All strains were sensitive to 12 of the 19 antimicrobials tested and were resistant to ampicillin, LGK-974 solubility dmso as

expected, but also to cefalotin (Table 2). Both species showed a varying susceptibility to several antimicrobials ranging from 25 to 77.7% and a similar susceptibility against all the antimicrobials tested except for cefazolin for which 44% of A. sanarellii were susceptible and all strains of A. taiwanensis were resistant (Table 2). This is the first antimicrobial susceptibility data presented for the species A. sanarellii and A. taiwanensis. The results of this study agree with previous reported data that indicated that most Aeromonas clinical strains, belonging to several species, were sensitive to amikacin, gentamicin, aztreonam, cefepime, ceftazidime, cefotaxime and ciprofloxacin (Overman & Janda, 1999; Vila CH5424802 clinical trial et al., 2003; Tena et al., 2007; Awan et al., 2009; Senderovich et al., 2012), those therefore being the most active antibiotics for A. sanarellii and A. taiwanensis. The 100% sensitivity to imipenem found for the new species agrees with the data previously reported for other Aeromonas

species (Vila et al., 2003; Senderovich et al., 2012) and was higher than results (65–67%) found by Overman & Janda (1999). In fact, in a recent study, we discovered that imipenem-resistant strains showed an over-expression of the imiS gene, encoding a chromosomal carbapenemase, and this was probably induced in vivo after treatment of a urinary tract infection with amoxicillin–clavulanic acid (Sánchez-Céspedes et al., 2009). Furthermore, strains in this study showed a susceptibility to cefoxatin (69.2%) and amoxicillin–clavulanic acid (30.8%) that was similar (70% and 27%, respectively) to the results reported by Senderovich et al. (2012) for the Aeromonas strains responsible for causing diarrhoea, among which A. taiwanensis was reported. Susceptibility to ciprofloxacin, cefalotin and trimethoprim–sulfamethoxazole was the

characteristic antimicrobial profile of the group of 15 Aeromonas isolates that embraced those of A. sanarellii (n = 4, but three from the same genotype) and A. taiwanensis (n = 1) obtained from waste water in Portugal (Figueira et al., 2011), results which agree with those from the chironomid Thymidine kinase strains. In conclusion, this study shows the presence of A. sanarellii and A. taiwanensis strains in chironomid egg masses, from where they might disseminate to humans through the drinking water supply. Strains of both species bear TTSS genes, among other virulent determinants, and antibiotics such as amikacin, aztreonam, cefepime, cefotaxime, ciprofloxacin, cefalotin, trimethoprim–sulfamethoxazole, gentamicin, ceftazidime and imipenem should be considered potential candidates in the fight against infection produced by these species. The authors thank C.