In vitro study to compare sensitivity of amoxicillin+clavulanic acid and cefpodoxime+clavulanic acid among beta-lactamase positive clinical isolates of gram-positive and gram-negative pathogens.

ABSTRACT

The present study was carried out to compare the in vitro sensitivity of cefpodoxime + clavulanic acid and amoxicillin + clavulanic acid against 55 Gram-positive and 123 Gram-negative beta-lactamase positive clinical isolates. Micro-organisms isolated from different clinical specimens were tested for beta-lactamase/ESBL by using nitrocefin disc test and for metallo beta-lactamase by using double disc synergy test. A total of 299 (93 Gram-positive and 206 Gram-negative) clinical isolates were tested for beta-lactamase. Among 93 Gram-positive clinical isolates 25 (78.12%) out of 32 coagulase positive S. aureus, 23 (60.52%) out of 38 coagulase negative S aureus, 7 (63.63%) out of 11 enterococci and 0 (0%) out of 12 Strept pneumoniae were positive for beta-lactamase /ESBL. Notably Strept pneumoniae was found to be beta-lactamase/ESBL negative. Among 206 Gram-negative clinical isolates, 25 (69.44%) out of 36 acinetobacter spp, 20 (41.66%) out of 48 Branhamella catarrhalis, 24 (64.86%) out of 37 E. coli, 7 (46.66%) out of 15 H influenzae and 22 (62.85%) out of 35 proteus were positive for beta-lactamase/ ESBL/metallo beta-lactamase. Positive strains were tested for comparative sensitivity to amoxicillin+ clavulanic acid and cefpodoxime+clavulanic acid by Kirby Bauer disc diffusion method. As regards comparative sensitivity among beta-lactamase/ESBL positive Gram-positive strains, 84% and 92% strains of coagulase positive S aureus, 65.21% and 86.95% strains of coagulase negative S. aureus, 83.33% and 100% strains of Strept pneumoniae and 71.42% and 100% strains of enterococci were found sensitive to amoxicillin +clavulanic acid and cefpodoxime + clavulanic acid respectively. Sensitivity to amoxicillin+ clavulanic acid and cefpodoxime +clavulanic acid among beta lactamase/ESBL positive Gram-negative strains of acinetobacter spp, Branhamella catarrhalis, E. coli, H. influenzae and proteus spp were found to be 20% and 28%, 100% and 100%, 50% and 75%, 71.42% and 100%, 50% and 68.18% respectively. This study demonstrated that cefpodoxime +clavulanic acid combination has more potent in vitro activity in comparison to amoxicillin+ clavulanic acid combination against beta-lactamase producing strains of Gram-positive and Gram-negative bacteria. Given this broad spectrum of activity, cefpodoxime+clavulanic acid appears well suited for use in the treatment of a variety of healthcare-associated infections.