RESUMO
Antibiotic collateral sensitivity (CS) occurs when a bacterium that acquires resistance to a treatment drug exhibits decreased resistance to a different drug. Here we identify reciprocal CS networks and candidate genes in Burkholderia multivorans. Burkholderia multivorans was evolved to become resistant to each of six antibiotics. The antibiogram of the evolved strain was compared with the immediate parental strain to determine CS and cross-resistance. The evolution process was continued for each resistant strain. CS interactions were observed in 170 of 279 evolved strains. CS patterns grouped into two clusters based on the treatment drug being a ß-lactam antibiotic or not. Reciprocal pairs of CS antibiotics arose in ≥25% of all evolved strains. A total of 68 evolved strains were subjected to whole-genome sequencing and the resulting mutation patterns were correlated with antibiograms. Analysis revealed there was no single gene responsible for CS and that CS seen in B. multivorans is likely due to a combination of specific and non-specific mutations. The frequency of reciprocal CS, and the degree to which resistance changed, suggests a long-term treatment strategy; when resistance to one drug occurs, switch to use of the other member of the reciprocal pair. This switching could theoretically be continued indefinitely, allowing life-long treatment of chronic infections with just two antibiotics.
Assuntos
Antibacterianos/farmacologia , Infecções por Burkholderia/tratamento farmacológico , Burkholderia/efeitos dos fármacos , Burkholderia/genética , Sensibilidade Colateral a Medicamentos/genética , Farmacorresistência Bacteriana/genética , Burkholderia/isolamento & purificação , Fibrose Cística/patologia , Sensibilidade Colateral a Medicamentos/efeitos dos fármacos , Genoma Bacteriano/genética , Humanos , Pulmão/microbiologia , Pulmão/patologia , Testes de Sensibilidade Microbiana , Sequenciamento Completo do Genoma , beta-Lactamas/farmacologiaRESUMO
The methods used to generate antibiotic-resistant bacterial strains can be labour-intensive, costly, lengthy and/or prone to plate-to-plate variation. We propose a simple, inexpensive and easily replicated method to expose bacteria to a continuous gradient of antibiotic concentration, providing an environment of positive selective pressure for evolution of antibiotic-resistant strains.
Assuntos
Antibacterianos/farmacologia , Evolução Biológica , Complexo Burkholderia cepacia/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Adaptação Biológica/efeitos dos fármacos , Complexo Burkholderia cepacia/fisiologia , Testes de Sensibilidade MicrobianaRESUMO
Antimicrobial susceptibility testing can be done using solid or liquid-based medium. Solid-based assays are easy and inexpensive; they are limited by not being as quantitative as liquid-based assays. Agar depth can influence the accuracy of plate-based assays and it is assumed the basis of this effect is antimicrobial agent diffusion. We tested this assumption by using ETEST® to quantitate the relationship between agar depth and minimum inhibitory concentration and zone of inhibition.
