Live attenuated Salmonella Typhimurium with monophosphoryl lipid A retains ability to induce T-cell and humoral immune responses against heterologous polysaccharide of Shigella flexneri 2a.
In this study, we used recombinant attenuated Salmonella vaccine (RASV) strains to deliver Sf2a O-antigen and characterized the immune responses induced by the vectored O-antigen. First, we identified genes sufficient for biosynthesis of Sf2a O-antigen. A plasmid containing the identified genes was then introduced into the RASV strains, which were manipulated to produce only the heterologous O-antigen and modified lipid A. After oral immunization of mice, we demonstrated that RASV strains could induce potent humoral immune responses as well as robust CD4+ T-cell responses against Sf2a Lipopolysaccharide (LPS) and protect m...
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Liu Q, Su H, Bian X, Wang S, Kong Q Tags: Int J Med Microbiol Source Type: research

Molecular characterization of a carbon dioxide-dependent Escherichia coli small-colony variant isolated from blood cultures.
In conclusion, these data confirm that impaired carbonic anhydrase function can cause a carbon dioxide-dependent SCV phenotype in E. coli SH4888 and provides a fitness advantage in terms of infection. PMID: 32654769 [PubMed - in process] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Matsumoto T, Hashimoto M, Teng CH, Hsu PC, Ota Y, Takamizawa M, Kato R, Negishi T Tags: Int J Med Microbiol Source Type: research

Synthesis and anti-pseudomonal activity of new ß-Ala modified analogues of the antimicrobial peptide anoplin.
In this study, a series of new β-Ala modified-antimicrobial peptide analogues of anoplin were designed and synthesized, and their biological activities were described. Most of the new peptides showed perfect antimicrobial activities against two antibiotic-sensitive Pseudomonas aeruginosa strains and three clinical isolates of multidrug-resistant P. aeruginosa strains without significant hemolysis or cytotoxicity. More significantly, Ano-1β and Ano-8β (substituting positions 1 and 8 of anoplin with β-Ala, respectively) exhibited the best antimicrobial potency. Additionally, the two new peptides were stab...
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Zhong C, Zhu Y, Zhu N, Liu T, Gou S, Zhang F, Yao J, Xie J, Ni J Tags: Int J Med Microbiol Source Type: research

Transcriptional regulation of virulence factors Hla and phenol-soluble modulins α by AraC-type regulator Rbf in Staphylococcus aureus.
In this study, we revealed the new virulence-mediated role of Rbf that can negatively regulate the hemolytic activity. Furthermore, Rbf can specifically bind to the hla and psmα promoters to repress their expression, resulting in significantly decreased production of phenol-soluble modulins α (PSMα) and alpha-toxin. Accordingly, the rbf mutant strain exhibited the increased pathogenicity compared to the wild-type (WT) strain in a mouse subcutaneous abscess model, representing a type of acute infection by S. aureus. Collectively, our results provide a novel insight into the virulence regulation and acute i...
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Fang B, Liu B, Sun B Tags: Int J Med Microbiol Source Type: research

After Pettenkofer. Munich's Institute of Hygiene and the long shadow of National Socialism, 1894-1974.
z M Abstract The year 2019 marked the 140th anniversary of the inauguration of the first Institute of Hygiene, which was established for Max von Pettenkofer at the university of Munich. After Pettenkofer, his successors tried to advance the science of hygiene each in their own specific way, highlighting different aspects and trying to relate them to Pettenkofer's legacy: Max von Gruber promoted an understanding of hygiene which was more and more tied to constitutional and racial factors, Karl Kisskalt tried to revise a perceived bacteriological paradigm, and Hermann Eyer focused on preventive public health measure...
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Schütz M Tags: Int J Med Microbiol Source Type: research

Exploring the antibacterial mechanism of essential oils by membrane permeability, apoptosis and biofilm formation combination with proteomics analysis against methicillin-resistant staphylococcus aureus.
Abstract Methicillin-resistant Staphylococcus aureus (MRSA) is one of the important causes of food poisoning and infectious diseases worldwide, it can produce a large number of virulence factors, enhance the colonization ability of the host so that it can quickly colonize and spread on the surface of the objects. Essential oil (EO) is one of the natural products with antimicrobial properties, can be used as an important source of antibacterial agent discovery, and has a broad development prospect. However, the unclear mechanisms of antibacterial action have become an obstacle to its further development and use. He...
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Tang C, Chen J, Zhang L, Zhang R, Zhang S, Ye S, Zhao Z, Yang D Tags: Int J Med Microbiol Source Type: research

Immunostimulatory efficacy and protective potential of putative TgERK7 protein in mice experimentally infected by Toxoplasma gondii.
The objective of this study was to produce a recombinant TgERK7 protein in vitro and to evaluate its effect on the induction of humoral and T cell-mediated immune responses against T. gondii infection in BALB/c mice. Immunization using TgERK7 mixed with Freund's adjuvants significantly increased the ratio of CD3e+CD4+ T/CD3e+CD8a+ T lymphocytes in spleen and elevated serum cytokines (IFN-γ, IL-2, IL-4, IL-10, IL-12p70, IL-23, MCP-1, and TNF-α) in immunized mice compared to control mice. On the contrary, immunization did not induce high levels of serum IgG antibodies. Five predicted peptides of TgERK7 were synth...
Source: International Journal of Medical Microbiology - July 1, 2020 Category: Microbiology Authors: Li ZY, Guo HT, Calderón-Mantilla G, He JJ, Wang JL, Bonev BB, Zhu XQ, Elsheikha HM Tags: Int J Med Microbiol Source Type: research

