Synergistic effect of Thymbra spicata L. extracts with antibiotics against multidrug- resistant Staphylococcus aureus and Klebsiella pneumoniae strains

Document Type: Original Article


1 Faculty of Pharmacy, Al Andalus University for Medical Sciences, Syria

2 Faculty of Pharmacy, Aleppo University, Syria

3 Public Health Department, Center for Strategic Studies and Research, Aleppo University, Syria


Objective(s): To evaluate the in vitro interaction between different extracts of Thymbra spicata L. and certain antimicrobial drugs of different mechanisms, including ampicillin, cefotaxime, amikacin and ciprofloxacin. This study was performed against multidrug-resistant strains of Staphylococcus aureus and Klebsiella pneumoniae.
Materials and Methods: Evaluation of antibacterial activity and synergy interaction between plant extracts and antimicrobial agents was carried out using checkerboard microdilution.
Results: Different interactions (synergistic, additive and indifference) were observed between plant crude extracts and used antibiotics depending on the strain. The fractional inhibitory concentration (FIC) index ranged from 0.02 to 1.5 for S. aureus and 0.25 to 2 for K. pneumoniae strains. The best synergistic capacity appeared with cefotaxime against S. aureus strains, where the activity of cefotaxime was increased from 8- to 128-fold.
Conclusion: These results may indicate that T. spicata extracts potentiates the antimicrobial action of antibiotics, suggesting a possible utilization of this herb in combination therapy against emerging multidrug-resistance S. aureus and K. pneumoniae.


1.Boucher HW, Talbot GH, Bradley JE, Edwards Jr, Gilbert D, Rice LB, et al. Bad bugs, no drugs: no escape! An update from the infectious diseases society of America. Clin Infect Dis 2009; 48:1–12.

2.Harbarth S, Samore MH. Antimicrobial resistance determinants and future control. Emerg Infect Dis 2005; 11:794-801.

3.Spellberg B, Bartlett JG, Gilbert DN. The future of antibiotics and resistance. N Engl J Med 2013; 368: 299–302.

4.Torella JP, Chait R, Kishony R. Optimal drug synergy in antimicrobial treatments. PLoS Comput Biol 2010; 6:1-8.

5.Sibanda T, Okoh AI. The challenges of overcoming antibiotic resistance: Plant extracts as potential sources of antimicrobial and resistance modifying agents. Afr J Biotechnol 2007; 6:2886-2896.

6.Adwan G, Abu-Shanab B, Adwan K. Antibacterial activities of some plant extracts alone and in combination with different antimicrobials against multidrug-resistant Pseudomonas aeruginosa strains. Asian Pac J Trop Biomed 2010; 1:266-269.

7.Darwish RM, Aburjai TA. Effect of ethnomedicinal plants used in folklore medicine in Jordan as antibiotic resistant inhibitors on Escherichia coli. BMC Complement Altern Med 2010; 10:9-16.

8.Hübsch Z, van Zyl RL, Cock IE, van Vuuren SF. Interactive conventional antimicrobial and toxicity profiles of antimicrobials with Southern African medicinal plants. S Afr J Bot 2014; 93:185–197.

9.Bassolé IH, Juliani HR. Essential oils in combination and their antimicrobial properties. Molecules 2012; 17:3989-4006.

10.Aiyegoro OA, Okoh AI. Use of bioactive plant products in combination with standard antibiotics: Implications in antimicrobial chemotherapy. J Med Plant Res 2009; 3:1147-1152.

11.Gibbons S. Anti-staphylococcal. Nat Prod Rep 2004; 21:263–277.

12.Hemaiswarya S, Kruthiventi AK, Doble M. Synergism between natural products and antibiotics against infectious diseases. Phytomedicine 2008; 15:639–652.

13.Mouterde P. Nouvelle flore du Liban et de la Syrie. Tome III, Dar El Mashreq, Liban: 1983.

14.Barakata A, Wakimb LH, Apostolidesb NA, Sroura G, El Beyrouthyb M. Variation in the essential oils of Thymbra spicata L. growing wild in Lebanon, according to the date of harvest. J Essent Oil Res 2013; 25:506-511.

