Infectious Diseases




Common Antibiotics in Neonates



Listen




| Download (.pdf) | Print





















































































Antibiotic


Organisms Covered


Dose


Notes


Ampicillin


Gram-positive organisms (Streptococcus spp.)


Susceptible Escherichia coli


Listeria monocytogenes


Empiric treatment for early- or late-onset (age >72 hrs) sepsis:



  • ≤7 d old: 150 mg/kg/dose IV q12h
  • >7 d old: 75 mg/kg/dose IV q6h

Treatment >48 h:



  • Meningitis or no CSF obtained: 75 mg/kg/dose IV q6h
  • Sepsis without meningitis: 75 mg/kg/dose IV q12h

Piperacillin


Pseudomonas aeruginosa Enterococcus spp.


Other Gram-negative enteric and anaerobes


PCN-susceptible Staphylococcus spp.


Streptococcus spp.



  • ≤7 d: 50 mg/kg/dose q8h
  • >7 d: 50 mg/kg/dose q6h

Moderate CSF penetration


Penicillin GK


GBS


Treponema pallidum


GBS meningitis:



  • ≤7 d postnatal age: 450,000 units/kg/d divided every 8 h
  • >7 d postnatal age: 450,000–500,000 units/kg/d divided every 4 h

Other GBS infections: 200,000 units/kg/d divided every 6 h


Nafcillin


Methicillin-sensitive Staphylococcus aureus


Non-CNS infections:



  • <30 wk postmenstrual age (PMA):

    • ≤7 d: 25 mg/kg/dose q12h
    • >7 d: 25 mg/kg/dose q8h

  • 30–37 wk PMA:

    • ≤7 d: 25 mg/kg/dose q12h
    • >7 d: 25 mg/kg/dose q8h

  • >37 wk PMA:

    • ≤7 d: 25 mg/kg/dose q12h
    • >7 d: 25 mg/kg/dose q6h

Meningitis:



  • Use 50 mg/kg/dose at same interval as listed above

Cleared primarily by the liver → monitor LFTs on treatment


Can cause interstitial nephritis → monitor renal function weekly on treatment


Can cause bone marrow suppression → monitor CBC weekly on therapy


Vancomycin


Aerobic and anaerobic Gram-positive cocci and bacilli


Methicillin-resistant S. aureus (MRSA)


Coagulase-negative staphylococci


Clostridium difficile


Bacillus spp.


Ampicillin-resistant Enterococcus



  • <30 wk PMA:

    • ≤7 d: 20 mg/kg/dose IV q24h
    • >7 d: 20 mg/kg/dose IV q18h

  • 30–37 wk PMA:

    • ≤7 d: 20 mg/kg/dose IV q18h
    • >7 d: 15 mg/kg/dose IV q12h

  • >37 wk PMA:

    • ≤7 d: 15 mg/kg/dose IV q12h
    • >7 d: 15 mg/kg/dose IV q8h

  • >44 wk PMA (meningitis):

    • 15 mg/kg/dose IV q6h

Only 10%–15% of serum concentration enters CSF.


Optimal serum concentration:



  • Trough: 15–20 mcg/mL

Gentamicin, amikacin, tobramycin


Broad Gram-negative bacillus coverage


Synergistic against S. aureus, GBS, L. monocytogenes, enterococci


Gentamicin



  • Indications: early- or late-onset sepsis (age >72 h); covers Gram-negative rods; use for synergy

    • <35 wk PMA: 3 mg/kg/dose IV q24h
    • ≥35wk PMA: 4 mg/kg/dose IV q24h

  • If given >48 h (>2 doses), draw gentamicin trough before and peak level after the third dose. Monitor BUN/Cr:

    • Optimum levels: peak= 5–10 mcg/mL, trough = <1.5 mcg/mL

  • For SYNERGY (against S. aureus, Enterococcus):

    • 1–1.5 mg/kg/dose IV q24h

Tobramycin



  • <30 wk PMA:

    • ≤7 d: 3 mg/kg/dose q24h
    • >7 d: 3 mg/kg/dose q18h

  • 30–37 wk PMA:

    • ≤7 d: 3 mg/kg/dose q18h
    • >7 d: 2.5 mg/kg/dose q12h

  • >37 wk PMA:

    • ≤7 d: 2.5 mg/kg/dose q12h
    • >7 d: 2.5 mg/kg/dose q8h

  • Optimum levels: peak = 8–10 mcg/mL; trough = <2 mcg/mL

Amikacin



  • <30 wk PMA:

    • ≤7 d: 15 mg/kg/dose q24h
    • >7 d: 15 mg/kg/dose q18h

  • 30–37 wk PMA:

    • ≤7 d: 15 mg/kg/dose q18h
    • >7 d: 15 mg/kg/dose q12h

CSF penetration depends on meningeal inflammation.


