Researchers report hospital outbreak of mcr-1-producing K. pneumoniae in China
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Researchers reported a hospital outbreak of mcr-1-producing Klebsiella pneumoniae among pediatric leukemia patients in China.
In a letter published in The Lancet Infectious Diseases, Guo-Bao Tian, PhD, of the Zhongshan School of Medicine at Sun Yat-sen University, and colleagues said the plasmid-mediated colistin resistance gene was found in six clinical isolates — five K. pneumoniae and one Escherichia coli — taken between December 2015 and January 2016 from six patients with pneumonia in a pediatric leukemia ward in Guangzhou, China, including two who died from their infections.
In 2015, Tian and colleagues were the first researchers to document mcr-1 after discovering it while conducting a routine antimicrobial resistance surveillance project in China. Since its discovery, mcr-1 has been found in food, food animals and humans, including patients in the United States.
The gene’s emergence has raised alarms because of its ability to transmit resistance to colistin — considered a last-resort antibiotic — between bacteria. China recently banned the use of colistin as a growth stimulator in agriculture but approved its use to treat patients for the first time.
Recently, Tian and colleagues reported in January that they had located mcr-1 in a variety of strains of bacteria in China and that it was more likely to be found in male patients who had been on antibiotics before being hospitalized.
According to Tian and colleagues, all six isolates taken from the pediatric patients with leukemia in Guangzhou were resistant to colistin, polymyxin B, cefotaxime and gentamicin, whereas the K. pneumoniae isolates were also resistant to ceftazidime, cefepime, amikacin, fosfomycin and ciprofloxacin. The researchers reported that the patients were treated with different combinations of vancomycin, imipenem, lincomycin, cefotaxime and caspofungin acetate.
Sequencing showed that all five K. pneumoniae isolates were from ST11, whereas the E. coli strain belonged to ST156. Testing showed the K. pneumoniae isolates were all clonally related.
“In conclusion,” Tian and colleagues wrote, “we identified a hospital outbreak of an mcr-1-producing K. pneumoniae ST11 strain among children with acute leukemia. Our finding suggests that mcr-1 can spread in the hospital environment in the absence of colistin use.” – by Gerard Gallagher
Disclosure: The researchers report no relevant financial disclosures.