First record of the rare species Aeromonas culicicola from a drinking water supply

Abstract

We describe the recovery of the rare species Aeromonas culicicola, so far known only in mosquitoes in India, from a drinking water supply in Spain. Typing, using enterobacterial repetitive intergenic consensus-PCR, revealed that the 27 new isolates belonged to 3 very closely related strains. These strains were genetically identified by 16S rRNA gene sequencing. Spanish strains differed from the mosquito strains in three nucleotide positions. The AHCYTOEN gene was present in these water strains, which may have a public health significance.

FIG. 1.

Dendrogram based on UPGMA clustering of Dice correlation values (S_D) of ERIC patterns of 27 isolates from drinking water and reference strains of A. culicicola (CECT 5761^T, SH, and SLH), A. jandaei (CECT 4228^T), A. hydrophila (CECT 839^T), and A. salmonicida (CECT 894^T). The scale represents S_D values converted to percentages. A final letter A in the strain designation indicates that it was recovered from ADA medium, and T indicates tergitol. Superscript “a” indicates a strain selected for 16S rDNA sequencing. Superscript “b” indicates an isolate from water leaving the drinking water treatment plant.

FIG. 2.

The phylogenetic tree of the 16S rRNA gene sequences of the Spanish strains (2238A, 2424A, and 3037T) and described Aeromonas species. The unrooted phylogenetic tree was drawn from 1,503 bp of the gene, using the neighbor-joining method in MEGA software. Numbers in parentheses are the GenBank sequence accession numbers.