A Review of Staphylococcal Cassette Chromosome mec (SCCmec) Types in Coagulase-Negative Staphylococci (CoNS) Species (original) (raw)
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Indian Journal of Medical Microbiology, 2018
Original Article inTrOduCTiOn Methicillin-resistant coagulase-negative staphylococci (MR-CoNS) are now an emerging threat to the society, i.e., community as well as nosocomial environment; as an opportunistic pathogen, it persists and proliferates in diverse environmental sources. [1] Infections caused by CoNS are the most commonly isolated pathogens from the neonatal intensive care unit (NICU), and hence, Staphylococcus haemolyticus and Staphylococcus epidermidis became the most frequent causative agents of leading NICU infections over the past decades. [2,3] Staphylococcus sciuri also being the important human pathogens are responsible for endocarditis, peritonitis, septic shock, urinary tract infection, pelvic inflammatory disease and wound infections, with an exception for Staphylococcus saprophyticus and Staphylococcus lugdunensis where they rarely attack a healthy host, due to their nonaggressive virulence properties. [2] MR-CoNS in the environment serve as a reservoir of genetically diverse staphylococcal cassette chromosome mec (SCCmec) types, which function as a vehicle for the transfer of resistance genes horizontally to other organisms. [4] Till date, 12 different SCCmec types (I-XII) have been discovered in Staphylococcus aureus, and it was also reported that many composite SCCmec elements have been found in MR-CoNS. [5] Based on such diversity, five SCCmec types (I-V) have also been described in CoNS isolates. [6] Genetic diversity of SCCmec types varies with environmental locations as well as with their introduction of newly evolved Introduction: Coagulase Negative Staphylococci, the most commonly isolated pathogen are becoming emerging threats to the community as well as to the nosocomial environment. The present study underscores the distribution of Staphylococcal cassette chromosome mec (SCCmec) types among Methicillin resistant Coagulase Negative Staphylococci from the environmental origin. Methods and Materials: Environmental and food sample (n = 460) from different location of northeastern region of India were collected for a period of one year and were phenotypically and genotypically screened using cefoxitin disc and PCR techniques for mecA and mecC gene detection. All the MR-CoNS isolates possessing mecA gene were subjected to 16srDNA sequencing for species identification. SCCmec typing was determined by evaluating using primer sets from type I to type V. Antibiotic susceptibility testing was performed for all the isolates. Statistical analysis with chi-square test using SPSS-21 statistical software. Results: Methicillin resistance shown by one hundred forty three isolates were carried out for molecular analysis, among them 53.84% serves as mecA carrier. Distribution of Staphylococcus haemolyticus was more frequent and was found that SCCmec types II and V were predominant among the study isolates. Linezolid was the drug of choice for the CoNS isolates. Statistical analysis showed an insignificant result for the tested antibiotics and SCCmec types. Conclusion: This study therefore interprets the relative importance of SCCmec types among MR-CoNS isolates.
2020
Objective(s): Methicillin-resistant coagulase-negative Staphylococci (MR-CoNS) are recognized as one of the major causes of healthcare-associated infections in hospitals. The present investigation aimed to study the prevalence of Staphylococcal cassette chromosome mec (SCCmec) types, along with aminoglycoside modifying enzymes (AMEs) genes in the nasal carriage of MR-CoNS in the north-west of Iran. Materials and Methods: To assess the potential of coagulase-negative Staphylococci as hidden reservoirs for antibiotic resistance, we analyzed the antimicrobial susceptibility of MR-CoNS using the disk diffusion method. In addition, PCR and multiplex PCR assays were performed to determine the prevalence of AME encoding genes and SCCmec types in methicillin-resistant coagulase-negative Staphylococci isolates. Results: A total of 51 MR-CoNS isolates were recovered from the anterior nares of healthcare workers. The observed resistance rates to tobramycin, gentamicin, cotrimoxazole, kanamycin...
Journal of Medical Microbiology, 2007
Coagulase-negative staphylococci (CoNS) are now recognized as the aetiological agents of an important range of infections in humans. Most developed countries have reported an increase in CoNS infections in hospitalized patients that are resistant to meticillin and other antibiotics. Staphylococcal cassette chromosome mec (SCCmec) typing is essential for understanding the molecular epidemiology of meticillin-resistant Staphylococcus strains. SCCmec elements are currently classified into types I to VI based on the characteristics of the mec and ccr gene complexes and are further classified into subtypes according to their ‘junkyard DNA’ region. We evaluated the distribution of SCCmec types in CoNS from patients attending the Hospital de Clínicas de Porto Alegre over the period August 2004–December 2005. Among the 129 bloodstream isolates, 36 (27.9 %) harboured SCCmec type I, 4 (3.0 %) harboured SCCmec type II, 67 (52 %) harboured SCCmec type III, 1 (0.8 %) harboured SCCmec type IV and...
