NICU: Infectious Disease

Wash hands before touching every infant, every time.

The Sepsis Workup
Neonates with Suspected Sepsis
Suspected Sepsis in older NICU patients
Suspected Fungal infection

Sepsis

A full sepsis workup consists of a CBC with differential, blood culture, urine culture and urinalysis (optional within first 24 hours of life) and CSF studies including cell count and differential, protein, glucose, gram stain, bactogens (when appropriate), and culture. In a partial sepsis workup, the lumbar puncture (LP) is omitted. Prematurity is often a complication of maternal infection. Rupture of membranes more than 18 hours prior to delivery and maternal fever are, therefore, considered to be risk factors for neonatal sepsis (both term and preterm).

Management of Neonates with Suspected Sepsis

First ensure respiratory and hemodynamic instability. This may entail intubation, volume resuscitation, or vasoactive medications.

Obtain blood for CBC with differential and culture (also type and screen in certain cases). Blood may be obtained at the time of a UAC placement.

If urine culture is desired, obtain a specimen by suprapubic tap (preferable) or by sterile catheterization.

If infant is clinically stable enough, perform LP using a 22 gauge, 1.5 inch spinal needle. Be sure to replace the stylet before withdrawing the needle.

Send CSF tubes as follow, about 1 cc per tube
#1: gram stain, culture, sensitivity, bacterial antigens
#2: protein and glucose
#3: cell count and differential.
If maternal RPR is positive, send 1 cc for CSF VDRL. This volume can be added to tube #1.

Usual antibiotic therapy is ampicillin and gentamicin. Cefotaxime is sometimes used instead of gentamicin if renal function is impaired. Ampicillin covers Group B Strep., some enterococci, and Listeria (a rare pathogen). Gentamicin or cefotaxime covers gram negatives like E. coli as well as some penicillin-resistant pathogens. The dosage is based on gestational age and weight, consult a reference manual.

Management of suspected sepsis in the older NICU patient

Almost any decline in clinical status in a NICU patient can be early signs of sepsis.

Depending on the index of suspicion, a partial or full sepsis workup may be performed. At a minimum, a blood culture and CBC with differential should be obtained prior to antibiotic therapy.

Since nosocomial infections have a much higher rate of antibiotic resistance, choice of agent is different in this population. Cefotaxime (covering gram negatives) and vancomycin (covering Staph spp. and many penicillin-resistant organisms) can be used. However, careful consideration should be given prior to the use of vancomycin. We are seeing increasing incidence of vancomycin-resistant organisms (mainly Enterococcus and some pneumococci). Hospital policy determines when vancomycin is stopped; in some cases, it is 72 hours after negative cultures or when the organism is found to be sensitive to other antibiotics.

Management of Suspected Fungal Infections

Infants who are critically ill and have received multiple courses of broad-spectrum antibiotic therapy are at risk of developing systemic fungal infections, usually with Candida spp.

Workup for fungal infection is similar to a sepsis workup except that you must specify that blood and urine samples be held for fungal cultures. Fungal blood cultures may be sent in a glass green-top tube or a standard blood culture bottle (in the latter case, be extra careful to specifity that it is a fungal culture to prevent mishandling). If a blood culture for fungus is positive, the following tests are indicated:

Antifungal therapy should be instituted if strong clinical suspicion of fungal disease is present or positive cultures are obtained. Common agents for treatment are Fluconazole and Amphotericin B.

C. krusei

C. glabrata