Nouira S et al: Standard versus newer antibacterial agents in the treatment of severe acute exacerbation of chronic obstructive pulmonary disease: A randomized trial of trimethoprim-sulfamethoxazole versus ciprofloxacin. Clin Infect Dis 2010;51:143.
Rodriguez-Martinez JM et al: Plasmid-mediated quinolone resistance: An update. J Infect Chemother 2011;17:149.
Scheld WM: Maintaining fluoroquinolone class efficacy: Review of influencing factors. Emerg Infect Dis 2003;9:1.
Schmitz GR et al: Randomized controlled trial of trimethoprim-sulfamethoxazole for uncomplicated skin abscesses in patients at risk for community-associated methicillin-resistant Staphylococcus aureus infection. Ann Emerg Med 2010;56:283.
Strom BL et al: Absence of cross-reactivity between sulfonamide antibiotics and sulfonamide nonantibiotics. N Engl J Med 2003;349:1628.
Talan DA et al: Prevalence of and risk factor analysis of trimethoprim-sulfamethoxazoleand fluoroquinolone-resistant E. coli infection among emergency department patients with pyelonephritis. Clin Infect Dis 2008;47:1150.
Workowski KA et al: Sexually Transmitted Diseases Treatment Guidelines, 2015. MMWR Recomm Rep 2015;64(RR-03):1.
Ziganshina LE et al: Fluoroquinolones for treating tuberculosis (presumed drug sensitive). Cochrane Database Syst Rev 2013;(6):CD004795.
A fluoroquinolone that achieves good urinary and systemic levels (ciprofloxacin or levofloxacin) would be a reasonable choice for empiric treatment of this patient’s complicated urinary tract infection. Given the possibility of a fluoroqui-nolone-resistant organism, one dose of a parenteral agent such as ceftriaxone (given IV or IM) would be reason-able pending culture results confirming fluoroquinolone susceptibility. Her recent exposure to multiple courses of trimethoprim-sulfamethoxazole increases her chances of having a urinary tract infection with an isolate that is resis-tant to this antibiotic. The patient should be told to take the oral fluoroquinolone 2 hours before or 4 hours after her calcium supplement, as divalent and trivalent cations can significantly impair the absorption of oral fluoroquinolones.
Camille E. Beauduy, PharmD, & Lisa G. Winston, MD*
A 60-year-old man presents to the emergency department with a 2-month history of fatigue, weight loss (10 kg), fevers, night sweats, and a productive cough. He is currently living with friends and has been intermittently homeless, spending time in shelters. He reports drinking about 6 beers per day. In the emergency department, a chest x-ray shows a right apical infiltrate. Given the high suspicion for pulmonary tuberculosis, the patient is placed in respiratory isolation. His first sputum smear shows many acid-fast bacilli, and an HIV test returns with a positive result. What drugs should be started for treatment of presumptive pulmonary tubercu-losis? Does the patient have a heightened risk of developing medication toxicity? If so, which medication(s) would be likely to cause toxicity?