The term “Antibiotic Stewardship” (ABS) was first introduced in 1996 to address the growing challenge of Antimicrobial Resistance (AMR) in hospital settings, highlighting the need for evidence-based strategies to optimize the use of antimicrobials [1]. AMR has since evolved into a significant global health threat. In 2019 alone, antimicrobial resistance was associated with approximately 5 million deaths, and projections estimate that it could be responsible for up to 10 million deaths annually by 2050 [2,3]. In India, the burden of infections caused by antibiotic-resistant bacteria is alarmingly high and continues to rise [4]. The link between antibiotic consumption and the development of resistance is well-documented [2]. Several factors contribute to this growing resistance includes inappropriate and excessive use of antibiotics in humans, animals, and agriculture especially in low- and middle-income countries [2]. In humans, irrational prescribing practices, over-the-counter dispensing without prescriptions, and self-medication further exacerbate inappropriate antibiotic use [2]. Given that antibiotic use and misuse are the primary drivers of resistance, the implementation of antibiotic stewardship (AS) and formal antibiotic stewardship programmes (ASPs) is essential to promote the rational use of antibiotics [4]. These programmes function as comprehensive frameworks aimed at optimizing diagnostic and laboratory practices to ensure the early identification of infections and timely initiation of appropriate and targeted antimicrobial therapy [1]. Within hospitals, the intensive care unit (ICU) presents a unique challenge due to its high prevalence of antibiotic use much of which is unnecessary, inappropriate, or suboptimal [5]and has significantly contributed to the emergence of multidrug-resistant (MDR) organisms [2,6]. Patients admitted to the ICU are 5–10 times more likely to acquire infections compared to those in other hospital settings, primarily due to factors such as advanced age, immunosuppression, extended hospital stays, intensive antibiotic regimens, and invasive procedures [6]. Nosocomial infections with MDR pathogens in the ICU are linked to increased morbidity, mortality, healthcare costs, and prolonged hospitalizations [6,7]. Effective infection control measures are critical in preventing the colonization and spread of MDR organisms within Medical ICUs. Furthermore, days of therapy has been proposed as a useful metric to evaluate and monitor antimicrobial usage in these settings [2]. In light of these concerns, the present study aims to assess the rational use of antibiotics and antimicrobial utilization pattern in MICU Antimicrobial Stewardship in a tertiary care hospital.

The present study is a prospective, observational, questionnaire-based study conducted by the Department of Pharmacology in collaboration with the Department of General Medicine at KR Hospital, Mysore, involving patients admitted to the Medical Intensive Care Unit (MICU), and was carried out over a period of 6 months using purposive sampling, after obtaining clearance from the institutional ethics committee and informed consent from patient attenders;. 150 patients were recruited for the study. Patients aged above 18 years of either sex, admitted or transferred to the MICU and prescribed with antimicrobials were included, while those whose attenders did not consent, with insufficient data on antibiotic initiation, a stay of less than 48 hours, discontinuation of antimicrobials due to negative cultures, or resolution of infection signs within 48 hours were excluded; the study was conducted in three phases—Pre implementation, Implementation, and Post implementation phases. Where Pre and post implementation are carried out for duration of 3 months each and implementation phase for 1 month., during which medical records were reviewed to collect demographic data, comorbidities, lab and culture reports, antibiotic usage, and clinical outcomes, and during the observational phase, antimicrobial prescriptions were evaluated for appropriateness without any recommendations, followed by an intervention phase where recommendations based on guidelines were provided to the ICU team, and then a Post implementation phase where antibiotic appropriateness was reassessed without further intervention to evaluate sustained behavioural changes; a WHO-based antimicrobial stewardship questionnaire, modified to reflect current trends, was used at the bedside for documentation of antimicrobial-related data, with outcomes assessed in terms of days of therapy (DOT) per 1,000 patient days, mean ICU stay, total hospital stay, number of antimicrobials used per person, and percentage of appropriate prescriptions in pre implementation phase and Post implementation phases, while mortality and adverse drug reactions were also recorded, and all results were tabulated and analysed using appropriate statistical methods.

