Michael G Schmidt

Medical University of South Carolina | MUSC · Department of Microbiology and Immunology (College of Medicine)

Context: Recurrent caries are the leading cause of composite resin failure. Aims: The purpose of this pilot study was to test the efficacy of a novel copper iodide (CuI) containing dental adhesive in an in vitro caries model. Subjects and methods: Streptococcus mutans and Lactobacillus acidophilus were grown individually on the complex medium...

Despite cleaning efforts of environmental service teams and substantial compliance with hand hygiene best practices, the microbial burden in patient care settings often exceeds concentrations at which transfer to patients represents a substantial acquisition risk for health care-associated infections (HAIs). Approaches to limit HAI risk have relied...

Microbial bioburden associated with the built environment can impact the rate of health care–associated infection acquisition; higher bioburden results in a greater incidence of health care–associated infections. Two disinfectants registered by the US Environmental Protection Agency and a trial disinfectant were evaluated for their ability to limit...

Background CRE have emerged as a significant cause of healthcare associated infections (HAI) resulting in significant morbidity and mortality. Identification of CRE colonized and/or infected patients early during care enables implementation of comprehensive infection control measures that limit spread and likely reduce the risk of CRE mediated HAI....

Background: Stethoscopes may serve as vehicles for transmission of bacteria among patients. The aim of this study was to assess the efficacy of antimicrobial copper surfaces to reduce the bacterial concentration associated with stethoscope surfaces. Methods: A structured prospective trial involving 21 health care providers was conducted at a ped...

Objectives This study investigated the antibacterial properties and micro-hardness of polyacrylic acid (PAA)-coated copper iodide (CuI) nanoparticles incorporated into glass ionomer-based materials, and the effect of PAA-CuI on collagen degradation. Materials and methods PAA-CuI nanoparticles were incorporated into glass ionomer (GI), Ionofil Molar...

Objective: To assess the ability of copper alloy surfaces to mitigate the bacterial burden associated with commonly touched surfaces in conjunction with daily and terminal cleaning in rural hospital settings. Design: A prospective intention-to-treat trial design was used to evaluate the effectiveness of cooper alloy surfaces and respective contr...

Background: Studies have consistently shown that copper alloyed surfaces decrease the burden of microorganisms in health care environments. This study assessed whether copper alloy surfaces decreased hospital-associated infections in pediatric intensive and intermediate care units. Methods: Admitted infants were assigned sequentially to a room f...

Antibiotic resistance is a growing threat to human health exacerbated by a lack of new antibiotics. We now describe a series of substituted diamines that produce rapid bactericidal activity against both Gram-positive and Gram-negative bacteria, including methicillin-resistant Staphylococcus aureus and stationary-phase bacteria. These compounds redu...

Background: Health care-associated infections result in significant patient morbidity and mortality. Although cleaning can remove pathogens present on hospital surfaces, those surfaces may be inadequately cleaned or recontaminated within minutes. Because of copper's inherent and continuous antimicrobial properties, copper surfaces offer a solution...

This is a translational science article that discusses copper alloys as antimicrobial environmental surfaces. Bacteria die when they come in contact with copper alloys in laboratory tests. Components made of copper alloys were also found to be efficacious in a clinical trial. There are indications that bacteria found on frequently touched environme...

Provided are antibacterial and antimicrobial surface coatings and dental materials by utilizing the antimicrobial properties of copper chalcogenide and/or copper halide (CuQ, where Q=chalcogens including oxygen, or halogens, or nothing). An antimicrobial barrier is created by incorporation of CuQ nanoparticles of an appropriate size and at a concen...

Steatotic livers are more sensitive to ischemia/reperfusion (I/R) and are thus routinely rejected for transplantation because of their increased rate of primary nonfunction (PNF). Lean livers have less I/R-induced damage and inflammation due to Kupffer cells (KC), which are protective after total, warm, hepatic I/R with associated bowel congestion....

For more than a century, healthcare has been challenged to keep environmental surfaces clean to control microbes and improve patient outcomes. However despite an annual cost exceeding ten billion dollars cleaning with disinfection has done little to reduce the incidence of healthcare-associated infections (HAI). This chapter will review the scienti...

Abstract Uncoupling protein 2 (UCP2) is a mitochondrial membrane protein that regulates energy metabolism and reactive oxygen species (ROS) production. We generated mouse carboxy- and amino-terminal green fluorescent protein (GFP)-tagged UCP2 constructs to investigate the effect of UCP2 expression on cell proliferation and viability. UCP2-transfect...

Fatty liver or hepatic steatosis is a common health problem associated with abnormal liver function and increased susceptibility to ischemia/reperfusion injury. The objective of this study was to investigate the effect of the fatty acid synthase inhibitor cerulenin on hepatic function in steatotic ob/ob mice. Different dosages of cerulenin were adm...

Objective Healthcare-acquired infections (HAIs) cause substantial patient morbidity and mortality. Items in the environment harbor microorganisms that may contribute to HAIs. Reduction in surface bioburden may be an effective strategy to reduce HAIs. The inherent biocidal properties of copper surfaces offer a theoretical advantage to conventional c...

