European Journal of Cardiovascular Medicine

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder characterized by persistent airflow limitation and chronic airway inflammation. It is a major cause of morbidity and mortality globally, ranking as the third leading cause of death worldwide ^[1]. Acute exacerbations of COPD (AECOPD) are defined as a sudden worsening of respiratory symptoms, including increased dyspnea, cough, and sputum production, beyond normal day-to-day variations. These episodes contribute significantly to hospitalizations, accelerated decline in lung function, and increased mortality ^[2,3].

Bacterial infections are implicated in a substantial proportion of AECOPD cases, with common pathogens including Haemophilus influenzae, Streptococcus pneumoniae, Moraxella catarrhalis, and Pseudomonas aeruginosa ^[4,5]. Viral infections and environmental pollutants may also precipitate exacerbations. The emergence of antimicrobial resistance among respiratory pathogens poses a major challenge in effective management, highlighting the need for local surveillance of microbial patterns and susceptibility profiles ^[6,7].

Early recognition and appropriate treatment of AECOPD, including targeted antibiotic therapy based on culture and sensitivity, bronchodilator therapy, and supportive care, have been shown to improve clinical outcomes, reduce treatment failure, and prevent recurrent exacerbations ^[8]. Despite this, limited data are available regarding the clinical characteristics, microbial aetiology, and treatment outcomes of AECOPD patients, particularly in rural and resource-limited settings. Such data are essential for guiding evidence-based management and optimizing patient care.

Aim: -

To evaluate the clinical profile, microbial aetiology, antimicrobial sensitivity pattern, and treatment outcomes of patients presenting with acute exacerbation of chronic obstructive pulmonary disease.

Objectives: -

To assess the demographic characteristics and clinical presentation of patients with AECOPD.

To identify the bacterial pathogens responsible for AECOPD.

To determine the antimicrobial sensitivity pattern of isolated pathogens.

To evaluate treatment modalities administered and their clinical outcomes in AECOPD patients.

To analyze the correlation between microbial aetiology, antibiotic sensitivity, and treatment outcomes.

Study Design and Setting: -

This prospective observational study was conducted in the Department of Medicine, pharmacology and Pulmonology at Konaseema institute of medical sciences Amalapuram AP, a tertiary care centre, over a period of July 2024 to July 2025. a tertiary care centre catering rural populations. The study protocol was approved by the Institutional Ethics Committee, and written informed consent was obtained from all participants.

Study Population

Patients aged ≥40 years, diagnosed with COPD according to GOLD 2025 criteria, and presenting with an acute exacerbation were included. Acute exacerbation was defined as a sudden increase in dyspnea, sputum volume, or sputum purulence requiring a change in regular medication ^[1].

Exclusion criteria:

Asthma or other chronic respiratory disorders

Recent hospitalization (within 4 weeks) for pneumonia or other respiratory infections

Immunocompromised patients, including those on chemotherapy or long-term corticosteroids

Patients unwilling to provide informed consent

Sample Size

A total of [insert number, e.g., 60] consecutive patients meeting inclusion criteria were enrolled during the study period.

Data Collection

Demographic details, smoking history, comorbidities, prior exacerbations, and baseline spirometry (FEV1, FVC, FEV1/FVC ratio) were recorded. Clinical features, including dyspnea grade, cough, sputum characteristics, and systemic symptoms, were documented at presentation.

Microbiological Investigation

Sputum samples were collected aseptically before initiation of antibiotic therapy. Samples underwent:

Gram staining for preliminary assessment

Culture and sensitivity testing using standard microbiological protocols

Pathogen identification based on colony morphology, biochemical tests, and automated identification systems where available

Antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method according to CLSI 2023 guidelines ^[9].

Treatment and Outcome Assessment

Patients were managed according to standard hospital protocols, including:

Empirical or culture-guided antibiotics

Bronchodilators (short-acting and long-acting)

Corticosteroids (oral or inhaled)

Oxygen supplementation as required

Treatment outcomes were classified as:

Clinical improvement: resolution of symptoms at discharge

Treatment failure: -

persistence or worsening of symptoms requiring therapy modification or ICU admission

Mortality: in-hospital death

Statistical Analysis

Data were analyzed using SPSS version 25.0 (IBM Corp., Armonk, NY, USA). Continuous variables were expressed as mean ± standard deviation (SD) or median (IQR), while categorical variables were presented as frequencies and percentages. Associations between microbial patterns, antibiotic sensitivity, and clinical outcomes were assessed using Chi-square or Fisher’s exact test, with p < 0.05 considered statistically significant.

