Contemporary trends in microbiology and antibiotic resistance in otolaryngology.
OBJECTIVE
to determine current microbiologic yields and characterize antibiotic resistance patterns for organisms cultured from head and neck infections.


METHODS
results of out-patient cultures submitted from an academic otolaryngology practice over the period 1994-1998 were reviewed. A database was constructed, and culture results were analyzed for sites of infection, organism recovery rate, infecting microbiological agent, antibiotic resistance patterns, and 5-year trends. chi(2) analysis was used to determine associations between site of infection, infecting agent and antibiotic resistance over the years of the study.


RESULTS
a total of 986 aerobic cultures were reviewed. The most common sites cultured were the nose/paranasal sinuses (469), throat (377), and ear (23). In 465 (47.2%) cultures, normal flora or no growth occurred. Of the throat culture subset, 69.7% were negative, whereas 69.1% of sinonasal cultures recovered organisms. Gram positive cocci were the most commonly recovered organism type (30.9%), followed by Gram negative rods (GNR, 17.2%). These rates remained relatively constant over the years of the study. GNR were found in 39.1 and 25.2% of ear and sinus cultures, respectively. Antibiotic sensitivities were conducted on 257 specimens (49.3% of positive cultures). The average number of antibiotic resistances per bacteria remained stable at approximately 1.59 over the years (P=0.086, analysis of variance (ANOVA)). Antibiotic resistance rates increased for clindamycin, cefazolin, and erythromycin over the years of the study (P<0.05, chi(2)). Ciprofloxacin, gentamicin and trimethoprim-sulfamethoxazole resistance rates did not increase over the years of the study. Vancomycin resistance did not occur.


CONCLUSIONS
as a significant proportion of head and neck cultures will be negative, their utility should be re-examined. GNR infections are more common in the head and neck than earlier thought. There is a trend towards increasing antibiotic resistance in head and neck infections, urging careful and appropriate use of antibiotics.
Bhattacharyya
Neil
N
Division of Otolaryngology, Brigham and Women's Hospital, Harvard Medical School, 333 Longwood Avenue, Boston, MA 02115, USA. neiloy@massmed.org
Shapiro
Jo
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002648:Child; D002675:Child, Preschool; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008829:Microbiology / Q000639:trends*; D008875:Middle Aged; D010036:Otolaryngology / Q000639:trends*; D010254:Paranasal Sinus Diseases / Q000188:drug therapy* / Q000382:microbiology*
D000900:Anti-Bacterial Agents