Cleaning is an effective way to lower the bacterial burden (BB) on surfaces and minimize the infection risk to patients. However, BB can quickly return. Copper, when used to surface hospital bed rails, was found to consistently limit surface BB before and after cleaning through its continuous antimicrobial activity.

Colonization of HVAC systems by microbes may lead to release of hazardous bioaerosols containing allergens, irritants, odorants, or infectious agents to indoor air, possibly adversely affecting system performance. Unlike the many common materials used in HVAC systems, copper and copper alloys have been shown in laboratory investigations to kill bac...

Microbial growth in heating ventilation and air-conditioning (HVAC) systems with the subsequent contamination of indoor air is of increasing concern. Microbes and the subsequent biofilms grow easily within heat exchangers. A comparative study where heat exchangers fabricated from antimicrobial copper were evaluated for their ability to limit microb...

The contribution of environmental surface contamination with pathogenic organisms to the development of health care-associated infections (HAI) has not been well defined. The microbial burden (MB) associated with commonly touched surfaces in intensive care units (ICUs) was determined by sampling six objects in 16 rooms in ICUs in three hospitals ov...

Background: Commonly touched items are likely reservoirs from which patients, health care workers, and visitors may encounter and transfer microbes. A quantitative assessment was conducted of the risk represented by the intrinsic bacterial burden associated with bed rails in a medical intensive care unit (MICU), and how disinfection might mitigate...

Steatotic livers are sensitive to ischemic events and associated ATP depletion. Hepatocellular necrosis following these events may result from mitochondrial uncoupling protein-2 (UCP2) expression. To test this hypothesis, we developed a model of in vitro steatosis using primary hepatocytes from wild-type (WT) and UCP2 knockout (KO) mice and subject...

Background: HAIs result in significant patient (pt) morbidity and mortality. Environmental surfaces are known to harbor microorganisms; however the contribution of surface contamination to HAIs has not been well defined. Previously we reported that CuS reduced the median environmental bioburden by 97% compared to non-copper surfaces in MICU pt room...

Effective cleaning of the patient environment has been advocated to reduce the risk for nosocomial infection. This pilot study compared 2 terminal cleaning methods, a traditional method in which a disinfectant was applied with a wetted cloth and an alternative method in which the disinfectant was applied using the PureMist system (PureCart Systems,...

Hospitals clean environmental surfaces to lower microbial contamination and reduce the likelihood of transmitting infections. Despite current cleaning and hand hygiene protocols, hospital-acquired infections (HAIs) continue to result in a significant loss of life and cost the U.S. healthcare system an estimated $45 billion annually. Stainless steel...

Kupffer cells (KCs) have been shown to be critical mediators of ischemia/reperfusion (I/R) injury in the murine liver. Using liposomal clodronate (LC), we found that KCs were protective in models of total hepatic ischemia with bowel congestion. We investigated the role of toll-like receptor 4 (TLR4) in the damage that occurs after I/R in KC-deplete...

The acquisition of microbes with the subsequent development of an infection while hospitalized continues to challenge healthcare worldwide. The CDC estimates the overall risk, mortality and cost to the USA to be ~5%, 100,000 deaths and ~45 billion additional dollars; rates for Medical Intensive Care Units (MICU) are higher where the risk often exce...

In densely occupied buildings, airborne microbial contaminants can have numerous adverse effects on human health and wellbeing, including inflammation and infections. The goal of this project was to test copper, a known anti-microbial material, for reducing colonization of HVAC systems and improving indoor air quality. At Fort Jackson, an Army trai...

Kupffer cells (KCs) are thought to mediate hepatocyte injury via their production of proinflammatory cytokines and reactive oxygen species in response to stress. In this study, we depleted KCs from the liver to examine their role in total warm hepatic ischemia/reperfusion (I/R) injury with bowel congestion. We injected 8-wk-old C57BL/10J mice with...

Background: The roles of the neither the environment for transmission of microbes in hospitals, nor the effectiveness of measures to reduce the MB in the patient care environment have been adequately described. Objective: To conduct a pilot study to assess the ability of copper to reduce the MB associated with objects in the patient care environm...

We have previously shown that treatment of steatotic livers with vitamin E succinate decreases liver injury and increases survival after ischemia/reperfusion (I/R). It is now understood that compromised energy status is associated with increased injury following liver ischemia in the setting of hepatic steatosis at least partially as a result of in...

Steatotic donors are routinely rejected for transplantation because of their increased rate of primary nonfunction. These grafts are more sensitive to ischemia/reperfusion (I/R) during transplantation. Removal of endotoxin before reperfusion improves liver performance post-I/R. We hypothesize that the main modality of injury in steatotic livers is...

Steatotic livers represent a growing proportion of marginal organs available for transplantation. These livers are highly prone to primary nonfunction following transplantation and are therefore routinely turned down for surgery. Given the elevated levels and sensitivity for reactive oxygen species (ROS) in these livers, we evaluated whether pretre...

