MRSA

Methicillin-resistant Staphylococcus aureus (MRSA) is a multi-drug resistant pathogen, which is responsible for increasing cases of serious diseases, including life-threatening diseases and nosocomial and community-acquired infections. Laboratory identification of MRSA is crucial and essential both for initiation of appropriate antimicrobial therapies and for effective infection control strategies that are designed to limit the spread of MRSA. In spite of the availability of commercial kits for MRSA detection in the market, the Clinical and Laboratory Standards Institute (CLSI) recommends the use of phenotypic methods, such as the disk diffusion method with oxacillin or with cefoxitin, as well as a serial dilution method with oxacillin. Nevertheless, some studies have shown that results obtained with such phenotypic methods are controversial. The aim of the study described in this paper was to comparatively evaluate the traditional susceptibility testing for MRSA with PCR as the gold standard assay. Analysis of collection (n = 68) isolates of Staphylococcus aureus revealed that the serial dilution method with oxacillin possessed the highest sensitivity (at 100%). In contrast, the disk diffusion methods with oxacillin and cefoxitin showed lower sensitivity
(95.83%, 95% CI (78.81% - 99.30%)). Furthermore, the borderline value of zone inhibition diameters for cefoxitin might be considered as a risk, and they may give false-susceptible result.

Background
Methicillin-resistant Staphylococcus aureus (MRSA) is a devastating pathogen that is associated with high morbidity and mortality worldwide. Livestock are a well-known reservoir for this pathogen, which poses substantial health risks for livestock workers. Little is known about the epidemiology of livestock-associated MRSA (LA-MRSA) among livestock workers in Eastern Europe.

Methods
To study the epidemiology of LA-MRSA among swine workers in Romania, we collected and characterized nasal and oropharygneal samples from swine workers on commercial pig farms. A survey that included questions about work-related tasks, biosafety practices, contact with animals, and health status was used to assess the risk factors that were potentially associated with LA-MRSA colonization.

Results
The prevalence of MRSA colonization among swine workers was 6.8%. Two LA-MRSA strains with the spa types t034 and t011 and one likely community-associated MRSA strain with the spa type t321 were isolated from workers on five farms. Interestingly, all MRSA carriers worked on farms that imported animals from other production facilities.

Conclusion
This is the first study to confirm the presence of LA-MRSA among swine workers in Romania and suggests the need to minimize the risk of LA-MRSA-related infections in swine workers and their community contacts. The findings also suggest a link between the commercial movement of swine and the introduction of LA-MRSA.

Background The correct management of immunocompromised patients with pneumonia is debated. We evaluated the prevalence, risk factors, and characteristics of immunocompromised patients coming from the community with pneumonia. Methods We conducted a secondary analysis of an international, multicenter study enrolling adult patients coming from the community with pneumonia and hospitalized in 222 hospitals in 54 countries worldwide. Risk factors for immunocompromise included AIDS, aplastic anemia, asplenia, hematological cancer, chemotherapy, neutropenia, biological drug use, lung transplantation, chronic steroid use, and solid tumor. Results At least 1 risk factor for immunocompromise was recorded in 18% of the 3702 patients enrolled. The prevalences of risk factors significantly differed across continents and countries, with chronic steroid use (45%), hematological cancer (25%), and chemotherapy (22%) the most common. Among immunocompromised patients, community-acquired pneumonia (CA...

Optimal early vancomycin target exposure remains controversial. To clarify the therapeutic exposure range, we investigated the association between vancomycin exposure and treatment outcomes or nephrotoxicity in patients with methicillin-resistant Staphylococcus aureus (MRSA) infection. This retrospective study reviewed clinical data obtained from 131 patients with MRSA infections between January 2017 and September 2019. Clinical outcomes included treatment failure, 30-day mortality, microbiological failure, and acute kidney injury. We measured serum vancomycin levels after the first dose to 48 h and estimated vancomycin exposure using the Bayesian theorem. The minimum inhibitory concentration (MIC) of antimicrobial agents was determined using the broth microdilution method. Classification and Regression Tree analyses identified day 1 and 2 exposure thresholds associated with an increased risk of failure and nephrotoxicity. Treatment failure (27.9% vs. 33.3%) and 30-day mortality (26...

