High rates of quinolone-resistant strains of Shigella sonnei in HIV-infected MSM

There is increasing evidence that shigellosis is a predominantly sexually transmitted disease among men who have sex with men (MSM) and that infection with the human immunodeficiency virus (HIV) is a risk factor for shigellosis. Retrospective analysis of antibiotic resistance profiles of Shigella species isolated from stool specimens of patients presenting with diarrhea from January 2010 to July 2012 in three German outpatient clinics specialized in HIV care. Among 79 cases of Shigella sonnei, 56 occurred in HIV-infected MSM, while 23 were observed in HIV-negative MSM. High resistance rates (> 90 %) were found for doxycycline, tetracycline, aminoglycosides, all cephalosporins of first and second generations tested, and trimethoprim/sulfamethoxazole. In total, 54 % of cases were resistant to ciprofloxacin. Compared to negative subjects, HIV-infected MSM had a significantly higher rate of quinolone resistance. For ciprofloxacin, the resistance rates were 66 versus 24 %, respectively (p = 0.0016). Individual resistance patterns did not indicate that this was due to a limited outbreak. Rates of resistance to other antibiotics than quinolones showed no differences between HIV-infected and HIV-negative cases. No resistance was found for carbapenems or newer cephalosporins such as ceftriaxone. The high rates of S. sonnei isolates resistant to quinolones and other traditional antibiotics are of concern. Innovative prevention efforts are urgently needed. The empirical use of quinolones in HIV-infected patients presenting with S. sonnei infection is no longer recommended.