Bacteriologic profile and susceptibility pattern of mechanically ventilated paediatric patients with pneumonia

•Ventilator-associated pneumonia was related to different pathogens according to the infection origin.•Community-acquired pneumonia was related to atypical bacteria, followed by Gram-positive bacteria.•Hospital- and PICU-acquired pneumonia were more related to Gram-negative bacteria (GNB).•Multidrug resistance is increasing, especially among hospital-acquired GNB.•Changing empirical therapy for MDR-GNB to agents such as colistin or tigecycline is recommended. Due to the current widespread bacterial resistance to many antibiotics − especially extended-spectrum β-lactams, carbapenems, and anti-pseudomonal drugs − therapy for severe pneumonia is very challenging. This study aimed to assess antimicrobial sensitivity patterns and optimisation of the antibiotic stewardship program applied at a university-affiliated paediatric intensive care unit (PICU). This prospective cohort study included all patients aged 1 month to 12 years, admitted to the PICU with severe pneumonia episodes indicated for mechanical ventilation, and were followed up and investigated. Non-bronchoscopic bronchoalveolar lavage specimens were tested for positive microbiological yields and examined for their susceptibility pattern. Of 85 patients with 96 episodes, 69 of them yielded positive growth: 43 were community-acquired pneumonia episodes, 62.79% of which were of unidentified cause. The isolated bacteria were predominantly due to Chlamydia pneumonia (18.6%) followed by Staphylococcus aureus and its resistant form (9.3%). Hospital and ventilator-associated pneumonia were mainly related to Gram-negative bacteria (91.67% and 87.8%, respectively), especially Klebsiella acinetobacter and Pseudomonas. There was a significant increase in multi-drug resistance among Gram-negative bacteria, which was considered an independent risk factor of mortality (P=0.003). Severe community-acquired pneumonia was treated with macrolides in combination with vancomycin or linezolid if methicillin-resistant S. aureus was suspected. This was appropriate, in view of its causative agents and their susceptibility pattern. Hospital and ventilator-associated pneumonia caused by resistant Gram-negative organisms might have better outcomes by adding tigecycline or colistin in combination with fluoroquinolones. Owing to the widespread resistance of many Gram-negative bacteria, it is recommended that the antibiotic stewardship program be frequently updated.