Emergence of in vitro resistance to fluoroquinolones in Neisseria gonorrhoeae isolated in Japan

Abstract

To investigate emerging fluoroquinolone resistance in Neisseria gonorrhoeae isolated in Japan, we compared the in vitro antimicrobial susceptibilities of 79 gonococcal isolates from 1992 through 1993 to 14 fluoroquinolones and 14 other antibiotics with those of 27 isolates from between 1981 and 1984. The MICs at which 90% of the isolates were inhibited by nine fluoroquinolones, including norfloxacin, enoxacin, ofloxacin, ciprofloxacin, tosufloxacin, lomefloxacin, fleroxacin, levofloxacin, and sparfloxacin, for isolates from 1992 to 1993 were 8-or 16-fold higher than those for isolates from 1981 to 1984. Furthermore, the MICs at which 90% of the isolates were inhibited by five fluoroquinolones, including OPC-17116, T-3761, DU-6859a, AM-1155, and Q-35, that have recently been synthesized but have not yet been introduced for clinical use in Japan for isolates from 1992 to 1993 were also 2-to 16-fold higher than those for isolates from 1981 to 1984. The gonococcal isolates from 1992 to 1993 showed no significant decreases in susceptibility to ␤-lactams, tetracyclines, macrolides, and spectinomycin, compared with those for isolates from 1981 to 1984. Our data indicate that the incidence of gonococcal strains with decreased susceptibilities to fluoroquinolones is increasing in Japan.

Tendency toward increase in the frequency of isolation of β-lactamase-nonproducing Neisseria gonorrhoeae exhibiting penicillin resistance, and recent emergence of multidrug-resistant isolates in Japan

“…[7][8][9] In the present study, the MIC 90 of ciprofloxacin in 1999 was found to have increased by up to 32 times as compared with the value in 1995, and treatment failure, probably due to the use of the drug in divided doses, was noted in some cases. On the contrary, only small numbers of gonococcal isolates showing such a decrease in susceptibility were detected in the United States, probably because the drug was commonly administered as a large single dose to patients with gonorrhea there.…”

“…2,3 Recent in-vitro surveillance data on populations of gonococcal strains and their antimicrobial resistance spectra show that the temporal and geographic distribution of resistant phenotypes varies. [4][5][6] In particular, attention has been focused on the increasing emergence of isolates resistant to the antibiotics used for single oral-dose therapy in cases of uncomplicated gonorrhea, such as penicillin and fluoroquinolones, [7][8][9] which are considered the therapeutic drugs of first choice worldwide. The frequency of isolation of penicillinase-producing Neisseria gonorrhoeae (PPNG, exhibiting plasmid-mediated penicillin resistance) began to increase markedly in the early 1980s, and reached about 10% in Japan and Western countries.…”

Antimicrobial susceptibility patterns of gonococcal isolates in Pretoria, South Africa, over a 20-year period (1984-2004)

“…15,16 Antimicrobial surveillance of gonococcal isolates from various centres in South Africa indicated that the isolates were susceptible to ciprofloxacin. 6,7 More recently, the first ciprofloxacin-resistant N. gonorrhoeae isolates were detected in KwaZulu-Natal.…”

Genotypic Evolution in a Quinolone-Resistant <i>Neisseria gonorrhoeae</i> Isolate from a Patient with Clinical Failure of Levofloxacin Treatment

“…N. gonorrhoeae was identified as gram-negative diplococci and by oxidase reaction and sugar utilization patterns. The minimum inhibitory concentration (MIC) for isolates was determined as described previously [1]. ß-Lactamase production was tested by an acidometric assay (ß-check; Pfizer Pharmaceuticals Inc., Japan).…”

“…In a previous study, we demonstrated that the antimicrobial activity of levofloxacin against gonococcal isolates was 4-fold stronger than that of ofloxacin [1]. This agent is also more potent against Chlamydia trachomatis than ofloxacin [2].…”