Community-acquired pneumonia related to intracellular pathogens

Abstract

Community-acquired pneumonia (CAP) is associated with high rates of morbidity and mortality worldwide; the annual incidence of CAP among adults in Europe has ranged from 1.5 to 1.7 per 1000 population. Intracellular bacteria are common causes of CAP. However, there is considerable variation in the reported incidence between countries and change over time. The intracellular pathogens that are well established as causes of pneumonia are Legionella pneumophila, Mycoplasma pneumoniae, Chlamydophila pneumoniae, Chlamydophila psittaci, and Coxiella burnetii. Since it is known that antibiotic treatment for severe CAP is empiric and includes coverage of typical and atypical pathogens, microbiological diagnosis bears an important relationship to prognosis of pneumonia. Factors such as adequacy of initial antibiotic or early de-escalation of therapy are important variables associated with outcomes, especially in severe cases. Intracellular pathogens sometimes appear to cause more severe disease with respiratory failure and multisystem dysfunction associated with fatal outcomes. The clinical relevance of intracellular pathogens in severe CAP has not been specifically investigated. We review the prevalence, general characteristics, and outcomes of severe CAP cases caused by intracellular pathogens.

Microbial Etiology of Pneumonia: Epidemiology, Diagnosis and Resistance Patterns

“…Moreover, performing standard serologic tests on all patients with CAP is not common practice. The intracellular pathogens that are well-established as causes of CAP are: Legionella pneumophila , Mycoplasma pneumoniae , Chlamydophila pneumoniae , Chlamydophila psittaci and Coxiella burnetii [18,19]. No clinical features exist that make it possible to distinguish intracellular pathogens from classical pathogens (pneumococcus) in pneumonia, although extra-pulmonary manifestations are often associated with intracellular pathogens in CAP [20].…”

“…A recent review article [19] reported that severe CAP caused by intracellular pathogens accounts for approximately 1% to 7% of cases [6,8,21]. Since antimicrobial therapy for severe pneumonia is empiric and covers typical pathogens and the principal intracellular pathogens, results of microbiological diagnosis have an important relationship with the clinical prognosis of pneumonia.…”

Prognostic value of vitamin D in patients with pneumonia: A systematic review and meta-analysis

“…Pneumonia is a common lung disease which is responsible for significant morbidity and mortality worldwide [1,2]. Community-acquired pneumonia (CAP) is the main type of pneumonia which can also result in high risk of mortality in critically-ill patients [3][4][5].…”

Real -time PCR for early microbiological diagnosis: is it time?

“…In the adult population, acceptance of an AST intervention has also been associated with a trend toward reduced mortality on multivariable analysis. Moreover, nucleic acid amplification testing and mass spectrometry can identify selected antibiotic resistance patterns to vancomycin (VanA/ VanB), methicillin (MecA), cephalosporins (beta-lactamases) and carbapenem (CPE) [4].Polymerase chain reaction (PCR) is well established for the diagnosis of "atypical" pathogens in severe community-acquired pneumonia [6] and for the study of ARDS with possible infectious etiology, namely for respiratory viruses (HSV and CMV), with virus load quantification, and also for Pneumocystis and Aspergillus [5]. In a retrospective case-control study in adult ICU patients with pneumonia and severe sepsis or septic shock, a strategy with bronchoalveolar lavage (BAL) cultures plus BAL M-PCR led to higher microbiological yield and less time to antibiotic therapy modification compared to a BAL culture strategy (32.40 ± 14.41 vs. 41.74 ± 45.61 h; P < .001) [7].…”

“…Polymerase chain reaction (PCR) is well established for the diagnosis of "atypical" pathogens in severe community-acquired pneumonia [6] and for the study of ARDS with possible infectious etiology, namely for respiratory viruses (HSV and CMV), with virus load quantification, and also for Pneumocystis and Aspergillus [5]. In a retrospective case-control study in adult ICU patients with pneumonia and severe sepsis or septic shock, a strategy with bronchoalveolar lavage (BAL) cultures plus BAL M-PCR led to higher microbiological yield and less time to antibiotic therapy modification compared to a BAL culture strategy (32.40 ± 14.41 vs. 41.74 ± 45.61 h; P < .001) [7].…”