Staphylococcus saprophyticus
Staphylococcus saprophyticus is a coagulase
Coagulase is a protein produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Coagulase negativity excludes S. aureus. That is to say, S...

-negative species of Staphylococcus
Staphylococcus is a genus of Gram-positive bacteria. Under the microscope they appear round , and form in grape-like clusters....

bacteria. S. saprophyticus is often implicated in urinary tract infection
Urinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...

s. S. saprophyticus is resistant to the antibiotic novobiocin
Novobiocin, also known as albamycin or cathomycin, is an aminocoumarin antibiotic that is produced by the actinomycete Streptomyces niveus, which has recently been identified as a subjective synonym for S. spheroides a member of the order Actinobacteria . Other aminocoumarin antibiotics include...

, a characteristic that is used in laboratory identification to distinguish it from S. epidermidis
Staphylococcus epidermidis
Staphylococcus epidermidis is one of thirty-three known species belonging to the genus Staphylococcus. It is part of human skin flora, and consequently part of human flora. It can also be found in the mucous membranes and in animals. Due to contamination, it is probably the most common species...

, which is also coagulase-negative but novobiocin-sensitive.

It is implicated in 10-20% of urinary tract infection
Urinary tract infection
A urinary tract infection is a bacterial infection that affects any part of the urinary tract. Symptoms include frequent feeling and/or need to urinate, pain during urination, and cloudy urine. The main causal agent is Escherichia coli...

s (UTI). In females between the ages of ca. 17-27 it is the second-most-common cause of UTIs. It is referred to as "honeymooner's" UTI due to its association with intercourse. It may also reside in the urinary tract and bladder of sexually active females. S. saprophyticus is phosphatase
A phosphatase is an enzyme that removes a phosphate group from its substrate by hydrolysing phosphoric acid monoesters into a phosphate ion and a molecule with a free hydroxyl group . This action is directly opposite to that of phosphorylases and kinases, which attach phosphate groups to their...

-negative, urease
Urease is an enzyme that catalyzes the hydrolysis of urea into carbon dioxide and ammonia. The reaction occurs as follows:In 1926, James Sumner showed that urease is a protein. Urease is found in bacteria, yeast, and several higher plants. The structure of urease was first solved by P.A...

- and lipase
A lipase is an enzyme that catalyzes the formation or cleavage of fats . Lipases are a subclass of the esterases.Lipases perform essential roles in the digestion, transport and processing of dietary lipids in most, if not all, living organisms...

-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 negative and pyrrolidonyl arylamidase negative while S. Saprophyticus subsp. bovis is nitrate negative and pyrolidonyl arymamidase negative.

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


Until the last decade, 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 (UTI). In young women, S. saprophyticus is, after Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...

, the most frequent causative agent of acute UTI. Patients with UTI caused by S. saprophyticus usually present with symptomatic cystitis. Signs and symptoms of renal involvement are also often registered. 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. S. saprophyticus is usually susceptible to antibiotics commonly prescribed for patients with UTI, with the exception of nalidixic acid
Nalidixic acid
Nalidixic acid is the first of the synthetic quinolone antibiotics...

. 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.
Quinolones are commonly used in treatment of S. saprophyticus urinary tract infections.
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