In Vitro efficacy of antimicrobial extracts against the atypical ruminant pathogen Mycoplasma mycoides subsp. capri

Abstract

BackgroundMycoplasmosis is a common infection in human and veterinary medicine, and is associated with chronic inflammation and high morbidity. Mycoplasma species are often intrinsically resistant to many conventional antimicrobial therapies, and the resistance patterns of pathogenic mycoplasmas to commonly used medicinal (antimicrobial) plant extracts are currently unknown.MethodsAqueous extracts, ethanol extracts, or oils of the targeted plant species and colloidal silver were prepared or purchased. Activity against the wall-less bacterial pathogen Mycoplasma mycoides subsp. capri was determined and compared to activities measured against Escherichia coli and Bacillus subtilis. Antimicrobial susceptibility testing was performed by broth microdilution assays. The lethal or inhibitory nature of each extract was determined by subculture into neat growth medium.ResultsGrowth of M. mycoides capri, E. coli, and B. subtilis was inhibited by elderberry extract, oregano oil, ethanol extract of oregano leaves, and ethanol extract of goldenseal root. No inhibition was seen with aqueous extract of astragalus or calendula oil. Growth of M. mycoides capri and B. subtilis was inhibited by ethanol extract of astragalus, whereas growth of E. coli was not. Similarly, M. mycoides capri and E. coli were inhibited by aqueous extract of thyme, but B. subtilis was unaffected. Only B. subtilis was inhibited by colloidal silver. Measured MICs ranged from 0.0003 mg/mL to 3.8 mg/mL. Bacteriostatic and bactericidal effects differed by species and extract.ConclusionsThe atypical pathogen M. mycoides capri was sensitive to extracts from many medicinal plants commonly used as antimicrobials in states of preparation and concentrations currently available for purchase in the United States and Europe. Variation in bacteriostatic and bactericidal activities between species and extracts indicates that multiple effecter compounds are present in these plant species.

Antimycoplasmic activity and seasonal variation of essential oil of Eugenia hiemalis Cambess. (Myrtaceae)

“…These results were more promising than those of previous reports in the literature with EOs from the leaves of E. brasiliensis (Siebert et al 2015) and Thyme vulgaris (Arjoon et al 2012). …”

Selected ethno-medicinal plants from Kenya with in vitro activity against major African livestock pathogens belonging to the “ Mycoplasma mycoides cluster”

“…The broth microdilution method as described by Arjoon et al (2012) was used to characterize the in vitro antimycoplasmal activity of plant extracts and to determine the minimum inhibitory concentrations employing serial dilutions of the plant extracts. Briefly, a stock solution of 100 mg/ml was prepared and 10 µl (1 mg) of the same was used as the initial concentration mixed with 1 ml of cell culture (1 mg/ml) for the antibacterial test.…”

“…The MICs of all the active extracts were determined by broth microdilution as previously described by Arjoon et al (2012) starting from 1 mg/ml to 0.000005 mg/ml. The experiment was repeated thrice for each assay and mean was recorded.…”

Antimycoplasmal Activities of Compounds from Solanum aculeastrum and Piliostigma thonningii against Strains from the Mycoplasma mycoides Cluster

“…Mycoplasma s are distinguished phenotypically from other bacteria by their small size and total lack of a cell wall ( Weisburg et al, 1989 ). Infections caused by these Mycoplasma constitute a threat to both humans and animals ( Arjoon et al, 2012 ). Many species belonging to these classes are pathogenic and of great economic concern in livestock production ( Tambi et al, 2006 ).…”