Antimicrobial Effects of Different Types of Honey against Staphylococcus aureus and Pseudomonas aeruginosa Saad B. Almasaudi, Alaa A. M. Al-Nahari, Soad K. Al Jaouni and Steve Harakeh

( وأوحى ربك إلى النحل أن اتخذي من الجبال بيوتاً ومن الشجر ومما يعرشون * ثمَّ كلي من كل الثمرات فاسلكي سبل ربك ذللاً يخرج من بطونها شرابٌ مختلفٌ ألوانه فيه شفاء للناس، إنَّ في ذلك لآية لقومٍ يتفكرون ).. سورة النحل 68، 69

Staphylococcus aureus Staphylococci are Gram-positive cocci. Most staphylococci constitute the normal flora of the skin and mucus membranes. The most pathogenic species is S. aureus which has developed over the years resistance to methicillin and makes it extremely difficult to treat. Lately there has been an increase in the prevalence and incidence of methicillin resistant S. aureus, making it more challenging to eliminate and has been involved in hospital- acquired infections.

Pseudomonas aeruginosa Extremely broad host spectrum Hardly any infections in the normal human host Severe immunodeficiencies and medical devices predispose the patients to P. aeruginosa infections Broad spectrum of clinical symptoms –Urinary tract infections –Pulmonary infections –Soft tissue infections –Sepsis –Bone and joint infections –Endocarditis

Pseudomonas aeruginosa Fourth most common isolated nosocomial pathogen accounting for approx. 10 % of all hospital acquired infections. Patient-to-patient spread and direct patient contact with environmental reservoirs –disinfectants, –respiratory equipment, –food, –sinks, taps –P. aeruginosa is frequently resistant to many commonly used antibiotics.

Antimicrobial Resistance Over the years, Bacteria has evolved and developed resistance to commonly used antimicrobial agents. For this reason, agents including natural products have been sought to deal with such a worldwide problem. Honey has been considered as a possible promising agent. The objective of this study is to compare the efficacy of five types of honey against S. aureus, and P. aeuroginosa.

Antimicrobial Effects of Honey Honey has been used since ancient times in various applications in medicine. It has shown a broad spectrum of activity against various types of microorganisms. It has been effective in wound healing. Honey is composed of around 200 different components, and this makes it more efficient antimicrobial agent and will not allow bacterial resistance to develop.

MATERIALS AND METHODS Honey Types: Five types of honey were used: Active +10 Manuka Honey, Manuka Honey UMF +16, Manuka Honey UMF +20, Seder honey and Nigella sativa honey

Bacteria used Methicillin sensitive S. aureus (MSSA): Ten clinical isolates of MSSA. Methicillin resistant S. aureus: Ten strains of clinical isolates of MRSA Imipenem sensitive Pseudomonas aeruginosa: Ten clinical isolates Imipenem resistant Pseudomonas aeruginosa: Ten clinical isolates

Antimicrobial Evaluation  Antimicrobial efficacy of honey was evaluated using Mueller-Hinton Agar.  Different volumes of honey were added to molten warm agar (50-55°C) to achieve the required concentration in the resulting Petri dishes. 1mL of each of the tested bacteria was inoculated onto those plates and incubated for 24 hours at 37°C and then colony forming units were counted (CFU/ml).

Bactericidal/bacteriostatic effects of honey: To evaluate the bacteriostatic /bactericidal activity of honey, 50% (v/v) of each one of following types of honey: Manuka Honey UMF +20, Sidr honey and Nigella sativa were dispensed into sterile tubes( this concentration resulted in the complete inhibition of bacterial growth).

1 ml of each of the test bacterial strains was inoculated into those tubes and incubated for 24 hours at 37 0 C. In order to verify whether the honey has a bacteriostatic /bactericidal, 1 mL was added to 9 mL broth without honey and incubated for 24, 48 and 72 hours. 0.1 ml of those cultures were placed on nutrient agar (free of honey) for 24 hours to check for signs of bacterial growth, the honey type was considered as bacteriostatic if growth occurred and bactericidal when inhibition of growth persisted..

Results

Bacteriostatic and Bactericidal effect of honey (-) Bactericidal effect. (+) Bacteriostatic effect