Neonatal sepsis is a life-threatening emergency and any delay in treatment may cause death. Initial signs of
neonatal sepsis are slight and nonspecific. Therefore, in suspected
sepsis, two or three days empirical
antibiotic therapy should begin immediately after cultures have been obtained without awaiting the results.
Antibiotics should be reevaluated when the results of the cultures and susceptibility tests are available. If the cultures are negative and the clinical findings are well,
antibiotics should be stopped. Because of the nonspecific nature of
neonatal sepsis, especially in small preterm infants, physicians continue
antibiotics once started. If a baby has
pneumonia or what appears to be
sepsis,
antibiotics should not be stopped, although cultures are negative. The
duration of therapy depends on the initial response to the appropriate
antibiotics but should be 10 to 14 days in most infants with
sepsis and minimal or absent
focal infection. In infants who developed
sepsis during the first week of life, empirical
therapy must cover group B streptococci, Enterobacteriaceae (especially E. coli) and Listeria monocytogenes.
Penicillin or
ampicillin plus an
aminoglycoside is usually effective against all these organisms. Initial empirical
antibiotic therapy for infants who developed
sepsis beyond the first days of life must cover the organisms associated with early-onset
sepsis as well as hospital-acquired pathogens such as staphylococci, enterococci and Pseudomonas aeruginosa.
Penicillin or
ampicillin and an
aminoglycoside combination may also be used in the initial
therapy of late-onset
sepsis as in cases with early-onset
sepsis. In
nosocomial infections,
netilmicin or
amikacin should be preferred. In cases showing increased risk of
staphylococcal infection (e.g. presence of
vascular catheter) or
Pseudomonas infection (e.g. presence of typical skin lesions), antistaphylococcal or anti-Pseudomonas agents may be preferred in the initial empirical
therapy. In some centers,
third-generation cephalosporins in combinations with
penicillin or
ampicillin have been used in the initial
therapy of early-onset and late-onset
neonatal sepsis.
Third-generation cephalosporin may also be combined with an
aminoglycoside in places where
aminoglycoside-resistance to this
antibiotic is high. However,
third-generation cephalosporins should not be used in the initial
therapy of suspected
sepsis, because 1) extensive use of
cephalosporins for initial
therapy of
neonatal sepsis may lead to the emergence of
drug-resistant microorganisms (this has occurred more rapidly as compared with the
aminoglycosides), 2) Antagonistic interactions have been demonstrated when the other
beta-lactam antibiotics (e.g.
penicillins) were combined with
cephalosporins.
Infections due to gram-negative bacilli can be treated with the combination of a
penicillin-derivative (
ampicillin or extended-spectrum
penicillins) and an
aminoglycoside.
Third-generation cephalosporins in combination with an
aminoglycoside or an extended-spectrum
penicillin have been used in the treatment of
sepsis due to these organisms.
Piperacillin and
azlocillin are the most active of extended-spectrum
penicillins against Pseudomonas aeruginosa. Among the
third-generation cephalosporins,
cefoperazone and
ceftazidime possess anti-Pseudomonas activity.
Ceftazidime was found to be more active in vitro against Pseudomonas than
cefoperazone or
piperacillin. New
antibiotics for gram-negative bacteria resistant to other agents are
carbapenems,
aztreonam,
quinolones and
isepamicin. Enterococci can be treated with a cell wall-active agent (e.g.
penicillin,
ampicillin, or
vancomycin) and an
aminoglycoside. Staphylococci are susceptible to
penicillinase-resistant
penicillins (e.g.
oxacillin,
nafcillin and
methicillin). Resistant strains are uniformly sensitive to
vancomycin. A
penicillin or
vancomycin and an
aminoglycoside combination result in a more rapid bacteriocidal effect than is produced by either dr