FEMS MICROBIOLOGY LETTERS
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2015
·Vol. 362
·期 6
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IF 2.121
Zhao Jianqing,Pan Shan,Lin Lan,Fu Lei,Yang Chao,Xu Zhongmin,Wei YanMin,Jin Meilin,Zhang Anding
Streptococcus suis (S. suis) ranks among the five most important porcine pathogens worldwide and occasionally threatens human health, especially in people that come into close contact with pigs or pork products. Streptococcus suis serotype 2 (SS2) is considered to be the most pathogenic and prevalent capsular type. As a first line of immune defense against SS2 infection, neutrophils can eliminate the invader not only by phagocytosis but also by neutrophil extracellular traps (NETs)-mediated killing. SS2 can resist phagocytosis through polysaccharide capsule (CPS), but how this strain evades the effects of NETs remains to be determined. The present study demonstrated that the epidemic strain 05ZY, the highly pathogenic strain P1/7 and the intermediately pathogenic strain A7 could induce the formation of NETs. Furthermore, SS2 strains could successfully resist NETs-mediated killing, and the CPS structure contributed to this resistance by escaping the trapping. Therefore, the CPS structure not only contributed to the SS2 strains’ resistance to phagocytosis-mediated killing but also played an essential role in evading NETs trapping and further killing in vitro. This study strengthens our understanding of how S. suis can evade innate immune surveillance and elimination.
研究领域:
微生物学
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免疫学
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高影响因子
APPLIED SOIL ECOLOGY
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2025
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IF 5
Dan Yu,Fangmin Chen,Jinliang Deng,Zhe Pu,Xinyao Yang
The presence of biocidal compounds in the rhizosphere complicates the prediction of bacterial fate and transport in soil. This study investigated how phloretin, a plant-derived biocide, alters the mobility of Salmonella typhimurium and Salmonella enteritidis in soil by inducing structural adaptations in bacterial membranes. Phloretin exposure triggered consistent changes in physicochemical properties of both serovars (e.g., increasing zeta potential and decreasing hydrophobicity). Despite these shared trends, mobility responses diverged markedly. Following adaption at Minimal Inhibition Concentration of phloretin, S. enteritidis showed an increasing deposition rate from 0.17 to 1.68, while S. typhimurium showed a decreasing deposition rate from 0.18 to 0.14. These contrasting outcomes suggest that electrostatic and hydrophobic interactions alone could not explain the observed mobility patterns. Alternatively, membrane characterization results suggest that serovar-specific structural remodeling of lipopolysaccharide (LPS) may be responsible for the divergent behaviors. Phloretin induced an elongation of LPS chains by about 30 % in S. enteritidis , promoting adhesion and immobilization, while S. typhimurium retained shorter LPS structures, reducing adhesion and facilitating transport. Since LPS also constitutes a protective layer against harsh environment, the observed inverse link between LPS length and mobility thusly underscores a trade-off between bacterial endurance and dissemination. Furthermore, the finding that lower mobility of S. enteritidis occurring under higher biocidal stress implies higher pathogen accumulation closer to the root surfaces, where the biocidal levels are higher, thereby amplifying localized antimicrobial efficacy. The insights gained are useful in prediction of pathogen risks in the rhizosphere.
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Frontiers in Microbiology
·
2019
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IF 4.259
Chi Xiaohui,Berglund Björn,Zou Huiyun,Zheng Beiwen,Börjesson Stefan,Ji Xiang,Ottoson Jakob,Lundborg Cecilia Stålsby,Li Xuewen,Nilsson Lennart E.
Klebsiella pneumoniae is a gram-negative, opportunistic pathogen, and a common cause of healthcare-associated infections such as pneumonia, septicemia, and urinary tract infection. The purpose of this study was to survey the occurrence of and characterize K. pneumoniae in different environmental sources in a rural area of Shandong province, China. Two hundred and thirty-one samples from different environmental sources in 12 villages were screened for extended-spectrum β-lactamase-(ESBL)-producing K. pneumoniae, and 14 (6%) samples were positive. All isolates were multidrug-resistant and a few of them belonged to clinically relevant strains which are known to cause hospital outbreaks worldwide. Serotypes, virulence genes, serum survival, and phagocytosis survival were analyzed and the results showed the presence of virulence factors associated with highly virulent clones and a high degree of phagocytosis survivability, indicating the potential virulence of these isolates. These results emphasize the need for further studies designed to elucidate the role of the environment in transmission and dissemination of ESBL-producing K. pneumoniae and the potential risk posed to human and environmental health.
