Nevertheless, conventional diagnostic methods
are often insufficient for etiological diagnosis, and
in half of these cases the causative pathogen cannot
be determined.3-7 The use of multiplex polymerase
chain reaction (PCR), which is reported to be a reliable
molecular method for diagnosing lower respiratory
tract infections, has been used increasingly in
recent years. The prominent advantage of PCR
method compared to culture is that, since PCR is
based on replicating the DNA or RNA of very small
amount of microorganisms, it does not require
living organisms and therefore is not affected by
the prior use of antibiotics. In addition, PCR is more
sensitive for detection of multiple microorganisms
and delivers fast results.