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.

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.

Inflammatory bowel disease (IBD) is generally classified as either Crohn’s disease (CD) or ulcerative colitis (UC). More detailed guidelines on their treatment are available from the American College of Gastroenterology.

Irritable bowel syndrome (IBS) is a common disorder, occurring in up to 15% of the US population; it is 2-2.5 times more frequent in women than in men. IBS is characterized by chronic, intermittent abdominal pain or discomfort accompanied by altered bowel habits. Since the underlying mechanisms of disease remain unclear, management of IBS focuses on symptom control.

The antibiotic aztreonam is now available as an inhalation solution (Cayston – Gilead) to improve respiratory symptoms in cystic fibrosis (CF) patients ≥7 years old colonized with Pseudomonas aeruginosa. It is the second inhaled antibiotic to be FDA-approved for this indication in CF patients; the aminoglycoside tobramycin (Tobi) was the first. Inhaled antibiotics offer the advantage of high airway concentrations while minimizing systemic side effects.

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.

Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) are common causes of peptic ulcer disease. Patients infected with Helicobacter pylori who take aspirin or another NSAID have an especially high risk. Drugs that have been tried for prevention of ulcers in patients taking NSAIDs including H₂-receptor antagonists, proton pump inhibitors (PPIs), aluminum- or magnesium-containing antacids, the prostaglandin misoprostol (Cytotec, and others), and antibiotics to eradicate H. pylori.

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Telavancin (Vibativ - Astellas and Theravance), a lipoglycopeptide derivative of vancomycin (Vancocin, and others), has received FDA approval for treatment of complicated skin and skin structure infections caused by susceptible gram-positive bacteria in adults.

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 pathogenesis of acne is multifactorial: follicular hyperkeratinization, bacteria, sebum production, androgens and inflammation all play a role. The gram-positive microaerophilic bacteria Propionibacterium acnes promote development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

Retapamulin (re-tap'-a-mue'-lin; Altabax - Glaxo SmithKline) is a topical antibiotic recently approved by the FDA for treatment of bullous and non-bullous impetigo due to Streptococcus pyogenes and methicillin-susceptible Staphylococcus aureus. It is available as a 1% ointment by prescription only.

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.

A new once-daily, low-dose oral formulation of doxycycline monohydrate (Oracea - CollaGenex) has been approved by the FDA for treatment of inflammatory papules and pustules associated with rosacea in adults.

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 this article.

The FDA has approved an extended-release formulation of minocycline (Solodyn - Medicis) for once-daily treatment of non-nodular moderate to severe acne.

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).

Telithromycin (Ketek) is an oral erythromycin derivative FDA-approved for treatment of mild to moderate community-acquired pneumonia, exacerbations of chronic bronchitis and acute bacterial sinusitis (Med Lett Drugs Ther 2004; 46:66). It is generally considered an alternative antibiotic because of its cost, potential for adverse effects including visual disturbances, exacerbation of myasthenia gravis, hepatotoxicity and drug interactions. A recent report (Ann Intern Med 2006; 144:415) described serious hepatotoxicity probably related to telithromycin in three patients, including one who died and another who needed a liver transplant. Many other oral antibiotics are available for treatment of community-acquired pneumonia, exacerbations of chronic bronchitis and acute bacterial sinusitis in adults (Med Lett Drugs Ther 2005; 47:78).

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 relative risk of hypoglycemia (RR 1.5) with levofloxacin (Levaquin), they do not. Gatifloxacin, levofloxacin, moxifloxacin (Avelox) and gemifloxacin (Factive) are more active than other quinolones against gram-positive organisms such as Streptococcus pneumoniae, including strains highly resistant to penicillin; they are sometimes called "the respiratory quinolones." Given the availability of other drugs with similar in vitro and clinical activity, there is no good reason to continue to use gatifloxacin.

Irritable bowel syndrome (IBS) is a common disorder, occuring in about 15% of the US population; it is 2-3 times more frequent in women than in men. IBS is characterized by chronic abdominal pain or discomfort and altered bowel habits.

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.

The pathogenesis of acne is multifactorial: follicular hyperkeratinization, Propionibacterium acnes bacteria, sebum production, androgens and inflammation have all been implicated. P. acnes, a gram-positive microaerophilic bacterium, plays an important role in the development of acne lesions by secreting chemotactic factors that attract leukocytes to the follicle, causing inflammation.

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.

Telithromycin (Ketek - Aventis) has been approved by the FDA for oral treatment of mild to moderate community-acquired pneumonia, acute exacerbations of chronic bronchitis and acute bacterial sinusitis in patients age 18 and older. The drug is the first in a new class of antibiotics, the ketolides, derived from the macrolide erythromycin. Telithromycin has been marketed in Europe since 2001.

Daptomycin (Cubicin - Cubist), a cyclic lipopeptide (a new class of antibiotics), has been approved by the FDA for intravenous (IV) treatment of complicated skin and skin structure infections. It is being promoted as a once-daily bactericidal alternative to vancomycin (Vancocin, and others) for methicillin-resistant Staphylococcus aureusinfections.