15.Marković T, Chatzopoulou P, Šiljegović J, Nikolic M, Glamo J, Ćirić A, et al Chemical analysis and antimicrobial activities of the essential oils of Satureja thymbra L. and Thymbra spicata L. and their main components. Arch Biol Sci 2011; 63:457-464.

16.Celiktas OY, Kocabas EEH, Bedir E, Sukan FV, Ozek T, Baser KHC. Antimicrobial activities of methanol extracts and essential oils of Rosmarrinus officinalis, depending on location and seasonal variations. Food Chem 2007; 100:553-559.

17.Balouiri M, Sadiki M, Ouedehiri W, Farah A, Abed S, Koraichi SI. Antibacterial activity of extracts from Salvia officinalis and Rosmarinus officinalis obtained by sonication and maceration methods. Int J Pharm Pharm Sci 2014; 6:167-170.

18.National Committee for Clinical Laboratory Standards (NCCLS). Performance standards for antimicrobial disk and dilution susceptibility tests for bacteria isolated from animals. Pennsylvania: NCCLS 2013; M100-S23.

19.Klančnik A, Piskernik S, Jeršek B, Možina SS. Evaluation of diffusion and dilution methods to determine the antibacterial activity of plant extracts. J Microbiol Methods 2010; 81:121–126.

20.Vuuren S, Viljoen A. Plant-based antimicrobial studies–methods and approaches to study the interaction between natural products. Planta Med 2011; 77:1168–1182.

21.Styers CD, Sheehan DJ, Hogan P, Sahm DF. Laboratory-based surveillance of current antimicrobial resistance patterns and trends among Staphylococcus aureus: 2005 status in the United States. Ann Clin Microbiol Antimicrob 2006; 5:1-9.

22.Porsche R, Ullmann U. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin Microbiol Rev 1998; 11:589–603.

23.Khameneh B, Diab R, Ghazvini K, Fazly Bazzaz BS. Breakthroughs in bacterial resistance mechanisms and the potential ways to combat them. Microb Pathog 2016; 95:1-11.

24.Kilic TZ. Analysis of essential oil composition of Thymbra spicata var. spicata: antifungal, antibacterial and antimycobacterial activities. Naturforsch 2006; 61:324-328.

25.Akin M, Oguz D, Saracoglu TH. Antibacterial effect of essential oil from Thymbra  spicata var. spicata L. and Teucrium polium (Stapf Brig). Int J Pharm  Appl Sci 2010; 1:55-58. 

26.Markovic T, Chatopoulou P, Siljegovic J. Chemical analysis and antimicrobial activities of the   essential   oils   of   Satureja   thymbra   L.   and Thymbra  spicata  L. and their  main  components. Arch Biol Sci 2011; 63:457-464.

27.Jahan F, Lawrence R, Kumar V, Junaid M. Evaluation of antimicrobial activity of plant extracts on antibiotic-susceptible and resistant Staphylococcus aureus strains. J Chem Pharm Res 3:777-789.

28.Nascimento GGF, Locatelli, J Friestas PC, Silva GL. Antibacterial activity of plant extracts and phytochemicals on antibiotic-resistant bacteria. Braz J Microbiol 2000; 31:345-353.

29.Parekh J, Jadeja D, Hanlin RL. Efficacy of  aqueous  and  methanol  extracts  of  some  medicinal  plants  for  potential  antibacterial  activity.  Turk J Biol 2005; 29:203-210.

30.Omar G, Abdallah LA, Ismail S, Almasri MY. Screening of selected medicinal wild plant extracts antibacterial effect as natural alternatives. Inter J Indig Med Plants 2013; 46:1299-1304.

31.Bakhtiyari S, Sabzali S, Rostamzad A, Basati G. Investigating antimicrobial activity of hydroalcoholic extract and essential oil of Tymbra spicata against some pathogenic bacteria. J Basic Res Med Sci 2014; 1-7.

