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Brazilian Journal of Microbiology

Print version ISSN 1517-8382On-line version ISSN 1678-4405

Braz. J. Microbiol. vol.38 no.2 São Paulo Apr./June 2007 



Emergence of fluoroquinolone–resistant neisseria gonorrhoeae in São Paulo, Brazil


Emergência de Neisseria gonorrhoeae resistente à fluoroquinolona em São Paulo, Brasil



Walter Belda JuniorI; Paulo Eduardo Neves Ferreira VelhoII,*; Marcelo ArnoneIII; Luis Jorge FagundesIV

I,IIIDepartamento de Dermatologia, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
IIDepartamento de Clínica Médica, Faculdade de Ciências Médicas, Universidade Estadual de Campinas, Campinas, SP, Brasil
IVFaculdade de Saúde Pública, Universidade de São Paulo, São Paulo, SP, Brasil




Continued monitoring of antimicrobial resistance patterns is essential in order for Sexually Transmitted Diseases (STD) treatment to be effective. Gonococci isolates from 65 patients in São Paulo were submitted to susceptibility testing, and a decreased susceptibility or resistance to ciprofloxacin was observed in 8.7% of these patients, indicating that Neisseria gonorrhoeae fluoroquinolone resistance is emerging in Brazil.

Key–words: anti–bacterial agents, ciprofloxacin, drug resistance, Neisseria gonorrhoeae


O monitoramento contínuo de resistência antimicrobiana é essencial para a efetividade do tratamento das Doenças Sexualmente Transmissíveis (DST). Gonococosisolados de 65 pacientes de São Paulo foram submetidos a teste de susceptibilidade verificando–se que 8,7% apresentavam susceptibilidade diminuída ou resistência ao ciprofloxacino, o que indica que a resistência da Neisseria gonorrhoeae às fluoroquinolonas é emergente no Brasil.

Palavras–chave: agentes antibacterianos, ciprofloxacino, resistência a drogas, Neisseria gonorrhoeae



Despite a sharp decline in the incidence of gonococci infections in developed countries during the last decade, gonorrhea remains one of the most common sexually transmitted infections in developing countries and is a global health problem (9). This emerging resistance of Neisseria gonorrhoeae to antimicrobial agents, resulting from both wide dissemination of resistant clones and strains with novel resistance mechanisms, is a major obstacle in gonorrhea control (8).

Strategies for gonorrhea control have relied on the use of highly effective and often single–dose therapies administered at the time of diagnosis. In response to the emergence of penicillinase–producing N. gonorrhoeae, N. gonorrhoeae with plasmid–mediated tetracycline resistance and N. gonorrhoeae with chromosomally mediated resistance to penicillin and/or tetracycline, the Centers for Disease Control and Prevention (CDC) has advocated the use of expanded–generation cephalosporins or fluoroquinolones as first–line therapy for uncomplicated gonorrhea (4,19). However, strains exhibiting decreased susceptibility to ciprofloxacin have been reported from many countries; strains exhibiting clinically significant resistance to CDC recommended doses of ciprofloxacin (500 mg orally, single–dose) or ofloxacin (400 mg, single–dose) have been reported from Asia, Australia, United Kingdom, United States and Canada (5,11,14–17).

In Brazil, ciprofloxacin is one of the recommended therapies for gonorrhea.

Sixty–five strains of N. gonorrhoeae isolates from 70 male outpatients with uncomplicated urethritis were collected from 2004 to 2005 and successfully tested for ciprofloxacin susceptibility. They were attended at the Sexually Transmitted Disease Service of the University of São Paulo Teaching Hospital.

Clinical samples were collected according to local procedures. Initial growth on Thayer–Martin and presumptive identifications based on Gram stain, colony morphology, carbohydrate use, and oxidase test were carried out (10). MIC was determined by the agar dilution method, as recommended by the National Committee for Clinical Laboratory Standards (16). Isolates with MIC of ³ 1.0 µg/ml for ciprofloxacin were considered resistant, whereas intermediate susceptibility was defined as MIC of 0.12 to 0.5 µg/ml (12). The results of the isolates were: 3.07% resistant to ciprofloxacin (MIC ³ 1.0 µg/ml); 4.61% presented reduced susceptibility and 92.3% susceptible (Fig. 1).



Fluoroquinolones, such as ciprofloxacin or ofloxacin, are highly effective as an oral single–dose treatment for uncomplicated infections caused by gonococci strains, including those with previously documented types of resistance (3,6).

The increase in fluoroquinolone resistance has also been substantial in some countries: in Hong Kong, it increased from 7.7% in 1995 to 24% in 1996; in Singapore, it increased from 0.3% in 1993 to 3.5% in 1996; and in Australia it increased from 0.1% in 1992 to 2.6% in 1996 (9). Recently the gonococci resistance to fluoroquinolone antimicrobials, ciprofloxacin in particular, is emerging all over the world, such as in Austria, Korea, Japan, United States, and Canada (2,13,14,18,20), and seriously compromises the treatment efficacy. In Brazil it had not been demonstrated before (1,7).

Periodic monitoring of the antimicrobial susceptibility profile of N. gonorrhoeae strains provides essential clues regarding the emergence of drug resistance and treatment options.

This communication indicates that N. gonorrhoeae fluoroquinolone resistance is emerging in Brazil with these first–five strains of gonococci exhibiting decreased susceptibility or resistance to ciprofloxacin, which is one of the protocol choices for gonorrhea treatment.



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Submitted: November 09, 2006; Returned to authors for corrections: January 11, 2007; Approved: March 15, 2007.



* Corresponding Author. Mailing address: Cidade Universitária "Zeferino Vaz", s/n, Barão Geraldo – Campinas, 13083–970São Paulo, Brasil
Tel.: (19) 3289–4107. E–mail:

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