To carry through an adequate antibioticoterapia it must be considered some factors: beyond a simple antibiotic combination with the bacteria, she is necessary to manage the certain medicine in the certain dose, preventing the occurrence of multiresistant patgenos, that is related to the two important factors – the previous antibiotic use and the duration of the VM. It is important to use possible fastest the adequate therapy empirical, and is necessary the knowledge of which patgenos are gifts in the UTI of each hospital, as well as its sensitivity, preventing themselves the extreme antibiotic use. (DAVID, 2000). The PAVM that occur until the room day of hospital internment, said of ' ' installation precoce' ' , they costumam to better have prognostic of what of ' ' installation tardia' ' (from five days), where the etiolgicos agents are comumente multidrogas-resistant bacteria (MDR), imposing the treatment necessity antimicrobials of wide specter (capable to act in a great number of bacteria, gram-positive and gram-negative). However, according to Patel (2002) apud Carrilho et al. (2006), the delayed PAVM are more common, being associates to the biggest risk of mortality and morbidade.
(TEIXEIRA, 2004). For its treatment, the antibiotic project must be aggressive, due to gravity of the case, becoming use of an antibiotic association, mainly in cases of VM drawn out, where the main .causing agents of this infection are: Staphylococcus aureus, aeruginosa Pseudomonas, and Enterobacteriaceae. These if in accordance with differentiate the patients in a UTI, duration of permanence in same and a precocious antimicrobial therapy. The costs with this treatment costumam to be raised, estimates indicate that in U.S.A. more than 300,000 nosocomiais respiratory infections occur to each year and approach expenses of US$ 30 billion in hospital cares and antibioticoterapia with these patients. (TOLEDO, 2009). According to Chastre, Fagon (2002) apud Carrilho (2006), due to high mortality of the PAVM, its diagnosis and treatment must be precocious, what it reduces the severity of the illness and improves its prognostic.