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.

Rifaximin (Xifaxan - Salix), a non-absorbed oral antibiotic derived from rifampin (Rifadin, and others), has been approved by the FDA for treatment of travelers' diarrhea caused by noninvasive strains of Escherichia coli in patients 12 years of age or older. It has been available in Europe since 1987.

The FDA has approved rifamycin (Aemcolo – Cosmo/ Aries), a minimally absorbed oral antibiotic, for treatment of adults with travelers' diarrhea (TD) caused by noninvasive strains of Escherichia coli. It is not recommended for treatment of diarrhea that is complicated by fever and/or bloody stools. Topical and injectable formulations of rifamycin have been used in Europe for other indications for many years.

Gemifloxacin (Factive - Oscient), a new oral fluoroquinolone antibiotic, has been approved by the FDA for 5 days' treatment of acute bacterial exacerbations of chronic bronchitis (ABECB) and 7 days' treatment of mild to moderate community-acquired pneumonia (CAP) in adults. For the next 6-8 months it will only be available, presumably for commercial reasons, in states east of the Rocky Mountains.

The most common cause of travelers' diarrhea, usually a self-limited illness without fever lasting several days, is infection with noninvasive enterotoxigenic (ETEC) or enteroaggregative (EAEC) strains of Escherichia coli. Campylobacter, Shigella, Salmonella, Aeromonas, viruses and parasites are less common.

A study now available on the web site of The New England Journal of Medicine (LY Park-Wyllie et al. Outpatient gatifloxacin therapy and dysglycemia in older adults. www.nejm.org, published online March 1, 2006) reports an increased risk of hypoglycemia (RR 4.3) and hyperglycemia (RR 16.7) with use of gatifloxacin (Tequin), a fluoroquinolone antibiotic. The Medical Letter published an article on this risk in 2003 (vol. 45, page 64); at that time the extent to which other fluoroquinolones carried the same risk was unclear. The recent report indicates that, except for a slightly increased...

The FDA has approved ceftolozane/tazobactam (Zerbaxa – Cubist), a combination of a new cephalosporin antibiotic and a beta-lactamase inhibitor, for intravenous treatment of complicated urinary tract and intra-abdominal infections in adults.

Doripenem (Doribax - Ortho-McNeil Janssen), an intravenous (IV) carbapenem antibiotic with a spectrum of activity similar to that of imipenem and meropenem, has been approved by the FDA for treatment of complicated intra-abdominal and urinary tract infections. Use of doripenem for treatment of nosocomial pneumonia, including ventilator-associated pneumonia, is still under FDA review.

Lefamulin (Xenleta – Nabriva), a semisynthetic pleuromutilin antibiotic, has been approved by the FDA for IV and oral treatment of community-acquired bacterial pneumonia (CABP) in adults. It is the first systemic pleuromutilin antibiotic to be approved in the US; retapamulin (Altabax), a 1% topical ointment for treatment of impetigo, was approved in 2007.

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.