MRSA Infection

News: Swab Predicts MRSA-Related GI Infection

Medical News: Swab Predicts MRSA-Related GI Infection - in Meeting Coverage, DDW from MedPage Today.

SAN DIEGO -- Nasal swab testing for methicillin-resistant Staphylococcus aureus (MRSA) colonization is a strong predictor of MRSA-associated surgical site infection in gastrointestinal surgery patients, researchers said here. Surgical site infection in patients with a positive MRSA nasal swab was significantly more likely to be caused by MRSA than in patients not colonized with the resistant bacteria (70% versus 8.5%, P<0.0001), Harry Papaconstantinou, MD, and colleagues of Scott & White Memorial Hospital in Temple, Texas, reported at Digestive Disease Week.

How one strain of MRSA becomes resistant to last-line antibiotic | Science Codex

How one strain of MRSA becomes resistant to last-line antibiotic | Science Codex.

They report that vancomycin-resistant MRSA strains and other CC5 lineages have some important differences from other types of MRSA, including adaptations that allow them to co-exist with other types of bacteria and may help them take up foreign DNA. They all lack the operon called bsa, for instance, a set of genes that encode a lantibiotic bacteriocin, an antibiotic protein made by bacteria to kill other bacteria. This is important, say the authors, because it enables CC5 to get along well with other bacteria in mixed infections. Instead of killing off competing organisms, CC5 aims to co-exist. This enables it to pick up genes - like the one that encodes vancomycin resistance - from unexpected places. Mixed infections are breeding grounds for antibiotic resistance because they encourage the exchange of genes among very different kinds of organisms. In roughly the place where these bacteriocin genes are missing is a unique cluster of genes that encode enterotoxins, proteins that attack the human host and, again, could make it easier for mixed populations of bacteria to grow at infection sites. Finally, CC5 has a mutation in a gene called dprA, which is known to influence the ability to assimilate foreign DNA. The mutation could alter or eliminate the function of dprA in CC5 strains of MRSA, making it amenable to taking up DNA from outside sources.

Sublytic concentrations of Staphylococcus aureus Panton-Valentine leukocidin alter human PMN gene expression and enhance bactericidal capacity

Sublytic concentrations of Staphylococcus aureus Panton-Valentine leukocidin alter human PMN gene expression and enhance bactericidal capacity.

CA-MRSA infections are often caused by strains encoding PVL, which can cause lysis of PMNs and other myeloid cells in vitro, a function considered widely as the primary means by which PVL might contribute to disease. However, at sublytic concentrations, PVL can function as a PMN agonist. To better understand this phenomenon, we investigated the ability of PVL to alter human PMN function. PMNs exposed to PVL had enhanced capacity to produce O2− in response to fMLF, but unlike priming by LPS, this response did not require TLR signal transduction. On the other hand, there was subcellular redistribution of NADPH oxidase components in PMNs following exposure of these cells to PVL—a finding consistent with priming. Importantly, PMNs primed with PVL had an enhanced ability to bind/ingest and kill Staphylococcus aureus. Priming of PMNs with other agonists, such as IL-8 or GM-CSF, altered the ability of PVL to cause formation of pores in the plasma membranes of these cells. Microarray analysis revealed significant changes in the human PMN transcriptome following exposure to PVL, including up-regulation of molecules that regulate the inflammatory response. Consistent with the microarray data, mediators of the inflammatory response were released from PMNs after stimulation with PVL. We conclude that exposure of human PMNs to sublytic concentrations of PVL elicits a proinflammatory response that is regulated in part at the level of gene expression. We propose that PVL-mediated priming of PMNs enhances the host innate immune response.

Fitness cost: a bacteriological explanation for the demise of the first international methicillin-resistant Staphylococcus aureus epidemic

Fitness cost: a bacteriological explanation for the demise of the first international methicillin-resistant Staphylococcus aureus epidemic.

Results Significant fitness costs of 2%–15% were determined for the MRSA isolates studied. There was a significant negative correlation between number of antibiotic resistances and relative fitness. Multiple regression analysis found significantly independent negative correlations between fitness and the presence of mecA or streptomycin resistance. Mathematical modelling confirmed that fitness costs of the magnitude carried by these isolates could result in the disappearance of MRSA prevalence during a time span similar to that seen in Denmark. Conclusions We propose a significant fitness cost of resistance as the main bacteriological explanation for the disappearance of the multiresistant complex 83A MRSA in Denmark following a reduction in antibiotic usage.

Antiseptic resistance genes qacA/B and MRSA in the era of hand hygiene

Prevalence of antiseptic resistance genes qacA/B and specific sequence types of methicillin-resistant Staphylococcus aureus in the era of hand hygiene.

