Etiology and Anti-microbial Sensitivity of Organisms Causing Community Acquired Pneumonia: A Single Hospital Study

The objective of this study was to identify the common etiological pathogens causing community acquired pneumonia (CAP) in our hospital and sensitivity patterns to the common antibiotics used.

This study was undertaken in a 750 bedded multi-specialty referral hospital in Kerala catering to both urban and semi-urban populations. It is a prospective study of patients who attended the medical out-patient department and those admitted with a clinical diagnosis of CAP, during the year 2009. Data were collected based on detailed patient interview, clinical examination and laboratory investigations. The latter included sputum culture and sensitivity pattern. These were tabulated and percentage incidence of etiological pathogens calculated. The antimicrobial sensitivity pattern was also classified by percentage and expressed as bar diagram.

The study showed Streptococcus pneumoniae to be the most common etiological agent for CAP, in our hospital setting. The other organisms isolated in order of frequency were Klebsiella pneumoniae, Pseudomonas aeruginosa, Alpha hemolytic streptococci, Escherichia coli, Beta hemolytic streptococci and atypical coli. S. pneumoniae was most sensitive to linezolid, followed by amoxicillin-clavulanate (augmentin), cloxacillin and ceftriaxone. Overall, the common pathogens causing CAP showed highest sensitivity to amikacin, followed by ofloxacin, gentamycin, amoxicillin-clavulanate (augmentin), ceftriaxone and linezolid. The least sensitivity rates were shown to amoxicillin and cefoperazone.

In a hospital setting, empirical management for cases of CAP is not advisable. The present study has shown S. pneumoniae as the most likely pathogen and either linezolid or amikacin as the most likely effective antimicrobial in cases of CAP, in our setting.