Myo-Inositol as a carbon substrate in Francisella and insights into the metabolism of Francisella sp. strain W12-1067.
r K Abstract Recently, a new environmental Francisella strain, Francisella sp. strain W12-1067, has been identified in Germany. This strain is negative for the Francisella pathogenicity island (FPI) but exhibits a putative alternative type VI secretion system. Some known virulence factors of Francisella are present, but the pathogenic capacity of this species is not known yet. In silico genome analysis reveals the presence of a gene cluster tentatively enabling myo-inositol (MI) utilization via a putative inositol oxygenase. Labelling experiments starting from 2H-inositol demonstrate that this gene cluster is inde...
Source: International Journal of Medical Microbiology - May 5, 2020 Category: Microbiology Authors: Chen F, Köppen K, Rydzewski K, Einenkel R, Morguet C, Vu DT, Eisenreich W, Heuner K Tags: Int J Med Microbiol Source Type: research

Microbiota and cancer: host cellular mechanisms activated by gut microbial metabolites.
Abstract In recent years, more and more data indicate the effect of human microbiota on carcinogenesis. Despite the numerous studies on the relationship between gut microbiota and carcinogenesis, the exact mechanisms of this interaction are not well studied. It becomes apparent that this relationship can be mediated by microbial metabolites. Mechanisms of some well-known bacterial genotoxins and oncogenes, such as colibactin, CagA, IpgD, VirA, P37, have been studied in detail. At the same time, a role in carcinogenesis of a large group of gut microbial metabolites, including short-chain fatty acids, polyamines, an...
Source: International Journal of Medical Microbiology - April 24, 2020 Category: Microbiology Authors: Tsvetikova SA, Koshel EI Tags: Int J Med Microbiol Source Type: research

Pathogenomics insights for understanding Pasteurella multocida adaptation.
This article is the first review describing the genomic relationship to elucidate the diversity and evolution of P. multocida. PMID: 32276876 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - March 25, 2020 Category: Microbiology Authors: Hurtado R, Maturrano L, Azevedo V, Aburjaile F Tags: Int J Med Microbiol Source Type: research

Novel role of the phosphatidylinositol phosphatase Sac1 in membrane homeostasis and polarized growth in Candida albicans.
This study revealed that the PIPase CaSac1 plays an essential role in regulating membrane homeostasis and membrane traffic, contributing to establishment of polarized hyphal growth. PMID: 32245626 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - March 24, 2020 Category: Microbiology Authors: Zhang B, Peng L, Zhu N, Yu Q, Li M Tags: Int J Med Microbiol Source Type: research

The Treponema pallidum outer membrane protein Tp92 activates endothelial cells via the chemerin/CMKLR1 pathway.
In this study, we investigated the effect of Tp92 on endothelial cells activation. The data showed that Tp92 induced chemerin production in activated endothelial cells. Endothelial cell-derived chemerin upregulated the expression of TNF-α and ICAM-1 in endothelial cells via CMKLR1. In addition, endothelial cell-derived chemerin promoted THP-1-derived macrophage migration towards endothelial cells. These findings suggest that Tp92 may play an important role in mediating endothelial cell activation by inducing the secretion of chemerin. PMID: 32173267 [PubMed - as supplied by publisher] (Source: International Jour...
Source: International Journal of Medical Microbiology - March 9, 2020 Category: Microbiology Authors: Zhang RL, Wang QQ Tags: Int J Med Microbiol Source Type: research

Recombinant N-terminal outer membrane porin (OprF) of Pseudomonas aeruginosa is a promising vaccine candidate against both P. aeruginosa and some strains of Acinetobacter baumannii.
Abstract Pseudomonas aeruginosa is an evolving pathogen which can cause serious infections especially to immunocompromised patients. Its high resistance profile to antibiotics results in difficulty, and sometimes impossibility, in treating afflicted patients. Developing an effective vaccine against P. aeruginosa is an important approach to tackle this problem. A similar problematic situation exists for Acinetobacter baumannii. Several vaccine candidates have been investigated up till now but still there is no approved vaccine in the market. One important antigen of P. aeruginosa is the outer membrane protein F (Op...
Source: International Journal of Medical Microbiology - February 29, 2020 Category: Microbiology Authors: Bahey-El-Din M, Mohamed SA, Sheweita SA, Haroun M, Zaghloul TI Tags: Int J Med Microbiol Source Type: research

Development of a novel MALDI-TOF MS-based bile solubility test for rapid discrimination of Streptococcus pneumoniae.
Abstract Differentiation of Streptococcus pneumoniae from other Streptococcus mitis group streptococci (SMGS) remains challenging despite the introduction of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). While the bile solubility test (BST) provides most reliable discrimination of pneumococci, its practical implementation is limited by subjective visual interpretation and frequent inconclusive results. We aimed to develop a rapid confirmation BST based on direct-on-target MALDI-TOF MS assay. After establishment of optimal test conditions, test performance was evaluate...
Source: International Journal of Medical Microbiology - February 14, 2020 Category: Microbiology Authors: Idelevich EA, Schlattmann A, Kostrzewa M, Becker K Tags: Int J Med Microbiol Source Type: research