To study the Antibiotic resistance determination of S. aureus isolates and screening for MRSA. This was in-vitro study on MRSA isolates received from clinical samples in the department of microbiology during three months (January 2015-March 2015). Staphylococci were identified by catalase, coagulase and DNAse tests. The samples were cultured on blood agar and MacConkey's agar plates. Antibiotic susceptibility tests were carried out by disc diffusion method. The disc used was Amikacin (30μg), Doxycycline (30μg), Co-trim0oxazole (25μg), Gentamicin (10μg), Penicilin (10μg), Erythromycin (15μg), Clindamycin (2μg), Vancomycin (30μg), Linezolid (30μg), Cefoxitin (30μg), Fusidic acid (10 g), Chloramphenicol (30μg) and Ciprofloxacin (5μg). Our results indicate that out of 112 positive isolates of S. aureus, 34 (30.35%) were found to be MRSA. These isolates were also resistant to different commonly prescribed other anti-staphylococcal antibiotics. A total of 34 (30.35%) MRSA was isolated...

Aim: The research was to investigate the antibiotic resistance profile and to screen for methicillin-resistant Staphylococcus aureus (MRSA) from nasal mucosa swab of dogs. Materials and Methods: The samples were collected from three pet clinics, three K9 units, one veterinary teaching hospital, and one kennel in Surabaya. Of the 50 total samples, 24 confirmed S. aureus strains, which were used for antibiotic sensitivity tests using a disk diffusion method and screening of MRSA used oxacillin resistance screening for base (ORSAB). Results: This study showed that there were differences in antibiotic resistance patterns among different locations. Fourteen isolates were screened for MRSA by culture on ORSAB. Conclusion: MRSA carriage was found on nasal swab of dogs, and dogs can act as reservoir of MRSA for spreading to human health. Keywords: antibiotic-resistant, dogs, methicillin-resistant Staphylococcus aureus, Staphylococcus aureus.

Aim: This study aimed to investigate the antibacterial efficacy of eight commercially available essential oil (EO) blends and characterize the effect on the expression of some virulence genes against methicillin-resistant Staphylococcus aureus (MRSA). Materials and Methods: In vitro evaluation of the antimicrobial effects of oils against MRSA was performed using the disk diffusion method and by measuring the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The EOs (A-F) were contained (β-pinene, carvacrol, carvone, dimethyl trisulfide, linalool, limonene, menthol, monoterpene hydrocarbons, and thymol) in different amounts. In addition, a real-time polymerase chain reaction was also used to determine the gene expression of the virulence genes (intercellular adhesion cluster [ica]-9, ica-15, and RNA III) against MRSA (ATCC 43300) after treatment with selected oils. Results: Among the eight EOs evaluated, EO (D), (E), and (A) showed, in general, ...

Background and Aim: Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most recognized "superbugs" and a common cause of community-associated and nosocomial infections; furthermore, when chicken meat is considered a good growth medium for S. aureus to make a plausible vehicle to propagate MRSA, then this study was conducted to evaluate the efficiency of ozonated water (0.5 ppm) in the elimination or reduction of MRSA contaminating fresh and frozen chicken meat sold in local markets in the Wasit Province. Materials and Methods: A total of 72 samples of fresh and frozen chicken meat were randomly collected from dissimilar native markets: Fresh chicken meat (n=32) and frozen chicken meat (n=40). Isolation and identification of MRSA isolates were conducted using standard bacteriological, biochemical, RapID™ Staph Plus System (Remel, R8311009), and latex agglutination tests such as Dry SPOT Staphytect Plus (Oxoid, DR0100M) and PBP2' Test Kit (Oxoid, DR0900A). ...

