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Volume 20, Number 5—May 2014


Shigella spp. with Reduced Azithromycin Susceptibility, Quebec, Canada, 2012–2013

Christiane GaudreauComments to Author , Sapha Barkati, Jean-Michel Leduc, Pierre A. Pilon, Julie Favreau, and Sadjia Bekal
Author affiliations: Centre Hospitalier de l’Université de Montréal–Hôpital Saint-Luc, Montreal, Quebec, Canada (C. Gaudreau, S. Barkati, J.-M. Leduc, J. Favreau); Université de Montréal, Montreal (C. Gaudreau, S. Barkati, J.-M. Leduc, P.A. Pilon, S. Bekal); Agence de la Santé et des Services Sociaux de Montréal-Santé Publique, Montreal (P.A. Pilon); Laboratoire de Santé Publique du Québec/Institut National de Santé Publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada (C. Gaudreau, S. Bekal)

Main Article

Table 2

Characteristics and antimicrobial susceptibility of 4 Shigella isolates with reduced azithromycin susceptibility, Montreal, Quebec, Canada, January 2012–April 2013*

Shigella species ST PV† AZM, mg/L‡ AMP, mg/L TMP/SMX, mg/L CIP
mg/L CRO,
 mg/L TET, mg/L CHL, mg/L NAL mm
S. flexneri 2a 15 256 <2 (S) >320 (R) 0.016 <1 >128 0.5 (S) 27
S. flexneri 2a 16 64 >32 (R) >320 (R) 0.016 <1 >128 128 (R) 27
S. flexneri 3a 6 >256 >32 (R) <20 (S) 0.016 <1 >128 >256 (R) 24–28
S. sonnei 101,105§ >256 >32 (R) >320 (R) 0.016 <1 >128 >256 (R) 23–27

*The susceptibility and resistance break points for AMP, CIP, TMP/SMX, CRO, TET, CHL, and NAL were Clinical and Laboratory Standards Institute Enterobacteriaceae break points (12). ST, serotype; PV, pulsovar; AZM, azithromycin; AMP, ampicillin; TMP/SMX, trimethoprim/sulfamethoxazole; CIP, ciprofloxacin; CRO, ceftriaxone; TET, tetracycline; CHL, chloramphenicol; NAL, nalidixic acid; S, susceptible; R: resistant; –, not applicable.
†PV was determined by XbaI and BlnI pulsed-field gel electrophoresis patterns.
‡The criterion for elevated azithro MIC was >16 mg/L (13).
§S. sonnei PVs 101 and 105 were related and had 2 different pulsed-field gel electrophoresis bands.

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