Healthcare-associated infections (HAIs) are defined as infections that develop 48 hours or more after hospital admission, up to 30 days following discharge, and up to one year in patients with implanted devices. These infections are neither present nor incubating at the time of admission and continue to represent a major challenge to patient safety worldwide. ¹ Device-associated healthcare-associated infections (DA-HAIs), particularly ventilator-associated pneumonia (VAP), central line–associated bloodstream infections (CLABSI), and catheter-associated urinary tract infections (CAUTI), constitute the most frequent HAIs in intensive care units (ICUs). These infections are associated with significant morbidity and mortality across diverse healthcare settings and are major contributors to adverse patient outcomes. ² Patients admitted to ICUs are especially vulnerable due to the presence of multiple comorbidities and frequent exposure to invasive devices such as mechanical ventilators, central venous catheters, urinary catheters, inotropic support, and parenteral nutrition. ³ The ICU environment also serves as a reservoir for multidrug-resistant (MDR) organisms, which contribute to opportunistic infections, particularly in the presence of invasive devices. DA-HAIs are a leading cause of bacteremia and sepsis and are associated with prolonged hospital stay, increased need for isolation and barrier nursing, higher healthcare costs, increased morbidity and mortality, and reduced availability of ICU beds. ⁴˒⁵. The rising incidence of HAIs caused by MDR pathogens poses an additional challenge due to limited therapeutic options and a declining pipeline of new antimicrobial agents. ⁶ The incidence of DA-HAIs is influenced by several factors, including the frequency and duration of device use, adherence to infection prevention and control practices, ICU infrastructure, and the immune status of patients. Globally, the burden of HAIs is disproportionately higher in low- and middle-income countries (LMICs), where HAI rates are reported to be 2–10 times higher than those in high-income countries, where ICU HAI rates range from 5% to 10%. Furthermore, HAI rates vary between hospitals, among different ICUs within the same institution, and over time within the same ICU, with teaching and tertiary care hospitals generally reporting higher rates. ⁷ Given the significant clinical and economic impact of DA-HAIs, continuous surveillance is essential to understand local epidemiology, monitor trends, and evaluate the effectiveness of infection prevention and control strategies. This study was undertaken to assess the burden and patterns of device-associated healthcare-associated infections in the intensive care unit of a tertiary care government hospital in Sikkim. OBJECTIVES Primary Objectives 1. To determine the burden of device-associated healthcare-associated infections (DA-HAIs) in the intensive care units of a tertiary care government hospital in Sikkim. 2. To identify the bacterial etiological agents responsible for device-associated healthcare-associated infections in the ICUs. Secondary Objective 1. To analyse the antimicrobial susceptibility patterns of bacterial isolates causing device-associated healthcare-associated infections.

Study Design and Setting This retrospective observational study was conducted in the intensive care units (ICUs) of Sir Thutob Namgyal Memorial Hospital, a 1,000-bed government tertiary care teaching hospital in Northeast India. The study included data from January 2022 to December 2023 and aimed to assess the burden, microbiological profile, and trends of device-associated healthcare-associated infections (DA-HAIs). Data were retrospectively retrieved from ICU infection surveillance records, microbiology laboratory reports, and hospital infection control databases after completion of the study period. No patient recruitment, real-time follow-up, or intervention was undertaken specifically for the purpose of this study. During the study period, the hospital underwent major infrastructural expansion from a 300-bed facility to a newly commissioned 1,000-bed hospital. In addition, ICU services expanded from a single ICU to separate central, medical, and trauma ICUs. Strengthening of in-house microbiological diagnostic facilities also occurred during this period. Surveillance Methodology Routine surveillance of device-associated healthcare-associated infections (DA-HAIs) was carried out by the Infection Control Team (ICT) under the supervision of the Hospital Infection Control Committee (HICC) as part of standard hospital infection prevention and control activities. Surveillance was performed using standard definitions and methodologies recommended by the Centers for Disease Control and Prevention National Healthcare Safety Network (CDC-NHSN). The surveillance records included clinical, microbiological, and environmental monitoring