New features in drug resistance of Haemophilus inlfuenzae isolated from children with infection diseases in Suzhou during 2011-2012 / 临床儿科杂志

ABSTRACT

Objectives To investigate the changes and features of drug resistance in Haemophilus inlfuenzae (Hi) isolated from children with infection diseases in Suzhou. Methods One thousand two hundred and twenty-two Hi strains isolated from clinical specimens were collected from January 2011 to June 2012. Antimicrobial susceptibility was tested by Kirby-Bauer me-thod, andβ-lactamase was analyzed by chromogenic nitroceifn method. Then strains were divided into four groups according to their speciifc resistance patterns①β-lactamase positive strains (except for cefuroxime-resistant strains),②β-lactamase negative ampicillin-resistant (BLNAR) strains,③cefuroxime-resistant strains, and④other resistant strains. Results The resistance of iso-lated Hi from children in Suzhou area to ampicillin, co-trimoxazole, cefaclor, tetracycline, chloramphenicol, azithromycin, cefu-roxime, ampicillin/sulbactam was 32.7%, 76.7%, 27.4%, 14.3%, 10.2%, 8.4%, 6.9%and 4.3%, respectively, and the detection rate in four groups was 29.0%, 2.6%, 6.9%, 41.2%, respectively. Multi-resistant strains were mainly distributed in Group①and Group②, accounting for 67.5%and 81.3%of each group. Azithromycin, tetracycline and chloramphenicol showed high antimicrobial activity against BLNAR and cefuroxime-resistant Hi strains. The positive rate of resistance toβ-lactamase was 30.8%. The rates of resistance to cefuroxime, cefaclor, ampicillin/sulbactam and cotrimoxazole inβ-lactamase-positive ampicillin-resistant strains are signiifcantly different from those inβ-lactamase-negative ampicillin-resistant strains. Conclusions The resistance feature of Hi isolated from children in Suzhou shows signiifcant changes, including new appearance of cefuroxime-resistant strain, a rapid increase in resistance to azithromycin, and a large proportion of multidrug-resistant strains. The rapid increase in BLNAR and the emergence of cefuroxime-resistant strains have become the new resistance pattern of Hi in this area.