Ventilator-associated pneumonia (VAP) is defined as pneumonia occurring more than 48 hours after endotracheal intubation and the initiation of mechanical ventilation. VAP represents one of the commonest healthcare-associated infections in intensive care settings and is associated with substantial morbidity, prolonged length of stay, increased antibiotic consumption and higher healthcare costs. In paediatric and neonatal populations VAP diagnosis and prevention pose unique challenges because of age-related differences in anatomy, physiology and device management. [1] Incidence estimates of VAP in the paediatric intensive care unit (PICU) vary widely across settings (reported between <2 to >60 episodes per 1,000 ventilator days or 2–35% of ventilated patients in various series), reflecting differences in case definitions, surveillance methods, patient-mix, resources and diagnostic practices. The proportion of ventilated patients who develop VAP is influenced by the number of ventilator days—longer ventilation durations are linked to higher cumulative incidence—and by local infection-control practices and antimicrobial use patterns. These wide variations underscore the need for centre-specific surveillance to guide empirical therapy and prevention strategies. [2] Paediatric-specific risk factors differ from adults in several ways. Historically, preference for uncuffed endotracheal tubes in small children increased the risk of micro aspiration and circuit leaks; more recent adoption of appropriately used cuffed tubes, cuff-pressure monitoring and subglottic suction devices has reduced, but not eliminated, aspiration-related risk. Other modifiable risk factors include enteral feeding practices, acid-suppression therapy, suboptimal oral hygiene, inadequate hand hygiene by staff, frequent circuit disconnections, and re-intubation episodes. Non-modifiable contributors include underlying neurological, cardiac, or genetic conditions that prolong mechanical ventilation and impair airway protective reflexes. [2] Microbiology of VAP in children is dominated by Gram-negative bacilli and Staphylococcus aureus, though the relative predominance of organisms varies by unit and by whether VAP is early- or late-onset. Early-onset VAP commonly implicates community-associated organisms (e.g., Streptococcus pneumoniae, H. influenzae, S. aureus), while late-onset VAP more frequently involves hospital-adapted and often multi-drug resistant (MDR) organisms such as Pseudomonas aeruginosa, Acinetobacter spp. and Enterobacteriaceae (Klebsiella, Enterobacter, Escherichia coli). The increasing prevalence of MDR Gram negative pathogens in many tertiary-care PICUs and NICUs complicates empiric antibiotic selection and heightens the necessity for up-to-date unit-level antibiograms. [3] Accurate and timely diagnosis is essential for better outcomes but remains problematic because there is no universally accepted gold-standard diagnostic test in paediatrics. Diagnostic approaches combine clinical criteria (new infiltrate on imaging with respiratory decline and inflammatory signs), quantitative or semi-quantitative lower respiratory tract cultures, and increasingly rapid molecular tests and biomarkers to inform early decision-making. The balance between prompt empiric therapy to prevent deterioration and antimicrobial stewardship to limit selection pressure requires knowledge of local epidemiology and judicious use of diagnostics such as tracheal aspirates, bronchoalveolar lavage (when indicated), PCR panels and biomarkers like procalcitonin. [3] Prevention strategies—often implemented as a bundle of evidence-informed practices—are central to reducing VAP burden. Core elements shown to reduce VAP incidence in various settings include strict hand hygiene, elevation of the head-of-bed, oral hygiene (including antiseptic mouthwash where appropriate), maintenance of appropriate cuff pressure and subglottic suctioning when available, minimizing circuit breaks and ventilator days, and early assessment for readiness to extubate. Educational programs, multidisciplinary task forces and adherence auditing reinforce compliance and have been associated with sustained reductions in VAP rates. Given paediatric-specific evidence gaps, adaptation of adult-derived elements to local paediatric practice and constant evaluation of bundle components is necessary. [4] Taken together, these considerations justify systematic, centre-level surveillance and reporting of the microbiology and antimicrobial susceptibility patterns of organisms isolated from ventilated paediatric patients. This information is critical to inform empiric antibiotic policies, prioritize infection-control measures, and support antimicrobial stewardship efforts targeted at preserving effectiveness of last-line agents while optimizing patient outcomes. Aims and Objectives To determine antimicrobial resistance of bacterial isolates from respiratory secretions of ventilated patients in PICU and NICU of a tertiary care centre

