Title: Multiple Brain Abscesses Caused by Pseudomonas luteola
Abstract: To the Editors: A 3-year-old male child presented with coughing and fever in August 2008. Two years before (in 2006), he suffered from traumatic biliary tract dissection. He was treated by external biliary tract drainage for 1 month, 2 weeks of broad spectrum antibacterial agents; He recovered without sequelae. He was treated with a 1-week course of oral amoxicillin/clavulanic acid. Serum C-reactive protein was 36 mg/L (normal, <6 mg/L) and fibrinogen was 7.8 g/L (normal, <4 g/L). Physical examination was unremarkable except for low-grade fever. The patient was discharged home. Ten days later, he was readmitted because of neck stiffness. The cerebrospinal fluid analysis revealed 990 white blood cells/mm3 (67% neutrophils) and 17 erythrocytes/mm3. Glucose was 1.6 mmol/L and protein was 1.7 g/L. Gram staining and culture of the cerebrospinal fluid on appropriate media were negative. Serum C-reactive protein was 79.1 mg/L. White blood cell count was 15.1 109/L, with 10.8 109neutrophils/L. Three sets of blood cultures drawn at admission remained sterile. Intravenous cefotaxime 200 mg/kg per day was initiated and the patient was transferred to the Pediatric Intensive Care Unit at the University Hospital of Rennes (France). A computed tomography of the brain (CT-scan) revealed bilateral multifocal abscesses predominant on the right, the largest measuring 35 mm in diameter, confirmed by magnetic resonance imaging (Fig. 1). Chest radiograph showed infiltrates in the upper left field. Otoscopic and rhinoscopic examinations, echocardiographic evaluation for congenital heart disease or endocarditis were normal. Serological tests for HIV, CMV, hepatitis A, B, and C, aspergillosis, toxoplasmosis, cryptococcosis, trichinosis, hypodermosis, toxocariasis, and hydatidosis were negative. The diagnosis of tuberculosis was excluded.FIGURE 1.: Magnetic resonance imaging (MRI) of the multiple brain abscesses (August 2008). Axial T1 sequence with gadolinium.Twelve days later, the child was sleepy and developed left mydriasis with depressed consciousness. Brain computed tomography revealed enlargement of abscesses with left ventricular dilatation. External ventricular drainage was done. Treatment included cefotaxime, metronidazole 30 mg/kg per day, fosfomycin 200 mg/kg per day, and phenobarbital (5 mg/kg per day). Stereotactic aspiration of the brain abscesses revealed the presence of Pseudomonasluteola by bacteriologic cultures and by 16SrDNA gene amplification of the sample. Antibiotic treatment was to metronidazole (as previously), ciprofloxacin 25 mg/kg per day, and meropenem 500 mg 3 times a day, for 90 days. The clinical outcome was marked by right hemiparesis, blindness, swallowing disorder, and epilepsy. The patient was feverish during 4 months despite the reassuring clinical evolution (CRP decrease and sterilization of bacteriologic samples). During the pediatric intensive care unit hospitalization, severe hyponatremia was observed due to a cerebral salt wasting syndrome and hepatic cytolysis. Treatment with ursodeoxycholic acid was used and the child recovered when antibiotics were stopped. The fever persisted for another week. The boy had 6 new neurosurgeries; twice for external ventricular bypasses, once for stereotactic aspiration, once for partial temporal lobectomy, and twice for peritoneal ventricular shunts. Two preoperative samples from lobectomy showed growth of P. luteola. The child was hospitalized for 5 1/2 months, and he is now almost self-sufficient: he can walk and eat alone, he has no swallowing disorder, but he has incontinence and sight disorders. All blood cultures remained sterile and P. luteola was isolated from 3 preoperative samples of the brain abscesses. The strain was first isolated after a 48-hour incubation period on trypticase soy agar at 37°C, but in the 2 further samples culture enrichment was necessary to