Susceptibility Profiles of Enterococcus faecalis to Selected Antibiotics
Abstract
This study was conducted in order to determine the susceptibility of Enterococcus faecalis to the antibiotics penicillin, erythromycin, tetracycline, chloramphenicol and gentamicin through measuring the zone of inhibition. The susceptible, intermediate and resistant categories were assigned on the basis of the critical points recommended by the Clinical and Laboratory Standards Institute. E. faecalis was susceptible to tetracycline as low as 20 μg/20 μl. Starting at a dose of 60 μg/20 μl and 200 μg/20 μl, the bacterium was susceptible to penicillin and erythromycin, respectively. The bacterium was resistant to chloramphenicol even at the highest dosage of 400 μg/20 μl. Meanwhile, from 5 to 100 μg/20 μl, the bacterium was resistant to gentamicin and the classification was changed into intermediate starting at 200 μg/20 μl.
Keywords: Enterococcus faecalis, antibiotics, susceptibility
Downloads
References
2. Gilmore MS, Courvalin DBP, Dunny GM, Murray BE, Rice LB, The Enterococci: Pathogenesis, molecular biology, and antibiotic resistance, ASM Press, Washington, DC, 2002.
3. Sherman JM, The streptococci. Bacteriological Review, 1937; 1:3-97.
4. Hartke A, Giard JC, Laplace JM, Auffray Y, Survival of Enterococcus faecalis in an oligotrophic microcosm: Changes in morphology, development of general stress resistance, and analysis of protein synthesis, Applied Environmental Microbiology, 1998; 64:4238-4245.
5. Franz CMAP, Holzapfel WH, Stiles ME, Enterococci at the crossroads of food safety? International Journal of Food Microbiology, 1999; 47:1-24.
6. Kacmaz B, Aksoy A, Antimicrobial resistance of enterococci in Turkey, International Journal of Antimicrobial Agents, 2005; 25:535-538.
7. Brown DFJ, Brown NM, Cookson BD, Duckworth G, Farrington M, French GL, King L, Lewis D, Livermore DM, National glycopeptide-resistant enterococcal bacteremia surveillance working group report to the Department of Health, Journal of Hospital Infection, 2006; 1:1-27.
8. Peters J, Mac K, Wichmann-Schauer H, Klein G, Ellerbroek L, Species distribution and antibiotic resistance patterns of enterococci isolated from food of animal origin in Germany, International Journal of Food Microbiology, 2003; 88:311-314.
9. Clinical and Laboratory Standards Institute, Performance for antimicrobial disk susceptibility tests: Approved standard, Available at: https://www.google.com.ph/search?ei=yoHBWtzWH4L88QWS2b7oCA&q=Performance+for+antimicrobial+disk+susceptibility+tests%3B+approved+standard.+11th+edition.+CLSI+document+M02A11.+&oq=Performance+for+antimicrobial+disk+susceptibility+tests%3B+approved+standard.+11th+edition.+CLSI+document+M02-A11.+&gs_l=psy-ab.3...241873.244115.0.244688.2.2.0.0.0.0.209.209.2-1.1.0....0...1.1.64.psy-ab..1.0.0....0.0I97lQN3ZOk.
10. Roberts MC, Update on acquired tetracycline resistance genes, FEMS Microbiology Letter, 2005; 245:195-203.
11. Thompson SA, Maani EV, Lindell AH, King CJ, McArthur JV, Novel tetracycline resistance determinant isolated from an environmental strain of Serratia marcescens, Applied Environmental Microbiology, 2007; 73:2199-2206.
12. Fontana R, Aldegheri M, Ligozzi M, Lopez H, Sucari A, Satta G, Overproduction of a low-affinity penicillin-binding protein and high-level ampicillin resistance in Enterococcus faecium, Antimicrobial Agents Chemotherapy, 1994; 38:1980-1983.
13. Madigan M, Martinko J, Bender K, Buckley D, Stahl D, Brock biology of microbiology. 14th edition, 2015.
14. Franz CMAP, Muscholl-Silberhorn AB, Yousif NMK, Vancanneyt M, Swings J, Holzapfel WH, Incidence of virulence factor and antibiotic resistance among enterococci isolated from food, Applied Environmental Microbiology, 2001; 67(9):4385-4389.
15. Forbes BA, Sahm DF, Weissfield AS, Bailey and Scott’s Diagnostic Laboratory, 10th edition. Mosby Inc. St Louis, Missouri, USA, 1998, p 120.
16. Giguere S, Antimicrobial drug action and interaction: An introduction. Antimicrobial Therapy in Veterinary Medicine, 4th edition, Blackwell Publishing, Ames Iowa, USA, 2006.
17. Moellering Jr, RC, Wennersten C, Weinberg AN, Studies on antibiotic synergism against enterococci, I. Bacteriologic studies, Journal of Laboratory Clinical Medicine, 1971; 77:821-828.
18. Ferretti JJ, Gilmore KS, Courvalin P, Nucleotide sequence analysis of the gene specifying the bifunctional 6'-aminoglycoside acetyltransferase 2″-aminoglycoside phosphotransferase enzyme in Streptococcus faecalis and identification and cloning of gene regions specifying the two activities, Journal of Bacteriology, 1986; 167:631-638.
19. FAO, Responsible use of antibiotics in aquaculture, FAO Fisheries Technical Paper, 2005; 469:1-97.
20. Cabello FC, Heavy use of prophylactic antibiotics in aquaculture: a growing problem for human and animal health and for the environment, Environmental Microbiology, 2006; 8:1137-1144.
21. Kuhn I, Iversen A, Burman LG, Olsson-Liljequist B, Franklin A, Finn M, Aarestrup F, Seyfarth AM, Taylor ARH, Caplin J, Moreno MA, Dominguez L, Mollby R, Epidemiology and ecology of enterococci, with special reference to antibiotic resistant strains, in animals, humans and the environment. Example of an ongoing project within the European research programme, International Journal of Antimicrobial Agents, 2000; 14:337-342.

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Authors who publish with this journal agree to the following terms:
- Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License. that allows others to share the work with an acknowledgment of the work's authorship and initial publication in this journal.
- Authors are able to enter into separate, additional contractual arrangements for the non-exclusive distribution of the journal's published version of the work (e.g., post it to an institutional repository or publish it in a book), with an acknowledgment of its initial publication in this journal.
- Authors are permitted and encouraged to post their work online (e.g., in institutional repositories or on their website) prior to and during the submission process, as it can lead to productive exchanges, as well as earlier and greater citation of published work (See The Effect of Open Access).