Introduction: The emergence of multi-drug-resistant Gram-negative bacteria (GNB) is a concern in China and globally. This study investigated antimicrobial resistance traits and resistance determinant detection in GNB isolates from paediatric patients in China.
Methods: In the present study, a total of 170 isolates of GNB including the most prevalent Escherichia coli, Klebsiella pneumoniae  and Acinetobacter baumannii  were collected from Shenzhen Children’s Hospital, China. ESBLs production was confirmed by using the combination disc diffusion method, and carbapenemase production was confirmed by using a carbapenem inactivation method followed by antimicrobial susceptibility. In addition, β-lactamase-encoding genes and co-existence of plasmid-borne colistin resistance mcr-1  gene were determined by PCR and sequencing.
Results: Overall, 170 etiological agents (GNB) were recovered from 158 paediatric patients. The most prevalent species was E. coli  40% (n=68), followed by K. pneumoniae  17.64% (n=30), and Enterobacter cloacae  14.11% (n=24). Of 170 GNB, 71.76% (n=122) were multi-drug-resistant, 12.35% (n=21) extreme-drug resistant, and 7.64% (n=13) single-drug-resistant, while 8.23% (n=14) were sensitive to all of the studied antibiotics. The prevalence of ESBLs and carbapenemase producers were 60% and 17%, respectively. bla _CTX-M was the most prevalent resistance gene (59.42%), followed by bla _TEM (41.17%), bla _SHV (34.270%), bla _KPC (34.11%), bla _OXA-48 (18.82%) and bla _NDM-1 (17.64%).
Conclusion: The present study provides insights into the linkage between the resistance patterns of GNB to commonly used antibiotics and their uses in China. The findings are useful for understanding the genetics of resistance traits and difficulty in tackling of GNB in paediatric patients.
Keywords: Gram-negative bacteria, antimicrobial susceptibility, ESBLs, carbapenemase, molecular characterization