Bacteriology
Infectious etiologies in acute exacerbation of COPD

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Abstract

Acute exacerbation (AE) is a frequent episode during the prolonged chronic course of chronic obstructive pulmonary disease (COPD), which entails significant morbidity and mortality. The purpose of this study was to determine the frequency distribution of infectious etiologies in these episodes. Two hundred forty hospitalizations for AECOPD were included in a prospective, purely serologically based study. Paired sera were obtained for each of the hospitalizations and were tested using immunofluorescence or EIA methods to identify 13 different pathogens. Only significant changes in antibody titers were considered diagnostic. The mean age ( ± SD) of the patients was 66.8 ± 9.0 years and 179 (84%) were males. In 175 (72.9%) hospitalizations at least one infectious etiology was identified. In 117 (48.8%) hospitalizations at least one of 7 viral etiologies was identified. In 72 (30.0%) hospitalizations at least one of the following atypical bacteria was identified: Legionella spp. in 40 (16.7%), Mycoplasma pneumoniae in 34 (14.2%), and Coxiella burnetii in a single hospitalization. In 58 (24.2%) hospitalizations at least one classic bacterial etiology was found: Streptococcus pneumoniae in 48 (20.0%), Hemophilus influenzae in 10 (4.2%) and Moraxella catarrhalis in 9 (3.8%). More than one etiology was found in 72 (30.0%) hospitalizations. There were no significant differences in the etiologic distribution when the patients were classified by severity of airway obstruction or the clinical type of the exacerbation. We conclude that in most cases of hospitalization due to AECOPD the infectious etiology is viral or atypical bacteria and is classic bacteria in only a minority of cases. More than one etiologic cause can be identified in a third of the cases. The frequency distribution of the etiologies is not associated with the severity of airway obstruction or the clinical type of the exacerbation. The results of our study suggest that atypical bacteria should be covered in antibiotic regimens recommended for AECOPD. This issue should be addressed in future studies.

Introduction

In the setting of the prolonged, chronic course of chronic obstructive pulmonary disease (COPD), patients often have acute exacerbations (AECOPD). The principal and dominant etiology in the overwhelming majority of episodes is infectious (McHardy et al., 1980). Despite the high frequency of AECOPD in both ambulatory and hospital settings, few studies have determined in a comprehensive manner the frequency distribution of the various infectious etiologies in these episodes. This paucity of studies is particularly striking in light of the very large body of work that has been done on another infectious pulmonary disease, community-acquired pneumonia (CAP). Even among the few studies that attempted to assess the issue of infectious etiologies of AECOPD, most were based primarily on cultures of respiratory tract secretions, an approach that entails serious methodological problems (Murphy & Sethi, 1992). Attempts to study the issue of etiology indirectly by evaluating responses to various antibiotic therapies for AECOPD Anthonisen et al 1987, Elmes et al 1957 are no less problematic since the response rate to placebo therapy is 55% (Anthonisen et al., 1987).

Technological developments that have taken place over the last decade have significantly improved serologic diagnostic tools for infectious diseases in general and for respiratory infections in particular. This development has enabled investigators to diagnose respiratory infections caused by classic bacteria, atypical bacteria and viruses with satisfactorily reliable serologic methods. The aim of this prospective study was to use these serologic tools to identify the spectrum of infectious etiologies for AECOPD among patients hospitalized for these episodes, and to determine their distribution in terms of the baseline severity of the COPD and the clinical manifestations of the exacerbation.

Section snippets

Patients

All patients hospitalized for AECOPD during the period between November 1, 1997 and March 15, 1999 in the internal medicine and intensive care wards of the Soroka Medical Center in Beer-Sheva Israel who met the inclusion criteria, and gave consent to participate, were included in the study. All first hospitalizations in the study period were included as well as repeat hospitalizations for AECOPD of patients in the study population, if the hospitalization took place at least six months after the

Results

The study consisted of 250 hospitalizations for AECOPD among 219 different COPD patients during the 16.5-month period. In 241 cases (96.4%) a convalescence serum sample was obtained at a mean of 24.7 ± 5.6 days (range 17–53 days) after the first sample was taken at the beginning of the hospitalization. Since the etiologic diagnoses in this study were based on changes in antibody titer between the acute phase serum and the convalescence serum, we did not include in the frequency distribution

Discussion

A comprehensive review on the subject of infectious etiologies for AECOPD was published in 1992 by Sethi and Murphy (1992). Although nine years have passed since then, their conclusions are still valid and have been confirmed by the results of studies published recently. The vast majority of studies on etiologies of AECOPD were based almost solely on bacteria isolated from cultures of patients’ sputum. These studies have consistently found that the bacteria isolated from patients’ sputum are H.

References (23)

  • Y. Holloway et al.

    Demonstration of circulating pneumococcal immunoglobulin G immune complexes in patients with community-acquired pneumonia by means of an enzyme-linked immunosorbent assay

    J Clin Microbiol

    (1993)
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