Chironomid egg masses harbour the clinical species Aeromonas taiwanensis and Aeromonas sanarellii

Bacteria of the genus Aeromonas are found worldwide in aquatic environments and may produce human infections. In 2010, two new clinical species, Aeromonas sanarellii and Aeromonas taiwanensis, were described on the basis of one strain recovered from wounds of hospitalized patients in Taiwan. So far, only four environmental isolates of A. sanarellii and one of A. taiwanensis have been recorded from waste water in Portugal and an additional clinical strain of A. taiwanensis from the faeces of a patient with diarrhoea in Israel. In the present study, strains belonging to these two species were identified from chironomid egg masses from the same area in Israel by sequencing the rpoD gene. This represents a new environmental habitat for these novel species. The first data on the virulence genes and antibiotic susceptibility are provided. The isolates of these two new species possess multiple virulence genes and are sensitive to amikacin, aztreonam, cefepime, cefoxatime, ceftazidime, ciprofloxacin, gentamicin, piperacillintazobactam, tigecycline, tobramycin, trimethoprimsulfamethoxazole and imipenem. The key phenotypic tests for the differentiation of these new species from their closest relative Aeromonas caviae included the utilization of citrate, growth at 45 degrees C in sheep blood agar and acid production of cellobiose.