Molecular epidemiology of Shigella flexneri in a diarrhoea-endemic area of Lima, Peru

Abstract

A year-long community-based study of diarrhoeal diseases was conducted in Canto Grande, a periurban community in Lima, Peru. In 109 (34%) houses out of 323 that were visited, at least one individual was detected with shigellosis. The frequency of the 161 shigella isolates obtained was as follows: 117 S. flexneri (73%), 21 S. boydii (13%), 15 S. dysenteriae (9%), and 8 S. sonnei (5%). Using a non-radioactive ipaH gene probe as a molecular epidemiological tool, a total of 41 S. flexneri strains were shown to be distributed in 25 intra-family comparisons by pairs (icp). Further subdivision, based on a comparison of the serotype, plasmid profile, antibiotic resistances and ipaH hybridization patterns indicated that Group I, with 11 icp (44%), had strains that were identical. Group II with 8 icp (32%), had strains that were different and Group III with 6 icp (24%), had strains with the same serotype and identical ipaH profiles but with differences in other markers. This data indicates that a diversity of shigella clones circulated in this community resulting from both clonal spread and horizontal transfer of genetic elements. Furthermore, ipaH profiling of isolates can be used not only to differentiate between closely related shigella strains but also with other parameters, help to understand the dynamics of the generation of new clones of pathogenic bacteria.

Virulence factors and mechanisms of antimicrobial resistance in Shigella strains from periurban areas of Lima (Peru)

“…Regarding S. flexneri our results are in agreement with previous studies developed in Peru and Chile (Fernandez-Prada et al , 2004) that showed the presence of different circulating strains in periurban areas of Lima. In the case of S. boydii , the heterogeneity of strains is also highlighted by the presence up to 6 different serotypes, with a maximum of 3 isolates each.…”

“…Nonetheless, although recent reports shows a low prevalence in some South American countries such as Brazil or Chile (Bastos and Loureiro, 2011; Hamilton-West et al , 2007; Peirano et al , 2006), other countries such as Argentina have reported a prevalence rate of 7.7% for S. boydii (Rolfo et al , 2012). Our prevalence of 14% for S. boydii is comparable to the prevalence rates seen within the Indian subcontinent, being also in accordance with other studies developed in different Peruvian areas (Kosek et al , 2008; Fernández-Prada et al , 2004). …”

Plasmid Profile Analysis and Antibiotic Resistance Patterns of Shigella Isolates from Kwale County, Kenya

“…A similar study by Seol et al (2006) on S. sonnei in South Korea documented a 70-80kb R-plasmid that was responsible for transfer of sulfamethoxazole-trimethoprim, streptomycin and tetracycline resistance. However, the findings of this study do not correspond to the findings by Fernandez-Prada et al (2004) in Peru. Their study did not find a correlation between presence of a particular plasmid and antibiotic-resistance profile in S. flexneri.…”

ShigellaInfections in Household Contacts of Pediatric Shigellosis Patients in Rural Bangladesh

“…The proportion of shigellosis patient households with Shigella -infected contacts in our study is higher than has been previously reported. In a study in Peru, 34% of households of index shigellosis patients during the 1-week surveillance period had infected contacts ( 20 ). Another study conducted in rural Bangladesh in 1974 found that 19% of members of household compounds (i.e., multiple households living together) developed Shigella infection over a 10-day period after identification of the index shigellosis patient, compared with 7% of members of control household compounds ( 21 ).…”