Volume 32, Issue 1 (3-2025)
RJMS 2025, 32(1): 1-8 |
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Research code: 22687
Ethics code: IR.IUMS.FMD.REC.1402.325
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Jafari A, Zare Mahmoudabadi R, Montazer F, Vafapour M, Yousefzadegan S. Microbial Profile and Antimicrobial Susceptibility of Endotracheal Aspirate Isolates in Intubated Children Admitted to the Pediatric Intensive Care Unit: A Retrospective Study at Firouzabadi Hospital (2019–2021). RJMS 2025; 32 (1) :1-8
URL: http://rjms.iums.ac.ir/article-1-9152-en.html
URL: http://rjms.iums.ac.ir/article-1-9152-en.html
Abolfazl Jafari1 
, Ramin Zare Mahmoudabadi2 , Fatemeh Montazer3 , Maryam Vafapour4 , Sedigheh Yousefzadegan *5
, Ramin Zare Mahmoudabadi2 , Fatemeh Montazer3 , Maryam Vafapour4 , Sedigheh Yousefzadegan *5
1- Medical Student Medical Student, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
2- Assistant Professor Pediatric Intensivist, Assistant Professor, Department of Pediatrics, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran
3- Associate Professor Dermatopathologist, Associate Professor of Pathology, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran
4- Assistant Professor Pediatrician, Assistant Professor, Department of Pediatrics, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran
5- Assistant Professor Department of Pediatrics, Assistant Professor of Pediatric Pulmonology, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran ,dr.yousefzadegan@gmail.com
2- Assistant Professor Pediatric Intensivist, Assistant Professor, Department of Pediatrics, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran
3- Associate Professor Dermatopathologist, Associate Professor of Pathology, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran
4- Assistant Professor Pediatrician, Assistant Professor, Department of Pediatrics, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran
5- Assistant Professor Department of Pediatrics, Assistant Professor of Pediatric Pulmonology, Firoozabadi Clinical Research Development Unit (FACRDU), School of Medicine, Iran University of Medical Sciences, Tehran, Iran ,
Abstract: (404 Views)
Background & Aims: Healthcare-associated infections (HAIs) remain one of the major causes of morbidity, mortality, prolonged hospitalization, and increased healthcare costs in pediatric intensive care units (PICUs). Critically ill children who require endotracheal intubation and mechanical ventilation are particularly susceptible to respiratory tract colonization and subsequent nosocomial infections because of impaired airway defense mechanisms, prolonged hospitalization, frequent invasive procedures, and repeated exposure to broad-spectrum antimicrobial agents. Delayed initiation of appropriate antimicrobial therapy has been associated with unfavorable clinical outcomes, whereas timely empirical treatment based on local microbiological surveillance may substantially improve patient prognosis. Because the epidemiology of healthcare-associated pathogens and antimicrobial resistance patterns varies considerably among hospitals and even between intensive care units within the same institution, periodic surveillance of local microbial profiles is essential for developing evidence-based empirical antibiotic protocols. To date, no comprehensive evaluation of microorganisms isolated from endotracheal aspirate cultures had been performed in the PICU of Firouzabadi Hospital. Therefore, this study aimed to determine the frequency of pathogenic microorganisms isolated from positive endotracheal aspirate cultures in intubated pediatric patients, evaluate their antimicrobial susceptibility and resistance patterns, and provide local epidemiological data that may facilitate more appropriate empirical antimicrobial therapy, strengthen infection-control policies, and support antimicrobial stewardship programs.
Methods: This retrospective cross-sectional study was conducted after obtaining approval from the Ethics Committee of Iran University of Medical Sciences. The study population consisted of all intubated children admitted to the PICU of Firouzabadi Hospital between 2019 and 2021. Demographic and clinical information was extracted from the Hospital Information System (HIS) and patients' medical records using a standardized data collection checklist.
Collected variables included age, sex, cause of hospitalization, duration of hospital stay, microbiological findings of positive endotracheal aspirate cultures, and antimicrobial susceptibility results obtained from antibiograms. Age, sex, and admission diagnosis were considered independent variables, whereas duration of hospitalization, isolated microorganisms, and antimicrobial susceptibility patterns were considered outcome variables. Descriptive statistical analyses were performed using SPSS version 26. Associations between the type of isolated microorganism and duration of hospitalization were evaluated, and a p-value of less than 0.05 was considered statistically significant.
