Susceptibilidad antimicrobiana de Staphylococcus aureus sensible, con sensibilidad "BORDERLINE" y resistentes a la meticilina
Mendoza Ticona, Carlos Alberto *;
Velasquez Talavera, Renato **; Mercado Diaz, Ludwig **; Ballon
Echegaray, Jorge **; Maguiña Vargas, Ciro ***.
** Laboratorio de Análisis Clínicos de la Facultad de Medicina de la Universidad Nacional de San Agustín de Arequipa.
***Instituto de Medicina Tropical Alexander Von Humboltd. Profesor Principal, Dpto. de Medicina. Facultad de Medicina. Universidad Peruana Cayetano Heredia
SUMMARY
Objective: To determine the susceptibility to different antibacterials of three categories of S. aureus according to its susceptibility to methicillin. Methods: 76 S. aureus
strains that colonized patients and health workers were isolated from
three Departments at Hospital Honorio Delgado in Arequipa, 36 of which
were susceptible to methicillin (MSSA), 15 had borderline susceptibility
(BORSA) and 25 where resistant to methicillin (MRSA). They underwent
antibiogram for 14 antibacterials. Results: The only
antibiotic to which all isolates were susceptible was vancomycin. MRSA
were resistant to all betalactamics except imipenem that obtained 64%
susceptibility. BORSA keep an 80% susceptibility to cephalotin and 100%
to imipenem. The antibiotics cephalotin, imipenem, ciprofloxacine,
cotrimoxazole, rifampicine, erithromycin, tetracycline, cloramphenicol,
lincomycin and gentamycin had variable susceptibilities (p<0.01)
among the three categories, a bigger proportion of MSSA were susceptible
to these antibiotics, less for BORSA and lesser for MSSA. The
multiresistant strains were more frequent in MRSA that in the other
groups (p < 0.01). Conclusions: There are S. aureus
strains in our environment with borderline susceptibility to
methicillin. There are differences in the susceptibility to any
antibacterials among the three groups of S. aureus; this
differences can lead to a more rational antibacterial therapy. We
should apply international recommendations for methicillin resistance
detection in every strain isolation. (Rev. Med. Hered. 2003; 14: 181-185).
KEY WORDS : Staphylococcus aureus, methicillin resistance, borderline susceptibility, antibacterial susceptibility.
