Clinical Cure and Microbiological Eradication in Respiratory Tract Infections

Abstract

Aims: To study the concordance between clinical cure and microbial eradication in severe respiratory tract

infections.

Methods & Material: A prospective cohort study was done at a tertiary care teaching hospital. Patients

above 18 years of age with respiratory tract infections confirmed with positive sputum cultures participated

in the study. Microbiological eradication was considered complete when no microorganism was isolated on

2 consecutive sputum cultures.

Results: The number of valid cases was 102. The mean age of patients was 58.6±16.1 (range, 19-82 years).

Complete eradication of microorganisms was achieved in 54.5%(n=55) cases. In 33% (n=34) clinically

successful cases, strains like Pseudomonas, Acinetobacter and Kleibsiella were not eradicated and were

isolated at study end point on repeat sputum culture. Relapse was observed in 9.2% (n=9) cases. On multiple

logistic regression to ascertain the impact of independent variables on dependent variable (clinical cure/

microbiological cure), it was observed that increasing age, odds ratio=1.66(95% CI, 1.34-2.03), patient?s

background OR=6.4 (95% CI, 0.68-63.4), ventilatory support OR=2.8 (95% CI, 0.4-22.4) significantly

(P<0.05) influenced end stage clinical outcome. Increasing age, odds ratio=2.33 (95% CI, 1.56- 2.84)

and ventilatory support OR=3.4 (95% CI, 2.46-4.66) significantly (P<0.05) influenced microbiological

eradication.

Conclusion: Clinical endpoint and microbiological eradication correlated in 54.5% cases. Discordance

or failed eradication was more frequent in infections with Acinetobacter, Enterobacter and Pseudomonas.

Failure to eradicate microorganisms was commonly associated with emergence of resistance to antibiotics.