Retrospective observational study at Pediatric ICU (PICU) and Neonatal ICU (NICU) of a tertiary care hospital in Indore for Two years from April 2020 to March 2022. Admitted in NICU and PICU (0-15yrs) and ventilated at least for 48 hours were included. The data including demographic, laboratory and treatment given and outcome was collected from medical records ET secretion was collected with all aseptic precautions and sent for culture sensitivity of those patients who developed new onset fever spike and suspected VAP VAP was defined using CPIS score of more than 6. The Clinical Pulmonary Infection Score (CPIS) was developed to serve as a surrogate tool to facilitate the diagnosis of ventilator-associated pneumonia (VAP) .A CPIS >6 may correlate with VAP. Significant growth was considered when >105 colonies were obtained from tracheal secretions[5] The antibiotic susceptibility of these clinical isolates were determined by the Kirby‑Bauer disk diffusion method [6] MDR organisms- In our study, multidrug resistance (MDR) definition for Gram‑negative organisms was taken as non‑susceptible to more than one agent in at least 3 antimicrobial categories. Staphylococcus was considered as MDR if (i) it was methicillin‑resistant and (ii) non‑susceptible to more than one agent in atleast 3 antimicrobial categories.[7] During the study period there were a total of 253 (PICU(158)+NICU(95) ) ventilated patients , out of which 113 were ventilated for >48 hrs and hence were eligible for study. Patients ventilated for <48hrs were 148 which got excluded from study. ET Secretions showed significant growth in 41 samples isolated from 39 patients indicating the culture positivity rate = 46% and 9 patients out of 39 Developed VAP as per their CPIS Score >6 PICU(5) + NICU(4)

Table 1. Demographic profile of 39 patients enrolled in the study Total patients enrolled n=39 Median Age 4 years (0 – 15 years) M:F 1.4:1 NICU patients 5 PICU Patients 34 Table 2. Ventilation Statistics VAP Rate per 1000 ventilatory days 23.74 Most common pathogens in PICU Klebsiella and Pseudomonas Most common pathogens in NICU Acinetobacter and Klebsiella Table 3. Antimicrobial susceptibility profile of the pathogens a. Antibiotic resistance of Gram‑negative organisms from 39 patients enrolled in the study Antibiotics Percentage resistance to Enterobacteriaceae n=15 Percentage resistance to P. aeruginosa n=6 Percentage resistance to Acinetobacter spp. n=5 Amikacin 26.66% 0% 80% Ampiciilin 93.33% 100% 100% Amoxy-clav 86.66% 100% 100% Ceftazidime 53.33% 50% 80% Ceftriaxone 73.33% 33.33% 80% Cefotaxime 66.66% 66% 80% Cefepime 33.33% 16% 80% Cefoxitine 53.33% 83% 80% Cefoperazone 53.33% 50% 80% Cefuroxime 66.66% 50% 100% Cephaloridine 66.66% 100% 80% Ciprofloxacin 26.66% 16% 80% Imepenem 6.66% 33% 60% Meropenem 6.66% 16% 60% Ertapenem 60% 83% 100% Piperacillin and Tazobactam 20% 0% 80% Cotrimoxazole 40% 66% 80% Chloramphenicol 6.66% 83% 80% Polymixin –B 0% 0% 0% Colistin 6.66% 16% 40% Clindamycin 13.33% 16% - Gentamicin 53.33% 16% 80% Netilmycin 33.33% 0% 80% Cefoperazone + Sulbactam 20% 0% 40% b. Antibiotic resistance of Staphylococcus spp. isolated from 39 patients enrolled in the study Antibiotics Percentage resistance n=7 Penicillin - G 57.14% Cefoxitin 42.85% Oxacillin 57.14% Erythromycin 71.42% Clindamycin 42.85% Chloramphenicol 0% Cotrimoxazole 71.42% Ciprofloxacin 28.57% Gentamicin 14.28% Vancomycin 0% Linezolid 0% Teicoplanin 0% Cefoperazone + Sulbactam 14.28% Amikacin 0% Ampicillin 71.42% Amoxyclav 42.85% Table 4. Outcomes of patients included in the study group Outcome Total no. of patients Discharge 70% (27) DAMA 18% (7) Death 12%(5)