The prevalence of diverse MRSA (methicillin-resistant Staphylococcus aureus) types in both hospital and community settings is a major health problem worldwide. Here we compare hospital-acquired MRSAs with large type II SCCmec elements with those prevalent in both hospital and community settings with smaller type IV SCCmec elements. We find that the type II but not the type IV SCCmec element causes the bacteria to reduce their levels of costly toxin expression. We compare the relative growth rates of these MRSA types and show that the type II SCCmec carrying MRSAs are more affected than those carrying type IV elements and from this we hypothesize that offsetting the costs associated with antibiotic resistance and toxin expression is why the type II are confined to hospital environments where antibiotic use, the prevalence of immunocompromised individuals and vector-mediated transmission is high. In contrast, those MRSAs that are also successful in the community can maintain their hig...

Surgical Site Infections (SSIs) are an unfortunate and sometimes disastrous complication associated with spine surgery. More than 50% of SSIs in orthopaedic surgery are caused by Staphylococcus aureus and 85% of S. aureus SSIs are caused by bacterial strains found in the patient's nares.1 Infections with methicillin-resistant Stahylococcus aureus (MRSA) is one of the most problematic SSIs and frequently leads to morbidity, mortality and increased costs of surgical care.234 Hospital-Acquired Conditions (HAC), or conditions deemed by CMS as reasonably preventable, have been targeted as an area of pay for performance. On July 31, 2008, in the Inpatient Prospective Payment System (IPPS) Fiscal Year (FY) 2009 Final Rule, CMS included SSIs for the HAC payment provision. To encourage hospitals to avoid hospital-acquired conditions, as of October 1, 2008, Medicare no longer pays hospitals for their higher costs of care that result when a patient is harmed by SSI if it was hospital-acquired. Medicare prohibits the hospital from billing the beneficiary for the difference between the lower and higher payment rates.5 One strategy that can be used is to screen patient's pre-operatively for the presence of MRSA and to decolonize the patients that are carriers and also adjust the perioperative antibiotic regimen of known carriers. Although this may not total eliminate the risk of a SSI, it will diminish the risk of an SSI.6 There is also some evidence of MRSA colonization preoperatively is indicative of the state of the host and thus so indicates that SSIs in general are more likely in this type of patient.7 Screening for MRSA is strategy that has worked effectively for us and has been validated in the literature for both adults and children and involves topical mupiricin as well as antibiotics.8 Some studies have validated mupiricin topically by itself but we did not seem to have the same anecdotal success.910 This protocol is also suggested by the North American Spine Society Safety Committee.11 The NASS Patient Safety Committee recognized that pre-operative MRSA screening and treatment may likely only result in the short term eradication of MRSA, but this may be sufficient enough to prevent early SSI.12 1 AAOS Patient Safety Committee, The Current State of Bacterial Screening and Decolonization in Orthopaedic Surgery. Screen patient 10-14 days prior to surgery If negative: chlorhexidine wipe/wash protocol for all these patients (at least 3 days of wipe/wash to surgical site) and then cefazolin as the pre-op antibiotic If positive: treat with bactroban to nares and chlorhexidine wash/wipes to the surgical site for 5 days and consider rescreening pre-operatively • Rescreen with negative result available prior to operation: consider prophylactic administration of cephalosporin and final chlorhexidine wife immediately pre-operatively • Rescreen with positive result available prior to operation: Retreat with bactroban and consult with Infection Control Department • If not rescreening prior to operation or after treatment or if rescreening results are only available after operation, consider treating with vancomycin At the surgeon's discretion, vancomycin may be considered in patients with a history of MRSA infection

Innovative approaches to the use of existing antibiotics is an important strategy in efforts to address the escalating antimicrobial resistance crisis. We report a new approach to the treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections by demonstrating that oxacillin can be used to significantly attenuate the virulence of MRSA despite the pathogen being resistant to this drug. Using mechanistic in vitro assays and in vivo models of invasive pneumonia and sepsis, we show that oxacillin-treated MRSA strains are significantly attenuated in virulence. This effect is based primarily on the oxacillin-dependent repression of the accessory gene regulator quorum-sensing system and altered cell wall architecture, which in turn lead to increased susceptibility to host killing of MRSA. Our data indicate that β-lactam antibiotics should be included in the treatment regimen as an adjunct antivirulence therapy for patients with MRSA infections. This would represent an important change to current clinical practice for treatment of MRSA infection, with the potential to significantly improve patient outcomes in a safe, cost-effective manner.

