1, JN119854.1, JN108899.1, HQ880271.1, GU944731.1, GU120473.1, JQ780837.1 and HQ880255.1) and 5 clinical strains (Table 2, including 3 strains of Klebsiella pneumoniae and 2 strains of Escherichia coli) were selected as positive controls, Escherichia

coli ATCC#25922 and Escherichia coli J53 were used as negative controls. In the initial experiment, the distributions of aminoglycoside resistance genes among those controls strains were confirmed by conventional PCR with the specific primers listed in Table 3. Fifty six clinical isolates of Enterobacteriaceae were used to evaluate the utility of GeXP assay. All the clinical samples were taken as part of standard patient care from the inpatients at Guangzhou First Municipal People’s Hospital from January learn more 2008 to December 2009. This protocol was approved by the Committee on the Use of Human Subjects in Research at Guangzhou First Municipal People’s Hospital, an affiliated hospital of Guangzhou Medical College. All the informed consents from the inpatients themselves or their guardians were obtained. In initial experiments, the identification of the clinical isolates and the minimum inhibitory concentrations (MICs) of antibiotics www.selleckchem.com/products/Adrucil(Fluorouracil).html were confirmed

by the VITEK® 2 system (bioMérieux, France) (Additional file 1). Forty eight of the 56 isolates (including 30 strains of Klebsiella pneumoniae and 18 strains of Escherichia coli) presented resistance to gentamicin (MIC≥16μg/mL), tobramycin (MIC≥16μg/mL) and/or amikacin (MIC≥64μg/mL), the other 8 isolates (including 5 strains of Klebsiella pneumoniae Tangeritin and 3 strains of Escherichia coli) were susceptible to gentamicin (MIC≤4μg/mL), tobramycin (MIC≤4μg/mL) and amikacin (MIC≤16μg/mL) according to the standards of Clinical and Laboratory Standards Institute (CLSI 2012). Table 1 Distribution of aminoglycoside resistance genes in 8

reference strains Strains No. Reference strains Presence of aminoglycoside resistance genes GenBank accession no. NF512663 Escherichia coli aac(6’)-Ib [aacA4]* JN108884.1 NF802568 Escherichia coli ant(3”)-II [aadA2] * JN119854.1 NF811738 Klebsiella pneumoniae aac(6’)-Ib [aacA4] *& ant(3”)-I [aadA1] * JN108899.1 NF707346 Klebsiella pneumoniae ant(2”)-I [aadB] *& ant(3”)-I [aadA1] * HQ880271.1 NF802824 Klebsiella pneumoniae acc(6’)-II GU944731.1 NF811834 Klebsiella pneumoniae aadA5 GU120473.1 NF141160 Acinetobacter baumannii aac(3’)-I [aacC1] * & ant(3”)-I [aadA1] * JQ780837.1 NF910192 Pseudomonas putida aac(6’)-II & ant(2”)-I [aadB] * HQ880255.1 * Synonyms in the bracket. Table 2 Distribution of aminoglycoside resistance genes in 5 positive control isolates Strains No.