Distribution of staphylococcal cassette chromosome mec (SCCmec) types I, II, III and IV in coagulase-negative staphylococci from patients attending a tertiary hospital in southern Brazil

Abstract

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 4 (3.0 %) harboured SCCmec types I and III. Seventeen isolates were not typable. Identification of CoNS at the species level indicated that Staphylococcus epidermidis was the most common species, with 87 isolates, followed by Staphylococcus haemolyticus (15), Staphylococcus hominis (13), Staphylococcus capitis (12) and Staphylococcus sciuri (1). SCCmec type III was the most prevalent among isolates of S. epidermidis (52 %). Among these strains, 30 (23 %) harboured a modified SCCmec type III which contained an additional dcs region in comparison with regular type III. SCCmec type III was also highly prevalent (75 %) among S. capitis isolates. The predominant SCCmec type found among S. haemolyticus isolates was type I. However, all four isolates harbouring SCCmec type II belonged to S. haemolyticus. Our results indicate that SCCmec type III was the most prevalent among the CoNS. Isolates with SCCmec type III were more resistant to non-b-lactam antimicrobials than isolates harbouring SCCmec types I, II and IV, although the increase in resistance was statistically significant only for clindamycin (P50.021), rifampicin (P50.010) and levofloxacin (P50.005).

Genetic determinants and biofilm formation of clinicalStaphylococcus epidermidisisolates from blood cultures and indwelling devises

“…The SCCmec non-typeable isolates shared the resistance profi le against clindamycin and erythromycin, in contrast to SCCmec type III isolates with low resistance rates toward both antibiotics. The results for SCCmec types I and III were supported by those of Mombach Pinheiro Machado et al [44], although they detected for both types higher resistance rates against gentamicin and trimethoprim-sulfamethoxazole and for SCCmec type I lower resistance rates toward clindamycin and erythromycin. For SCCmec type III isolates, Mombach Pinheiro Machado et al [44] described much higher resistance rates toward clindamycin and erythromycin.…”

“…The results for SCCmec types I and III were supported by those of Mombach Pinheiro Machado et al [44], although they detected for both types higher resistance rates against gentamicin and trimethoprim-sulfamethoxazole and for SCCmec type I lower resistance rates toward clindamycin and erythromycin. For SCCmec type III isolates, Mombach Pinheiro Machado et al [44] described much higher resistance rates toward clindamycin and erythromycin. The divergent rates may be refl ected by the geographical location of the study population, administration, and consumption of different antibiotics.…”

“…Mombach Pinheiro Machado et al [44] studied 129 methicillin-resistant coagulase-negative staphylococci isolated from blood cultures and determined SCCmec type I as most prevalent in S. epidermidis; similar to our study, SCCmec IV was infrequent, and very few isolates were non-typeable. The difference in distribution of the SCCmec between our study and that of Mombach Pinheiro Ma chado et al [44] in Brazil was the number of SCCmec types II and III. They had no SCCmec type II in their population.…”

Epidemiological Aspects of Oxacillin-Resistant Staphylococcus spp.: The Use of Molecular Tools with Emphasis on MLST

“…This element varies in its constitution and is divided into eleven types. The typing of SCCmec types is useful as an epidemiological tool (Mombach Pinheiro Machado et al, 2007) given that the different types are more prevalent in hospital and community environments. The SCCmec types (IWG-SCC, 2009) differ from one another in relation to the number of genes that they carry in their gene architecture (Hiramatsu et al, 2001).…”

Reliability of the BD GeneOhm Methicillin-Resistant Staphylococcus aureus (MRSA) Assay in Detecting MRSA Isolates with a Variety of Genotypes from the United States and Taiwan

“…The primers and probes of the BD GeneOhm MRSA assay detect a proprietary sequence in the orfX gene adjacent to the SCCmec integration site and the SCCmec terminus, as described previously (13). Since coagulase-negative staphylococcus species are often methicillin resistant and also carry SCCmec (12,15,19), the species-specific primer in orfX ensures that the assay will not mistake methicillin-resistant coagulase-negative Staphylococcus species for MRSA. SCCmec elements are characterized by the mec class and ccr recombinase complex responsible for integration and excision of the element.…”