Epidemiology Of Methicillin-resistant Staphylococcus Aureus Infections Research Articles

The role of food in the spread of the Methicillin – resistant Staphylococcus aureus (MRSA)

Methicillin-resistant Staphylococcus aureus (MRSA) are important human pathogen. It is present in a wide range of animal species (pigs, cows, sheep, and chickens) even in healthy animals. Identification of MRSA in foods has led to concerns about the role of livestock in the epidemiology of MRSA infections in human. This review focuses on the spread of MRSA in different types of food and its antimicrobial resistance to the most widely used antimicrobials in human and veterinary medicine. The results of review indicates that livestock is major source of MRSA in humans and mainly transmitted to humans through contaminated food. The actual prevalence of MRSA in animals and food as well as impact to the human health is not well understood. It is clearly that MRSA is an important pathogen to veterinary medicine and human health which requires more and in-depth research to understand the hazard and take effective measures to limit it.

Methicillin-Resistant Staphylococcus Species in a cardiac surgical intensive care unit

Objective. Multi-drug resistant bacterial infections, in particular when Methicillin-Resistant Staphylococcus Aureus (MRSA) is involved, have become a relevant problem in both general and specialized intensive care units. The aim of this study was to identify the epidemiology of MRSA infections in a Cardiac Surgical Intensive Care Unit, to assess their impact on mortality and to identify predictors of MRSA infection and mortality in this population.Design and settings. A 7-year observational study in a cardiac surgery teaching center.Participants. Eight thousand, one hundred and sixty-two microbiological samples were obtained from 7,313 patients who underwent cardiac surgery in the study period.Interventions. None.Variables of interest and main results. Twenty-eight patients (0.38%) had MRSA infection. The most frequent site of MRSA isolation was from bronchoalveolar samples. Hospital mortality was 50% in patients with MRSA infection and 2% in patients without MRSA infection (p<0.001).Few preoperative independent predictors of MRSA infection and hospital mortality were found at multivariate analysis. Outcomes were found to be most influenced by perioperative variables. MRSA infection was the strongest predictor of mortality, with an odds ratio of 20.5 (95% CI 4.143-101.626).Conclusions. Methicillin-resistant Staphylococcus aureus infections following cardiac surgery still have a strong impact on the patients’ outcome. More efforts should be directed toward the development of new risk analysis models that might implement health care practices and might become precious instruments for infection prevention and control.

Methicillin-Resistant Staphylococcus aureus and the Eye: Current Concepts and Management Strategies

Methicillin-resistant Staphylococcus aureus (MRSA) remains one of the most important causes of nosocomial infections worldwide. This review explores the history and epidemiology of MRSA infections with a detailed analysis of its molecular subtyping, target populations, virulence factors, and modes of transmission. In addition, it specifically discusses the spectrum of eye diseases caused by MRSA, reviews the current ophthalmic literature, addresses the controversy regarding ophthalmic antibiotic resistance to MRSA, and examines alternative treatment strategies.

Does the Nose Know? An Update on MRSA Decolonization Strategies

Colonization with methicillin-resistant Staphylococcus aureus (MRSA) is an important step in the pathogenesis of active infection and is a key factor in the epidemiology of MRSA infection. Decolonization of patients found to have MRSA carriage may be of value in certain patient populations, especially those undergoing elective surgery. However, the most commonly used agent for decolonization, mupirocin, comes with a considerable risk of resistance if widely employed. Recent studies of other novel agents for decolonization show promise, but further research is necessary. This review focuses on the pathogenesis from MRSA colonization to infection, identifies the risk factors for colonization, and summarizes decolonization strategies, including novel approaches that may have a role in decreasing MRSA disease burden.

Changing epidemiology of methicillin-resistant Staphylococcus aureus in the Veterans Affairs Healthcare System, 2002–2009

The epidemiology of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) is changing. Temporal trends and differences between healthcare settings must be described in order to better predict future risk factors associated with this dangerous bacterial infection. A national MRSA-infected cohort was identified from 2002 to 2009 in the Veterans Affairs Healthcare System of the United States: hospital (HOS), long-term care (LTC), and outpatient (OPT). We analyzed within-setting time trends using generalized linear mixed models and between-setting differences with χ(2) and Wilcoxon rank-sum tests. The incidence of S. aureus, methicillin-susceptible S. aureus (MSSA), and MRSA infections increased significantly over time in all three settings based on modeled annual percentage changes (P < 0.001). MRSA incidence rates rose by 14, 10, and 37% per year in the HOS, LTC, and OPT settings, respectively. Among 56,345 MRSA-infected patients, the comorbidity burden was highest among LTC inpatients (n = 4,427) and lowest among outpatients (n = 7,250), with an average absolute difference in specific comorbidities of +2 and -7%, respectively, compared to HOS inpatients (n = 44,668). Over time, there was a significant (P ≤ 0.02) decrease in previous inpatient admissions and surgeries (all settings); diabetes with complications and surgical site infections (HOS, OPT); and median length of stay and inpatient mortality (HOS, LTC). Alternatively, obesity, chronic renal disease, and depression were more common between 2002 and 2009 (P ≤ 0.02). Over the past 8 years, we observed significant changes in the epidemiology of MRSA infections, including decreases in traditional MRSA risk factors, improvements in clinical outcomes, and increases in other patient characteristics that may affect risk.

