An Observational Study of The Utilization Pattern of Antibiotics in A Tertiary Care Hospital

Antibiotics are medicines that kill bacteria or inhibit their growth and are central to the treatment of bacterial infections. Tertiary care hospitals manage complex and severe conditions using advanced diagnostic and therapeutic facilities; consequently, these hospitals are major centers of antibiotic use. The same clinical complexity can also promote excessive or inappropriate prescribing, prolonged hospitalization, adverse treatment outcomes, and the emergence of multidrug-resistant organisms [1-7].

Antibiotics may be classified as bactericidal or bacteriostatic according to their in-vitro effect. Bactericidal agents directly kill susceptible bacteria, whereas bacteriostatic agents suppress bacterial multiplication. They may also be categorized as broad-spectrum or narrow-spectrum agents according to the range of organisms against which they are active. The minimum inhibitory concentration represents the lowest antibiotic concentration that prevents visible growth, whereas the minimum bactericidal concentration represents the concentration associated with a 1000-fold reduction in bacterial density at 24 hours.

Common bacteriostatic groups include glycylcyclines, tetracyclines, lincosamides, macrolides, oxazolidinones, and sulfonamides. Bactericidal groups include aminoglycosides, beta-lactams, fluoroquinolones, glycopeptides, cyclic lipopeptides, and nitroimidazoles. Rational selection requires consideration of the probable pathogen, site and severity of infection, local resistance patterns, patient characteristics, microbiological evidence, safety, and the need for broad- or narrow-spectrum coverage.

The need for this study arose from the rising burden of antimicrobial resistance, the importance of optimizing hospital antibiotic use, the need to improve patient outcomes and reduce complications, the requirement to support public-health efforts, and the need to strengthen and update clinical guidance for antibiotic prescribing. The investigation was therefore designed to describe actual inpatient prescribing practice and identify areas requiring antibiotic-stewardship intervention.

1.1 Aim

To evaluate the utilization pattern of antibiotics in a tertiary care hospital in order to assess prescribing trends, identify areas of irrational use, and promote rational antibiotic therapy.

1.2 Objectives

To analyze the frequency and pattern of antibiotic prescriptions across patient demographics.

To assess the appropriateness of antibiotic use based on the hospital antibiotic policy.

To identify the most commonly prescribed antibiotic classes and individual agents.

To examine the prevalence of empirical versus culture-based antibiotic prescribing.

2. MATERIALS AND METHODS

2.1 Study design and setting

This was a prospective observational study conducted at Sahyadri Super Speciality Hospital, Pune, a tertiary care hospital. The study covered six months, from October 2024 to March 2025, and included 300 hospitalized patients.

2.2 Eligibility criteria

Hospitalized patients of all age groups and genders who received at least one antibiotic during their inpatient stay and had complete medical records, including prescription details, diagnosis, and laboratory findings where applicable, were included. Outpatient-department patients, surgery patients, and critical-care-department patients were excluded.

2.3 Data collection and study procedure

After institutional ethics approval, eligible patients receiving systemic antibiotics were identified. Data were collected through a structured data collection form from medical records, medication charts, and laboratory reports. The recorded variables included age, gender, clinical diagnosis, medical history, clinical presentation, vital signs, laboratory investigations, antibiotic name, dose, frequency, route, duration, pharmacological class, culture and sensitivity results, empirical or definitive indication, length of hospital stay, and discharge antibiotics.

Antibiotics were classified using the Anatomical Therapeutic Chemical system and the WHO Access, Watch, and Reserve framework. Prescription appropriateness was assessed against the hospital antibiotic policy and available clinical guidance. Patient outcomes, adverse effects or complications, and microbiological evidence of resistance were considered where available.

2.4 Statistical analysis

The collected data were compiled and analyzed using descriptive statistics. Frequencies and percentages were calculated for demographic characteristics, route of administration, individual antibiotics and classes, number of antibiotics per patient, AWaRe groups, culture testing, culture samples, bacterial isolates, empirical or definitive therapy, and discharge prescriptions.

3. RESULTS

A total of 300 hospitalized patients and 520 antibiotic prescriptions were evaluated during the study period. The principal findings are presented below.

3.1 Gender-wise distribution

Among the 300 patients, 159 (53%) were male and 141 (47%) were female, showing a slightly higher proportion of male patients receiving antibiotic therapy.

 

 

Figure 1. Gender-wise distribution of study participants.

 

 

Figure 2. Age-wise distribution of study participants.

 

 

Figure 3. Route of antibiotic administration.

 

 

Figure 4. Most frequently prescribed individual antibiotics.