Antibiotics are chemotherapeutic agents used for treating several illnesses caused by fungi, bacteria and parasites. These play a great role in inhibiting or suppressing the growth of the said microorganisms. Most of the antibiotics are derived from fungi or bacteria, but nowadays they are now chemically modified from natural substances which are considered semi – synthetic. Through time, there are more than 200 antibiotics produced for specific illnesses but only at least 150 of them are effectively used for treatment (Zuchora-Walske 2014). They have also showed promising results in eliminating diseases like gonorrhea, tuberculosis, Methicillin resistant Stapyhlococcus aureus (MRSA), and other common infections. These, in hand, pose drug dependence among people. But bacterial pathogens, alongside several environmental and health conditions consider these therapeutic agents a threat which comes to us as when these microorganisms become resistant to almost all the commercially available antibiotics. This is considered a big challenge to us, specifically the field of research. What do we do to solve this problem? What other substances could be used to fight off these new pathogenic strains? Multi drug resistant strains evolve in the presence of climacteric instability, war and migrations due to the accelerated use and misuse of antibiotics, as well as poor infection prevention and control. The extensive use and dependence on such has led to the development of strains which remain unrecognized to the research community.

Staphylococcus aureus (S. aureus) causes the vast majority of skin and soft tissue infections (SSTIs) in humans. S. aureus has become increasingly resistant to antibiotics and there is an urgent need for new strategies to tackle S. aureus infections. Vaccines offer a potential solution to this epidemic of antimicrobial resistance. However, the development of next generation efficacious anti-S. aureus vaccines necessitates a greater understanding of the protective immune response against S. aureus infection. In particular, it will be important to ascertain if distinct immune mechanisms are required to confer protection at distinct anatomical sites. Recent discoveries have highlighted that interleukin-17-producing T cells play a particularly important role in the immune response to S. aureus skin infection and suggest that vaccine strategies to specifically target these types of T cells may be beneficial in the treatment of S. aureus SSTIs. S. aureus expresses a large number of cell wall-anchored (CWA) proteins, which are covalently attached to the cell wall peptidoglycan. The virulence potential of many CWA proteins has been demonstrated in infection models; however, there is a paucity of information regarding their roles during SSTIs. In this review, we highlight potential candidate antigens for vaccines targeted at protection against SSTIs.

The most recent epidemic of Ebola virus disease (EVD), beginning in Guinea in December 2013 and still underway as of September 2015, has claimed almost 11 300 lives and resulted in almost 28 000 cases. The first EVD epidemic in history to span multiple countries at once; the outbreak caught the world unprepared, undoubtedly leading to higher illness and death counts that may have occurred in areas with solid medical infrastructure. An analysis of the many facets of the epidemic touches on many important topics covered in an introductory global health course, including issues of economics, ethics, culture, infectious disease, policy, preparedness and technology. However, in contrast to many global health offerings, a study of Ebola provides a unifying narrative throughout the course.

Background. Previous studies indicated that vancomycin is inferior to beta-lactams for treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections. However, it is unclear if this association is true for both empiric and definitive therapy. This study compared beta-lactams with vancomycin for empiric and definitive therapy of MSSA bloodstream infections among patients admitted to 122 hospitals.

Methods. This retrospective cohort study included all patients admitted to Veteran's Affairs hospitals from 2003 to 2010 who had positive blood cultures for MSSA. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards regression. Empiric therapy was defined as starting treatment 2 days before until 4 days after the first MSSA blood culture was collected. Definitive therapy was defined as starting treatment between 4 to 14 days after the first positive blood culture was collected.

Results. Patients who received empiric therapy with a beta-lactam had similar mortality compared with vancomycin (HR: 1.03; 95% CI: 0.89-1.20) after adjusting for other factors. However, patients who received definitive therapy with a beta-lactam had 35% lower mortality compared with patients receiving vancomycin (HR: 0.65; CI: 0.52-0.80) after controlling for other factors. The hazard of mortality decreased further for patients who received cefazolin or an antistaphylococcal penicillin compared with vancomycin (HR: 0.57; CI: 0.46-0.71).

