Uncomplicated Staph Aureus Bacteremia
- No evidence of endocarditis
- No prosthetic device
- No evidence of metastatic infection
- Defervescence after 72 hours of active antibiotic treatment
- Negative blood cultures at 48-96 hours
- Antibiotics for 14 days
Complicated Staph Aureus Bacteremia
- Prosthetic device (i.e. pacemaker, prosthetic joint, hemodialysis line)
- Evidence of metastatic infection (abscess, vertebral osteomyelitis, etc.)
- Persistent bacteremia, despite 3 or more days of antibiotic treatment
- Antibiotics for 4-6 weeks
Treatment options for Staph Aureus:
- Vancomycin, if intolerant: Daptomycin +/- Cloxacillin
- If MSSA, can use Cloxacillin
- If MRSA, use Vancomycin
Jr, V. G. (2003, September 22). Clinical Identifiers of Complicated Staphylococcus aureus Bacteremia. Retrieved from https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/216060
Controversy surrounds the use of antibiotics in the treatment of enterohemorrhagic Escherichia coli (EHEC) infections due to concerns about triggering hemolytic-uremic syndrome (HUS). The most common EHEC serotype causing human diseases worldwide is O157:H7.
Antibiotic therapy is generally NOT beneficial or recommended in patients with EHEC infection (particularly in children <10 years).
WHY? Several studies have shown increased induction of Shiga toxin with antibiotic therapy (i.e fluoroquinolones, trimethoprim-sulfamethoxazole, ampicillin). Shiga toxin is the major virulence factor of EHEC involved in the pathogenesis of HUS.
- Holtz LR, Neill MA, Tarr PI . 2009. Acute bloody diarrhea: a medical emergency for patients of all ages. Gastroenterology 136:1887–1898.
- Smith KE, et al . 2012. Antibiotic treatment of Escherichia coli O157 infection and the risk of hemolytic uremic syndrome, Minnesota. Pediatr. Infect. Dis. J. 31:37–41.
- Tarr PI, Gordon CA, Chandler WL . 2005. Shiga-toxin-producing Escherichia coli and haemolytic uraemic syndrome. Lancet 365:1073–1086.
- Wong CS, Jelacic S, Habeeb RL, Watkins SL, Tarr PI . 2000. The risk of the hemolytic-uremic syndrome after antibiotic treatment of Escherichia coli O157:H7 infections. N. Engl. J. Med. 342:1930–1936.
- Buchholz U, et al . 2011. German outbreak of Escherichia coli O104:H4 associated with sprouts. N. Engl. J. Med. 365:1763–1770.
- Bielaszewska, Martina et al. Effects of Antibiotics on Shiga Toxin 2 Production and Bacteriophage Induction by Epidemic Escherichia coli O104:H4 Strain. Antimicrob. Agents Chemother. June 2012 vol. 56 no. 6 3277-3282.
- Wong, C.S. et al. Risk factors for the hemolytic uremic syndrome in children infected with Escherichia coli O157:H7: a multivariable analysis. Clin Infect Dis. 2012;55(1):33.
The Jarisch-Herxheimer reaction is commonly seen in the first 24 hours of treatment and is characterized by low-grade fever, chills, headache, myalgias, malaise, and skin lesions (new or worsening of preexisting).
WHY? Thought to be due to cytokine release in response to endotoxins released by the dying microorganisms. May be seen following the treatment of spirochetal illnesses ( eg, Lyme disease, Syphilis, Leptospirosis).
*Typically treated with antipyretics.
- FARMER TW. JARISCH-HERXHEIMER REACTION IN EARLY SYPHILIS. JAMA. 1948;138(7):480-485. doi:10.1001/jama.1948.02900070012003
- Pound MW, May DB. Proposed mechanisms and preventative options of Jarisch-Herxheimer reactions. J Clin Pharm Ther 2005;30:291-295.
On an urine dipstick for suspected UTI, it is not uncommon to find positive nitrites. Nitrates are normally excreted by the kidney, however nitrites are not normally found in urine. Nitrites will be found when nitrate reductase organisms are present in the patient’s urine. These organisms are gram-negative bacteria including E. coli and other bacteria in the family Enterobacteriaceae (i.e Klebsiella).
NOTE: However, several other common urinary pathogens do not produce nitrites, such as: enterococci, S. saprophyticus, and Pseudomonas!! Therefore negative nitrites DOES NOT RULE OUT BACTERIURIA.
WATCH OUT FOR FALSE (-):
- If a patient has insufficient nitrates (i.e low vegetable intake in their diet), there may not be sufficient material to be converted by the bacteria
- It takes at least 4 hours for bacteria to convert nitrates to detectable levels of nitrite, so this test may be negative in patients with UTIs whose urinary frequency does not provide adequate time for bacterial conversion of nitrates to nitrites
- Simerville JA, Maxted WC, Pahira JJ. Urinalysis: a comprehensive review. Am Fam Physician. 2005 Mar 15;71(6):1153-62.
- Chapter 104. Urinalysis and Urine Electrolytes. Principles and Practice of Hospital Medicine. dam C. Schaffer, MD