ObjectivesTo study the pathogenic bacterial profile and drug resistance in older patients with community-acquired pneumonia (CAP) in outpatients with fever, and provide evidence to diagnose and treat CAP timely and accurately.MethodsWe studied older (>60 years) patients with CAP in Beijing Shijitan Hospital from 2016 to 2017. Pathogenic bacteria from sputum of patients were isolated and identified and their resistance to antibiotics was tested. Risk factors for multidrug-resistant CAP (MDR-CAP) and clinical outcomes were analyzed.ResultsA total of 5563 outpatients with fever were recruited and 391 had CAP. A total of 117 isolates of pathogenic bacteria were obtained from 176 CAP cases. The main pathogenic bacteria were Klebsiella pneumoniae (27.4%), Escherichia coli (17.9%), Staphylococcus aureus (12.0%), Pseudomonas aeruginosa (10.3%), and Streptococcus pneumoniae (9.4%). A drug sensitivity test (DST) showed that K. pneumoniae, E. coli, and P. aeruginosa had good sensitivity to imipenem, cefoperazone/sulbactam, piperacillin/tazobactam, and amikacin. Staphylococcus aureus and Streptococcus pneumoniae had strong sensitivity to vancomycin, linezolid, and levofloxacin. Previous multiple antibiotic treatment was an independent risk factor for MDR-CAP.ConclusionsGram-negative bacteria are the main pathogenic bacteria in older patients with CAP. Identification and DSTs of pathogens could enable accurate diagnosis and treatment of CAP.

The purpose of this study was to analyze the incidence, etiology and clinical characteristics of community-acquired pneumonia (CAP) among outpatients with sore throat and/or cough, and thus to provide theoretical basis for timely and accurate diagnosis and treatment for CAP. We used chest X-rays for fever (a temperature greater than 37.5°C) patients, who were recruited since 2007, presenting with sore throat and/or cough. The patients' age, gender, days of fever, respiratory symptoms (e.g. cough and sputum), peripheral blood count and etiology (pathogens) of CAP were recorded. Of all the 6539 fever outpatients, those aged 10-39 and above 60 years old accounted for 61.0% and 15.6%, respectively. In total, 402 were diagnosed with CAP with an incidence rate of 6.1%. Among them, 38.1% were above 60 years old. The prevalence increased with age. Of the 402 CAP patients, 36.8% (148/402) presented no respiratory symptoms and 30.1% (121/402) had positive etiology. The top three pathogens were Mycoplasma pneumoniae (23.1%), Streptococcus pneumoniae (17.3%) and Haemophilus influenzae (9.1%). Among the 121 etiology-positive patients, 14 cases were mixed infections (at least one atypical pathogen). Nine cases were M. pneumoniae mixed with bacterial/virus infection, and five cases were Chlamydia pneumoniae mixed with other bacteria/mycoplasma infection. We found that fever outpatients have a higher prevalence of CAP, which increases with age, i.e. older people are more susceptible to CAP. S. pneumoniae and H. influenzae are common pathogens in CAP; however, atypical pathogens, especially M. pneumoniae, remain the most common pathogens in CAP.