This study was conducted among 150 eligible study patients from the association of sociodemographic factors, clinical presentation, and insights into the antibiotic prescription practices in a large tertiary-care teaching hospital. Gender-wise distribution of study subjects depicts male predominance (53.3%). While male patients of age group, 19–40 years (42.5%) was slightly higher than female patients (30%) but female patients of 41 – 60 years and >60 years were more than male patients respectively 44.2% and 25.7% (Table 1). Table 1: Gender and Age wise distribution of the patients 19-40 yrs 41-60 yrs >60 yrs Total Male 34 (42.5%) 26 (32.5%) 20 (25%) 80 (53.3%) Female 21 (30%) 31 (44.2%) 18 (25.7%) 70 (46.6%) Majority of the study patients were diagnosed with CKD(Chronic kidney disease) with volume overload urosepsis (8%) and NS1(Non-structural protein 1) positive with thrombocytopenia (7.3%), followed by Acute exacerbation of Bronchial asthma (5.3%), Acute GE with AKI(Acute kidney injury) in seps is (2.6%), Acute GE(Gastroenteritis) with AKI in septic shock (6%), Acute GE with hyponatremia (0.6%), Acute Pancreatitis (2%), Acute Pancreatitis with sepsis (1.3%), AIDP (5.3%), Aspiration pneumonitis (2%), Bacterial Meningitis (2.6%), Bronchitis with acute exacerbation of COPD (4%), Bronchopneumonia (6.6%), CLD(Chronic liver disease) with aspiration pneumonia (4.6%), CLD with portal hypertension (2%), CVA(Cerebrovascular accident) (2.6%), CVA with sepsis (0.6%), DKA(Diabetic Ketoacidosis) (1.3%), DKA with AKI (0.6%), DKA in shock (1.3%), Meningitis (4%), OP(Organophosphorus) Compound poisoning with aspiration pneumonia (6.6%), Paraquat poisoning (6%), Pyelonephritis (2.6%), Snake bite (2.6%), Urosepsis in septic shock (4%), Hepatic encephalopathy (2%), Liver cirrhosis (1.3%), Viral fever with thrombocytopenia (3.3%). (Fig. 1). Table 2: Effect of Stewardship Interventions on Antibiotic Utilization Patterns Antibiotic prescribed DOT pre phase DOT/1000PD Pre phase DOT post phase DOT/1000PD post phase p Value Ceftriaxone 387 860 341 757.77 0.990 Piptaz 360 800 262 582.22 0.996 Meropenem 149 331.11 154 342.22 0.998 Ciprofloxacin 191 424.44 155 344.44 0.998 Metronidazole 171 380 91 202.22 0.994 Doxycycline 29 64.44 52 115.55 0.993 Azithromycin 115 255.55 73 162.22 0.996 Total 200 445.07 161 358.09 0.996 Table 3: Impact of Antimicrobial Stewardship Pre Post p Value De-escalation yes 09 (12%) 18 (24%) 0.089 no 66 (88%) 57 (76%) Escalation yes 62 (82.6%) 74 (98.6%) 0.0007 no 13 (17.3%) 01 (1.3%) Culture and Sensitivity yes 07 (9.4%) 18 (24%) 0.015 no 68 (90.6%) 57 (76%) Outcome Shift to ward 66 (88%) 73 (97.3%) 0.028 Death 9 (12%) 2 (2.7%)

Antibiotics are frequently prescribed to treat bacterial illnesses. Prescriptions should be reviewed and drugs should be prescribed sensibly to boost therapeutic efficacy and reduce drug-related side effects. Our study has a total of 150 patients and did a Pre implementation phase for 3 months, demographic feature of our patients are depicted in table 1 which summarizes 150 patients, males constituted 53.3% and females 46.6%. In the male group, the majority were aged 19–40 years (42.5%), followed by 41–60 years (32.5%), and >60 years (25%). In the female group, the largest proportion were 41–60 years (44.2%), followed by 19–40 years (30%), and >60 years (25.7%). This distribution suggests that middle-aged individuals (41–60 years) formed a significant portion of both genders, highlighting a potentially vulnerable demographic for the study's focus (e.g., infection risk, antibiotic use). Our study participant’s demographic features line with the study conducted by Tarun, S et al, which depicts study 63% male & 37% female among 100 participants and majority of the participants belong to age group of 41to 60 years [8]. Compared to Drupad HS et al study, among 202 patients maximum were male 110 and rest were female. [7] Table 2 depicts the frequency distribution of disease patterns among which majority of the study patients were diagnosed with CKD with volume overload urosepsis (8%) and NS1 +ve with thrombocytopenia (7.3%), compared to other studies like Drupad HS et al there were variety of cases admitted in the ICU among which respiratory tract infection (RTI) was most common (33.2%) followed by febrile illness (15.3%) and poisoning (15.3%). Priscilla Rupali et al, conducted study in Medical and Surgical ICU and found infectious cause alone accounted for 21.4% of cases. Non-infectious causes accounted for 29.9% of cases, and the remaining cases (48.7%) were a combination of both. Among the infectious causes in Medical ICU respiratory infection (10.7%) cases followed by urinary tract