研究领域:
微生物学
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传染病学
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环境卫生
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公共卫生
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分子生物学
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Foods
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2025
·Vol. 14
·期 14
·2481
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IF 5.1
Wei Yan,Liping Chen,Lei Ji,Rui Yuan,Fenfen Dong,Peng Zhang
Vibrio parahaemolyticusis the leading bacterial cause of gastroenteritis associated with aquatic food consumption globally. This study aimed to determine the prevalence ofV. parahaemolyticusin aquatic foods from Huzhou and to identify the serotypes, antimicrobial resistance, virulence factors, and genetic relatedness of the strains. A total of 306 isolates were detected from 1314 aquatic food samples from 2022 to 2024. The results indicated that the most prevalent serotypes were O1:KUT (17.0%), O2:K28 (13.7%), and O2:KUT (13.1%). Multilocus sequence typing analysis divided the 306 isolates into 175 sequence types (STs), and the predominant sequence type was ST864 (3.3%). Antimicrobial susceptibility tests showed that 2.6% of isolates were multidrug resistant. High resistance was observed to ampicillin (64.7%) and streptomycin (44.4%). A total of seven antimicrobial categories of resistance genes were identified, and the resistance geneblaCARBwas detected in all isolates. The virulence genestdhandtrhwere found in 16 (5.2%) and 12 (3.9%) isolates, respectively. In addition, we observed that all the 306V. parahaemolyticusisolates encode type III secretion systems 1. The phylogenomic analysis based on the whole-genome sequence revealed that the 306 isolates were divided into four clusters. Our findings broaden perspectives onV. parahaemolyticusgenetic diversity and enhance our ability to assess the potential risks of its spread.
研究领域:
微生物学
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食品安全
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基因组学
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流行病学
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抗菌素耐药性
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分子生物学
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JOURNAL OF VIROLOGY
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2023
·Vol. 97
·期 5
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IF 5.4
Renrong You,Kangchengyin Liu,Min Huang,Lihua Tang,Xuehui Zhang,Yahui Huang,Jing Zhao,Ye Zhao,Lilin Ye,Guozhong Zhang
Infectious bronchitis virus (IBV) infections are initiated by the transmembrane spike (S) glycoprotein, which binds to host factors and fuses the viral and cell membranes. The N-terminal domain of the S1 subunit of IBV S protein binds to sialic acids, but the precise location of the sialic acid binding domain (SABD) and the role of the SABD in IBV-infected chickens remain unclear. Here, we identify the S1 N-terminal amino acid (aa) residues 19 to 227 (209 aa total) of IBV strains SD (GI-19) and GD (GI-7), and the corresponding region of M41 (GI-1), as the minimal SABD using truncated protein histochemistry and neuraminidase assays. Both α-2,3- and α-2,6-linked sialic acids on the surfaces of CEK cells can be used as attachment receptors by IBV, leading to increased infection efficiency. However, 9-O acetylation of the sialic acid glycerol side chain inhibits IBV S1 and SABD protein binding. We further constructed recombinant strains in which the S1 gene or the SABD in the GD and SD genomes were replaced with the corresponding region from M41 by reverse genetics. Infecting chickens with these viruses revealed that the virulence and nephrotropism of rSDM41-S1, rSDM41-206, rGDM41-S1, and rGDM41-206 strains were decreased to various degrees compared to their parental strains. A positive sera cross-neutralization test showed that the serotypes were changed for the recombinant viruses. Our results provide insight into IBV infection of host cells that may aid vaccine design.IMPORTANCE To date, only α-2,3-linked sialic acid has been identified as a potential host binding receptor for IBV. Here, we show the minimum region constituting the sialic acid binding domain (SABD) and the binding characteristics of the S1 subunit of spike (S) protein of IBV strains SD (GI-19), GD (GI-7), and M41 (GI-1) to various sialic acids. The 9-O acetylation modification partially inhibits IBV from binding to sialic acid, while the virus can also bind to sialic acid molecules linked to host cells through an α-2,6 linkage, serving as another receptor determinant. Substitution of the putative SABD from strain M41 into strains SD and GD resulted in reduced virulence, nephrotropism, and a serotype switch. These findings suggest that sialic acid binding has diversified during the evolution of γ-coronaviruses, impacting the biological properties of IBV strains. Our results offer insight into the mechanisms by which IBV invades host cells.
