Antibacterial Activity of Lemongrass (Cymbopogon citratus) on Streptococcus pyogenes and Staphylococcus aureus Isolated from Throat of University Students

Abstract

Asymptomatic throat infections are on the increase among University students and has led to a public health problem, as pathogens can be transmitted from one person to another. The present study aims to determine the antibacterial activity of lemon grass (Cymbopogon citratus) against Streptococcus pyogenes and Staphylococcus aureus isolated from throat of University students. Samples of throat swabs were collected from thirty-three (33) students who were not showing any symptoms of illness at the time of collection. The bacterial species were isolated and characterized using standard microbiological methods. Ethanolic and methanolic leaf extracts of lemongrass were tested against the isolates. Out of the thirty-three throat swab samples screened, Streptococcus pyogenes was identified in 14(42.42%), including 8(47.1%) males and 6(37.6%) female samples. Staphylococcus aureus was detected in 12(36.36%), 5(29.4%) males and 7(43.75%) females. There was no significant difference (p˃0.05) between the carriage rate of males and females. The inhibition zone diameter (IZD) of ethanolic and methanolic leaf extracts of lemongrass ranged from 6 mm – 25 mm and 4 mm- 22 mm respectively on the isolates. The minimum inhibitory concentrations (MIC) of the ethanolic and methanolic leaf extracts were 6.125 mg/ml and12.5 mg/ml respectively. Antibiotic susceptibility profiles revealed that Streptococcus pyogenes 6(42.9%) and Staphylococcus aureus 11(42.3%) were resistant and Streptococcus pyogenes 8 (57.1%) and Staphylococcus aureus 7 (58.3%) were sensitive to Azithromycin used as standard antibiotic. The phytochemical analyses revealed the presence of saponins, tannins, flavonoids, terpenoids, steroids, oils and glycosides. In conclusion, lemongrass exhibited immense inhibitory action on the bacterial species. Thus, can be an alternative to antibiotics to reduce the multiplication and colonization of bacteria in the human throat.