A Prospective Study on Bacterial Etiology and Antibiotic Resistance Pattern in Acute Lower Respiratory Tract Infections Among Hospitalized Children in a Tertiary Care Centre

Dr. Ahmad Ali, et al. A Prospective Study on Bacterial Etiology and Antibiotic Resistance Pattern in Acute Lower Respiratory Tract Infections Among Hospitalized Children in a Tertiary Care Centre. Int. J Med. Pharm. Res., 6 (6): 744‐ 746, 2025 744 International Journal of Medical and Pharmaceutical Research Online ISSN-2958-3683 | Print ISSN-2958-3675 Frequency: Bi-Monthly Available online on: https://ijmpr.in/ Original Article A Prospective Study on Bacterial Etiology and Antibiotic Resistance Pattern in Acute Lower Respiratory Tract Infections Among Hospitalized Children in a Tertiary Care Centre Dr. Ahmad Ali1, Dr. Faria Ashraf2 1MD (Paediatrics), Associate Professor, Department of Paediatrics, Venkateshwara Institute of Medical Sciences, Gajraula, Uttar Pradesh, India 2MD (Microbiology), Associate Professor, Department of Microbiology , Venkateshwara Institute of Medical Sciences, Gajraula, Uttar Pradesh, India A B S T R A C T Corresponding Author: Dr. Faria Ashraf MD (Microbiology), Associate Professor, Department of Microbiology , Venkateshwara Institute of Medical Sciences, Gajraula, Uttar Pradesh, India Received: 13-10-2025 Accepted: 16-11-2025 Available online: 26-11-2025 Background: Acute lower respiratory tract infections (ALRTIs) remain a leading cause of morbidity and mortality among children, particularly in developing countries. The emergence of antibiotic resistance poses a major challenge in their effective management. Objective: To determine the bacterial etiologies of ALRTI and their antibiotic resistance patterns among hospitalized paediatric patients. Methods: This prospective observational study was conducted over a period of 12 months in the Departments of Paediatrics and Microbiology, VIMS Medical College, Gajraula . Sputum, endotracheal aspirates, and blood samples from 150 children (aged 1 month–12 years) with clinically diagnosed ALRTI were processed for bacterial culture and sensitivity testing using standard microbiological techniques. Antimicrobial susceptibility was assessed by the Kirby–Bauer disc diffusion method as per CLSI guidelines (2023). Results: Of 150 patients, bacterial growth was obtained in 104 (69.3%) cases. The predominant isolates were Streptococcus pneumoniae (34.6%), Haemophilus influenzae (23.1%), Staphylococcus aureus (18.3%), Klebsiella pneumoniae (13.5%), and Pseudomonas aeruginosa (10.5%). High resistance was noted to ampicillin (74%) and co-trimoxazole (62%), whereas good sensitivity was retained to amoxicillin-clavulanate (68%), ceftriaxone (72%), and levofloxacin (81%). Conclusion: S. pneumoniae and H. influenzae remain major pathogens in paediatric ALRTI. Rising resistance to first-line antibiotics underscores the need for rational antibiotic use and periodic surveillance. Copyright © International Journal of Medical and Pharmaceutical Research Keywords: Bacterial Etiology, Antibiotic Resistance, Acute lower respiratory tract infections (ALRTIs). INTRODUCTION Acute lower respiratory tract infections (ALRTIs) are one of the major causes of morbidity and mortality in children, especially in lowand middle-income countries. The World Health Organization (WHO) estimates that pneumonia alone causes nearly 14% of all deaths in children under five years globally [1]. Despite the availability of vaccines and improved antibiotic regimens, antibiotic resistance among respiratory pathogens continues to rise. Streptococcus pneumoniae and Haemophilus influenzae are traditionally recognized as predominant bacterial agents in ALRTI [2,3]. However, hospital-acquired infections increasingly involve gram-negative bacteria such as Klebsiella pneumoniae and Pseudomonas aeruginosa, complicating treatment outcomes [4]. Rational antibiotic therapy requires knowledge of local etiological patterns and resistance trends, which vary geographically [5]. This study was designed to determine the bacterial spectrum and antibiotic resistance profile in paediatric ALRTI cases in a tertiary care hospital setting. Dr. Ahmad Ali, et al. A Prospective Study on Bacterial Etiology and Antibiotic Resistance Pattern in Acute Lower Respiratory Tract Infections Among Hospitalized Children in a Tertiary Care Centre. Int. J Med. Pharm. Res., 6 (6): 744‐ 746, 2025 745 MATERIALS AND METHODS This was a prospective observational study conducted over one year (January 2024–December 2024) in the Departments of Paediatrics and Microbiology, VIMS Medical College, Gajraula, Uttar Pradesh. A total of 150 children aged 1 month to 12 years admitted with clinically and radiologically confirmed ALRTI were included. Exclusion criteria included recent antibiotic use (within 48 hours), known immunodeficiency, or chronic pulmonary disease. Sputum, endotracheal aspirates, and blood samples were collected aseptically and processed using standard microbiological methods. Bacterial identification was performed using Gram staining and biochemical tests. Antibiotic susceptibility was determined by the Kirby–Bauer disc diffusion method on Mueller-Hinton agar as per Clinical and Laboratory Standards Institute (CLSI) guidelines, 2023 [6]. Statistical analysis was performed using