isolates from both children and adults were more often MDR, but the rates did not differ substantially (76% vs.
Fifty-three (88%) of 60 invasive disease isolates and 501 (95%) of 525 SSTI isolates had PFGE subtypes that could be categorized into PFTs that have been associated with HA-MRSA
disease (USA100, USA200, USA500-800) or CA-MRSA (USA300 and USA400) (30).
Of the remaining 724 MRSA cases, 405 (56%) were HA-MRSA
infection and 44% were CA-MRSA infection.
Using PFGE to compare CA-MRSA isolates with representative HA-MRSA
isolates from both France (24 isolates) and the United States (33 isolates), we found that the last isolates grouped into lineages that clearly differed from any of the CA-MRSA isolates of the same continent (not shown).
2, the NYU Langone team found that the presence or absence of dueling toxins, or bacterial poisons, appears to explain the major difference between HA-MRSA
, and its less virulent and more common, community based-based cousin, CA-MRSA, the two main types of MRSA infection.
Considering the 95% confidence interval overlap, no significant differences occurred between the mean 6 values for the HA-MRSA
enters the community and CA-MRSA emerges in health-care facilities, distinguishing these two strains is becoming increasingly difficult (McCarthy et al.
7) Distinguishing between CA-MRSA and HA-MRSA
is not always straightforward, since colonization might have been present over a period of time, thus obscuring the source.
During the period from 1997 to 2003, the predominant isolate was the HA-MRSA
clonal group USA100, an MDR strain (i.
The only HA-MRSA
bloodstream infection was caused by a USA300-related strain.
CA-MRSA, along with HA-MRSA
, has emerged as a growing world-wide problem in the past decade(s).
Genetic analysis using techniques such as pulse field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST), and antibiograms demonstrate that CA-MRSA isolates are distinct strains emerging de novo from CA-methicillin-susceptible isolates rather than from HA-MRSA
isolates eminating from hospital settings (Mongkolrattanothai et al, 2003).