Antimicrobial Resistance of Shigella spp. isolated in the State of Pará, Brazil

Abstract

Introduction: Shigella spp. are Gram-negative, nonsporulating, rod-shaped bacteria that belong to the family Enterobacteriaceae and are responsible for shigellosis or bacillary dysentery, an important cause of worldwide morbidity and mortality. Methods: We studied the antibiotic resistance profiles of 122 Shigella spp. strains (81 S. flexneri, 41 S. sonnei, 1 S. boydii) isolated from patients (female and male from 0 to 80 years of age) presenting diarrhea in different districts of the State of Pará, in the North of Brazil. The antibiotic resistance of the strains, isolated from human fecal samples, was determined by the diffusion disk method and by using the VITEK-2 system. Results: The highest resistance rate found was the resistance rate to tetracycline (93.8%), followed by the resistance rate to chloramphenicol (63.9%) and to trimethoprim/sulfamethoxazole (63.1%). Resistance to at least three drugs was more common among S. flexneri than S. sonnei (39.5% vs. 10%). Six (4.9%) strains were susceptible to all the antibiotics tested. All strains were susceptible to cefotaxime, ceftazidime, ciprofloxacin, nalidixic acid and nitrofurantoin. Conclusions: High rates of multidrug resistance in Shigella spp. are a serious public health concern in Brazil. It is extremely important to continuously monitor the antimicrobial resistances of Shigella spp. for effective therapy and control measures against shigellosis.

Shigella in Brazilian children with acute diarrhoea: prevalence, antimicrobial resistance and virulence genes

“…Although Brazil is a developing country, the vast majority of isolates we obtained were S. sonnei (≅ 90%). This finding is similar to recent results from El Salvador, but in contrast to previously reported data for our region, states of Rondônia, Pará (PA) and Piauí (Queiroz et al 1987, Diniz-Santos et al 2005, Silva et al 2008, Bastos & Loureiro 2011, Nunes et al 2012. In fact, S. sonnei is the most common Shigella species isolated in industrialised countries (Ina et al 2003, Navia et al 2005, Niyogi 2005.…”

“…All isolates were sensitive to ciprofloxacin and nalidixic acid (Bastos & Loureiro 2011). The S. flexneri and S. sonnei strains studied by Nunes et al (2012) in an investigation conducted in Northeast Brazil were all susceptible to nalidixic acid, ceftriaxone and ciprofloxacin.…”

Molecular and phenotypic characterization of strains of Shigella sonnei isolated over 31 years suggests the circulation of two prevalent subtypes in São Paulo State, Brazil

“…have been reported in both Brazil and worldwide (Izumiya et al, 2009;Bastos & Loureiro, 2011;Nunes et al, 2012;Gonz alez-Torralba et al, 2015). In this work, 45 (62.5 %) S. sonnei strains were resistant to at least one antimicrobial tested.…”

“…Also, monitoring of resistant strains of species of the genus Shigella is essential in Brazil and the rest of the world, because in some cases of shigellosis the use of antimicrobials is required (Bastos & Loureiro, 2011;Nunes et al, 2012). First-line antimicrobials such as trimethoprim-sulfamethoxazole and ampicillin can be used in the treatment of shigellosis, but resistance to these drugs has been increasing in the USA (CDC, 2013(CDC, , 2015.…”

Authors’ reply

“…Realmente, prevalência elevada de amostras de Shigella resistentes a essa associação de antimicrobianos tem sido observada em diferentes regiões do Brasil [4][5][6][7][8] De acordo com recomendação do Ministério da Saúde, a indicação de drogas antimicrobianas para tratamento de pacientes com shigelose pode ser feita independente de comprovação por coprocultura e antibiograma 2 . Levando-se em consideração que, na grande maioria dos casos, o tratamento é instituído sem a realização de coprocultura -teste pouco sensível, dispendioso e demorado -e, consequentemente, sem o estabelecimento do perfil de suscetibilidade a antimicrobianos do agente etiológico em questão, opções seguras de tratamento, baseadas em dados epidemiológicos locais, precisam ser adotadas.…”