Fascinoma Rounds
Coagulase negative staphylococcus in the urine
October 26th, 2005
Sharmistha Mishra,
Vanessa Allen,
And with great thanks to Subash Mohan
Case 2: Coagulase negative
staphylococcus in the urine
• What is the clinical significance of finding CN
staph in urine?
Pathogens
• Coagulase negative staphylococcus
• 35 spp. ~ 15 potential human pathogens
– Staphylococcus saprophyticus
• Common cause of UTI in young women
• Treated as outpatients
– Staphylococcus epidermidis
• Rare growth in urine
• Generally hospital acquired
– Distiguished by novobiocin in the lab
Urinary Tract Infections Caused by
Coagulase-Negative Staphylococci:
Characteristics of Infections
Organism
S. epidermidis
S. saprophyticus
Age and sex of affected
patients
Men and women equal
Usually older than 50
years
Women 95% 16 to 35
years old
Population at risk
Hospitalized patients with
urinary tract complications
Healthy outpatients
Incidence
Uncommon: 3.5% or less
of all urinary tract
infections in hospitalized
patients
Common: 20% or more of
all urinary tract infections
in this age group
Presentation
90% asymptomatic
90% symptomatic
Therapy
Often resistant to multiple
antibiotics
Responds readily to
urinary tract
antimicrobials; except
nalidixic acid
Outcome
Bacteriuria often persists
after therapy
Relapse rare; occasional
reinfection
Septicemia Associated with Staph epidermidis
UTI - Case #1
• 77M with DM and HTN
• Right hip sub-trochanteric fracture and ORIF
• Subsequent urinary incontinence -> indwelling Foley catheter
• Two weeks later he had high grade fever, confusion, and
lethargy (foley had already been removed), temperature was
39.4° C , blood pressure 70/0 mm Hg, HR 126/min
• IV NS, ampicillin, and aztreonam and dopamine
• Two blood cultures = S epidermidis.
• Urine specimen = S epidermidis (> 106 colony-forming
units/mL)
• Same susceptibility pattern (vancomycin, tetracycline, and
trimethoprim-sulfamethoxazole).
Cadorna, EA. et al, SMJ, 0038-4348, Aug 1, 1995, vol. 88, issue 8
Septicemia Associated with Staph
epidermidis UTI - Case #2
• 64M in MVA , traumatic rupture of left hemidiaphragm
• Exploratory laparotomy with repair of diaphragm, left chest tube thoracostomy,
and feeding jejunostomy placement
• 3 weeks later, pulmonary embolism -> placement of an IVC filter
• @ 8 weeks, the jejunostomy tube, Foley catheter, intravenous lines, and
tracheostomy tube were removed.
• Three weeks later, his temperature rose to 39.4°C; blood pressure was 64/46
mm Hg, and the heart rate was 124/min.
• Two blood cultures = S epidermidis.
• Urine culture S epidermidis (>106 CFU/mL) with the same antimicrobial
susceptibility pattern (vancomycin, tetracycline, trimethoprimsulfamethoxazole).
Possible Explanations
• Hematogenous spread of staphylococcus
epidermidis
• Staphylococcus lugdunensis
– vs other CN staph species
S. lugdunensis
• CN staph
• Transient skin flora, inguinal area
• Identified by PYR hydrolysis and ornithine decarboxylate
activity
• More virulent than other CN staph
– lipase, esterase, glycocalyx and fibrinogen affinity factor
• Focus of infection (229)
–
–
–
–
–
–
–
–
skin and soft tissue infections (7, 65)
respiratory infections (13)
endocarditis
Bacteremia (15)
brain abscess
vascular prosthesis infection (11)
osteomyelitis.
Abscesses 14
Staphylococcus lugdunensis UTIs
• Generally reported as mixed flora in urine
• Rarely a contaminant
• Case #1
– 6F admitted with a 16 h history of fever to 39.7°C, flank
pain, nausea and vomiting.
– WBC 18.14
– A catheter specimen urinalysis showed proteinuria (1+),
traces of blood and absence of nitrites
– microscopic analysis showed 10–20 leukocytes with a
small number of bacteria.
– Urine culture showed growth of >100,000 colonies/ml of
S. lugdunensis in a pure culture.
Casanova-Roman M. et al. Scandinavian Journal of Infectious Diseases. 36(2):149-50, 2004.
Clinical correlate of staph lugdunensis
in urine culture
• Mayo Clinic
• 500 isolates of coagulase-negative
staphylococci from 4,652 consecutive
urine specimens
• 31/500 (6%) staph lugdunensis
• 29/31 of mixed flora
• 70% not treated
Haile Dt et al. Journal of Clinical Microbiology. 40(2):654-6, 2002 Feb.