Pseudomonas otitidis bacteremia in an immunocompromised patient with cellulitis: case report and literature review

• Published in: BMC infectious diseases Vol. 23; no. 1; p. 883
• Main Authors: Mori, Takeo, Yoshizawa, Sadako, Yamada, Kageto, Sato, Takahiro, Sasaki, Masakazu, Nakamura, Yusuke, Gen, Ukyo, Murakami, Hinako, Kashiwagi, Katsuhito, Maeda, Tadashi, Miyazaki, Taito, Yamaguchi, Tetsuo, Urita, Yoshihisa, Ishii, Yoshikazu, Tateda, Kazuhiro
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 18.12.2023; BioMed Central; BMC
• Subjects: Antibacterial agents; Antibiotics; Antimicrobial agents; Bacteremia; Bacterial infections; Beta lactamases; Blood; Blood culture; Cancer; Carbapenems; Care and treatment; Case Report; Case reports; Cefepime; Cell culture; Cellulitis; Cephalosporins; Chemotherapy; Complications and side effects; Dosage and administration; Edema; Gram-negative bacilli; Health aspects; Identification; Immunocompromised host; Immunocompromised hosts; Immunocompromised patient; Infections; Ionization; Levofloxacin; Literature reviews; Mass spectrometry; Mass spectroscopy; Medical examination; Meropenem; Metallo-β-lactamase; Metallography; Multiple myeloma; Neutropenia; Pathogens; Patients; Penicillin; POM-1; Prevention; Pseudomonas; Pseudomonas aeruginosa; Pseudomonas otitidis; Risk factors; Soft tissues; Type 2 diabetes; Japan; United States > US; Case report; Cellulitis; Pseudomonas otitidis; Bacteremia; Immunocompromised patient; POM-1
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/s12879-023-08919-0

Pseudomonas otitidis belongs to the genus Pseudomonas and causes various infections, including ear, skin, and soft tissue infections. P. otitidis has a unique susceptibility profile, being susceptible to penicillins and cephalosporins but resistant to carbapenems, due to the production of the metallo-β-lactamase called POM-1. This revealed genetic similarities with Pseudomonas aeruginosa, which can sometimes lead to misidentification. We report the case of a 70-year-old Japanese male who developed cellulitis and bacteremia during chemotherapy for multiple myeloma. He was initially treated with meropenem, but blood culture later revealed gram-negative bacilli identified as P. otitidis using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Carbapenem resistance was predicted from previous reports; therefore, we switched to dual therapy with levofloxacin and cefepime, and favorable treatment results were obtained. This is the first reported case of P. otitidis cellulitis and bacteremia in an immunocompromised patient. Carbapenems are typically used in immunocompromised patients and P. otitidis is often resistant to it. However, its biochemical properties are similar to those of Pseudomonas aeruginosa; therefore, its accurate identification is critical. In the present study, we rapidly identified P. otitidis using MALDI-TOF MS and switched from carbapenems to an appropriate antimicrobial therapy, resulting in a successful outcome.