Distribution and drug resistance of bacterial pathogens isolated from peritonsillar abscess during 2010-2014 in Wenzhou

Abstract

Objective To investigate the distribution and drug resistance of bacterial pathogens isolated from peritonsillar abscess. Methods Data on bacterial pathogens isolated from peritonsillar abscess in Wenzhou Central Hospital from January 2010 to December 2014 were retrospectively analyzed.Strains were identified with Vitek 32 identification system and the drug susceptibility test was performed with K-B method. Chi-square test for linear trend was performed to reveal the changes of distribution and drug resistance of the strains. Results A total of 2 864 bacterial strains were isolated in five years, in which 1 786 strains were Gram-negative bacilli (62.4%), and 1 078 (37.6%) strains were Gram-positive cocci. The positive rate of Gram-negative bacilli was on the rise during year 2010-2014 (χ2=84.74, P<0.01), and the top three Gram-negative bacilli were Pseudomonas aeruginosa, Acinetobacter baumannii and Haemophilus influenzae, which accounted for 72.5% (1 295/1 786) of the total Gram-negative strains, and the positive rates of first two bacilli were on the rise (χ2=83.75 and 24.74, P<0.01). Gram-positive cocci were mainly Staphylococcus aureus and Hemolytic streptococcus, which accounted for 83.2% (897/1 078) of the total Gram-positive strains. Resistance rates of Pseudomonas aeruginosa to ceftazidime, cefoperazone, piperacillin/tazobactam were on the rise (χ2=16.17, 13.48 and 11.44, P<0.05), while resistance rates to gentamicin and amikacin were on the decline (χ2=16.54 and 16.63, P<0.05). Resistance rates of Acinetobacter baumannii to ceftazidime, cefoperazone/sulbactam and piperacillin/tazobactam were on the rise (χ2=12.52, 10.85 and 14.14, P<0.05). Resistance rates of Haemophilus influenzae to ampicillin were on the rise (χ2=10.21, P<0.05), and the positive rate of β-lactamase producing strains was also on the rise (χ2=10.38, P<0.05). Resistance rates of Staphylococcus aureus to cefazolin and methicillin were on the rise (χ2=15.44 and 12.53, P<0.05), but no vancomycin resistant strain was found. Hemolytic streptococcus were sensitive to all commonly used antibiotics. Conclusions Peritonsillar abscess in Wenzhou Central Hospital is mainly induced by Gram-negative bacilli infection. Pseudomonas aeruginosa, Acinetobacter baumannii and Staphylococcus aureus are the top three bacterial pathogens, and are highly resistant to most antibiotics. Key words: Peritonsillar abscess; Gram-negative bacteria; Gram-positive cocci; Bacterial infection; Drug resistence; Microbial sensitivity tests