International Journal of Medical Microbiology This is an RSS file. You can use it to subscribe to this data in your favourite RSS reader or to display this data on your own website or blog.
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
Role of the Streptomyces spore wall synthesizing complex SSSC in differentiation of Streptomyces coelicolor A3(2).
Abstract A crucial stage of the Streptomyces life cycle is the sporulation septation, a process were dozens of cross walls are synchronously formed in the aerial hyphae in a highly coordinated manner. This process includes the remodeling of the spore envelopes to make Streptomyces spores resistant to detrimental environmental conditions. Sporulation septation and the synthesis of the thickened spore envelope in S. coelicolor A3(2) involves the Streptomyces spore wall synthesizing complex SSSC. The SSSC is a multi-protein complex including proteins directing peptidoglycan synthesis (MreBCD, PBP2, Sfr, RodZ) and cel...
Source: International Journal of Medical Microbiology - July 11, 2019 Category: Microbiology Authors: Vollmer B, Steblau N, Ladwig N, Mayer C, Macek B, Mitousis L, Sigle S, Walter A, Wohlleben W, Muth G Tags: Int J Med Microbiol Source Type: research
Bacteria's different ways to recycle their own cell wall.
a M Abstract The ability to recover components of their own cell wall is a common feature of bacteria. This was initially recognized in the Gram-negative bacterium Escherichia coli, which recycles about half of the peptidoglycan of its cell wall during one cell doubling. Moreover, E. coli was shown to grow on peptidoglycan components provided as nutrients. A distinguished recycling enzyme of E. coli required for both, recovery of the cell wall sugar N-acetylmuramic acid (MurNAc) of the own cell wall and for growth on external MurNAc, is the MurNAc 6-phosphate (MurNAc 6P) lactyl ether hydrolase MurQ. We revealed ho...
Source: International Journal of Medical Microbiology - July 4, 2019 Category: Microbiology Authors: Mayer C, Kluj RM, Mühleck M, Walter A, Unsleber S, Hottmann I, Borisova M Tags: Int J Med Microbiol Source Type: research
Assessing capreomycin resistance on tlyA deficient and point mutation (G695A) Mycobacterium tuberculosis strains using multi-omics analysis.
Abstract Capreomycin (CAP), a cyclic peptide antibiotic, is considered to be an ideal second-line drug for tuberculosis (TB). However, in the past few years, the emergence of more CAP-resistant (CAPr) TB patients has limited its use. Although it has been reported that CAP resistance to Mycobacterium tuberculosis (Mtb) is associated with rrs or tlyA mutation, the exact mechanism of CAPr Mtb strains, especially the mechanism associated with tlyA deficient or mutation, is not fully understood. Herein, we utilized a multi-omics (genome, proteome, and metabolome) approach to assess CAP resistance on tlyA deficient CAPr...
Source: International Journal of Medical Microbiology - June 24, 2019 Category: Microbiology Authors: Zhao J, Wei W, Yan H, Zhou Y, Li Z, Chen Y, Zhang C, Zeng J, Chen T, Zhou L Tags: Int J Med Microbiol Source Type: research
The multicopper oxidase of Mycobacterium tuberculosis (MmcO) exhibits ferroxidase activity and scavenges reactive oxygen species in activated THP-1 cells.
Abstract The MmcO protein of Mycobacterium tuberculosis is a membrane-associated multicopper oxidase. Its natural substrate(s) and its role in pathogenesis are not well characterized. A recent report proposes that MmcO contributes to copper resistance in M. tuberculosis during infection. We have expressed and reconstituted the active enzyme from inclusion bodies in E. coli. MmcO exhibits maximal activity against the experimental substrate 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) or ABTS, at pH 4. The enzyme also exhibits ferroxidase activity at pH 4. Most notable was the finding that MmcO is able t...
