Molecular characteristics of methicillin-resistant Staphylococcus aureus isolates from hospital and community environments in northeastern Brazil

ABSTRACT This study characterized 30 MRSA isolates from intensive care unit (ICU) environment and equipment surfaces and healthy children. The SCCmec types I, IVa and V were detected in HA-MRSA isolates while CA-MRSA showed the SCCmec type IVa and V. Most isolates were classified as agr group II. All isolates presented the sei gene, and only HA-MRSA were positive for etb e tst genes. Three genotypes were related to Pediatric (ST5/SCCmecIV) and Berlin (ST45/SCCmecIV) clones. The present study showed molecular similarity between CA- and HA-MRSA isolates in hospital and community settings in a Brazilian region.

Phenotypic and Genotypic Characterization, and Detection of PVL Encoding Gene in Methicillin Resistant Staphylococcus Aureus Strains Isolated From Patients Admitted to a Tertiary Hospital In Kuantan, Malaysia

@#Introduction: Methicillin-resistant Staphylococcus aureus is globally a major public health threat. Resistance to methicillin originates from a modified protein (PBP2a) encoded by the mecA gene. The PVL gene as an important virulence factor increases the pathogenicity of MRSA. Epidemiology and characteristics of MRSA differ in different geographical regions. This study was conducted to characterize and determine the antibiotic susceptibility profile of MRSA strains isolated from patients in Hospital Tengku Ampuan Afzan, Pahang, Malaysia and to detect the presence of the mecA and PVL genes in the isolates. Materials and methods: In this study a total of 36 isolates of MRSA have been collected during a period of three months (1stFebruary –30thApril 2018). The susceptibility pattern of the isolates to ten different commonly used antibiotics were determined and the target genes were addressed by real-time PCR experiment. Results: Based on the identifying criteria, 44.4% of the isolates were CA-MRSA, and 55.5% were HA-MRSA. Resistance to oxacillin, cefoxitin and penicillin was 100%, gentamicin 88.8%, erythromycin 33.3%, tetracycline 77.7%, trimethoprim-sulfamethoxazole 61.1%, clindamycin 13.8%, chloramphenicol 11.1%, but no resistant strain of vancomycin was detected. Most of the isolates were resistant to more than three groups of antibiotics. Realtime PCR revealed that all the isolates were mecA positive and 4 isolates were PVL-positive. PVL-positive strains were CA-MRSA and susceptible to clindamycin. Conclusion: The study confirms multi-drug resistant MRSA in the study area, and shows that resistance to methicillin is mecA mediated. PVL carrier strains were present and related to CA-MRSA strains of the isolates.

Benzalkonium chloride effectiveness as a disinfectant against hospital associated methicillin-resistant Staphylococcus aureus (HA-MRSA)

Aims@#Benzalkonium chloride is used to disinfect hospital instruments to prevent nosocomial infection caused by microorganisms, such as Methicillin Resistant Staphylococcus aureus (MRSA). There are strains of MRSA isolated from hospitals that were found to be resistant towards benzalkonium chloride. This research was aimed to compare the affectivity of different concentrations of benzalkonium chloride to inhibit the growth of Hospital-Associated MRSA (HA-MRSA) and determine the Minimum Inhibitory Concentration (MIC) of benzalkonium chloride against HA-MRSA. @*Methodology and results@#The samples were five HA-MRSA isolates obtained from Dr. Soetomo Hospital Surabaya. It was identified by amplification of SCCmec genes. The HA-MRSA with SCCmec type III was divided into six flasks based on the concentration of benzalkonium chloride in their inoculation media (0 μg/mL, 0.625 μg/mL, 1.25 μg/mL, 2.5 μg/mL, 5 μg/mL, and 10 μg/mL). The growth of HA-MRSA in media was determined by the number of colonies after treatment. The result showed that the MIC of benzalkonium chloride for HA-MRSA was 5 μg/mL, where no growth of bacterial was observed. There was significant difference in MRSA colony count between different groups of benzalkonium chloride concentrations (p = 0.001), and there was negative correlation between benzalkonium chloride concentration and HA-MRSA growth (p = 0.0001 and r = -0.880). @*Conclusion, significance and impact of study@#The concentration of benzalkonium chloride influences the growth of HA-MRSA. The higher the concentration, the fewer HA-MRSA growth. Application of benzalkonium chloride according to MIC will prevent HA-MRSA resistance towards benzalkonium chloride.

