Epidemiology and molecular characteristics of methicillin-resistantStaphylococcus aureus from skin and soft tissue infections in Shiraz, Iran

Abstract

IntroductionAmong staphylococcal species, Staphylococcus aureus has been shown as a clinically relevant human pathogen, and in many individuals it may lead to asymptomatic colonization (1). Various infections from skin and soft tissue infections (SSTIs) to life-threatening infections like endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, and sepsis are caused by this bacterium (2). Carriage of S. aureus is a risk factor for subsequent infection in various settings. Recent investigations suggest that nares-only screening may underestimate the prevalence of S. aureus colonization, and accurate determination requires sampling from other body sites (3). The spread of antibiotic resistance among strains of S. aureus has been dramatically elevated, such that methicillin-resistant S. aureus (MRSA) is recognized as a nosocomial pathogen worldwide. MRSA strains were once exclusively limited to hospital care; however, after outbreaks of infection in hospitals and health care facilities they have increasingly been detected among patients in the community who lack conventional risk factors for MRSA infection (4). MRSA represents a significant cause of morbidity and mortality in both hospital and community settings, which raises serious concerns in the treatment of staphylococcal infections; hence, the accurate and early determination of methicillin resistance is a necessity for the prognosis of S. aureus infections (5). Most MRSA and some methicillin-susceptible S. aureus (MSSA) isolates produce Panton-Valentine leukocidin (PVL), a pore-forming toxin consisting of two subunits S (LukE) and F (LukD) (6,7). It has become increasingly important as a virulence factor in necrotizing SSTIs such as furuncle and pneumonia (6). Both MSSA and community-associated MRSA can express PVL (8). Contrary to European countries (9), PVL-associated infections are increasing in some regions of Iran (10). This study aimed to assess the microbiological, epidemiological, and clinical features of purulent skin infections caused by S. aureus in Shiraz, southern Iran.Background/aim: Panton-Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) infections are increasing in some regions of Iran. The aim of the current study was to assess the epidemiology and molecular characteristics of S. aureus isolated from patients with skin infections in Shiraz, Iran.Materials and methods: Swab samples were obtained from patients admitted to the skin and burn units of hospitals. The medical records of each patient were collected via questionnaire. All staphylococcal isolates were collected and examined by conventional methods for detecting S. aureus strains. PCR was used to detect S. aureus harboring the mecA and pvl genes.Results: Out of 243 staphylococcal isolates, 55 (22.6%) S. aureus and 91 (37.4%) S. epidermidis were detected. Of the 45 patients, 21 (46.7%) were S. aureus carriers. The mecA gene was identified in 60% of S. aureus isolates, and the rest were sensitive to methicillin. Of the S. aur...

Correlation of methicillin resistance and virulence genes of <i>Staphylococcus aureus</i> with infection types and mode of acquisition in Sofia, Bulgaria

“…Four sets of multiplex PCR were used to detect the genes of interest with the following mixes; Mix I contain primers for hlg, sea, sed and tst genes; Mix II contains primers, Sau 327 and Sau 1645 for specific S. aureus 23S rRNA gene, and primers for enterotoxin seg; Mix III contains primers for seh, see and sej genes; and Mix IV contains primers for cna, seb, sec, and sei genes. Monoplex PCR was used for Mix V and Mix VI which contains primers for mecA and mecC respectively, according to the criteria and protocols (4,22) presented in Table 1.…”

“…This bacterial specie is a clinically relevant human and animal pathogen. In humans, S. aureus is a major cause of both community acquired (CA) and nosocomial or healthcare-associated (HA) infections such as skin, soft tissue and bone infections, postoperative wound infections, upper respiratory tract infections, pneumonia, bacteraemia and endocarditis (1)(2)(3)(4)(5). S. aureus is also among the most common pathogens causing food-borne diseases (6)(7)(8)(9)(10) and is associated with suppurative diseases in animals such as mastitis, septic arthritis, endocarditis, osteomyelitis, urinary tract infections and sepsis (7,11,12).…”

“…The super-antigens (SAgs), TSST-1 and SEs, which stimulate polyclonal proliferation of T lymphocytes and noneffective immune responses are the most important toxigenic determinants and virulence mediators in S. aureus infections (6,10,17,18). Methicillin resistant S. aureus (MRSA) can form a strong biofilm and easily colonize mucosa, endovascular catheters and/or implants, which is one reason why it causes chronic, recurrent or invasive nosocomial infections (4,19,20). This aim of this study is to assess the correlation between methicillin resistance, and virulence genes encoding predominantly SAgs, with invasive or noninvasive and CA or HA types of infection due to S. aureus.…”

Molecular-genetic Method for Fast Direct Detection of Staphylococcus Aureus and Methicillin Resistance in Blood Cultures and Punctures

“…1). 1 The primer sequences were verified for specificity using the Basic Local Alignment Search Tool (BLAST) program available from the NCBI website (Bethesda, MD) (http//:www.nbi.nlm.nih.gov/BLAST). DNA was amplified after optimisation of the PCR protocol: initial denaturation at 94°C for 5 min and 35 cycles of denaturation at 94°C for 2 min; annealing at 57°C for 2 min; extension at 72°C for 1 min; final elongation at 72°C for 7 min.…”

“…Methicillin resistant Staphylococcus aureus (MRSA) and methicillin resistant coagulase-negative staphylococci (MRCoNS), except when the latter are contaminants, are the major causes of life-threatening bloodstream infections (BSI), endocarditis, postoperative soft tissue infections, osteomyelitis, septic arthritis, metastatic abscesses, especially nosocomial ones, and pose a global problem for public health. [1][2][3] The virulence arsenal of staphylococcal isolates differs depending on the bacterial species and the coagulase-positive S. aureus has been proved to be the most virulent species. The most frequent severe BSI infections caused by this pathogen are due to various extracellular products, e.g.…”