scholarly journals Investigation of Various Virulence Factors and SCCmec Types in the Healthcare-associated and Community-associated Methicillin Resistance Staphylococcus aureus Strains

2020 ◽  
Vol 26 (2) ◽  
pp. 113-118
Author(s):  
Sureyya Gul Yurtsever ◽  
◽  
Abdurrahman Aygul ◽  
Ismail Ozturk ◽  
Salih Atakan Nemli ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Methicillin Resistance ◽  
Healthcare Associated ◽  
Sccmec Types

scholarly journals GENETIC MECHANISMS OF METHICILLIN RESISTANCE IN STAPHYLOCOCCUS AUREUS (MRSA) AND ITS CAPACITY OF TRANSMISSION: A BRIEF REVIEW

2017 ◽  
Vol 9 (2) ◽  
pp. 29-37
Author(s):  
Maja Velhner ◽  
Gordana Kozoderović ◽  
Ljiljana Suvajdžić ◽  
Dalibor Todorović ◽  
Jelena Petrović
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Factors ◽  
Methicillin Resistance ◽  
Genetic Regulation ◽  
Human Pathogens ◽  
Spa Typing ◽  
Healthy Human ◽  
Pathogenic Potential ◽  
Mrsa Strains ◽  
Healthcare Associated

Methicillin-resistant Staphylococcus aureus is one of the most important human pathogens. Th ese bacteria have the ability to colonize animals andcross species barriers. Th ree major groups of MRSA strains have emerged. Healthcare associated MRSA and community acquired MRSA strains have potential to spread worldwide and oft en persist in hospitals and communities as clonal strains. Th e livestock-associated MRSA has been isolated from healthy human carriers but also from infected patients all around the world. Molecular typing of staphylococcal cassette chromosome mec (SCCmec), multilocus sequence typing in combination with pulse fi eld gel electrophoresis and spa typing are most frequently used for genetic characterization of MRSA strains. Th e community-acquired MRSA strains are capable of producing Panton Valentine leukocidin (PVL) cytotoxin which is their major virulence determinant. MRSA strains possess a number of virulence factors that are common in other bacteria and it is still not entirely explained which virulence factors or mechanisms of their regulation are important for the pathogenic potential, persistence in the environment or the ability to cause detrimental infection in patients. Recently, as a contribution to the progress of molecular biology, peculiar mechanisms of genetic regulation of virulence genes have been discovered and their role in pathogenesis of infection and epidemiology of MRSA has been studied.

scholarly journals Derivation and validation of clinical prediction rules for reduced vancomycin susceptibility in Staphylococcus aureus bacteraemia

2012 ◽  
Vol 141 (1) ◽  
pp. 165-173 ◽  
Author(s):  
J. H. HAN ◽  
W. B. BILKER ◽  
P. H. EDELSTEIN ◽  
K. B. MASCITTI ◽  
E. LAUTENBACH
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Prediction Rule ◽  
Clinical Prediction Rule ◽  
Clinical Prediction ◽  
Broth Microdilution ◽  
Healthcare Associated Infection ◽  
Final Model ◽  
Individualized Management ◽  
Healthcare Associated

SUMMARYReduced vancomycin susceptibility (RVS) may lead to poor clinical outcomes in Staphylococcus aureus bacteraemia. We conducted a cohort study of 392 patients with S. aureus bacteraemia within a university health system. The association between RVS, as defined by both Etest [vancomycin minimum inhibitory concentration (MIC) >1·0 μg/ml] and broth microdilution (vancomycin MIC ⩾1·0 μg/ml), and patient and clinical variables were evaluated to create separate predictive models for RVS. In total, 134 (34·2%) and 73 (18·6%) patients had S. aureus isolates with RVS by Etest and broth microdilution, respectively. The final model for RVS by Etest included methicillin resistance [odds ratio (OR) 1·51, 95% confidence interval (CI) 0·97–2·34], non-white race (OR 0·67, 95% CI 0·42–1·07), healthcare-associated infection (OR 0·56, 95% CI 0·32–0·96), and receipt of any antimicrobial therapy ⩽30 days prior to the culture date (OR 3·06, 95% CI 1·72–5·44). The final model for RVS by broth microdilution included methicillin resistance (OR 2·45, 95% CI 1·42–4·24), admission through the emergency department (OR 0·54, 95% CI 0·32–0·92), presence of an intravascular device (OR 2·24, 95% CI 1·30–3·86), and malignancy (OR 0·51, 95% CI 0·26–1·00). The availability of an easy and rapid clinical prediction rule for early identification of RVS can be used to help guide the timely and individualized management of these serious infections.

