Antibiotic Resistance in Neonatal Intensive Care Unit Pathogens: Mechanisms, Clinical Impact, and Prevention Including Antibiotic Stewardship
Section snippets
Epidemiology of AMR organisms in the NICU
The epidemiology of pathogens causing hospital-acquired infections in the NICU population is well described, although it should be noted that most of the literature has focused on late-onset sepsis. Gram-positive pathogens are more common causes of infections than gram-negative pathogens and yeast.2, 3 Staphylococcal species, most notably Staphylococcus epidermidis and Staphylococcus aureus, cause approximately 60% to 70% of infections. S epidermidis is the most common gram-positive pathogen,
Overview
An understanding of the mechanisms of resistance is predicated on an understanding of the mechanisms of action of antimicrobial agents. Briefly, antibacterial agents can bind to bacterial cell targets and prevent transcription (DNA to RNA) and translation (RNA to protein) or interfere with cell wall synthesis as described in Table 1. Antifungal agents have somewhat different mechanisms of action; amphotericin binds to ergosterol in fungal membranes causing leakage of fungal cell contents.20 The
Clinical impact of AMR pathogens
The mortality and morbidity of AROs may be related to increased virulence, delay in appropriate therapy, and fewer treatment options. Furthermore, antimicrobials required to treat AROs may be less effective, more expensive, or more toxic than conventional therapy. Resistance may be difficult to detect, can cause increased costs and length of stay, and may lead to a vicious cycle of antibiotic overuse, as broader empiric choices are then required. However, attributable mortality to AMR is
Judicious Use of Antibiotics
Infants hospitalized in the NICU have high rates of antibiotic use. In a national point-prevalence study of 29 NICUs in the United States, 43% of patients in the NICU were receiving antimicrobials on the survey date.67 Exposure to antibiotics is a risk factor for AROs; use of penicillin class agents have been associated with the emergence of MRSA,68 and in the NICU, use of third-generation cephalosporin agents have been associated with the emergence of ESBL GNB as well as invasive candidiasis.69
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