Diversity of staphylococcal cassette chromosome mec structures in coagulase-negative staphylococci and relationship to drug resistance

Abstract

The objective of this study was to determine the distribution of staphylococcal cassette chromosome mec (SCCmec) elements in meticillin-resistant coagulase-negative staphylococci (MR-CoNS) isolated from a tertiary-care hospital in Mexico and to examine the relationship to drug resistance. Fifty selected MR-CoNS isolates collected from catheters (n515), blood (n515), bone (n59), bronchial lavage (n52) and urine (n52) and one isolate each from an abscess, cerebrospinal fluid, eye, pleural effusion, synovial fluid, tracheal aspirate and wound secretion were examined. Susceptibility testing was performed by the broth microdilution method. SCCmec types were determined by multiplex PCR and PFGE was carried out as described previously for Staphylococcus aureus. Among the MR-CoNS strains studied, the most frequently isolated species were Staphylococcus epidermidis (n526) and Staphylococcus haemolyticus (n513). Staphylococcus cohnii (n55), Staphylococcus hominis (n53), Staphylococcus sciuri (n51), Staphylococcus pasteuri (n51) and the recently described species Staphylococcus pettenkoferi (n51) were also identified. The most frequent MR-CoNS genotype identified was SCCmec type IVa in S. epidermidis isolates, which also showed a high diversity in their PFGE patterns. A clone was found that amplified both SCCmec III and V elements in five isolates examined. The single MR S. pettenkoferi isolate harboured SCCmec type IVd and the single MR S. pasteuri isolate harboured SCCmec type I. The carriage of SCCmec type III was associated with resistance or intermediate resistance to meropenem (P ,0.05). These results confirm the high prevalence of S. epidermidis SCCmec IVa and the high genetic diversity among MR-CoNS strains. As far as is known, this is the first report describing the newly identified S. pettenkoferi possessing SCCmec IVd and S. pasteuri harbouring SCCmec type I. MR-CoNS harbouring SCCmec type III were found to be more resistant to meropenem.

Analysis of Antibiotic Resistance Genes and its Associated SCC mec Types among Nasal Carriage of Methicillin Resistant Coagulase Negative Staphylococci from Community Settings, Chennai, Southern India

“…The impact of antibiotic selective pressure might possibly explain the high prevalence of MR-CoNS carriage. Among the MR-CoNS isolates, S. epidermidis (n= 20/50, 40%) was the predominant species followed by S. haemolyticus (n= 14/50, 28%), S. hominis (n= 10/50, 20%) and S. warneri (n= 6/50, 12%) which was consistent with previous reports [2,17].…”

Staphylococcal cassette chromosome mec typing and mecA sequencing in methicillin-resistant staphylococci from Algeria: a highly diversified element with new mutations in mecA

“…SCCmec IV was predominant in our MRSA strains, a common observation within MR staphylococci isolates in most studies (Ruppe et al, 2009;Garza-Gonzalez et al, 2010;AlBakri et al, 2013;Djoudi et al, 2014). The two MR S. saprophyticus isolates carried SCCmec IVa; however, Söderquist & Berglund (2009) reported that, in this species, SCCmec III was predominant.…”

“…This is a rare finding but previously reported in two isolates of MR S. epidermidis and Staphylococcus hominis (Ruppe et al, 2009). However, 19 of 35 isolates were untypeable, a common observation within MRS, underlying the high degree of variability in genetic background of this genus and the great capacity of generating new SCCmec types (Ruppe et al, 2009;Garza-Gonzalez et al, 2010;Urushibara et al, 2011;Al-Bakri et al, 2013). Such findings underline the importance of studying prevalence and composition of SCCmec in MRS, in order to understand and predict the evolution of methicillin (Mongkolrattanothai et al, 2004;Hanssen & Sollid, 2006).…”

“…In our study, SCCmec III was identified in three isolates of MR S. sciuri, according to literature (Machado et al, 2007;Söderquist & Berglund, 2009). SCCmec IVa was recently described as the most prevalent type among MR S. epidermidis in clinical and nasal carriage isolates (Garza-Gonzalez et al, 2010;Al-Bakri et al, 2013). SCCmec type VII, with mec complex type C1 and ccr complex type C1, was identified in four MR S. haemolyticus and three MRSA isolates.…”

Comparative Epidemiology of Staphylococcus epidermidis Isolates from Patients with Catheter-Related Bacteremia and from Healthy Volunteers

“…One of these STs, ST2, was recognized as representing the majority of methicillin-resistant S. epidermidis (MRSE) clinical strains (9,10). ST2 isolates usually harbor the ica operon (11) and can carry different SCCmec types (12).…”