Antibiotic resistant gene discovered

A new antibiotic resistant gene discovered by a leading Cardiff University scientist has been found in UK patients for the first time.Professor Tim Walsh, School of Medicine, first identified the NDM-1 gene in Klebsiella pneumoniae and Escherichia coli bacteria taken from a Swedish patient admitted to hospital in India in 2009.

The new NDM-1-producing bacteria are resistant to many antibiotics including carbapenems, a group of antibiotics generally reserved for use in emergencies and the treatment of infections caused by multi-resistant bacteria.

In a new major research study, published in The Lancet Infectious Diseases, Professor Walsh investigated how common the NDM-1 producing antibiotic resistant bacteria are in Bangladesh, India, and Pakistan and the importation of these bacteria into the UK via patients returning from these countries.

Professor Walsh from the School of Medicine’s Department of Medical Microbiology said: "A new gene NDM-1 that enables bacteria to be highly resistant to almost all antibiotics is widespread in Enterobacteriaceae taken from patients in India and Pakistan, and has also been found in UK patients who travelled to India for elective surgery."

The study collected bacteria samples from patients presenting with various hospital and community-associated infections in Chennai and Haryana in India, and from patients referred to the UK’s national reference laboratory between 2007 and 2009.

Samples were tested for antibiotic susceptibility and the presence of the NDM-1 gene using polymerase chain reaction (PCR) and sequencing.

They identified 44 (1.5%) NDM-1-positive bacteria in Chennai, 26 (8%) in Haryana, 37 in the UK, and 73 in other sites in Bangladesh, India, and Pakistan. NDM-1 was mostly found in E. coli (36), the most common cause of community-associated urinary tract infections, and K. pneumoniae (111).

The NDM-1-producing bacteria were highly resistant to all antibiotics except tigecycline and colistin. In some cases, isolates were resistant to all antibiotics.

The authors say that the emergence of NDM-1 positive bacteria is potentially a serious global public health problem as there are few new anti-Gram-negative antibiotics in development and none that are effective against NDM-1.

Professor Walsh added: "The rapid emergence of these multi-drug resistant NDM-1 producing bacteria and their potential worldwide spread could herald a period in which antibiotics become redundant and demands very close international monitoring and surveillance."

(Source: Cardiff University: Lancet Infectious Diseases)