scholarly journals Isolation, Detection and Molecular Characterization of Staphylococcus aureus from Postoperative Infections

2020 ◽  
pp. 63-67
Author(s):  
Ritya Mary Jibu ◽  
R. V. Geetha ◽  
T. Lakshmi
Keyword(s):  
Staphylococcus Aureus ◽  
Wound Infection ◽  
Molecular Characterization ◽  
Methicillin Resistance ◽  
Healthcare Associated Infection ◽  
Postoperative Infections ◽  
Coagulase Negative Staphylococci ◽  
Mrsa Strains ◽  
Healthcare Associated

Post operative infections that occur after surgical procedures can cause a lot of complications like sepsis, organ failure or even death. These are the third most commonly reported healthcare associated infection. The most common cause of wound infection regardless of procedure performed remains gram-positive cocci which comprise more than 50% of all infections. Specifically, Staphylococcus aureus and coagulase-negative staphylococci are the most frequent organisms isolated from a wound infection. There has been an increasing incidence of MRSA strains reported in hospitals across the globe. The main aim of our study is isolation, detection and molecular characterization of Staphylococcus aureus from postoperative infections.  Samples were collected from post operative patients with infected wounds. The area around the wound was cleaned. Exudates were collected from the wound with a sterile swab stick. The samples were inoculated on different solid culture mediums and the plates were incubated in the presence of oxygen at 37°C overnight. There were many standard procedures done in which tube coagulase was taken as the main criteria. Antibiotic susceptibility testing was done by Kirby Bauer method following Clinical and Laboratory Standards Institute (CLSI) guidelines using commercially available cefoxitin (30 μg) disc (HiMedia) and the results were compared with Staphylococcus aureus ATCC 25923 and MRSA ATCC 43300 control strains. The MRSA strains were identified and detection of Mec A gene that codes for methicillin resistance is done using PCR technique.

Healthcare-AssociatedStaphylococcus aureusBacteremia and the Risk for Methicillin Resistance: Is the Centers for Disease Control and Prevention Definition for Community-Acquired Bacteremia Still Appropriate?

2005 ◽  
Vol 26 (2) ◽  
pp. 204-209 ◽  
Author(s):  
Olivier Lesens ◽  
Yves Hansmann ◽  
Eimar Brannigan ◽  
Susan Hopkins ◽  
Pierre Meyer ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Disease Control ◽  
Methicillin Resistance ◽  
Blood Cultures ◽  
New Classification ◽  
Control And Prevention ◽  
Centers For Disease Control ◽  
Mrsa Strains ◽  
Healthcare Associated ◽  
Hospital Acquired

AbstractObjective:To evaluate a new classification for bloodstream infections that differentiates hospital acquired, healthcare associated, and community acquired in patients with blood cultures positive forStaphylococcus aureus.Design:Prospective, observational study.Setting:Three tertiary-care, university-affiliated hospitals in Dublin, Ireland, and Strasbourg, France.Patients:Two hundred thirty consecutive patients older than 18 years with blood cultures positive forS. aureus.Methods:S. aureusbacteremia (SAB) was defined as hospital acquired if the first positive blood culture was performed more than 48 hours after admission. Other SABs were classified as healthcare associated or community acquired according to the definition proposed by Friedman et al. When available, strains of methicillin-resistantStaphylococcus aureus(MRSA) were analyzed by pulsed-field gel electrophoresis (PFGE).Results:Eighty-two patients were considered as having community-acquired bacteremia according to the Centers for Disease Control and Prevention (CDC) classification. Of these 82 patients, 56% (46) had healthcare-associated SAB. MRSA prevalence was similar in patients with hospital-acquired and healthcare-associated SAB (41% vs 33%;P> .05), but significantly lower in the group with community-acquired SAB (11%;P< .03). PFGE of MRSA strains showed that most community-acquired and healthcare-associated MRSA strains were similar to hospital-acquired MRSA strains. On multivariate analysis, Friedman's classification was more effective than the CDC classification for predicting MRSA.Conclusion:These results support the call for a new classification for community-acquired bacteremia that would account for healthcare received outside the hospital by patients with SAB.

