Review began 07/06/2022 Review ended 07/26/2022 Published 07/28/2022 © Copyright 2022 Fadlallah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC- BY 4.0., which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Chryseobacterium indologenes Ventilator- Associated Pneumonia in an Elderly Patient: A Case Report Mahdi M. Fadlallah , Darine M. Kharroubi , Zeinab Zeineddine , Sarah M. Salman 1. Department of Laboratory Medicine, Al-Zahraa Hospital University Medical Center, Beirut, LBN 2. Department of Laboratory Medicine, Lebanese University, Faculty of Medical Sciences, Beirut, LBN Corresponding author: Sarah M. Salman, salman.sara@hotmail.com Abstract Chryseobacterium indologenes is a rare non-fermenting gram-negative pathogen that can cause opportunistic infections in humans. Most infections are nosocomial and acquired through contaminated devices such as ventilators, endotracheal tubes, and indwelling catheters. An increasing number of infections have been reported in recent years after the first reported case of ventilator-associated pneumonia in 1993. Blood, lung, ocular, and peritoneal infections, among others, have been reported. The high rate of intrinsic resistance to broad-spectrum antibiotics is a matter of concern since there are no standard guidelines for the management and treatment of this infection. Here, we present the case of a 94-year-old female who was admitted and intubated after a cerebral vascular accident. During her stay, she developed a fever. The deep tracheal aspirate culture was positive for gram-negative bacilli with smooth, circular, and yellow-pigmented colonies that were later identified as C. indologenes. Antimicrobial susceptibility tests done with VITEK 2 and by the Kirby-Bauer disc diffusion method showed susceptibility to ciprofloxacin, minocycline, and trimethoprim-sulfamethoxazole and resistance to all other tested antimicrobials. The infection was successfully treated with ciprofloxacin antibiotic. To the best of our knowledge, this is the first reported case of C. indologenes infection in Lebanon. Categories: Internal Medicine, Infectious Disease, Pulmonology Keywords: multidrug-resistant bacteria, tracheal aspirate, ventilator-associated pneumonia, elderly, healthcare- associated infection, c. indologenes Introduction Chryseobacterium indologenes (C. indologenes) (known in the past as Flavobacterium indologenes) belong to the Flavobacterium species CDC group IIb [1]. It is a non-motile, oxidase-positive, catalase-positive, non- fermenting gram-negative pathogen that can cause opportunistic infections in humans [2,3]. Although ubiquitous in nature, this organism is a rare pathogen and normally non-existing in the human microflora [1,4]. Mostly, C. Indologenes infections are nosocomial [5]. Despite C. indologenes having low virulence, it can be a life-threatening pathogen causing significant morbidity and mortality among patients with predisposing conditions such as extremes of age, prolonged antibiotic therapy, recent surgery, immunodeficiency, malignancies, presence of invasive devices, and indwelling catheters [6]. Choice of antibiotic therapy for the treatment of C. indologenes infections is difficult due to the unpredictability and the rapid evolution of its antimicrobial resistance. It is often resistant to many antimicrobial agents used for the empiric treatment of gram-negative infections [4]. In the present manuscript, we report a rare case of C. indologenes pneumonia in an elderly patient on mechanical ventilation. Case Presentation A 94-year-old female known to have hypertension and coronary artery disease presented to the emergency department with symptoms of decreased level of consciousness and right-sided weakness. Clinical examination on arrival at our facility showed raised blood pressure (170/80 mmHg), tachycardia (143/min), normal body temperature (36.8℃), oxygen saturation (SpO 2 ) of 96%, and Glasgow Coma Scale of 7. Consequently, emergent intubation of the patient was performed. A neurological exam revealed a neurological deficit in terms of weakness in the right arm and leg. MRI results showed acute cerebral ischemia in the left middle cerebral artery territory. Laboratory tests revealed polymorphonuclear leukocytosis (White blood count: 19.6×10 3 /µL, neutrophils: 18×10 3 /µL), normal hemoglobin (13 g/dL), and platelet count (184×10 3 /µL), raised acute phase reactants (C-reactive protein 397 mg/L), and numerous leukocytes in urine (Table 1). Urine culture was taken and broad-spectrum antibiotics, ceftriaxone 2 g intravenous (IV) once daily, and piperacillin/tazobactam 4.5 g IV every 6 hours were started. The patient was admitted to the intensive care unit (ICU) for management of her cerebrospinal vascular insult. Urine culture was positive after 48 hours for Escherichia coli (>10 5 CFU/mL) which was sensitive to both antibiotics already 1, 2 1, 2 1, 2 1, 2 Open Access Case Report DOI: 10.7759/cureus.27426 How to cite this article Fadlallah M M, Kharroubi D M, Zeineddine Z, et al. (July 28, 2022) Chryseobacterium indologenes Ventilator-Associated Pneumonia in an Elderly Patient: A Case Report. Cureus 14(7): e27426. DOI 10.7759/cureus.27426