Send to

Choose Destination
Rev Med Inst Mex Seguro Soc. 2016 Jan-Feb;54(1):48-51.

[Methicillin resistance and vancomycin susceptibility pattern among blood isolates of Staphylococcus aureus].

[Article in Spanish; Abstract available in Spanish from the publisher]

Author information

Servicio de Infectología Adultos, Hospital de Infectología, Centro Médico Nacional La Raza, Instituto Mexicano del Seguro Social, Distrito Federal, México.


in English, Spanish


Staphylococcus aureus is capable of acquiring resistance against all antimicrobial agents. Vancomycin has been the cornerstone therapy for serious methicillin-resistant S. aureus infections. However, vancomycin treatment failures have been reported.


From March to August 2010, S. aureus blood isolates were included to determine methicillin-resistance and the vancomycin susceptibility by using a standard microdilution method. To detect methicillin-resistance, a Mueller-Hinton agar plate added with oxacillin 4 µg/mL and 2 % NaCl, and an agglutination test were used. Growth of S. aureus on the agar plate and/or reactive agglutination defined a methicillin-resistant organism. Vancomycin susceptibility was assessed by determining the minimal inhibitory concentration (MIC) in Muelller-Hinton agar plates prepared with dilutions ranging from 16 to 0.5 µg/mL.


A total of 25 blood-isolates of S. aureus were included. A 60 % was methicillin-resistant. All isolates were vancomycin-susceptible (MIC ≤ 2 µg/mL) showing the next MICs distribution: 48 % ≤ 0.5 µg/mL; 44 % 1 µg/mL, and 8 % 2 µg/mL.


The high proportion of methicillin-resistance among S. aureus and the presence of vancomycin susceptible phenotypes (MIC of 2 µg/mL) not only claim for an enforcement of standard precautions and antimicrobial control, but also for a regular surveillance of vancomycin susceptibility pattern using a reference method.


Methicillin resistant Staphylococcus aureus; Vancomycin resistance

[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center