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antibiotic resistance and biofilm formation

Ahmed Abdel Megeed, M Ali Hayssam, Mohamed Z M Salem, Mohamed S El-Shikh, Ibrahim Ahmed Talea, Yahya A Alogaibi
Multidrug-resistant (MDR) Acinetobacter baumannii infections are a great public health concern and demand continuous surveillance and antibiotic stewardship. Virulence traits and the pathogenicity of Acinetobacter are less studied compared with the molecular epidemiological and antibiotic resistance profile of this organism. In our present study, we investigated the primary characteristics contributing to the virulence of MDR A. baumannii isolates and compared them with avirulent isolates. A total of 32 well-characterized MDR A...
October 19, 2016: Journal of AOAC International
Dharmaprakash Viszwapriya, Ganapathy Ashwinkumar Subramenium, Solai Radhika, Shunmugiah Karutha Pandian
Streptococcus mutans, a multivirulent pathogen is considered the primary etiological agent in dental caries. Development of antibiotic resistance in the pathogen has created a need for novel antagonistic agents which can control the virulence of the organism and reduce resistance development. The present study demonstrates the in vitro anti-virulence potential of betulin (lup-20(29)-ene-3β,28-diol), an abundantly available plant triterpenoid against S. mutans UA159. Betulin exhibited significant dose dependent antibiofilm activity without affecting bacterial viability...
October 18, 2016: Antonie Van Leeuwenhoek
Arianna Pompilio, Valentina Crocetta, Dipankar Ghosh, Malabika Chakrabarti, Giovanni Gherardi, Luca Agostino Vitali, Ersilia Fiscarelli, Giovanni Di Bonaventura
The present study was carried out to understand the adaptive strategies developed by Stenotrophomonas maltophilia for chronic colonization of the cystic fibrosis (CF) lung. For this purpose, 13 temporally isolated strains from a single CF patient chronically infected over a 10-year period were systematically characterized for growth rate, biofilm formation, motility, mutation frequencies, antibiotic resistance, and pathogenicity. Pulsed-field gel electrophoresis (PFGE) showed over time the presence of two distinct groups, each consisting of two different pulsotypes...
2016: Frontiers in Microbiology
Zahid Iqbal, Mohamed N Seleem, Hafiz Iftikhar Hussain, Lingli Huang, Haihong Hao, Zonghui Yuan
Several studies have been conducted to check the prevalence of methicillin-resistant strains of Staphylococcus aureus (MRSA) in animals and animal-derived food products but limited data are available regarding their virulence and associated gene expression profile. In the present study, antibiotic resistance and virulence of MRSA and methicillin-sensitive S. aureus animal isolates were determined in vitro by agar dilution, biofilm formation, adhesion, invasion and intracellular survivability assays. In addition, the pathogenicity of these isolates was examined in a murine model of S...
October 14, 2016: Scientific Reports
Maren Seitz, Peter Valentin-Weigand, Jörg Willenborg
Use of antimicrobial agents in veterinary medicine is essential to control infectious diseases, thereby keeping animals healthy and animal products safe for the consumer. On the other hand, development and spread of antimicrobial resistance is of major concern for public health. Streptococcus (S.) suis reflects a typical bacterial pathogen in modern swine production due to its facultative pathogenic nature and wide spread in the pig population. Thus, in the present review we focus on certain current aspects and problems related to antimicrobial use and resistance in S...
October 15, 2016: Current Topics in Microbiology and Immunology
Andreas Thomann, Christian Brengel, Carsten Börger, Dagmar Kail, Anke Steinbach, Martin Empting, Rolf W Hartmann
Drug-resistant Pseudomonas aeruginosa (PA) strains are on the rise, making treatment with current antibiotics ineffective. Hence, circumventing resistance or restoring the activity of antibiotics by novel approaches is of high demand. Targeting the Pseudomonas quinolone signal quorum sensing (PQS-QS) system is an intriguing strategy to abolish PA pathogenicity without affecting the viability of the pathogen. Herein we report the structure-activity relationships of 2-sulfonylpyrimidines, which were previously identified as dual-target inhibitors of the PQS receptor PqsR and the PQS synthase PqsD...
October 12, 2016: ChemMedChem
W Kram, N Buchholz, O W Hakenberg
Ureteral stents are the most commonly used urological implants. They are used for temporary as well as for long-term ureteral stenting. Amongst others, complications of ureteral stenting are encrustation and cellular adherence which, in turn, promotes urinary tract infection and can induce impaired healing in case of ureteral damage. Biofilm formation on urological implants leads to the protection of persisting bacteria from local defense mechanisms, thereby rendering persistent urinary tract infections more common...
