Bacterial Infections and Mycoses Commons^™

Nanosecond Pulsed Electric Fields Increase Antibiotic Susceptibility In Methicillin-Resistant Staphylococcus Aureus, Alexandra E. Chittams-Miles, Areej Malik, Erin B. Purcell, Claudia Muratori

Bioelectrics Publications

Staphylococcus aureus is the leading cause of skin and soft-tissue infections (SSTIs). SSTIs caused by bacteria resistant to antimicrobials, such as methicillin-resistant S. aureus (MRSA), are increasing in incidence and have led to higher rates of hospitalization. In this study, we measured MRSA inactivation by nanosecond pulsed electric fields (nsPEF), a promising new cell ablation technology. Our results show that treatment with 120 pulses of 600 ns duration (28 kV/cm, 1 Hz), caused modest inactivation, indicating cellular damage. We anticipated that the perturbation created by nsPEF could increase antibiotic efficacy if nsPEF were applied as a co-treatment. To test this …

Predominantly Methicillin-Susceptible S. Aureus Bacteria Found In Csp Students’ S. Aureus Strains, Roma Ambo

Research and Scholarship Symposium Posters

Positive Staphylococcus aureus strains from CSP students were tested for methicillin resistance (MRSA) using the Kirby-bauer assay. Kirby-bauer assay technique was used to determine the sensitivity of staphylococcus aureus bacteria against oxacillin. MRSA infection is the result of a bacteria that has built resistance against the antibiotics used to treat staph infections. The results of this experiment concludes that majority of the strains tested are methicillin-susceptible S. aureus (MSSA).

Chrysin‐Loaded Chitosan Nanoparticles Potentiates Antibiofilm Activity Against Staphylococcus Aureus, Busi Siddhardha, Uday Pandey, K. Kaviyarasu, Rajasekharreddy Pala, Asad Syed, Ali K. Bahkali, Abdallah M. Elgorban

Pharmacy Faculty Articles and Research

The application of nanotechnology in medicine is gaining popularity due to its ability to increase the bioavailability and biosorption of numerous drugs. Chrysin, a flavone constituent of Orocylumineicum vent is well‐reported for its biological properties. However, its therapeutic potential has not been fully exploited due to its poor solubility and bioavailability. In the present study, chrysin was encapsulated into chitosan nanoparticles using TPP as a linker. The nanoparticles were characterized and investigated for their anti‐biofilm activity against Staphylococcus aureus. At sub‐Minimum Inhibitory Concentration, the nanoparticles exhibited enhanced anti‐biofilm efficacy against S. aureus as compared to its bulk counterparts, chrysin …

Gas Plasma Pre-Treatment Increases Antibiotic Sensitivity And Persister Eradication In Methicillin-Resistant Staphylococcus Aureus, Li Guo, Ruobing Xu, Yiming Zhao, Dingxin Liu, Zhijie Liu, Xiaohua Wang, Hailan Chen, Michael G. Kong

Bioelectrics Publications

Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of serious nosocomial infections, and recurrent MRSA infections primarily result from the survival of persister cells after antibiotic treatment. Gas plasma, a novel source of ROS (reactive oxygen species) and RNS (reactive nitrogen species) generation, not only inactivates pathogenic microbes but also restore the sensitivity of MRSA to antibiotics. This study further found that sublethal treatment of MRSA with both plasma and plasma-activated saline increased the antibiotic sensitivity and promoted the eradication of persister cells by tetracycline, gentamycin, clindamycin, chloramphenicol, ciprofloxacin, rifampicin, and vancomycin. The short-lived ROS and RNS generated by plasma …

Prevalence Of Nasal Colonization By Methicillin-Resistant Staphylococcus Aureus In Persons Using A Homeless Shelter In Kansas City, Megan Ottomeyer, Charles D. Graham, Avery D. Legg, Elizabeth S. Cooper, Chad D. Law, Mariam Molani, Karine Matevossian, Jerry Marlin, Charlott Williams, Ramon Newman, Jason A. Wasserman, Larry W. Segars, Tracey A H Taylor

Manuscripts, Articles, Book Chapters and Other Papers

Nasal colonization of methicillin-resistant Staphylococcus aureus (MRSA) plays an important role in the epidemiology and pathogenesis of disease. Situations of close-quarter contact in groups are generally regarded as a risk factor for community-acquired MRSA strains due to transmission via fomites and person-to-person contact. With these criteria for risk, homeless individuals using shelter facilities, including showers and toilets, should be considered high risk for colonization and infection. The aim of this study was to determine the prevalence of nasal colonization of MRSA in a homeless population compared to established rates of colonization within the public and a control group of subjects …

The Genesis And Emergence Of Community-Associated Methicillin-Resistant Staphylococcus Aureus (Ca-Mrsa): An Example Of Evolution In Action?, Alan L. Gillen, Jason Conrad, Michael Cargill