Source: International Journal of Medical Microbiology - June 24, 2019 Category: Microbiology Authors: Kinkar E, Kinkar A, Saleh M Tags: Int J Med Microbiol Source Type: research
Identification of two abundant Aerococcus urinae cell wall-anchored proteins.
ussen M Abstract Aerococcus urinae is an emerging pathogen that causes urinary tract infections, bacteremia and infective endocarditis. The mechanisms through which A. urinae cause infection are largely unknown. The aims of this study were to describe the surface proteome of A. urinae and to analyse A. urinae genomes in search for genes encoding surface proteins. Two proteins, denoted Aerococcal surface protein (Asp) 1 and 2, were through the use of mass spectrometry based proteomics found to quantitatively dominate the aerococcal surface. The presence of these proteins on the surface was also shown using ELISA wi...
Source: International Journal of Medical Microbiology - June 24, 2019 Category: Microbiology Authors: Senneby E, Sunnerhagen T, Hallström B, Lood R, Malmström J, Karlsson C, Rasmussen M Tags: Int J Med Microbiol Source Type: research
Assembly and targeting of secretins in the bacterial outer membrane.
Abstract In Gram-negative bacteria, secretion of toxins ensure the survival of the bacterium. Such toxins are secreted by sophisticated multiprotein systems. The most conserved part in some of these secretion systems are components, called secretins, which form the outer membrane ring in these systems. Recent structural studies shed some light on the oligomeric organization of secretins. However, the mechanisms by which these proteins are targeted to the outer membrane and assemble there into ring structures are still not fully understood. This review discusses the various species-specific targeting and assembly p...
Source: International Journal of Medical Microbiology - June 19, 2019 Category: Microbiology Authors: Natarajan J, Singh N, Rapaport D Tags: Int J Med Microbiol Source Type: research
Cryopreservation of the human gut microbiota: Current state and perspectives.
Abstract The human intestinal microbiota is a complex ecosystem that consists of thousands of bacterial species that are responsible for human health and disease. The intestinal microbiota is a natural resource for production of therapeutic and preventive medicals, such as probiotics and fecal transplants. Modern lifestyles have resulted in the extinction of evolutionally selected microbial populations upon exposure to environmental factors. Therefore, it is very important to preserve the human gut microbiota to have the opportunity for timely restoration with minimal safety risks. Cryopreservation techniques that...
Source: International Journal of Medical Microbiology - June 4, 2019 Category: Microbiology Authors: Smirnova DV, Zalomova LV, Zagainova AV, Makarov VV, Mezhevikina LM, Fesenko EE, Yudin SM Tags: Int J Med Microbiol Source Type: research
Bacterial adhesion and host cell factors leading to effector protein injection by type III secretion system.
Abstract Type III secretion systems (T3SS) play a crucial role for virulence in many Gram-negative bacteria. After tight bacterial contact to host cells, the T3SS injects effector proteins into the host cells, which leads to cell invasion, tissue destruction and/or immune evasion. Over the last decade several attempts were made to characterize the host-cell interactions which precede and determine effector protein injection during infection. The development of the TEM-β-lactamase reporter was an important breakthrough to achieve this goal. By this means it was demonstrated that during infection with many Gram...
Source: International Journal of Medical Microbiology - June 4, 2019 Category: Microbiology Authors: Bohn E, Sonnabend M, Klein K, Autenrieth IB Tags: Int J Med Microbiol Source Type: research
MprF-mediated daptomycin resistance.
Abstract Daptomycin has become an important antibiotic for the treatment of serious Methicillin-Resistant Staphylococcus aureus (MRSA) infections. Unlike other approved antibiotics, its mode of action is still under active investigation, as well as the molecular basis of daptomycin resistance, which emerges in some cases during daptomycin treatment. Small nucleotide polymorphisms (SNPs) in the Multiple Peptide Resistance Factor (MprF) appear to play a major role in the resistance mechanism. Until recently, the impact of the SNPs on MprF activity has remained unclear, which is due to conflicting reports on resistan...
