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In vitro Study on the Antimicrobial Activity of Human Tears with Respect to Age
Korean J Clin Lab Sci 2018;50:93-99  
Published on June 30, 2018
Copyright © 2018 Korean Society for Clinical Laboratory Science.

Muhammad Zahoor1, Haji Bahadar2,3, Muhammad Ayaz1, Ajmal Khan4, Muhammad Jalat Shah2

1Department of Chemistry, University of Malakand Chakdara Dir (lower), Khyber Pakhtunkhwa, Pakistan
2Institute of Basic Medical Sciences, Khyber Medical University, Peshawar, Pakistan
3Institute of Paramedical Sciences, Khyber Medical University, Peshawar, Pakistan
4Department of Chemistry, COMSATS Institute of Information Technology, Abbottabad, Pakistan
Correspondence to: Haji Bahadar
Institute of Paramedical Sciences, Khyber Medical University, Peshawar 25100, Pakistan Tel: +92-91-9217703, 9217696 Fax: +92-91-9217704 E-mail:
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Lysozyme is present in tears and has the ability to inhibit bacterial growth. In addition, it acts as a physiological scavenger for harmful substances. In the present study, sixteen tear samples from people of different ages were evaluated for their antibacterial spectrum against selected bacterial strains (Escherichia coli, Shigella sonnei, Staphylococcus aureus, Salmonella enterica Typhi). A radial diffusion assay was used to evaluate the antibacterial potential of tear samples. To correlate the antibacterial activities of these tear samples, the concentration of lysozyme in the tear samples was also determined. Ampicillin was used as a standard drug. The zone of inhibition (mm) was used to measure the antibacterial property of the tears. All samples showed good antibacterial activities. The tear samples of children showed antibacterial activities in the range of 4.40∼5.00 mm inhibition zones against the selected bacterial strains. The tear samples from the young and adults showed good antibacterial potential with a zone of inhibition in the range of 3.20∼4.00 and 4.00∼5.50 mm, respectively. The tear samples from the old age group showed inhibition zones from 1.50∼5 mm. The adult tear samples showed the maximum inhibition against the selected bacterial strains among all groups. The lysozyme concentration was 1.7 mg/mL, 1.95 mg/mL, 2.13 mg/mL, and 1.76 mg/mL for children, young, adults, and elderly, respectively. In conclusion, the tears from adults have the high inhibition potential. In addition, this data also showed that the lysozyme contents in the tear sample increased with age until 40∼42 years.
Keywords : Ampicillin, Antibacterial activities, Lysozyme, Tear samples

June 2018, 50 (2)
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