@article{NawazKhanNoacketal.2020, author = {Nawaz, Shiza and Khan, Muhammad Moman and Noack, Jonas and Awan, Asad Bashir and Schiebel, Juliane and Roggenbuck, Dirk and Schierack, Peter and Sarwar, Yasra and Ali, Aamir}, title = {Rapid detection of biofilm formation by zoonotic serovars of Salmonella enterica and avian pathogenic E. coli isolates from poultry}, series = {Pakistan veterinary journal}, volume = {40}, journal = {Pakistan veterinary journal}, number = {4}, publisher = {University of Agriculture, Faculty of Veterinary Science}, address = {Faisalabad}, issn = {0253-8318}, doi = {10.29261/pakvetj/2020.066}, pages = {527 -- 530}, year = {2020}, abstract = {Biofilms are complex, sessile microbial communities that are problematic in clinical settings due to their association with survival and pathogenicity of bacteria. The biofilm formation supporting conditions for zoonotic serovars of Salmonella and avian pathogenic E. coli (APEC) from poultry have not been well studied yet. Clinical isolates of zoonotic Salmonella and APEC from poultry were evaluated for biofilm formation in four media at 37 degrees C and 40 degrees C after incubation of 48 and 72 hrs. The biofilms formed in 96 well plates were visualized and quantified with a new module of Aklides system using fluorescence microscope coupled with automated VideoScan Technology. After 72 hrs, brain heart infusion at 40 degrees C and Rappaport-Vassiliadis Soya broth at 37 degrees C were found most suitable for APEC and Salmonella biofilm formations respectively. The new information will be useful for further biofilm associated studies particularly for evaluation of antibiofilm compounds and contribute in infection control. (C) 2020 PVJ. All rights reserved}, language = {en} } @article{StephanBroekerSaragliadisetal.2020, author = {Stephan, Mareike Sophia and Br{\"o}ker, Nina K. and Saragliadis, Athanasios and Roos, Norbert and Linke, Dirk and Barbirz, Stefanie}, title = {In vitro analysis of O-antigen-specific bacteriophage P22 inactivation by Salmonella outer membrane vesicles}, series = {Frontiers in microbiology}, volume = {11}, journal = {Frontiers in microbiology}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {1664-302X}, doi = {10.3389/fmicb.2020.510638}, pages = {12}, year = {2020}, abstract = {Bacteriophages use a large number of different bacterial cell envelope structures as receptors for surface attachment. As a consequence, bacterial surfaces represent a major control point for the defense against phage attack. One strategy for phage population control is the production of outer membrane vesicles (OMVs). In Gram-negative host bacteria, O-antigen-specific bacteriophages address lipopolysaccharide (LPS) to initiate infection, thus relying on an essential outer membrane glycan building block as receptor that is constantly present also in OMVs. In this work, we have analyzed interactions ofSalmonella(S.) bacteriophage P22 with OMVs. For this, we isolated OMVs that were formed in large amounts during mechanical cell lysis of the P22 S. Typhimurium host.In vitro, these OMVs could efficiently reduce the number of infective phage particles. Fluorescence spectroscopy showed that upon interaction with OMVs, bacteriophage P22 released its DNA into the vesicle lumen. However, only about one third of the phage P22 particles actively ejected their genome. For the larger part, no genome release was observed, albeit the majority of phages in the system had lost infectivity towards their host. With OMVs, P22 ejected its DNA more rapidly and could release more DNA against elevated osmotic pressures compared to DNA release triggered with protein-free LPS aggregates. This emphasizes that OMV composition is a key feature for the regulation of infective bacteriophage particles in the system.}, language = {en} } @article{SzaboGrafeKemperetal.2017, author = {Szabo, Istvan and Grafe, Marianne and Kemper, Nicole and Junker, Ernst and Malorny, Burkhard}, title = {Genetic basis for loss of immuno-reactive O-chain in Salmonella enterica serovar Enteritidis veterinary isolates}, series = {Veterinary microbiology}, volume = {204}, journal = {Veterinary microbiology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0378-1135}, doi = {10.1016/j.vetmic.2017.03.033}, pages = {165 -- 173}, year = {2017}, abstract = {Fifty-two rough Salmonella enterica serovar Enteritidis (S. Enteritidis) isolates from broilers and the environment were characterized for their serological and genotypic properties. Under routine diagnostic serotyping methods such isolates lack the immuno-reactivity of the O-chain of the lipopolysaccharide (LPS), and are referred to as non-typeable. Using a modified slide agglutination method, the isolates could be differentiated into three different serological variants. Twenty-six isolates (50\%) were defined as semi-rough, nineteen isolates (37\%) as deep-rough, four isolates (8\%) as rough and three isolates could not be assigned. Genetically, all semi-rough isolates lacked the wzyB gene encoding the O-antigen polymerase. Two isolates carried a frameshift mutation in wzyB. In 15 of 23 cases deep-rough or rough isolates had a single point mutation, a single- or double-nucleotide insert or deletion in the wbaP gene. The mutational changes lead to expression of truncated (premature) protein, resulting in the loss of the immuno-reactive O-chain. Both rough and smooth S. Enteritidis isolates showed identical or highly similar XbaI-PFGE profiles. Our results indicate that the loss of a functional LPS in S. Enteritidis isolates is caused by a variety of different mutation events within the wzyB (semi-rough) or the wbaP (deep-rough) gene and is not a result of a vertical spread of a specific S. Enteritidis subtype. The defect of the LPS may be a common evolutionary mechanism through which host defence can be escaped.}, language = {en} }