saprophyticus

Staphylococcus saprophyticus is a species of Gram-positive, nonmotile cocci that occur in grape-like clusters and belong to the genus Staphylococcus. It is coagulase-negative and catalase-positive. Historically linked to saprophytic life, it is also a member of the normal flora of the human skin and genitourinary tract, where it can be found without causing disease.

A distinguishing feature of S. saprophyticus is its resistance to novobiocin, which helps separate it from the closely related Staphylococcus epidermidis in laboratory testing. It is less pathogenic than Staphylococcus aureus but is a well-established cause of urinary tract infections.

Clinical significance centers on acute uncomplicated urinary tract infections, particularly in sexually active young women. It can cause cystitis and dysuria and may be found incidentally in asymptomatic bacteriuria. In rare cases, it can be implicated in bacteremia or endocarditis, especially in susceptible hosts.

Pathogenesis involves adhesion to uroepithelial cells and biofilm formation, enabling colonization of the urinary tract. Urease production and other surface factors may facilitate persistence in the urinary tract, particularly in catheter-associated contexts. Colonization of the vaginal and periurethral areas contributes to infection risk.

Laboratory diagnosis relies on routine bacterial culture and species identification. Characteristics include Gram-positive cocci in clusters, catalase-positive, coagulase-negative, and novobiocin-resistant. Additional tests may assess urease activity and mannitol fermentation to aid differentiation from other coagulase-negative staphylococci.

Treatment of uncomplicated UTIs caused by S. saprophyticus commonly involves nitrofurantoin or trimethoprim-sulfamethoxazole, guided by local susceptibility data. Antibiotic choices should be based on culture results and resistance patterns, with longer courses reserved for complicated infections.