Conclusions. For patients with MSSA bloodstream infections, beta-lactams are superior to vancomycin for definitive therapy but not for empiric treatment. Patients should receive a beta-lactam for definitive therapy, specifically an antistaphylococcal penicillin or cefazolin.

Background. Livestock-associated Staphylococcus aureus (LA-SA) has been documented worldwide. However, much remains unknown about LA-SA colonization and infection, especially in rural environments.

Methods. We conducted a large-scale prospective study of 1342 Iowans, including individuals with livestock contact and a community-based comparison group. Nasal and throat swabs were collected to determine colonization at enrollment, and skin infection swabs over 17 months were assessed for S. aureus. Outcomes included carriage of S. aureus, methicillin-resistant S. aureus (MRSA), tetracycline-resistant S. aureus (TRSA), multidrug-resistant S. aureus (MDRSA), and LA-SA.

Results. Of 1342 participants, 351 (26.2%; 95% confidence interval [CI], 23.8%–28.6%) carried S. aureus. MRSA was isolated from 34 (2.5%; 95% CI, 1.8%–3.5%) and LA-SA from 131 (9.8%; 95% CI, 8.3%–11.5%) of the 1342 participants. Individuals with current swine exposure were significantly more likely to carry S. aureus (prevalence ratio [PR], 1.8; 95% CI, 1.4–2.2), TRSA (PR, 8.4; 95% CI, 5.6–12.6), MDRSA (PR, 6.1; 95% CI, 3.8–10.0), and LA-SA (PR, 5.8; 95% CI, 3.9–8.4) than those lacking exposure. Skin infections (n = 103) were reported from 67 individuals, yielding an incidence rate of 6.6 (95% CI, 4.9–8.9) per 1000 person-months.

Conclusions. Current swine workers are 6 times more likely to carry MDRSA than those without current swine exposure. We observed active infections caused by LA-SA. This finding suggests that individuals with livestock contact may have a high prevalence of exposure to, and potentially infection with, antibiotic-resistant S. aureus strains, including LA-SA strains.

The present study was undertaken for the purpose of defining the epidemiology and genetic relatedness of Staphylococcus aureus strains in a region of Italy by investigating the molecular background for which resistance to methicillin, mediated by the acquisition of another penicillin-binding protein gene, is embedded. Restriction fragment length polymorphism (RFLP) data were used for phylogenetic analyses, since genetic distance values can be used as a general measure of the number of events generating distinct clones. The percentages of methicillin-resistant S. aureus (MRSA) isolates in a six-month period from inpatients and outpatients were, respectively, 12% (22 out of 180) and 0.4% (1 out of 257). On the basis of RFLP obtained after pulsed field gel electrophoresis (PFGE), it was possible to designate isolates as indistinguishable, closely related, possibly related and unrelated. We were able to demonstrate the occurrence of at least five distinct MRSA cross-infection episodes in two hospitals, four involving two patients each and one involving four patients. Phylogenetic analyses overcame the simple pairwise comparison of common bands between strains, and provided a comprehensive epidemiological scenario, identifying three major clusters of MRSA, including different levels of genetic relatedness, while excluding the circulation of a single clone in Italy. Moreover, multidimensional scaling analysis of the obtained genetic distance confirmed that MRSA strains belong to a restricted set of clones, thus demonstrating the relatedness of broad evolutionary lineages within the species S. aureus.

The prevalence of diverse MRSA (methicillin-resistant Staphylococcus aureus) types in both hospital and community settings is a major health problem worldwide. Here we compare hospital-acquired MRSAs with large type II SCCmec elements with those prevalent in both hospital and community settings with smaller type IV SCCmec elements. We find that the type II but not the type IV SCCmec element causes the bacteria to reduce their levels of costly toxin expression. We compare the relative growth rates of these MRSA types and show that the type II SCCmec carrying MRSAs are more affected than those carrying type IV elements and from this we hypothesize that offsetting the costs associated with antibiotic resistance and toxin expression is why the type II are confined to hospital environments where antibiotic use, the prevalence of immunocompromised individuals and vector-mediated transmission is high. In contrast, those MRSAs that are also successful in the community can maintain their high levels of toxin expression due to a lower fitness burden associated with the smaller SCCmec element.

