Do Antibiotic Combinations Prevent the Emergence of Resistant Organisms?

Abstract

Antibiotic combinations are often used in the therapy of infectious diseases to broaden the antibacterial spectrum and to enhance antimicrobial activity. Another potential reason for combination therapy is to reduce or prevent the emergence of resistant organisms during therapy. Antituberculous chemotherapy provides a classic example in which drug combinations have successfully prevented the emergence of drug-resistant organisms and improved clinical outcome. The purpose of this brief report is to review the success of combination therapy in preventing resistance in more common bacterial infections.The emergence of resistance during single-drug therapy is a well-documented clinical phenomenon, especially with the broad-spectrum ß-lactams against gram-negative bacilli. As with Mycobacterium tuberculosis, the resistant organisms are generally thought to be naturally occurring mutants selected by drug exposure. Because mutation frequencies appear to vary from 10-6 to 10-8, it is not surprising that emergence of resistant organisms observed clinically occurs primarily at sites of high organism density, such as the respiratory and urinary tracts.

Usnic acid-loaded biocompatible magnetic PLGA-PVA microsphere thin films fabricated by MAPLE with increased resistance to staphylococcal colonization

“…Despite its low effect on human cells, this modified surface has a proven impact on microorganism development. Since the risk of emerging multidrug-resistant pathogens is continuously growing due to the extensive use of antibiotics both in prophylaxis and long-term therapy, local delivery of antimicrobial substances from coated surfaces or devices are desirable [73]. One promising candidate is UA with the formula 2,6-diacetyl-7,9-dihydroxy-8,9bdimethyl-1,3(2H,9bH)-dibenzofurandione, a secondary lichen metabolite exhibiting antimicrobial activity against planktonic Gram-positive bacteria, including S. aureus, Enterococcus faecalis and E. faecium [74].…”

Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges

“…Experts have long debated whether the use of combination regimens of antibiotics could prevent the emergence of resistance among typical bacterial pathogens, as is clearly the case for Mycobacterium tuberculosis (tuberculosis [TB]) (267)(268)(269). However, there are few data to suggest that combination regimens can reduce the emergence of resistance in vivo, particularly for Gram-negative bacterial infections (268,270,271).…”