakazakii infection can result in serious illnesses such as bacteremia, septicemia, meningitis, and death in at-risk infants who are orally fed contaminated reconstituted powdered infant formulas. The objective of this study was to compare the susceptibilities of BALB/c, C57BL/6, and CD-1 mice to C. sakazakii strain MNW2. We acquired timed-pregnant CD-1 mice and allowed them to give birth naturally. On postnatal day 3.5, each pup was administered a total dose of approximately 102 to 1011 CFU C. sakazakii strain MNW2 in reconstituted powdered infant formula. Mice were observed twice daily for morbidity and mortality. At postnatal day 10.5, the remaining pups were euthanized, and brain, liver, and cecum were excised and analyzed for the presence of C. sakazakii. C. sakazakii was isolated from brains, livers, and ceca in all three mouse strains. The CD-1 mouse strain was the most susceptible of the three, with the lowest infectious dose (102 CFU) and the lowest lethal dose (also 102 CFU).

scholarly journals Development of an O-Antigen Serotyping Scheme forCronobacter sakazakii

2011 ◽  
Vol 77 (7) ◽  
pp. 2209-2214 ◽  
Author(s):  
Yamin Sun ◽  
Min Wang ◽  
Hongbo Liu ◽  
Jingjing Wang ◽  
Xin He ◽  
...  
Keyword(s):  
Fragment Length Polymorphism ◽  
Gene Clusters ◽  
Opportunistic Pathogen ◽  
Cronobacter Sakazakii ◽  
Bacterial Strains ◽  
Banding Patterns ◽  
O Antigen ◽  
Severe Infections ◽  
O Antigens ◽  
Restriction Fragment Length

ABSTRACTCronobacter sakazakiiis an opportunistic pathogen that can cause severe infections. Serotyping provides a basis for the categorization of bacterial strains and is an important tool for epidemiological and surveillance purposes. In this study, of the 135Cronobacterstrains tested initially, 119 were identified asC. sakazakiiand used. A serotyping scheme forC. sakazakiithat classifies strains based on their different O antigens was developed. Seven antisera that exhibited high agglutinin titers (>640) were produced. O2 and O6 antisera were specific for their homologous strains, O4 and O7 antisera gave heterologous titers with O1 and O6 antigens, respectively, and O1, O3, and O5 antisera cross-reacted with each other and require preabsorption with the other two antigens. All of these 119C. sakazakiistrains were clearly assigned to these seven serotypes. O1 and O2 are the dominant serotypes, comprising 69.7% of the isolates. We also characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP). The grouping ofC. sakazakiistrains based on their RFLP banding patterns correlated well with the grouping of strains based on our serotyping scheme. The serotype scheme presented here could prove to be a useful tool for serotypingC. sakazakiiisolates.

scholarly journals Remodeling of O Antigen in MucoidPseudomonas aeruginosavia Transcriptional Repression ofwzz2

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ashley R. Cross ◽  
Joanna B. Goldberg
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Chain Length ◽  
Transcriptional Repression ◽  
Antigen Expression ◽  
Opportunistic Pathogen ◽  
Negative Regulator ◽  
Content Type ◽  
O Antigen ◽  
Alginate Production

ABSTRACTPseudomonas aeruginosais an opportunistic pathogen that causes chronic lung infections in people with cystic fibrosis (CF). ChronicP. aeruginosaisolates generally do not express O antigen and often have a mucoid phenotype, which is characterized by the overproduction of the exopolysaccharide alginate. Therefore, O antigen expression and the mucoid phenotype may be coordinately regulated upon chronic adaption to the CF lung. Here we demonstrate that PDO300, a mucoid strain derived from the nonmucoid laboratory isolate PAO1, does not produce very long O antigen due to decreased expression of Wzz2, the very long O antigen chain length control protein, and that mucoid clinical isolates express reduced levels of Wzz2 compared to nonmucoid isolates. Further, we show that forcing the expression of very long O antigen by PDO300, by providingwzz2intrans, does not alter alginate production, suggesting that sugar precursors are not limited between the two biosynthesis pathways. Moreover, we confirm that AmrZ, a transcription factor highly expressed in mucoid strains, is a negative regulator ofwzz2promoter activity and very long O antigen expression. These experiments identify the first transcriptional regulator of O antigen chain length inP. aeruginosaand support a model where transition to a chronic mucoid phenotype is correlated with downregulation of very long O antigen through decreased Wzz2 production.IMPORTANCEDetection of mucoidPseudomonas aeruginosa, characterized by the overproduction of alginate, is correlated with the establishment of a chronic pulmonary infection and disease progression in people with cystic fibrosis (CF). In addition to the overproduction of alginate, loss of O antigen lipopolysaccharide production is also selected for in chronic infection isolates. In this study, we have identified the regulatory network that inversely regulates O antigen and alginate production. Understanding the regulation of these chronic phenotypes will elucidate mechanisms that are important for the establishment of a long-termP. aeruginosalung infection and ultimately provide an opportunity for intervention. PreventingP. aeruginosafrom chronically adapting to the CF lung environment could provide a better outcome for people who are infected.

scholarly journals Genotyping and Source Tracking of Cronobacter sakazakii and C. malonaticus Isolates from Powdered Infant Formula and an Infant Formula Production Factory in China

