Sr. Deshmukh et al., NORFLOXACIN INDUCED RESISTANCE TO FLUOROQUINOLONES AND STRUCTURALLY UNRELATED ANTIMICROBIAL AGENTS IN COAGULASE-NEGATIVE STAPHYLOCOCCI, INDIAN JOURNAL OF MEDICAL RESEARCH, 106, 1997, pp. 461-464
Nine clinical isolates of coagulase negative staphylococci(CONS) susce
ptible to norfloxacin (MIC 1.8-2 mu g/ml) were manipulated in vitro to
induce norfloxacin resistance by means; of serial passage in brain he
art infusion broth containing increasing concentrations of norfloxacin
. Exposure of CONS to norfloxacin resulted in 18 to 20 times increase
in MIC of norfloxacin and change in in vitro susceptibility to ciprofl
oxacin pefloxacin, ofloxacin, kanamycin, neomycin and tobramycin, indi
cating development of cross resistance to fluoroquinolones and aminogl
ycosides. These results show that exposure to increasing concentration
s of norfloxacin can induce the development of resistance to various a
ntimicrobial agents, suggesting its mutagenic role.