October 2016: Archivos Españoles de Urología
Enea G Di Domenico, Luigi Toma, Christian Provot, Fiorentina Ascenzioni, Isabella Sperduti, Grazia Prignano, Maria T Gallo, Fulvia Pimpinelli, Valentina Bordignon, Thierry Bernardi, Fabrizio Ensoli
Microbial biofilm represents a major virulence factor associated with chronic and recurrent infections. Pathogenic bacteria embedded in biofilms are highly resistant to environmental and chemical agents, including antibiotics and therefore difficult to eradicate. Thus, reliable tests to assess biofilm formation by bacterial strains as well as the impact of chemicals or antibiotics on biofilm formation represent desirable tools for a most effective therapeutic management and microbiological risk control. Current methods to evaluate biofilm formation are usually time-consuming, costly, and hardly applicable in the clinical setting...
2016: Frontiers in Microbiology
Nopphasul Sirijant, Rasana W Sermswan, Surasakdi Wongratanacheewin
Burkholderia pseudomallei, the causative agent of melioidosis, has been found to increase its resistance to antibiotics when growing as a biofilm. The resistances are related to several mechanisms. One of the possible mechanisms is the efflux pump. Using bioinformatics analysis, it was found that BPSL1661, BPSL1664 and BPSL1665 were orthologous genes of the efflux transporter encoding genes for biofilm related antibiotic resistance PA1874-PA1877 genes in Pseudomonas aeruginosa strain PAO1. Expressions of selected encoding genes for the efflux transporter system during biofilm formation were investigated...
September 30, 2016: Journal of Medical Microbiology
Josué Flores-Kim, Andrew J Darwin
: The Phage shock protein (Psp) system is a widely conserved cell envelope stress response that is essential for the virulence of some bacteria, including Yersinia enterocolitica Recruitment of PspA by the inner membrane PspB•PspC complex characterizes the activated state of this response. The PspB•PspC complex has been proposed to be a stress-responsive switch, changing from an OFF to an ON state in response to an inducing stimulus. In the OFF state, PspA cannot access its binding site in the C-terminal cytoplasmic domain of PspC (PspC(CT)) because this site is bound to PspB...
October 3, 2016: Journal of Bacteriology
Maira P de Carvalho, Giuseppe Gulotta, Matheus W do Amaral, Heinrich Lünsdorf, Florenz Sasse, Wolf-Rainer Abraham
Pathogens embedded in biofilms are involved in many infections and are very difficult to treat with antibiotics because of higher resistance compared to planktonic cells. Therefore, new approaches for their control are urgently needed. One way to search for biofilm dispersing compounds is to look at defense strategies of organisms exposed to wet environments, which makes them prone to biofilm infections. It is reasonable to assume that mushrooms have developed mechanisms to control biofilms on their sporocarps (fruiting bodies)...
October 3, 2016: Environmental Microbiology
Cristiana Pontes, Marta Alves, Catarina Santos, Maria H Ribeiro, Lídia Gonçalves, Ana F Bettencourt, Isabel A C Ribeiro
Given the impact of biofilms in health care environment and the increasing antibiotic resistance and/or tolerance, new strategies for preventing that occurrence in medical devices are obligatory. Thus, biomaterials surface functionalization with active compounds can be a valuable approach. In the present study the ability of the biosurfactants sophorolipids to prevent biofilms formation on silicone rubber aimed for medical catheters was investigated. Sophorolipids produced by Starmerella bombicola, identified by HPLC-MS/MS were used to cover silicone and surface characterization was evaluated through contact angle measurements and FTIR-ATR...
September 28, 2016: International Journal of Pharmaceutics
Nis Pedersen Jørgensen, Natalia Zobek, Cindy Dreier, Jakob Haaber, Hanne Ingmer, Ole Halfdan Larsen, Rikke L Meyer
Biofilms formed by Staphylococcus aureus is a serious complication to the use of medical implants. A central part of the pathogenesis relies on S. aureus' ability to adhere to host extracellular matrix proteins, which adsorb to medical implants and stimulate biofilm formation. Being coagulase positive, S. aureus furthermore induces formation of fibrin fibers from fibrinogen in the blood. Consequently, we hypothesized that fibrin is a key component of the extracellular matrix of S. aureus biofilms under in vivo conditions, and that the recalcitrance of biofilm infections can be overcome by combining antibiotic treatment with a fibrinolytic drug...