2015 ◽  
Vol 81 (16) ◽  
pp. 5430-5439 ◽  
Author(s):  
Peng Fei ◽  
Chaoxin Man ◽  
Binbin Lou ◽  
Stephen J. Forsythe ◽  
Yunlei Chai ◽  
...  
Keyword(s):  
Infant Formula ◽  
Source Tracking ◽  
Neonatal Meningitis ◽  
Powdered Infant Formula ◽  
Cronobacter Sakazakii ◽  
Sequence Analyses ◽  
Content Type ◽  
Fluidized Bed Drying ◽  
Contamination Routes ◽  
Sequence Types

ABSTRACTCronobacterspp. (formerly defined asEnterobacter sakazakii) are opportunistic bacterial pathogens of both infants and adults. In this study, we analyzed 70Cronobacterisolates 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, andompAandrpoBsequence analyses. The isolates were primarilyCronobacter sakazakii(66/70) orCronobactermalonaticus(4/70). The strains were divided into 38 pulsotypes (PTs) using PFGE and 19 sequence types (STs) by MLST. In contrast,rpoBandompAsequence analyses divided the strains into 10 overlapping clusters each. PCR serotyping of the 66C. sakazakiiand 4C. malonaticusstrains resulted in the identification of fourC. sakazakiiserotypes (O1, O2, O4, and O7) and a singleC. malonaticusserotype, O2. The dominantC. sakazakiisequence types from PIF and an infant formula production factory in China wereC. sakazakiiclonal complex 4 (CC4) (n= 19), ST1 (n= 14), and ST64 (n= 11).C. sakazakiiCC4 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 withCronobactercontamination.C. sakazakiistrains 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.

Comparison of Desiccation Tolerance among Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica, and Cronobacter sakazakii in Powdered Infant Formula

2015 ◽  
Vol 78 (1) ◽  
pp. 104-110 ◽  
Author(s):  
SHIGENOBU KOSEKI ◽  
NOBUTAKA NAKAMURA ◽  
TAKEO SHIINA
Keyword(s):  
Desiccation Tolerance ◽  
Storage Temperature ◽  
Bacterial Pathogens ◽  
Weibull Model ◽  
Escherichia Coli O157 ◽  
Powdered Infant Formula ◽  
Cronobacter Sakazakii ◽  
Bacterial Inactivation ◽  
E Coli ◽  
Kinetics Of

Bacterial pathogens such as Listeria monocytogenes, Escherichia coli O157:H7, Salmonella enterica, and Cronobacter sakazakii have demonstrated long-term survival in/on dry or low–water activity (aw) foods. However, there have been few comparative studies on the desiccation tolerance among these bacterial pathogens separately in a same food matrix. In the present study, the survival kinetics of the four bacterial pathogens separately inoculated onto powdered infant formula as a model low-aw food was compared during storage at 5, 22, and 35°C. No significant differences in the survival kinetics between E. coli O157:H7 and L. monocytogenes were observed. Salmonella showed significantly higher desiccation tolerance than these pathogens, and C. sakazakii demonstrated significantly higher desiccation tolerance than all other three bacteria studied. Thus, the desiccation tolerance was represented as C. sakazakii > Salmonella > E. coli O157:H7 = L. monocytogenes. The survival kinetics of each bacterium was mathematically analyzed, and the observed kinetics was successfully described using the Weibull model. To evaluate the variability of the inactivation kinetics of the tested bacterial pathogens, the Monte Carlo simulation was performed using assumed probability distribution of the estimated fitted parameters. The simulation results showed that the storage temperature significantly influenced survival of each bacterium under the dry environment, where the bacterial inactivation became faster with increasing storage temperature. Furthermore, the fitted rate and shape parameters of the Weibull model were successfully modelled as a function of temperature. The numerical simulation of the bacterial inactivation was realized using the functions of the parameters under arbitrary fluctuating temperature conditions.

scholarly journals Neonatal Ureaplasma parvum meningitis complicated with subdural hematoma: a case report and literature review

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Canyang Zhan ◽  
Lihua Chen ◽  
Lingling Hu
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Subdural Hematoma ◽  
Central Nervous System Infection ◽  
Neonatal Meningitis ◽  
High Morbidity ◽  
Ureaplasma Parvum ◽  
Protein Levels ◽  
Csf Analysis ◽  
Empirical Antibiotics

Abstract Background Neonatal meningitis is a severe infectious disease of the central nervous system with high morbidity and mortality. Ureaplasma parvum is extremely rare in neonatal central nervous system infection. Case presentation We herein report a case of U. parvum meningitis in a full-term neonate who presented with fever and seizure complicated with subdural hematoma. After hematoma evacuation, the seizure disappeared, though the fever remained. Cerebrospinal fluid (CSF) analysis showed inflammation with CSF pleocytosis (1135–1319 leukocytes/μl, mainly lymphocytes), elevated CSF protein levels (1.36–2.259 g/l) and decreased CSF glucose (0.45–1.21 mmol/l). However, no bacterial or viral pathogens in either CSF or blood were detected by routine culture or serology. Additionally, PCR for enteroviruses and herpes simplex virus was negative. Furthermore, the CSF findings did not improve with empirical antibiotics, and the baby experienced repeated fever. Thus, we performed metagenomic next-generation sequencing (mNGS) to identify the etiology of the infection. U. parvum was identified by mNGS in CSF samples and confirmed by culture incubation on mycoplasma identification medium. The patient’s condition improved after treatment with erythromycin for approximately 5 weeks. Conclusions Considering the difficulty of etiological diagnosis in neonatal U. parvum meningitis, mNGS might offer a new strategy for diagnosing neurological infections.

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