scholarly journals Multiplex Polymerase Chain Reaction Based Typing of Staphylococcal Chromosomal Cassette mec of Methicillin Resistant Staphylococcus aureus from Selected Hospitals in Lahore

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Romeeza T ◽  
Naeem R ◽  
Nadeem A
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Sccmec Type ◽  
Meca Gene ◽  
Methicillin Resistant ◽  
Different Types ◽  
Type Ia ◽  
Polymerase Chain ◽  
Sccmec Types

Introduction: Staphylococcus aureus is one of the leading causes of nosocomial infections. Prevalence of methicillin resistant Staphylococcus aureus (MRSA) has been reported in up to 42% of isolates in Pakistan. Methicillin resistance is encoded by the mecA gene and it is transferred by a unique genetic vector called staphylococcal chromosomal cassette (SCCmec). Depending upon the selection pressures of antibiotics, different types of SCCmec elements may prevail in different parts of the world. Materials and Methods: Therefore, this study was designed to fi nd out the major SCCmec types present in selected hospitals of Lahore. For this purpose thirty fi ve MRSA isolates were collected. These strains were reconfi rmed and SCCmec types were determined by multiplex PCR. Results: It was found that 21 (60%) isolates possess SCCmec type IA while 14 (40%) isolates possess SCCmec type IIC. Conclusion: These cassettes are shown to be multiresistant and have not been reported in other Asian countries so far.

scholarly journals An overview of Staphylococcus epidermidis and Staphylococcus aureus with a focus on developing countries

2015 ◽  
Vol 9 (06) ◽  
pp. 547-550 ◽  
Author(s):  
Daniela Chessa ◽  
Giulia Ganau ◽  
Vittorio Mazzarello
Keyword(s):  
Staphylococcus Aureus ◽  
Developing Countries ◽  
Antibiotic Resistance ◽  
Life Cycle ◽  
Virulence Factors ◽  
Staphylococcus Epidermidis ◽  
Methicillin Resistance ◽  
The World ◽  
Spa Gene ◽  
And Staphylococcus Aureus

Most nosocomial infections by Staphylococcus epidermidis and Staphylococcus aureus have gained considerable attention due to an increase of infections caused by these strains that have been reported in recent years throughout the world. Most notably, it is important to underline the presence of S. epidermidis and S. aureus in the human epithelia microflora and to highlight that it is impossible to eradicate them from humans. There are various virulence factors that normally sustain the infection life cycle, such as antibiotic resistance (methicillin resistance). Furthermore, it is important to evaluate the usefulness of typing the spa gene from isolated strains in order to study genotypes and geographical distributions. In the present review, different cases related to patients infected by Staphylococci and an overview of this problem worldwide are reported.

scholarly journals Changes in the Prevalence of Methicillin Resistance Among Healthcare-Associated Staphylococcus aureus Infections, 2009–2018

2020 ◽  
Vol 41 (S1) ◽  
pp. s160-s162
Author(s):  
Lindsey M. Weiner-Lastinger ◽  
Minn M. Soe ◽  
Jonathan R. Edwards ◽  
Margaret A. Dudeck
Keyword(s):  
Staphylococcus Aureus ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Methicillin Resistance ◽  
Bloodstream Infections ◽  
Surgical Site Infections ◽  
The United States ◽  
Logistic Function ◽  
Tract Infections ◽  
Healthcare Associated