September 20, 2016: Microorganisms
Signe M Nielsen, Niels Nørskov-Lauritsen, Thomas Bjarnsholt, Rikke L Meyer
Achromobacter species have attracted attention as emerging pathogens in cystic fibrosis. The clinical significance of Achromobacter infection is not yet fully elucidated; however, their intrinsic resistance to antimicrobials and ability to form biofilms renders them capable of establishing long-term chronic infections. Still, many aspects of Achromobacter biofilm formation remain uncharacterized. In this study, we characterized biofilm formation in clinical isolates of Achromobacter and investigated the effect of challenging the biofilm with antimicrobials and/or enzymes targeting the extracellular matrix...
September 14, 2016: Microorganisms
Sandhya Nair, Srividya Desai, Nethravathi Poonacha, Aradhana Vipra, Umender Sharma
P128 is an anti-staphylococcal protein comprising a cell wall-degrading enzymatic region and a Staphylococcus-specific binding region, which possesses specific and potent bactericidal activity against sensitive and drug resistant strains of S. aureus To explore P128's ability to kill S. aureus in a range of environments relevant to clinical infection, we investigated the anti-S. aureus activity of P128 alone and in combination with the standard of care antibiotics on planktonic and biofilm-embedded cells. P128 was found to have potent anti-biofilm activity on pre-formed S...
September 26, 2016: Antimicrobial Agents and Chemotherapy
Ekaterina V Filippova, Zdzislaw Wawrzak, Jiapeng Ruan, Sergii Pshenychnyi, Richard M Schultz, Alan J Wolfe, Wayne F Anderson
RcsB, the transcription-associated response regulator of the Rcs phosphorelay two-component signal transduction system, activates cell stress responses associated with desiccation, cell wall biosynthesis, cell division, virulence, biofilm formation and antibiotic resistance in enteric bacterial pathogens. RcsB belongs to the FixJ/NarL family of transcriptional regulators, which are characterized by a highly conserved C-terminal DNA-binding domain. The N-terminal domain of RcsB belongs to the family of two-component receiver domains...
September 27, 2016: Protein Science: a Publication of the Protein Society
Akhilesh K Chaurasia, Nanasaheb D Thorat, Anshula Tandon, Jin-Hahn Kim, Sung Ha Park, Kyeong Kyu Kim
Antibiotic resistant bacteria not only affect human health and but also threatens the safety in hospitals and among communities. However, the emergence of drug resistant bacteria is inevitable due to evolutionary selection as a consequence of indiscriminate antibiotic usage. Therefore, it is necessary to develop a novel strategy by which pathogenic bacteria can be eliminated without triggering resistance. We propose a novel magnetic nanoparticle-based physical treatment against pathogenic bacteria, which blocks biofilm formation and kills bacteria...
September 27, 2016: Scientific Reports
Masato Narita, Takahiko Shibahara, Nobuo Takano, Rie Fujii, Katsuji Okuda, Kazuyuki Ishihara
Periapical periodontitis usually results from microbial infection, with these microorganisms occasionally migrating to the root canal, which can lead to further, potentially life-threatening, complications. Here, the susceptibility of 27 bacterial strains to various antimicrobial agents was evaluated. These strains comprised 13 species; 16 of the strains were clinical isolates from periapical lesions. Each strain was inoculated onto blood agar plates containing one of the antimicrobial agents. The plates were incubated anaerobically at 37°C for 96 hr and the minimal inhibitory concentrations (MICs) determined...
2016: Bulletin of Tokyo Dental College
Pooi Yin Chung
Klebsiella pneumoniae is an opportunistic pathogen that commonly causes nosocomial infections in the urinary tract, respiratory tract, lung, wound sites and blood in individuals with debilitating diseases. Klebsiella pneumoniae is still a cause of severe pneumonia in alcoholics in Africa and Asia, and the predominant primary pathogen of primary liver abscess in Taiwan and Southeast Asia, particularly in Asian and Hispanic patients, and individuals with diabetes mellitus. In the United States and Europe, K. pneumoniae infections are most frequently associated with nosocomial infections...
October 2016: FEMS Microbiology Letters
Harrison W VanKoten, Wendy M Dlakic, Robert Engel, Mary J Cloninger
The development of pathogenic bacteria resistant to current treatments is a major issue facing the world today. Here, the synthesis and biological activity of fourth generation poly(amidoamine) dendrimers decorated with 1-hexadecyl-azoniabicylo[2.2.2]octane (C16-DABCO), a quaternary ammonium compound known to have antibacterial activity, are described. This highly cationic dendrimer antibiotic was tested against several Gram positive and Gram negative strains of pathogenic bacteria and exhibited activity against both...
October 4, 2016: Molecular Pharmaceutics
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