Complete genome sequence and genome-scale metabolic modelling of Acinetobacter baumannii type strain ATCC 19606.
Abstract Multidrug-resistant (MDR) Acinetobacter baumannii is a critical threat to global health. The type strain ATCC 19606 has been widely used in studying the virulence, pathogenesis and mechanisms of antimicrobial resistance in A. baumannii. However, the lack of a complete genome sequence is a hindrance towards detailed bioinformatic studies. Here we report the generation of a complete genome for ATCC 19606 using PacBio sequencing. ATCC 19606 genome consists of a 3,980,848-bp chromosome and a 9,450-bp plasmid pMAC, and harbours a chromosomal dihydropteroate synthase gene sul2 conferring resistance to sulphonam...
Source: International Journal of Medical Microbiology - February 5, 2020 Category: Microbiology Authors: Zhu Y, Lu J, Zhao J, Zhang X, Yu HH, Velkov T, Li J Tags: Int J Med Microbiol Source Type: research

Analysis of the dynamics of Staphylococcus aureus binding to white blood cells using whole blood assay and geno-to-pheno mapping.
r L Abstract Given that binding and internalization of bacteria to host cells promotes infections and invasion, we aimed at characterizing how various S. aureus isolates adhere to and are internalized by different white blood cells. In particular, the role of genetic determinants on the association kinetics should be unveiled. A flow cytometric (FACS) whole blood assay with fluorescently labelled isolates was applied to 56 clinical S. aureus isolates. This phenotypic data was then linked to previously obtained genotyping data (334 genes) with the help of a redescription mining algorithm. Professional phagocytes sh...
Source: International Journal of Medical Microbiology - February 5, 2020 Category: Microbiology Authors: Gaidar D, Jonas A, Akulenko R, Ruffing U, Herrmann M, Helms V, von Müller L Tags: Int J Med Microbiol Source Type: research

Naringin sensitizes the antibiofilm effect of ciprofloxacin and tetracycline against Pseudomonas aeruginosa biofilm.
Abstract The study aims to explore the combinatorial effect of naringin with antibiotics, ciprofloxacin and tetracycline on Pseudomonas aeruginosa biofilms. The antibiofilm efficacy of selected treatment regimes against P. aeruginosa biofilm were quantified by crystal violet assay, MTT assay, Congo red binding assay, and were visualized by confocal laser scanning microscopy and scanning electron microscopy. All the assays reflected antibiofilm activities, however, combinatorial performances of naringin with antibiotics were found to be more significant. A significant reduction in swimming and swarming motilities a...
Source: International Journal of Medical Microbiology - February 5, 2020 Category: Microbiology Authors: Dey P, Parai D, Banerjee M, Hossain ST, Mukherjee SK Tags: Int J Med Microbiol Source Type: research

ClpB is an essential stress regulator of Mycobacterium tuberculosis and endows survival advantage to dormant bacilli.
Abstract The ability to tolerate multiple host derived stresses, resist eradication and persist within the infected individuals is central to the pathogenicity of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Mycobacterial survival is contingent upon sensing environmental perturbations and initiating a fitting response to counter them. Therefore, understanding of molecular mechanisms underlying stress tolerance and sensing in Mtb is critical for devising strategies for TB control. Our study aims to delineate the role of ClpB, a heat shock protein of Hsp100 family, in the general stres...
Source: International Journal of Medical Microbiology - January 23, 2020 Category: Microbiology Authors: Tripathi P, Singh LK, Kumari S, Hakiem OR, Batra JK Tags: Int J Med Microbiol Source Type: research

Cefoperazone induces esterase B expression by EstR and esterase B enhances cefoperazone activity at the periplasm.
Abstract The occurrence of antibiotic resistance bacteria has become a major threat to public health. We have recently discovered a transcriptional activator that belongs to MarR family, EstR, and an esterase B (EstB) with a newly proposed de-arenethiolase activity from Sphingobium sp. SM42. De-arenethiolase activity involves the removal of the small aromatic side chain of cephalosporin antibiotics as an excellent leaving group by the enzymatic CS bond cleavage. Here, we report the regulation of estB through EstR as an activator in response to a third generation cephalosporin, cefoperazone, antibiotic. Cefoperazon...
Source: International Journal of Medical Microbiology - January 23, 2020 Category: Microbiology Authors: Toewiwat N, Whangsuk W, Ploypradith P, Mongkolsuk S, Loprasert S Tags: Int J Med Microbiol Source Type: research

A novel type I toxin-antitoxin system modulates persister cell formation in Staphylococcus aureus.
Abstract A plethora of toxin-antitoxin systems exist in bacteria and has multilateral roles in bacterial pathogenesis and virulence. Toxin-antitoxin systems have been involved in persister cell formation in Escherichia coli and Mycobacterium but have not been reported to be associated with Staphylococcus aureus persistence. Persistence is the ability of bacterial cells to tolerate unfavorable conditions and multiple stresses. There are less known and more unknown factors that either alleviate or aggravate bacterial persistence phenomenon. For the first time, we reported a new chromosomally encoded tripartite toxin...
Source: International Journal of Medical Microbiology - January 17, 2020 Category: Microbiology Authors: Habib G, Zhu J, Sun B Tags: Int J Med Microbiol Source Type: research