Faculty Publications and Presentations

Staphylococcus aureus infections are a common cause of disease, particularly in colonized persons. Recently, a series of published articles have reported that community-acquired methicillin-resistant S. aureus (CA-MRSA) strains are evolving and increasingly becoming prevalent in households while health care acquired MRSA (HA-MRSA) is declining in the USA. The changing superbugs have often been used as an example of evolution in action. Although MRSA infections have become increasingly reported in the community, population-based studies of students preparing for the health professions having S. aureus and MRSA colonization are lacking. During the 2014–2015 school year 544 students were tested for MRSA carriage …

Simultaneous Bactericidal And Osteogenic Effect Of Nanoparticulate Calcium Phosphate Powders Loaded With Clindamycin On Osteoblasts Infected With Staphylococcus Aureus, Vuk Uskoković, Tejal A. Dasai

Pharmacy Faculty Articles and Research

S aureus internalized by bone cells and shielded from the immune system provides a reservoir of bacteria in recurring osteomyelitis. Its targeting by the antibiotic therapy may thus be more relevant for treating chronic bone infection than eliminating only the pathogens colonizing the bone matrix. Assessed was the combined osteogenic and antibacterial effect of clindamycinloaded calcium phosphate nanoparticles of different monophasic compositions on co-cultures comprising osteoblasts infected with S aureus. Antibiotic-carrying particles were internalized by osteoblasts and minimized the concentration of intracellular bacteria. In vitro treatments of the infected cells, however, could not prevent cell necrosis due to the …

Osteogenic And Antimicrobial Nanoparticulate Calcium Phosphate And Poly-(D, L-Lactide-Co-Glycolide) Powders For The Treatment Of Osteomyelitis, Vuk Uskoković, Charles Hoover, Marija Vukomanović, Dragan P. Uskoković, Tejal A. Dasai, Charles Hoover, Marija Vukomanović, Dragan P. Uskoković, Tejal A. Dasai

Pharmacy Faculty Articles and Research

Development of a material for simultaneous sustained and localized delivery of antibiotics and induction of spontaneous regeneration of hard tissues affected by osteomyelitis stands for an important clinical need. In this work, a comparative analysis of the bacterial and osteoblastic cell response to two different nanoparticulate carriers of clindamycin, an antibiotic commonly prescribed in the treatment of bone infection, one composed of calcium phosphate and the other comprising poly-(D,L-lactide-co-glycolide)-coated calcium phosphate, was carried out. Three different non-cytotoxic phases of calcium phosphate, exhibiting dissolution and drug release profiles in the range of one week to two months to one year, respectively, …

Β-Lactams Interfering With Pbp1 Induce Panton-Valentine Leukocidin Expression By Triggering Sara And Rot Global Regulators Of Staphylococcus Aureus, Oana Dumitrescu, Priya Choudhury, Sandrine Boisset, Cedric Badiou, Michele Bes, Yvonne Benito, Christiane Wolz, Francois Vandenesch, Jerome Etienne, Ambrose L. Cheung

Dartmouth Scholarship

Previous articles reported that beta-lactam antibiotics increase the expression of Staphylococcus aureus Panton-Valentine leukocidin (PVL) by activating its transcription. We investigated the mechanisms underlying the inductor effect of beta-lactams on PVL expression by determining targets and regulatory pathways possibly implicated in this process. We measured PVL production in the presence of oxacillin (nonselective), imipenem (penicillin-binding protein 1 [PBP1] selective), cefotaxime (PBP2 s

Tca Cycle Inactivation In Staphylococcus Aureus Alters Nitric Oxide Production In Raw 264.7 Cells, Chandirasegaran Massilamany, Arunakumar Gangaplara, Donald J. Gardner, James M. Musser, David J. Steffen, Greg A. Somerville, Jay Reddy

Jay Reddy Publications

Inactivation of the Staphylococcus aureus tricarboxylic acid (TCA) cycle delays the resolution of cutaneous ulcers in a mouse soft tissue infection model. In this study, it was observed that cutaneous lesions in mice infected with wild-type or isogenic aconitase mutant S. aureus strains contained comparable inflammatory infiltrates, suggesting the delayed resolution was independent of the recruitment of immune cells. These observations led us to hypothesize that staphylococcal metabolism can modulate the host immune response. Using an in vitro model system involving RAW 264.7 cells, the authors observed that cells cultured with S. aureus aconitase mutant strains produced significantly lower amounts …

Rapid Emergence Of Co-Colonization With Community-Acquired And Hospital-Acquired Methicillin-Resistant Staphylococcus Aureus Strains In The Hospital Setting, Joanna R. Wares, Erika M.C. D'Agata, Glenn F. Webb

Department of Math & Statistics Faculty Publications

Background: Community-acquired methicillin-resistant Staphylococcus aureus (CAMRSA), a novel strain of MRSA, has recently emerged and rapidly spread in the community. Invasion into the hospital setting with replacement of the hospital-acquired MRSA (HA-MRSA) has also been documented. Co-colonization with both CA-MRSA and HA-MRSA would have important clinical implications given differences in antimicrobial susceptibility profiles and the potential for exchange of genetic information.

Methods: A deterministic mathematical model was developed to characterize the transmission dynamics of HA-MRSA and CA-MRSA in the hospital setting and to quantify the emergence of co-colonization with both strains Results: The model analysis shows that the …