2013 Volume 57 Numberaac.asm.orgFuri et al.TABLE 3 Genotypes and phenotypes of mutants for cationic antibacterial compoundsaParent and mutant strain ATCC 25923 MO060 MO061 MO062 MO072 MO058 MO059 ATCC 6538 MO063 MO064 MO065 MO037 MO038 MO039 MO040 MO041 RN4220 MO069 MO070 MO071 MO066 MO067 MO068 MO042 MO043 MO044 MOaSelective agent AF AF AF EB EB EBMIC (mg/liter) norA mutation Wild variety A94T T91A T126A T126A T126A T126A Wild kind A107G T126A T126A T89G T89G T90G T90G T90G Wild type A107G A107G T126A T126A A107G T126A A130C T126A A130C T126A A130C T126A A130C T126A NOR 1 16 eight 8 8 eight 8 1 8 eight 8 16 16 8 8 eight 1 eight 16 8 16 eight 16 eight 16 16 16 CIP 1 eight four four four 2 4 0.5 four two two 4 four 4 4 four 0.5 4 8 4 4 four four four 4 4 8 EB 16 64 32 128 128 128 128 four 32 32 32 32 256 256 32 16 8 64 64 64 128 64 64 256 256 128 128 AF 32 256 256 256 256 256 256 16 128 128 128 64 256 256 64 256 16 256 256 128 256 256 256 256 256 256 256 CHX two four 4 four 4 4 4 four 4 four four eight 4 four four 4 eight four four four 4 four 4 8 8 four eight BZC two 4 4 four four four 4 2 four four four four four 4 four 4 two 4 4 8 4 four four 4 four 8MBC (mg/liter) NOR 8 16 eight 16 8 eight eight 2 eight 8 eight 16 16 eight 16 eight 2 eight 16 16 16 16 16 16 16 16 16 CIP 1 8 4 4 four 16 four 0.five 4 four 4 four four 4 4 4 1 4 eight 4 eight four 8 eight 8 16 8 EB 16 128 64 128 128 128 128 16 32 64 64 64 256 256 128 64 16 128 128 64 128 128 128 256 256 256 128 AF 64 256 256 256 256 256 256 32 256 256 256 128 256 256 64 256 32 256 256 256 256 256 256 256 256 256 256 CHX two eight 4 32 4 32 4 4 four four eight 128 eight 16 32 64 8 8 8 4 eight 8 32 eight 32 8 8 BZC four 8 4 eight four 16 4 eight four 8 4 4 8 eight 4 four two eight eight 8 eight eight eight four four 8AF AF AF CHX CHX CHX CHX CHXAF AF AF EB EB EB CHX CHX BZC BZCNOR, norfloxacin; CIP, ciprofloxacin; EB, ethidium bromide; AF, acriflavine; CHX, chlorhexidine; BZC, benzalkonium chloride.chlorhexidine (Fig. 1A and E). Within the case with the group of strains with MICs to ethidium bromide of up to 32 mg/liter, qac determinants have been detected only in 12/160 (7.5 ) isolates (ethidium bromidesusceptible strains), though clinical strains with low susceptibility to ethidium bromide possess a strong association together with the presence of qacA and qacB genes (ethidium bromide MIC of 64 mg/liter; P 0.001). The presence of qacA increased the mode MIC for ethidium bromide by 5 dilutions (Fig. 1J). The only qacGcarrying strain showed a MIC value of 64 mg/liter, whilst the MIC values of qacCpositive strains didn’t fall into the group of ethidium bromideresistant strains but have been distributed about an intermediate MIC of 32 mg/liter. The distribution of acriflavine MIC values was related to that of ethidium bromide (data not shown). MLST evaluation. Amongst the 91 clinical isolates analyzed, 84 belonged to 13 previously reported STs, while 7 strains showed a new ST as a consequence of the presence of at the very least a single novel allele or towards the presence of a mixture of alleles previously unreported.1370633-67-2 site Almost all strains carrying qac genes fell into clonal complicated 5, on the list of important lineages of nosocomial MRSA.856562-91-9 Purity The detailed information on MLST are shown in Table S3 inside the supplemental material.PMID:24563649 Mutant selection and phenotype analysis. Mutants of S. aureus ATCC 6538, ATCC 25923, and RN4220 have been chosen on a series of cationic antimicrobial substances, including ethidium bromide, acriflavine, benzalkonium chloride, and chlorhexidine. Singleexposure mutants might be chosen by acriflavine with frequencies of two.1 ten 9 in RN4220, 1.5 10 9 in ATCC 25923,and 5.4 10 9 in ATCC 6538. A equivalent frequency was located by selecting ethidium bromide mutants in ATCC 25923 (two.eight 10 9), though ethidium bromide mutants had a frequency close to the limit of.