The EngCP endo α-N-acetylgalactosaminidase is a virulence factor involved in Clostridium perfringens gas gangrene infections.
In conclusion, we have obtained evidence that EngCP is required for virulence in C. perfringens and, although classical exotoxins are important for disease, we have now shown that an O-glycosidase also plays an important role in the disease process. PMID: 31987726 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - January 17, 2020 Category: Microbiology Authors: Cheung JK, Adams V, D'Souza D, James M, Day CJ, Jennings MP, Lyras D, Rood JI Tags: Int J Med Microbiol Source Type: research

Resistance Sniffer: An online tool for prediction of drug resistance patterns of Mycobacterium tuberculosis isolates using next generation sequencing data.
Abstract The effective control of multidrug resistant tuberculosis (MDR-TB) relies upon the timely diagnosis and correct treatment of all tuberculosis cases. Whole genome sequencing (WGS) has great potential as a method for the rapid diagnosis of drug resistant Mycobacterium tuberculosis (Mtb) isolates. This method overcomes most of the problems that are associated with current phenotypic drug susceptibility testing. However, the application of WGS in the clinical setting has been deterred by data complexities and skill requirements for implementing the technologies as well as clinical interpretation of the next g...
Source: International Journal of Medical Microbiology - January 17, 2020 Category: Microbiology Authors: Muzondiwa D, Mutshembele A, Pierneef RE, Reva ON Tags: Int J Med Microbiol Source Type: research

Susceptibility of aging mice to listeriosis: Role of anti-inflammatory responses with enhanced Treg-cell expression of CD39/CD73 and Th-17 cells.
Abstract Foodborne Listeria monocytogenes (Lm) causes serious illness and death in immunosuppressed hosts, including the elderly population. We investigated Lm susceptibility and inflammatory cytokines in geriatric mice. Young-adult and old mice were gavaged with a Lm strain Lmo-InlAm. Tissues were assayed for Lm burden and splenocytes were analyzed for Th1/Th2/Th17/Treg responses and expression of CD39 and CD73. Old Lm-infected mice lost body-weight dose-dependently, had higher Lm colonization, and showed higher inflammatory responses than Lm-infected young-adult mice. After infection, IL-17 levels increased sign...
Source: International Journal of Medical Microbiology - January 16, 2020 Category: Microbiology Authors: Alam MS, Cavanaugh C, Pereira M, Babu U, Williams K Tags: Int J Med Microbiol Source Type: research

Prevalence of hypermutator isolates of Achromobacter spp. from cystic fibrosis patients.
sen N Abstract Bacteria colonising the lungs of cystic fibrosis (CF) patients encounter high selective pressures. Hypermutation facilitates adaptation to fluctuating environments, and hypermutator strains are frequently isolated from CF patients. We investigated the prevalence of hypermutator isolates of Achromobacter spp. among patients affiliated with the CF Centre in Aarhus, Denmark. By exposure to rifampicin, the mutation frequency was determined for 90 isolates of Achromobacter spp. cultured from 42 CF patients; 20 infections were categorised as chronic, 22 as intermittent. The genetic mechanisms of hypermuta...
Source: International Journal of Medical Microbiology - January 16, 2020 Category: Microbiology Authors: Ridderberg W, Jensen Handberg K, Nørskov-Lauritsen N Tags: Int J Med Microbiol Source Type: research

Characterization of blaCTX-M-14 transposition from plasmid to chromosome in Escherichia coli experimental strain.
In this study, we observed the frequency and molecular nature of the ISEcp1-mediated transposition of blaCTX-M-14 from a plasmid to a chromosome by using an experimental strain of Escherichia coli. We determined 102 different chromosomal transposition sites of blaCTX-M-14 in 126 E. coli isolates following five independent screening procedures. The characterization of the 102 different chromosomal transposition sites of blaCTX-M-14 observed in this study revealed the presence of 5-bp direct repeat (DR) sequences and identical left terminal inverted sequences in 80 E. coli isolates. However, 5'-flanking sequences of the righ...
Source: International Journal of Medical Microbiology - January 16, 2020 Category: Microbiology Authors: Hamamoto K, Tokunaga T, Yagi N, Hirai I Tags: Int J Med Microbiol Source Type: research

Discovery of Paenibacillus larvae ERIC V: Phenotypic and genomic comparison to genotypes ERIC I-IV reveal different inventories of virulence factors which correlate with epidemiological prevalences of American Foulbrood.
inert M Abstract Paenibacillus larvae is the etiological agent of American Foulbrood (AFB), a highly contagious brood disease of honey bees (Apis mellifera). AFB requires mandatory reporting to the veterinary authority in many countries and until now four genotypes, P. larvae ERIC I-IV, have been identified. We isolated a new genotype, ERIC V, from a Spanish honey sample. After a detailed phenotypic comparison with the reference strains of the ERIC I-IV genotypes, including spore morphology, non-ribosomal peptide (NRP) profiling, and in vivo infections of A. mellifera larvae, we established a genomic DNA Macrorest...
Source: International Journal of Medical Microbiology - January 16, 2020 Category: Microbiology Authors: Beims H, Bunk B, Erler S, Mohr KI, Spröer C, Pradella S, Günther G, Rohde M, von der Ohe W, Steinert M Tags: Int J Med Microbiol Source Type: research

