Microbiology and Risk Factors for Community-Acquired Pneumonia

Abstract

The outcome of community-acquired pneumonia (CAP) depends on the interaction between the infectious agent and the host response. Nowadays the etiology of CAP can be established in ~60% of the cases, and Streptococcus pneumoniae remains the main etiological agent in outpatients, those hospitalized, or those requiring intensive care unit (ICU) admission. Recently, the development of nucleic acid amplification techniques has emphasized the role of viruses as important etiological agents in CAP. However, some demographic factors and comorbidities will determine a higher risk of pneumonia. Thus elderly patients or those with toxic habits (smoking, alcohol abuse), and the presence of various comorbidities (respiratory, metabolic, or renal) favor the development of pneumonia by altering the inflammatory response to infection.Some medications like inhaled corticosteroids could play a role in CAP development in chronic obstructive pulmonary disease (COPD) patients. Fortunately some of these risk factors are preventable and modifiable, for example, through smoking cessation and pneumococcal and influenza vaccinations, which are the biggest successes.

Adherence to SATS antibiotic recommendations in patients with community acquired pneumonia in Johannesburg, South Africa

“…Of these microorganisms the most common isolate was Streptococcus pneumoniae (representing 58.3% of the isolates, and being documented in 61.8% of the patients). The previous study from South Africa identified 113 isolates in their 182 study patients and of these 50% were S. pneumoniae [7] The findings of both these studies that the pneumococcus was the most common isolate is compatible with what has been documented in most studies throughout the world, even among HIV-seropositive individuals [15]. There are a number of reasons for the significant differences in the frequency with which microorganisms were isolated in the two South African studies.…”

“…The earlier study was a prospective study in which a concerted effort was made to document the microbial aetiology, whereas the current study was retrospective, relied purely on patient records for isolate documentation, and the extent of the microbial workup had been decided upon by the treating clinician rather than the study investigators. Furthermore, the earlier study was restricted to severely ill cases in whom microorganisms are more commonly isolated than among general CAP patients, and particularly less severely ill cases, such as was the case in the current study [2,7,15].…”

Distribution and Antimicrobial Resistance of Streptococcus pneumoniae at Four University Hospitals in Busan and Gyeongnam

“…의 가장 중요한 원인 균으로 [1,2], 특히 침습성 폐렴알균 감염 의 경우 영유아, 노인, 만성 질환자 및 면역 저하자에게 매우 치명적인 결과를 야기할 수 있다 [3][4][5][6]. 폐렴알균의 항균제 내성 은 1980년대 이후 꾸준히 증가하였고 다제내성 폐렴알균이 세 계적으로 확산된 것으로 보고되었다 [7,8].…”

Review: Current and new generation pneumococcal vaccines

“…10 With regard to all-cause CAP, it is clear that the pneumococcus is the most commonly isolated pathogen, irrespective of whether the infection is either mild enough to be treated at home or requires hospitalisation or even intensive care unit admission, also irrespective of the severity of infection such as assessed by the Pneumonia Severity Index (PSI). 8,11 However, in a meta-analysis of studies from Europe it is clear that there are regional differences in the prevalence of the pneumococcus as a cause of CAP, depending on both the treatment setting and diagnostic approach. 12 However, since the pneumococcus is the most important pathogen in most situations, the data on the epidemiology of CAP to a large extent mirrors that of pneumococcal pneumonia.…”