2First-generation cephalosporins: cefazolin for parenteral administration; cefadroxil or cephalexin for oral administration. Second-generation cephalosporins: cefuroxime for par enteral administration; cefaclor, cefuroxime axetil, cefprozil for oral administration. Third-generation cephalosporins: ceftazidime, cefotaxime, ceftriaxone for parenteral admin istration; cefixime, cefpodoxime, ceftibuten, cefdinir, cefditoren for oral administration. Fourth-generation cephalosporin: cefepime for parenteral administration. Cephamycins: cefoxitin and cefotetan for parenteral administration. 3Quinolones: ciprofloxacin, gemifloxacin, levofloxacin, moxifloxacin, norfloxacin, ofloxacin. Norfloxacin is not effective for the treatment of systemic infections. Gemifloxacin, levofloxacin, and moxifloxacin have excellent activity against pneumococci. Ciprofloxacin and levofloxacin have good activity against Pseudomonas aeruginosa. 4Macrolides: azithromycin, clarithromycin, dirithromycin, erythromycin. 5Generally, streptomycin and gentamicin are used to treat infections with Gram-positive organisms, whereas gentamicin, tobramycin, and amikacin are used to treat infections with Gram-negatives. 6Carbapenems: doripenem, ertapenem, imipenem, meropenem. Ertapenem lacks activity against enterococci, Acinetobacter, and P aeruginosa. 7Antipseudomonal penicillin: piperacillin, piperacillin/tazobactam, ticarcillin/clavulanic acid. 8See footnote 3 in Table 51–2 for guidelines on the treatment of penicillin-resistant pneumococcal meningitis. 9Parenteral nafcillin or oxacillin; oral dicloxacillin. 10There is no regimen that is reliably bactericidal for vancomycin-resistant enterococcus for which there is extensive clinical experience; daptomycin has bactericidal activity in vitro. Regimens that have been reported to be efficacious include nitrofurantoin (for urinary tract infection); potential regimens for bacteremia include daptomycin, linezolid, and dalfopristin/quinupristin. 11Echinocandins: anidulafungin, caspofungin, micafungin.
TABLE 51–2 Empiric antimicrobial therapy based on site of infection.
Child H influenzae, pneumococcus, Ceftriaxone or cefotaxime ± Chloramphenicol, meropenem meningococcus vancomycin3 1See footnote 9, Table 51–1. 2See footnote 2, Table 51–1. 3When meningitis with penicillin-resistant pneumococcus is suspected, empiric therapy with this regimen is recommended. 4Erythromycin, clarithromycin, or azithromycin (an azalide) may be used. 5Quinolones used to treat pneumonococcal infections include levofloxacin, moxifloxacin, and gemifloxacin. 6Adjunctive immunomodulatory drugs such as drotrecogin-alfa can also be considered for patients with severe sepsis.
determine the cause of failure. Errors in susceptibility testing are rare, but the original results should be confirmed by repeat testing. Drug dosing and absorption should be scrutinized and tested directly using serum measurements, pill counting, or directly observed therapy.