data from the ICUs, which were retrospectively reviewed and analyzed for the present study. Clinical Surveillance As part of routine infection control surveillance practices in the ICUs, clinical data were recorded during daily morning ICU rounds by the Infection Control Team. The surveillance records included patient demographics, date of ICU admission, primary diagnosis, presence of fever or hypothermia, abnormal leukocyte counts, use and duration of invasive devices (urinary catheter, mechanical ventilator, and central venous catheter), and patient outcomes such as transfer, discharge, or death. These records were retrospectively reviewed and analysed for the present study. Laboratory Surveillance As part of routine hospital infection surveillance, appropriate clinical specimens were collected from ICU patients who developed signs and symptoms suggestive of healthcare-associated infection (HAI) after at least 48 hours of device use. Specimens included paired blood cultures, urine samples collected from urinary catheters after clamping, and endotracheal aspirates. Laboratory processing records showed that samples were aerobically incubated at 37°C for 24 hours on solid media. Bacterial identification had been performed using colony morphology, Gram staining, motility testing, and conventional biochemical methods. Antimicrobial susceptibility testing was carried out according to 2022 guidelines of the Clinical and Laboratory Standards Institute (CLSI). Quality control procedures were maintained using standard reference strains including Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, and Pseudomonas aeruginosa ATCC 27853. Laboratory surveillance records were retrospectively reviewed for the present study. Definitions of Device-Associated Infections Ventilator-Associated Pneumonia (VAP) was diagnosed in mechanically ventilated patients with a positive endotracheal aspirate culture, along with at least one CDC-defined clinical criterion, including new onset or change in character of purulent sputum, isolation of a pathogen from blood, or radiological evidence of new, persistent, or progressive infiltrates, consolidation, cavitation, or pleural effusion. Supporting clinical features included fever (>38°C) or hypothermia, leucocytosis (>10,000/mm³) or leukopenia, presence of ≥25 neutrophils and ≥5% cells with intracellular bacteria on Gram stain, and quantitative growth ≥10⁵ colony-forming units (CFU)/mL after dilution. Central Line–Associated Bloodstream Infection (CLABSI) was diagnosed when paired blood cultures obtained simultaneously from a central line and a peripheral vein after at least 48 hours of catheterization yielded the same pathogen, with the central line culture demonstrating significant growth (>10⁵ CFU) at least two hours earlier than the peripheral culture. The diagnosis was made only in the absence of an alternative identifiable source of infection. In cases of coagulase-negative Staphylococcus, CLABSI was diagnosed only when the organism was isolated within 48 hours in the presence of compatible clinical features. Catheter-Associated Urinary Tract Infection (CAUTI) was diagnosed when a urine specimen collected from a patient with an indwelling urinary catheter, or within seven days of catheter removal, yielded no more than two uropathogens at concentrations ≥10⁵ CFU/mL, accompanied by relevant clinical features such as fever (>38°C), suprapubic tenderness, urinary urgency, or positive dipstick findings. Supportive evidence included pyuria (≥10 leukocytes/mL), presence of organisms on Gram stain, documented clinical diagnosis of UTI, or initiation of antimicrobial therapy for UTI. Outcome Measures Device utilization ratio (DUR) and infection rates were calculated using standard formulae: • Device Utilization Ratio (DUR) = Number of device-days / Number of patient-days • CAUTI rate = (Number of CAUTI cases / Total catheter-days) × 1,000 • VAP rate = (Number of VAP cases / Total ventilator-days) × 1,000 • CLABSI rate = (Number of CLABSI cases / Total central line-days) × 1,000 • In addition, regular on-site training sessions and demonstrations on infection prevention and control practices, standard precautions, and biomedical waste management had been routinely conducted for nursing staff, medical attendants, and housekeeping personnel as part of ongoing hospital infection control activities. Data Review and Feedback As part of routine hospital infection control activities, surveillance data had been compiled and presented quarterly during meetings of the Hospital Infection Control Committee (HICC), attended by the Medical Superintendent, Heads of Departments, and representatives from medical stores and logistics. Recommendations arising from these meetings were routinely communicated to the concerned departments, and records of their implementation and follow-up review were retrospectively analyzed for the present study.