Results: A total of 78 intubated pediatric patients were included in the study. Among them, 44 (56.4%) were boys and 34 (43.6%) were girls. The mean age of the patients was 4.8 ± 0.5 years, with an age range extending from one month to sixteen years. Pneumonia was the leading cause of PICU admission (33.3%), followed by COVID-19 infection (24.4%) and seizure disorders (12.8%). The mean duration of hospitalization was 25.0 ± 31.8 days, ranging from 2 to 210 days. During the study period, 135 positive endotracheal aspirate cultures were identified from the 78 patients. The most frequently isolated microorganisms were Acinetobacter baumannii (19.3%), Klebsiella pneumoniae (17.8%), and Pseudomonas aeruginosa (14.8%). Other isolated pathogens included Streptococcus species, Enterobacter agglomerans, Staphylococcus aureus, Enterobacter cloacae, Escherichia coli, Enterobacter aerogenes, Candida albicans, and several less frequently encountered organisms.
Antimicrobial susceptibility testing demonstrated that the highest rates of susceptibility were observed for amikacin (20.0%), ciprofloxacin (19.3%), meropenem (14.1%), imipenem (13.3%), ceftazidime (12.6%), and piperacillin (11.9%). These findings suggest that these antimicrobial agents retained comparatively greater activity against the isolated pathogens in this PICU population. Among the tested antimicrobial agents, the highest rates of resistance were observed against ceftriaxone (72.6%), cefixime (68.9%), imipenem (60.7%), piperacillin (60.0%), ciprofloxacin (58.5%), amikacin (58.5%), ceftazidime (56.3%), and meropenem (52.6%). Although several antibiotics demonstrated relatively higher susceptibility rates, the overall resistance profile indicated a substantial burden of multidrug-resistant microorganisms among intubated children admitted to the PICU. Because this investigation was retrospective and antibiograms were not uniformly performed for every cultured isolate, microorganism-specific resistance patterns could not be analyzed reliably. A statistically significant association was observed between the duration of hospitalization and the isolated microorganism (correlation coefficient = –0.230, P < 0.001). The longest hospital stays were observed among patients with positive cultures for Enterobacter aerogenes (119.0 ± 5.3 days), followed by Escherichia coli (97.2 ± 3.7 days) and Enterobacter agglomerans (75.1 ± 6.6 days). These findings suggest that infections caused by relatively more resistant microorganisms may be associated with prolonged hospitalization. However, because of the retrospective nature of the study and the limited sample size, detailed subgroup analyses according to patients' age, underlying diagnosis, or other potential risk factors were not feasible.
Conclusion: Nosocomial infections remain a major challenge in pediatric intensive care units, where critically ill children are highly vulnerable to respiratory infections due to invasive procedures such as endotracheal intubation and mechanical ventilation. Early identification of local microbial epidemiology is essential for guiding empirical antimicrobial therapy before culture results become available. In this study, Acinetobacter baumannii, Klebsiella pneumoniae, and Pseudomonas aeruginosa were the most frequently isolated pathogens from positive endotracheal aspirate cultures. These organisms are well-known causes of healthcare-associated respiratory infections and are often associated with multidrug resistance. Their predominance highlights the importance of local microbiological surveillance in supporting evidence-based empirical treatment decisions. A high level of resistance was observed against several commonly used antibiotics, particularly third-generation cephalosporins and carbapenems, emphasizing the need for continuous monitoring of antimicrobial susceptibility patterns and implementation of antimicrobial stewardship programs. At the same time, the relatively higher susceptibility of certain agents may help clinicians select more appropriate initial therapy while awaiting definitive microbiological results. The association between specific microorganisms and prolonged hospitalization suggests that resistant pathogens may contribute to longer hospital stays and increased healthcare burden. Although causal relationships cannot be confirmed due to the retrospective design, these findings underscore the importance of effective infection-control measures and prudent antimicrobial use.
This study provides valuable local data on the microbial profile and antimicrobial susceptibility patterns of endotracheal aspirate isolates in intubated PICU patients. Continuous surveillance and institution-specific empirical antibiotic guidelines may improve clinical outcomes, reduce healthcare-associated infections, and optimize antimicrobial use in critically ill children.
Type of Study: Letter to the editor |
Subject:
Children's lungs
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