A Case of Aeromonas trota in an Immunocompromised Patient with Diarrhea

Abstract

According to recent literature, 95.4% of the <i>Aeromonas</i> strains associated with human clinical cases correspond to four species: <i>Aeromonas caviae</i>, <i>Aeromonas dhakensis</i>, <i>Aeromonas veronii</i> and <i>Aeromonas hydrophila.</i> However, other less prevalent species such as <i>Aeromonas trota,</i> are also described from clinical samples. Based on its low incidence, the latter species can be regarded as rare and it is the only <i>Aeromonas</i> species susceptible to ampicillin. From the taxonomic point of view, <i>A. trota</i> is considered a synonym of the species <i>Aeromonas enteropelogenes.</i> The objective of this study is to present a new clinical case associated with <i>A. trota</i> in order to increase the knowledge about this species<i>.</i> The strain was recovered from the feces of a 69-year-old patient with a diarrheal syndrome and peritoneal psammocarcinoma. The preliminary identification as <i>Aeromonas</i> sp. was obtained with the API 20E, but it was characterized as <i>Aeromonas jandei</i> and also as <i>Aeromonas enteropelogenes</i> with different scores with the matrix-assisted laser desorption ionization time of flight (MALDI-TOF). Based on the sequence of the <i>rpoD</i> gene, it was confirmed to be <i>A. trota</i>. The antimicrobial resistance pattern showed that the strain was susceptible to ampicillin, penicillins in combination with beta-lactamase inhibitors, quinolones, carbapenems, aminoglycosides and cephalosporins, except cephalothin. In conclusion, the recognition of an <i>Aeromonas</i> strain susceptible to ampicillin should alert the clinical microbiologist of the possible involvement of this rare species. Furthermore, the MALDI-TOF database should be updated indicating that the species <i>A. enteropelogenes</i>, is a synonym of <i>A. trota</i>.