Monitor peak and trough levels, as these antibiotics can cause nephrotoxicity and ototoxicity.



  • >37 wk PMA:

    • ≤7 d: 15 mg/kg/dose q12h
    • >7 d: 15 mg/kg/dose q8h

  • Optimum levels: peak = 15–40 mcg/mL; trough = <10 mcg/mL

Clindamycin


Gram-positive cocci


Anaerobes (including Bacteroides fragilis)



  • ≤37 wk PMA:

    • ≤7 d: 5 mg/kg/dose q8h
    • >7 d: 10 mg/kg/dose q8h

  • >37 wk PMA:

    • 13 mg/kg/dose q8h

Poor CSF penetration


Cleared by the liver → monitor LFTs while on therapy


First-generation cephalosporins (cefazolin, cephalexin)


Susceptible Staphylococcus, Streptococcus, and pneumococci


Cefazolin:



  • ≤7 d postnatal age:

    • 20 mg/kg/dose q12h

  • >7 d postnatal age:

    • <2000 g: 20 mg/kg/dose q12h
    • >2000 g: 20 mg/kg/dose q8h

Poor CSF penetration


Second- generation cephalosporins (cefuroxime, cefoxitin, cefotetan, cefprozil)


Same as first generation


plus


Haemophilus influenzae


E. coli


Citrobacter


Klebsiella


Enterobacter cloacae


Improved activity over first-generation against β-lactamase–producing organisms


Little data in neonates, so use is limited


Third-generation cephalosporins (ceftriaxone, cefdinir, ceftazidime, cefotaxime, cefixime)


Gram-negative enterics


H. influenzae


Neisseria gonorrheae


Neisseria meningitidis


Cefotaxime:



  • <1200 g, 0–4 wk: 50 mg/kg/dose q12h
  • ≤7 d postnatal age:

    • 1200–2000 g: 50 mg/kg/dose q12h
    • >2000 g: 50 mg/kg/dose q8–12h

  • >7 d postnatal age:

    • 1200–2000 g: 50 mg/kg/dose q8h
    • >2000 g: 150–200 mg/kg/d divided q6–8h

Ceftazidime:



  • <7 d postnatal age:

    • 50 mg/kg/dose q12h

  • 1–4 wk postnatal age:

    • 30–50 mg/kg/dose q8h

Ceftazidime can be used for adequate coverage of Pseudomonas aeruginosa.


Ceftazidime, cefotaxime, and ceftriaxone all achieve good CSF penetration.


Ceftriaxone displaces bilirubin from albumin, raising serum levels of free unconjugated bilirubin → not recommended for use in neonates except in treating gonococcal infection in nonjaundiced neonates. In jaundiced neonates, use cefotaxime.


Ceftriaxone



  • ≤7 d postnatal age:

    • 50 mg/kg/d q24h

  • >7 d postnatal age:

    • ≤2000 g: 50 mg/kg/d q24h
    • >2000 g: 50–75 mg/kg/d q24h

  • Gonococcal prophylaxis:

    • 25–50 mg/kg as a single dose (maximum: 125 mg/dose)

  • Gonococcal infection:

    • 25–50 mg/kg/d (maximum: 125 mg/dose) q24h for 7 d, up to 10–14 d if meningitis is documented

Macrolides (azithromycin)


Gram-positive bacteria


MRSA


Neisseria spp.


T. pallidum


Chlamydia trachomatis


Bordetella pertussis


Infants <6 mo:



  • Pertussis (IV, oral): 10 mg/kg daily for 5 d

Oxazolidinone (linezolid)


Resistant Enterococcus faecium, S. aureus, Streptococcus pneumoniae


Neonates:



  • 10 mg/kg/dose q8h

Preterm infants:



  • 10 mg/kg/dose q12h

Use must be approved by infectious disease service


Carbapenems (meropenem)


Aerobic and anaerobic Gram-positive and Gram-negative bacteria


0–7 d postnatal age:



  • Non-meningitis: 20 mg/kg/dose q12h
  • Meningitis: 40 mg/kg/dose q12h

>7 d postnatal age:



  • Weight 1200–2000 g:

    • Non-meningitis: 20 mg/kg/dose q12h
    • Meningitis: 40 mg/kg/dose q12h

  • Weight >2000 g:

    • Non-meningitis: 20 mg/kg/dose q8h
    • Meningitis: 40 mg/kg/dose q8h

Use must be approved by infectious disease service


Good CSF penetration


Resistant organisms: Burkholderia cepacia, E. faecium, Stenotrophomonas maltophilia





Neonatal Meningitis



Listen




| Download (.pdf) | Print

Overview of Etiology and Treatment of Neonatal Meningitis























Age of Infant


Most Common Etiologies


Empiric Therapy


Length of Therapy


<1 mo


L. monocytogenes, GBS, Enterobacteriaceae (E. coli)


Ampicillin and cefotaxime OR ampicillin and gentamicin


If Gram-negative bacilli, use cefotaxime instead of gentamicin, as gentamicin has poor CSF penetration.