Background:Staphylococcus aureus has long been an important cause of healthcare-associated infections (HAIs) and remains the second most common HAI pathogen in the United States. Often resistant to several antibiotics, S. aureus infections are difficult to treat and can leave patients at risk for serious complications such as pneumonia and sepsis. HAI pathogens and their antimicrobial susceptibility testing (AST) results have been reported to NHSN since its inception in 2005. Previous NHSN surveillance reports have presented national annual benchmarks for antimicrobial resistance phenotypes, such as methicillin-resistant S. aureus (MRSA). Whether there have been any significant changes over time in the prevalence of methicillin resistance among S. aureus infections reported to NHSN has not been previously assessed. Methods:S. aureus AST data from central-line–associated bloodstream infections, catheter-associated urinary tract infections, and inpatient surgical site infections reported from acute-care hospitals between 2009 and 2018 were analyzed. S. aureus was defined as MRSA if it was reported as resistant to oxacillin, cefoxitin, or methicillin. A national percentage resistant (%R) was calculated for each year as the number of resistant pathogens divided by the number of pathogens tested for susceptibility multiplied by 100. A generalized linear mixed model with logistic function was created to evaluate annual changes in the percentage resistant. Several patient-level and hospital-level characteristics were assessed as potential covariates. To account for differential baseline %R values between individual hospitals, specification of random intercept and slope were used during model creation. Differences in the trend of %R between HAI types were assessed using interaction terms. Data were analyzed using SAS v 9.3 software, and P < .05 was considered significant. Results: Overall, 3,317 hospitals reported at least 1 S. aureus pathogen tested for susceptibility between 2009 and 2018. The national unadjusted %R decreased from 49.2% (2009) to 41.2% (2018), with similar decreases seen in each HAI type (Table 1). After adjusting for significant covariates, a statistically significant annual 3% decrease in the prevalence of resistance was observed (Fig. 1). Significant differences between HAI types did not exist. Conclusions: The percentage of healthcare-associated S. aureus resistant to oxacillin, cefoxitin, or methicillin has declined consistently over the past 10 years. Continued efforts in infection prevention and antimicrobial stewardship are vital to sustaining this decline.Funding: NoneDisclosures: None

scholarly journals Genetic Diversity of Methicillin-Resistant Staphylococcus Aureus Among Japanese Inpatients in the Early 1980s

2020 ◽  
Author(s):  
Hui Zuo ◽  
Yuki Uehara ◽  
Yujie Lu ◽  
Takashi Sasaki ◽  
Keiichi Hiramatsu
Keyword(s):  
Staphylococcus Aureus ◽  
Population Structure ◽  
Methicillin Resistance ◽  
The United States ◽  
Type I ◽  
Methicillin Resistant ◽  
Global Pandemic ◽  
Mrsa Strains ◽  
Healthcare Associated ◽  
Genotypic Characteristics

Abstract Background: Methicillin-resistant Staphylococcus aureus (MRSA) was recognized as a serious nosocomial pathogen in Japan starting in the early 1980s. Limited genotypic characteristics on healthcare-associated MRSA (HA-MRSA) associated with “hospital MRSA panics” in Japan in this era. Therefore, this study aimed to determine the characteristics of Japanese HA-MRSA strains in the early 1980s and their linkage with current MRSA strains.Methods: For 194 S. aureus strains isolated in the early 1980s, we determined methicillin resistance phenotypically and genotypically and performed multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, and whole-genome sequencing. Results: Twenty mecA-positive MRSA (10.3%), 8 mecA-negative MRSA (4.1%) and 3 mecA-positive methicillin-susceptible S. aureus (MSSA) (1.5%) strains were identified. The frequent sequence type (ST) was ST30 (n=11), followed by ST5 (n=8), ST81 (n=4), and ST247 (n=3). Rates of SCCmec types I, II, and IV were 65.2%, 13.0%, and 17.4%, respectively. ST30-SCCmec I (n=7) and ST5-SCCmec I (n=5) were predominant genotypes. Only two strains exhibited tst-positive ST5-SCCmec II, which is the current Japanese HA-MRSA genotype. Moreover, 73.3% of SCCmec type I strains were susceptible to imipenem compared with SCCmec type II strains (0%). All ST30 strains shared a common ancestor with strain 55/2053, which resulted in a global pandemic of Panto-Valentine leukocidin (PVL)-positive and penicillin-resistant MSSA spread in Europe and the United States in the 1950s. Conclusions: Our results demonstrated the heterogeneous population structure of Japanese HA-MRSA during the early 1980s, which comprised diverse clones that are mostly rare in recent years. The shift to the current homogenous population structure of HA-MRSA strains consisting of tst-positive ST5-SCCmec II might result from the clinical introduction of new antimicrobials including imipenem.

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