Epidemiology and genetic characterization of <i>Shigella flexneri</i> strains isolated from three paediatric populations in Egypt (2000–2004)

Ahmed, Salwa F.; Riddle, Mark S.; Wierzba, Thomas F.; Messih, I. A. Abdel; Monteville, M. R.; Sanders, John W.; Klena, John D.

doi:10.1017/s095026880600642x

Cited by 29 publications

(35 citation statements)

References 40 publications

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“…Shigella isolates belonging to each serotype had approximately 80-100 % similarity (Fig. 1), in accordance with other such findings (Ahmed et al, 2006;Sirisriro et al, 2006). S. dysenteriae type 1 isolated in this study was a different clone from the previous isolates from this region (Fig.…”

Section: Discussionsupporting

confidence: 91%

Genetic characteristics and changing antimicrobial resistance among Shigella spp. isolated from hospitalized diarrhoeal patients in Kolkata, India

Ghosh

Pazhani

Chowdhury

et al. 2011

Journal of Medical Microbiology

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To study the prevalence pattern and trends in the phenotypic and genetic characteristics of shigellae, we tested 212 isolates isolated from diarrhoeal patients admitted to the Infectious Diseases Hospital, Kolkata, India, from November 2007 to October 2010. Prevalence of Shigella spp. was higher in the .5 years age group (69 %) than in children in the ,5 years age group (31 %). Serotypes 2a, 3a and untypable isolates of Shigella flexneri were frequently detected. An increase in the isolation of Shigella sonnei (15 %) is a novel trend in this region. Fluoroquinolone resistance among S. flexneri serotypes 2a, 3a and other serogroups of shigellae is another evolving trend. The set gene was exclusively present in S. flexneri 2a, and the sen gene was detected in all serogroups. PFGE revealed the grouping of S. flexneri isolates according to their serotypes with approximately 80-100 % similarity, whilst Shigella dysenteriae type 2 and S. sonnei were clonal in nature. There was no demarcation in the prevalence of serotypes, antimicrobial resistance or clonality between the two age groups. INTRODUCTIONShigellosis remains a considerable public-health problem in many parts of the world. About 125 million cases of Shigella infection occur annually in Asia, of which approximately 14 000 are fatal (Bardhan et al., 2010). The distribution of serogroups of Shigella spp. differs from country to country: Shigella flexneri, Shigella sonnei and Shigella boydii serogroups are predominant in developing countries, whilst S. sonnei is frequently reported in industrialized countries. Prevalence of Shigella dysenteriae is mostly reported from South Asia and sub-Saharan Africa (Kotloff et al., 1999). Unlike other acute diarrhoeal illnesses that require adequate fluid replacement by either oral or intravenous rehydration, shigellosis needs antimicrobial therapy to reduce the duration of the illness and to prevent transmission to close contacts. Shigella spp. have developed perpetual resistance to ampicillin and trimethoprimsulfamethoxazole, which have been used in paediatric cases during the past two decades. Fluoroquinolones, ceftriaxone and pivmecillinam are the antibiotics currently recommended by the World Health Organization for the treatment of dysentery in children, as these drugs are effective at reducing mortality caused by Shigella spp. (Traa et al., 2010). These drugs are also effective among immunocompromised children, including neonatal patients, suffering from infections caused by multi-drugresistant strains of Salmonella and Shigella spp. (Leibovitz, 2006). The use of antimicrobials for the treatment of shigellosis varies from country to country. Pivmecillinam is not the drug of choice for the treatment of diarrhoea in many countries, but is being used in Bangladesh (Rahman et al., 2007). Ceftriaxone is an ideal drug for the treatment of shigellosis in regions where fluoroquinolone resistance is common. The American Academy of Pediatrics and the Infectious Diseases Society of America recommend azithromycin as an alternativ...

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Section: Discussionsupporting

confidence: 91%

Genetic characteristics and changing antimicrobial resistance among Shigella spp. isolated from hospitalized diarrhoeal patients in Kolkata, India

Ghosh

Pazhani

Chowdhury

et al. 2011

Journal of Medical Microbiology

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“…In a recent study, S. flexneri serotype 1c emerged as an important isolate (17%) in three pediatric populations in Egypt [5]. The isolates were highly resistant to AM, tetracycline and sulfatrimethoxazole, with some showing simultaneous resistance to two or more antibiotics (multi-drug resistance phenotypes, MDR).…”

Section: Resultsmentioning

confidence: 99%

Genetic characterization of antimicrobial resistance of Shigella flexneri 1c isolates from patients in Egypt and Pakistan

