(2004). The rpoD sequence of the A. taiwanensis strain H53AQ1 recovered from faeces of a patient living in the same area (Senderovich et al., 2012)

grouped with the environmental strains (Fig. 1) but it differed in 16–23 nucleotides, which indicates that they were not clonally related. Although no epidemiological relationship could be established in this case, the same Aeromonas clone that caused diarrhoea had been isolated from drinking water in other studies (Khajanchi et al., 2010; Pablos et al., 2010). Recently, four A. sanarellii and one A. taiwanensis isolates were recovered from waste water in Portugal (Figueira et al., 2011), which could have originally come from human faeces similar to the A. taiwanensis strain reported by Senderovich et al. (2012) in Israel. Considering this, waste water could have been the dispersion route of both bacterial species to natural buy KU-60019 water environments such as those inhabited by chironomids. Either these nonbiting midges or the waste water could be the source of the contamination of drinking water with Aeromonas.

Genetic identification on the basis of the rpoD gene has revealed that the most abundant species in patients suffering from diarrhoea in Israel were as follows: A. caviae (65%), A. veronii (29%) and A. taiwanensis (6%) (Senderovich et al., 2012). This identification approach provides results equal to those obtained when using two or more housekeeping genes (Figueira et al., 2011; Figueras et al., 2011a, b), and once more, it has proven to be a reliable method. More studies from other AZD2014 concentration geographical regions using a similar reliable approach will help to establish the true prevalence of these still poorly known Aeromonas species.

The biochemical traits Florfenicol observed for A. taiwanensis and A. sanarellii, which include both variable and stable characters when compared with those originally described only on the basis of the type strains, enabled the phenotypic diversity of these two species to be defined for the first time. In addition, it reveals which of the tests is more valuable for their recognition. Among the tests carried out, acid production of d-cellobiose and growth at 45 °C in sheep blood agar were the ones that differentiated both of these species from their closest relative A. caviae (Table S1). However, based on previously published results, it must be considered that only about 85% of A. caviae strains produce acid from cellobiose (Figueras et al., 2009). Furthermore, the use of citrate as a sole carbon source might discriminate A. sanarellii from A. taiwanensis and A. caviae. Both A. sanarellii and A. taiwanensis can also be differentiated from A. hydrophila by the Voges–Proskauer test, gas production from glucose and growth at 45 °C in sheep blood agar, all positive for A. hydrophila but negative for the other two species (Table S1).