Tigecycline resistance may be associated with dysregulated response to stress in Mycobacterium abscessus.
In this study, we tested this hypothesis by subjecting 7C to transcriptomic dissection using RNA sequencing. We found an over-expression of genes encoding the SigH ortholog, chaperones and oxidoreductases. In line with these findings, 7C demonstrated better survival against heat shock when compared to the wild-type ATCC 19977. Another interesting observation from the RNA-Seq analysis was the down-regulation of ribosomal protein-encoding genes. This highlights the possibility of ribosomal conformation changes which could negatively affect the binding of tigecycline to its target, leading to phenotypic resistance. We also de...
Source: International Journal of Medical Microbiology - November 18, 2019 Category: Microbiology Authors: Ng HF, Ngeow YF, Yap SF, Zin T, Tan JL Tags: Int J Med Microbiol Source Type: research

Untargeted accurate identification of highly pathogenic bacteria directly from blood culture flasks.
Abstract To improve the preparedness against exposure to highly pathogenic bacteria and to anticipate the wide variety of bacteria that can cause bloodstream infections (BSIs), a safe, unbiased and highly accurate identification method was developed. Our liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method can identify highly pathogenic bacteria, their near-neighbors and bacteria that are common causes of BSIs directly from positive blood culture flasks. The developed Peptide-Based Microbe Detection Engine (http://proteome2pathogen.com) relies on a two-step workflow: a genus-level search followed...
Source: International Journal of Medical Microbiology - November 11, 2019 Category: Microbiology Authors: Berendsen EM, Levin E, Braakman R, Prodan A, van Leeuwen HC, Paauw A Tags: Int J Med Microbiol Source Type: research

Co-existence of Citrobacter freundii exacerbated Pseudomonas aeruginosa infection in vivo.
Abstract The presence of bacterial species other than the pathogen at infection site can affect the progression of a bacterial infection. Based on the fact that Citrobacter freundii can coexist during Pseudomonas aeruginosa infection, this study aims to investigate the impact of the co-existing C. freundii on the pathogenesis of P. aeruginosa infection. A murine peritonitis model was used to compare the mortality rates and histopathology of P. aeruginosaPAO1 infection in the presence and absence of a C. freundii clinical isolate C9. We also investigated the intercellular interaction between PAO1 and C9 by examinin...
Source: International Journal of Medical Microbiology - November 11, 2019 Category: Microbiology Authors: Peng Q, Chen L, Zhou S, Li H, Long J, Yao F, Zhuang Y, Zhang Z, Huang Y, Duan K Tags: Int J Med Microbiol Source Type: research

Escherichia coli strains producing a novel Shiga toxin 2 subtype circulate in China.
Abstract Shiga toxin (Stx) is the key virulence factor in Shiga toxin producing Escherichia coli (STEC), which can cause diarrhea and hemorrhagic colitis with life-threatening complications. Stx comprises two toxin types, Stx1 and Stx2. Several Stx1/Stx2 subtypes have been identified in E. coli, which are variable in sequences, toxicity and host specificity. Here, we report the identification of a novel Stx2 subtype, designated Stx2k, in E. coli strains widely detected from diarrheal patients, animals, and raw meats in China over time. Stx2k exhibits varied cytotoxicity in vitro among individual strains. The Stx2k...
Source: International Journal of Medical Microbiology - November 9, 2019 Category: Microbiology Authors: Yang X, Bai X, Zhang J, Sun H, Fu S, Fan R, He X, Scheutz F, Matussek A, Xiong Y Tags: Int J Med Microbiol Source Type: research

Over-expression of Tgs1 in Mycobacterium marinum enhances virulence in adult zebrafish.
Abstract Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), can persist in the host for decades without causing TB symptoms and can cause a latent infection, which is an intricate challenge of current TB control. The DosR regulon, which contains approximately 50 genes, is crucial in the non-replicating persistence of Mtb. tgs1 is one of the most powerfully induced genes in this regulon during Mtb non-replicating persistence. The gene encodes a triacyl glycerol synthase catalyzing synthesis of triacyl glycerol (TAG), which is proposed as an energy source during bacilli persistence. Here, we...
Source: International Journal of Medical Microbiology - November 6, 2019 Category: Microbiology Authors: Liu DQ, Zhang JL, Pan ZF, Mai JT, Mei HJ, Dai Y, Zhang L, Wang QZ Tags: Int J Med Microbiol Source Type: research