Study Population and HAI Distribution A total of 56 microbiologically confirmed device-associated healthcare-associated infection (HAI) episodes were identified during the study period. The mean age of the study participants was 60.19 ± 17.07 years. Male patients constituted a higher proportion of cases compared to females. Among the HAIs, catheter-associated urinary tract infection (CAUTI) was the most common, accounting for 42 cases (75%), followed by central line-associated bloodstream infection (CLABSI) and ventilator-associated pneumonia (VAP) with 7 cases (12.5%) each. DA-HAI rate was found to be 4.47%. Among which catheter-associated urinary tract infection (CAUTI) was the most common, accounting for 42 cases (75%), followed by central line-associated bloodstream infection (CLABSI) and ventilator-associated pneumonia (VAP) with 7 cases (12.5%) each. The total device utilization days over 12 months was 12,505, with a monthly average of 1,042.08 +120.9 (95% CI 965.2 to 1118.9). The Pooled Average Device Utilization Ratio (DUR) over the 12-month period is 1.08 (Urinary catheter 0.724, central line 0.195 and ventilator 0.165) The total urinary catheter days during the study period were 8,354, with a monthly mean urinary catheter utilization of 696 ± 26 days (95% CI: 644.45–747.89). The urinary catheter utilization ratio was 0.72 ± 0.008 (95% CI: 0.708–0.740). The total central line days during the study period were 2,250, with a monthly mean central line utilization of 187.5 ± 13.7 days (95% CI: 160.7–214.3). The central line utilization ratio was 0.195 ± 0.004 (95% CI: 0.188–0.202). The total ventilator days during the study period were 1,901, with a monthly mean ventilator utilization of 158.4 ± 12.6 days (95% CI: 133.7–183.1). The ventilator utilization ratio was 0.165 ± 0.003 (95% CI: 0.158–0.172). The total episode of DA-HAI, mean monthly episodes and rates were 56, 4.7 ± 2.2 (95% CI 0.4–9.0) and 4.48 (95% CI 3.31-5.65). Total CAUTI episodes, mean monthly CAUTI episodes and rate were 42 (75 % of DA-HAI), 3.5 ± 1.9 (95% CI: 0–7.2) and 5.03 per 1000 urinary catheter days (95% CI 3.51–6.55) respectively Total CLABSI episodes, mean monthly CLABSI episodes, CLABSI rate were 7, 0.58 ± 0.76 (95% CI: 0–2.07), 3.11 per 1,000 central line–days (95% CI: 0.80–5.42) respectively Total VAP episodes, mean monthly VAP episodes, VAP rate were 7, and 0.58 ± 0.76 episodes/month (95% CI: 0–2.07) and 3.68 per 1,000 ventilator-days (95% CI: 0.95–6.41) respectively Microbiological Profile Gram-negative organisms predominated, accounting for the majority of isolates recovered from healthcare-associated infections. Escherichia coli was the most frequently isolated pathogen (13 isolates; 23.2%), followed by Enterococcus spp (11 isolates; 19.6%). Acinetobacter spp, Klebsiella pneumoniae, and Pseudomonas aeruginosa were isolated with equal frequency (10 isolates each; 17.9%). A single isolate of Proteus spp (1.8%) was identified. Catheter-associated urinary tract infections were primarily caused by E. coli, Enterococcus spp, and Klebsiella pneumoniae, whereas central line-associated bloodstream infections and ventilator-associated pneumonia were predominantly associated with non-fermenting Gram-negative bacilli, particularly Acinetobacter spp and Pseudomonas aeruginosa (Figure 2). CAUTI Isolates Escherichia coli isolates demonstrated high resistance to ceftriaxone, ciprofloxacin, and cotrimoxazole, with variable susceptibility to aminoglycosides. A significant proportion of isolates exhibited resistance to carbapenems, indicating the presence of extended-spectrum β-lactamase (ESBL) producing and carbapenem-resistant strains. Colistin susceptibility was preserved in most isolates where tested.Enterococcus spp isolates showed high resistance to ciprofloxacin, while linezolid demonstrated uniform susceptibility. Vancomycin susceptibility was retained in the majority of isolates, with no confirmed vancomycin-resistant enterococci detected.Klebsiella pneumoniae isolates displayed marked resistance to third-generation cephalosporins and fluoroquinolones, with frequent resistance to carbapenems. All tested isolates remained susceptible to colistin.Acinetobacter spp isolates causing CAUTI exhibited extensive multidrug resistance, including resistance to aminoglycosides, β-lactams, fluoroquinolones, and carbapenems. Colistin was