Study of antagonistic effects of Lactobacillus strains as probiotics on multi drug resistant (MDR) bacteria isolated from urinary tract infections (UTIs)

Document Type : Original Article


1 Division of Microbiology, Department of Biology, Faculty of Sciences, Alzahra University, Tehran, Iran

2 Applied Microbiology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran

3 Department of Pharmaceutical Biotechnology, Pasture Institute, Tehran, Iran

4 Department of Bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran


Objective(s):Urinary tract infection (UTI) caused by bacteria is one of the most frequent infections in human population. Inappropriate use of antibiotics, often leads to appearance of drug resistance in bacteria. However, use of probiotic bacteria has been suggested as a partial replacement. This study was aimed to assess the antagonistic effects of Lactobacillus standard strains against bacteria isolated from UTI infections.
Materials and Methods: Among 600 samples; those with ≥10,000 cfu/ml were selected as UTI positive samples. Enterococcus sp., Klebsiella pneumoniae, Enterobacter sp., and Escherichia coli were found the most prevalent UTI causative agents. All isolates were screened for multi drug resistance and subjected to the antimicrobial effects of three Lactobacillus strains by using microplate technique and the MICs amounts were determined. In order to verify the origin of antibiotic resistance of isolates, plasmid curing using ethidium bromide and acridine orange was carried out.
Results: No antagonistic activity in Lactobacilli suspension was detected against test on Enterococcus and Enterobacter strains and K. pneumoniae, which were resistant to most antibiotics. However, an inhibitory effect was observed for E. coli which were resistant to 8-9 antibiotics. In addition, L. casei was determined to be the most effective probiotic. Results from replica plating suggested one of the plasmids could be related to the gene responsible for ampicillin resistance.
Conclusion: Treatment of E. coli with probiotic suspension was not effective on inhibition of the plasmid carrying hypothetical ampicillin resistant gene. Moreover, the plasmid profiles obtained from probiotic-treated isolates were identical to untreated isolates.