infection (5.2%) cases were significantly high [9]. Manjusha et al. did a study on medicine in patient department and found majority of the study IPD patients were diagnosed with respiratory (12.0%) followed by cystitis, urinary tract infection (10.7%). [1] Impact of antimicrobial stewardship interventions by comparing key outcome indicators between the pre-implementation and post-implementation phases explained in Figure 2. Length of Therapy (LOT), Days of Therapy (DOT), and DOT per 1,000 Patient Days (DOT/1000PD). Across all indicators, a reduction was observed in the post-implementation phase. DOT decreased from 1434 to 1136, LOT reduced from 781 to 638, and DOT/1000PD declined from 3175.24 to 2524.14, suggesting improved antibiotic utilization following the stewardship measures. Our study is in line with the study conducted by Priscilla Rupali et al, The primary outcome, DOT per 1,000patient days for study antimicrobials was 831.5 in the baseline phase compared to intervention phase which was significantly lower at 717.0 [9]. Compared to the study conducted by Aryal et al. where the study period was 3 years and DOT/1000PD were compared between these 3 years which was 324.20 in 2018, 446.45 in 2019, and 564.25 in 2020. [2] From our study results reduction in DOT and DOT/1000PD was observed in Table 2 for most antibiotics post-implementation, including ceftriaxone, piperacillin-tazobactam (Piptaz), ciprofloxacin, metronidazole, and azithromycin, indicating a decline in overall antibiotic usage. However, meropenem and doxycycline showed a slight increase in DOT post-implementation. Despite these variations, the p-values for all antibiotics were above 0.05, indicating that the observed differences were not statistically significant. Most commonly prescribed antibiotics are Ceftriaxone followed by piperacillin-tazobactam in both phases. On comparing to other studies, Manjusha et al. study depicts piperacillin + tazobactam (13.3%), followed by ceftriaxone/+sulbactam (10.5%) was most commonly used [1]. According to Aryal et al. piperacillin/ tazobactam 57.89 DOT/1000 PD followed by azithromycin had 53.98 are commonly prescribed antibiotics [2]. Asper Drupad HS et al Ceftriaxone (43.1%) and cefixime (38.6%) were the most commonly prescribed antibiotics. [7] The bar graph in figure3 compares the patterns of antimicrobial therapy choice between pre- and post-intervention phases of an antimicrobial stewardship program. A notable decrease is observed in empirical (E) therapy (from 38 to 25 cases), suggesting a reduction in reliance on broad-spectrum initial treatment. However, the combination of empirical and lab-based therapy (E+L) increased significantly from 15 to 35, indicating a positive shift toward using empirical therapy initially followed by culture-guided optimization — a key goal of stewardship efforts. Our study results are in line with the study by Manjusha et al. where empirical based treatment is more preferred than other modalities [1]. The table 3 presents the effect of implementing an antimicrobial stewardship program (ASP) on key clinical practices and outcomes. Post-intervention, de-escalation of antibiotics improved from 12% to 24%, though not statistically significant (p = 0.089). A significant increase in escalation rates was observed (82.6% to 98.6%, p = 0.0007), possibly reflecting more appropriate and timely adjustments based on clinical need. The use of culture and sensitivity (C&S) testing significantly increased from 9.4% to 24% (p = 0.015), indicating improved microbiological diagnostics to guide therapy. Most notably, clinical outcomes improved, with a significant increase in patients shifting towards (88% to 97.3%) and a reduction in mortality from 12% to 2.7% (p = 0.028). These findings support the effectiveness of ASP in promoting rational antibiotic use and enhancing patient recovery. Which is unique in our study where no other studies has explored the following parameters so deeply. Antimicrobial stewardship can provide all practitioners with tools to stop the overuse of valuable resources and help control the rise in AMR. The study's strengths include its prospective design, real-world ICU setting, use of a WHO-based tool, and inclusion of pre- and post- implementation phases. It measured multiple clinical outcomes, showed improved patient recovery and reduced mortality, and promoted culture-guided antibiotic use. However, it was limited by being a single-centre study with a small sample size, short duration, non-randomized design, and lack of resistance or cost data. Escalation rates increased post- implementation, and clinician adherence to recommendations was not assessed.