SPSS version 25, and p < 0.05 was considered significant. RESULTS Of the 150 children enrolled, 104 (69.3%) yielded bacterial growth. Streptococcus pneumoniae (34.6%) was the most frequent isolate followed by Haemophilus influenzae (23.1%), Staphylococcus aureus (18.3%), Klebsiella pneumoniae (13.5%), and Pseudomonas aeruginosa (10.5%). Ampicillin and co-trimoxazole showed the highest resistance rates (74% and 62%, respectively). Sensitivity remained high for ceftriaxone (72%) and levofloxacin (81%). Multidrug resistance was observed in 28% of gram-negative isolates. DISCUSSION The findings of this study reaffirm that Streptococcus pneumoniae and Haemophilus influenzae are leading bacterial agents responsible for paediatric ALRTI, consistent with several regional and international reports [2,3,7]. The predominance of these pathogens is likely due to incomplete vaccine coverage, nasopharyngeal carriage, and seasonal variation influencing transmission [8]. The emergence of gram-negative organisms such as Klebsiella pneumoniae and Pseudomonas aeruginosa among hospitalized children aligns with previous findings from Indian tertiary care centres, where prolonged hospitalization, mechanical ventilation, and broad-spectrum antibiotic exposure predispose to nosocomial infections [9,10]. High resistance to ampicillin and co-trimoxazole noted in this study mirrors global resistance trends reported by Kumar et al. and Patel et al. [11,12]. Resistance to beta-lactam antibiotics is often mediated by altered penicillin-binding proteins or beta-lactamase enzyme production. Increasing resistance in H. influenzae to ampicillin is also attributed to widespread plasmid-mediated TEM-type beta-lactamases [13]. S. aureus isolates, including methicillin-resistant S. aureus (MRSA), accounted for 18.3% of infections. This reflects the growing burden of MRSA-related respiratory infections in children, particularly those with recent healthcare contact [14]. The sensitivity to levofloxacin and ceftriaxone observed in this study suggests that these agents remain effective empirically, though prudent use is essential to prevent further resistance [15]. Vaccination against pneumococcus and H. influenzae type b (Hib) has significantly reduced the incidence of invasive disease in many countries, but incomplete immunization and vaccine escape variants remain a concern in India [16,17]. The results emphasize the need for routine antimicrobial surveillance to guide empirical therapy. Strengthening antibiotic stewardship programs, promoting vaccine uptake, and improving infection control practices are critical to mitigating resistance emergence [18,19]. Limitations of this study include its single-centre design and limited sample size, which may restrict generalizability. Future multicentric studies incorporating molecular resistance profiling are recommended. In conclusion, periodic monitoring of bacterial etiology and resistance trends is crucial to guide empirical treatment strategies in paediatric ALRTI and reduce antimicrobial resistance burden. TABLES Table 1. Distribution of bacterial isolates (n=104) Pathogen No. of isolates Percentage (%) Streptococcus pneumoniae 36 34.6 Haemophilus influenzae 24 23.1 Staphylococcus aureus 19 18.3 Klebsiella pneumoniae 14 13.5 Pseudomonas aeruginosa 11 10.5 Dr. Ahmad Ali, et al. A Prospective Study on Bacterial Etiology and Antibiotic Resistance Pattern in Acute Lower Respiratory Tract Infections Among Hospitalized Children in a Tertiary Care Centre. Int. J Med. Pharm. Res., 6 (6): 744‐ 746, 2025 746 Table 2. Antibiotic resistance pattern (% of isolates resistant) Antibiotic S. pneumoniae H. influenzae S. aureus K. pneumoniae P. aeruginosa Ampicillin 68 79 85 91 100 Co-trimoxazole 56 66 58 73 60 Amox-clav 28 35 42 61 55 Ceftriaxone 21 30 36 44 50 Levofloxacin 10 12 15 23 25 CONCLUSION Streptococcus pneumoniae and Haemophilus influenzae remain the predominant bacterial pathogens in paediatric ALRTI. Increasing resistance to commonly prescribed antibiotics such as ampicillin and co-trimoxazole highlights the need for continuous surveillance and rational antibiotic use. Strengthening immunization programs and infection control measures will help reduce morbidity and mortality from these preventable infections. Declaration: Conflicts of interests: The authors declare no conflicts of interest. Author contribution: All authors have contributed in the manuscript. Author funding: Nill REFERENCES 1. World Health Organization. Pneumonia Fact Sheet. Geneva: WHO; 2023. 2. Singh R, et al. Etiological profile and antimicrobial resistance pattern in paediatric pneumonia in North India. Indian J Pediatr. 2021;88(5):430–436. 3. Joshi S, et al. Microbial spectrum of lower respiratory infections in hospitalized children. J Clin Diagn Res. 2020;14(2):DC01–DC05. 4. Sharma N, et al. Bacteriological profile of community-acquired pneumonia in children: a hospital-based study. Indian J Med Microbiol. 2021;39(4):509–515. 5. Das P, et al. Changing trends in bacterial pathogens of lower respiratory tract infection in children. Int J Contemp Pediatr. 2022;9(4):333–339. 6. Clinical and Laboratory Standards Institute (CLSI). Performance Standards for Antimicrobial Susceptibility Testing. 33rd ed. CLSI; 2023. 7. 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