研究领域:
病毒学
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分子生物学
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免疫学
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动物健康
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PubMed
高影响因子
ANALYTICA CHIMICA ACTA
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2022
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IF 6.911
Yarong Ren,Juan Wei,Ye Wang,Peng Wang,Yanwei Ji,Baoyuan Liu,Jianlong Wang,Gualberto González-Sapienza,Yanru Wang
Salmonella are major pathogens that cause foodborne diseases. In this work, a broad-spectrum Salmonella nanobody-01 (Nb-01) was isolated and applied in the development of a streptavidin-bridged sandwich ELISA (SAB-ELISA) for simultaneously identifying five Salmonella serovars , including Salmonella Enteritidis ( S. Enteritidis), Salmonella Typhimurium ( S. Typhimurium), Salmonella London (S. London), Salmonella Paratyphi B (S. Paratyphi B) and Salmonella Hadar (S. Hadar). In this work, streptavidin (SA) was utilized as a scaffold to directionally immobilize biotinylated nanobody (BiNb) and Salmonella was detected by phage-displayed nanobodies. The SAB-ELISA can be accomplished within 180 min with a limit of detection (LOD) of 6.31 × 10 3 colony forming units (CFU) mL −1 , 9.15 × 10 3 CFU mL −1 , 4.23 × 10 3 CFU mL −1 , 7.31 × 10 3 CFU mL −1 and 7.25 × 10 3 CFU mL −1 towards S. Typhimurium, S. Enteritidis, S. London, S. Paratyphi B and S. Hadar, respectively. In comparison of sandwich ELISA by passive immobilization of Nb-01 on polystyrene plate, the sensitivity was increased by around 6-fold, which confirmed the enhanced immobilization efficacy of SAB-ELISA. Furthermore, the feasibility of the assay for S. Typhimurium determination in actual samples was evaluated, showing excellent recovery, inter-day and intra-day precision.
研究领域:
微生物学
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免疫学
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食品科学
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分子生物学
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高影响因子
FOOD RESEARCH INTERNATIONAL
·
2021
·
IF 6.475
Shang Wu,Yang Yang,Tingwei Wang,Jiadi Sun,Yinzhi Zhang,Jian Ji,Xiulan Sun
Antibiotic resistance in Salmonella enterica serovar Typhimurium ( S . ser. Typhimurium) has become a critical safety hazard in food. Sublethal environmental stresses can influence resistance in Salmonella during food processing. This study simulated environmental stresses in food processing. The antibiotic resistance of three strains of S . ser. Typhimurium (the ATCC 14028 strain and two wild-type isolates from chicken and pork product processing) was evaluated under different pH levels (5.0, 5.5, 6.0, 8.0, and 9.0). Also, dynamic changes in resistance with treatment duration under cold (4 °C, −20 °C) and heat (55 °C) treatment were studied. The results showed that acid and alkaline stresses reduced the resistance of S. ser. Typhimurium to eight antibiotics; meanwhile, the resistance of meropenem (MERO) increased. The minimal inhibitory concentration (MIC) of MERO was increased 16- to 64-fold. With acid or alkaline stress, the extracellular ATP content increased, and the scanning electron microscopy (SEM) result clearly revealed the appearance of wrinkles and holes on the outer membrane of Salmonella . These observations imply changes in membrane permeability, which may decrease the antibiotic resistance of Salmonella . Cold or heat stress increased the resistance of S . ser. Typhimurium to tetracycline, cefotaxime, ceftazidime, nalidixic acid, azithromycin, and ampicillin; the MIC increased 2- to 4-fold. The antibiotic resistance only changed when cold and heat stresses occurred over a certain period of time and remained unchanged when the stress persisted. This study reports on the ability of S. ser. Typhimurium to develop antibiotic resistance after environmental stresses. It can provide valuable information for meat processing to improve interventions and risk management.
研究领域:
微生物学
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食品科学
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抗菌素耐药性
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环境压力
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高影响因子
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