This prospective observational study highlights the significant impact of implementing antimicrobial stewardship practices in a tertiary care hospital MICU. Post- implementation, a reduction in days of therapy, DOT/1000 patient days, and empirical antibiotic use was observed, alongside improved clinical outcomes including reduced mortality and increased ward transfers. Enhanced use of culture and sensitivity testing and appropriate antibiotic escalation further demonstrate the effectiveness of stewardship interventions. Despite limitations such as the single-centre design and short study duration, the findings support the need for structured, guideline-based antimicrobial stewardship programs to promote rational antibiotic use, curb antimicrobial resistance, and improve patient care in critical care settings

1. NATH MANJUSHA, SHARMA DEEPAK, and NATH SOM. “ASSESSMENT OF ANTIBIOTIC STEWARDSHIP IN TERTIARY HEALTH CARE TEACHING MEDICAL INSTITUTION IN CENTRAL INDIA”. Asian Journal of Pharmaceutical and Clinical Research, vol. 17, no. 11, Nov. 2024, pp. 200-6, 2. Aryal , S. ., Joshi, M., Gupta, M., Uprety, B. N., Shrestha, R. K., Shah, P., & Rajbhandari, P. (2025). Utilization of Antimicrobial Agents in Intensive Care Units of Tertiary Care Hospital: An Observational Study. Journal of Nepal Medical Association, 63(284), 222–228. 3. Son NT, Thanh Tra T, Ngoc Thao PT (2017) Antimicrobial Stewardship Program at a tertiary teaching hospital in Vietnam: A longitudinal observational study. Clin Microbi ol Infect Dis, 2: 4. Baubie K, Shaughnessy C, Kostiuk L, et al. Evaluating antibiotic stewardship in a tertiary care hospital in Kerala, India: a qualitative interview study. BMJ Open 2019;9:e026193. 5. Luyt CE, Bréchot N, Trouillet JL, Chastre J. Antibiotic stewardship in the intensive care unit. Crit Care. 2014 Aug 13;18(5):480. 6. Ture Z, Güner R, Alp E. Antimicrobial stewardship in the intensive care unit. J Intensive Med. 2022 Nov 15;3(3):244-253. 7. HS, Drupad & H, Nagabushan & GM, Prakash. (2016). Prospective and observational study of antimicrobial drug utilization in medical intensive care unit in a tertiary care teaching hospital. International Journal of Pharmacological Research. 6. 10.7439/ijpr.v6i1.2886. 8. Tarun, S., Kapil, S., Amit, N., Gaurav, J., Munawwar, H., Gurvinder, S., Maheipeube, N., Malik, A., & Bimal, A. (2022). Assessment of antimicrobial drugs utilization in tertiary care hospital-an antimicrobial stewardship implication. International Journal of Health Sciences, 6(S7), 5474-5483. 9. Rupali P, et al. (2019). Impact of an antimicrobial stewardship intervention in India: Evaluation of post-prescription review and feedback as a method of promoting optimal antimicrobial use in the intensive care units of a tertiary-care hospital. Infection Control & Hospital Epidemiology, 40: 512–519,