''Staphylococcus saprophyticus'' is a

Gram-positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacte ...

coccus belonging to the genus '' Staphylococcus''. ''S. saprophyticus'' is a common cause of community-acquired

urinary tract infection A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidney ...

History

''Staphylococcus saprophyticus'' was not recognized as a cause of urinary tract infections until the early 1970s, more than 10 years after its original demonstration in urine specimens. Prior to this, the presence of

coagulase Coagulase is a protein enzyme 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. Importantly, '' S. aureus'' ...

-negative staphylococci (CoNS) in urine specimens was dismissed as contamination.

Epidemiology and pathogenesis

In humans, ''S. saprophyticus'' is found in the

normal flora The human microbiome is the aggregate of all microbiota that reside on or within human tissues and biofluids along with the corresponding anatomical sites in which they reside, including the skin, mammary glands, seminal fluid, uterus, ovarian ...

of the

female genital tract The female reproductive system is made up of the internal and external sex organs that function in the reproduction of new offspring. In humans, the female reproductive system is immature at birth and develops to maturity at puberty to be able ...

and

perineum The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...

. It has been isolated from other sources, too, including meat and cheese products, vegetables, the environment, and

human Humans (''Homo sapiens'') are the most abundant and widespread species of primate, characterized by bipedalism and exceptional cognitive skills due to a large and complex brain. This has enabled the development of advanced tools, culture, ...

and

animal Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...

gastrointestinal tracts. ''S. saprophyticus'' causes 10–20% of

s (UTIs). In females 17–27 years old, it is the second-most common cause of community-acquired UTIs, after ''

Escherichia coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

''. Sexual activity increases the risk of ''S. saprophyticus'' UTIs because bacteria are displaced from the normal flora of the vagina and perineum into the

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

. Most cases occur within 24 hours of sex, earning this infection the nickname "honeymoon cystitis". ''S. saprophyticus'' has the capacity to selectively adhere to human urothelium. The adhesin for ''S. saprophyticus'' is a lactosamine structure. ''S. saprophyticus'' produces no exotoxins.

Clinical features

Patients with urinary tract infections caused by ''S. saprophyticus'' usually present with symptomatic

cystitis A urinary tract infection (UTI) is an infection that affects part of the urinary tract. When it affects the lower urinary tract it is known as a bladder infection (cystitis) and when it affects the upper urinary tract it is known as a kidney ...

. Symptoms include a 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. Flank pain may occur due to infection of the upper urinary tract, such as pyelonephritis. Signs and symptoms of renal involvement are also often registered.

Laboratory diagnosis

The urine sediment of a patient with a ''S. saprophyticus'' urinary tract infection has a characteristic appearance under the microscope manifesting leukocytes, erythrocytes, and clumping due to cocci adhering to cellular elements. Chemical screening methods for bacteriuria, such as, urine nitrate and glucose do not always detect ''S. saprophyticus'' infection. This is because unlike

Gram-negative Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...

Enterobacteriaceae urinary tract infections, ''S. saprophyticus'' does not reduce nitrate and has a longer generation time, thus does not consume glucose as rapidly. Even when such an infection occurs above the neck of the bladder, low numbers of colony-forming units (less than 10⁵ cfu/ml) are often present. ''Staphylococcus saprophyticus'' is identified as belonging to the genus ''Staphylococcus'' using the

Gram stain In microbiology and bacteriology, Gram stain (Gram staining or Gram's method), is a method of staining used to classify bacterial species into two large groups: gram-positive bacteria and gram-negative bacteria. The name comes from the Danish ...

and

catalase test Catalase is a common enzyme found in nearly all living organisms exposed to oxygen (such as bacteria, plants, and animals) which catalyzes the decomposition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting t ...

. It is identitified as a species of coagulase-negative staphylococci (CoNS) using the

coagulase test Coagulase is a protein enzyme 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. Importantly, '' S. aureus'' ...

. Lastly, ''S. saprophyticus'' is differentiated from ''

S. epidermidis ''Staphylococcus epidermidis'' is a Gram-positive bacterium, and one of over 40 species belonging to the genus ''Staphylococcus''. It is part of the normal human microbiota, typically the skin microbiota, and less commonly the mucosal microbiot ...

'', another species of pathogenic CoNS, by testing for susceptibility to the antibiotic novobiocin. ''S. saprophyticus'' is novobiocin-resistant, whereas ''S. epidermidis'' is novobiocin-sensitive.

Treatment

''Staphylococcus saprophyticus'' urinary tract infections are usually treated with

trimethoprim-sulfamethoxazole Trimethoprim/sulfamethoxazole, sold under the brand name Bactrim among others, is a fixed-dose combination antibiotic medication used to treat a variety of bacterial infections. It consists of one part trimethoprim to five parts sulfamethoxaz ...

or with a quinolone such as to be alone

norfloxacin Norfloxacin, sold under the brand name Noroxin among others, is an antibiotic that belongs to the class of fluoroquinolone antibiotics. It is used to treat urinary tract infections, gynecological infections, inflammation of the prostate gland, g ...

. It has also been shown to be susceptible to ampicillin & ceftriaxone. The many home remedies or natural treatments for urinary tract infections are not clinically proven, such as cranberry juice, alkalinization, and many types of common herbs and spices. Some show promise, such as to affect the formation of

biofilm A biofilm comprises any syntrophic consortium of microorganisms in which cells stick to each other and often also to a surface. These adherent cells become embedded within a slimy extracellular matrix that is composed of extracellular ...

s on surfaces or medical equipment, and in other ''

in vitro ''In vitro'' (meaning in glass, or ''in the glass'') studies are performed with microorganisms, cells, or biological molecules outside their normal biological context. Colloquially called "test-tube experiments", these studies in biology an ...

'' situations.

Different subspecies

Two subspecies of ''S. saprophyticus exist'': ''S. s. bovis'' and ''S. s. saprophyticus'', the latter has colony diameter of > 5mm, and more commonly found in human UTIs. ''S. s. saprophyticus'' is nitrate-reductase negative and pyrrolidonyl-arylamidase negative, while ''S. saprophyticus bovis'' has colony diameter of < 5mm, nitrate-reductase positive and pyrolidonyl-arylamidase positive.

References

External links

Type strain of ''Staphylococcus saprophyticus'' at Bac''Dive'' - the Bacterial Diversity Metadatabase
{{Taxonbar, from=Q1708986 saprophyticus Gram-positive bacteria Bacteria described in 1940