We investigated the third-generation
cephalosporins-resistant
Shigella and its
genotype in Ningbo,
China,providing a basis for
disease prevention and control.Pathogenic
bacteria were analyzed by direct isolation combined with enrichment
culture isolation.Antimicrobial susceptibility was determined by K-B disk
diffusion method and
PCR was used for detecting
multidrug resistance genes like CTX-M,OXA,TEM and SHV.BLAST
analysis was used to determine the
genotype.Results showed that 69
strains of third-generation
cephalosporins-resistant
Shigella were detected by
drug sensitivity screening,
accounting for 74.19% of ESBLs
Shigella.
Drug resistance gene CTX-M(CTM-M-1 and CTM-M-9),OXA and TEM were detected.The
detection rate were 79.71%,79.01% and 26.09% respectively.With no CTX-M-2 and SHV,
DNA sequence alignment showed CTX-M-1 group were mainly of CTX-M-15 type besides seven other types;CTX-M-9 group were mainly of CTX-M-14 type besides six other types;49
strains of OXA and 18
strains of TEM were sequenced to be type 1 (OXA-1 and TEM-1 type).The 21
Shigella strains carrying more than two
drug resistance genes accounts for 30.43 %.
Shigella in Ningbo has high third-generation
cephalosporins-resistance rate and many kinds of ESBLs
enzymes were detected.The mainstream
enzyme type was CTX-M,meanwhile they also carried a variety of
drug resistance genes,which could bring difficulties to
disease prevention and control.The high
carrying rate of OXA-1 type suggests that we should pay more
attention.The
detection rate of group B was higher than that of group D,including not only the
phenotype resistance but also the
drug-resistance
genes;these findings
will be useful in the study of the
drug resistance prevalence of
Shigella.