Qingqing Xia

Molecular Characteristics of Salmonella Genomic Island 1 in Proteus mirabilis Isolates from Poultry Farms in China

ABSTRACT Six out of the 64 studied Proteus mirabilis isolates from 11 poultry farms in China contained Salmonella genomic island 1 (SGI1). PCR mapping showed that the complete nucleotide sequences of SGI1s ranged from 33.2 to 42.5 kb. Three novel variants, SGI1-W, SGI1-X, and SGI1-Y, have been characterized. Resistance genes lnuF, dfrA25, and qnrB2 were identified in SGI1 for the first time.

Prevalence of 16S rRNA methylase conferring high-level aminoglycoside resistance in Escherichia coli in China

entamicin, ciprofloxacin and/or third-generation cephalosporins ncreased from 7.8% at baseline to 49% after international travel. n 18% of individuals, prolonged colonisation for >6 months ccurred [5]. These individuals may act as reservoirs for infecion within the community or as sources of outbreak when hey are hospitalised [2,3,5]. In many countries there are no ational guidelines for admission screening of individuals who ave a history of medical treatment abroad. Second, the optimal reatment for invasive carbapenem-resistant Enterobacteriaceae nfections is uncertain and is complicated by the frequent occurence of co-resistance to many other antibiotics. The agents that re potentially active against carbapenem-resistant Enterobactericeae are colistin, tigecycline, fosfomycin and isepamicin. In solid rgan and bone marrow transplant recipients, infections by these rganisms represent a tremendous threat. In response to these hallenges, hospitals in Hong Kong have recently introduced active creening for carbapenem-resistant Enterobacteriaceae carriage t hospital admission. Under the arrangement, all newly admited patients with history of hospitalisation, surgery or dialysis n an overseas institution in the previous 12 months would be creened. Funding: This work was supported by research grants from the esearch Fund for the Control of Infectious Diseases (RFCID) of the ealth, Welfare and Food Bureau of the Hong Kong SAR Governent. Competing interests: None declared. Ethical approval: Not required.

Dynamics of quinolone resistance in fecal Escherichia coli of finishing pigs after ciprofloxacin administration.

ABSTRACT Escherichia coli resistance to quinolones has now become a serious issue in large-scale pig farms of China. It is necessary to study the dynamics of quinolone resistance in fecal Escherichia coli of pigs after antimicrobial administration. Here, we present the hypothesis that the emergence of resistance in pigs requires drug accumulation for 7 days or more. To test this hypothesis, 26 pigs (90 days old, about 30 kg) not fed any antimicrobial after weaning were selected and divided into 2 equal groups: the experimental (EP) group and control (CP) group. Pigs in the EP group were orally treated daily with 5 mg ciprofloxacin/kg of body weight for 30 days, and pigs in the CP group were fed a normal diet. Fresh feces were collected at 16 time points from day 0 to day 61. At each time point, ten E. coli clones were tested for susceptibility to quinolones and mutations of gyrA and parC. The results showed that the minimal inhibitory concentration (MIC) for ciprofloxacin increased 16-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin administration for 3 days and decreased 256-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin withdrawal for 26 days. GyrA (S83L, D87N/ D87Y) and parC (S80I) substitutions were observed in all quinolone-resistant E. coli (QREC) clones with an MIC ≥8 µg/ml. This study provides scientific theoretical guidance for the rational use of antimicrobials and the control of bacterial resistance.