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Abstract Ventilator-associated pneumonia is the most common and fatal health care associated infection in ICUs. It leads to many complications such as prolonged duration of mechanical ventilation and subsequently prolonged hospital stay, increased hospital costs, and increase morbidity and mortality rates. Moreover, it is a major driver of antibiotic use in ICU patients. Pseudomonas aeruginosa is one of the most common causative pathogens. P. aeruginosa VAP is associated with considerable morbidity, prolonged hospitalization, increased cost, and mortality. The mortality of P. aeruginosa VAP is further increased when initial empiric antibiotic therapy is inadequate or inappropriate, often because of multidrug resistance (MDR). Thus, early diagnosis and appropriate medical treatments are the best strategies for fig.hting against these infections. It can take >2 days to identify P. aeruginosa from clinical samples using traditional culture-biochemical methods. Therefore, it is desirable to develop a fast, sensitive, and accurate assay to detect this pathogen. Recently, MCDA was devised and validated as a possible replacement for PCR-based assays which is easy, fast, specific, and very sensitive. So, the aim of our study is to detect the prevalence of P. aeruginosa among VAP patients in ICUs of Tanta University Hospitals through both phenotypic methods and MCDA assay and to evaluate sensitivity and specificity of MCDA assay for rapid detection of P. aeruginosa in comparison with traditional methods. This work was carried out at the Microbiology and Immunology Department, Faculty of Medicine, Tanta University during the period from January 2021 to January 2023. This study comprised 60 mechanically ventilated patients who showed signs and symptoms of VAP admitted during the period of research to intensive care units in Tanta University Hospitals. Endotracheal aspirate and bronchoalveolar lavage fluid samples were taken from patients with clinically suspected VAP under complete aseptic precautions. All samples were subjected to colony count and bacteriological examination including isolation and identification of different Grampositive and negative bacteria using routine standard methods, antimicrobial susceptibility tests using the disc diffusion method according to the CLSI guidelines and then detection of P. aeruginosa by multiple cross displacement amplification assay. The current study showed that the incidence of VAP was 83.3% while the remaining patients have no VAP. There was a significant difference between VAP and non-VAP groups regarding age and gender. The mean age of VAP patients was 57.42±11.59 whereas the mean age of non-VAP patients was 33.9±11.95 with the majority of VAP infections in patients aged above 50 years of age (78%). It also shows that there was male predominance in VAP patients (62%) while there was female predominance in non-VAP patients (80%). The present study revealed that there was a significant difference between both studied groups regarding associated comorbidities and mean duration of mechanical ventilation, where polytrauma was the main associated comorbidity (36%) followed by diabetic ketoacidosis (20%) in VAP patients, diabetic ketoacidosis and ischemic heart disease (30% for each) were the main associated comorbidities in non-VAP patients. The mean duration of mechanical ventilation was 13.02±4.41 in VAP patients vs 5.2±1.03 in non-VAP patients. The current study showed that VAP is caused mainly by Gramnegative bacteria (80%). The three most common isolated pathogens were K. pneumoniae (30%), P. aeruginosa (25%), and S. aureus (20%). The current study showed the MDR rate in the present study was 83.3% with highest percentage in Acinetobacter baumannii and P. aeruginosa (100%) followed by K. pneumoniae (88.8%), then S. aureus (75%) and (71.4 %) in E-coli isolates. In the current study, all P. aeruginosa culture positive cases had positive result via MCDA test. Also, all cases that showed negative results in culture showed negative results via MCDA test. So, sensitivity and specificity of MCDA test were 100%. Thus, the accuracy of this test was 100% when compared with the results of culture. |