016 474 AAC → AAT –         498 GCG → GCT –         502 GTA → GTG –         518 ACA → ACG – ST5- MRSA-I (5) C (1)/t045 (1) Cape Town, RSA ≥ 256 481 CAT → TAT H481Y         498 GCG → GCT –         630 AAT → AAC –         658 GGT → GGA – ST612- MRSA-IV (8) {Selleck Anti-infection Compound Library|Selleck Antiinfection Compound Library|Selleck Anti-infection Compound Library|Selleck Antiinfection Compound Library|Selleckchem Anti-infection Compound Library|Selleckchem Antiinfection Compound Library|Selleckchem Anti-infection Compound Library|Selleckchem Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|Anti-infection Compound Library|Antiinfection Compound Library|buy Anti-infection Compound Library|Anti-infection Compound Library ic50|Anti-infection Compound Library price|Anti-infection Compound Library cost|Anti-infection Compound Library solubility dmso|Anti-infection Compound Library purchase|Anti-infection Compound Library manufacturer|Anti-infection Compound Library research buy|Anti-infection Compound Library order|Anti-infection Compound Library mouse|Anti-infection Compound Library chemical structure|Anti-infection Compound Library mw|Anti-infection Compound Library molecular weight|Anti-infection Compound Library datasheet|Anti-infection Compound Library supplier|Anti-infection Compound Library in vitro|Anti-infection Compound Library cell line|Anti-infection Compound Library concentration|Anti-infection Compound Library nmr|Anti-infection Compound Library in vivo|Anti-infection Compound Library clinical trial|Anti-infection Compound Library cell assay|Anti-infection Compound Library screening|Anti-infection Compound Library high throughput|buy Antiinfection Compound Library|Antiinfection Compound Library ic50|Antiinfection Compound Library price|Antiinfection Compound Library cost|Antiinfection Compound Library solubility dmso|Antiinfection Compound Library purchase|Antiinfection Compound Library manufacturer|Antiinfection Compound Library research buy|Antiinfection Compound Library order|Antiinfection Compound Library chemical structure|Antiinfection Compound Library datasheet|Antiinfection Compound Library supplier|Antiinfection Compound Library in vitro|Antiinfection Compound Library cell line|Antiinfection Compound Library concentration|Antiinfection Compound Library clinical trial|Antiinfection Compound Library cell assay|Antiinfection Compound Library screening|Antiinfection Compound Library high throughput|Anti-infection Compound high throughput screening| D (2), E (5), sporadic isolates (2)/t064 (3), t1443 (5), t1257 (1) Cape Town, RSA ≥ 256 481 CAT → AAT H481N         498 GCG → GCT –         512 CGT → CGC –         527 ATT → ATG I527M ST612- MRSA-IV (8) ND6 (2)/t064

(2) RSA (N83; N84) ≥ 256 481 CAT → AAT H481N         498 GCG → GCT –         512 CGT → CGC –         527 ATT → ATG I527M ST612- MRSA-IV (8) ND (1)/t064 (1) Australia (04-17052) ≥ 256 481 CAT → AAT H481N         498 GCG → GCT –         512 CGT → CGC –         527 ATT → ATG I527M ST612- MRSA-IV (8) ND (1)/t7571 (1) Australia (09-15534) ≥ 256 481 CAT → AAT H481N         498

GCG → GCT –         512 CGT → CGC –         527 ATT→ATG I527M         579 AAA→AGA K579R 1 Clonal types are indicated using the current international nomenclature (sequence type (ST) – antimicrobial phenotype – staphylococcal cassette chromosome mec (SCCmec) type) 2 PFGE, pulsed-field gel electrophoresis 3 As determined by E-test 4 S. aureus co-ordinates 5 RSA, Republic of South Africa 6 ND, not determined In addition to the mutations associated with amino acid substitutions in RpoB, silent single nucleotide polymorphisms (SNPs) were detected in the rpoB sequences of all 16 isolates (Table 2). Based on a comparison with the corresponding sequence NVP-BSK805 manufacturer of the rifampicin-susceptible S. aureus strain RN4220, all isolates shared a common SNP at amino acid 498 (GCG → GCT), as shown in Table 2. Otherwise between one and three additional SNPs particular to each clonal type were identified. Of note is the conserved SNP at amino acid 512 (CGT → CGC), which was detected in TCL all 13 ST612-MRSA-IV isolates (Table 2). Discussion A number

of factors drive the emergence and spread of antibiotic resistance, including antibiotic usage, infection control practices and the organism’s genetics [1]. Previous studies carried out in South Africa have reported large proportions of rifampicin-resistant MRSA isolates [2–5], and this study is no exception with the prevalence of rifampicin-resistance among MRSA isolates ranging from 39.7% to 46.4% (Figure 1). It is likely that the frequent use of rifampicin to treat see more tuberculosis in South Africa has driven the high prevalence of rifampicin-resistance among local MRSA. Support for this suggestion comes from the work of Sekiguchi et al. [14] who reported a significantly higher prevalence of rifampicin-resistant MRSA in tuberculosis wards compared to non-tuberculosis wards in two hospitals in Japan. A previous study showed that ST612-MRSA-IV was the dominant clone circulating in public hospitals in Cape Town. The 44 isolates corresponding to this clonal type were uniformly resistant to rifampicin.