Epidemiology and Infection, 2010
Coagulase-negative staphylococci (CNS) are increasingly recognized to cause clinically significant infections, with S. epidermidis often cited as the third most common cause of nosocomial sepsis. Among CNS, there is a high prevalence of methicillin resistance associated with staphylococcal cassette chromosome (SCCmec) elements. Although identical SCCmec types can exist in S. aureus and CNS, some novel classes of SCCmec may be unique to CNS. Differences in the accuracy of identification of CNS species and use of non-standardized methods for the detection of methicillin resistance have led to confusing data in the literature. In addition to the review of SCCmec in CNS, in this paper we report a 2-year surveillance of methicillin-resistant CNS in a tertiary-care hospital in Guadalajara, Mexico.
Turkish Journal of Medical Sciences
To describe the true coagulase-negative staphylococci (CoNS) bacteremia rate compared with contaminants, and to determine the SCCmec types in methicillin-resistant staphylococci and evaluate the diversity between methicillin-resistant CoNS (MRCoNS) and methicillin-resistant Staphylococcus aureus (MRSA) isolates during a 10-month study period. Materials and methods: Th e true CoNS bacteremia or bloodstream infection episode was defi ned on the basis of previous studies on CoNS bacteremia and the defi nitions of the Centers for Disease Control and Prevention. SCCmec types were determined by using the real-time PCR method. A total of 357 staphylococci isolates, including 313 CoNS and 44 S. aureus, were obtained from 462 positive blood culture samples. Results: A total of 249 CoNS bacteremia episodes in 231 patients were evaluated. Of these episodes, 45 (18.1%) in 41 patients were considered to be true CoNS bacteremia, whereas 204 in 190 patients were found to be contaminant. In the present study, all of the MRSA isolates harbored only SCCmec type III, but MRCoNS strains harbored diff erent SCCmec types and SCCmec type IV was the most prevalent. Conclusion: Th e true CoNS bacteremia rate was consistently within the range reported in the literature. We also concluded that MRCoNS isolates carrying mostly SCCmec type IV elements may not be related to the presence of MRSA isolates carrying only SCCmec type III element in our institution.
BMC Microbiology, 2014
Background: Coagulase-negative staphylococci (CoNS) are opportunistic pathogens found as colonisers of the human gut. This study was carried out to examine the genetic resistance mechanisms in faecal isolates of CoNS. The study investigated 53 non-duplicate CoNS isolates obtained from the fresh stool samples of apparently healthy subjects in the community of Ile-Ife, SouthWestern Nigeria. Antibiotic susceptibility testing was assessed by the disc diffusion test while antibiotic resistance genes were analysed by PCR. mecA positive isolates were analysed by Staphylococcal Chromosome Cassette mec (SCCmec) and cassette chromosome recombinase (ccr) complex typing methods. Results: Resistance genes were detected only in isolates that showed resistance by phenotypic screening. The aac (6′)-aph(2″) gene was detected in all the three isolates resistant to gentamicin. Four of the five erythromycin resistant isolates were positive for the ermC gene, the remaining isolate carried the msrA gene. The tetK gene was detected in 6 of the 7 tetracycline resistant isolates while 4 possessed the tetM gene. Three of the isolates (S. haemolyticus, S. xylosus and S. capitis) had both genes. Several SCCmec types were found: SCCmec I-ccrABβ2-α2 (4 isolates: 3 S. epidermidis, 1 S. warneri), SCCmecIVb-ccrABβ2-α3 (1 isolate: S. epidermidis), SCCmecIVd-ccrABβ2-α3 (8 isolates: 3 S. epidermidis, 2 S. xylosus, 1 S. saprophyticus, 1 S. warneri, 1 S. capitis), and untypable (2 isolates: S. epidermidis). Conclusion: This genetic background could be a reservoir for interspecies gene transfer among CoNS and S. aureus in the intestinal tract.
Antimicrobial Agents and Chemotherapy, 2009
In staphylococci, methicillin (meticillin) resistance (MR) is mediated by the acquisition of the mecA gene, which is carried on the size and composition variable staphylococcal cassette chromosome mec (SCCmec). MR has been extensively studied in Staphylococcus aureus, but little is known about MR coagulase-negative staphylococci (MR-CoNS). Here, we describe the diversity of SCCmec structures in MR-CoNS from outpatients living in countries with contrasting environments: Algeria, Mali, Moldova, and Cambodia. Their MR-CoNS nasal carriage rates were 29, 17, 11, and 31%, respectively. Ninety-six MR-CoNS strains, comprising 75 (78%) Staphylococcus epidermidis strains, 19 (20%) Staphylococcus haemolyticus strains, 1 (1%) Staphylococcus hominis strain, and 1 (1%) Staphylococcus cohnii strain, were analyzed. Eighteen different SCCmec types were observed, with 28 identified as type IV (29%), 25 as type V (26%), and 1 as type III (1%). Fifteen strains (44%) were untypeable for their SCCmec. Thirty-four percent of MR-CoNS strains contained multiple ccr copies. Type IV and V SCCmec were preferentially associated with S. epidermidis and S. haemolyticus, respectively. MR-CoNS constitute a widespread and highly diversified MR reservoir in the community.