Community-acquired pneumonia: bacteriological profile and microbiological investigations.

c ommunity-acquired pneumonia is a disease of varied etiologies. Each case varies with many causative agents implicated. This has been attributed to regional differences in the prevalence of microorganisms. Nevertheless there are several common etiologies leading to caP in community as well as hospital settings. 1 common causative agents of pneumonia in ambulatory patients are Streptococcus pneumoniae, Mycoplasma pneumoniae, Haemophilus infuenzae, Chlamydia pneumoniae and respiratory viruses (infuenza a and B, adenovirus, respiratory syncytial virus and parainfuenza). common causes of pneumonia in hospital settings are S. pneumoniae, M. pneumoniae, H. infuenzae, C. pneumoniae, Legionella spp. aspiration respiratory viruses (infuenza a and B, adenovirus, respiratory syncytial virus and parainfuenza). 2 common causes of severe pneumonia are S. pneumoniae, Staphylococcus aureus, Legionella spp. Gram-negative bacilli and H. infuenzae. Literature Review fang et al. conducted a prospective, multicenter study in 359 cases to evaluate the new and emerging causes of caP. it was found that the common causative agents of caP are S. pneumoniae (15.3%), H. infuenzae (10.9%), Legionella spp. (6.7%) and C. pneumoniae (6.1%). Mortality was the highest for S. aureus (50%) and the lowest for C. pneumoniae (4.5%). Mortality was not seen with M. pneumoniae. Pneumonia due to aerobic Gram-negative organisms was uncommon, even though empirical therapy with combination of broad-spectrum antibiotics was often used in this subgroup. The study concluded that empiric antibiotic prescriptions must be infuenced by the realization that C. pneumoniae and Legionella spp. are common etiologies for caP. 3 The emerging etiologies for caP were also examined in a 12-month prospective study, which evaluated the microbiological yield with a new diagnostic polymerase chain reaction (Pcr) platform along with conventional methods. 4 The microbiological tests used were as follows: 4 • Culture of samples of blood, sputum, and nasopharyngeal secretion. • Analysis of sputum samples by real-time quantitative PCR for S. pneumoniae, H. infuenzae, and Moraxella catarrhalis. • Analysis of nasopharyngeal secretions by PCR. • Serological testing for M. pneumoniae, C. pneumoniae, and viruses common in the respiratory tract. • Detection of pneumococcal and L pneumophila antigens by urine antigen assays. it was possible to establish microbial etiology in about 67% (n=124) of patients. a microbiological agent was identifed in 89% of the patients with complete sampling. S. pneumoniae [70 patients (38%)] and respiratory virus [53 patients (29%)] were the most frequently detected pathogens. forty-three (35%) patients out of 124, were detected with two or more pathogens. The bacteriological …