COPD is a chronic, slowly advancing pulmonary condition associated with irreversible airflow restriction caused by long-term exposure to inhaled toxins such as cigarette smoke, industrial emissions, and biomass fuel fumes. Continuous inflammatory activity leads to progressive airway narrowing and parenchymal injury. AECOPD refers to abrupt symptomatic aggravation beyond routine day-to-day variations, clinically manifested by intensified breathlessness, increased cough frequency, and alteration in sputum quantity or color. These episodes are major determinants of lung function decline, increased hospitalization frequency, and impaired patient well-being. [1-4]

Microbial infection, especially bacterial invasion, plays a dominant role in triggering exacerbations, although viruses and environmental factors also contribute. Differentiating harmless colonization from active infection has been a long-standing clinical challenge. More reliable sampling approaches have shown that bacterial isolation rates rise significantly during acute exacerbations compared with stable disease phases, indicating a causative link rather than incidental presence. [2,4]

Several investigations from India, Nepal, Egypt, and other developing healthcare environments have documented a broad range of bacterial isolates in AECOPD, often highlighting gram-negative organisms as predominant, with regional differences in drug response. [1,3,5-7] Research from South-Asian populations further reinforces the importance of laboratory-driven antibiotic decisions due to shifting pathogen prevalence and increasing resistance pressure. [5,7-9]

Given the fluctuating nature of airway microbiota and the lack of comprehensive regional data from certain Indian centers, localized microbial profiling becomes essential. Unverified empirical antibiotic use increases the risk of ineffective treatment and fosters antimicrobial resistance. [3,5,6] Therefore, the present study focuses on identifying aerobic bacterial triggers and their susceptibility trends to assist clinicians in selecting more effective and rational antibiotics

MATERIALS AND METHODS

This real-time prospective observational study was implemented in the Department of Pulmonary Medicine at Siddhartha Medical College and Government General Hospital, Vijayawada between March 2024 and May 2025. One hundred and fifty patients aged above 18 years with previously confirmed COPD diagnosis and presenting with clinical features of acute exacerbation were enrolled after obtaining informed consent.

Morning expectorated sputum was collected using sterile wide-mouth, sealed containers. Sample adequacy was verified visually prior to processing. Microscopic evaluation was initiated using Gram stain, followed by inoculation onto standard aerobic culture media. Bacterial species were confirmed using accepted biochemical and morphological identification protocols.

Drug susceptibility was analyzed through the Kirby–Bauer disk diffusion method. Zone diameters were interpreted using CLSI recommendations. In addition to laboratory procedures, patient-specific clinical information including age, gender, symptoms, and prior treatment exposure were documented in structured case sheets. All results were categorized for final statistical interpretation.

Inclusion Criteria

• Individuals providing written or verbal consent
• Age above 18 years
• Established COPD diagnosis
• Presentation consistent with acute exacerbation symptoms

Exclusion Criteria

• Refusal to participate
• Age below 18 years
• Pregnant or breastfeeding individuals
• Terminal systemic illness
• Psychiatric disorders interfering with participation

RESULTS

• Majority of the study subjects belong to age group 2 ( 41-60 years) 50.6% and age group 3 ( 61-80 years) 40.7% highlighting that middle-aged and older patients are most affected.

TABLE 1- AGE WISE DISTRIBUTION

TABLE 2-GENDER WISE DISTRIBUTION

• In our study of 150 cases, 130 were male (86.7%) and 20 were female (13.3%).
• The predominance of male patients aligns with the well-documented higher prevalence of COPD among men, likely due to higher rates of smoking and occupational exposure to respiratory irritants.
• Culture reports showed that 60% of patients (90 out of 150) had a positive sputum culture, indicating the presence of bacterial infection, while 40% (60 out of 150) had a negative culture, suggesting no significant bacterial growth. The predominance of positive culture results (60%) suggests that bacterial infections play a significant role in Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD).
• Out of the organisms isolated Klebshiella pneumoniae is more common, followed by Pseudomonas aeruginosa and Escherichia coli.

TABLE 3- ORGANISM ISOLATED

• Klebsiella pneumoniae

High Sensitivity: Amikacin (23), Gentamicin (24), Piperacillin tazobactum (22)

High Resistance: Ceftriaxone (10), Cefepime (7), Ciprofloxacin (2)

• Pseudomonas aeruginosa

High sensitivity: Gentamicin (12), Cefepime (11), Levofloxacin (13)

Resistance Concern: Piperacillin-tazobactum (7), Ceftriaxone (5)

• coli

high sensitivity: Amikacin (9), Gentamicin (8), Meropenem (8)

High Resistance: Levofloxacin (8), Ceftriaxone (8), Cefotaxime (1)

TABLE 4- SENSITIVITY PATTERN

TABLE 5- RESISTANCE PATTERN

DISCUSSION

The study confirms that gram-negative bacteria form the major share of sputum isolates in AECOPD, particularly Klebsiella pneumoniae, Pseudomonas aeruginosa, and E. coli, a pattern consistent with previous observations across India, Nepal, and Egypt. [1,3,5-9]

The recurring identification of P. aeruginosa in patients with repeated hospital visits and prior antibiotic intake supports its known risk association in advanced COPD. [4,6] The maintained susceptibility of P. aeruginosa to levofloxacin, cefepime, gentamicin, and carbapenems reflects continued effectiveness of these drug classes regionally. [1,3,7]

Reduced responsiveness to ceftriaxone and piperacillin-tazobactam indicates growing resistance pressure, likely from frequent unverified empirical antibiotic administration, a challenge similarly noted in Indian and African reports. [3,6,7]

The favorable response of E. coli and K. pneumoniae to aminoglycosides and carbapenems also mirrors earlier hospital-based antibiogram trends. [3,5,6,9] The high resistance to third-generation cephalosporins further reflects antibiotic selection pressure due to their widespread unsupervised prescription. [5,7-9]

Evidence of chronic bacterial carriage in COPD airways during stable phases suggests that colonization may predispose individuals to future infective exacerbations, enhancing airway inflammation rather than representing a passive occurrence. [2,4,6]

Overall, these findings emphasize the need for laboratory-supported antibiotic selection and structured antimicrobial stewardship. [1-9]

CONCLUSION

This study reaffirms that bacterial infections constitute a major driver of AECOPD and emphasises the necessity of understanding local microbial patterns for effective treatment. Performing sputum culture and sensitivity testing before initiating therapy helps avoid unnecessary exposure to broad-spectrum antibiotics and reduces the emergence of resistant organisms. Using region-specific resistance patterns to guide management can significantly improve patient outcomes, reduce treatment-related expenses, and limit the spread of multidrug-resistant bacteria. Continuous surveillance of pathogen behaviour and resistance trends will remain essential to improving long-term care strategies for COPD patients.

LIMITATIONS

  The study was conducted in a single tertiary care centre, which may limit the generalizability of the findings to other regions or healthcare settings.

  Only aerobic bacterial pathogens were assessed; viral, fungal, and atypical organisms were not included, which may underestimate the true spectrum of etiological agents in AECOPD.

  Antibiotic usage prior to hospital presentation could not be fully controlled, potentially influencing culture positivity and resistance patterns.

  The study did not evaluate clinical outcomes in relation to specific pathogens or resistance profiles, which could provide additional insight into treatment effectiveness.

  Seasonal variations were not analysed separately, although they may influence infection patterns and exacerbation frequency.

DECLARATION

Conflicts of interest: the authors declare no conflicts of interest.

Author contribution- All authors have equally contributed in the manuscript.

Author funding- Nil.

REFERENCES

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