Transcriptomic analysis of smooth versus rough Brucella melitensis Rev.1 vaccine strains reveals insights into virulence attenuation.
Abstract Brucella melitensis Rev.1 is the live attenuated Elberg-originated vaccine strain of the facultative intracellular Brucella species, and is widely used to control brucellosis in small ruminants. However, Rev.1 may cause abortions in small ruminants that have been vaccinated during the last trimester of gestation, it is pathogenic to humans, and it induces antibodies directed at the O-polysaccharide (O-PS) of the smooth lipopolysaccharide, thus making it difficult to distinguish between vaccinated and infected animals. Rough Brucella strains, which lack O-PS and are considered less pathogenic, have been in...
Source: International Journal of Medical Microbiology - October 21, 2019 Category: Microbiology Authors: Salmon-Divon M, Kornspan D Tags: Int J Med Microbiol Source Type: research

Elicitation of Th1/Th2 related responses in mice by chitosan nanoparticles loaded with Brucella abortus malate dehydrogenase, outer membrane proteins 10 and 19.
In this study, three Brucella abortus recombinant proteins, malate dehydrogenase (rMdh), outer membrane proteins (rOmp) 10 and 19 were loaded in mucoadhesive chitosan nanoparticles (CNs) and induction of mucosal and systemic immunity were investigated after intranasal immunization of BALB/c mice. These antigens were also coimmunized as cocktail (rCocktail) to evaluate multiple antigen specific vaccine candidates. At 6-weeks post-immunization (wpi), antigen specific total IgG was increased in all of the immunized groups, predominantly IgG1. In addition, spleenocyte from rMdh-, rOmp19-, and rCocktail-immunized groups signifi...
Source: International Journal of Medical Microbiology - October 18, 2019 Category: Microbiology Authors: Shim S, Soh SH, Im YB, Park HE, Cho CS, Kim S, Yoo HS Tags: Int J Med Microbiol Source Type: research

Sub-Inhibitory concentrations of SOS-Response inducing antibiotics stimulate integrase expression and excision of pathogenicity islands in uropathogenic Escherichia coli strain 536.
ndt U Abstract Urinary tract infections are one of the most common bacterial infections and a major public health problem. The predominant causative agents are uropathogenic Escherichia coli. These strains differ from commensal E. coli by the presence of additional horizontally acquired chromosomal material, so-called pathogenicity islands, which encode traits that promote efficient bacterial colonization of the urinary tract. Uropathogenic model strain E. coli 536 possesses six archetypal pathogenicity islands. Bacteriophage-like integrases encoded by each pathogenicity island contribute to island instability. To...
Source: International Journal of Medical Microbiology - October 7, 2019 Category: Microbiology Authors: Chittò M, Berger M, Klotz L, Dobrindt U Tags: Int J Med Microbiol Source Type: research

SFB 766: 12 years of research on the bacterial cell envelope.
PMID: 31575475 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - September 26, 2019 Category: Microbiology Authors: Stegmann E, Wagner S, Schwarz S Tags: Int J Med Microbiol Source Type: research

Genotypic differences in CC224, CC363, CC449 and CC446 of Moraxella catarrhalis isolates based on whole genome SNP, MLST and PFGE typing.
In conclusion, these findings provide further insight into the evolutionary characteristics of M. catarrhalis. PMID: 31570247 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - September 19, 2019 Category: Microbiology Authors: Liu YL, Yu SY, Jia XM, Zhou HJ, Sun HL, Kudinha T, Kong F, Xu HP, Xu YC Tags: Int J Med Microbiol Source Type: research

Staphylococcus petrasii diagnostics and its pathogenic potential enhanced by mobile genetic elements.
caron;iborová M, Mikulášek K, Sedláček I, Doškař J, Pantůček R Abstract Staphylococcus petrasii is recently described coagulase negative staphylococcal species and an opportunistic human pathogen, still often misidentified in clinical specimens. Four subspecies are distinguished in S. petrasii by polyphasic taxonomical analyses, however a comparative study has still not been done on the majority of isolates and their genome properties have not yet been thoroughly analysed. Here, we describe the phenotypic and genotypic characteristics of 65 isolates and the results of de novo...
Source: International Journal of Medical Microbiology - September 5, 2019 Category: Microbiology Authors: Vrbovská V, Kovařovic V, Mašlaňová I, Indráková A, Petráš P, Šedo O, Švec P, Fišarová L, Šiborová M, Mikulášek K, Sedláček I, Doškař J, Pantůček R Tags: Int J Med Microbiol Source Type: research

Mycobacterium tuberculosis DosR regulon gene Rv2004c contributes to streptomycin resistance and intracellular survival.
In this study, we attempted to characterise the Rv2004c encoded protein, a member of DosR regulon, for its role in drug resistance. In silico docking analysis revealed that Rv2004c binds with streptomycin (SM). Phosphotransferase assay demonstrated that Rv2004c possibly mediates SM resistance through the aminoglycoside phosphotransferase activity. Further, E. coli expressing Rv2004c conferred resistance to 100μM of SM in liquid broth cultures indicating a mild aminoglycoside phosphotransferase activity of Rv2004c. Moreover, we investigated the role of MSMEG_3942 (an orthologous gene of Rv2004c) encoded protein in intrac...
Source: International Journal of Medical Microbiology - August 30, 2019 Category: Microbiology Authors: Doddam SN, Peddireddy V, Yerra P, Sai Arun PP, Qaria MA, Baddam R, Sarker N, Ahmed N Tags: Int J Med Microbiol Source Type: research

