Bacterial Meningitis Caused by Myroides in a Patient With Cerebrospinal Fluid Leakage

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To the Editor: Myroides sp are Gram-negative bacteria formerly known as Flavobacterium. This species is often found in environmental sources such as soil and water. It is rarely considered a pathogenic microorganism but rather an opportunistic bacterium that can cause clinical disease in immunocompromised individuals.1 A variety of infections that include cellulitis, bacteremia, endocarditis, and pyelonephritis has been described to date.2 Infection of the central nervous system (CNS) is extremely uncommon and has been reported only once before.3 We describe here the second case of meningitis secondary to Myroides in a patient with maxillary sinus carcinoma. A 47-year-old man presented with fever and headaches over the last 4 days. He also complained of intermittent rhinorrhea for 1 month. He had a history of poorly differentiated squamous cell carcinoma of the left maxillary sinus stage IV. He underwent Cyber knife, radiation therapy, and left maxillectomy that left him with exposed bone in posterior maxillary wall and entire sphenoid cavity. His clinical course was complicated by skull base osteomyelitis, for which he received multiple courses of intravenous antibiotics and suppressive therapy with oral trimethoprim-sulfamethoxazole (for a history of Staphylococcus aureus in bone cultures). On admission, he was febrile and mildly lethargic. Neurologic examination revealed nuchal rigidity, and Kerning and Brudzinsky signs were negative. Laboratory studies showed normal white blood cell count (8 K/μL) and low hemoglobin (8 g/dL). Head computed tomography demonstrated chronic changes consistent with osteomyelitis of the clivus, sphenoid bone, ethmoid, and maxillary sinuses. It also revealed extensive pneumocephalus suspicious for rent in the cribriform plate. Given the high suspicion for meningitis, a lumbar puncture was performed on the day of admission. The cerebrospinal fluid (CSF) analysis showed 89 white blood cells per millimeter3 with lymphocytic predominance (81%), high protein (84 g/dL), and low glucose (45 mg/dL). Gram stain was negative. Blood cultures were also drawn. Analysis of the fluid leaking from nares was positive for β-2 transferrin, which is marker for CSF. These findings were indicative of cerebrospinal leakage that possibly led to meningitis. The patient was on trimethoprim-sulfamethoxazole on admission, which was discontinued, and he was started on acyclovir, cefepime, and vancomycin empirically. On hospital day 3, he was taken to the operating room and underwent placement of pericranial vascularized flap for repair of skull base defect. On hospital day 4, CSF cultures grew Gram-negative rods that were further identified as Myroides sp by matrix-assisted laser desorption ionization time of flight. Susceptibility testing was performed by Vitek 2 (BioMerieux) and interpreted as per Clinical and Laboratory Standards Institute 2014 guidelines. The isolate showed resistance to amikacin, ceftazidime, gentamicin, and tobramycin (Table 1). Blood cultures did not show any growth. Acyclovir, cefepime, and vancomycin were discontinued, and he was started on meropenem. His clinical status improved over the following days. Lumbar puncture was repeated on hospital day 10, and CSF showed normalization of parameters and negative culture. The patient was discharged in stable condition to complete 3 weeks of treatment with meropenem.TABLE 1: Antibiogram of Myroides spMyroides sp is considered an unusual pathogen, but it is being increasingly described in different clinical settings. A recent review by Beharrysingh et al2 identified 48 cases, most of them occurring in immunocompromised hosts. The only case of CNS infection was reported by Macfarlane et al3 and occurred in a 6-week-old infant who developed hydrocephalus and ventriculitis. It remains unknown how this organism gained access to the CNS on that patient; however, the authors hypothesized that this bacterium could have been introduced into the CSF by repeated sampling of the ventricles.3 Our patient presented CSF leakage, which put him at higher risk to develop meningitis.4 Of note, he was on suppressive antibiotics for chronic osteomyelitis, which probably contributed to nasopharynx colonization by uncommon and resistant organisms such as Myroides sp. The treatment of Myroides is challenging because most strains express resistance to a great variety of antibiotics including β-lactams and aminoglycosides.5 Fluoroquinolones seem to be a good therapeutic option. Fortunately, in our case, the susceptibility testing only showed resistance to aminoglycosides and ceftazidime, and treatment with meropenem led to a favorable outcome. Our case illustrates the pathogenic role of Myroides in patients with CSF leakage. We believe that suppressive antibiotics might favor colonization and subsequent infection by this resistant organism. Jose Armando Gonzales Zamora, MDJavier Baez Presser, MD Division of Infectious Diseases Department of Medicine Miller School of Medicine University of Miami Miami, FL [email protected]