The FDA has approved Vowst (Seres Therapeutics/Nestle HealthScience), an oral capsule containing live fecal microbiota spores, for prevention of additional recurrences of Clostridioides difficile infection (CDI) in adults. Vowst is the first orally administered microbiota-based treatment to be approved for this indication. A rectally-administered live fecal microbiota-based suspension (Rebyota) was approved in 2022 for the same indication. Neither product is approved for acute treatment of CDI.

The FDA has approved Rebyota (Ferring), a rectally-administered, live fecal microbiota suspension, for prevention of additional recurrences of Clostridioides difficile infection (CDI) following antibiotic treatment for a recurrent episode of CDI in adults. Rebyota is the first microbiome-based treatment to be approved for this indication. It is not approved for initial treatment of CDI. Fecal microbiota transplantation (FMT) has been used in patients with multiple CDI recurrences.

This article includes recommendations for management of most sexually transmitted infections (STIs) other than HIV and viral hepatitis. Some of the indications and dosages recommended here have not been approved by the FDA (see Table 1).

Clostridioides (formerly Clostridium) difficile infection (CDI) is the most common infectious cause of healthcare-associated diarrhea in adults. Guidelines on management of CDI have recently been updated.

Treatment of community-acquired pneumonia (CAP) is usually empiric, with selected antibiotic regimens directed against some of the most common causative pathogens. Recommended empiric regimens are listed in Table 2; recommended antibiotic dosages for treatment of CAP are listed in Tables 3 and 4. Joint guidelines for treatment of CAP by the American Thoracic Society and the Infectious Diseases Society of America (ATS/IDSA) were updated in 2019.

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 vancomycin oral solution (Firvanq – Cutis Pharma) for treatment of Clostridium difficile-associated diarrhea and enterocolitis caused by Staphylococcus aureus, including methicillin-resistant strains (MRSA).

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 secnidazole oral granules (Solosec – Symbiomix/Lupin) for single-dose treatment of bacterial vaginosis (BV) in adult women.

Proton pump inhibitors (PPIs), which are used for treatment of gastroesophageal reflux disease (GERD) and for prevention of upper gastrointestinal adverse effects caused by NSAIDs and aspirin, are one of the most commonly prescribed classes of drugs in the US. All PPIs are similarly effective and generally well tolerated, but their long-term use has been associated with a number of safety concerns. Recommendations addressing these concerns have recently been published.

About 50% of the world’s population is infected with Helicobacter pylori. These gastric bacteria can cause chronic inflammation and have been associated with development of gastritis, peptic ulcer disease, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Eradication of H. pylori can promote gastric healing, prevent recurrence of duodenal and gastric ulcers, and reduce the incidence of gastric cancer. Guidelines for treatment of H. pylori infection were updated recently.

The FDA has approved the fully human monoclonal antibody bezlotoxumab (Zinplava – Merck) for use with antibacterial drug treatment to reduce recurrence of Clostridium difficile infection (CDI) in adults with CDI at high risk for recurrence. It is the first drug to be approved for this indication.

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.

The FDA has approved fidaxomicin (Dificid – Optimer), a new oral macrolide antibiotic, for treatment of Clostridium difficile-associated diarrhea in patients ≥18 years old. The incidence and severity of C. difficile infection (CDI) have increased in recent years with the emergence of an epidemic hypervirulent strain (NAP1/B1/027), possibly related to widespread use of fluoroquinolones.

Clostridium difficile infection (CDI) is the most common infectious cause of healthcare-associated diarrhea in adults. The incidence and severity of CDI have increased in recent years with the emergence of an epidemic virulent strain (NAP1/BI/027). Common risk factors include admission to a healthcare facility, increasing age and severity of underlying illness, gastric acid suppression and exposure to antimicrobials, particularly clindamycin, ampicillin, cephalosporins or fluoroquinolones. Patients who develop CDI while receiving a precipitating antibiotic should have the antibiotic discontinued, if possible, or switched to another appropriate antimicrobial with a lower risk of CDI.

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.

Antimicrobial prophylaxis can decrease the incidence of infection, particularly surgical site infection, after certain procedures. Recommendations for prevention of surgical site infection are listed in the table that begins on page 48. Antimicrobial prophylaxis for dental procedures to prevent endocarditis is discussed in The Medical Letter 2007; 49:99.

(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.

In the recent Medical Letter article on the treatment of Clostridium difficile–associated disease (CDAD) we wrote: “Healthcare workers caring for patients with C. difficile infection should follow contact isolation precautions, especially use of gloves and hand washing with soap and water after glove removal. Alcohol-based products such as hand sanitizers will not eradicate C. difficile spores.”1 One reader pointed out that alcoholbased products do eradicate some C. difficile spores and have been invaluable against other pathogens.

In an unpublished study available as an abstract, both alcohol-based hand gels and chlorhexidine washes reduced the number of C. difficile spores on contaminated hands, but chlorhexidine was more effective (8 spores/cm2 remaining vs. 30-44 spores/cm2 with 3 formulations of alcohol-based hand gels).2 A previous study showed that chlorhexidine was not different from soap in removal of spores.3 Alcohol itself should have no effect on spores (purified spores are frequently stored in alcohol), but the mechanical action of washing hands with alcohol-based products may be effective in removing them. The CDC has recommended that healthcare workers caring for patients with known or suspected CDAD use contact precautions and perform hand hygiene with either an alcohol-based hand rub or soap and water, except in an outbreak setting, where exclusive use of soap and water should be considered.4

1. Treatment of Clostridium difficile–associated disease (CDAD). Med Lett Drugs Ther 2006; 48:89.

2. J Leischner et al. Effect of alcohol hand gels and chlorhexidine hand wash in removing spores of Clostridium difficile (CD) from hands. Intersci Conf Antimicrob Agent Chemother (ICAAC), Washington, DC 2005, abstract LB-29-2005.

3. K Bettin et al. Effectiveness of liquid soap vs. chlorhexidine gluconate for the removal of Clostridium difficile from bare hands and gloved hands. Infect Control Hosp Epidemiol 1994; 15:697.

4. CDC. Clostridium difficile information for healthcare providers (www.cdc.gov/ncidod/dhqp/id_CdiffFAQ_HCP.html; accessed January 22, 2007).

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The gram-positive anaerobic bacillus Clostridium difficile is the most common identifiable cause of antibiotic-associated diarrhea. The antibiotics most often implicated have been ampicillin, second and third generation cephalosporins, clindamycin and fluoroquinolones. The emergence in recent years of a new, more toxic epidemic strain (BI/NAP1), possibly related to widespread use of fluoroquinolones, has caused a marked increase in the incidence and severity of C. difficile-associated disease (CDAD).

Methicillin-resistant Staphylococcus aureus (MRSA) infections, which have been a concern for many years, previously occurred primarily in hospitalized patients and those recently treated with antibiotics. In the past few years, there has been an increasing incidence worldwide of community-associated (CA) MRSA infections in patients without recent antibiotic exposure or contact with the healthcare system.

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.

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.