Source: International Journal of Medical Microbiology - June 4, 2019 Category: Microbiology Authors: Ernst CM, Peschel A Tags: Int J Med Microbiol Source Type: research
Structural diversity of coiled coils in protein fibers of the bacterial cell envelope.
Abstract The cell envelope of bacteria shows great diversity in architecture and composition, to a large extent due to its proteome. Proteins localized to the cell envelope, whether integrally embedded in the membrane, membrane-anchored, or peripherally associated as part of a macromolecular complex, often form elongated fibers, in which coiled coils represent a prominent structural element. These coiled-coil segments show a surprising degree of structural variability, despite being shaped by a small number of simple biophysical rules, foremost being their geometry of interaction referred to as 'knobs-into-holes'....
Source: International Journal of Medical Microbiology - June 3, 2019 Category: Microbiology Authors: Hernandez Alvarez B, Bassler J, Lupas AN Tags: Int J Med Microbiol Source Type: research
Type I interferon induced by TLR2-TLR4-MyD88-TRIF-IRF3 controls Mycobacterium abscessus subsp. abscessus persistence in murine macrophages via nitric oxide.
In this study, we analyzed the IFNβ expression of murine macrophages infected with a MAB rough colony strain (MAB-R) isolated from a patient with progressive CF and compared it to macrophages infected with the MAB smooth colony type reference strain (MAB-S). We found that MAB-R infected macrophages expressed significantly more IFNβ mRNA and protein than MAB-S infected macrophages. Higher IFNβ induction by MAB-R was associated with higher TNF expression and intracellular killing while low IFNβ induction was associated with lower TNF expression and persistence of MAB-S. IFNβ induction was independent...
Source: International Journal of Medical Microbiology - June 1, 2019 Category: Microbiology Authors: Ruangkiattikul N, Rys D, Abdissa K, Rohde M, Semmler T, Tegtmeyer PK, Kalinke U, Schwarz C, Lewin A, Goethe R Tags: Int J Med Microbiol Source Type: research
Biogenesis and function of the autotransporter adhesins YadA, intimin and invasin.
z M Abstract Bacteria often express numerous virulence factors. These virulence factors make them successful pathogens, by e.g. mediating attachment to host cells and thereby facilitating persistence or invasion, or by contributing to the evasion of the host immune system to allow proliferation and spread within the host and in the environment. The site of first contact of Gram negative bacteria with the host is the bacterial outer membrane (OM). Consisting of an asymmetrical lipid bilayer with phospholipids forming the inner, and lipopolysaccharides forming the outer leaflet, the OM harbors numerous integral memb...
Source: International Journal of Medical Microbiology - June 1, 2019 Category: Microbiology Authors: Leibiger K, Schweers JM, Schütz M Tags: Int J Med Microbiol Source Type: research
Live-cell imaging of Streptomyces conjugation.
Abstract Time-lapse imaging of conjugative plasmid transfer in Streptomyces revealed intriguing insights into the unique two-step conjugation process of this Gram+ mycelial soil bacterium. Differentially labelling of donor and recipient strains with distinct fluorescent proteins allowed the visualization of plasmid transfer in living mycelium. In nearly all observed matings, plasmid transfer occurred when donor and recipient hyphae made intimate contact at the lateral walls. Plasmid transfer does not involve a complete fusion of donor and recipient hyphae, but depends on a pore formed by the FtsK-like DNA transloc...
Source: International Journal of Medical Microbiology - May 31, 2019 Category: Microbiology Authors: Thoma L, Vollmer B, Oesterhelt F, Muth G Tags: Int J Med Microbiol Source Type: research
Caprazamycins: Biosynthesis and structure activity relationship studies.
