Is Methicillin-Sensitive Staphylococcus Aureus (MSSA) bacteruria a serious condition?

From the Guidelines

MSSA bacteriuria is a serious condition that requires prompt evaluation and treatment, particularly in symptomatic or high-risk populations. When MSSA is found in urine, treatment typically involves antibiotics such as cefazolin, which has been shown to be effective in treating MSSA bacteremia, with some studies suggesting similar efficacy or even a trend towards superiority over other antibiotics such as ASPs 1. The choice of antibiotic therapy for MSSA bacteriuria depends on several factors, including symptoms, patient characteristics, and whether the infection has spread beyond the urinary tract.

Key Considerations

• MSSA bacteriuria can lead to severe complications like pyelonephritis, prostatitis in men, or systemic infection if left untreated.
• Asymptomatic bacteriuria often doesn't require treatment except in pregnant women or patients undergoing urologic procedures.
• Patients should complete the full course of antibiotics even if symptoms improve and increase fluid intake to help flush bacteria from the urinary system.
• Cefazolin is a preferable choice for treating MSSA bacteremia due to its efficacy and safety profile compared to ASPs 1.

Treatment Options

• Cefazolin: 500mg four times daily for 7-14 days
• Other antibiotics such as trimethoprim-sulfamethoxazole, cephalexin, or dicloxacillin may also be considered, but cefazolin is generally preferred due to its efficacy and safety profile 1. It's worth noting that the management of MSSA infections should follow established guidelines, which recommend the use of beta-lactam antibiotics as the drug of choice in the absence of allergy 1.

From the FDA Drug Label

Urinary Tract Infections: Due to E. coli, P. mirabilis. Skin and Skin Structure Infections: Due to S. aureus (including beta-lactamase-producing strains), S. pyogenes, and other strains of streptococci. Biliary Tract Infections: Due to E. coli, various strains of streptococci, P. mirabilis, and S. aureus. Bone and Joint Infections: Due to S. aureus. Genital Infections: (i.e., prostatitis, epididymitis) due to E. coli, P. mirabilis. Septicemia: Due to S. pneumoniae, S. aureus (including beta-lactamase-producing strains), P. mirabilis, E. coli.

MSSA bacteruria is bad because it can lead to serious infections such as septicemia and other complications. The presence of MSSA in the urine indicates a potential infection that requires medical attention.

• MSSA is a type of bacteria that can cause various infections, including urinary tract infections.
• Bacteruria refers to the presence of bacteria in the urine, which can be a sign of an underlying infection.
• The FDA drug label for cefazolin 2 indicates that S. aureus (including beta-lactamase-producing strains) can cause serious infections, including septicemia.

From the Research

Overview of MSSA Bacteruria

• MSSA bacteruria is a condition where Methicillin-Sensitive Staphylococcus Aureus (MSSA) is present in the urine, which can be a sign of a more serious infection.
• According to 3, Staphylococcus aureus bacteremia, including MSSA, is a leading cause of death from bacteremia worldwide, with a case fatality rate of 15% to 30% and an estimated 300,000 deaths per year.

Clinical Significance of MSSA Bacteruria

• A study by 4 found that MSSA bacteriuria is associated with invasive S. aureus disease, with 8.4% of MSSA cases developing invasive disease within 12 months.
• The same study found that patients with MSSA bacteriuria who did not have symptoms of a urinary tract infection (UTI) were more likely to have worse outcomes, including invasive S. aureus disease or death.
• Another study by 5 found that hospital-acquired MSSA bacteriuria was associated with a higher mortality rate (28%) compared to community-acquired bacteriuria (8%).

Treatment and Management of MSSA Bacteruria

• According to 3, initial treatment for S. aureus bacteremia, including MSSA, typically includes antibiotics active against MRSA, such as vancomycin or daptomycin.
• Once antibiotic susceptibility results are available, antibiotics should be adjusted, with cefazolin or antistaphylococcal penicillins recommended for MSSA.
• A study by 6 found that optimal early antibiotic therapy, including prompt initiation and optimal antibiotic selection, was associated with improved clinical cure rates in patients with MSSA bloodstream infections.

Risk Factors and Outcomes

• Risk factors for MSSA bacteruria include intravascular devices, recent surgical procedures, injection drug use, diabetes, and previous S. aureus infection 3.
• A study by 4 found that patients with MSSA bacteriuria who had underlying medical conditions, such as diabetes or heart disease, were more likely to have worse outcomes.
• Another study by 5 found that patients with MSSA bacteriuria who had a higher Charlson Comorbidity Index were more likely to have a poor outcome, including death.