Levofloxacin and sitafloxacin regimens effective for Haemophilus influenzae-positive urethritis

28 November, 2018

Both levofloxacin and sitafloxacin regimens – recommended for the treatment of nongonococcal urethritis (NGU) in Japan – were found to be microbiologically effective for Haemophilus influenzae-positive NGU.

Urethritis is one of the most common sexually-transmitted diseases among heterosexual men. Various microorganisms – including bacteria, viruses, and protozoa – have been reported to cause NGU; an increasing number of Haemophilus spp. have been detected in men with NGU.1 In a previous study, the authors reported a 5.2%, 7.4%, and 14.3% prevalence of H. influenzae in men with acute urethritis (n=424), NGU (n=297), and non-chlamydial NGU (n=154), respectively.2

The clinical data of 68 men with H. influenzae urethritis treated with ceftriaxone, levofloxacin, sitafloxacin, or azithromycin were retrospectively retrieved from the iClinic in Sendai, Japan; patients with culture-positive results for H. influenzae at their first visits between January 2009 and December 2015 were included.1

There have been few studies on antimicrobial treatment for H. influenzae-positive NGU – thus, the current study aimed to establish the efficacy of antimicrobial agents recommended for the treatment of acute urethritis against H. influenzae-positive NGU.

The Japanese Guideline for Clinical Research of Antimicrobial Agents on Urogenital Infections recommends response assessment for microbiological outcome (ie, whether the causative pathogen is eradicated) 14–28 days after completion of NGU therapy in patients with Chlamydia trachomatis and Mycoplasma genitalium NGU.3 All men treated with ceftriaxone (n=2), levofloxacin (n=3), or sitafloxacin (n=20) were reported to have negative results for H. influenzae between 14 and 28 days after treatment.1 In addition, in 3 of the 5 men with azithromycin treatment failure following attempts to eradicate H. influenzae, subsequent treatment with either levofloxacin or sitafloxacin resulted in eradication of the causative pathogen.1 Pretreatment isolates of H. influenzae from the patients were also recultured for antimicrobial susceptibility testing – isolates with decreased susceptibility to tetracyclines were reported to be susceptible to ceftriaxone, levofloxacin, sitafloxacin, and azithromycin.

The authors concluded that fluoroquinolone regimens i.e., levofloxacin and sitafloxacin – recommended for the treatment of NGU targeting C. trachomatis and M. genitalium in Japan – are also effective against H. influenzae-positive NGU.


Haemophilus influenzae isolated from men with acute urethritis: Its pathogenic roles, responses to antimicrobial chemotherapies, and antimicrobial susceptibilities.

PMID: 28282645

DOI: 10.1097/OLQ.0000000000000573

Link: https://www.ncbi.nlm.nih.gov/pubmed/28282645


  1. Ito S, et al. Sex Transm Dis 2017;44:205-210.
  2. Ito S, et al. Int J Urol 2016;23:325-331.
  3. Yasuda M, et al. J Infect Chemother 2011;17:579-594.