Unusual Localization of an Emergent Bacterium, Raoultella ornithinolytica

A rare case of multi-drug resistant Raoultella ornithinolytica-induced sepsis in a healthy young man in Uganda

Key Clinical Message

Antimicrobial resistance (AMR) is a public health challenge. It causes unresponsiveness to treatment with antimicrobials, leads to sepsis, septic shock, and increased hospital mortality. This is compounded by new multidrug resistant organisms. We present and discuss a case of sepsis caused by a rare multi-drug resistant bacterium Raoultella ornithinolytica.

Abstract

Antimicrobial resistance is a major public health concern worldwide, associated with nearly 5 million deaths. The highest mortality attributed to AMR is seen in sub-Saharan Africa. Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa contribute to most deaths attributed to AMR globally. However, other uncommon microorganisms have been implicated. Few cases of resistant, extended-spectrum beta-lactamase (ESBL) producing Raoultella ornithinolytica have been reported to cause sepsis worldwide. To our knowledge, no case of R. ornithinolytica-induced sepsis has been reported in our settings. We report a case of sepsis due to R. ornithinolytica in an injured young adult. We received a 36-year-old man, a professional banker involved in a road traffic accident 2 h before admission. He sustained a deep degloving wound on the right ankle with exposure of the lateral malleolus and presented with severe pain, and bleeding at the injury site. x-Rays confirmed a comminuted intra-articular distal tibia and fibular fracture. Surgical debridement and external fixation were aseptically done on the same day. Below knee amputation was done on the 7th day post-admission due to extensively injured and infected limb with sepsis. Local pus culture isolated ESBL-positive R. ornithinolytica susceptible only to meropenem, ciprofloxacin, and amikacin. Introducing these antibiotics on the 11th post-admission day averted sepsis and enhanced patient recovery. With the threat of AMR, newly emerging highly resistant microbes should be expected and suspected. Early recognition of sepsis and its focus and precise intervention with antimicrobials guided by specimen culture and susceptibility profile is highly recommended and should be standard practice. It highly reduces morbidity and mortality due to sepsis.

Sepsis From Multisystem Infection With Multidrug-Resistant Raoultella ornithinolytica

Raoultella (R.) ornithinolytica is a gram-negative, encapsulated aerobe or facultative anaerobe belonging to the family Enterobacteriaceae. It is distinguished from other members in the family with a negative indole test, growth at 10^oC, production of histamine, a negative D-melezitose test, and metabolism of ornithine. R. ornithinolytica is a versatile organism found in different habitats, including soil, water, and plants, as well as colonizing the human gastrointestinal tract and throat. It was considered to cause opportunistic infection in humans but is increasingly being implicated in infections in immunocompetent individuals. Raoultella ornithinolytica causes infection in different clinical settings. Sepsis from Raoultella ornithinolytica is increasing among humans, and it is considered an emerging infectious agent in both immunocompromised and immunocompetent people. There is an increasing level of antibiotic resistance among isolates with reports of multidrug resistance.

We report the case of a 95-year-old man with multidrug-resistant R. ornithinolytica multisystem infection and review the literature.

Malignant Otitis External: Our Experience and Literature Review

BACKGROUND Malignant external otitis (MEO) is an invasive infection that can involve the external auditory canal and the skull base up to the contiguous soft tissues. Considering the changing face of MEO, we reviewed cases of MEO treated in our Ear Nose Throat (ENT) clinic - University Federico II of Naples between 2018 and 2019 to evaluate the current epidemiology of the condition and to assess the state of art on diagnosis, therapeutic and follow-up management in our patients. CASE REPORT We present the cases of three male patients with Type 2 diabetes mellitus who complained of long-lasting otorrhea and pain, with clinical suspicion of MEO. In all cases, ear swab was positive for Pseudomonas aeruginosa. All our patients received a 6-week course of intravenous ciprofloxacin, piperacillin, and tazobactam, with rapid clinical symptoms improvement and complete recovery at 1-year follow-up. CONCLUSIONS MEO is difficult to treat due to the lack of standardized care guidelines. Patients with MEO often present with severe otalgia, edema, otorrhea, and facial nerve paralysis. Clinicians must suspect MEO in elderly diabetic and immunocompromised patients with persistent otalgia after external otitis. Imaging (computed tomography and magnetic resonance imaging) can play synergistic roles in the management of MEO. To evaluate eradication of the disease, clinicians have to assess clinical symptoms and signs as well as radiological imaging and inflammatory markers.

Skull Base Fungal Osteomyelitis: A Case Report and Review of the Literature

Skull base osteomyelitis (SBO) is an invasive infection refractory to therapy, closely linked with malignant otitis externa (MOE). It is characterized by a mild clinical presentation that can delay cross-sectional imaging considered as the key to revealing it. Skull base osteomyelitis typically affects elderly diabetics and immunocompromised patients (>70 years). It most commonly has an otogenic origin due to an extension of MOE. The prognosis can be very poor without the administration of adequate and timely therapy at an early disease stage. Nowadays, Pseudomonas aeruginosa remains the most common pathogen associated with SBO. Fungi are a rare cause of MOE. This report documents a rare case of otogenic SBO caused by Candida parapsilosis in a diabetic patient, with persistent otologic symptoms as clinical onset and resistance to medical treatment. Fungal MOE has more subtle symptoms and is more aggressive than its bacterial counterpart. When MOE is resistant to antibacterial drugs, this should raise the suspicion of a fungal etiology of MOE. The current guidelines do not exhaustively describe the diagnosis, antifungal drugs of choice, and optimum duration of treatment. The description of these rare clinical cases should help with the multidisciplinary management of this disease in order to optimize the diagnosis and therapeutic protocol.