Assessment of the potential for resistance to antimicrobial violet-blue light in Staphylococcus aureus

Table 2 Antibiotic susceptibility of MSSA and MRSA following sub-lethal exposure to 405 nm light

Antibiotic	Conc (μg)	Mean Diameter of Zone of Inhibition of MSSA (mm)				Mean Diameter of Zone of Inhibition of MRSA (mm)
Antibiotic	Conc (μg)	0	5	10	15	0	5	10	15
Chloramphenicol	25^a	21 ± 1.5	21 ± 0.8	21 ± 1.2	21 ± 0.8	24 ± 1.0	24 ± 1.1	23 ± 1.4	23 ± 1.1
Ciprofloxacin	5	22 ± 1.2	21 ± 0.5	22 ± 0.7	22 ± 1.3	26 ± 0.6	26 ± 0.4	26 ± 1.0	26 ± 1.1
Erythromycin	5^a	21 ± 0.6	21 ± 0.6	22 ± 0.8	21 ± 0.4	23 ± 1.0	22 ± 0.8	23 ± 1.0	23 ± 1.2
Fusidic Acid	10	30 ± 0.0	30 ± 0.8	32 ± 1.0*	31 ± 1.8	31 ± 0.6	30 ± 0.5	30 ± 0.7	30 ± 0.9
Gentamicin	10	21 ± 0.6	21 ± 0.5	21 ± 0.5	20 ± 0.5	21 ± 0.6	21 ± 0.5	22 ± 1.3	23 ± 0.6*
Mupirocin	5^a	28 ± 0.6	26 ± 0.5*	28 ± 1.4	28 ± 1.1	26 ± 0.6	27 ± 1.1	26 ± 1.2	26 ± 1.3
Oxacillin	5^b	30 ± 0.0	29 ± 0.9	30 ± 0.6	30 ± 0.9	0 ± 0.0	0 ± 0.0	0 ± 0.0	0 ± 0.0
Rifampicin	5	32 ± 1.0	32 ± 0.7	33 ± 1.8	34 ± 0.6*	31 ± 0.6	30 ± 0.7	31 ± 1.0	31 ± 0.9
Tetracycline	25^a	28 ± 1.2	28 ± 1.0	28 ± 1.4	29 ± 1.3	27 ± 1.0	27 ± 0.7	27 ± 1.0	26 ± 0.9
Vancomycin	5^b	15 ± 0.0	14 ± 0.7	15 ± 0.7	15 ± 0.5	14 ± 0.6	15 ± 0.6	15 ± 0.5	14 ± 0.5

Antibiotic susceptibility of methicillin-sensitive Staphylococcus aureus (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) after 5, 10 and 15 sub-lethal exposures compared to equivalent non-sub-lethally exposed controls (0). Susceptibility was measured using Disc Diffusion Method
*indicates diameters of zones of inhibition that was significantly different to the equivalent non-sub-lethally exposed control (P ≤ 0.05). Each data point is a mean value ± SD (n ≥ 3)
^aDisc concentration is lower than that recommended by EUCAST
^bNo disc concentration recommended by EUCAST

ISSN: 2047-2994