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Emergence and Spread of Neisseria gonorrhoeae Isolates With Decreased Susceptibility to Extended-Spectrum Cephalosporins in Argentina, 2009 to 2013

Gianecini, Ricardo MSc*; Romero, Maria de las Mercedes MSc*; Oviedo, Claudia MSc*; Vacchino, Martin MSc*; Galarza, Patricia MSc, MPH*; Gonococcal Antimicrobial Susceptibility Surveillance Programme-Argentina (GASSP-AR) Working Group

Sexually Transmitted Diseases: June 2017 - Volume 44 - Issue 6 - p 351–355
doi: 10.1097/OLQ.0000000000000603
Original Studies

Background: The emergence of Neisseria gonorrhoeae strains with decreased susceptibility to cephalosporins represents a major concern globally. The aim of this study was to examine the phenotypic and molecular characteristics of N. gonorrhoeae isolates with decreased susceptibility to ceftriaxone and cefixime in Argentina.

Methods: A total of 1987 isolates were collected during 2009 and 2013. The susceptibility to penicillin G, tetracycline, ciprofloxacin, cefixime, ceftriaxone, and azithromycin was determined using the agar dilution method. The major extended-spectrum cephalosporin resistance determinants (penA, mtrR, and porB1b) were sequenced in 42 N. gonorrhoeae isolates that showed decreased susceptibility to ceftriaxone (minimum inhibitory concentration [MIC], 0.06–0.125 mg/L) and cefixime (MIC, 0.125–0.25 mg/L). Genotyping by N. gonorrhoeae multiantigen sequence typing (NG-MAST) was performed.

Results: Between 2009 and 2013, there was a shift in the modal MICs for ceftriaxone. Among the 42 isolates exhibiting decreased susceptibility to ceftriaxone and cefixime, 95.2% were resistant to penicillin G, 95.2% to tetracycline, 97.6% to ciprofloxacin, and 33.3% to azithromycin. Thirty-five (83.3%) of the 42 isolates had a mosaic penA allele XXXIV, which has been previously associated with resistance to ceftriaxone and cefixime as well as treatment failures. The isolates that contained the mosaic penicillin-binding protein 2 (PBP2) XXXIV were associated with NG-MAST ST1407 or closely related genotypes.

Conclusions: In Argentina, N. gonorrhoeae isolates with decreased susceptibility to cefixime and ceftriaxone have now emerged, mostly due to the introduction of the internationally spread multidrug-resistant NG-MAST ST1407.

A study to describe the phenotypic and genetic characteristics of Neisseria gonorrhoeae isolates with decreased susceptibility to extended spectrum cephalosporins between 2009 and 2013 in Argentina.

From the *Servicio de Enfermedades de Transmisión Sexual, Instituto Nacional de Enfermedades Infecciosas (INEI)-ANLIS “Dr. Carlos G. Malbrán”, Ciudad Autónoma de Buenos Aires, Argentina

ACKNOWLEDGEMENTS: The authors are grateful to the Pan American Health Organization (PAHO/WHO) for providing technical assistance through the Latin American Quality Control Program of N. gonorrhoeae. The authors also thank the Genomics and Bioinformatics Platform from the National Institute of Infectious Diseases (INEI)-ANLIS “Dr. Carlos G. Malbrán” for their valuable contribution. Additionally, the authors thank Melisa Soledad Gonzalez and Antonia Rojas for their technical assistance in this study.

GASSP-AR Working Group: Ciudad Autónoma de Buenos Aires: L Caniggia, S Montibello, L Buscemi, J Smayevski, M Turco, C Garbaz, M Morales, C Alfonso, M Montoto, M Marcato, A Casimiro, M Cervetto, M Giovanakis, N Apestey; Buenos Aires: N Casanova, S Di Bartolomeo, M Machaín, M Garrone, R Padlog, V Vilches, M Sparo, A Retes, A Tognieri, M Almuzara, M Rizzo, V Cagnoni; Córdoba: S Gonzalez, A Littvik; Santa Fe: S Morano, E Mendez, J Valles, A Nepote; Chaco: L Piccoli, H Solís, A Guillen; Salta: S Amador, C Guantay, C Arias; Neuquén: M Núñez; Rio Negro: G Stafforini, N Blazquez, M Roncallo, M Alvarez, D Durany; Chubut: M Ricciardi, M Flores; La Pampa: A Pereyra, N Scarone; Mendoza: S Bontti, F Ampuero, C Bandoni; Santa Cruz: W Krause; Formosa: N Pereyra, M Vivaldo; San Luis: D León; Entre Ríos: N Yoya, F Salamone; Tucumán: C Estrella, C Teich, L Grellet; Jujuy: M Mernes; San Juan: M Albarracín, P Ranea, R Reinoso; Santiago del Estero: M Maza de Alegre; Tierra del Fuego: G Castro, M Vargas; La Rioja: M Romanazzi; Corrientes: S Ferrero; Misiones: G Bello Velázquez, S Roginski; Catamarca: V Gonzalez.

This study was supported by the National Administration of Laboratories and Health Institutes (ANLIS) “Dr. Carlos G. Malbrán”-Ministry of Health, Argentina, and by grant from the Alberto J. Roemmers Foundation.

Conflict of Interest and: None declared.

Correspondence: Patricia Galarza, MSc, MPH, Velez Sarsfield 563, C1282AFF, Ciudad Autónoma de Buenos Aires (CABA), Argentina. E-mail:

Received for publication November 11, 2016, and accepted January 29, 2017.

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