Diversity of SCCmec Elements in Methicillin-Resistant Coagulase-Negative Staphylococci Clinical Isolates

Abstract

BackgroundMethicillin-resistant coagulase-negative staphylococci (MR-CoNS) are opportunistic pathogens and serve as a large reservoir of staphylococcal cassette chromosome mec (SCCmec). Characterization of SCCmec in MR-CoNS can generate useful information on the mobilization and evolution of this element.Methodology/Principal FindingsNon-repetitive MR-CoNS clinical isolates (n = 84; 39 S. epidermidis, 19 S. haemolyticus, 9 S. hominis, 6 S. capitis, 4 S. warneri, 2 S. cohnii, 2 S. saprophyticus, 1 S. kloosii, 1 S. simulans and 1 S. massiliensis) were collected. All isolates could grow on plates with 4 mg/L cefoxitin and all had mecA as detected by PCR. Strain typing using RAPD and ERIC-PCR revealed that almost all isolates were of different strains. SCCmec typing was performed using multiplex PCR published previously. For isolates in which SCCmec could not be typed, the mec complex classes were determined by additional PCR and the ccr genes were amplified with published or newly-designed primers and then sequenced. SCCmec types were assigned for 63 isolates by multiplex PCR and were assigned for 14 other isolates by PCR targeting mec and ccr. Among 77 isolates with determined SCCmec types, 54 had a single type, including type III (n = 19), IV (n = 14), V (n = 10), II (n = 2), I (n = 1), VIII (n = 1) and five unnamed types (n = 7), while 23 isolates had two types, III+V (n = 12), II+V (n = 8), II+IV (n = 2) or IV+V (n = 1). The five unnamed types were assigned UT1 (class A mec, ccrA1/ccrB4), UT2 (class C1 mec, ccrA4/ccrB4), UT3 (class A mec, ccrA5/ccrB3), UT4 (class C2 mec, ccrA2/ccrB2 plus ccrC1) and UT5 (class A mec, ccrA1/ccrB1 plus ccrC1).Conclusions/SignificanceSCCmec types III, IV and V were prevalent in MR-CoNS and many isolates could harbor more than one type. Several new types of SCCmec were identified, highlighting the great genetic diversity and the need of developing classification schemes for SCCmec in MR-CoNS.

Staphylococcus haemolyticus – an emerging threat in the twilight of the antibiotics age

“…These cassettes are mobile genetic elements which might be horizontally transferred. (Młynarczyk & Młynarczyk, 2008;Zong et al, 2011). SCCmec cassettes are localized in the genomic bacterial DNA, at the 39 end of the orfX gene encoding ribosomal methyltransferase.…”

Prevalencia de estafilococos resistentes a meticilina en el personal trabajador del Hospital Clínico Veterinario de la UEX

“…Por otro lado, el gen mecA se ha encontrado en especies coagulasa negativo no responsable de procesos patógenos en los que presumiblemente no debería haberse utilizado una terapia antibiótica, y pueden actuar como reservorio de la resistencia a largo plazo (Nascimento et al, 2015;Zong et al, 2011).…”

Surveillance of bacteria Pseudomonas aeruginosa and MRSA associated with acute suppurative otitis media (ASOM)

“…The remarkable ability of S. aureus and CONS to acquire antibiotic resistance limits therapeutic options, attended with high rates of morbidity and mortality, including costs of hospitalization. 19 Particularly, several clonal variants of S. aureus and MRSA are resistant to the penicillin group of antibiotics, methicillin/oxacillin. Moreover, in a German study, it was reported that a majority of MRSA strains were from wound infections (56.9%), with pneumonia cases being A B…”