A 62-year-old man comes to the hospital emergency department with a fever of 38.3″C and chills. He is tachycardic and tachypneic. Blood tests: leukocytosis with left shift. Blood pressure is 90/60 mmHg. No murmurs are heard on cardiac auscultation and chest X-ray rules out pneumonia. As history of interest she refers repeated urinary tract infections. A week ago the primary care physician prescribed cefuroxime, a drug he is currently taking. Two blood cultures were taken and urine was sent for sediment examination and microbiological culture. The sediment was pathological, with intense pyuria, but negative nitrites. After 24 hours, the microbiology laboratory reported that both the urine and the blood cultures were positive, and the results showed gram-positive cocci grouped in chains, pending identification and antibiogram. Pending the definitive result, what would you recommend?
With the urine nitrite test we detect the presence of nitrites in the urine. These appear due to the presence in the urine of a high concentration of bacteria possessing the enzyme nitrate reductase, which is capable of reducing the nitrates present in the urine to nitrites. This enzyme is active in most of the bacteria that most frequently cause urinary tract infection, such as many Gram-negative bacilli. Other microorganisms, relatively frequent causes of urinary tract infection, do not possess this enzyme and do not reduce nitrates, such as enterococci, staphylococci and yeasts. As the Gram stain indicates that the bacteria are grouped in chains, as this is typical of enterococcus, we suggest the need to cover this group of bacteria with antibiotic treatment. Staphylococci are typically seen on Gram stain as Gram-positive cocci forming clusters and yeasts, although with the same staining, have a different typical morphology than Gram-positive cocci.
Continue with cefuroxime while awaiting the definitive result, since the patient has undergone multiple treatments and we should not make a mistake in his current treatment.
Change to ertapenem, considering the possibility of multiresistant microorganisms.
Switch to a broad-spectrum antimicrobial treatment that covers Enterococcus spp.
Switch to broad-spectrum antimicrobial therapy containing imipenem, considering the possibility of Staphylococcus aureus, since our hospital has a high incidence of methicillin-resistant S. aureus (MRSA).
As the Gram stain indicates that the bacteria are grouped in chains, as this is typical of enterococcus, we suggest the need to cover this group of bacteria with antibiotic treatment.
Staphylococci are typically seen on Gram stain as Gram-positive cocci forming clusters and yeasts, although with the same staining, have a different typical morphology than Gram-positive cocci.