The FDA has approved the new aminoglycoside antibiotic plazomicin (Zemdri – Achaogen) for IV treatment of adults with complicated urinary tract infections (cUTIs). Plazomicin is active against multi-drug- resistant Enterobacteriaceae, including strains resistant to other aminoglycosides.

Bedaquiline (bed ak' wi leen; Sirturo – Janssen), a diarylquinoline antimycobacterial, has been given accelerated approval by the FDA as an orphan drug for use in addition to other drugs for treatment of adults with multidrug-resistant pulmonary tuberculosis (MDR-TB). It is the first drug approved specifically to treat MDR-TB.

Ciprofloxacin, previously available orally (Cipro - Medical Letter, 30:11, 1988) and for ophthalmic use (Ciloxan - Medical Letter, 33:52, May 31, 1991), is now the first fluoroquinolone antibiotic to become available in the USA in an intravenous (IV) formulation. Cipro I.V. (Miles) is being promoted as an alternative to third-generation cephalosporins, aminoglycosides, and other drugs used for treatment of serious infections.

View Table: Mechanisms of Drug Interactions

Ciprofloxacin hydrochloride (Cipro - Miles), a synthetic antibacterial agent, was recently marketed in the USA for oral treatment of a wide variety of infections. Ciprofloxacin is the second fluoroquinolone to become available in this country; norfloxacin (Noroxin - Medical Letter, 29:25, 1987) is marketed only for treatment of urinary tract infections. Fluoroquinolones are more potent and have a much broader spectrum of activity than older quinolones such as nalidixic acid (NegGram).

Tuberculosis (TB) is still a common cause of death worldwide, and the prevalence of drug-resistant TB poses challenges to its treatment and control. Guidelines with detailed management recommendations are available from the American Thoracic Society, Centers for Disease Control and Prevention (CDC) and Infectious Diseases Society of America (IDSA).

Since the last Medical Letter review of cephalosporin antibiotics (volume 25, page 57, 1983), many new cephalosporins have become available in the USA.

The choice of drugs for treatment of pneumonia depends on the most likely pathogens causing the infection and local antimicrobial resistance patterns. Factors such as severity of illness, presence of co-morbid conditions and whether the infection is community or hospital-acquired also need to be considered.

Antimicrobial prophylaxis can decrease the incidence of postoperative surgical site infection after some procedures. Since the last Medical Letter article on this subject, consensus guidelines have been published. Recommendations for prophylaxis in specific surgical procedures are listed in Table 1.

The text that follows reviews some common bacterial infections and their empiric treatment pending the results of culture and susceptibility testing. The recommendations made here are based on the results of susceptibility studies, clinical trials, and the opinions of Medical Letter reviewers. Tables 1 and 2 list the usual dosages of antibacterial drugs.