Antibacterial Effect of Camellia, Juglans, and Hippophae spp. on Methicillin-Resistant Strains of S. epidermidis and S. hemolyticus in Urine Samples

Abstract

Object

To investigate the antibacterial activity of Camellia sinensis, Juglans regia and Hippophae rhamnoides extracts on methicillin-resistant strains of Staphylococcus epidermidis and Staphylococcus hemolyticus.

Background

Coagulase negative staphylococci (CoNS) which were once considered avirulent and usually contaminants when isolated from urine samples are becoming increasingly recognized as agents of clinically significant nosocomial infections. These pathogens are also steadily becoming resistant to conventional antibiotics available as well as combination drugs, highlighting the need for alternative or synergistic natural antimicrobial products that are effective, inexpensive and non-toxic. 

Methods

300 urine samples from hospitalized patients with indwelling catheters were tested for CoNS. Methicillin resistant strain of S. hemolyticus and methicillin resistant strain of S. epidermidis were found amongst others using standard microbiological procedures. Identification was done by API-staph and 16S rRNA gene sequencing using ATCC cultures as control. The antibacterial activity of aqueous extracts of green tea leaves (Camellia spp.), dandasa: dried bark of the walnut tree (Juglans spp.), and sea-buckthorn berries (Hippophae spp.) were investigated on the CoNS isolates, in duplicate, using Microtube-dilution method for Minimum
Inhibitory Concentration (MIC) estimation. 

Results

Amongst the CoNS isolated, 19% were S. epidermidis and 15% were S. hemolyticus. Methicillin resistance observed was above 60%. Of which, 51% of the S. epidermidis strains and 89% of the S. hemolyticus strains were found to be sensitive to the tested extracts. The average MICs of extracts for the S. epidermidis were found to be 1250 ug/ml for green tea, 312.5 ug/ml for Dandasa and 156.25 ug/ml for sea-buckthorn. S. hemolyticus strain, however, showed the average MICs of 625ug/ml for green tea, 2500ug/ml for dandasa and 39.06 ug/ml for sea-buckthorn. 

Conclusion

Our results indicate that extracts of green tea leaves, dried bark of walnut tree, and sea-buckthorn berries may contain compounds with important therapeutic activities, encouraging further study.