Key Point

Antibiotics do not create resistance when used for CRS, especially if treatment is culture-directed.

BOSTON—Antibiotic resistance is a growing problem, perpetuated by the indiscriminate and excessive use of antimicrobials. However, some conditions, especially chronic rhinosinusitis (CRS), may require extended and repeat courses of antibiotic therapy. How should clinicians proceed when treating patients with this condition? New research suggests that antibiotic treatment for CRS patients may not lead to resistance, especially if treatment is culture-directed rather than empirical.¹

Neil Bhattacharyya, MD, and Lynn J. Kepnes, RNP, performed a prospective analysis of 224 microbiologic cultures taken from 90 CRS patients. The study period was seven years, and patients received an average of 2.7 antibiotic courses or six weeks of treatment per year. Most patients (80% to 90%) received culture-directed therapy. According to Dr. Bhattacharyya, an Associate Professor of Otology and Laryngology at Harvard Medical School, antibiotic use among CRS patients does not always lead to antibiotic resistance, particularly if treatment is judicious.

AIMING AT THE RIGHT GERMS

Dr. Bhattacharyya isolated 429 organisms from the cultures, including 255 gram-positive organisms, 120 gram-negative organisms, 48 anaerobes, and six fungi. He examined whether there was a trend toward increasing antibiotic resistance in individual CRS patients, whether gram-positive or gram-negative germs acquired increasing resistance for individual patients, whether there was a shift from gram-positive to gram-negative organisms within individual patients, and whether gram-positive and gram-negative organisms (as a group) were acquiring increasing resistance. There was no statistically significant trend toward increasing resistance in individual patients or in groups of bacteria; in fact, there was a nonsignificant trend toward decreasing resistance. There was no shift from gram-positive to gram-negative organisms. However, gram-negative bacteria had 5.0 antimicrobial resistances, versus 1.7 resistances in gram-positive organisms. “This trend is serious,” explained Dr. Bhattacharyya, “because gram-negative bacteria are known for acquired resistance.”

Dr. Bhattacharyya believes that resistance in all bacteria types can be minimized by using culture-directed treatment for CRS patients whenever possible. Although antibiotics are FDA-approved for acute RS but not CRS, he pointed out that culture-directed therapy allows clinicians to target the bacteria that should be obliterated. This is more efficient than using broad-spectrum agents empirically. “Narrow-spectrum agents have a better side-effect profile, better compliance rates, and create less resistance, although this latter point is debatable,” he remarked. “Broad-spectrum agents kill good bacteria (normal flora), giving pathogenic bacteria the opportunity to grow back when these agents are used.”

Dr. Bhattacharyya advocates administering one round of empirical antibiotics to CRS patients who have not had surgery. If that fails, he recommends performing a culture and then prescribing the proper antibiotics. For patients with a long history of CRS and antibiotic use, or for those who have had surgery, he suggests performing the culture immediately and then prescribing appropriate antibiotics. He reiterated that “in general, antibiotic resistance is increasing. But this is not destiny for CRS patients,” especially if culture-directed treatment is initiated. Dr. Bhattacharyya commented that future studies should focus on identifying subsets of patients with resistance, not necessarily from antibiotic use but from the patients’ own microenvironments.

—Tamara Gibb

Reference
1. Bhattacharyya N, Kepnes LJ. The risk of development of antimicrobial resistance in individual patients with chronic rhinosinusitis. Arch Otolaryngol Head Neck Surg. 2004;130:1201-1204.

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