Methicillin-resistant Staphylococcus aureus (MRSA) is a growing infectious concern, mainly in the context of its rapid adaptation to novel antibiotic options for its treatment and the growing morbidity, mortality, and healthcare costs associated with its emergence. the authors sought to investigate whether an older antibiotic, such as trimethoprim-sulfamethoxazole (SXT), may have a role in treating MRSA-related infections, according to the available literature on the subject. The authors reviewed literature data on: resistance of MRSA to SXT worldwide in recent years, efficacy of SXT for MRSA decolonization or prophylaxis from MRSA infections, and clinical therapeutic efficacy of SXT in treating mild or severe community-acquired or hospital-acquired MRSA infections. Resistance varies worldwide, in general being low in the industrialized world and higher in developing countries. SXT is one of the numerous understudied options for MRSA decolonization and is growingly recognized as potentially effective in preventing MRSA infections in certain settings. Limited data on its therapeutic efficacy are encouraging, at least for mild, community-acquired infections. SXT may represent a cost-effective alternative weapon against MRSA. Its utility against this increasingly threatening pathogen need clarification through further clinical trials.

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) has become a leading cause of infectious disease morbidity and mortality in the United States. The epidemiology of the organism has changed, with novel strains emerging in the community among individuals lacking any healthcare contact. Although direct human-to-human transmission via skin contact is one way for this organism to spread, transmission via environmental contamination of fomites or through air are other potential ways that the organism can be acquired. As such, an improved understanding of MRSA transmission is needed to implement maximally effective control and prevention interventions. We review the research documenting the role of the environment in MRSA spread.

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) has changed dramatically over the past 15 years. Initially a nosocomial pathogen, newly emergent strains of MRSA have become increasingly common in the community among individuals lacking contact with healthcare. More recently, a third group of MRSA strains have been identified in association with livestock, particularly swine. These strains, termed livestock-associated MRSA, have now been identified in Europe, North America, and Asia in humans and animals. One molecular type, ST398, has been the dominant strain of livestock-associated MRSA identified to date. The emergence of this strain in animals and humans will be described in this review, including colonization and clinical infections caused by this strain. We also discuss lingering research questions and implications for controlling spread of this bacterium in an agricultural environment and beyond.

An estimated 95,000 people developed methicillin-resistant Staphylococcus aureus (MRSA) infections during 2005 of which 14% were community-associated and 85% were hospital or other health setting associated, and 19,000 Americans died from these infections that year.

Purpose: To explore health care providers’ perspectives on management of skin and soft tissue infections to gain a better understanding of the problems faced by busy providers in primary care settings.

Methods: Focus group meetings were held at 9 family physician offices in the Iowa Research Network. Seventy-eight clinicians including physicians, nurses, nurse practitioners, and house officers attended. Meeting audiotapes were transcribed and coded by 3 investigators, and a MRSA-management taxonomy was developed.

Findings: The main themes that emerged from the focus groups included epidemiology, diagnosis, treatment, management, prevention, special populations, and public relations. The incidence of MRSA infections was perceived to have increased over the past decade. However, diagnosis and treatment protocols for physicians in the outpatient setting have lagged behind, and no well-accepted diagnostic or treatment algorithms were used by physicians attending the focus groups.

Conclusion: The clinicians in this study noted considerable confusion and inconsistency in the management of skin and soft tissue infections, particularly those due to MRSA.

We report a novel vga(A) detected in 3 methicillin-resistant Staphylococcus aureus ST398 recovered from swine and a swine caretaker in the United States. Strains were wild type for L3 and L4, but positive for vga(A) and tet(M). vga(A) was plasmid-located (ca. 24-kb) and demonstrated mobilization genes upstream and a transposase belonging to the IS3 family located downstream.