DIAGNOSTIC CYTOLOGY - BACTERIAL-INFECTIONS

Bacterial infections are a common cause of disease in small animals and can be diagnosed by using cytology. Detection of bacteria in cytologic smears requires a microscope with a x100 oil immersion lens as well as the ability of the practitioner to recognize cytologic features of various bacterial forms. Practitioners should also be able to distinguish these features from those of other similar objects often present in cytologic preparations. Bacteria can be recognized in cytologic smears because they comprise a population of objects that exhibit certain distinct features of form, size, and staining characteristics. Some fungi, protozoa, and other objects commonly encountered in cytologic preparations can mimic the appearance of bacteria. Guidelines for distinguishing bacteria from these objects are presented. Bacterial infections typically exhibit an inflammatory response that is;characterized by an increased number of neutrophils in smears. Guidelines for interpretation of cytologic smears that contain bacteria as infection versus contamination are provided. The diagnostic correlation between cytology and bacterial culture is discussed.