Science Letters

Antibiotic sensitivity of different fluoroquinolones and aminoglycosides against milk and beef bacterial isolates

Farzana Khatoon 1, Anum Fatima 1, Khawar Ali Shahzad 1*, Farzana Iftikhar 2, Kashif Siddique 3, Muhammad Qasim 4, Muhammad Younis 5, Muhammad Shoaib Butt 6, Mahmood Ul Hassan Qazi 1

1 Institute of Molecular Biology and Biotechnology, The University of Lahore, Lahore, Pakistan.

2 Department of Microbiology and Molecular Genetics, The women University of Multan, Multan, Pakistan.

3 Biostatistician, Mayo Hospital, Lahore, Pakistan.

4 Department of Microbiology, University of Veterinary and Animal Sciences, Lahore, Pakistan.

5 Institute of Biochemistry, University of Sindh, Jamshoro, Pakistan.

6 Department of Material Science, Southeast University, Nanjing, China.

Abstract

Food is essential to mankind, but it becomes harmful for human beings when it is contaminated with food-borne pathogens. Antibiotics are used indiscriminately in controlling food-borne infections. A research was conducted to find out suitable antibiotics for treating food-borne infections. In this study, 200 samples of un-processed milk and raw beef (100 each) were collected from different outlets of Lahore, Pakistan. Milk and beef samples 75% and 85%, respectively, were positive for total viable count having 30-300 colonies per milliliter of milk and beef wash. Five major food-borne pathogens were isolated. The isolated bacterial species were purified and confirmed by different biochemical tests. It included both Gram positive (Staphylococcus aureus and Bacillus cereus) and Gram negative (Escherichia coli, Salmonella typhi and Campylobacter jejuni) bacterial strains. Antibiotic sensitivity test was applied on the isolated and purified bacterial strains with ten selected broad spectrum aminoglycoside antibiotics (amikacin, gentamycin, neomycin, streptomycin and tobramycin) and fluoroquinolone antibiotics (ciprofloxacin, levofloxacin, moxifloxacin, flumequine and pefloxacin). After 24 hrs of incubation of commercially prepared antibiotic discs on Mueller-Hinton agar plates, gram-positive cocci showed highest sensitivity to selected salts of fluoroquinolone and aminoglycoside antibiotics, while gram-negative rods were least sensitive to fluoroquinolone salts. It was concluded that among the fluoroquinolones, moxifloxacin was highly effective against Bacillus cereus whereas among aminoglycosides, gentamycin was the best choice of drug in therapeutics of food-borne diseases.

Keywords: Antibiotic sensitivity testing, food-borne diseases, antibiotics, infection.

Received December 12, 2013; Revised February 21, 2014; Accepted February 27, 2014

*Corresponding Author: Khawar Ali Shahzad; Email: khawar7bar@yahoo.com;