RESUMO
Ten indole alkaloids were obtained from the marine sponge-associated fungus Neosartorya siamensis KUFA 0017. We studied the antimicrobial properties of these and of three other compounds previously isolated from the soil fungus N. siamensis KUFC 6349. Only neofiscalin A showed antimicrobial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE); with a minimum inhibitory concentration (MIC) of 8 µg mL(-1) against both strains. Another compound, fiscalin C, presented synergistic activity against MRSA when combined with oxacillin, although alone showed no antibacterial effect. Moreover, neofiscalin A, when present at sub-MICs, hampered the ability of both MRSA and VRE strains to form a biofilm. Additionally, the biofilm inhibitory concentration values of neofiscalin A against the MRSA and VRE isolates were 96 and 80 µg mL(-1), respectively. At a concentration of 200 µg mL(-1), neofiscalin A was able to reduce the metabolic activity of the biofilms by â¼50%. One important fact is that our results also showed that neofiscalin A had no cytotoxicity against a human brain capillary endothelial cell line.
Assuntos
Antibacterianos/farmacologia , Bactérias Gram-Positivas/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/tratamento farmacológico , Alcaloides Indólicos/farmacologia , Indóis/farmacologia , Quinazolinas/farmacologia , Biofilmes/efeitos dos fármacos , Descoberta de Drogas , Farmacorresistência Bacteriana Múltipla , Enterococcus faecalis/efeitos dos fármacos , Infecções por Bactérias Gram-Positivas/microbiologia , Humanos , Alcaloides Indólicos/isolamento & purificação , Alcaloides Indólicos/uso terapêutico , Indóis/uso terapêutico , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Neosartorya/química , Neosartorya/metabolismo , Oxacilina/farmacologia , Quinazolinas/uso terapêuticoRESUMO
In this study, microbial quality and antimicrobial resistance of faecal bacteria from a Portuguese river were assessed. River water samples collected upstream and downstream of a wastewater treatment plant, throughout a 3-month period, were used for the enumeration of Escherichia coli and Enterococcus spp. The highest numbers found for E. coli and enterococci were 1.1 × 104 and 1.2 × 104 colony forming units (CFU)/100 ml, respectively. In total, 144 isolates of E. coli and 144 of enterococci were recovered and tested for antimicrobial susceptibility; 104 E. coli and 78 Enterococcus spp. showed resistance to one or more antimicrobial drugs. Overall, 70 and 32 different resistance patterns were found for E. coli and enterococci, respectively. One E. coli showed resistance to imipenem and 29 isolates were extended spectrum ß-lactamase-producers. Multidrug-resistant E. coli belonged mostly to groups A, B1 and group D. Enterococcus spp. were mostly resistant to rifampicin, tetracycline, azithromycin and erythromycin; six isolates showed resistance to vancomycin, presenting the VanA phenotype. The high levels of E. coli and enterococci and the remarkable variety of antimicrobial resistance profiles, reinforces the theory that these river waters can be a pool of antimicrobial resistance determinants, which can be easily spread among different bacteria and reach other environments and hosts.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Enterococcus/efeitos dos fármacos , Monitoramento Ambiental , Escherichia coli/efeitos dos fármacos , Rios/microbiologia , Microbiologia da Água , Contagem de Colônia Microbiana , Enterococcus/genética , Enterococcus/isolamento & purificação , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Testes de Sensibilidade Microbiana , Reação em Cadeia da Polimerase Multiplex , Portugal , Prevalência , Eliminação de Resíduos LíquidosRESUMO
Antimicrobial resistance of enterococci was investigated in 42 samples of crude inflow, treated effluent and sludge collected in 14 municipal sewage treatment plants of Portugal. A total of 983 enterococci were recovered and tested, using the diffusion agar method, regarding their sensitivity to 10 different antimicrobial drugs. Multidrug resistance was present in 49.4% of the isolates. Only 3.3% and 0.6% of the investigated strains were resistant to ampicillin and vancomycin, respectively. Resistances found against rifampicin (51.5%), tetracycline (34.6%), erythromycin (24.8%) and nitrofurantoin (22.5%), are causes for substantial concern. Almost 14% of isolates were resistant to ciprofloxacin. Wastewater treatment resulted in enterococci decrease between 0.5 and 4log; nevertheless, more than 4.4 x 10(5)CFU/100ml were present in the outflow of the plants. Our data indicate that the use of antimicrobials had created a large pool of resistance genes and that sewage treatment processes are unable to avoid the dissemination of resistant enterococci into the environment.