Chlamydia pneumoniae-associated pleuropericarditis: a case report and systematic review of the literature

Background Chlamydia pneumoniae is a common cause of atypical community acquired pneumonia (CAP). The diagnostic approach of chlamydial infections remains a challenge. Diagnosis of delayed chlamydial-associated complications, involving complex autoimmune pathophysiological mechanisms, is still more challenging. C. pneumoniae-related cardiac complications have been rarely reported, including cases of endocarditis, myocarditis and pericarditis. Case presentation A 40-year old female was hospitalized for pleuropericarditis following lower respiratory tract infection. The patient had been hospitalized for CAP (fever, dyspnea, chest X-ray positive for consolidation on the left upper lobe) 5 weeks ago and had received ceftriaxone and moxifloxacin. Four weeks after her discharge, the patient presented with fever, shortness of breath and pleuritic chest pain and was readmitted because of pericardial and bilateral pleural effusions (mainly left). The patient did not improve on antibiotics and sequential introduction of colchicine and methylprednisolone was performed. The patient presented impressive clinical and laboratory response. Several laboratory and clinical assessments failed to demonstrate any etiological factor for serositis. Chlamydial IgM and IgG antibodies were positive and serial measurements showed increasing kinetics for IgG. Gold standard polymerase chain reaction of respiratory tract samples was not feasible but possibly would not have provided any additional information since CAP occurred 5 weeks ago. The patient was discharged under colchicine and tapered methylprednisolone course. During regular clinic visits, she remained in good clinical condition without pericardial and pleural effusions relapse. Conclusions C. pneumoniae should be considered as possible pathogen in case of pleuritis and/or pericarditis during or after a lower respiratory tract infection. In a systematic review of the literature only five cases of C. pneumoniae associated pericarditis were identified. Exact mechanisms of cardiovascular damage have not yet been defined, yet autoimmune pathways might be implicated.

1348. A Novel Host-Protein Signature Comprising TRAIL, IP-10 and CRP Differentiates Bacterial from Viral Infection in COPD Patients with Suspected Lower Respiratory Tract Infection

Background Identifying infectious etiology is often challenging, yet essential for patient management, including antibiotic use. Studies have shown that a host signature comprising TNF-related apoptosis induced ligand (TRAIL), interferon gamma induced protein-10 (IP-10) and C-reactive protein (CRP) accurately differentiates bacterial from viral infection with negative predictive value >98%. Performance data was lacking in chronic obstructive pulmonary disease (COPD) patients with suspected lower respiratory tract infection (LRTI). Methods Adults aged >18 years with suspected LRTI were prospectively recruited at 3 medical centers (OBSERVER; grant #684589; NCT003011515). Reference standard infection etiology was adjudicated by 3 independent experts based on clinical, laboratory, microbiological, radiological and follow-up data. Host signature generates a bacterial likelihood score (0-100), providing three results: viral (0-35), equivocal (35-65) and bacterial (65-100). Experts were blinded to the signature result. Results Out of 583 adults recruited with suspected LRTI, 422 met infectious criteria, of whom 48 had a recorded history of COPD. 19 cases were adjudicated by the experts as bacterial, 14 as viral and 15 were indeterminate (Figure 1). The mean age was 68.2 years (standard deviation 12.3); 33 (68.8%) presented after two or more days of symptoms and 38 (79.2%) were hospitalized for a median of 6 days. 15 (31.2%) were female. For the patients adjudicated bacterial or viral labels (n=33), the discharge diagnoses were: COPD exacerbation, 12 cases (36.4%); pneumonia, 12 cases (36.4%) (3.0%); acute bronchitis, 2 cases (6.1%); upper RTI ,1 case; unspecified viral infection 1 case (3.0%); or other, 5 cases (15.2%). Host signature correctly classified all 19 bacterial cases and 8 of the viral cases, providing accurate etiology labels for 27/33 COPD patients with reference standard labels (81.8%). The remaining 6 viral cases received equivocal scores (18.2%). COPD patient enrollment and etiology labels in the Observer study Conclusion Host signature accurately differentiates between bacterial and viral infections in patients with COPD history, supporting potential to improve management among these patients frequently admitted for RTIs. Disclosures Michal Stein, MeMed (Employee) Meital Paz, MD, MeMed (Employee) Tanya Gottlieb, PhD, MeMed (Employee, Shareholder) Eran Barash, MA, MeMed (Employee) Roy Navon, MSc, MeMed (Employee, Shareholder) Einat Moscoviz, BSc+ MBA, MeMed (Employee) Tahel Ilan Ber, MD, MeMed (Employee, Shareholder) Liran Shani, MD, MeMed (Employee) Olga Boico, PhD, MeMed (Employee) Einav Simon, PhD, MeMed (Employee, Shareholder) Noa Avni, PhD, MeMed (Employee) Kfir Oved, MD, PhD, MeMed (Board Member, Employee, Shareholder) Eran Eden, PhD, MeMed (Board Member, Employee, Shareholder)