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Staphylococcus saprophyticus is a coagulase-negative species of Staphylococcus bacteria. S. saprophyticus is often implicated in urinary tract infections.^[1]

  History

Until the last decade^[when?], coagulase-negative staphylococci occurring in urine specimens were usually regarded as a contaminant. In the early 1970s, more than ten years after the original demonstration of Staphylococcus saprophyticus in urine specimens, this species became recognized as a frequent cause of urinary tract infections. The bacterium has a capacity for selective adherence to human urothelium. It causes direct hemagglutination. The adhesin for S. saprophyticus is a lactosamine structure. This staphylococcal species produces an extracellular enzyme complex that can inhibit growth of both gram-positive and gram-negative bacteria.

Strains of S. saprophyticus have been isolated from humans and animal gastrointestinal tracts, meat and cheese products, vegetables, and environmental sources. ^[2]

  Pathogenicity

S. saprophyticus is implicated in 10-20% of urinary tract infections (UTIs). In females between the ages of about 17-27 it is the second most common causative agent of acute UTIs, after Escherichia coli. The bacteria may also reside in the urinary tract and bladder of sexually active females. ^[3] It is referred to as "honeymooner's" UTI due to its association with intercourse.

S. saprophyticus is phosphatase-negative, urease- and lipase-positive. Two subspecies for saprophyticus exist: S. saprophyticus subsp. bovis and S. saprophyticus subsp. saprophyticus, the latter more commonly found in human UTIs. S. Saprophyticus subsp. saprophyticus is distinguished by its being nitrate reductase negative and pyrrolidonyl arylamidase negative while S. Saprophyticus subsp. bovis is nitrate reductase positive and pyrolidonyl arymamidase negative. ^[4]

  Symptoms of infection

Some of the symptoms of infection by this bacteria are burning sensation when passing urine, the urge to urinate more often than usual, a 'dripping effect' after urination, weak bladder, a bloated feeling with sharp razor pains in the lower abdomen around the bladder and ovary areas, and razor-like pains during sexual intercourse.

Patients with UTIs caused by S. saprophyticus usually present with symptomatic cystitis. Signs and symptoms of renal involvement are also often registered.^[5] The urine sediment of a patient with UTI caused by S. saprophyticus has a characteristic appearance under the microscope. Chemical screening methods for bacteriuria do not always succeed in diagnosing UTI caused by S. saprophyticus. Even when such an infection occurs above the neck of the bladder, low numbers of colony-forming units (less than 10(5) cfu/ml) of S. saprophyticus are comparatively often found in the bladder and voided urine.

  Antibiotic susceptibility

S. saprophyticus is resistant to the antibiotic novobiocin, a characteristic that is used in laboratory identification to distinguish it fromS. epidermidis, which is also coagulase-negative but novobiocin-sensitive.S. saprophyticus is usually susceptible to antibiotics commonly prescribed for patients with UTI, with the exception of nalidixic acid. Quinolones are commonly used in treatment of S. saprophyticus urinary tract infections.^{[citation needed]}

  References