Antimicrobial susceptibility patterns of gram-negative rods causing antepartum pyelonephritis have shown little change over the last 15 years. Susceptibility patterns in 1992 to 1993 and 2004 to 2006 were similar, with 51% and 54% (respectively) of the Escherichia coli strains being resistant to ampicillin, according to Roberts and colleagues from Metrohealth Medical Center in Cleveland. However, E coli resistance to trimethoprim-sulfamethoxazole increased from 5% to 20%. No resistance to first-generation cephalosporins was reported. This study confirms that ampicillin is a poor choice for the treatment of antepartum pyelonephritis.