Abstract Cell wall biosynthesis represents a valid target for antibacterial action but only a limited number of chemical structure classes selectively interact with specific enzymes or protein structures like transporters of the cell envelope. The integral membrane protein MraY translocase is essential for peptidoglycan biosynthesis catalysing the transfer of the peptidoglycan precursor phospho-MurNAc-pentapeptide to the lipid carrier undecaprenyl phosphate, thereby generating the cell wall intermediate lipid I. Not present in eukaryotic cells, MraY is a member of the superfamily of yet not well-understood integra...
Source: International Journal of Medical Microbiology - May 24, 2019 Category: Microbiology Authors: Wiker F, Hauck N, Grond S, Gust B Tags: Int J Med Microbiol Source Type: research
The prevalence of Staphylococcus aureus with mucoid phenotype in the airways of patients with cystic fibrosis-A prospective study.
CONCLUSIONS: In our prospective study, mucoid S. aureus was present in 8.6% of S. aureus-positive CF-patients. In 6 of 7 patients, mucoid isolates carried the 5bp-deletion, indicating that also other so far not identified mechanisms cause excessive biofilm formation. Further studies are necessary to ascertain the clinical impact of mucoid S. aureus phenotypes on the severity of the CF disease. PMID: 31122879 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - May 11, 2019 Category: Microbiology Authors: Lennartz FE, Schwartbeck B, Dübbers A, Große-Onnebrink J, Kessler C, Küster P, Schültingkemper H, Peters G, Kahl BC Tags: Int J Med Microbiol Source Type: research
Effect of amyloid curli fibrils and curli CsgA monomers from Escherichia coli on in vitro model of intestinal epithelial barrier stimulated with cytokines.
ian A Abstract Amyloid curli fibrils produced by Escherichia coli are well-known virulence factor influencing E. coli adhesion and biofilm formation. However, the impact of curli on intestinal epithelial barrier stimulated with proinflammatory cytokines is unknown. In the study, we examined the effect of curli produced by nonpathogenic E. coli K-12 and wild-type E. coli EC32 strains, and purified CsgA proteins on differentiated Caco-2 cell monolayers stimulated with a mixture of IL-1β, TNF-α, and INFγ cytokines as a model of 'inflamed intestinal epithelial barrier' in vitro. The results of the stu...
Source: International Journal of Medical Microbiology - May 11, 2019 Category: Microbiology Authors: Sobieszczańska B, Pawłowska B, Duda-Madej A, Pawlik K, Wiśniewski J, Grzegrzółka J, Turniak M, Walczuk U, Gamian A Tags: Int J Med Microbiol Source Type: research
Genomic investigation of a sequence type 67 Clostridium difficile causing community-acquired fulminant colitis in Hong Kong.
Abstract In 2017, we identified a Clostridium difficile strain HKCD4 that caused community-acquired fulminant colitis in a previously healthy child. Phylogenetically, it belonged to clade 2, sequence type 67 and was resistant to fluoroquinolone and tetracycline. The strain was pathogenicity locus and binary toxin positive. It has a mutation in the trehalose repressor treR leading to the L172I substitution that was previously reported in the epidemic ribotype 027 lineage. HKCD4 has a tcdB sequence that shared very high identities with 3 highly virulent reference strains. It has a CpG depleted genome that is charact...
Source: International Journal of Medical Microbiology - May 11, 2019 Category: Microbiology Authors: Cao H, Wong SC, Yam WC, Liu MC, Chow KH, Wu AK, Ho PL Tags: Int J Med Microbiol Source Type: research
Enhanced microbiological surveillance reveals that temporal case clusters contribute to the high rates of campylobacteriosis in a model agroecosystem.
Abstract Infections by pathogenic Campylobacter species were determined in diarrheic (n = 2,217) and non-diarrheic control (n = 104) people in Southwestern Alberta (SWA), Canada over a 1-year period using specialized and conventional isolation, and direct PCR. Overall, 9.9% of diarrheic individuals were positive for C. jejuni (9.1%), C. upsaliensis (0.6%), and C. coli (0.5%). No C. lari was detected. Four diarrheic individuals were co-infected with C. jejuni and C. coli, and four different individuals were co-infected with C. jejuni and C. upsaliensis. Two control individuals were posit...