In this retrospective observational study of ventilated pediatric and neonatal patients, we found a high rate of colonization of the endotracheal tract by potentially pathogenic bacteria, with a predominance of multidrug-resistant (MDR) organisms. Of the 42 pathogens isolated from 39 patients, 31 (73.8%) were MDR, and the most frequently encountered organisms in the PICU were Klebsiella and Pseudomonas, while Acinetobacter and Klebsiella predominated in the NICU. The overall culture-positivity rate was 46% and the observed VAP rate was 23.74 per 1,000 ventilator days. Outcomes in the cohort showed 70% discharges, 18% DAMA, and 12% mortality. Ventilator-associated colonization and subsequent VAP remain major problems in intensive care units worldwide. Our findings of mainly Gram-negative predominance and high MDR rates echo the pattern reported in earlier series from tertiary centres, which have also reported non-fermenters (such as Pseudomonas and Acinetobacter) and Enterobacteriaceae as the common organisms in ventilated patients. The original multi-specialty hospital study reported Pseudomonas, Acinetobacter and Klebsiella as major isolates and an overall high proportion of MDR strains, reinforcing that ICU flora frequently consists of organisms with extensive antimicrobial resistance.[8] The VAP rate in our study (23.74/1,000 ventilator days) is higher than that reported in some adult ICU series and higher than the 11.5/1,000 ventilator days reported in the comparison study[9], although direct comparison is limited by differences in patient population (pediatric/neonatal vs. adult), study design, surveillance definitions and local practices. Several factors may drive a higher VAP rate in our cohort: the pediatric population’s unique susceptibility, different patterns of device care, and local antibiotic pressure leading to colonization by MDR organisms. These observations underscore the importance of center-specific surveillance to guide empirical therapy and prevention strategies. The high proportion of MDR isolates (73.8% of isolates in our study) is concerning from both therapeutic and infection-control standpoints. MDR rates in our cohort are comparable to other Indian tertiary-centre reports which have documented large proportions of isolates resistant to beta-lactams and other commonly used agents. In our data, resistance to commonly used penicillins, cephalosporins and fluoroquinolones was substantial; carbapenem resistance was present but variable across organisms. The persistence of susceptibility to polymyxins/colistin for many non-fermenters suggests these agents remain last-line options; however, reliance on such agents is undesirable because of toxicity and the risk of emerging resistance. The local antibiogram produced by this study should therefore inform empirical regimens while stewardship efforts aim to preserve higher-end agents. Our findings have direct implications for empirical antibiotic policies in PICU and NICU settings. Given the frequent recovery of MDR Klebsiella, Pseudomonas and Acinetobacter, empirical regimens guided solely by older first-line agents may fail. Empirical choices should be based on up-to-date unit-specific antibiograms, with early de-escalation guided by culture results. Simultaneously, strict infection control measures, adherence to VAP-prevention bundles (head-of-bed elevation, oral hygiene, subglottic suctioning where feasible, sedation minimization and early extubation), and routine surveillance cultures when indicated, are essential to curb colonization and subsequent infection. Limitations The limitation of the study is that it is of short duration and is from a single tertiary care center of a semi‑urban population The microbiological profile thus reflects local environment and cannot be generalized to other health care settings More such studies of longer durations and involving multiple centers can be helpful in making generalized recommendations

To conclude, we found that colonizing organism mainly consisted of MDR bacteria which later can be the etiological agents of VAP in these patients The implementation of rational protocols for the use of empirical antibacterial agents, based on the knowledge of local microbiological patterns, rapid delivery of results of culture and susceptibility assays are essential strategies, which coupled with strict infection control practices and regular application of VAP bundle may help in decreasing VAP‑related mortality rates and morbidity by MDR bacteria in the ICUs The antibiotic susceptibility pattern of these isolates will help the clinicians to choose the appropriate antimicrobial agents.

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