Retrospective analysis of methicillin-resistant staphylococcus aureus skin and soft tissue infection among patients admitted at an academic university hospital from 2011 to 2015: A five-year review

Introduction@#The emergence of methicillin-resistant Staphylococcus aureus (MRSA) is a challenge in the management of skin and soft tissue infections (SSTIs). @*Objective@#To describe the epidemiology of MRSA SSTIs among admitted patients at the University of Santo Tomas Hospital (USTH).@*Methods @#This was a retrospective study of inpatients with MRSA SSTIs from 2011-2015. MRSA infections were classii ed as community-associated (CA-MRSA) and healthcare-associated (HA-MRSA). Demographic characteristics, clinical proi le, comorbidities, complications, risk factors, antibiotic susceptibility and resistance, treatment used, and clinical outcome were determined.@*Results@#Out of the 331 inpatients with Staphylococcus aureus SSTIs, 211 had MRSA with a prevalence of 63.7%, 80.1% of MRSA were CAMRSA while 19.9% were HA-MRSA. The mean age was 41.58 years with male predominance. The majority presented with abscess (62.9%), on the legs (21.8%). The abscess was signii cantly associated with CA-MRSA while infected wounds, previous hospitalization, and surgery were correlated with HA-MRSA. Growing resistance to ciprol oxacin, tetracycline, macrolides, co-trimoxazole, and clindamycin was noted. A low percentage of resistance to vancomycin and linezolid was observed. Almost all cases improved with appropriate antibiotic therapy and 3.3% mortality@*Conclusion@#More than half of the patients with Staphylococcus aureus SSTIs had MRSA. and were mostly CA-MRSA and males. Abscess on the leg was the common presentation and signii cantly associated with CA-MRSA. Infected wounds, previous hospitalization, and surgery were associated with HA-MRSA. There was high resistance of MRSA to ciprol oxacin and tetracycline while low resistance to vancomycin and linezolid. Almost all improved with appropriate treatment.

Molecular characterization of community- & hospital-acquired methicillin-resistant & methicillin-sensitive Staphylococcus aureus isolates in Sikkim.

Background & objectives: The two major genotypic markers that distinguish community acquired (CA) from hospital acquired (HA) methicillin resistant staphylococcus aureus (MRSA) isolates are the architecture of mobile genetic element (SCCmec type) and presence of panton valentine leukocidin (PVL) toxin. This study was conducted to determine the molecular characteristics of CA- and HA- MRSA and methicillin sensitive S. aureus (MSSA) isolates in Sikkim. Methods: A total of 150 clinical isolates of S. aureus isolated from various clinical specimens were subjected to duplex (mec-A and pvl gene) and multiplex (SCCmec typing) PCR. Results: of the 150 isolates, 53 (35.33%) and 66 (44%) were positive for mec-A (MRSA) and pvl genes, respectively. Thirty eight (25.33%) met the definition of CA-MRSA and 15 (10%) of HA-MRSA and the remaining 63 (42%) and 34 (22.66%) as CA- and HA-MSSA, respectively. No significant difference was seen in the distribution of PVL toxin in MRSA and MSSA isolates, but it was significantly (P<0.001) high in overall MRSA isolates than in MSSA. The majority of the MRSA isolates showed a double amplification band of SCCmec type III plus V (54.71%), and only a fewer isolates were amplified by single DNA fragments of type I (1.88%), III (3.77%), IVa (1.88%) and V (11.32%). SCCmec types I, III, IVa, were found only in HA-MRSA isolates, whereas type V in both the CA- and HA-MRSA. AST pattern showed that 18.42 per cent (7/38) and 46.66 per cent (7/15) were multidrug resistant (MDR)-CA-MRSA and MDR-HA-MRSA, respectively. Interpretation & conclusions: The present results show that SCCmec type V MRSA has been on the rise, and genotypic markers such as pvl gene detection used for the differentiation of these clinically distinct isolates of MRSA may not be reliable.

Clinical and Diagnostic Significance of Methicillin-resistant Staphylococcus aureus Infection in Bangladesh: A Systematic Review.

Background: Accurate diagnosis of Methicillin-resistant Staphylococcus aureus (MRSA) is essential for the clinician. In Bangladesh MRSA creates a great problem for the treatment of infection. Objective: The purpose of the present study was to observe the clinical and diagnostic significance of MRSA infection in Bangladesh. Design: Systematic review of published articles in Bangladesh. Data Sources: PubMed (Medline), Embase, Scopus, Web of Science, the Cochrane Library, and the World Health Organization (WHO) Regional Databases (African, eastern Mediterranean, Latin American and Caribbean, western Pacific, and southeast Asian regions) as well as Google Scholar, Banglajol, Asiajol. Review Methods: The search was restricted to full articles published from January 2000 (publication date of the first study identified by the research) to December 2013. Studies were excluded that did not provide appropriate data on the prevalence of MRSA. Only English language was applied. Result: A total number of 125 studies were identified during systematic review which were relevant to the present research question and among these only 14 studies were met the criteria for analysis. The level of evidence and freedom from bias of these studies were generally low. MRSA was diagnosed phenotypic in most of the articles. Majority were isolated from skin wound. The isolation rate of MRSA among all culture isolates ranged from 4.8-78.7%. From all studies diagnosis of MRSA infection was done from hospital setting; however, only two studies had been reported from community settings though the CDC definition was not followed in either study. Conclusion: Significance of methicillin-resistant Staphylococcus aureus infection in Bangladesh is very high leading to a huge clinical as well as laboratory burden in the heath care facilities as well as in the community settings of Bangladesh.