Demographic and Clinical Characteristics: -

A total of 60 patients with acute exacerbation of COPD were included. The mean age was 62.5 ± 8.7 years, with 48 (80%) males and 12 (20%) females. Most patients were smokers (45, 75%). Common comorbidities included hypertension (30, 50%) and diabetes mellitus (24, 40%). The predominant clinical features at presentation were increased dyspnea (54, 90%), cough (51, 85%), and purulent sputum (48, 80%).

Table 1. Demographic and Clinical Characteristics of Patients with AECOPD (n = 60)

Microbiological Profile: - Sputum cultures were positive in 24 (40%) patients. The most frequently isolated pathogens were Klebsiella pneumoniae (9, 37.5%), Pseudomonas aeruginosa (7, 29.2%), Acinetobacter baumannii (3, 12.5%), Escherichia coli (3, 12.5%), and Staphylococcus aureus (2, 8.3%).

Table 2. Bacterial Isolates from Sputum Cultures (n = 24)

Antimicrobial Sensitivity Pattern: - Antimicrobial susceptibility testing showed variable resistance among the isolates. K. pneumoniae was highly sensitive to piperacillin-tazobactam (90%) and meropenem (85%), while resistant to ampicillin (70%). P. aeruginosa remained sensitive to piperacillin-tazobactam (80%) and meropenem (75%) but resistant to ceftazidime (60%). S. aureus isolates were sensitive to vancomycin (100%) and linezolid (100%), with 30% resistance to methicillin.

Table 3. Antimicrobial Sensitivity of Bacterial Isolates

Treatment and Clinical Outcomes: -

All patients received standard management for AECOPD, including bronchodilators, corticosteroids, and empirical antibiotics, later adjusted according to culture and sensitivity results. Clinical outcomes were as follows: clinical improvement at discharge in 45 (75%) patients, treatment failure requiring ICU care in 9 (15%), and in-hospital mortality in 6 (10%)

Table 4. Treatment Outcomes in AECOPD Patients (n = 60)

Correlation Between MDR Organisms and Outcomes: - Patients infected with multidrug-resistant (MDR) organisms (n = 8) had a significantly higher rate of treatment failure (37.5%) compared to non-MDR infections (10%) (p < 0.05), indicating the impact of resistant pathogens on clinical outcomes

Acute exacerbations of COPD (AECOPD) significantly contribute to morbidity, hospitalizations, and healthcare burden. In this study, the mean age of patients was 62.5 years, with a predominance of males (80%), consistent with previous reports that COPD predominantly affects older males due to higher smoking prevalence ^[10,11]. The majority of patients had comorbidities such as hypertension (50%) and diabetes mellitus (40%), which have been associated with worse outcomes during exacerbations ^[12].

Clinical presentation was dominated by increased dyspnoea (90%), cough (85%), and purulent sputum (80%), aligning with findings from prior observational studies ^[13]. These symptoms reinforce the importance of early recognition of exacerbations to prevent progression and hospitalization.

Sputum culture positivity was 40%, which is comparable to other studies reporting 35–50% positivity in AECOPD patients ^[14,15]. Klebsiella pneumoniae (37.5%) and Pseudomonas aeruginosa (29.2%) were the most common isolates, suggesting a predominance of Gram-negative bacteria in this cohort. Similar findings were reported in studies from tertiary care centres in India, where Gram-negative organisms were the primary pathogens in hospitalized AECOPD patients ^[16,17].

Antimicrobial susceptibility testing revealed high sensitivity of K. pneumoniae to piperacillin-tazobactam (90%) and meropenem (85%), while resistance to ampicillin was noted in 70% of isolates. P. aeruginosa showed resistance to ceftazidime (60%) but sensitivity to piperacillin-tazobactam (80%). These results highlight the importance of performing culture-guided therapy, as empirical antibiotics alone may be inadequate due to rising antimicrobial resistance ^[18,19].

Clinical outcomes were favourable in 75% of patients, while 15% required ICU care and 10% succumbed during hospitalization. Patients infected with multidrug-resistant organisms experienced higher rates of treatment failure (37.5%) compared to those with non-resistant infections (10%), underscoring the adverse impact of antimicrobial resistance on prognosis. Similar observations have been reported in other studies, emphasizing the need for antibiotic stewardship in COPD management ^[20,21].

This study reinforces several key points: early identification of AECOPD, timely microbiological evaluation, and targeted antimicrobial therapy improve patient outcomes. Furthermore, monitoring local antimicrobial susceptibility patterns is essential for selecting effective empiric therapy and reducing the risk of treatment failure. Limitations of the study include its single-centre design and relatively small sample size, which may limit generalizability.

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