**3.5 Identification of infectious agents**

### **3.5.1 Conventional microbiological detection**

Direct gram staining of periprosthetic samples is insensitive and therefore not recommended as a routine test (Banit et al., 2002; Parvizi et al., 2006; Spangehl et al., 1999). However, it can be useful in certain cases of early infection, where prompt treatment of agents which show characteristic morphology (e. g. *Clostridium perfringens*) is enabled. Classic microbiologic culture confirms the presence of viable bacteria and permits testing for