uniformly effective against these isolates.Pseudomonas aeruginosa isolates demonstrated high resistance to ciprofloxacin, piperacillin-tazobactam, and carbapenems, with preserved susceptibility to colistin. CLABSI Isolates CLABSI episodes were mainly caused by Acinetobacter spp, Klebsiella pneumoniae, and Pseudomonas aeruginosa. These isolates showed universal resistance to third-generation cephalosporins and a high degree of carbapenem resistance. Colistin remained active against all Gram-negative isolates, while linezolid was effective against Gram-positive isolates. VAP Isolates VAP was predominantly associated with Acinetobacter spp, Klebsiella pneumoniae, and Pseudomonas aeruginosa. These organisms exhibited very high resistance to carbapenems and fluoroquinolones, indicating late-onset VAP with multidrug-resistant pathogens. Colistin demonstrated the highest susceptibility rates, emerging as the most reliable therapeutic option.

The present study provides two years of surveillance data on DA-HAIs from a tertiary-care government hospital in Sikkim. A total of 56 microbiologically confirmed DA-HAI episodes were identified during 12,505 device-days, with CAUTI accounting for 75%, followed by CLABSI and VAP (12.5% each). This is the first systematic surveillance of device-associated HAIs reported from a tertiary-care hospital in Sikkim, providing an important local benchmark for IPC practices. The findings are particularly relevant as the hospital underwent major expansion during the study period, from a 300-bed to a 1,000-bed facility, with critical-care services expanding from a single ICU to separate central, medical, and trauma ICUs. Strengthening of in-house microbiological diagnostic facilities also occurred during this period. These changes may have influenced patient volume, case mix, device utilization, clinical practices, and detection of HAIs. Nevertheless, this data will provide a valuable baseline for monitoring future trends and evaluating the impact of IPC interventions as services stabilize. In a multicentre Indian Healthcare Associated Infection Surveillance Network study by Mathur et al.², involving 26 tertiary-care hospitals and 89 ICUs, CAUTI rates varied across ICU types, with the highest rate of 4.5 per 1,000 urinary-catheter days reported in paediatric medical ICUs. In comparison, the present study showed a slightly higher rate of 5.03 per 1,000 urinary-catheter days. The CAUTI rate in the present study was also higher than the 2.1 per 1,000 catheter-days reported by Lohiya and Deotale⁸ from a tertiary-care hospital in Central India. The higher rate in our study was accompanied by greater urinary-catheter utilization (DUR, 0.724 vs. 0.53), suggesting that greater catheter exposure may have contributed to the higher infection burden. However, differences in duration of catheterization, catheter-maintenance practices, adherence to CAUTI-prevention measures, and surveillance methodology may also account for the observed variation. Similarly, the INICC 2015–2020 report⁹, based on a 6-year prospective cohort involving 204,770 patients across 45 countries, reported a CAUTI rate of 2.91 per 1,000 urinary-catheter days, which was lower than that observed in the present study. This relatively higher CAUTI rate in our setting highlights urinary-catheter utilization and catheter stewardship as important targets for continued IPC efforts, particularly daily assessment of catheter necessity and prompt removal when no longer indicated. The CLABSI rate in the present study was 3.11 per 1,000 central-line days, with a central-line utilization ratio (DUR) of 0.195. This was lower than rates reported in several Indian ICU studies. In the 7-year multicentre Indian surveillance study by Parveen et al.