Patients who receive pretravel advice can reduce their risk for many travel-related conditions. Vaccines recommended for travelers are reviewed in a separate issue.

Eravacycline (Xerava – Tetraphase), a new synthetic tetracycline antibiotic, has been approved by the FDA for IV treatment of complicated intra-abdominal infections (cIAIs) in adults. Eravacycline is structurally similar to tigecycline (Tygacil, and generics), a broad-spectrum tetracycline approved by the FDA for IV treatment of complicated skin and skin structure infections, complicated intra-abdominal infections, and community-acquired pneumonia. A higher rate of mortality has been reported with use of tigecycline compared to other antibacterial drugs; it should be used only when no suitable alternative is available.

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.

The FDA has approved a fixed-dose combination of meropenem, a carbapenem antibiotic, and vaborbactam, a new beta-lactamase inhibitor (Vabomere – Melinta), for IV treatment of adults with complicated urinary tract infections (UTIs) that are proven or strongly suspected to be caused by Escherichia coli, Klebsiella pneumoniae, or Enterobacter cloacae spp. complex. Meropenem (Merrem, and generics) has been approved for years for treatment of complicated skin and skin structure infections, intra-abdominal infections, and bacterial meningitis. Resistance to meropenem and other carbapenems, mainly due to production of carbapenemases and other extended-spectrum beta-lactamases (ESBLs), has been increasing worldwide, particularly among Enterobacteriaceae. Vabomere is the first carbapenem/beta-lactamase inhibitor combination to be marketed in the US.

The FDA has approved delafloxacin (Baxdela – Melinta), an anionic fluoroquinolone antibiotic, for oral and parenteral treatment of adults with acute bacterial skin and skin structure infections (ABSSSIs), including those caused by methicillin-resistant Staphylococcus aureus (MRSA). It is the first fluoroquinolone to be approved for treatment of MRSA.

Bacterial infections in adults are generally treated empirically, with the antibiotic covering most, but not all, of the potential causative pathogens. For some infections, culture and sensitivity testing can guide treatment, allowing for use of narrower-spectrum antibiotics. The recommended dosages and durations of antibiotic treatment for common respiratory, skin, and urinary tract infections are listed in Tables 1-3. Infectious disease experts now recommend shorter treatment durations for many infections to reduce the development of antimicrobial resistance and minimize adverse effects.

The FDA has approved ceftazidime/avibactam (Avycaz – Actavis) for IV treatment of complicated urinary tract and intra-abdominal infections in adults who have limited or no other treatment options. Ceftolozane/tazobactam (Zerbaxa – Cubist), another cephalosporin/beta-lactamase inhibitor combination, was approved in 2014.

Patients planning to travel to other countries often ask for information about prevention of diarrhea, malaria, and other travel-related conditions. Vaccines recommended for travelers based on their destination, length of stay, and planned activities were reviewed in a previous issue.

Probiotics are live, nonpathogenic microorganisms (usually bacteria or yeasts) marketed as dietary supplements. They have not been approved by the FDA for any indication. Since our last article on this subject, some new data have become available.

Antimicrobial prophylaxis can decrease the incidence of postoperative infection, particularly surgical site infection, after some procedures. Recommendations for such prophylaxis are listed in the table that begins on page 74. Antimicrobial prophylaxis for dental procedures to prevent endocarditis was recently discussed in The Medical Letter.

The most recent guidelines from the Infectious Diseases Society of America (IDSA) and its European counterpart on the choice of antimicrobials for treatment of uncomplicated urinary tract infections (UTIs) in non-pregnant women focus on the unnecessary use of fluoroquinolones to treat uropathogens that are increasingly becoming resistant to them. Resistance of Escherichia coli to ciprofloxacin in the US has increased from 3% in 2000 to 17.1% in 2010.

Patients planning to travel to other countries often ask for information about appropriate vaccines and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control and Prevention (CDC) at www.cdc.gov/travel. Guidelines are also available from the Infectious Diseases Society of America (IDSA).

