In vitro additive effect of Hyptis martiusii in the resistance to aminoglycosides of methicillin-resistant Staphylococcus aureus.
BACKGROUND
Bacterial infectious agents represent a risk to populations, where they are responsible for the high morbidity and mortality. In combating these pathogens, our main line of defense is the use of antibiotics. However, the indiscriminate use of these drugs select resistant strains to these same drugs.


OBJECTIVE
In this study the ethanol extract of Hyptis martiusii Benth. (EEHM) (Lamiaceae) was tested for its antimicrobial activity against aminoglycoside multi-resistant Staphylococcus aureus (MRSA).


METHODS
In this study, the ethanol extract of H. martiusii was prepared and tested with chlorpromazine for its antimicrobial activity using the microdilution method. Chlorpromazine and the ethanol extract were used alone and also in combination with aminoglycosides against a MRSA strain resistant to these antibiotics to determine the participation of efflux systems in resistance mechanisms. The FIC index was calculated and evaluated by the checkerboard method.


RESULTS
A potentiating effect between this extract and aminoglycosides was demonstrated. Similarly, a potentiating effect of chlorpromazine with kanamycin was detected, indicating the involvement of an efflux system in the resistance to this aminoglycoside. The checkerboard method with combinations of aminoglycosides and EEHM demonstrated additive effect with kanamycin and gentamicin. It is therefore suggested that extracts from H. martiusii could be used as a source of plant-derived natural products with resistance- modifying activity.


CONCLUSIONS
This is the first report about the modifying antibiotic activity of Hyptis martiusii, constituting a new approach against bacterial resistance to antibiotics as aminoglycosides.
Coutinho
Henrique D M
HD
Laboratory of Research in Natural Products, University of the Region of Cariri, Crato, CE, Brazil. hdmcoutinho@gmail.com
Costa
José G M
JG
Falcão-Silva
Vivyanne S
VS
Siqueira-Júnior
José P
JP
Lima
Edeltrudes O
EO
D000617:Aminoglycosides / Q000378:metabolism / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000378:metabolism / Q000494:pharmacology*; D002746:Chlorpromazine / Q000378:metabolism / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D004357:Drug Synergism; D005839:Gentamicins / Q000378:metabolism / Q000494:pharmacology; D031331:Hyptis / Q000737:chemistry*; D007612:Kanamycin / Q000378:metabolism / Q000494:pharmacology; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D013203:Staphylococcal Infections / Q000188:drug therapy
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D010936:Plant Extracts; D007612:Kanamycin; D002746:Chlorpromazine