The multifaceted resources and microevolution of the successful human and animal pathogen methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important bacterial pathogens based on its incidence and the severity of its associated infections. In addition, severe MRSA infections can occur in hospitalised patients or healthy individuals from the community. Studies have shown the infiltration of MRSA isolates of community origin into hospitals and variants of hospital-associated MRSA have caused infections in the community. These rapid epidemiological changes represent a challenge for the molecular characterisation of such bacteria as a hospital or community-acquired pathogen. To efficiently control the spread of MRSA, it is important to promptly detect the mecA gene, which is the determinant of methicillin resistance, using a polymerase chain reaction-based test or other rapidly and accurate methods that detect the mecA product penicillin-binding protein (PBP)2a or PBP2’. The recent emergence of MRSA isolates that harbour a mecA allotype, i.e., the mecC gene, infecting animals and humans has raised an additional and significant issue regarding MRSA laboratory detection. Antimicrobial drugs for MRSA therapy are becoming depleted and vancomycin is still the main choice in many cases. In this review, we present an overview of MRSA infections in community and healthcare settings with focus on recent changes in the global epidemiology, with special reference to the MRSA picture in Brazil.

Epidemiological and molecular characterization of community and hospital acquired Staphylococcus aureus strains prevailing in Shenyang, Northeastern China

In order to obtain adequate information for the treatment of methicillin resistant Staphylococcus aureus (MRSA) infections, it is crucial to identify trends in epidemiological and antimicrobial resistance patterns of local S. aureus strains. Community and hospital acquired S. aureus isolates (n = 202) were characterized using staphylococcal cassette chromosome mec (SCCmec) typing, pulse field gel electrophoresis (PFGE) analysis, spa typing and minimal inhibitory concentration (MIC) determination. The prevalence of the Panton-Valentine leukocidine (pvl) and several antibiotic resistance genes among the isolates were also detected by PCR. All of the S. aureus isolates were susceptible to vancomycin, daptomycin and linezolid. Three hospital isolates were resistant to teicoplanin while 14 showed intermediate resistance to teicoplanin. The resistance patterns of community-acquired MRSA (CA-MRSA) isolates to other antimicrobials were similar to those of hospital-acquired MRSA (HA-MRSA) isolates except for clindamycin and gentamicin. There was excellent correlation between phenotypes and genotypes in the determination of S. aureus resistance to erythromycin, gentamicin, and tetracycline. The SCCmec type II and SCCmec type IV were the predominant types detected in hospital and community isolates, respectively. The most frequently encountered spa types were t002 and t030 both in HA-and CA-MRSA isolates. Pulsotype A was the most predominant pulsotype identified among the isolates tested, followed by pulsotype B. Seventy-two hospital isolates (19 HA-MRSA and 53 HA-MSSA) and 10 CA-MRSA were positive for the pvl gene. This study shows that the combination of susceptibility testing and various molecular methods has provided useful information on the antibiotic resistance and molecular diversity of S. aureus in a specific region of China. The high proportion of pvl positive MSSA and MRSA isolates observed in this study indicates that adequate measures are needed to curtail the spread of those MRSA and MSSA clones prevailing both in hospital and the community.

Incidence of Community-associated Methicillin-resistant Staphylococcus aureus Infections in a Regional Hospital / Journal of Rural Medicine

