Clinical

New drug choices emerging to battle antibiotic resistance


 

AT THE ANNUAL ADVANCES IN INTERNAL MEDICINE

 

SAN FRANCISCO – When the Infectious Diseases Society of America released the “Bad Bugs, No Drugs” report in 2004, its authors warned that effective antibiotics may not be available to treat seriously ill patients in the near future.

It also proposed legislative, regulatory, and funding solutions with a goal of developing and licensing 10 new antibiotics by the year 2020.

One such advancement was the Generating Antibiotics Incentives Now Act, which was signed into law in 2012 and created a designation for new antibiotics that are used to treat serious and/or life-threatening diseases due to certain pathogens. It also extends the patent life of these antibiotics and allows for fast-track Food and Drug Administration approval.

Dr. Kim S. Erlich, chief of staff at Mills Peninsula Medical Center, Burlingame, Calif.
Dr. Kim S. Erlich
“The reason for antibiotic resistance over time has largely been … the direct result of our antibiotic use both in humans and in animals,” Kim S. Erlich, MD, said at the UCSF Annual Advances in Internal Medicine meeting. “Many of these organisms have spread globally and are now part of normal flora, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE). It costs more across the board to take care of these patients, and they have higher mortality and higher morbidity.”

According to Dr. Erlich, chief of staff and medical director of infection control and antibiotic stewardship at Mills Peninsula Medical Center, Burlingame, Calif., increasingly common antibiotic-resistant pathogens besides MRSA and VRE include penicillin-resistant Streptococcus pneumoniae, extended-spectrum beta-lactamase–producing gram-negative rods, carbapenem-resistant Enterobacteriaceae (CRE), multidrug-resistant Mycobacterium tuberculosis, Salmonella enterica serotype Typhimurium DT 104, and drug-resistant Candida species.

Since 2010, several new antibiotics have been introduced to the market, including three second-generation lipoglycopeptide antibiotics with gram-positive coverage that are approved primarily for skin and soft tissue infections: dalbavancin (Dalvance), telavancin (Vibativ), and oritavancin (Orbactiv).

Compared with vancomycin, these new agents have more convenient dosing and a longer half life, “but they’re also more expensive,” said Dr. Erlich. Dalbavancin can be dosed once a week intravenously, telavancin can be dosed once daily intravenously, and oritavancin requires just one dose.

Another new agent is tedizolid phosphate (Sivextro), a second-generation oxazolidinone that is in the same drug class as linezolid (Zyvox). Tedizolid phosphate has gram-positive coverage including MRSA, but it is not approved for VRE. “It’s FDA approved for skin and soft-tissue infections (SSTI) but can be used for other locations as well,” Dr. Erlich said. “It features once-daily dosing IV or PO.”

Ceftaroline fosamil (Teflaro), ceftolozane/tazobactam (Zerbaxa), and ceftazidime/avibactam (Avycaz) are broad-spectrum cephalosporins with or without beta-lactamase inhibitors resulting in extended gram-negative coverage. FDA-approved indications include complicated urinary tract infections, complicated abdominal infections, SSTI, and pneumonia.

The primary advantage of these drugs, compared with other agents, is for multidrug-resistant gram-negative bacteria such as extended-spectrum beta-lactamase producers and CRE. “We’re not using a lot of these drugs in clinical practice, but they are available for patients with multidrug-resistant gram-negative rods who have no other options,” Dr. Erlich said.

Practical ways that clinicians can prevent antibiotic resistance include prescribing antibiotics only when necessary. “Be aware of local resistance patterns, avoid antibiotics for probable viral infections, use narrow-spectrum choices when possible, use shorter durations when appropriate, and consult published guidelines for optimal empiric antibiotic therapy,” Dr. Erlich advised.

In addition, “advocate infection control measures to keep patients from developing infections, including proper wound care, hand washing, respiratory etiquette, vaccinations, and social isolation for symptomatic individuals,” he noted.

Dr. Erlich reported having no relevant financial disclosures.
 
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