In an attempt to control the spread of methicillin-resistant Staphylococcus aureus (MRSA) and other multiresistant organisms in hospitalized patients, hand hygiene campaigns have promoted the widespread use of alcohol-based hand solutions containing antiseptic agents such as chlorhexidine and quaternary ammonium compounds. The use of these products, however, has led to increased resistance to these antiseptic agents in MRSA strains.1–5 qacA/B are plasmid-borne resistance genes coding for multidrug efflux pumps that confer high-level resistance to chlorhexidine, quaternary ammonium compounds and other antiseptic compounds commonly used in hand hygiene solutions.5 They are associated with higher MICs and tolerance of these antiseptic agents.1,4,5 qacA/B genes have been found in healthcare-associated MRSA (HA-MRSA) isolates from around the world.2–8 In addition, the prevalence of qacA/B genes has been associated with particular sequence types (STs) of HA-MRSA.1,3,4,6 To our knowledge, the prevalence of MRSA strains harbouring these genes has not been researched in Australia. In this study, we characterize the prevalence of qacA/B genes in HA-MRSA isolates in our institution spanning 10 years, from 2000 to 2009. We determined whether the national hand hygiene campaign implemented in 2006 had any impact on the prevalence …

Altered vancomycin pharmacokinetics in obese patients

Altered vancomycin pharmacokinetics in obese and morbidly obese patients: what we have learned over the past 30 years.

Vancomycin was the first glycopeptide antibiotic introduced into clinical practice. Despite the numerous benefits of vancomycin, clinicians have struggled to dose vancomycin successfully in obese patients to achieve a therapeutic concentration for optimal bacterial killing. Owing to the hydrophilicity of vancomycin and the increase in both adipose tissue and muscle mass associated with obesity, the volume of distribution of vancomycin in obese patients is likely to be altered compared with non-obese patients. In addition to an increase in body mass, obesity is associated with an increase in certain circulating proteins, which results in altered free serum vancomycin concentration. Another alteration that occurs in obesity is increased blood flow secondary to increased cardiac output and blood volume, resulting in increased vancomycin clearance in obese patients. Vancomycin pharmacokinetics in the obese population remain an area of much debate, one that requires continued research given the rising number of obese patients in both the USA and worldwide.

MLVF with new primer sets for Methicillin-Resistant Staphylococcus aureus.

Microfluidic chip-based Multiple-Locus Variable-Number Tandem Repeat Fingerprinting (MLVF) with new primer sets for Methicillin-Resistant Staphylococcus aureus..

MLVF is the cheapest, fastest and easiest to perform. MLVF applied to microfluidic polymer chips is a rapid, cheap, reproducible and highly discriminating tool to determine the clonality of MRSA isolates, and to trace the spread of MRSA strains over periods of many years. Although spa typing should be used due to its portability of data, MLVF has a high added-value because it is more discriminatory.

Staphylococcus aureus Protein A Polymorphic Region Regulates Inflammation: Impact on Acute and Chronic Infection

The Length of the Staphylococcus aureus Protein A Polymorphic Region Regulates Inflammation: Impact on Acute and Chronic Infection.

Staphylococcus aureus protein A (SpA) plays a critical role in the induction of inflammation. This study was aimed to determine whether the number of short sequence repeats (SSRs) present in the polymorphic region modulates the inflammatory response induced by SpA. We demonstrated that there is a dose-response effect in the activation of interferon (IFN)-β signaling in airway epithelial and immune cells, depending on the number of SSRs, which leads to differences in neutrophil recruitment. We also determined that a significant proportion of isolates from patients with chronic infections such as osteomyelitis and cystic fibrosis carry fewer SSRs than do isolates from patients with acute infections or healthy carriers and that there was an inverse correlation between the number of SSRs and the length of disease course. Given the importance of IFN signaling in eradication of S. aureus, loss of SSRs may represent an advantageous mechanism to adapt to and persist in the host.

Correlation between glove use practices and compliance with hand hygiene in a multicenter study with elderly patients

Correlation between glove use practices and compliance with hand hygiene in a multicenter study with elderly patients.

In a study conducted in 11 health care settings for elderly patients, we demonstrated a significant negative correlation between the proportion of glove use outside any risk of exposure to body fluids and compliance with hand hygiene (P < .02). This result underscores a major limitation of strategies for controlling the spread of multidrug-resistant bacteria that recommend systematic glove use for each contact with carriers or their environment.

How IBM Plans To Kill the Staph Superbug - Forbes

How IBM Plans To Kill the Staph Superbug - Forbes.

