Dissemination of NDM-1
2012; Elsevier BV; Volume: 12; Issue: 2 Linguagem: Inglês
10.1016/s1473-3099(11)70333-4
ISSN1474-4457
AutoresBadrul Hasan, Peter Drobni, Mirva Drobni, Munirul Alam, Björn Olsén,
Tópico(s)Healthcare and Environmental Waste Management
ResumoIn The Lancet Infectious Diseases, Karthikeyan Kumarasamy and colleagues1Kumarasamy KK Toleman MA Walsh TR et al.Emergence of a new antibiotic resistance mechanism in India, Pakistan, and the UK: a molecular, biological, and epidemiological study.Lancet Infect Dis. 2010; 10: 597-602Summary Full Text Full Text PDF PubMed Scopus (2182) Google Scholar reported that blaNDM-1-containing bacteria was isolated from a few patients in India, Pakistan, and Bangladesh. Subsequently, Timothy Walsh and colleagues2Walsh TR Weeks J Livermore DM Toleman MA Dissemination of NDM-1 positive bacteria in the New Delhi environment and its implications for human health: an environmental point prevalence study.Lancet Infect Dis. 2011; 11: 355-362Summary Full Text Full Text PDF PubMed Scopus (900) Google Scholar identified blaNDM-1-carrying bacterial species from the Enterobacteriaceae, Aeromonadaceae, Vibrionaceae, and Pseudomonadaceae, and some other non-fermenters, in New Delhi water samples. The emergence and rapid environmental dissemination of NDM-1 in a densely populated country like India is a very worrying scenario. We believe that poor management of the hospital environment and medical waste could be one of many routes of environmental dissemination of pathogens, especially in south Asian countries. For example, in Bangladesh and India, medical facilities rarely have provision for internal waste treatment, and solid hospital waste is often disposed of without proper care on hospital premises3Hassan MM Ahmed SA Rahman KA Biswas TK Pattern of medical waste management: existing scenario in Dhaka City, Bangladesh.BMC Public Health. 2008; 8: 36Crossref PubMed Scopus (80) Google Scholar and liquid waste from hospitals flows with sewage into open ditches and urban river systems. Wild animals, and birds in particular, can carry and spread multidrug-resistant bacteria and CTX-M-carrying bacteria.4Bonnedahl J Drobni M Gauthier-Clerc M et al.Dissemination of Escherichia coli with CTX-M type ESBL between human and yellow-legged gulls in south of France.PLoS One. 2009; 4: e5958Crossref PubMed Scopus (168) Google Scholar However, the prevalence of infection in birds living close to people is probably related to the extent of antibiotic resistance in the environment.4Bonnedahl J Drobni M Gauthier-Clerc M et al.Dissemination of Escherichia coli with CTX-M type ESBL between human and yellow-legged gulls in south of France.PLoS One. 2009; 4: e5958Crossref PubMed Scopus (168) Google Scholar, 5Literák I Vanko R Dolejská M Cízek A Karpísková R Antibiotic resistant Escherichia coli and Salmonella in Russian rooks (Corvus frugilegus) wintering in the Czech Republic.Lett Appl Microbiol. 2007; 45: 616-621Crossref PubMed Scopus (44) Google Scholar During a research trip to Bangladesh in 2010, we analysed 150 faecal samples from gulls along the coastline and 238 faecal samples from crows in the grounds of Rajshahi Medical College Hospital and Chittagong Medical College Hospital to detect blaNDM-1 expression. We enriched every sample with brain–heart infusion broth supplemented with vancomycin (16 mg/L) for 18 h at 37°C, followed by inoculation and overnight culture at 37°C on chromID extended-spectrum β-lactamase (ESBL) plates. We isolated bacterial colonies and verified the identity of species by biochemical testing and with API 20E biochemical strips. We used the cefpodoxime and cefpodoxime plus clavulanic acid double disc test to measure ESBL production. We isolated ESBL-producing Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Citrobacter freundii, and Raoultella terrigena from the bird faeces. More than 59% of crow faeces and 27% of gull faeces were ESBL-positive phenotypically. To detect blaNDM-1 in these samples, we developed a quantitative PCR with the K pneumoniae plasmid pKpANDM-1 sequence6Yong D Toleman MA Giske CG et al.Characterization of a new metallo-beta-lactamase gene, bla(NDM-1), and a novel erythromycin esterase gene carried on a unique genetic structure in Klebsiella pneumoniae sequence type 14 from India.Antimicrob Agents Chemother. 2009; 53: 5046-5054Crossref PubMed Scopus (1789) Google Scholar and Primer3 software.7Rozen S Skaletsky H Primer3 on the WWW for general users and for biologist programmers.in: Misener S Krawetz SA Bioinformatics methods and protocols: methods in molecular biology. Humana Press, Totowa, NJ2000: 365-386Google Scholar We designed a forward primer (NDM1_123F: 5′-CGG CGT AGT GCT CAG TGT C-3′) and reverse primer (NDM1_281R: 5′-GCC CGC TCA AGG TAT TTT AC-3′) and used iQ SYBR Green Supermix. All isolates were negative for blaNDM-1. We believe that birds that live close to people might be transmitting ESBL-producing bacteria from hospital to community. Bangladesh shares borders with India, and many people from both countries cross them for trade, medical treatment, and other reasons. The presence of NDM-1 in the environment is a sign of wide dissemination in India, and Bangladesh will probably be the next country to be affected by NDM-1-carrying bacteria. Although we did not detect NDM-1 in Bangladeshi bird faeces, the presence of NDM-1 in Bangladesh cannot be ruled out. Environmental reservoirs of NDM-1-carrying bacterial strains in Bangladesh now need to be identified to stop further spread of these dangerous pathogens. We declare that we have no competing interests. We thank C G Giske for providing the control strain of NDM-1-carrying Klebsiella pneumonia 05-506; Ahasanul Alam of Rajshahi Medical College; Laboni Akter of Chittagong Medical College, Bangladesh; Uppsala University, Sweden; and International Centre for Diarrhoeal Disease Research, Bangladesh, for logistic support during sample collection. Our study was financially supported by Uppsala University, the Swedish Research Council Formas, and Karin Korsner's foundation. Dissemination of NDM-1 – Authors' replyWe thank the three correspondents for their responses to our Article.1 Badrul Hasan and colleagues identified extended-spectrum β-lactamases (ESBLs) in faecal samples from wild birds; although the samples were negative for blaNDM-1, the gene might have been missed because the forward NDM-1 primer at position 123 is in fact a reverse primer at position 691–673 and the reverse primer is a forward primer at position 533–549, resulting in a PCR product of only 150 base pairs. 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