<b>Background and Objective:</b> Since the early 2000s, the incidence of methicillin-resistant <i>Staphylococcus aureus</i> (MRSA) infections among the community of people lacking known healthcare risk factors has increased. This MRSA infection is referred to as community-associated MRSA (CA-MRSA) infection and is distinct from hospital-associated MRSA (HA-MRSA) infection, which occurs among people with known healthcare risk factors. Understanding the epidemiology of CA-MRSA infections is critical; however, this has not been investigated in detail in Japan. Our objective was to investigate the incidence of CA-MRSA infections in a regional hospital. <BR><b>Patients and Methods:</b> We investigated CA-MRSA isolates and infections in a rural regional hospital by reviewing medical records of one year. Infections were classified as CA-MRSA if no established risk factors were identified. <BR><b>Results:</b> During 2008, 31 <i>Staphylococcus aureus</i> (<i>S. aureus</i>) isolates were detected in 29 unique patients, with 1 methicillin-sensitive <i>S. aureus</i> (MSSA) isolates obtained from 19 patients (66%) and MRSA obtained from 10 patients (34%). In the 10 patients with MRSA, the number of HA-MRSA and CA-MRSA cases were nine (32% of patients with <i>S. aureus</i> isolates) and one (3%), respectively. The patient with CA-MRSA was diagnosed with cellulitis due to CA-MRSA. All nine patients with HA-MRSA exhibited colonization. <BR><b>Conclusion:</b> We observed a CA-MRSA case in a regional hospital in Japan, suggesting that incidence trends of CA-MRSA should be considered in future research and treatment.

Characterisation of methicillin resistant S. aureus strains and risk factors for acquisition in a teaching hospital in northeast India.

Purpose: A point prevalence study was carried out in a teaching hospital in Assam to characterise S. aureus strains, establish the rate of colonisation of methicillin resistant S. aureus (MRSA) and associated risk factors for its acquisition. Materials and Methods: Antibiogram-Resistogram profile was done by BSAC standardized disc sensitivity method; Phage and RFLP typing were carried out by the PHLS, London. Results: Single MRSA strain resistant to multiple classes of anti-staphylococcal antibiotics dominated the hospital. The MRSA colonisation rate was found to be 34% (n=29) and 18% (n=80) in orthopaedics and surgery, respectively and only ~1% (n=73) in the medical units. Exposure to ciprofloxacin and surgery were risk factors but duration of hospital stay was not. In contrast, meticillin sensitive S. aureus (MSSA) strains were usually distinct strains and sensitive to most of the anti-staphylococcal antibiotics including 18% to penicillin. Conclusions: The MRSA strain prevalent in the hospital phenotypically resembles the predominant Asian strain viz., Brazilian/Hungarian strains (CC8-MRSA-III). Duration was not a risk factor, which suggests that in absence of exposure to specific antimicrobials, even in a hospital with no or little infection control intervention, a vast majority remain free from MRSA. This underlines the importance of rational prescribing empirical antibiotics.

Staphylococcus aureus resistente a meticilina: bases moleculares de la resistencia, epidemiología y tipificación / Methycillin-resistant Staphylococcus aureus: molecular bases of resistance; epidemiology, and typification

Staphylococcus aureus es responsable de un amplio espectro de cuadros clínicos que van desde infecciones en la piel y los tejidos blandos hasta enfermedades sistémicas muy graves que amenazan la vida; tiene gran importancia en la comunidad y está comúnmente implicado en infecciones nosocomiales. Además, un alto porcentaje de individuos está colonizado por S. aureus, lo cual constituye un factor de riesgo para su diseminación. S. aureus tiene gran capacidad de adquirir resistencia a los antimicrobianos y en la actualidad se encuentran cepas resistentes a la mayoría de los antibióticos disponibles; en particular, su resistencia a la meticilina, inicialmente en el ambiente hospitalario (HA-MRSA) y posteriormente en la comunidad (CA-MRSA), ha dificultado aún más el control mundial de este microorganismo. Los estudios de epidemiología molecular han permitido entender mejor las relaciones evolutivas de las cepas y definir el origen de los clones durante brotes epidémicos. En Colombia se sabe poco sobre la epidemiología de S. aureus y aún menos sobre su comportamiento en la comunidad. Por ello, estudios de vigilancia epidemiológica que involucren la tipificación molecular de las cepas permitirán comprender mejor su epidemiología y establecer estrategias más certeras de tratamiento y control.

Staphylococcus aureus is responsible for a wide variety of clinical manifestations ranging from skin and soft tissue infections to severe systemic and life threatening diseases; it is of relevance in the community and is commonly associated with nosocomial infections. Additionally, a high percentage of the population is colonized by S. aureus, which constitutes a risk factor for its dissemination. S. aureus has great capacity to acquire antimicrobial resistance, and currently there are resistant strains to the majority of available antibiotics; in particular, its resistance to methycillin, initially in the hospital environment (Hospital associated methycillin resistant S. aureus, HA-MRSA) and later in the community (Community acquired methycillin resistant S. aureus, CA-MRSA), has made even more difficult the worldwide control of this microorganism. Molecular epidemiological studies have provided a better understanding of the evolutionary relationships of the strains, and the definition of the clonal source during epidemic outbreaks. In Colombia, very little is known about S. aureus epidemiology and even less about its behavior in the community. Therefore, studies based on epidemiological surveillance, involving molecular typing, will lead to a better understanding of its epidemiology, making it possible the design of more assertive control strategies.