Table 2.

Prevalence of PPMs.

Author	PPMs (%)
Ewig et al., 2000 [22]	56
Soler et al., 1998 [24]	72
Nseir et al., 2006 [27]	30
Ferrer et al., 2005 [26]	69 *

Table 2 shows the prevalence of potentially pathogenic microorganisms (PPMs) categorized according to the respective studies. * Subgroup of mechanically ventilated patients.