Evolutionary nursing: the case of infectious diseases

In vitro additive effect of Hyptis martiusii in the resistance to aminoglycosides of methicillin-resistant Staphylococcus aureus

CONTEXT

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).

MATERIALS AND 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.

CONCLUSION

This is the first report about the modifying antibiotic activity of Hyptis martiusii, constituting a new approach against bacterial resistance to antibiotics as aminoglycosides.

Increasing of the aminoglicosyde antibiotic activity against a multidrug-resistant E. coli by Turnera ulmifolia L. and chlorpromazine

In this study, an ethanol extract of Turnera ulmifolia L. (EETU) and chlorpromazine (CPZ) were tested for their antimicrobial activity alone or in combination with conventional antibiotics against two strains of Escherichia coli (E. coli). The growth of neither E. coli strain was inhibited by the extract. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration values were > or =1 mg/ml for both the strains of E. coli. However, the extract did increase the antimicrobial effects of amikacin, neomycin, and tobramycin. A similar effect of CPZ on amikacin, kanamycin, and tobramycin indicated the involvement of an efflux system in the resistance to these aminoglycosides. Results suggest that extracts from T. ulmifolia could be used as a plant-derived natural product with resistance-modifying activity, constituting a new weapon against bacterial resistance to antibiotics.

Herbal therapy associated with antibiotic therapy: potentiation of the antibiotic activity against methicillin--resistant Staphylococcus aureus by Turnera ulmifolia L

Background

Staphylococcus genus is widely spread in nature being part of the indigenous microbiota of skin and mucosa of animal and birds. Some Staphylococcus species are frequently recognized as etiological agents of many animal and human opportunistic infections This is the first report testing the antibiotic resistance-modifying activity of Turnera ulmifolia against methicillin-resistant Staphylococcus aureus – MRSA strain.

Methods

In this study an ethanol extract of Turnera ulmifolia L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with aminoglycosides against an MRSA strain.

Results

The synergism of the ethanol extract and aminoglycosides were verified using microdillution method. A synergistic effect of this extract on gentamicin and kanamycin was demonstrated. Similarly, a potentiating effect of chlorpromazine on kanamycin, gentamicin and neomycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides.

Conclusion

It is therefore suggested that extracts from Turnera ulmifolia could be used as a source of plant-derived natural products with resistance-modifying activity, constituting a new weapon against the problem of bacterial resistance to antibiotics demonstrated in MRSA strains.