title: Risk factors for oxacillin/methicillin resistance in coagulase-negative staphylococci.
abstract: The clinical variables associated with isolation of oxacillin- and methicillin-resistant, coagulase-negative staphylococci (CNS) from blood cultures of hospitalized patients were studied. One hundred CNS strains (49 oxacillin-susceptible; 51 oxacillin-resistant) isolated consecutively from one of two or more sets of blood cultures were collected. Only two variables were independently associated with recovery of oxacillin/methicillin-resistant strains by a multivariate analysis: length of hospital stay > 10 days (OR 5.2, 95% CI = 1.7-15.7), and administration of antimicrobial agents in the previous 14 days (OR 4.5, 95% CI = 1.7-11.7). Analysis of the antibiotics administered indicated that only beta-lactams were associated with a statistically significant risk of resistance to oxacillin/methicillin (OR of beta-lactams vs no antibiotics = 6.94, 95% CI = 1.9-25.3; OR of non-beta-lactams vs no antibiotics = 2.64, 95% CI = 0.8-8.3). Length of hospital stay (especially > 10 days) and prior administration of antimicrobial agents (mainly beta-lactams) independently predicted the presence of oxacillin/methicillin-resistant CNS in blood cultures.
authors.affiliation: Laboratory of Microbiology, Hospital Clínic, Barcelona, Spain.
authors.forename: J A
authors.initials: JA
authors.lastname: Martínez
authors.forename: J
authors.initials: J
authors.lastname: Mensa
authors.forename: F
authors.initials: F
authors.lastname: Marco
authors.forename: M
authors.initials: M
authors.lastname: Almela
authors.forename: J
authors.initials: J
authors.lastname: Lopez
authors.forename: C
authors.initials: C
authors.lastname: Casals
authors.forename: E
authors.initials: E
authors.lastname: Soriano
authors.forename: M T
authors.initials: MT
authors.lastname: Jiménez de Anta
mesh_terms: D003428:Cross Infection / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008712:Methicillin / Q000627:therapeutic use*; D016106:Methicillin Resistance; D008875:Middle Aged; D010068:Oxacillin / Q000627:therapeutic use*; D010403:Penicillin Resistance; D010406:Penicillins / Q000627:therapeutic use*; D012307:Risk Factors; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000382:microbiology / Q000517:prevention & control*
chemical_list: D010406:Penicillins; D008712:Methicillin; D010068:Oxacillin