Clinical Laboratory Science Bacteriology Practice Test 2026 – Complete Exam Prep

Serratia species have a characteristic set of extracellular enzymes they commonly produce to break down different nutrients, including DNase, gelatinase, and lipase. DNase activity can be detected by clearing in a DNase test, signaling the organism can hydrolyze DNA. Gelatinase activity shows up as liquefaction of gelatin in a gelatin medium, reflecting gelatin breakdown. Lipase activity is demonstrated on lipid-containing substrates, indicating fat hydrolysis. NADase, a nicotinamide adenine dinucleotide hydrolase, is not a typical enzyme produced by Serratia and isn’t used to identify or characterize this genus. Therefore, NADase is the enzyme activity not produced by Serratia species.