| Title | Susceptibility to Antibiotics of Vibrio sp AO1 Growing in Pure Culture or in Association with its Hydroid Host Aglaophenia octodonta (Cnidaria, Hydrozoa) |
| Abstract | Vibrio harveyi is the major causal organism of vibriosis, causing potential devastation to diverse ranges of marine invertebrates over a wide geographical area. These microorganisms, however, are phenotypically diverse, and many of the isolates are also resistant to multiple antibiotics. In a previous study, we described a previously unknown association between Vibrio sp. AO1, a luminous bacterium related to the species V. harveyi, and the benthic hydrozoan Aglaophenia octodonta. In this study, we analyzed the susceptibility to antibiotics (ampicillin, streptomycin, tetracycline, or co-trimoxazole = mix of sulfamethoxazole and trimetoprim) of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host by using microcosm experiments. The results of minimum inhibitory concentration (MIC) experiments demonstrated that Vibrio sp. AO1 was highly resistant to ampicillin and streptomycin in pure culture. Nevertheless, these antibiotics, when used at sub-MIC values, significantly reduced the hydroid fluorescence. Co-trimoxazole showed the highest inhibitory effect on fluorescence of A. octodonta. However, in all treatments, the fluorescence was reduced after 48 h, but never disappeared completely around the folds along the hydrocaulus and at the base of the hydrothecae of A. octodonta when the antibiotic was used at concentration completely inhibiting growth in vitro. The apparent discrepancy between the MIC data and the fluorescence patterns may be due to either heterogeneity of the bacterial population in terms of antibiotic susceptibility or specific chemical-physical conditions of the hydroid microenvironment that may decrease the antibiotic susceptibility of the whole population. The latter hypothesis is supported by scanning electron microscope evidence for development of bacterial biofilm on the hydroid surface. On the basis of the results obtained, we infer that A. octodonta might behave as a reservoir of antibiotic multiresistant bacteria, increasing the risk of their transfer into aquaculture farms. |
| Source | Microbial ecology 59, pp. 555–562 |
| Keywords | AntibioticsVibrioHydroidsAglaophenia octodonta |
| Journal | Microbial ecology |
| Editor | Springer-Verlag,, New York,, Stati Uniti d'America |
| Year | 2010 |
| Type | Articolo in rivista |
| DOI | 10.1007/s00248-009-9605-x |
| Authors | Stabili L., Gravili C., Boero F., Tredici M., Alifano P. |
| Text | 6907 2010 10.1007/s00248 009 9605 x ISI Web of Science WOS 000276745200014 Scopus 2 s2.0 77952517237 PubMed 19888625 Antibiotics Vibrio Hydroids Aglaophenia octodonta Susceptibility to Antibiotics of Vibrio sp AO1 Growing in Pure Culture or in Association with its Hydroid Host Aglaophenia octodonta Cnidaria, Hydrozoa Stabili L., Gravili C., Boero F., Tredici M., Alifano P. CNR IAMC U.O.S. di Taranto DiSTeBA, Universita del Salento Vibrio harveyi is the major causal organism of vibriosis, causing potential devastation to diverse ranges of marine invertebrates over a wide geographical area. These microorganisms, however, are phenotypically diverse, and many of the isolates are also resistant to multiple antibiotics. In a previous study, we described a previously unknown association between Vibrio sp. AO1, a luminous bacterium related to the species V. harveyi, and the benthic hydrozoan Aglaophenia octodonta. In this study, we analyzed the susceptibility to antibiotics ampicillin, streptomycin, tetracycline, or co trimoxazole = mix of sulfamethoxazole and trimetoprim of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host by using microcosm experiments. The results of minimum inhibitory concentration MIC experiments demonstrated that Vibrio sp. AO1 was highly resistant to ampicillin and streptomycin in pure culture. Nevertheless, these antibiotics, when used at sub MIC values, significantly reduced the hydroid fluorescence. Co trimoxazole showed the highest inhibitory effect on fluorescence of A. octodonta. However, in all treatments, the fluorescence was reduced after 48 h, but never disappeared completely around the folds along the hydrocaulus and at the base of the hydrothecae of A. octodonta when the antibiotic was used at concentration completely inhibiting growth in vitro. The apparent discrepancy between the MIC data and the fluorescence patterns may be due to either heterogeneity of the bacterial population in terms of antibiotic susceptibility or specific chemical physical conditions of the hydroid microenvironment that may decrease the antibiotic susceptibility of the whole population. The latter hypothesis is supported by scanning electron microscope evidence for development of bacterial biofilm on the hydroid surface. On the basis of the results obtained, we infer that A. octodonta might behave as a reservoir of antibiotic multiresistant bacteria, increasing the risk of their transfer into aquaculture farms. 59 Published version http //www.springer.com/life sciences/microbiology/journal/248 Susceptibility to Antibiotics of Vibrio sp AO1 Growing in Pure Culture or in Association with its Hydroid Host Aglaophenia octodonta micecol_2010.pdf Articolo in rivista Springer Verlag, 0095 3628 Microbial ecology Microbial ecology Microb Ecol Microbial ecology. loredana.stabili STABILI LOREDANA TA.P04.002.001 Fascia Costiera e Ambienti di Transizione analisi strutturale e funzionale delle componenti biotiche ed abiotiche degli ecosistemi per lo sviluppo sostenibile delle attivita TA.P04.029.002 Utilizzazione di biomasse e sostanze attive da organismi marini biotecnologie per loo sviluppo di nuovi bio materiali e composti bioattivi |