Ahmed

Klena

Husain

et al. 2013

Annals of Clinical Microbiology and Antimicrobials

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BackgroundShigella flexneri serotype 1c emerged as a critical isolate from children in Egypt and Pakistan. The pattern of antimicrobial susceptibility (AMS) and resistance genes of this serotype have yet to be characterized.FindingsSixty nine S. flexneri 1c isolates isolates were identified from both Egypt (n-46) and Pakistan (n = 23) and tested for AMS by disk diffusion method and minimal inhibitory concentrations were also determined. Isolates were genotyped by pulsed field gel electrophoresis (PFGE) and five relevant resistance genes (blaTEM, blaSHV, blaOXA, sulI and sulII) were detected by polymerase chain reaction (PCR) and confirmed by DNA sequencing. High resistance was observed in all isolates for ampicillin (AM >96%); trimethoprim-sulphamethoxazole and tetracycline (>88%). Most AM-resistant isolates from Egypt (70%) harbored blaTEM resistance, while 52% of isolates from Pakistan expressed blaOXA. All isolates were closely related by PFGE, irrespective of source or time of collection. The sulII gene was present in 100% of isolates from pediatric cases in Egypt, 65% of Pakistan isolates, and 53% of isolates from older Egyptian patients.ConclusionsWhile different Shigella serotypes gathered in specific genotypic groups, 1c serotype isolates formed multiple clusters. Although AMS was considerably high to most commonly used drugs, genetic determinants were variable between countries over time. The data stress the need for a more careful selection of antibiotics in the treatment of shigellosis.

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“…The distribution of Shigella species and Shigella flexneri serotypes from selected studies in Latin America, Asia and Africa. Several population-based surveillance studies lasting at least 2 years used extensive serotyping methods (including either commercial absorbed animal sera or monoclonal antibodies for Shigella flexneri typing) [6][7][8][9][129][130][131] . In all countries, S. flexneri 2a is the single most important S. flexneri subserotype.…”

Section: Shigella Vaccine Strategiesmentioning

confidence: 99%

Clinical trials of Shigella vaccines: two steps forward and one step back on a long, hard road

et al. 2007

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More than 50 years of research has yielded numerous Shigella vaccine candidates that have exemplified both the promise of vaccine-induced prevention of shigellosis and the impediments to developing a safe and effective vaccine for widespread use, a goal that has yet to be attained. This Review discusses the most advanced strategies for Shigella vaccine development, the immune responses that are elicited following disease or vaccination, the factors that have accelerated or impeded Shigella vaccine development and our ideas for the way forward.At the end of the 19th century, as epidemics of bacillary dysentery accompanied by high mortality spread across Japan, the young microbiologist Kiyoshi Shiga examined dysenteric stools and isolated a bacterium that was agglutinated by serum from convalescent patients but not from patients with acute disease [1][2][3] (FIG. 1). That bacterium -known today as Shigella dysenteriae 1 -was the first identified member of the genus Shigella. Four Correspondence to M.L. mlevine@medicine.umaryland.edu. Competing interests statement:The authors declare no competing financial interests. Links NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptShigella species (or groups) are now recognized: S. dysenteriae (group A), which has 15 serotypes; Shigella flexneri (group B), which has 14 classical serotypes and subserotypes; Shigella boydii (group C), which has 20 serotypes; and Shigella sonnei (group D), which has single serotype 4 (TABLE 1).There has been resurgent interest in Shigella as a human pathogen, driven by the availability of more precise data on the disease burden 5-8 , emerging antibiotic resistance 9,10 and the fact that mucosally invasive Shigella, which often cause dysentery (gross blood in diarrhoeal stools), are less amenable to the salutary effects of oral rehydration than non-invasive pathogens that cause watery diarrhoea, such as Vibrio cholerae and enterotoxigenic Escherichia coli. The target populations for the use of Shigella vaccines include infants and young children in developing countries (in which the peak incidence occurs at 12-47 months of age and the S. flexneri serotypes predominate) 5-7 .S. dysenteriae 1, which produces Shiga toxin and typically carries R factors that encode resistance to multiple antibodies, waxes and wanes as a cause of epidemic severe disease in the world's least developed countries [11][12][13][14] Few bacterial pathogens have had their pathogenesis or interactions with mammalian tissues elucidated so precisely at the cellular and subcellular levels as Shigella spp. 20,21 Nevertheless, progress in attaining safe and effective Shigella vaccines has faltered. Herein, we review recent and old clinical trials that have evaluated the safety, immunogenicity and efficacy of candidate Shigella vaccines. We relate the bassis for the most popular strategies (BOX 2), the relevance of the different immune responses measured, the factors that have favoured or impeded vaccine development and, most importantly, the less...

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Epidemiology and genetic characterization of Shigella flexneri strains isolated from three paediatric populations in Egypt (2000–2004)

Cited by 29 publications

References 40 publications

Genetic characteristics and changing antimicrobial resistance among Shigella spp. isolated from hospitalized diarrhoeal patients in Kolkata, India

Genetic characteristics and changing antimicrobial resistance among Shigella spp. isolated from hospitalized diarrhoeal patients in Kolkata, India

Genetic characterization of antimicrobial resistance of Shigella flexneri 1c isolates from patients in Egypt and Pakistan

Clinical trials of Shigella vaccines: two steps forward and one step back on a long, hard road

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