Background: The role of the environment for microbe transmission in hospitals has not been adequately described. Methods: Obs (bed rails, overbed tray, chairs, call button, data device, & IV pole) in randomly selected ICU rms in 3 hospitals (A, B & C) were sampled by sterile wipes and the MB determined as colony forming units (cfu)/100cm2. The MB o...

Hormonal resuscitation, specifically administration of levothyroxine (T4) and methylprednisolone (steroid, i.e., the "T4 Protocol") in organ transplant donors, is becoming increasingly used. Previous studies have shown that this maximizes the number of usable organs by reducing metabolic disturbances post-brain death. However, anecdotal evidence ha...

Steatotic livers are not used for transplantation because they have a reduced tolerance for ischemic events with reduced ATP levels and greater levels of cellular necrosis, which ultimately result in total organ failure. Mitochondrial uncoupling protein-2 (UCP2) is highly expressed in steatotic livers and may be responsible for liver sensitivity to...

Hepatic steatosis increases the extent of cellular injury incurred during ischemia/reperfusion (I/R) injury. (-)-Epigallocatechin gallate (EGCG), the major flavonoid component of green tea (camellia sinensis) is a potent antioxidant that inhibits fatty acid synthase (FAS) in vitro. We investigated the effects of EGCG on hepatic steatosis and marker...

Steatosis significantly contributes to an organ's transplantability. Livers with >30% fat content have a 25% chance of developing primary non-function (PNF). The current practice of evaluating a hematoxylin and eosin (H&E) stained donor biopsy by visual interpretation is subjective. We hypothesized that H&E staining of frozen sections fails to accu...

Steatotic mice are particularly susceptible to hepatic ischemia/reperfusion injury compared with their lean littermates. We have previously demonstrated that livers of mice having a spontaneous mutation in the leptin gene (ob/ob), resulting in global obesity and liver steatosis, are ATP depleted, are endotoxin sensitive, and do not survive (I/R) in...

Cerulenin has been shown to reduce body weight and hepatic steatosis in murine models of obesity by inhibiting fatty acid synthase (FAS). We have shown that attenuating intrahepatocyte lipid content diminished the sensitivity of ob/ob mice to ischemia/reperfusion injury and improved survival after liver transplantation. The mechanism of action is b...

The number of patients requiring organ transplants still outpaces the number of available transplantable organs. During the process of orthotopic liver transplantation (OLTx), donor organs undergo significant stress resulting from ischemia and reperfusion. Healthy organs respond to this stressful environment with compensatory mechanisms that ideall...

The number of potential donor organs deemed suboptimal for transplantation because of hepatic steatosis is rising as the obesity rate increases. However, no mouse transplant model has been described within the framework of hepatic steatosis. We describe the development of and our initial experience with a steatotic mouse orthotopic liver transplant...

Mitochondrial uncoupling protein 2 (UCP2) plays an important role in regulating energy metabolism. We previously reported that UCP2 expression in steatotic livers is increased which leads to diminished hepatic ATP stores and renders steatotic hepatocytes vulnerable to ischemic damage. In this study, reagents that inhibit the production of ATP were...

The possibility of appearance of GUT precursors near the TeV scale (suggested by Dienes-Dudas-Gherghetta) is addressed within 5D GUTs compactified on an S(1)/Z2×Z2' orbifold. For a low compactification scale (large radius), there is a significant non-universal logarithmic contribution in the relative running of gauge couplings. This within 5D /SU(5...

The continuum World Line Formalism permits a transparent discussion of bosonic and fermionic determinants in some background field. For general, nontrivial backgrounds numerical evaluations must be envisaged. In this work we implement this formalism on the lattice by using statistically generated random walk world line loops. We illustrate the meth...

Selectively regulating gene expression is an essential molecular tool that is lacking for many pathogenic gram-positive bacteria. In this report, we describe the evaluation of a series of promoters regulated by the bacteriophage P1 temperature-sensitive C1 repressor in Enterococcus faecium, Enterococcus faecalis, and Staphylococcus aureus. Using th...

The emergence and increasing prevalence of multidrug-resistant bacterial pathogens emphasizes the need for new and innovative antimicrobial strategies. Lytic phages, which kill their host following amplification and release of progeny phage into the environment, may offer an alternative strategy for combating bacterial infections. In this study, ho...

In this report we describe the development of a highly stringent and dually regulated promoter system for Shigella flexneri. Dual regulation was provided by utilizing a promoter susceptible to control by the bacteriophage P1 temperature-sensitive C1 repressor that in turn was under the transcriptional control of LacI. The level of induction/repress...

A co-culture of two Pseudomonas putida isolates was enriched from sediment on a mixture of benzene, toluene, ethylbenzene, m-xylene, p-xylene, and o-xylene. The co-culture readily degraded each of the compounds present. Benzene, toluene, and ethylbenzene were used as growth substrates by one isolate, while toluene, m-xylene, and p-xylene were used...