Source: International Journal of Medical Microbiology - April 28, 2019 Category: Microbiology Authors: Inglis GD, Boras VF, Webb AL, Suttorp VV, Hodgkinson P, Taboada EN Tags: Int J Med Microbiol Source Type: research
A small non-coding RNA facilitates Brucella melitensis intracellular survival by regulating the expression of virulence factor.
In this study, we characterized the role of a novel sRNA, BSR1141, in the intracellular survival and virulence of Brucella melitensis. The results show that BSR1141 was highly induced during host infections and under in vitro stress situations that simulated the conditions encountered within host phagocytes. In addition, a BSR1141 mutant showed reduced survival both under in vitro stress conditions and in mice, confirming the role of BSR1141 in Brucella intracellular survival. Bioinformatic and experimental approaches revealed that BSR1141 affects the expression of many target genes, including the Brucella virulence compon...
Source: International Journal of Medical Microbiology - April 19, 2019 Category: Microbiology Authors: Wang Y, Ke Y, Duan C, Ma X, Hao Q, Song L, Guo X, Sun T, Zhang W, Zhang J, Zhao Y, Zhong Z, Yang X, Chen Z Tags: Int J Med Microbiol Source Type: research
Porin loss in Klebsiella pneumoniae clinical isolates impacts production of virulence factors and survival within macrophages.
Abstract Clinical isolates of Klebsiella pneumoniae are often resistant to beta-lactam antibiotics via the acquisition of extended spectrum beta lactamase (ESBL) enzymes paired with loss of one or both major outer membrane porins. It has been well established that loss of OmpK35 and/or OmpK36 correlates with increased minimum inhibitory concentrations of antibiotics that target the peptidoglycan. However, little is known concerning the downstream effects porin loss might have on other major virulence factors such as the polysaccharide capsule or LPS. Furthermore, it is unknown whether these cumulative changes impa...
Source: International Journal of Medical Microbiology - April 16, 2019 Category: Microbiology Authors: Brunson DN, Maldosevic E, Velez A, Figgins E, Ellis TN Tags: Int J Med Microbiol Source Type: research
Comprehensive proteomic analysis and pathogenic role of membrane vesicles of Listeria monocytogenes serotype 4b reveals proteins associated with virulence and their possible interaction with host.
In this study, the membrane vesicles (MVs) of L. monocytogenes were isolated from the culture supernatant. High-resolution electron microscopy and dynamic light scattering analysis revealed that L. monocytogenes MVs are spherical with a diameter of 200 to 300 nm in size. Further, comprehensive proteomic analyses of MVs and whole cells of L. monocytogenes were performed using LC/MS/MS. A total of 1355 and 312 proteins were identified in the L. monocytogenes cells and MVs, respectively. We identified that 296 proteins are found in both whole cells, and MV proteome and 16 proteins were identified only in the MVs. Also,...
Source: International Journal of Medical Microbiology - March 28, 2019 Category: Microbiology Authors: Karthikeyan R, Gayathri P, Gunasekaran P, Jagannadham MV, Rajendhran J Tags: Int J Med Microbiol Source Type: research
In search of a function for the membrane anchors of class IIIa adenylate cyclases.
Abstract Nine pseudoheterodimeric mammalian adenylate cyclases possess two dissimilar hexahelical membrane domains (TM1 and TM2), two dissimilar cyclase-transducing-elements (CTEs) and two complementary catalytic domains forming a catalytic dimer (often termed cyclase-homology-domain, CHD). Canonically, these cyclases are regulated by G-proteins which are released upon ligand activation of G-protein-coupled receptors. So far, a biochemical function of the membrane domains beyond anchoring has not been established. For almost 30 years, work in our laboratory was based on the hypothesis that these voluminous membran...