32.Ilić BS, Kocić BD, Cirić VM, Ćvetković OG, Miladinović DL. An in vitro synergistic interaction of combinations of thymus glabrescens essential oil and its main constituents with chloramphenicol. ScientificWorldJournal 2014; 1:1-12.

33.Betoni JE, Mantovani RP, Barbosa LN, Di Stasi LC, Fernandes JA. Synergism between plant extract and antimicrobial drugs used on Staphylococcus aureus diseases.  Mem Inst Oswaldo Cruz 2006; 10:387-390.

34.Abd El-Kalek HH, Mohamed EA. Synergistic effect of certain medicinal plants and amoxicillin against some clinical isolates of methicillin – resistant Staphylococcus aureus (MRSA). Int J Pharm Appl 2012; 3:387-398.

35.Hübsch Z, van Zyl RL, Cock IE, van Vuuren SF. Interactive antimicrobial and toxicity profiles of conventional antimicrobials with Southern African medicinal plants. S AFR J BOT 2014; 93:185–197.

36.Zhao WH, Hu ZQ, Okubo S, Hara Y, Shimamura T. Mechanism of synergy between Epigallochatechin gallate and β-Lactams against methicillin resistant Staphylococcus   aureus. Antimicrob. Agents Chemother 2012; 45:1737-1742.

37.Esimone CO, Iroha IR, Ibezim EC, Okeh CO, Okpana EM. In vitro evaluation of the interaction between tea extracts and penicillin G against Staphylococcus aureus. Afr J Biotecnol 2006; 5:1082–1086.

38.Georgopapadakou NH.   Penicillin-binding   proteins   and   bacterial   resistance   to   β-Lactams.   Antimicrob   Agents     Chemother 1993; 37:2045-2053.

39.Mingeot-Leclercq MP, Glupczynski Y, Tulkens PM. Aminoglycosides; Activity and resistance. Antimicrob Agents Chemother 1999; 43:727-737.

40.Atteiaa HG, Husseinb EM. In vitro antibacterial and synergistic effects of some plant extracts against Staphylococcus aureus and Klebsiella pneumonia. J Antimicrob 2014; 129:338-346.

41.Chatterjee SK, Bhattacharjee I, Chandra G. In vitro synergistic effect of doxycycline and ofloxacin in

combination with ethanolic leaf extract of Vangueria spinosa against four pathogenic bacteria. Indian J Med Res 2009; 130:475-478.

42.Ghaly MF, Shalaby MA, Shas SM, Shehata MN, Ayad AA. Synergistic effect of antibiotics and plant extract to control clinical bacterial isolates implicated in urinary tract infections. J Appl Sci Res 2009; 5:1298-1306.

43.Chovanová R, Mikulášová M, Vaverková Š. In vitro antibacterial and antibiotic resistance modifying effect of bioactive plant extracts on methicillin-resistant Staphylococcus epidermidis. Int J Microbiol 2013; 2013:760969.

44.Horiuchi K, Shiota S, Kuroda T, Hatano T, Yoshida T, Tsuchiya T. Potentiation of antimicrobial activity of aminoglycosides by carnosol from Salvia officinalis. Biol Pharm Bull 2007; 30:287-290.

45.Adwan G, Mhanna M. Synergistic effects of plant extracts and antibiotics on Staphylococcus aureus strains isolated from clinical specimens. Middle East J Sci Res 2008; 3: 134-139.

46.Ahmed Z, Khan SS, Khan M, Tanveer A, Lone ZA. Synergistic effect of Salvadora persica extracts, tetracycline and penicillin against Staphylococcus aureus. Afr J Basic Appl Sci 2010; 2:25-29.

47.Cristiani M, D’Arrigo M, Mandalari G, Castelli F, Sarpietro MG, Micieli D. Interaction of four monoterpenes contained in essential oils with model membranes: Implications for their antibacterial activity. J Agric Food Chem 2007; 55:6300–6308.

48.Xu J, Zhou F, Ji BP, Pei RS, Xu N. The antibacterial mechanism of carvacrol and thymol against Escherichia coli. Lett Appl Microbiol 2008; 47:174-179.