1. Morgan MG, McKenzie H. Controversies in the laboratory diagnosis of community-acquired urinary tract infection. Eur J Clin Microbiol Infect Dis 1993;12:491-504.
2. Stamm WE, Norrby SR. Urinary tract infections: disease panorama and challenges. J Infect Dis 2001;183:S1-4.
3. Mandell GL, Bennett JE, Dolin R. Principles and practice of infectious diseases: Churchill Livingstone;pp 430-4; 2005.
4. Madigan MT, Martinko JM, Brock TD. Brock biology of microorganisms. 11th ed. Upper Saddle River, NJ: Pearson Prentice Hall;pp235-7; 2006.
5. Podschun R, Ullmann U. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin Microbiol Rev 1998 ;11:589-603.
6. Zinsser H, Joklik WK. Zinsser microbiology. 20th ed. Norwalk, CT: Appleton & Lange;pp 650-2; 1992.
7. Facklam RR, Collins MD. Identification of Enterococcus species isolated from human infections by a conventional test scheme. J Clin Microbiol 1989 ;27 :731-4.
Lactobacillus strains as a probiotic against MDR UTI agents Naderi et al
8. Dzidic S, Suskovic J, Kos B. Antibiotic resistance mechanisms in bacteria: Biochemical and genetic aspects. Food Technol Biotech 2008;46:11-21.
9. Strohl WR. Biotechnology of antibiotics. 2nd ed. New York: M. Dekker;pp 620-1; 1997.
10. Benton B, Breukink E, Visscher I, Debabov D, Lunde C, Janc J,et al, editors. Telavancin inhibits peptidoglycan biosynthesis through preferential targeting of transglycosylation: evidence for a multivalent interaction between telavancin and lipid II. 17th European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) & 25th International Congress of Chemotherapy (ICC); 2007 Monday, April 02,; South San Francisco, US; Utrecht, NL.
11. Leach KL, Swaney SM, Colca JR, McDonald WG, Blinn JR, Thomasco LM,et al. The site of action of oxazolidinone antibiotics in living bacteria and in human mitochondria. Mol Cell 2007;26 :393-402.
12. Tenover FC. Mechanisms of antimicrobial resistance in bacteria. Am J Med 2006;11:S3-10.
13. Straus SK, Hancock RE. Mode of action of the new antibiotic for Gram-positive pathogens daptomycin: comparison with cationic antimicrobial peptides and lipopeptides. Biochim Biophys Acta 2006 ;1758:1215-23.
14. Mobashery S, Jr EFA. Bacterial Antibiotic Resistance pp; 123-6;2003.
15. Walsh C. Molecular mechanisms that confer antibacterial drug resistance. Nature 2000 17;406:775-81.
16. Wright GD. Bacterial resistance to antibiotics: enzymatic degradation and modification. Adv Drug Deliv Rev 2005;57:1451-1470.
17. Greene WA, Gano AM, Smith KL, Hogan JS, Todhunter DA. Comparison of probiotic and antibiotic intramammary therapy of cattle with elevated somatic cell counts. J Dairy Sci 1991;74:2976-2981.
18. Tagg JR, Dierksen KP. Bacterial replacement therapy: adapting 'germ warfare' to infection prevention. Trends Biotechnol 2003;21:217-223.
19. Reid G. The scientific basis for probiotic strains of Lactobacillus. Appl Environ Microbiol. 1999 Sep ;65:3763-3766.
20. Anas M, Jamal Eddine H, Mebrouk K. Antimicrobial activity of Lactobacillus species isolated from Algerian raw goat’s milk against
Staphylococcus aureus. World J Dairy Food Sci 2008;3: 39-49.
21. Ennahar S, Sashihara T, Sonomoto K, Ishizaki A. Class IIa bacteriocins: biosynthesis, structure and activity. FEMS Microbiol Rev 2000;24:85-106.
22. McAuliffe O, Ross RP, Hill C. Lantibiotics: structure, biosynthesis and mode of action. FEMS Microbiol Rev 2001;25:285-308.
23. Gilliland SE, Walker DK. Factors to consider when selecting a culture of Lactobacillus acidophilus as a dietary adjunct to produce a hypocholesterolemic effect in humans. J Dairy Sci 1990;73:905-911.
24. Battcock M, Azam-Ali S. Fermented Frutis and Vegetables. A Global Perspective. United Nations Rome Fao Agricultural Services Bulletin; pp 10-15; 1998.
25. Hutt P, Shchepetova J, Loivukene K, Kullisaar T, Mikelsaar M. Antagonistic activity of probiotic lactobacilli and bifidobacteria against entero- and uropathogens. J Appl Microbiol 2006;100:1324-1332.
26. De Vuyst L, Leroy F. Bacteriocins from lactic acid bacteria: production, purification, and food applications. J Mol Microbiol Biotechnol 2007;13:194-199.
27. Simova ED, Beshkova DB, Dimitrov Zh P. Characterization and antimicrobial spectrum of bacteriocins produced by lactic acid bacteria isolated from traditional Bulgarian dairy products. J Appl Microbiol 2009 ;106:692-701.
28. Forbes BA, Sahm DF, Weissfeld AS. Bailey & Scott's diagnostic microbiology. 12th ed. St. Louis: Mosby Elsevier;pp 1031; 2007.
29. Mac Faddin JF. Biochemical tests for identification of medical bacteria. 3rd ed. Philadelphia: Lippincott Williams & Wilkins;pp350-3; 2000.
30. Wikler MA, Clinical and Laboratory Standards Institute. Methods for Dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically: Approved Standard: Clinical and Laboratory Standards Institute;pp 920-22; 2009.
31. Wayne, National Committee for Clinical Laboratory Standards. Performance standards for antimicrobial disk susceptibility tests;Approved standard M2-A7. PA,USA: National Committee for Clinical Laboratory Standards;pp 900-2; 2000.
32. Chin SC, Abdullah N, Siang TW, Wan HY. Plasmid profiling and curing of Lactobacillus strains isolated from the gastrointestinal tract of chicken. J Microbiol 2005; 43:251-256.
33. Sambrook J, Fritsch EF, Maniatis T. Molecular cloning: a laboratory manual: Cold Spring Harbor Laboratory;pp 720-5; 1989.
34. Kothari A, Sagar V. Antibiotic resistance in pathogens causing community-acquired urinary tract infections in India: a multicenter study. J Infect Dev Ctries 2008;2:354-358.
35. Falagas ME, Betsi GI, Tokas T, Athanasiou S. Probiotics for prevention of recurrent urinary tract infections in women: a review of the evidence from microbiological and clinical studies. Drugs 2006;66:1253-1261.
36. Reid G, Beuerman D, Heinemann C, Bruce AW. Probiotic Lactobacillus dose required to restore and maintain a normal vaginal flora. FEMS Immunol Med Microbiol 2001;32(1):37-41.
37. Reid G, Bruce AW, Fraser N, Heinemann C, Owen J, Henning B. Oral probiotics can resolve urogenital infections. FEMS Immunol Med Microbiol 2001 ;30:49-52.
38. Alakomi HL, Skytta E, Saarela M, Mattila-Sandholm T, Latva-Kala K, Helander IM. Lactic acid permeabilizes gram-negative bacteria by disrupting the outer membrane. Appl Environ Microbiol 2000 ;66:2001-2005.
39. Hengstler KA, Hammann R, Fahr AM. Evaluation of BBL CHROMagar orientation medium for detection and presumptive identification of urinary tract pathogens. J Clin Microbiol 1997;35:2773-2777.
40. Chan RC, Bruce AW, Reid G. Adherence of cervical, vaginal and distal urethral normal microbial flora to human uroepithelial cells and the inhibition of adherence of gram-negative uropathogens by competitive exclusion. J Urol 1984 ;131:596-601.
41. Livermore DM. beta-Lactamases in laboratory and clinical resistance. Clin Microbiol Rev 1995;8:557-584.