Nucleases of bacterial pathogens as virulence factors, therapeutic targets and diagnostic markers.
Abstract New frontiers of therapy are being explored against the upcoming bacterial diseases rendered untreatable due to multiple, extreme and pan- antibiotic resistance. Nucleases are ubiquitous in bacterial pathogens performing various functions like acquiring nucleotide nutrients, allowing or preventing uptake of foreign DNA, controlling biofilm formation/dispersal/architecture, invading host by tissue damage, evading immune defence by degrading DNA matrix of neutrophil extracellular traps (NETs) and immunomodulating the host immune response. Secretory nucleases also provide means of survival to other bacteria ...
Source: International Journal of Medical Microbiology - August 30, 2019 Category: Microbiology Authors: Sharma P, Garg N, Sharma A, Capalash N, Singh R Tags: Int J Med Microbiol Source Type: research

Chlamydia pneumoniae infection promotes vascular smooth muscle cell migration via c-Fos/interleukin-17C signaling.
Abstract Chlamydia pneumoniae (C. pneumoniae) infection is associated with the initiation and progression of atherosclerosis. The migration of vascular smooth muscle cell (VSMC) from the media to the intima is a key event in the development of atherosclerosis. Interleukin-17C (IL-17C) could enhance cell migration ability. The aim of our study is to investigate the role of IL-17C in C. pneumoniae infection-promoted VSMC migration, thereby possibly accelerating atherosclerosis. We firstly demonstrated that C. pneumoniae infection significantly increased IL-17C expression in VSMCs in the atherosclerotic lesion area f...
Source: International Journal of Medical Microbiology - August 19, 2019 Category: Microbiology Authors: Zheng N, Zhang L, Wang B, Wang G, Liu J, Miao G, Zhao X, Liu C, Zhang L Tags: Int J Med Microbiol Source Type: research

Emerging challenges of whole-genome-sequencing-powered epidemiological surveillance of globally distributed clonal groups of bacterial infections, giving Acinetobacter baumannii ST195 as an example.
Abstract Whole-genome sequencing (WGS) has revolutionized the genotyping of bacterial pathogens and is expected to become the new gold standard for tracing the transmissions of bacterial infectious diseases for public health purposes. However, it is still unexpectedly demanding to employ WGS for global epidemiological surveillance because of the high degree of similarity between the genomes of intercontinental isolates. The aim of this study was to utilize genomically derived bioinformatics analysis to identify globally distributed A. baumannii ST195 lineage and differentiation outbreaks to address this issue. The...
Source: International Journal of Medical Microbiology - August 19, 2019 Category: Microbiology Authors: Jia H, Chen Y, Wang J, Xie X, Ruan Z Tags: Int J Med Microbiol Source Type: research

Screen for fitness and virulence factors of Francisella sp. strain W12-1067 using amoebae.
In conclusion, candidate fitness factors of the new Francisella species F-W12 were identified using the scatter screen method which might also be usable for other Francisella species. PMID: 31451389 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - August 19, 2019 Category: Microbiology Authors: Köppen K, Chen F, Rydzewski K, Einenkel R, Böttcher T, Morguet C, Grunow R, Eisenreich W, Heuner K Tags: Int J Med Microbiol Source Type: research

Molecular typing and in vitro resistance of Cryptococcus neoformans clinical isolates obtained in Germany between 2011 and 2017.
In this study, we characterised all C. neoformans isolates collected from individual patients' samples at the German reference laboratory for cryptococcosis 2011 and 2017 (n = 133) by multi-locus sequence typing and phenotypic drug susceptibility testing. We identified serotype A/genotype VNI isolates belonging to clonal complexes previously described from Europe, Africa, Asia and South America as the most prevalent agents of cryptococcosis in Germany. Overall, we observed minimal inhibitory concentrations (MICs) above the epidemiological cut-offs (ECVs) in 1.6% of isolates regarding fluconazole and 2.3% of isolates re...
Source: International Journal of Medical Microbiology - August 16, 2019 Category: Microbiology Authors: Selb R, Fuchs V, Graf B, Hamprecht A, Hogardt M, Sedlacek L, Schwarz R, Idelevich EA, Becker SL, Held J, Küpper-Tetzel CP, McCormick-Smith I, Heckmann D, Gerkrath J, Han CO, Wilmes D, Rickerts V Tags: Int J Med Microbiol Source Type: research

Rapid diagnosis of bacterial meningitis by nanopore 16S amplicon sequencing: A pilot study.
Abstract Early administration of antibiotics is crucial in the management of bacterial meningitis. Rapid pathogen identification helps to make a definite diagnosis of bacterial meningitis and enables tailored antibiotic treatment. We investigated if the 16S amplicon sequencing performed by MinION, a nanopore sequencer, was capable of rapid pathogen identification in bacterial meningitis. Six retrospective cases of confirmed bacterial meningitis and two prospective cases were included. The initial cerebrospinal fluid (CSF) samples of these patients were used for the experiments. DNA was extracted from the CSF, and ...
Source: International Journal of Medical Microbiology - August 12, 2019 Category: Microbiology Authors: Moon J, Kim N, Kim TJ, Jun JS, Lee HS, Shin HR, Lee ST, Jung KH, Park KI, Jung KY, Kim M, Lee SK, Chu K Tags: Int J Med Microbiol Source Type: research

