colleagues conclude that the risks of severe maternal morbidity associated with planned cesarean delivery are higher than those associated with planned vaginal delivery. However, a cross-sectional study of associations is nondirectional and one cannot infer either the presence of causality or its direction.During the 14-year study period, the rate of cesarean deliveries was increasing and morbidity was probably decreasing. Associations between 2 heterogeneous data sets are not meaningful. One needs data from a recent homogeneous time period to produce statistical associations that are relevant for current practice.Finally, the authors acknowledge that although the morbidity rate differences were statistically significant, the absolute differences were small. The authors do not state which, if any, of these small differences were clinically significant. My second concern is the authors' recommendation that cefazolin and gentamicin should be used to treat cases in which Gram's staining does not show bacteria. Most treatment recommendations for this scenario include a third-generation cephalosporin and vancomycin for empiric coverage of the most common bacterial pathogens. Neisseria gonorrhoeae would also be covered by this broader regimen; it is a common cause of septic arthritis in patients at risk for sexually transmitted infections. With the rising incidence of gonorrhea in Canada 4 and the frequency of a negative result of Gram's staining with gonococcal arthritis, this organism should at least be considered when treating septic arthritis.
Vincent V. Richman PhD
Cheryl Main MD BScMedical Microbiologist Hamilton Health Sciences Hamilton, Ont.
[The authors respond:]We thank Cheryl Main for her comments on the antimicrobial coverage for both gram-positive and gram-negative septic arthritis that we recommended in our article. 1 Our review focused on nongonococcal septic arthritis in patients with pre-existing inflammatory arthritis, and space constraints meant that we could not elaborate on many special circumstances.Unfortunately, the literature on community-acquired gram-positive septic arthritis in this population is limited. One case series of 59 patients with septic arthritis (in which 15 of the cases were due to MRSA and 44 were not) includes several patients with pre-existing rheumatic disease but does not provide details on the nature of their rheumatic disease.2 The authors of this case series suggest considering empiric treatment for MRSA infection in patients with septic arthritis if there are risk factors such as recent admission to hospital, known infection or colonization with MRSA, multiple comorbidities in addition to the rheumatic disease, injection drug use or residence in communities known to have a high prevalence of communityacquired MRSA infections. These suggestions are consistent with our interpretation of the guidelines referenced by Main.3,4 Hawkes suggests that people of First Nations or African-American heritage, athletes who participate in contact sports, injection drug users, men w...