Antimicrobial susceptibility and genetic characteristics of <it>Neisseria gonorrhoeae</it> isolates from Vietnam, 2011

<p>Abstract</p> <p>Background</p> <p>Antimicrobial resistance (AMR) in <it>Neisseria gonorrhoeae</it> is a major public health concern worldwide. In Vietnam, knowledge regarding <it>N. gonorrhoeae</it> prevalence and AMR is limited, and data conc...

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Main Authors: Olsen Birgitta, Lan Pham Thi, Golparian Daniel, Johansson Emma, Khang Tran Hau, Unemo Magnus
Format: Article
Language:English
Published: BMC 2013-01-01
Series:BMC Infectious Diseases
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Online Access:http://www.biomedcentral.com/1471-2334/13/40
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Summary:<p>Abstract</p> <p>Background</p> <p>Antimicrobial resistance (AMR) in <it>Neisseria gonorrhoeae</it> is a major public health concern worldwide. In Vietnam, knowledge regarding <it>N. gonorrhoeae</it> prevalence and AMR is limited, and data concerning genetic characteristics of <it>N. gonorrhoeae</it> is totally lacking. Herein, we investigated the phenotypic AMR (previous, current and possible future treatment options), genetic resistance determinants for extended-spectrum cephalosporins (ESCs), and genotypic distribution of <it>N. gonorrhoeae</it> isolated in 2011 in Hanoi, Vietnam.</p> <p>Methods</p> <p><it>N. gonorrhoeae</it> isolates from Hanoi, Vietnam isolated in 2011 (n = 108) were examined using antibiograms (Etest for 10 antimicrobials), <it>Neisseria gonorrhoeae</it> multi-antigen sequence typing (NG-MAST), and sequencing of ESC resistance determinants (<it>penA</it>, <it>mtrR</it> and <it>penB</it>).</p> <p>Results</p> <p>The levels of in vitro resistance were as follows: ciprofloxacin 98%, tetracycline 82%, penicillin G 48%, azithromycin 11%, ceftriaxone 5%, cefixime 1%, and spectinomycin 0%. The MICs of gentamicin (0.023-6 mg/L), ertapenem (0.002-0.125 mg/L) and solithromycin (<0.016-0.25 mg/L) were relatively low. No <it>penA</it> mosaic alleles were found, however, 78% of the isolates contained an alteration of amino acid A501 (A501V (44%) and A501T (34%)) in the encoded penicillin-binding protein 2. A single nucleotide (A) deletion in the inverted repeat of the promoter region of the <it>mtrR</it> gene and amino acid alterations in MtrR was observed in 91% and 94% of the isolates, respectively. <it>penB</it> resistance determinants were detected in 87% of the isolates. Seventy-five different NG-MAST STs were identified, of which 59 STs have not been previously described.</p> <p>Conclusions</p> <p>In Vietnam, the highly diversified gonococcal population displayed high in vitro resistance to antimicrobials previously recommended for gonorrhoea treatment (with exception of spectinomycin), but resistance also to the currently recommended ESCs were found. Nevertheless, the MICs of three potential future treatment options were low. It is essential to strengthen the diagnostics, case reporting, and epidemiologic surveillance of gonorrhoea in Vietnam. Furthermore, the surveillance of gonococcal AMR and gonorrhoea treatment failures is imperative to reinforce. Research regarding novel antimicrobial treatment strategies (e.g., combination therapy) and new antimicrobials is crucial for future treatment of gonorrhoea.</p>
ISSN:1471-2334