Unmasking The Unusual Respiratory Pathogen: Kerstersia gyiorum

Abstract

Background
Kerstersia gyiorum is a rare gram-negative, oxidase-negative, non-fermenting coccobacillus belonging to the family Alcaligenaceae. Human infection with this organism is uncommon, and respiratory isolation has been only rarely described. We report a case of acute infective exacerbation in a patient with chronic bronchiectasis in whom K.gyiorum was identified from respiratory specimens, representing one of the rare cases from India.
Case report
A 44-year-old woman with long-standing cough, wheeze, exertional dyspnea, and recurrent rhinosinusitis presented with worsening respiratory symptoms. Evaluation revealed grade III clubbing, bilateral crepitations and rhonchi, peripheral edema, elevated jugular venous pressure, loud P2, and tricuspid regurgitation murmur. High-resolution computed tomography of the thorax demonstrated bilateral cystic and cicatricial bronchiectasis with centrilobular nodules and tree-in-bud opacities. She was initially managed as bilateral bronchiectasis with obstructive airway disease, cor pulmonale, and severe pulmonary hypertension, but required readmission after clinical deterioration. Laboratory findings showed neutrophilic leukocytosis, elevated C-reactive protein, and raised NTproBNP. Chest radiography demonstrated bilateral hyperinflation with patchy non-homogenous opacities. Sputum and bronchoalveolar lavage cultures yielded moderate growth of gram-negative bacilli identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as K.gyiorum . The isolate was susceptible to amikacin, gentamicin, ceftriaxone, ceftazidime and ciprofloxacin. Mycobacterial and fungal cultures were negative. During the course of hospital stay she
developed type 2 respiratory failure requiring non-invasive ventilation. Bronchoscopy was done which showed mucopurulent secretions in both bronchial trees. Treatment with intravenous ceftriaxone, azithromycin, bronchodilators, mucolytics and diuretics was started. Supportive care was continued. These measures led to gradual improvement and she was eventually discharged from
hospital in stable condition.
Conclusion
This case highlights the need to keep K.gyiorum in the list of potential and emerging opportunistic respiratory pathogen in patients with chronic structural lung diseases. Identification of these organisms by advanced microbiological techniques is essential for early diagnosis and targeted antimicrobial therapy.