14–21 d: GBS, L. monocytogenes


21 d: Enterobacteriaceae (cefotaxime + aminoglycoside)


1–3 mo


GBS, S. pneumoniae, N. meningitidis, H. influenzae, Enterobacteriaceae


Ampicillin and cefotaxime


10–14 d: S. pneumoniae


7 d: N. meningitidis


7–10 d: H. influenzae


>3 mo


S. pneumoniae, N. meningitidis, H. influenzae, above neonatal pathogens


Cefotaxime or ceftriaxone


Add vancomycin if possible PCN-resistant S. pneumoniae until susceptibilities return


Same as above





Consider less common forms of neonatal meningitis if index of suspicion is high based on history or physical examination findings: viral (HSV (meningoencephalitis), enterovirus, VZV), tuberculosis, fungal, and noninfectious causes (eg, leukemic infiltrates).




Clinical Features




  • Neurologic: seizures, lethargy, irritability, decreased tone; full fontanelle
  • Fever (>38°C) or hypothermia (more common in preterms)
  • Respiratory distress: grunting, tachypnea, nasal flaring
  • Poor feeding
  • Diarrhea, vomiting
  • Apnea




Risk Factors




  • Premature rupture membranes, maternal fever/infection, fetal hypoxia, birth trauma, galactosemia (E. coli sepsis), low birth weight, preterm infants (<37 wk)




Workup




  • CBC, blood culture, UA with microscopy/culture, LP (cell count, protein, glucose, Gram stain/culture), PCR studies if indicated (HSV, enterovirus, VZV, LCMV)
  • Viral surveillance cultures, if indicated: conjunctiva, nasopharynx, rectum
  • Culture any cutaneous lesions concerning for HSV, VZV:

    • Classic finding of ↓ CSF glucose, ↑ CSF protein, and pleocytosis: seen more with early GBS meningitis, Gram-negative meningitis and late Gram-positive meningitis; may also be suggestive of viral meningitis (eg, enterovirus).
    • Only if all three parameters are normal does LP provide evidence against infection; no single CSF parameter can exclude the presence or absence of meningitis in neonates.
    • Bacterial meningitis commonly causes CSF pleocytosis >100 WBC/μL, predominantly polymophonuclear cells evolving to lymphocytes.
    • Viral meningitis in neonates: picture may be similar but with a less dramatic pleocytosis.
    • Maternal investigation: If possible, send placenta for pathology and, if indicated, cultures/PCR.
    • MRI/CT: to identify focal areas of infection, infarction, hemorrhage, edema, hydrocephalus, or abscess formation. Consider with focal neurologic abnormalities, persistent infection, or clinical deterioration.
    • Eye exam may be helpful to evaluate for chorioretinitis.




CSF Profiles for Infants with Birth Weight <1500 Grams



Listen




| Download (.pdf) | Print











































CSF Component


Weight (grams)


Postnatal Age (days)


0-7


8-28


29-84


Erythrocytes/mm3


≤1000


1001–1500


335 (0–1780)


407 (0–2450)


1465 (0–19,050)


1101 (0–9750)


808 (0–6850)


661 (0–3800)


Leukocytes/mm3


≤1000


1001–1500


3 (1–8)


4 (1–10)


4 (0–14)


7 (0–44)


4 (0–11)


8 (0–23)


Neutrophils (% of total leukocytes)


≤1000


1001–1500


11 (0–50)


4 (0–28)


8 (0–66)


10 (0–60)


2 (0–36)


11 (0–48)


Glucose (mg/dL)


≤1000


1001–1500


70 (41–89)


74 (50–96)


68 (33–217)


59 (39–109)


49 (29–90)


47 (37–76)


*Protein (mg/dL)


≤1000


1001–1500


162 (115–222)


136 (85–176)


159 (95–370)


137 (54–227)


137 (76–260)


122 (45–187)

Only gold members can continue reading. Log In or Register to continue

Jan 9, 2019 | Posted by in PEDIATRICS | Comments Off on Infectious Diseases
Premium Wordpress Themes by UFO Themes