It’s an unlikely battle for a blue-chip IT company like IBM to be in the middle of, but the company may just have cracked the MRSA problem with chemical technology originally intended to… what else?… drive down the size of computer chips. “We have a broad-based program where we leverage chemistry and nanotech from years of building materials for IBM products and port them over to other realms,” explains James Hedrick, a polymer chemist in the Advanced Organic Materials division of IBM Research. Part of that program has included creating new types of polymers that have multiple potential applications. Antibiotic Stewardship in the U.S. Hedrick’s research has translated to the creation of what he calls “broad spectrum antimicrobials.” “The mechanism through which they fight bacteria is very different from the way an antibiotic works,” Hedrick says. “They try to mimic what the immune system does: the polymer attaches to the bacteria’s membrane and then facilitates destabilization of the membrane. It falls apart, everything falls out and there’s little opportunity for it to develop resistance to these polymers.”

s in a medical intensive care unit

Transmission dynamics of methicillin-resistant Staphylococcus aureus in a medical intensive care unit.

The number of all cross-transmission events increased from 54 to 72 if only patients with a past history of MRSA colonization are screened and isolated at admission, to 75 if isolation is put in place only after the results of the admission screening become available, to 82 in the absence of admission screening and with a similar reactive isolation policy, and to 95 when no isolation policy is in place. The method used (culture or polymerase chain reaction) for admission screening had no impact on the number of cross-transmissions. Systematic regular screening during ICU stay provides no added-value, but aggressive admission screening and isolation effectively reduce the number of cross-transmissions. Critically, colonized healthcare workers may play an important role in MRSA transmission and their screening should be reinforced.

Controversies in Hospital Infection Prevention: Myopic consequences

Controversies in Hospital Infection Prevention: Myopic consequences.

The May issue of American Journal of Infection Control has a survey of infection prevention programs in US hospitals assessing the impact of the CMS policy to restrict payment for hospital-acquired central line associated bloodstream infections (CLABSI), catheter associated UTI (CAUTI), and selected surgical site infections. Five hundred hospitals were randomly selected to participate and the response was 64%. While the survey contained some good news, primarily that hospitals were making efforts to get urinary and central venous catheters removed more quickly, 3 disturbing findings were uncovered:

Go to the link above for the whole article

Infection Prevention White Paper Shows Role of Environment Hygiene in Patient Safety | Quality

Infection Prevention White Paper Shows Role of Environment Hygiene in Patient Safety | Quality.

According to the white paper, approximately 20 percent to 40 percent of healthcare-associated infections have been attributed to hands of healthcare workers that have become contaminated from direct patient contact or by indirect contact with contaminated environmental surfaces. Specifically, hospital floors, bed linens and patient gowns have been shown to most frequently harbor MRSA pathogens. Environmental cleaning and disinfection is critical to the transmission of microorganisms that cause infectious diseases. The white paper also includes Crothall's integrated approach to infection prevention and control, including the training, education, supervision and ongoing competency testing of housekeeping staff.

"Supermoms against Superbugs" Take Washington by Storm - PR Newswire - The Sacramento Bee

"Supermoms against Superbugs" Take Washington by Storm - PR Newswire - The Sacramento Bee.

"Eight years ago, I lost my one-and-a-half year-old son Simon to an antibiotic-resistant infection," said Everly Macario, co-founder of the MRSA (methicillin-resistant Staphylococcus aureus) Research Center. "Every time we use an antibiotic, we risk creating a superbug. Sometimes, when people or animals are sick, we must tolerate that risk and use those drugs to fight infection. But we cannot afford to throw these drugs around industrial farms simply to rush a healthy pig or chicken to reach slaughter weight."

Editorial Commentary: Deconstructing the Veterans Affairs MRSA Prevention Bundle

Editorial Commentary: Deconstructing the Veterans Affairs MRSA Prevention Bundle.

The optimal approach to MRSA prevention in hospital settings is debated [4, 5]. In general, 2 epidemiological approaches have been described: (1) “horizontal” programs that broadly attempt to reduce infections from all pathogens and (2) “vertical” programs that aim to eradicate a single pathogen [6]. Horizontal programs include hand hygiene improvement interventions and central-line association bloodstream infection (CLABSI) “bundles.” Vertical programs screen all or selected patients for MRSA colonization by obtaining a nares swab sample and place MRSA-colonized or MRSA-infected patients on contact precautions. Contact precautions include single-bed rooms and patient cohorting and require healthcare workers to wear gowns and gloves for all contacts. Some studies reported benefits of such screening programs [7], some reported benefits when screening was combined with decolonization [8], and some found screening and isolation to be ineffective [9, 10].

