DEVELOPMENT OF A NOVEL MULTIPLEX PCR METHOD FOR DETECTING THE MAJOR CLONAL COMPLEXES OF HEALTHCARE- AND COMMUNITY-ASSOCIATED METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA)
Open Access
Author:
Schwalm III, Nathan Daniel
Area of Honors:
Food Science
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
Stephen John Knabel, Thesis Supervisor Stephen John Knabel, Thesis Supervisor Edward G Dudley, Faculty Reader Stephen John Knabel, Thesis Honors Advisor
Keywords:
MRSA PCR microbiology
Abstract:
Methicillin-resistant Staphylococcus aureus (MRSA) is an increasingly common cause of
healthcare- and community-associated infections. MRSA is capable of causing many different
types of infections due to the large number of virulence factors it produces. The recent
emergence of healthcare-associated MRSA (HA-MRSA) strains with resistance to the best
available antibiotic treatments and community-associated (CA-MRSA) strains capable of highly
virulent infections has made the detection and characterization of these strains even more
important. Several molecular methods have been used for either the detection of MRSA strains
or the characterization and identification of MRSA clones. However, a need exists for a method
that provides a link between the detection and clonal characterization of isolates. To fill this
void, a novel clonal complex multiplex PCR (CC M-PCR) was developed in the present study.
The CC M-PCR targets virulence genes specific to the major clonal complexes (CCs) of HAMRSA
and CA-MRSA in the United States. The CC M-PCR was used to characterize MRSA
isolates from 67 presumptive MRSA positive nasal swabs taken upon admission to the ICUs at
The Penn State Milton S. Hershey Medical Center. A majority (41/67) of the isolates were
correctly identified as CC 5 strains, the primary cause of HA-MRSA in the northeastern U.S. The
remaining isolates represented CCs 1, 8, 30, 45, 59, 133, and 5 isolates were identified as not
being S. aureus. A reliable means for the rapid detection and characterization of MRSA strains is
now critical due to CA-MRSA strains causing an increasing number of infections in healthcare
settings. The CC M-PCR method developed in the present study can serve as a rapid screening
method to detect which clonal complex a MRSA isolate belongs to before it is subsequently
subtyped to the strain level using more sophisticated, but more time-consuming molecular
methods.
