Staphylococcal scalded skin syndrome in an extremely low-birth-weight neonate: molecular characterization and rapid detection by multiplex and real-time PCR of methicillin-resistant Staphylococcus aureus.
BACKGROUND
Staphylococcal scalded skin syndrome (SSSS), caused by methicillin-resistant Staphylococcus aureus (MRSA) producing exfoliative toxin (ET), is a life-threatening infection for neonates in neonatal intensive care units (NICUs). SSSS in extremely low-birth-weight (ELBW) neonates is rare. A new class of MRSA (community-acquired MRSA, CA-MRSA) has been emerging in the community. The aim of this study was to characterize MRSA from an ELBW neonate with SSSS, and to develop rapid detection methods for SSSS-associated and emerging pediatric MRSA.


METHODS
An ELBW infant in the NICU developed SSSS on day 16 after birth. Isolated MRSA was genetically characterized and compared with CA-MRSA from bullous impetigo (biCA-MRSA), which is positive for the ET and collagen-adhesin (CNA) genes in many cases, and the Panton-Valentine leucocidin (PVL) gene rarely. Specific primers and probes for five virulence genes (for ETA, ETB, ETD, PVL, CNA) were designed for multiplex polymerase chain reaction (PCR) and real-time PCR.


RESULTS
MRSA strain H5 from SSSS exhibited the genotype (ST91, spa416[t375], agr3, SCCmecIVa, CoaI), and possessed the ETB and CNA genes, similar to ST91 biCA-MRSA (albeit with a divergence). Multiplex PCR detected the ETB and CNA genes of strain H5, and real-time PCR detected strain H5 at as low as 10(2)  CFU/mL. The assays were 100% specific and 100% sensitive, for the five virulence genes.


CONCLUSIONS
ETB-positive ST91 MRSA, which was very similar to ST91 biCA-MRSA, was isolated from an ELBW infant with SSSS. The multiplex and real-time PCR assays specifically or quantitatively detected SSSS-associated and emerging pediatric MRSA.
Shi
Da
D
Division of Bacteriology, Department of Infectious Disease Control and International Medicine Department of Obstetrics and Gynecology, Niigata, Japan.
Ishii
Shiro
S
Sato
Takashi
T
Yamazaki
Hajime
H
Matsunaga
Masamichi
M
Higuchi
Wataru
W
Takano
Tomomi
T
Yabe
Shizuka
S
Tanaka
Kenichi
K
Yamamoto
Tatsuo
T
D000890:Anti-Infective Agents / Q000627:therapeutic use; D003982:Dibekacin / Q000031:analogs & derivatives / Q000627:therapeutic use; D006801:Humans; D007074:Immunoglobulin G / Q000627:therapeutic use; D007155:Immunologic Factors / Q000627:therapeutic use; D052577:Infant, Extremely Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000175:diagnosis* / Q000382:microbiology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000235:genetics; D016133:Polymerase Chain Reaction; D013206:Staphylococcal Scalded Skin Syndrome / Q000175:diagnosis* / Q000188:drug therapy / Q000382:microbiology*
D000890:Anti-Infective Agents; D007074:Immunoglobulin G; D007155:Immunologic Factors; D003982:Dibekacin; C031986:arbekacin