Staphylococcus aureus Colonization Among Household Contacts of Patients With Skin Infections

Staphylococcus aureus Colonization Among Household Contacts of Patients With Skin Infections: Risk Factors, Strain Discordance, and Complex Ecology.

Results. We enrolled 1162 persons (350 index patients and 812 household members). The most common infection isolate characteristic was ST8/SCCmec IV, PVL+ MRSA (USA300) (53%). S. aureus colonized 40% (137/350) of index patients and 50% (405/812) of household contacts. A nares-only survey would have missed 48% of S. aureus and 51% of MRSA colonized persons. Sixty-five percent of households had >1 S. aureus genetic background identified and 26% of MRSA isolates in household contacts were discordant with the index patients' infecting MRSA strain type. Factors independently associated (P < .05) with the index strain type colonizing household contacts were recent skin infection, recent cephalexin use, and USA300 genetic background. Conclusions. In our study population, USA300 MRSA appeared more transmissible among household members compared with other S. aureus genetic backgrounds. Strain distribution was complex; >1 S. aureus genetic background was present in many households. S. aureus decolonization strategies may need to address extra-nasal colonization and the consequences of eradicating S. aureus genetic backgrounds infrequently associated with infection.

Audit of Staphylococcus aureus bacteraemia management in NHS Tayside and comparison with European Antibiotic Strategies study group international quality standards

Audit of Staphylococcus aureus bacteraemia management in NHS Tayside and comparison with European Antibiotic Strategies study group international quality standards.

Staphylococcus aureus bacteraemia (SAB) remains a significant cause of morbidity and mortality.1 National emphasis on SAB prevention has been successful in reducing the incidence, but there were still >14 000 episodes in the UK in 2007.2 The European Antibiotic Strategies (ABS) study group (http://www.abs-international.eu/index.php?id=1265) proposed SAB management indicators to investigate quality of care and tested these in five European countries.3 Our study is the first in the UK to compare current clinical practice for SAB management against the proposed ABS quality indicators, which are not yet in use in the study hospital.

Successful Veterans Affairs Initiative to Prevent Methicillin-Resistant Staphylococcus aureus Infections Revisited

Successful Veterans Affairs Initiative to Prevent Methicillin-Resistant Staphylococcus aureus Infections Revisited.

In 2011 Jain et al reported a 62% reduction of healthcare-associated methicillin-resistant Staphylococcus aureus infections that resulted from an intervention bundle. Here we present a mathematical model and prove, using parameters from the study by Jain et al, that the universal screen and isolate strategy can have contributed only marginally to the reduction in infections.

Occult Staphylococcus aureus Bacteremia in Adult Emergency Department Patients: Rare but Important

Occult Staphylococcus aureus Bacteremia in Adult Emergency Department Patients: Rare but Important.

Background. We sought to elaborate the epidemiology and outcomes of adult patients with occult Staphylococcus aureus bacteremia who were inadvertently discharged from the emergency department (ED) before positive blood culture results were obtained. Methods. Between 2001 and 2010, 759 true occult bacteremia cases were identified, including 65 patients with S. aureus bacteremia. Sixty-two patients were enrolled (case group) and analyzed using two 1:2 case-control strategies. Control group I patients were selected from among 997 S. aureus bacteremia patients directly admitted from the ED. Control group II patients were selected from 694 ED patients with occult bacteremia other than S. aureus. Cox regression analyses were used to assess the independent effect of occult S. aureus bacteremia on patient mortality. Results. There was no significant difference between the case group and control group I with respect to organ failure, septic shock, intensive care unit (ICU) admission proportion, length of ICU stay, and 30-day mortality. However, compared with control group II, the case group had significantly higher rates of hospital admission, organ failure, septic shock, ICU admission, and 30-day mortality. Age, endocarditis, and S. aureus infection were independent predictors of mortality among adult occult bacteremia patients. Conclusions. Among patients with occult bacteremia, S. aureus infections had significantly greater adverse impacts on a variety of outcome variables than other bacterial infections. Because S. aureus bacteremia is frequently associated with endovascular or deep-seated infection, it is imperative that first-line clinicians perform prudent evaluations of cases with nonapparent infection foci before discharging febrile patients from EDs.

Prevalence of infections in long-term care facilities: how to read it

Infectious Disease - Other Viral/Bacterial News Article | Prevalence of infections in long-term care facilities: how to read it |4070473.

Marchi M et al. – The prevalence of infections in LTCFs needs to be interpreted cautiously, given the effects of seasonality and case–mix variation. Repeated prevalence surveys may be a good start in individual facilities, but the identification of outbreaks requires a continuous surveillance system.