Use of molecular epidemiology to monitor the nosocomial dissemination of methicillin-resistant Staphylococcus aureus in a University Hospital from 1991 to 2001

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) has been the cause of major outbreaks and epidemics among hospitalized patients, with high mortality and morbidity rates. We studied the genomic diversity of MRSA strains isolated from patients with nosocomial infection in a University Hospital from 1991 to 2001. The study consisted of two periods: period I, from 1991 to 1993 and period II from 1995 to 2001. DNA was typed by pulsed-field gel electrophoresis and the similarity among the MRSA strains was determined by cluster analysis. During period I, 73 strains presented five distinctive DNA profiles: A, B, C, D, and E. Profile A was the most frequent DNA pattern and was identified in 55 (75.3%) strains; three closely related and four possibly related profiles were also identified. During period II, 80 (68.8%) of 117 strains showed the same endemic profile A identified during period I, 18 (13.7%) closely related profiles and 18 (13.7%) possibly related profiles and, only one strain presented an unrelated profile. Cluster analysis showed a 96% coefficient of similarity between profile A from period I and profile A from period II, which were considered to be from the same clone. The molecular monitoring of MRSA strains permitted the determination of the clonal dissemination and the maintenance of a dominant endemic strain during a 10-year period and the presence of closely and possibly related patterns for endemic profile A. However, further studies are necessary to improve the understanding of the dissemination of the endemic profile in this hospital.

Longitudinal Study of the Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus at a University Hospital

“…Our comprehensive study, which included all MRSA isolates detected from patients over 12 years at a university hospital, allowed us to create a unique picture of the changes in the local epidemiology. The existence of a predominant clone that accounted for roughly two-thirds of the isolates has been described previously (3,12). Our data demonstrate that the time needed for a strain to become predominant can be as short as 4 to 5 years.…”

“…In other studies, isolates were only randomly typed (3,12,30) or, following certain criteria (24,32), only selected isolates were typed. Our comprehensive study, which included all MRSA isolates detected from patients over 12 years at a university hospital, allowed us to create a unique picture of the changes in the local epidemiology.…”

Evolution of methicillin-resistant Staphylococcus aureus clones in Latin America

“…Twenty studies described clonal MRSA in Brazil (Figure 3). 8,[16][17][18][23][24][25][27][28][29][30]34,37,40,42,43,[46][47][48]50 The earliest publication from Brazil described the inter-hospital spread of a single MRSA clone in eight of nine hospitals under surveillance in Sao Paulo between 1990 and 1992. 8 A year later, MRSA isolates collected from five large teaching hospitals in different parts of Brazil shared a common PFGE pattern, again indicating that a single, epidemic clone (the 'Brazilian' clone) was widespread in Brazil.…”

Mortality among Burned Colonized/Infected by <i>Staphylococcus</i><i> </i><i>aure</i><i>u</i><i>s</i><i> </i>Sensitive and Resistant to Methicillin: Meta-Analysis

“…Among the microorganisms involved in these patients, bacteria are the most common and major cause of death in burned patients is bacterial infection [13]. However, factors associated with the patient and the microorganism, such as age, extent of thermal damage, the depth of the burn, the type and number of microorganisms, production of toxins and enzymes, determines the probability of invasive infection of the wound [14,15].…”