Source: International Journal of Medical Microbiology - March 22, 2019 Category: Microbiology Authors: Finkbeiner M, Grischin J, Seth A, Schultz JE Tags: Int J Med Microbiol Source Type: research
Secreted proteases: A new insight in the pathogenesis of extraintestinal pathogenic Escherichia coli.
Abstract Bacterial secreted proteases are the key factors that increase the virulence potential of different pathogens. Extraintestinal pathogenic E. coli (ExPEC) is a distinct pathotype that has unique ability to infect various body sites apart from the gastrointestinal tract causing several life-threatening diseases both in human and animals. Thus, understanding of ExPEC pathogenesis is crucial in effective management of disease caused by these pathogens. It is known that ExPEC possesses a broad spectrum of virulence factors including the secreted proteases which elude the host defence system. Recent studies hav...
Source: International Journal of Medical Microbiology - March 22, 2019 Category: Microbiology Authors: Tapader R, Basu S, Pal A Tags: Int J Med Microbiol Source Type: research
Carriage meningococcal isolates with capsule null locus dominate among high school students in a non-endemic period, Italy, 2012-2013.
Abstract Meningococcal disease incidence in Italy remains quite low in the overall population except for infants. Within a study on carriage isolates among high school students we aimed to define: i) the prevalence of carriage isolates, ii) the phenotypic and iii) the molecular features of meningococci by Whole Genome Sequencing (WGS). A total of 1697 pharyngeal samples from undergraduate students (age range 14-19 years) were collected from 2012 to 2013 from six larger cities in Italy. One hundred and twenty culture positive meningococci (7%) were analyzed. Carriage isolates were sent to the National Reference Lab...
Source: International Journal of Medical Microbiology - March 6, 2019 Category: Microbiology Authors: Neri A, Fazio C, Ambrosio L, Vacca P, Barbui A, Daprai L, Vocale C, Santino I, Conte M, Rossi L, Ciammaruconi A, Anselmo A, Lista F, Stefanelli P Tags: Int J Med Microbiol Source Type: research
Biofilm development and computational screening for new putative inhibitors of a homolog of the regulatory protein BrpA in Streptococcus dysgalactiae subsp. dysgalactiae.
hes I Abstract Streptococcus dysgalactiae subsp. dysgalactiae (SDSD), a Lancefield group C streptococci (GCS), is a frequent cause of bovine mastitis. This highly prevalent disease is the costliest in dairy industry. Adherence and biofilm production are important factors in streptoccocal pathogenesis. We have previously described the adhesion and internalization of SDSD isolates in human cells and now we describe the biofilm production capability of this bacterium. In this work we integrated microbiology, imaging and computational methods to evaluate the biofilm production capability of SDSD isolates; to assess th...
Source: International Journal of Medical Microbiology - February 19, 2019 Category: Microbiology Authors: Alves-Barroco C, Roma-Rodrigues C, Balasubramanian N, Guimarães MA, Ferreira-Carvalho BT, Muthukumaran J, Nunes D, Fortunato E, Martins R, Santos-Silva T, Figueiredo AMS, Fernandes AR, Santos-Sanches I Tags: Int J Med Microbiol Source Type: research
Virulence-related genes are associated with clinical and nutritional outcomes of Shigella/Enteroinvasive Escherichia coli pathotype infection in children from Brazilian semiarid region: A community case-control study.
This study aimed to correlate Shigella/EIEC virulence-related genes (VRGs) with clinical symptoms, nutritional status and coenteropathogens in children from the Brazilian semiarid region. We designed a case-control study of community diarrhea in six cities of the Brazil semiarid region with 1200 children aging 2-36 months. Standardized questionnaire was applied for collecting sociodemographic, nutritional status and clinical information of the children. DNA samples were extracted from stools and diagnosed for Shigella/EIEC using PCR-based approaches. Positive samples were tested for 28 VRGs using four multiplex PCRs. Intes...
