OBJECTIVES: In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins and plasmid-mediated quinolone resistance (PMQR), and genetic relatedness among Shigella isolates obtained from Iranian patients. METHODS: A total of 44 Shigella isolates were collected from Iranian patients admitted to Milad Hospital, Tehran, Iran, during 2008-10. Of these, 37 were serotyped and characterized by MIC determination. A subset of eight suspected extended-spectrum β-lactamase (ESBL) producers (six Shigella sonnei phase II and two Shigella flexneri type 1b) were examined for the presence of genes encoding cephalosporin resistance. The presence of PMQR was assessed in one S. flexneri isolate exhibiting low-level resistance to ciprofloxacin and susceptibility to nalidixic acid. PFGE was performed on 25 S. sonnei phase II isolates. RESULTS: Of the isolates, 25 (68%) were S. sonnei phase II, with 5 (14%) S. flexneri, 5 (14%) Shigella dysenteriae type 2, and 2 (5%) Shigella boydii type 2. Resistance to at least threeclasses of antimicrobials was detected in all species. The presence of bla(CTX-M-15) and the AmpC β-lactamase producer bla(CMY-2) was confirmed in five and one S. sonnei phase II isolates, respectively. One of the two S. flexneri type 1b that contained bla(CTX-M-15) also harboured a qnrS1 gene. PFGE identified sevenPFGE profiles; the main cluster included 15 of the strains, suggesting low genetic diversity between isolates or the presence of an endemic clone in Iran. CONCLUSIONS: This is the first known description of ESBL-producing and AmpC β-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread of ESBL-producing and AmpC-β-lactamase-producing Shigella should be implemented.
OBJECTIVES: In this study, we wanted to assess the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins and plasmid-mediated quinolone resistance (PMQR), and genetic relatedness among Shigella isolates obtained from Iranian patients. METHODS: A total of 44 Shigella isolates were collected from Iranian patients admitted to Milad Hospital, Tehran, Iran, during 2008-10. Of these, 37 were serotyped and characterized by MIC determination. A subset of eight suspected extended-spectrum β-lactamase (ESBL) producers (six Shigella sonnei phase II and two Shigella flexneri type 1b) were examined for the presence of genes encoding cephalosporin resistance. The presence of PMQR was assessed in one S. flexneri isolate exhibiting low-level resistance to ciprofloxacin and susceptibility to nalidixic acid. PFGE was performed on 25 S. sonnei phase II isolates. RESULTS: Of the isolates, 25 (68%) were S. sonnei phase II, with 5 (14%) S. flexneri, 5 (14%) Shigella dysenteriae type 2, and 2 (5%) Shigella boydii type 2. Resistance to at least threeclasses of antimicrobials was detected in all species. The presence of bla(CTX-M-15) and the AmpC β-lactamase producer bla(CMY-2) was confirmed in five and one S. sonnei phase II isolates, respectively. One of the two S. flexneri type 1b that contained bla(CTX-M-15) also harboured a qnrS1 gene. PFGE identified sevenPFGE profiles; the main cluster included 15 of the strains, suggesting low genetic diversity between isolates or the presence of an endemic clone in Iran. CONCLUSIONS: This is the first known description of ESBL-producing and AmpC β-lactamase-producing Shigella and of PMQR Shigella in Iran. The emergence of CTX-15, CMY-2 and qnrS1 genes may compromise the treatment of shigellosis. Strategies to minimize the spread of ESBL-producing and AmpC-β-lactamase-producing Shigella should be implemented.
Authors: Angela Lluque; Susan Mosquito; Cláudia Gomes; Maribel Riveros; David Durand; Drake H Tilley; María Bernal; Ana Prada; Theresa J Ochoa; Joaquim Ruiz Journal: Int J Med Microbiol Date: 2015-05-04 Impact factor: 3.473
Authors: Kathryn E Holt; Tran Vu Thieu Nga; Duy Pham Thanh; Ha Vinh; Dong Wook Kim; My Phan Vu Tra; James I Campbell; Nguyen Van Minh Hoang; Nguyen Thanh Vinh; Pham Van Minh; Cao Thu Thuy; Tran Thi Thu Nga; Corinne Thompson; Tran Thi Ngoc Dung; Nguyen Thi Khanh Nhu; Phat Voong Vinh; Pham Thi Ngoc Tuyet; Hoang Le Phuc; Nguyen Thi Nam Lien; Bui Duc Phu; Nguyen Thi Thuy Ai; Nguyen Manh Tien; Nguyen Dong; Christopher M Parry; Tran Tinh Hien; Jeremy J Farrar; Julian Parkhill; Gordon Dougan; Nicholas R Thomson; Stephen Baker Journal: Proc Natl Acad Sci U S A Date: 2013-09-30 Impact factor: 11.205