Shewanella spp. infections in Gran Canaria, Spain: retrospective analysis of 31 cases and a literature review

Abstract

Introduction: Shewanella spp. can cause severe skin and soft-tissue infections, gastrointestinal infections, otitis and bacteraemia, generally upon contact with seawater or consumption of raw seafood. Recently, a new condition termed 'patera foot' characterized by acute skin and soft-tissue infection has been described in irregular immigrants arriving to the Canary Islands, Spain, in rudimentary boats. Most infections are caused by a single species, Shewanella algae. The improvement of the diagnostic capabilities in clinical microbiology laboratories has resulted in a growing number of cases being reported worldwide, most of them coming from warm regions.

Case presentation: In this work, we reviewed the medical records of all the patients with Shewanella infections in the two university hospitals of Gran Canaria (the Canary Islands, Spain) during the period 2000-2016, resulting in the identification of 31 cases. We also conducted a literature review of Shewanella infections reported worldwide in recent years.

Conclusion: This case series suggests that Shewanella infections are nosocomially acquired more frequently than previously thought. In addition, the unexpectedly high proportion of multidrug-resistant isolates raises concerns.

Keywords: Shewanella; bacteremia; multidrug resistant; nosocomial; patera foot; soft-tissue infection.

Fig. 1.

Heatmap showing the antibiotic-susceptibility profile of S. algae and S. putrefaciens isolates from Gran Canaria, Spain. Strain numbers refer to case numbers in Table 1. A/C, amoxicillin/clavulanic acid; P/T, piperacillin/tazobactam; CTX, cefotaxime; CEP, cefepime; IMP, imipenem; GEN, gentamicin; TOB, tobramycin; AMK, amikacin; CIP, ciprofloxacin; MIN/TET, minocycline/tetracycline; TIG, tigecycline; T/S, trimethoprim/sulfamethoxazole. Colour code: red, resistant; orange, intermediate; green, susceptible; grey, not tested.