Source: International Journal of Medical Microbiology - January 31, 2019 Category: Microbiology Authors: Bona M, Medeiros PH, Santos AK, Freitas T, Prata M, Veras H, Amaral M, Oliveira D, Havt A, Lima AÂ Tags: Int J Med Microbiol Source Type: research
Mig-14 may contribute to Salmonella enterica serovar Typhi resistance to polymyxin B by decreasing the permeability of the outer-membrane and promoting the formation of biofilm.
In this study, we demonstrated that mig-14 also played a crucial role in Salmonella enterica serovar Typhi (S. Typhi) resistance to PB. A series of genes associated with drug-resistance controlled by Mig-14 were identified in the presence of PB. Among which, ompF and ompC were up-regulated 8 and 6 folds in mig-14 mutant (Δmig-14) strains, respectively. Further, the deletion of ompF or/and ompC in Δmig-14 strains decreased their sensitivity to PB. Besides, the biofilm formation ability was reduced in Δmig-14 strains. Our results indicate that Mig-14 may contribute to PB resistance in S. Typhi by decreasing...
Source: International Journal of Medical Microbiology - January 16, 2019 Category: Microbiology Authors: Sheng X, Wang W, Chen L, Zhang H, Zhang Y, Xu S, Xu H, Huang X Tags: Int J Med Microbiol Source Type: research
Alterations on growth and cell organization of Giardia intestinalis trophozoites after treatment with KH-TFMDI, a novel class III histone deacetylase inhibitor.
Abstract Giardia trophozoites have developed resistance mechanisms to currently available compounds, leading to treatment failures. In this context, the development of new additional agents is mandatory. Sirtuins, which are class III NAD+-dependent histone deacetylases, have been considered important targets for the development of new anti-parasitic drugs. Here, we evaluated the activity of KH-TFMDI, a novel 3-arylideneindolin-2-one-type sirtuin inhibitor, on G. intestinalis trophozoites. This compound decreased the trophozoite growth presenting an IC50 value lower than nicotinamide, a moderately active inhibitor ...
Source: International Journal of Medical Microbiology - January 15, 2019 Category: Microbiology Authors: Gadelha APR, Bravim B, Vidal J, Reignault LC, Cosme B, Huber K, Bracher F, de Souza W Tags: Int J Med Microbiol Source Type: research
Characterization of a novel protein of Leptospira interrogans exhibiting plasminogen, vitronectin and complement binding properties.
Abstract Leptospirosis is a severe zoonosis caused by pathogenic species of the genus Leptospira. This work focuses on a hypothetical protein of unknown function, encoded by the gene LIC13259, and predicted to be a surface protein, widely distributed among pathogenic leptospiral strain. The gene was amplified from L. interrogans serovar Copenhageni, strain Fiocruz L1-130, cloned and the protein expressed using Escherichia coli as a host system. Immunofluorescence assay showed that the protein is surface-exposed. The recombinant protein LIC13259 (rLIC13259) has the ability to interact with the extracellular matrix ...
Source: International Journal of Medical Microbiology - January 6, 2019 Category: Microbiology Authors: Cavenague MF, Teixeira AF, Filho AS, Souza GO, Vasconcellos SA, Heinemann MB, Nascimento ALTO Tags: Int J Med Microbiol Source Type: research
Phenotypic and molecular characterization of Escherichia albertii: Further surrogates to avoid potential laboratory misidentification.
Abstract Escherichia albertii is an emerging gastrointestinal pathogen, related to Escherichia coli, which can be misidentified as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC), due to the presence of the eae gene in E. albertii. The aim of this study was to verify our hypothesis that E. coli cytolethal distending toxin-II (Eccdt-II) gene-positive E. coli is E. albertii and to accumulate the data regarding the bacteriological characteristics of E. albertii. For these purposes, we attempted to detect E. albertii in eae gene-positive bacteria previously identified as E. coli and to examine if ...
