Urine nitrite not correlated with bacterial resistance to cephalosporins.

Previous research has failed to identify urine nitrite as a useful marker for bacterial resistance to trimethorprim/sulfamethoxazole (TMP/SMX). Evolving resistance to TMP/SMX has encouraged the use of alternate antibiotics, including first-generation cephalosporins. The objective of this study was to reanalyze the relationship between urine nitrite results and bacterial resistance, focusing on first-generation cephalosporins. This was a retrospective review of consecutive culture positive urinalyses collected from December 2002 to July 2003. The majority of the 642 cultures reviewed contained Esherichia coli (74%). Thirty-six percent (233/642) were nitrite positive. Ten percent (24/233) of the nitrite positive urines were resistance to first-generation cephalosporin (cefazolin). In the nitrite-negative group 15.0% (62/409) were resistant. This difference was not statistically significant. We conclude that the detection of urine nitrites should not influence the use of first-generation cephalosporins for urinary tract infection.