Methicillin-Resistant Staphylococcus aureus in Animals

Methicillin-resistant Staphylococcus aureus (MRSA) is a critically important human pathogen that is also an emerging concern in veterinary medicine and animal agriculture. It is present in a wide range of animal species, including dogs, cats, rabbits, horses, cattle, pigs, poultry, and exotic species, both as a cause of infection and in healthy carriers. Identification of MRSA in various species and in food has led to concerns about the roles of animals, both pets and livestock, in the epidemiology of MRSA infection and colonization in humans. There is evidence of the role of food animals in human MRSA infections in some countries and of pets as a possible source of human infection. Some groups of individuals who work closely with animals, such as veterinarians, have high MRSA colonization rates. This article includes discussions of MRSA in human medicine, animals, and food, as well as its interspecies transmission, colonization, infection, strains, and affected populations. However, clear answers are lacking in many of these areas and limited studies may lead to premature conclusions. It is certain that animals are a source of human MRSA infection in some circumstances--but humans may also serve as sources of infection in animals. Changes in the epidemiology of MRSA in one species may be reflected in changes in other species. The true scope of MRSA in animals and its impact on human health are still only superficially understood, but it is clear that MRSA is a potentially important veterinary and public health concern that requires a great deal more study to enhance understanding and effective response.

Methicillin-resistant Staphylococcus aureus Infection After Lung Transplantation: 5-year Review of Clinical and Molecular Epidemiology

Data on the epidemiology of MRSA infection in lung transplantation is limited. We performed a 5-year retrospective study to assess the incidence and microbiologic and clinical characteristics of methicillin-resistant Staphylococcus aureus (MRSA) infection in a cohort of 163 lung transplant recipients. Seventeen patients with MRSA colonization and/or infection were identified, for a calculated incidence rate of 76.1 cases per 1,000 transplanted-years. Pulsed-field gel electrophoresis identified 3 different distinct MRSA profiles, all of them consistent with hospital-associated MRSA infection. Despite negative polymerase chain reaction (PCR) for the virulence factor Panton-Valentine leukocidin, MRSA infections resulted in significant disease and morbidity.

Panton–Valentine leukocidin‐positive methicillin‐resistant Staphylococcus aureus infections in children with cancer

New strains of methicillin-resistant Staphylococcus aureus (MRSA) which frequently carry the Panton-Valentine leukocidin (PVL) genes have been recognized to cause invasive infections in otherwise healthy children and adults. However, the epidemiology of PVL-positive MRSA infections has not been described in children or adults with cancer. The epidemiology of MRSA infections in patients with cancer was retrospectively studied from 2000 to 2007. Molecular typing was performed by polymerase chain reaction (PCR) for the detection of the PVL genes. Staphylococcus cassette chromosome (SCC) mec and spa typing was performed on all PVL-positive isolates. A total of 88 MRSA isolates from clinically distinct infectious episodes were collected from 88 patients with cancer during the 8-year study period. Infections were predominant in the skin and soft tissues (SSTI; P = 0.0003). PVL-positive isolates, bearing the type IV SCCmec element, encoding the gene for methicillin resistance, increased significantly during this period (P = 0.043) and comprised 35 of 88 (40%) MRSA isolates. Of these 35 isolates, 32 belonged to spa type 8 and were USA300 genotype. Patients infected with PVL-positive strains did not have more SSTI (P = 0.166) or bacteremia (P = 0.510) as compared to patients with PVL-negative strains. A greater percentage of PVL-positive isolates were susceptible to ciprofloxacin (P = 0.006). PVL-positive MRSA infections are not associated with a higher morbidity as compared to PVL-negative MRSA infections in children with cancer.

Reemergence of epidemic methicillin-resistant Staphylococcus aureus in a general hospital associated with changing Staphylococcal strains

An epidemic of methicillin-resistant Staphylococcus aureus (MRSA) infections involving 323 patients occurred at the University of Cincinnati Hospital from 1977 to 1981. Subsequently, endemic MRSA persisted in the hospital for 6 years, until 1987, when a new epidemic began with 223 patients becoming infected over 3 years. Between the two epidemics, there was a major change in the MRSA recovered from infected patients, as demonstrated by three epidemiologic markers. Antibiograms showed that the tetracycline-resistant MRSA involved in the first epidemic was replaced by tetracycline-susceptible MRSA in the second epidemic; bacteriophage typing indicated that the original epidemic strain, D11/83A/85, had been replaced by new strains, many of which were susceptible to phage 54; and restriction endonuclease analysis of plasmid DNA confirmed that a single strain was involved in the first epidemic and that multiple strains were present in the second epidemic. The epidemiology of MRSA infections in the hospital changed with the change in staphylococcal strains. The first epidemic was hospital based with most infections occurring in surgical patients, and the burn unit was the major reservoir. In contrast, 28% of the patients in the second epidemic had community-acquired infections, and nursing home patients were an important source of these infections. Also, 29% of the hospital-acquired infections in this epidemic occurred in nonsurgical patients. This time the burn unit was not a reservoir of infection, but other intensive care units were. The increased diversity of strains of MRSA in the second epidemic might be related to increased transmission in the community and more widespread transmission in the hospital.