Source: International Journal of Medical Microbiology - December 30, 2018 Category: Microbiology Authors: Hinenoya A, Ichimura H, Awasthi SP, Yasuda N, Yatsuyanagi J, Yamasaki S Tags: Int J Med Microbiol Source Type: research
Acinetobacter baumannii outer membrane protein A induces HeLa cell autophagy via MAPK/JNK signaling pathway.
Abstract Autophagy is an evolutionary conserved self-balancing process that plays an important role in maintaining cellular homeostasis via the clearance of damaged organelles and misfolded proteins. Infection-triggered autophagy specifically inhibits the invasion of intracellular bacterial replication and hence protects the cells from microbial infections. It has been reported that Acinetobacter baumannii trigger cell autophagy. However, the role of its virulence protein OmpA remains unclear. Therefore, this study aimed to explore the effects of Acinetobacter baumannii OmpA on cell autophagy and its underlying mo...
Source: International Journal of Medical Microbiology - December 30, 2018 Category: Microbiology Authors: An Z, Huang X, Zheng C, Ding W Tags: Int J Med Microbiol Source Type: research
The ArlR-MgrA regulatory cascade regulates PIA-dependent and protein-mediated biofilm formation in Rbf-dependent and Rbf-independent pathways.
Abstract The two-component system response regulator ArlR and the global regulator MgrA in Staphylococcus aureus participated in numerous biological processes including biofilm formation inhibition. Previous studies have shown that these two regulators could function as a regulatory cascade. Rbf is a positive regulator of biofilm formation enhancing the production of PIA (polysaccharide intercellular adhesin). Here we have demonstrated that both ArlR and MgrA can directly bind to the promoter of rbf and repress its expression. ArlR and MgrA can also directly bind to the promoter of ica operon and enhance the expre...
Source: International Journal of Medical Microbiology - December 29, 2018 Category: Microbiology Authors: Jin Z, Jiang Q, Fang B, Sun B Tags: Int J Med Microbiol Source Type: research
Distribution of the pilS gene in Escherichia coli pathovars, its transfer ability and influence in the typical enteropathogenic E. coli adherence phenotype.
In this study, we investigated the occurrence of the two pilS alleles (pilSEc404 and pilSC1096) in tEPEC strains of different serotypes, origins and years of isolation. We also examined the potential relationship of pilS with the AA-like phenotype, its ability to be transferred by conjugation, and occurrence among strains of the other E. coli pathovars. The pilS alleles were found in 90 (55.2%) of 163 tEPEC strains, with pilSEc404 occurring more often (30.7%) than pilSC1096 (25.1%). About 21 tEPEC serotypes carried pilS. The pilS alleles were found in tEPEC strains from Chile, Peru and different Brazilian cities, with the ...
Source: International Journal of Medical Microbiology - December 11, 2018 Category: Microbiology Authors: Garcia BG, Castro FS, Vieira MAM, Girão DM, Uenishi LT, Cergole-Novella MC, Dos Santos LF, Piazza RMF, Hernandes RT, Gomes TAT Tags: Int J Med Microbiol Source Type: research
Effects of CwlM on autolysis and biofilm formation in Mycobacterium tuberculosis and Mycobacterium smegmatis.
In conclusion, the cwlM gene plays a key regulatory role in biofilm formation in M. tuberculosis and M. smegmatis. This study provided a theoretical basis for using peptidoglycan hydrolase as a target for the inhibition of biofilms. PMID: 30563740 [PubMed - as supplied by publisher] (Source: International Journal of Medical Microbiology)
Source: International Journal of Medical Microbiology - December 11, 2018 Category: Microbiology Authors: Wang C, Zhang Q, Tang X, An Y, Li S, Xu H, Li Y, Wang X, Luan W, Wang Y, Liu M, Yu L Tags: Int J Med Microbiol Source Type: research