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

Abstract

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...

Antibiotic resistance—the need for global solutions

“…258 Further, reports of emerging resistance to second-line antibiotics such as third-generation cephalosporins and azithromycin are of great concern. 259 Increased resistance to fl ouro quinolones and macrolides is also being reported for campylobacter. Ciprofl oxacin resistance rates range from 65% to 88% in Bangladesh, 260 whereas rates of resistance from African countries range from 5% to 38%.…”

Effectiveness of aqueous and hydroalcoholic extracts of Acanthospermum australe (Loefl.) Kuntze against diarrhea-inducing bacteria

“…against pathogenic or potentially pathogenic enterobacteria. Our findings are important, however, since S. dysenteriae, which causes diarrhea, fever and abdominal pain, often with serious complications, has been classified as an urgent threat in the United States (Centers for Disease Control and Prevention, 2013) because of acquired resistance to first-line and other important antibiotics (Takeda et al, 2011;Zhang et al 2014). Moreover, E. faecalis is one of the leading causes of nosocomial infections, most of which occur after puncturing trauma or surgery of the abdomen.…”

Molecular characterization of antimicrobial resistance in clinical Shigella isolates during 2014 and 2015: trends in South India

“…Similar results were reported from Manipal and Puducherry in South India, where >90 percent of the isolates were S. flexneri. 4,13 In an earlier study conducted in Vellore, South India flexneri was the most common serogroup (57.6%) followed by S. sonnei (31%). 14 In recent years, an epidemiological shift in Shigella serogroups was reported.…”

“…3 Although shigellosis is primarily self-limiting, antibiotics are recommended for reducing illness duration and for preventing transmission; the current drugs of choice are fluoroquinolones and third generation cephalosporins. 4 However, antimicrobial resistance (AMR) is an emerging problem among Shigella spp., particularly in Asia and Africa. 5 Resistance to first line drugs such as ampicillin and trimethoprimsulfamethoxazole has become high.…”