isolate the strain. The microorganism was identified using a 32GN gallery (Biomérieux Marcy l'Etoile, France), and the identification was confirmed by sequencing the 16S rDNA gene. This isolate was susceptible to aminoglycosides, fluoroquinolones (ciprofloxacin, pefloxacin), cotrimoxazole, aminopenicillin, carboxypenicillin, ureidopenicillin, imipenem, and meropenem but exhibited resistance to some cephalosporins (cephalothin, cefoxitin, cefamandole, cefotaxime). Minimal inhibitory concentration determinations were confirmed by the E-test method (AB Biodisk, AES Laboratoires, Bruz, France), and minimal inhibitory concentration values were 0.047 μg/mL and 0.047 μg/mL for ciprofloxacin and meropenem, respectively. P. luteola was originally named P. luteola then subsequently reclassified as Centers for Disease Control and Prevention group Ve-1 and Chryseomonas luteola, but 16S rDNA sequence analysis suggested that genus names Chryseomonas, Flavimonas, and Pseudomonas were synonymous. P. luteola are environmental bacteria, ubiquitous in water and soil, rarely described as a human pathogen. Most cases reported to date were bloodstream infections associated with prosthetic valve endocarditis, complicated cardiac surgery, the presence of a foreign body, especially central venous access, joint prosthesis, pancreatitis complicated by pancreatic abscess, peritonitis, severe trauma, and cutaneous abscess. Rarely, nonbacteremic cases have been described: postneurosurgical infections, fatal meningitis in a newborn, peritonitis complicating gangrenous appendicitis or continuous ambulatory peritoneal dialysis, femur abscess, subphrenic abscess, chronic postoperative endophthalmitis, facial cellulitis, leg ulcer in a patient with sickle cell disease, and hand infection.1 Pseudomonas species are rarely reported in brain abscess. Gupta et al2 reviewed 80 cases of brain abscesses with 7 cases caused by Pseudomonas. In these cases the mortality was high (57%) and was associated with a high rate of resistance to antibiotics. Pseudomonas aeruginosa brain abscess have been reported in children with middle ear infection, sinusitis, ethmoiditis, or conjunctivitis particularly in epidemic neonatal care unit cases.3 Nosocomial postneurosurgical procedure infections have also been described. Stephanov and Sidani4 reported a case of a 60-year-old woman with a brain abscess caused by a nonfermenting aerobic bacillus Brevundimonas vesicularis (formerly named Pseudomonasvesicularis). Yee-Guardino et al5 reported a nosocomially acquired brain abscess in a child caused by Pseudomonasstutzeri. Surgical abscess drainage associated with antimicrobial broad spectrum therapy is the treatment of choice for most brain abscesses. Empirical treatment recommendations are mainly based on risk factors. Broad spectrum agents such as third generation cephalosporin and metronidazole are frequently the first line choice for immunocompetent patients. This empirical treatment is not suitable for Pseudomonas species and needs to be revaluated as soon as microbiological results are available. ACKNOWLEDGMENTS The authors thank Philippe Gautier for his technical assistance. Anne Gaschet, PD Pôle Microorganismes, Teaching Hospital CHU Pontchaillou Equipe Microbiologie Faculté des Sciences Pharmaceutiques et Biologiques Université de Rennes 1, Université Européenne de Bretagne Caroline Piau, PS Jérémie Violette, PS Pôle Microorganismes, Teaching Hospital CHU Pontchaillou Pierre-Yves Donnio, PhD Anne Jolivet-Gougeon, PhD Pôle Microorganismes, Teaching Hospital CHU Pontchaillou Equipe Microbiologie Faculté des Sciences Pharmaceutiques et Biologiques Université de Rennes 1, Université Européenne de Bretagne Charlotte Engrand, MD Pierre Bétrémieux, PhD Patrick Pladys, PhD Departments of Pediatrics Neonatal Intensive Care Unit University Hospital Pierre Tattevin, PhD Infectious Diseases and Intensive Care Unit Pontchaillou University Hospital Rennes, France