Lyme disease, although interesting biologically, is equally fascinating from a sociologic perspective. Understanding why some portray it as “one of the most controversial illnesses in the history of medicine” requires an understanding of the disease, its history, and its context.

Fungi are common pathogens among critically ill or immunosuppressed patients. In the past 15 years safer and/or more bioavailable formulations of older antifungal agents (eg, itraconazole oral solution, lipid amphotericin B formulation) have been marketed. A new class of antifungal agents—the echinocandins—has been developed and now contains 3 agents. In addition, 2 compounds—voriconazole and posaconazole—have been added to the triazole class of agents in this decade.

Health care–associated infections (HAIs) are an important cause of morbidity and mortality, and place a significant economic burden on the health care system. An estimated 1.7 million HAIs, or 4.5 infections per 100 hospital admissions, occurred in the United States in 2002, resulting in nearly 100,000 deaths.

Treatment selection for Clostridium difficile infection (CDI) has become more complex despite the lack of new FDA-approved treatments. Two investigational agents show promise for reduction of the high rate of CDI recurrence; fidaxomicin—a poorly absorbed macrocyclic antimicrobial agent—and IV monoclonal antibodies directed at toxins A and B.

According to a 2007 study by the Association for Professionals in Infection Control and Epidemiology (APIC), 1.2 million US hospital patients may be infected with methicillin-resistant Staphylococcus aureus (MRSA) each year; and up to 119,000 patients may die from MRSA.

The emergence of resistant organisms has been a major therapeutic challenge for clinicians. One of the most problematic resistant pathogens is methicillin-resistant Staphylococcus aureus (MRSA). Methicillin resistance in S. aureus infections is mediated by the mecA gene, which encodes a penicillin-binding protein that has low affinity for β-lactam–type antibiotics and renders all commercially available β-lactams inactive.

Fluoroquinolones are potent, broad-spectrum antibiotics that are widely used to treat grampositive and gram-negative bacterial infections. Increasingly, they are being used for treatment of Mycobacterium tuberculosis, generally as second-line agents against multidrug-resistant (MDR) organisms. Because fluoroquinolones are effective bactericidal compounds, ongoing discussions and clinical trials are centered on moving them into first-line tuberculosis (TB) regimens.

The following review summarizes some of the key clinical themes that emerged in HIV treatment during the past year, with a focus on those that have a direct clinical application. Additionally, the US Department of Health and Human Services (DHHS) Guidelines for the Use of Antiretroviral Agents in HIV1- Infected Adults and Adolescents underwent substantial revisions, and the changes comprise most of the material in the accompanying tables.

The initiation of the antibiotic era 7 decades ago led to extraordinary progress in the treatment of serious and often fatal bacterial infections. In the early part of that era, however, there was a lack of appreciation for mutation, genetic transfer, and Darwinian selection of resistant bacteria by the use (and overuse) of antibiotics. As a result, for decades, physicians were relatively indiscriminate in routinely using antibiotics for even trivial infections (many caused by viruses), which led to inappropriate expectations of their use by patients.

This editorial review is intended to be a reference to describe the potential in vivo activity of various antimicrobial agents when the identity of the infecting organism is known. Because the early initiation of appropriate therapy has been noted to improve clinical outcomes, empiric therapy frequently demands powerful broad-spectrum antimicrobial agent(s) until the specific infecting bacteria has been identified.