COMPARISON OF ANTIBIOTIC SUSCEPTIBILITY TEST ON NUTRIENT AGAR AND MUELLER HINTON’S AGAR

Abstract

Background: Antibiotic resistance is caused by overuse and misuse of antimicrobial agents and is found out by an antibiotic susceptibility test (AST). For that, Mueller Hinton agar (MHA) is the recommended medium, however, when unavailable, nutrient agar can also be used.

Objective: To compare the efficiency of nutrient agar and Mueller Hinton’s agar in determining the zones of inhibition during antibiotic susceptibility test.

Material and Methods: This descriptive study was carried out in 2 months at Khyber Medical University (IPDM, KMU), Peshawar. 10 preserved samples of Streptococcus mutants isolates were cultured by Kirby Bauer method, using nutrient agar and MHA. Antibiotic discs containing amoxicillin, doxycycline, and clindamycin were applied. Post incubation, zones of inhibition (ZOI) of all drugs were checked and compared for nutrient agar and MHA. The results were analyzed using IBMS SPSS, version 22.

Results: Paired T test was performed that showed the mean ZOI for amoxicillin on nutrient agar and MHA as 14.06 and 13.89, respectively. (T value= 1.4, P value =0.19) For doxycycline, ZOI on nutrient agar and MHA were 17.78 and 17.89, respectively. (T value= -1, P value= 0.34). Whereas, clindamycin had mean ZOI on nutrient agar and MHA as 14.50 and 14.56. (T value= -1, P value= 0.35).

Conclusion: Paired T test was performed that showed the mean ZOI for amoxicillin on nutrient agar and MHA as 14.06 and 13.89, respectively. (T value= 1.4, P value =0.19) For doxycycline, ZOI on nutrient agar and MHA were 17.78 and 17.89, respectively. (T value= -1, P value= 0.34). Whereas, clindamycin had mean ZOI on nutrient agar and MHA as 14.50 and 14.56. (T value= -1, P value= 0.35)