A Medical Letter reader has asked us to review the safety of the fluoroquinolone antibiotic levofloxacin (Levaquin – Ortho-McNeil-Janssen), which has just been approved for generic use by the FDA and has been at the center of some recent lawsuits regarding the adequacy of its safety warnings.

The FDA has approved ceftaroline fosamil (Teflaro – Forest), an intravenous (IV) cephalosporin, for treatment of acute bacterial skin and skin structure infections, including those caused by methicillin-resistant Staphylococcus aureus (MRSA), and for treatment of community-acquired bacterial pneumonia in adults. It is the first beta-lactam antibiotic approved for treatment of MRSA.

The text below reviews some common bacterial infections and their treatment. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Patients planning to travel to other countries often ask physicians for information about appropriate vaccines and prevention of diarrhea and malaria. Guidelines are also available from the Infectious Diseases Society of America (IDSA).

Inflammatory bowel disease (IBD) is either Crohn's disease or ulcerative colitis. Drug selection is guided by disease type (Crohn's versus ulcerative colitis), severity and location and whether the goal is induction or maintenance of remission. Table 1 on page 66 lists the drugs used to treat IBD with their formulations and cost. Table 2 on page 68 lists the drugs of choice and their doses for different indications. Table 3 on page 71 lists the drugs' adverse effects and recommendations for monitoring. More detailed guidelines are available from the American College of Gastroenterology.

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.

(Vol. 49, p. 66, August 13, 2007) A reader has pointed out that Saccharomyces boulardii is not a separate species, but a strain of Saccharomyces cerevisiae. S. cerevisiae (including S. boulardii) has been reported to cause systemic infection after oral ingestion in both immunocompromised patients and healthy hosts (MJ McCullough et al. J Clin Microbiol 1998; 36:2613).

Probiotics are live, nonpathogenic microorganisms (usually bacteria or yeasts) that have been used for centuries for their potential health benefits. They are currently marketed for prevention and treatment of a variety of disorders, including diarrhea, irritable bowel syndrome and inflammatory bowel disease.

Information about empirical treatment of bacterial infections, emerging trends in antimicrobial resistance, new drugs and new data about older drugs continue to become available. Usual pathogens and empiric treatment for some common types of infections are summarized in the text and a table listing the drugs of choice and alternatives for each pathogen begins on page 40. The recommendations made here are based on the results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants.

Patients planning to travel to other countries often ask physicians for information about immunizations and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control and Prevention at 877-FYI-TRIP (877-394-8747) or www.cdc.gov/travel.

Tigecycline (Tygacil - Wyeth), a derivative of minocycline, is a new intravenous (IV) antibiotic approved for treatment of complicated intra-abdominal and skin and skin-structure infections.

Patients planning to travel to other countries often ask physicians for advice about immunizations and prevention of diarrhea and malaria. More detailed advice for travelers is available from the Centers for Disease Control (CDC) at 877-FYI-TRIP (877-394-8747) or www.cdc.gov/travel. Recommendations for the treatment of parasitic diseases are available in the public reading room of The Medical Letter's web site.

New drugs for bacterial infections and new information about older drugs continue to become available. Empirical treatment of some common bacterial infections is discussed in this article. A table listing the drugs of choice and alternatives for each pathogen begins on page 18. These recommendations are based on results of susceptibility studies, clinical trials and the opinions of Medical Letter consultants. Local resistance patterns should be taken into account. Trade names are listed on page 24.

New drugs for treatment of bacterial infections and new information about older drugs continue to become available. Empirical treatment of some infections is discussed and a table listing the drugs of choice and alternatives for each pathogen are contained in this article. These recommendations are based on results of susceptibility studies, clinical trials and opinions of Medical Letter consultants. Local resistance patterns should be taken into account.

Since The Medical Letter last reviewed the choice of drugs for treatment of bacterial infections, a few new drugs and some new information about older drugs have become available.