What antibiotics are used to treat a Staphylococcus (Staph) urinary tract infection (UTI)?

Antibiotic Treatment for Staphylococcal Urinary Tract Infections

For Staphylococcus UTIs, first-line treatment options include trimethoprim-sulfamethoxazole (TMP-SMX), nitrofurantoin, or penicillinase-resistant penicillins (such as flucloxacillin or dicloxacillin), with the specific choice depending on susceptibility patterns. 1, 2

Antibiotic Selection Based on Staphylococcal Species

Methicillin-Susceptible Staphylococcus aureus (MSSA)

• Penicillinase-resistant penicillins (flucloxacillin, dicloxacillin) are the antibiotics of choice for serious MSSA infections 2
• First-generation cephalosporins (cefazolin, cephalothin, cephalexin) are effective alternatives for less serious infections 2
• Clindamycin is another option for patients with penicillin allergy (except in cases of immediate hypersensitivity) 2
• TMP-SMX (160/800 mg twice daily) is effective for uncomplicated UTIs caused by susceptible strains 1, 3

Methicillin-Resistant Staphylococcus aureus (MRSA)

• For serious MRSA infections, parenteral vancomycin is the treatment of choice 2
• For less serious community-acquired MRSA infections, lincosamides (clindamycin, lincomycin) or TMP-SMX are appropriate 2
• Linezolid has good anti-staphylococcal activity but should be reserved for patients who fail conventional therapy 2

Staphylococcus saprophyticus

• Common cause of UTIs, particularly in young women 4
• Amoxicillin-clavulanate is effective against S. saprophyticus 4
• Note that S. saprophyticus may have high MICs for ceftriaxone, making this a less optimal choice 4
• Nitrofurantoin is effective for uncomplicated lower UTIs caused by S. saprophyticus 5

Treatment Duration and Approach

Uncomplicated Lower UTI (Cystitis)

• 3-5 days of therapy is generally sufficient for uncomplicated cystitis 1
• For men with staphylococcal UTI, a longer course (7 days) is recommended 1

Complicated UTI or Pyelonephritis

• 7-14 days of therapy is recommended for complicated UTIs 1
• For pyelonephritis requiring hospitalization, initial intravenous therapy with appropriate agents should be considered 1
• Options include fluoroquinolones, aminoglycosides (with or without ampicillin), or extended-spectrum cephalosporins 1

Special Considerations

Biofilm Formation

• Staphylococcus species are known to form biofilms, which can increase antibiotic resistance 3
• Biofilm-producing S. aureus strains show higher resistance to nitrofurantoin, tetracycline, erythromycin, and ciprofloxacin 3
• TMP-SMX and doxycycline may be more effective against biofilm-producing strains 3

Recurrent UTIs

• For recurrent staphylococcal UTIs, obtain urine cultures to guide therapy 1
• Consider underlying structural or functional abnormalities of the urinary tract 1
• Evaluate for the presence of foreign bodies or incomplete voiding 1

Antibiotic Selection Algorithm

1. Obtain urine culture and sensitivity before starting treatment when possible 1
2. For empiric therapy of uncomplicated cystitis:
   • First-line: TMP-SMX or nitrofurantoin 1, 5
   • Alternative: First-generation cephalosporins or amoxicillin-clavulanate 5, 4
3. For suspected or confirmed MRSA UTI:
   • Oral options: TMP-SMX, linezolid, or doxycycline 1, 2
   • Parenteral options: Vancomycin or teicoplanin 2
4. For complicated UTI or pyelonephritis:
   • Parenteral therapy with vancomycin (for MRSA) or flucloxacillin/cefazolin (for MSSA) 1, 2
   • Consider combination therapy for severe infections 6

Common Pitfalls and Caveats

• Avoid fluoroquinolones as empiric therapy due to increasing resistance rates unless susceptibility is confirmed 5
• Do not use cephalosporins in patients with immediate penicillin hypersensitivity (urticaria, angioedema, bronchospasm, or anaphylaxis) 2
• Avoid using rifampicin or fusidic acid as single agents due to rapid development of resistance 2, 6
• Remember that S. saprophyticus UTIs are often undertreated with inappropriate empiric therapy 4
• Do not treat asymptomatic bacteriuria, even with Staphylococcus species 1