Molecular characterization of the coagulase-negative staphylococcal surface flora of premature neonates

Abstract

A single point study was conducted to determine which surface sites best represent the density and composition of the coagulase-negative staphylococcal (CNS) colonizing flora in premature neonates. Five different surface sites of six randomly selected neonates hospitalized in a neonatal intensive care unit (NICU) for a month were examined. The individual strains and their clonal organization within CNS species were identified using restriction endonuclease fingerprinting of whole chromosomal DNA and ribosomal RNA genes. Cultures of the scalp, umbilicus, foot, nose and rectum were collected and quantitatively processed. Ten colonies were typed per surface culture. The most dense CNS colonization was noted on the umbilicus (mean 1.2 x lo4 c.f.u. em-*), foot (mean 1.6 x lo3 c.f.u. cm-') and nose (mean 1.7 x lo3 c.f.u. cm-') of NICU neonates. Scalp and rectum were scarcely colonized. Of all the CNS surface isolates, S. epidermidis accounted for 77.7% Colonization of each surface site comprised a maximum of five different strains representing four CNS species. Overall, five clones of S. epidermidis, two of S. haemofyticus, one of S. wavnevi and one of S. capitis were noted among the 282 isolates. The most predominant were two clones of S. epidermidis and one of S. haemofyticus; they accounted for 94% (265/282). Cultures from the foot and scalp represented the most heterogeneous CNS colonization of the five sites examined. Based on our findings of the existence of multiple strains of CNS at individual surface sites of NICU patients, we concluded that a minimum of five isolates be examined per surface culture to provide a comprehensive overview of the CNS colonizing flora.

Prevalence of antibiotic resistance in multi-drug resistant coagulase-negative staphylococci isolated from invasive infection in very low birth weight neonates in two Polish NICUs

“…The results obtained are similar to those of Bialkowska-Hobrzanska et al where 100% of isolates S. epidermidis and 92% of S. haemolyticus isolated from neonates were erythromycin-resistant [16], as well as similar to the data obtained by Abd El Hafez et al where the erythromycin resistance for isolates of S. epidermidis coming from neonates was 86% [6]. …”

“…The determined percentage of clindamycin resistance was significantly lower than that described by Bialkowska-Hobrzanska et al where for S. epidermidis it was equal to 92%, and for S. haemolyticus 85% [16]; similarly, Abd El Hafez et al demonstated 75.9% of isolates of S. epidermidis as resistant [6], and higher than that proven by van den Hoogen et al equal to 15% for CNS altogether [17]. …”

“…epidermidis , 100% for S. haemolyticus and it was higher than quoted in the literature for S. epidermidis 69.2 – 89.5% [17,21] and for CNS altogether 85% except the results obtained by Bialkowska-Hobrzanska et al where for both S. epidermidis and S . haemolyticus the resistance equaled 100% [16]. In the case of amikacin, the resistant strains of S .…”

Clinical Microbiology of Bacterial and Fungal Sepsis in Very-Low-Birth-Weight Infants

“…The major species involved in neonatal infection is S. epidermidis, which accounts for approximately 50 to 80% of CoNS colonization (52,185,407) and 60 to 93% of CoNS bloodstream infection (104). S. epidermidis colonization rates of 86 to 100% have been reported among NICU patients (104,138,187,228).…”

Bacterial Colonization of the Hospitalized Newborn: Competition Between Staphylococcus aureus and Staphylococcus epidermidis

“…Based on a literature search, [23][24][25][26][27][28][29][30] we anticipated a prevalence of nasal carriage at discharge of about 25% for S. aureus, 5% for MRSA, and 25% for S. epidermidis. The prevalence of nasal carriage of ESP-SE has not been explored in neonates.…”