¹⁰, the CLABSI rate was 8.68 per 1,000 central-line days in adult ICUs, with a central-line utilization ratio of 0.38. Similarly, Lohiya and Deotale⁸ reported a rate of 10.6 per 1,000 central-line days in a tertiary-care ICU in Central India, while Maqbool and Sharma¹¹ reported 16.4 per 1,000 central-line days in a trauma ICU, with a higher DUR of 0.8. In comparison, the INICC 2015–2020 report⁹, based on prospective surveillance across 45 countries, reported a CLABSI rate of 4.55 per 1,000 central-line days. The relatively low CLABSI rate observed in the present study may partly reflect the low central-line utilization ratio (0.195), resulting in lower exposure to central venous catheters. Adherence to appropriate line insertion and maintenance practices, timely removal of unnecessary catheters, and hand-hygiene practices may also have contributed. However, these factors were not quantitatively assessed in the present study. In our study, the VAP rate was 3.68 per 1,000 ventilator-days, with a DUR of 0.165 and 1,901 ventilator-days. This rate was lower than the 13.4 per 1,000 ventilator-days reported by Lohiya and Deotale⁸ in a tertiary-care hospital in Central India and the 6.4 per 1,000 ventilator-days reported by Mathur et al.² in a multicentre Indian study. Mathur et al. reported a higher DUR of 0.30 compared with 0.165 in our study. The INICC multicountry surveillance report³ for 2015–2020 reported a pooled VAP rate of 11.96 per 1,000 MV-days, also substantially higher than our observed rate. The lower VAP rate observed in our ICU may reflect effective implementation of VAP prevention practices and lower exposure to mechanical ventilation. Continued surveillance of VAP and DUR is essential to sustain and further improve infection-prevention practices. Microbiological profile The predominance of Gram-negative organisms in the present study is consistent with the microbiological pattern reported from other Indian healthcare settings. However, the distribution varied according to the type of DA-HAI. The predominance of E. coli, Enterococcus spp., and K. pneumoniae in CAUTI is comparable to findings from the multicentre surveillance study by Mathur et al.² al., in which Enterococcus spp. and Escherichia spp. were among the common urinary pathogens. In contrast, Acinetobacter spp. and P. aeruginosa predominated in CLABSI and VAP in our study, consistent with the pathogen profile reported by Khan et al.⁴, where K. pneumoniae, E. coli, P. aeruginosa, and A. baumannii were the major DA-HAI pathogens. These findings highlight the continued importance of Gram-negative organisms in ICU-associated infections and the need for ongoing microbiological surveillance and appropriate antimicrobial stewardship. Antimicrobial susceptibility testing The present study demonstrated a high burden of antimicrobial resistance among DA-HAI isolates, particularly Gram-negative organisms. E. coli and K. pneumoniae causing CAUTI showed substantial resistance to third-generation cephalosporins, fluoroquinolones, and carbapenems, while Acinetobacter spp. and P. aeruginosa demonstrated extensive multidrug resistance. Similar high levels of carbapenem resistance among Klebsiella, E. coli, Acinetobacter, and Pseudomonas have been reported in the multicentre Indian surveillance study by Mathur et al.² and in other Indian ICU studies. The predominance of multidrug-resistant Gram-negative organisms in CLABSI and VAP in our study further reflects the challenges of antimicrobial therapy in critically ill patients. In particular, the high resistance to carbapenems and fluoroquinolones among Gram-negative pathogens is concerning, given their frequent use in critically ill patients. Colistin retained activity against all the multidrug-resistant Gram-negative isolates in the present study, similar to findings reported by Khan et al.⁴ However, colistin should be considered cautiously and reserved for appropriate indications because of its toxicity and the risk of emergence of resistance

The present study highlights the burden and microbiological profile of device-associated healthcare-associated infections in the ICUs of a tertiary care government hospital in Sikkim. CAUTI was the most common DA-HAI, and Gram-negative multidrug-resistant organisms, particularly Acinetobacter spp., Klebsiella pneumoniae, and Pseudomonas aeruginosa, were the predominant pathogens. Although the overall DA-HAI rates observed were comparatively lower than those reported from several Indian and international ICUs, the high prevalence of antimicrobial resistance remains a major concern. Continuous surveillance, strict adherence to infection prevention and control practices, rational antimicrobial stewardship, periodic staff training, and ongoing microbiological monitoring are essential to further reduce the burden of DA-HAIs and limit the spread of multidrug-resistant organisms in critical care settings.

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