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Roseomonas Gilardi Bacteraemia in a Pediatric Oncology Patient on Chemotherapy: A Rare Case Report |
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Dhruv Kamlesh Mamtora, Priti Mehta, Pallavi Bhalekar 1. Consultant and Head, Department of Microbiology, S.L. Raheja, A Fortis Associate, Hospital, Mumbai, Maharashtra, India. 2. Consultant Pediatric Oncologist, Department of Pediatrics, S.L. Raheja, A Fortis Associate, Hospital, Mumbai, Maharashtra, India. 3. Microbiology Technical Supervisor, S.L. Raheja Hospital, A Fortis Associate, Mumbai, Maharashtra, India. |
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Correspondence
Address : Dr. Dhruv Kamlesh Mamtora, S.L. Raheja Hospital, A Fortis Associate, Mahim, Mumbai-400016, Maharashtra, India. E-mail: dhruv_mamtora@yahoo.com |
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ABSTRACT | |||||||||||||||||||||||
Roseomonas is a pink-pigmented, non-fermentative, gramnegative coccobacillus bacterium. Human infections caused by Roseomonas are very rare. We describe a rare case report of Roseomonas gilardi bacteraemia in a febrile, neutropenic patient on chemotherapy from oncology unit. The patient responded well to treatment given and was cured of it. | |||||||||||||||||||||||
Keywords : Blood culture, Gram negative bacteria, Neuroblastoma | |||||||||||||||||||||||
CASE REPORT | |||||||||||||||||||||||
A 10-month-old female child born of second degree consanguineous marriage presented with the chief complaints of fever on and off since 9 months. Child had history of rectovesical fistula and was operated for the same at the age of 7½ months. On clinical examination, the child weighed 7 Kg his height was 66 cm, she was well grown, with pallor and hepatosplenomegaly (3 cm each). CT-scan of chest, abdomen and pelvis revealed a 3.4 × 1.3 × 3.4 cm right paravertebral mass. CT abdomen showed liver mildly enlarged (liver span 9 cm in midclavicular line). Spleen was enlarged in size and measured 7.2 cm in size. Few subcentimeters sized lymph nodes in bilateral inguinal region, largest measuring 6 mm in short axis. NO131 I –MIBG avidity in CT demonstrated right paravertebral mass. Histopathology was suggestive of Schwannian stroma poor undifferentiated neuroblastoma, low MKI index, and unfavorable histology according to INPC classification. MYNC gene amplification was negative. Bone marrow aspiration and biopsy was uninvolved. Hemoglobin electrophoresis of both parents was normal. The child’s tumor was staged as stage II and started on COG protocol after parent’s consent. Post each chemotherapy cycle the child developed febrile neutropenia with positive blood cultures. First time the blood culture grew MRSA (Methicillin resistant Staphylococcus aureus) which was successfully treated. Post 2nd chemotherapy cycle the child developed febrile neutropenia again. CBC was hemoglobin 9.8 gm/dl, WBC 7500 with neutrophils 52% and platelets 330,000. Blood culture this time grew an unusual organism known as Roseomonas gilardi. Roseomonas gilardi is a pink pigmented gram negative bacteria that has occasionally been isolated from various clinical samples. The cultures were sent by automated blood culture. The gram stain smear of blood culture broth showed gram negative bacilli. Subcultures were done on Columbia sheep blood agar and McConkey’s agar as per protocol. After incubation for 24 hours the cultures showed no growth, however after 48 hours of incubation at 37°C, pink pigmented colonies grew on CBA [Table/Fig-1,2]. On McConkey’s agar, the growth was scanty and took around 72 hours of incubation. Catalase test was positive, and oxidase test was delayed. Organism was non fermentor. On Triple Sugar Iron agar (TSI) and the VITEK 2 Gram negative identification card was identified as Roseomonas gilardi with 99% probability and excellent identification. The isolate was susceptible to ampicillin, amoxicillin-clavulenic acid, cefoperazone, gentamicin, tobramycin, amikacin, ciprofloxacin, tetracycline, aztreonam, imipenem and meropenem. It was resistant to cefuroxime, ceftriaxone, ceftazidime and trimethoprim/sulfamethoxazole. The patient responded to treatment with IV amoxycillin clavulanic acid and amikacin as per culture sensitivity reports after obtaining reports for 14 days. The counts normalized, all acute prognostic markers (CRP) levels came down and patient was discharged. Patient had completed chemotherapy on 17th February 2016 and is in remission with monthly follow-up. | |||||||||||||||||||||||
DISCUSSION | |||||||||||||||||||||||
In 1984, a new group of unnamed pink-pigmented non fermentative bacteria that phenotypically resembled Methylobacterium extorquens (Pseudomonas mesophilica) was described by Gilardi and Faur (1). “Pink coccoid” group was term coined by the Centers for Disease Control and Prevention (CDC) to refer to this collection of phenotypically related organisms (2). The genus Roseomonas was named in 1993 by Rihs et al., on the basis of DNA hybridization of pink pigmented gram negative bacteria (3). This genus includes Roseomonas gilardi, Roseomonas cervicalis, Roseomonas fauriae (Roseomonas genomospecies 1, 2 and 3 respectively) and 3 unnamed Roseomonas genomospecies 4, 5 and 6. They have been isolated from the aquatic environment. The organism have been isolated from blood, wound, urinary and respiratory specimens, peritoneal dialysis fluid, corneal scrapings and bones [4,5]. The genus Roseomonas has been recently established hence clinical experience with infection caused by these organisms is relatively limited. Though, Roseomonas sp. appears to have low pathogenic potential, some species may cause clinically significant or even fatal disease in immunocompromised patients like those with leukemia, septicemia, cancer chemotherapy and dialysis [5-7]. Present case is in accordance with previous case reports wherein the patients were immuno-compromised and the patient was child with poorly differentiated neuroblastoma on cancer chemotherapy. Srifuengfung S et al., described first case from Thailand (8). First case report of allogenic hematopoietic stem cell transplant associated Roseomonas infection was reported from Saudi Arabia (9). In India, case report of community acquired Roseomonas was reported from lung cavities affected by tuberculosis (10). This is a rare case from India and in pediatric oncology which correlates well with previously published case reports from western countries and a few amongst Asian countries. | |||||||||||||||||||||||
CONCLUSION | |||||||||||||||||||||||
The case report on Roseomonas gilardi causing bacteraemia is rare from Indian subcontinent. Potential clinical significance of pink pigmented, gram negative coccoid, oxidase – positive microorganisms should be known to clinicians, particularly when isolated from blood culture of patients with immunocompromised condition. Also important is case based discussion between oncologist and microbiologist and timely appropriate treatment based on antibiotic susceptibility pattern. | |||||||||||||||||||||||
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