Sub-inhibitory concentrations of some antibiotics can drive diversification of Pseudomonas aeruginosa populations in artificial sputum medium

Table 1 Number of isolates in each group (total of 120) exhibiting each of the traits measured

	Colony morphology		Virulence	Mutations	Outside normal range of antimicrobials susceptibility
Culture	Green non-mucoid	Straw non-mucoid	Pyocyanin	Hypermutability	Ceftazidime	Ciprofloxacin	Tobramycin	Meropenem	Colistin	Tazobactam/piperacillin
ASM	120	0	117	0	3	0	19	0	2	8
ASM + CAZ	110	10	92	0	16	19	20	18	10	11
ASM + CT	113	7	84	0	17	37	29	15	7	9
ASM + AZT	120	0	120	0	0	16	34	0	4	4
ASM + MEM	120	0	118	0	1	8	4	0	0	1
ASM + TOBI	118	2	119	0	1	24	69	3	22	1
LB (18 hours)	120	0	120	1	0	0	0	0	0	0

Isolates that were characterized as being outside the normal range of antimicrobial susceptibility typically observed in LESB58, included isolates that had either an increased or reduced susceptibility to the antibiotic under test. ASM = Artificial Sputum Medium, LB = Luria Bertani, CAZ = Ceftazidime, CT = Colistin, AZT = Azithromycin, MEM = Meropenem and TOBI = Tobramycin.

ISSN: 1471-2180