Etiology of early and late ventilator-associated pneumonia
The multidrug-resistant Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA) are the most common pathogens of early and late ventilator-associated pneumonia.
In intubated patients undergoing mechanical ventilation (mechanical ventilation), a distinction is made between early (developing within 5 days after intubation) and late (more than 5 days after intubation) pneumonia. Early ventilator-associated pneumonia (VAP) is thought to be caused by staphylococci, pneumococci, Haemophilus spp. and representatives of the Enterobacteriaceae family who are sensitive to commonly used antibiotics; therefore, it is recommended to use narrow spectrum antibiotics such as aminopenicillins or cephalosporins without antiseptic activity. At the end of pneumonia, there is a high risk of polyresistance of pathogens, so it is recommended to treat with broad spectrum antibiotics with antiseptic activity, active against Staphylococcus aureus methicillin (MRSA), selected taking into account the local resistance situation.
A study in Greece involved 408 patients with respiratory pneumonia. All patients underwent mechanical ventilation for more than 48 hours, and there was clinical evidence to suspect a VAP. The diagnosis was confirmed by the detection of fresh pulmonary infiltration and two or more of the following criteria: purulent discharge from the respiratory tract, body temperature above 38.3 ° C, leukocytosis greater than 10,000 / mm3 or leukopenia less than 5,000 / mm3, the causative agent in the liquid obtained with a bronchoalveolar lavage, at a concentration greater than 104 CFU / ml. Pseudomonas aeruginosa (MDR PA) and multidrug-resistant MRSA were the most common pathogens for early (79%) and late (85%) VAPs. There was no difference in the etiological role of MDR PA (42% vs 47%) and MRSA (33% vs 30%) with early VAP and late. When these pathogens were isolated, mortality was significantly higher (18% vs 4%). In general, no difference in mortality in early and late VAPs was noted. Empirical therapy was changed in 58% of cases with early VAP and 36% of cases with late VAP. Almost all cases of inadequate and insufficient empirical treatment have been observed in patients with VAP caused by multidrug-resistant strains of Pseudomonas aeruginosa and MRSA.
Thus, it has been shown that the classification of pneumonia associated with ventilator at the beginning and end has almost no meaning. The patient's age and previous hospital stay with antibiotics are the two main factors indicating the risk of multiple resistance. Since there is an increase in the mortality rate due to insufficient empirical treatment with VAP caused by multidrug-resistant strains of Pseudomonas aeruginosa and MRSA, spectrum antibiotics Close action should no longer be used to treat early pneumonia associated with a ventilator. Empirical antimicrobial therapy should take into account the resistance profile in the intensive care unit and should include a drug with anti-Pseudomonas activity and glycopeptide in departments with a high prevalence of MRSA.