Staphylococcus saprophyticus: Characteristics and Diagnosis
Staphylococcus saprophyticus is one of the pathogenic species of staphylococci, the other two are S. aureus, and S. epidermidis. Staphylococcus epidermidis and S. saprophyticus are often referred to as coagulase-negative staphylococci (CONS).
Staphylococcus saprophyticus causes urinary tract infections (UTI), especially cystitis in sexually active young women. The organism is second to Escherichia coli as a cause of community-acquired urinary tract infections in young women.
- In Gram staining, Staphylococcus saprophyticus appears as Gram-positive cocci in clusters
- Coagulase production: No
- Typical hemolysis: None
- Resistant to novobiocin in contrast to S. epidermidis which is sensitive.
- Causes community-acquired UTI in young women.
Staphylococcus saprophyticus is a normal flora of the perineum, rectum, urethra, cervix, and gastrointestinal tract. It is found primarily on the mucosa of the genital tract in young women and from that site can ascend into the urinary bladder to cause urinary tract infections. Most women with this infection have had sexual intercourse within the previous 24 hours. Patients usually present with dysuria, pyuria, and hematuria.
Sample: Clean-catch mid-stream urine sample.
Find detailed information about the urine sample collection procedure here.
Urine culture: Though a positive urine culture is indicated by the presence of 100,000 colony-forming units per mL, S. saprophyticus is usually present in quantities less than or equal to 100,000 cfu/mL, but will be detected in sequential specimens.
If significant bacteriuria of gram-positive cocci is seen, the organism is identified by performing catalase and coagulase test. If the organism is catalase-positive and coagulase-negative, novobiocin test should be performed to differentiate S. epidermidis from S. saprophyticus. If the organism is sensitive to novobiocin, it is S. epidermidis, most likely to be the contaminant (normal flora). If the organism is novobiocin-resistant, it is identified as S. saprophyticus. It is a pathogen for the women of reproductive age group, so antimicrobial testing should be performed and the antibiogram result is reported to the physician.
Staphylococcus saprophyticus urinary tract infections can be treated with trimethoprim-sulfamethoxazole or a quinolone, such as ciprofloxacin.
Acharya TankeshwarHello, thank you for visiting my blog. I am Tankeshwar Acharya. Blogging is my passion. As an asst. professor, I am teaching microbiology and immunology to medical and nursing students at PAHS, Nepal. I have been working as a microbiologist at Patan hospital for more than 10 years.
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