Shigella flexneri with Ciprofloxacin Resistance and Reduced Azithromycin Susceptibility, Canada, 2015

ompA, and htrA); 11 of these ticks were from the patient’s dogs. In all properties where ticks were collected, at least 1 was PCR positive. Thus, we detected R. parkeri in half (4/8) of investigated households. All the sequences generated for the ompA and htrA genes showed 100% identity to sequences from the Rickettsia parkeri strain Portsmouth (GenBank accession no. CP003341.1). We deposited into GenBank the sequences of the ompA gene (KX196265) and htrA gene (KX196266) from samples analyzed in this study. The ompA sequence we obtained for R. parkeri showed 98% identity with Rickettsia sp. strain Atlantic Rainforest (GenBank accession no. GQ855237.1). Although Rickettsia sp. strain Atlantic Rainforest had previously been considered the only SFG Rickettsia in southern Brazil, we demonstrate here the presence of R. parkeri in Rio Grande do Sul in the Pampa biome. We detected R. parkeri infection in A. tigrinum ticks collected at the probable site of infection (the patient’s home) of a confirmed case of human spotted fever. Considering the A. tigrinum tick abundance in southern Brazil and its remarkable ability to parasitize domestic and wild animals (8), in addition to the high R. parkeri infection rate observed (28%), further epidemiologic studies are needed to address the role of A. tigrinum ticks as vector of spotted fever in the Pampa biome. Finally, our results show that, in addition to R. rickettsii and Rickettsia sp. strain Atlantic Rainforest, R. parkeri occurs and might be associated with cases of spotted fever in Brazil. Additional surveys are needed to assess the infection prevalence of R. parkeri in A. tigrinum ticks in other areas of Pampa and in other regions of Brazil.

To the Editor: In 2015, a locally acquired, multidrug-resistant Shigella flexneri infection was identified in Montreal, Quebec, Canada, in an HIV-positive man who had sex with men (MSM). In September, the 53-year-old man consulted his physician at an outpatient clinic after experiencing abdominal pain, fatigue, and diarrhea without blood in stools or fever. The week before the symptom onset, although he had not traveled, he had unprotected oral and anal sexual contact in a Montreal bathhouse with a man visiting Canada from an unknown country. The patient did not work in daycare centers or healthcare facilities, and he was not a food handler. He did not have sex during illness.
He was HIV positive and was receiving antiretroviral treatment; recent CD4 cell count was 480 × 10 6 /L, and HIV viral load was <40 copies/mL. S. flexneri was isolated from his culture of a fecal sample, and Neisseria gonorrhoeae, diagnosed by PCR, was found in a throat specimen. The patient did not have a medical record of other past sexually transmitted infections.
On day 10 of diarrhea, the patient was treated with ceftriaxone, 250-mg dose, intramuscularly, followed by cefixime, 800 mg/day, for 5 days; the patient's condition showed progressive improvement. Two control cultures of fecal specimens were negative 7 and 16 days, respectively, after completion of a regimen of cefixime.
In the United States, Shigella spp. resistant to at least nalidixic acid and azithromycin have been found in Clinical treatment failure has been reported in patients infected with azithromycin-nonsusceptible Shigella isolates treated with this drug (7,8), including 1 of our patients (unpub. data). In a previous study, the mph(A) gene was acquired by 4 of 7 locally acquired Shigella pulse types infecting MSM. This raises concern that reduced Shigella susceptibility to azithromycin is developing rapidly (1). Azithromycin epidemiologic cutoff values for wild-and non-wild-types of S. flexneri and S. sonnei are newly reported by CLSI (8). In recent years, ciprofloxacin-resistant and/or azithromycin-nonsusceptible Shigella spp. acquired during international travel or acquired locally were reported in the United States and in our hospital center (1,3-6; unpub. data). S. flexneri that is resistant to ceftriaxone and ciprofloxacin has been reported in the United States (9). Infections with multidrug-resistant Shigella spp. may be of longer duration and have higher costs (3).
When evaluating patients with diarrhea, physicians should identify risk factors and request bacterial cultures of fecal specimens. Antimicrobial drug susceptibility testing of Shigella isolates is essential for effective antimicrobial drug treatment. Serologic identification and PFGE are essential for epidemiologic purposes for ascertaining clusters or multidrug-resistant Shigella isolates (1,(3)(4)(5). Patients with Shigella infection should be advised about preventive practices such as frequent handwashing and precautions when handling food and water (3). MSM should use barriers during oral, anal, and genital sex and wash their genitals, anus, and hands before and after sex (1,(3)(4)(5).
We suggest obtaining 2 control cultures of fecal specimens on days 2 and 3 after the patient completes  To our knowledge, no other ciprofloxacin-resistant and azithromycin-nonsusceptible Shigella flexneri isolates have been documented in the province of Quebec. No PFGE matches to S. flexneri serotype 2a pulsovar 21 have been identified in Canada. Multidrug-resistant Shigella isolates, including those with both resistance to ciprofloxacin and nonsusceptibility to azithromycin, may be underestimated and incidence may be increasing (1,(3)(4)(5).