CP 3 - Fatal Aeromonas hydrophila bacteraemia following floodwater exposure – A case report

Balasooriya A¹, De Silva AKL¹, Thadshaini G¹, Karunarathne M², Janaka KVC¹, Jayatilleke K¹ , ¹Sri Jayewardenepura General Hospital, Nugegoda, Sri Lanka, ²National Institute of Infectious Diseases, Sri Lanka

Abstract

Introduction

Aeromonas hydrophila is a Gram-negative bacillus ubiquitous in fresh and brackish water environments. It is a recognized cause of human infections worldwide. It is linked to aquaculture, ornamental fish and contaminated food. The true burden is underestimated due to diagnostic dilemmas and lack of structured surveillance. In Sri Lanka, despite ecological prevalence in aquaculture, no published literature on human infections exists.

Case Report

An eighty‑year‑old woman, previously healthy and independent in all activities of daily living (DALY) presented with fever and backache. She was later diagnosed with meningitis with symptoms such as neck stiffness and altered level of consciousness and based on cerebrospinal fluid (CSF) analysis with lymphocytes 10/cumm and polymorphs 5/cumm, although the CSF culture remained negative. Blood culture yielded Aeromonas hydrophila sensitive to cefuroxime, ceftriaxone, cefepime, amikacin, gentamicin, ciprofloxacin, trimethoprim- sulfamethoxazole resistant to piperacillin-tazobactam, meropenem, and imipenem. The patient had been exposed to floodwater barefoot during Cyclone “Ditwah” two weeks prior and had received a single dose of doxycycline post exposure, for leptospirosis prophylaxis. She was started on high-dose intravenous ceftriaxone empirically for meningitis and was continued for fourteen days and was discharged after clinical improvement, although back pain persisted for which she did not undergo imaging. The Echocardiogram was normal. Three weeks later, she was re-admitted with septic shock and cellulitis at a previous cannula site and repeat blood culture yielded Aeromonas hydrophila. VITEK 2 analysis showed that the initial isolate was sensitive to ceftriaxone, while the subsequent isolate was resistant. There was a delay in culture identification due to resource‑poor settings. Despite escalation to meropenem and ciprofloxacin, the patient succumbed to sepsis within three days of re-admission.

Discussion

Aeromonas should be considered a possible pathogen following floodwater exposure. Re-admission in this case raises the suspicion of an unrecognized spinal focus or secondary seeding or inadequacy of initial treatment. In lower-middle-income countries, delays in identifying Aeromonas hydrophila is a challenge due to resource limitations. Resistance due to metallo‑β‑lactamase and inducible Amp C cephalosporinase possibly resulted in developing resistance to carbapenems and cefuroxime, ceftriaxone which may have had an implication on treatment failure in this patient. Therefore, source identification should be prioritized in persistent infections and infection prevention measures should be strengthened to reduce cannula site infections.