[Analysis of etiological surveillance results of Shigella spp between 2009 and 2010 in Henan province].

Objective: To explore the etiologic characteristics of bacillary dysentery found in Henan province, between year 2009 and 2010.

Methods: In order to explore the distribution of bacterial types, drug susceptibility and the virulence gene carrier situation, 482 strains of Shigella isolated in Henan province between 2009 and 2010 were pathogen-detected and analyzed by serotype screening, anti microbial sensitivity test and PCR methods.

Results: The 482 isolated strains were confirmed to be Shigella by both morphological and biochemical tests. The Shigella strains were divided into 13 serotypes in 2 groups, namely Shigella flexneri (B group) accounting for 72.0% (347/482) and Shigella sonnei (D group), accounting for 28.0% (135/482). The detection rate of Serotype F2a, as the dominant type of Shigella flexneri, decreased from 43.4% (106/245) in 2009 to 33.8% (80/237) in 2010; while the detection rate of Shigella sonnei increased from 13.1% (32/245) to 43.5% (103/237) in the same period. The results of microbial sensitivity tests carried out in year 2009 and 2010, both showed that over 98% of the 185 studied strains were resistant to ampicillin (AMP), trimethoprim-pyrimidine (TMP), tetracycline (TE), streptomycin (S) and nalidixic acid (NA).182 strains were recruited in the virulence factors detection, 67.6% (123/182) of which carried Shigella Enterotoxin 1B (set1B), Shigella Enterotoxin 2 (set2), invasive plasmid antigen H (ipaH) or invasion-related virulence factors (ial) and 24.2% (44/182) of which carried 3 virulence factors mentioned above.

Conclusion: The prevalent serotypes of Shigella in Henan province have changed in recent years. The isolated strains showed high resistance to common antibacterial drugs and generally carried virulence factors.