The Influence of L-Ascorbic Acid on the Possible Repression of B-Lactamase Synthesis and Function Studied in Ampicillin-Induced Resistance of Haemophilus influenzae

Abstract

An induced B-lactamase mediated resistance was investigated in meningitis-causing Haemophilus influenzae. The organism was isolated from three different patients with purulent ear discharge making three isolates. It was found out hat the best medium (considering the availability) for growing the fastidious organism was the cation-supplemented Mueller-Hinton Agar. A purified isolates were then induced to synthesize the B-lactamase by subjecting them into the antibiotic. The B-lactamase producing strains were then subjected to broth microdilution technique testing for the determination of minimum inhibitory concentration (MIC) of ampicillin trihydrate for each isolated at four levels of L-ascorbic acid namely: 0.25, 1.0, 4.0, 10.0 ug/ml and a control setup. These were then subjected to primary and secondary subjection to simulate in vivo induction. It was found that as the concentration of L-ascorbic acid is increased, the susceptibility level of Haemophilus influenzae to ampicillin trihydrate increases, and vice versa. Applying statistical analysis, particularly analysis of variance and hypothesis testing for the difference of two population means: paired observation showed a significant difference on the effects of different levels of L-ascorbic acid and more so, a significant difference on the different levels of subjection. From primary to secondary subjection, there is a general decrease in susceptibility for all levels. However, the 10 ug/ml showed no significant difference between the primary and secondary. After the MIC determination, another test for B-lactamase synthesis was performed and it was found out that minimal amounts of the enzyme was synthesized. This study leads to the final recommendations that the public is informed not to use less than the recommended dosages and if resistant forms of Haemophilus influenzae is rampant the combination use of L-ascorbic acid and ampicillin trihydrate is hereby recommended to maximize susceptibility.