 

 

Figure 5. Pharmacological classes of antibiotics used during treatment.

 

 

Figure 6. Number of antibiotics administered per patient.

 

 

Figure 7. Distribution of antibiotics according to the WHO AWaRe classification.

 

 

Figure 8. Proportion of patients who underwent culture and sensitivity testing.

 

 

Figure 9. Types of microbiological samples collected.

 

 

Figure 10. Bacterial isolates identified from positive microbiological tests.

 

 

Figure 11. Classification of antibiotic therapy as empiric or definitive.

 

 

Figure 12. Antibiotics prescribed at the time of hospital discharge.

DISCUSSION

The study describes a prescribing environment dominated by empiric, intravenous, broad-spectrum antibiotic use. Ceftriaxone and cephalosporins were the leading individual agent and class, respectively. Similar patterns were described in the thesis literature review. Deewan and colleagues reported that beta-lactams accounted for 79% of antimicrobial use and ceftriaxone was used in 30% of cases in a tertiary care hospital, closely resembling the present ceftriaxone proportion of 31.10% [6]. Studies from Bangladesh and Tanzania also documented frequent empiric prescribing, extensive use of Watch antibiotics, and insufficient microbiological testing [2,3].

Intravenous therapy represented 78% of the prescriptions in the present study. The predominance of injectable antibiotics is consistent with hospital and critical-care prescribing patterns described in the reviewed studies, where rapid therapeutic action and the severity of illness favored parenteral treatment [3,5]. The discharge data nevertheless demonstrate step-down to oral therapy, particularly cefuroxime axetil, cefixime, cefpodoxime proxetil, azithromycin, doxycycline, and amoxicillin-clavulanate.

The high use of multiple antibiotics is another important finding. Two-antibiotic therapy was slightly more common than single-antibiotic therapy, and 13% of patients received three or more agents. This may reflect treatment of severe, polymicrobial, or uncertain infections, but it also increases the importance of reassessment, de-escalation, duration review, adverse-effect monitoring, and documentation. The surgical-department study summarized in the thesis similarly reported an average of 2.4 antibiotics per prescription and frequent empiric use [7].

Culture testing was performed in 46% of patients, while positive organisms were identified in 19 samples. The present rate of culture testing was higher than the 34.71% described by Deewan and colleagues but still left more than half of the patients without microbiological confirmation [6]. The Tanzania study likewise identified inadequate culture use and frequent empiric therapy as areas requiring improvement [3]. Increased sampling before antibiotic initiation, timely microbiology reporting, and active review of results could improve targeted prescribing.

The WHO AWaRe analysis is particularly relevant to stewardship. Watch antibiotics accounted for 75% of prescriptions, while Access agents represented only 20%. This is consistent with the Bangladesh review, which described extensive empirical Watch-group use, and the surgical study, in which Watch antibiotics such as cefoperazone-sulbactam predominated [2,7]. Although Reserve agents accounted for only 5%, the high reliance on Watch antibiotics indicates a need to promote Access agents for common infections whenever clinically appropriate.

The distribution of bacterial isolates included gram-negative, gram-positive, atypical, and mycobacterial organisms. Escherichia coli was the most common isolate, followed by Staphylococcus aureus. Although the number of positive cultures was limited, the diversity of organisms supports the need for local surveillance and periodic antibiogram development. Better diagnostic integration could reduce unnecessary broad-spectrum exposure and enable earlier transition from empiric to definitive therapy.

CONCLUSION

This prospective observational study provides a detailed overview of antibiotic utilization in a tertiary care hospital. Antibiotic prescribing was characterized by high use of cephalosporins and ceftriaxone, predominant intravenous administration, frequent combination therapy, extensive empirical treatment, and major dependence on the WHO Watch group. Culture-guided therapy was underutilized, and positive cultures were obtained in a limited proportion of tested patients.

The findings support the need for robust antibiotic-stewardship programs that promote appropriate sampling before therapy, timely review of culture results, de-escalation from empiric to definitive treatment, preference for Access antibiotics when suitable, review of intravenous duration, rational combination therapy, and careful discharge prescribing. Continued surveillance, healthcare-provider education, and integration of hospital antibiotic guidelines into routine clinical practice are essential to improve patient outcomes and reduce antimicrobial resistance.

ACKNOWLEDGMENT

The authors acknowledge Dr. Trupti Tuse, Principal, Abhinav Education Society’s College of Pharmacy, Pune; Dr. Kumudini Pawar, research guide; Dr. Rahul Surve, clinical co-guide; Sahyadri Super Speciality Hospital, Hadapsar, Pune; and the patients who participated in the study.

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