In vitro antibacterial susceptibility of different brands of oral levofloxacin 250 mg tablet against Staphylococcus aureus and Escherichia coli.

Antibiotics are not only used in morbidity but also help in prevention of infection. The irrational use of broad spectrum antibiotics is now increasing the resistance against pathogens. This present study has been carried out to evaluate the in-vitro antibacterial effect of levofloxacin against clinical isolates. According to Clinical and Laboratory Standards Institute (CLSI) guidelines, minimum inhibitory concentrations 90% (MIC90) of the levofloxacin tested were evaluated by an agar dilution method. Total 63 clinical isolates Staphylococcus aureus (n=34) and Escherichia coli (n=29) were collected from different hospitals at Karachi and were evaluated MIC90 of eleven different brands of levofloxacin tablet (250 mg). Levofloxacin (Reference) was tested against E.coli standard (American Type Culture Collection) (ATCC=25922) with (MIC90; 0.03μg/ml) and compared with different eleven brands of levofloxacin tablets 250mg (MIC90; 0.5μg/ml -16.0μg/ml). Levofloxacin (Reference) sensitivity against S. aureus standard (ATCC=25923) is (MIC90; 0.12μg/ml) and similarly when it was compared with same levofloxacin tablets (MIC90; 0.5-16.0μg/ml). It has been concluded by the present study, a large number of strains of bacteria have shown better bactericidal action of different brands of levofloxacin and nearly all commercialized drugs were appropriate for therapeutic use.