Unraveling the mechanism of peptidoglycan amidation by the bifunctional enzyme complex GatD/MurT: A comparative structural approach.
e T Abstract The bacterial cell wall provides structural integrity to the cell and protects the cell from internal pressure and the external environment. During the course of the twelve-year funding period of the Collaborative Research Center 766, our work has focused on conducting structure-function studies of enzymes that modify (synthesize or cleave) cell wall components of a range of bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Nostoc punctiforme. Several of our structures represent promising targets for interference. In this review, we highlight a recent structure-function analysi...
Source: International Journal of Medical Microbiology - July 18, 2019 Category: Microbiology Authors: Nöldeke ER, Stehle T Tags: Int J Med Microbiol Source Type: research

Environmental and cellular factors affecting the localization of T6SS proteins in Burkholderia thailandensis.
z S Abstract The type VI secretion system (T6SS) injects effector proteins into neighboring bacteria and host cells. Effector translocation is driven by contraction of a tubular sheath in the cytoplasm that expels an inner needle across the cell envelope. The AAA + ATPase ClpV disassembles and recycles the contracted sheath. While ClpV-1-GFP of the Burkholderia T6SS-1, which targets prokaryotic cells, assembles into randomly localized foci, ClpV-5-GFP of the virulence-associated T6SS-5 displays a polar distribution. The mechanisms underlying the localization of T6SSs to a particular site in the bacterial cell ...
Source: International Journal of Medical Microbiology - July 18, 2019 Category: Microbiology Authors: Lennings J, Makhlouf M, Olejnik P, Mayer C, Brötz-Oesterhelt H, Schwarz S Tags: Int J Med Microbiol Source Type: research

Function and regulation of Staphylococcus aureus wall teichoic acids and capsular polysaccharides.
z C Abstract Staphylococcus aureus produces different secondary cell wall glycopolymers such as wall teichoic acids (WTA) and capsular polysaccharides (CP). These structures play an important role in S. aureus colonization, pathogenesis and bacterial evasion of the host immune defences. To fulfil their diverse functions, biosynthesis of both glycopolymers has to be tightly controlled. Regulation of WTA biosynthesis and modification is only partially understood. The transcription factor MgrA and the two-component systems (TCS) Agr, GraRS, and ArlRS control WTA export, chain-length and modification. CP synthesis is ...
Source: International Journal of Medical Microbiology - July 18, 2019 Category: Microbiology Authors: Keinhörster D, George SE, Weidenmaier C, Wolz C Tags: Int J Med Microbiol Source Type: research

Diversity of peptidoglycan structure-Modifications and their physiological role in resistance in antibiotic producers.
Abstract Peptidoglycan (PG) is a bacteria specific cell surface layer that ensures the bacterial shape and integrity. The two actinomycetes Amycolatopsis balhimycina and Microbispora sp. PTA-5024 are producers of PG targeting antibiotics. To prevent the binding of their secreted product to their own PG, they developed specific self-resistance mechanisms. Modifications of PG, which are applied by both strains, are the introduction of amide-residues at the PG precursors and the alternative crosslinks within the nascent PG. The PG modifications found in Microbispora sp. PTA-5024 seemed to be an intrinsic characterist...
Source: International Journal of Medical Microbiology - July 17, 2019 Category: Microbiology Authors: Unsleber S, Wohlleben W, Stegmann E Tags: Int J Med Microbiol Source Type: research

Consequences of dosing and timing on the antibacterial effects of ADEP antibiotics.
t H Abstract Antibiotic acyldepsipeptides (ADEPs) exert potent antibacterial activity in rodent models of bacterial infection and exceptional efficacy against persister cells of methicillin-resistant Staphylococcus aureus (MRSA). The mechanism of ADEP action is unusual in that the antibiotic releases the destructive capacity of over-activated ClpP, the proteolytic core of the bacterial Clp protease. The essential bacterial cell division protein FtsZ had emerged in a previous study as a preferred protein substrate of ADEP-activated ClpP but it is definitely not the only cellular substrate. In the current study, we ...
Source: International Journal of Medical Microbiology - July 14, 2019 Category: Microbiology Authors: Mayer C, Sass P, Brötz-Oesterhelt H Tags: Int J Med Microbiol Source Type: research

Role of α-glucan-induced oxygen species in dendritic cells and its impact in immune response against tuberculosis.
Role of α-glucan-induced oxygen species in dendritic cells and its impact in immune response against tuberculosis. Int J Med Microbiol. 2019 Jul 11;:151328 Authors: Romero MM, Duarte A, Pastorini M, Alemán M Abstract With 10 million new cases and three million deaths estimated to occur yearly ̶ more than any time in history ̶ tuberculosis (TB) remains the single most widespread and deadly infectious disease. Until recently, it was thought that both latent and active TB was primarily related to host factors. Nonetheless, the participation of bacterial factors is becoming increasingly evi...
Source: International Journal of Medical Microbiology - July 11, 2019 Category: Microbiology Authors: Romero MM, Duarte A, Pastorini M, Alemán M Tags: Int J Med Microbiol Source Type: research