Abstract

Yuanchun Huang, Qing Peng*, Fen Yao, Yuanshu Qian, Yingmu Cai, Xiaoyang Jiao and Dexing Hua

This study is the first to report on the resistant phenotypes and genotypes of Enterococcus faecium clinical isolates in Shantou, China. A total of 39 E. faecium clinical isolates were collected from January 2004 to January 2006 and analyzed for their resistance to 10 antibiotics and for genes coding for resistance to the associated antibiotics. E. faecium isolates were resistant to 5 or more antibiotics, and most showed high minimal inhibitory concentrations to many antibiotics as well. Resistance to erythromycin, ciprofloxacin, levofloxacin, and penicillin was 100.0, 100.0, 97.4, and 92.3%, respectively. The mean resistance to ampicillin, chloramphenicol, tetracycline, and high levels of gentamicin was 80% or greater for each. Neither -lactamaseproducing nor vancomycin-resistant isolates were found. Genes such as aph(3 )- ,ermB, aac(6 )/aph2 , ant(6)- ,gyrA, TetM, ParC, and pbp5 coding for resistance to the associated antibiotics were present at 79.5, 71.8, 92.3, 71.8, 100.0, 38.5, 23.1 and 69.2% respectively. E. faecium isolates showing multidrug resistance (MDR) were prevalent in Shantou. A total of 32 strains carried at least 5 resistance genes. The gene profile of E. faecium isolates (ermB/aac(6 )/aph2 /aph(3 )- /ant(6)- /gyrA/Pbp5) indicated that most of the strains carried MDR in different regions. The high occurrence of MDR suggested maintenance of selective pressure by use of different antibiotics. A rapid increase in antibiotic resistance is the result of incorrect antibiotics.