The effect of cephalosporin resistance on mortality in adult patients with nonmeningeal systemic pneumococcal infections.
OBJECTIVE
To evaluate the clinical relevance of cephalosporin (ceftriaxone/cefotaxime) resistance among patients with nonmeningeal systemic pneumococcal infection.


METHODS
From January 1994 to October 2000, we prospectively studied 522 episodes of nonmeningeal systemic pneumococcal infections (448 pneumonias) in 499 adults who were treated according to hospital guidelines. In vitro antibiotic susceptibility, as the minimum inhibitory concentration (MIC), was determined by microdilution method. The MIC methods and breakpoints (cutoffs) were established by the National Committee for Clinical Laboratory Standards.


RESULTS
Of the 522 pneumococcal strains, 413 strains (79%) were susceptible to ceftriaxone/cefotaxime, MIC < or =0.5 microg/mL; 79 (15%) were intermediate, MIC = 1 microg/mL; and 30 (6%) were resistant, MIC = 2 microg/mL. After adjusting for several variables, including pneumococcal serogroups/serotypes, infections due to nonsusceptible (intermediate and resistant) pneumococcal strains were independently associated with prior antibiotic therapy, with an odds ratio of 5.9 (95% confidence interval: 2.6 to 13.6). Thirty-day mortality among the 185 patients who were treated with ceftriaxone (1 g/d) or cefotaxime (1.5 g every 8 hours) did not differ by cephalosporin susceptibility: 18% (26/148) among those with susceptible organisms, 13% (3/24) with intermediate organisms, and 15% (2/13) in resistant cases (P = 0.81).


CONCLUSIONS
Ceftriaxone or cefotaxime were effective in treating patients with nonmeningeal systemic pneumococcal infections caused by strains with MIC < or =2 microg/mL. These results support the newly established ceftriaxone/cefotaxime MIC breakpoints (cutoffs) for nonmeningeal pneumococcal infections.
Pallares
Roman
R
Infectious Disease Service, Hospital Bellvitge and University of Barcelona, Spain. rpallares@bell.ub.es
Capdevila
Olga
O
Liñares
Josefina
J
Grau
Imma
I
Onaga
Hisao
H
Tubau
Fe
F
Schulze
Marco H
MH
Hohl
Peter
P
Gudiol
Francesc
F
D000328:Adult; D000368:Aged; D016470:Bacteremia / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality*; D002439:Cefotaxime / Q000008:administration & dosage; D002443:Ceftriaxone / Q000008:administration & dosage; D018550:Cephalosporin Resistance; D015331:Cohort Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D011008:Pneumococcal Infections / Q000175:diagnosis / Q000188:drug therapy* / Q000401:mortality*; D011336:Probability; D011446:Prospective Studies; D018570:Risk Assessment; D013296:Streptococcus pneumoniae / Q000187:drug effects*; D016019:Survival Analysis; D016896:Treatment Outcome
D002443:Ceftriaxone; D002439:Cefotaxime