Drug resistance to Cephalosporins of major intestinal pathogens causing infectious diarrhea in Beijing

Objective To understand the drug resistance to Cephalosporins of major intestinal pathogens causing infectious diarrhea in Xicheng district of Beijing. Methods A total of 187 strains of intestinal pathogens causing infectious diarrhea were collected in Xicheng district from 2008 to 2011. Extended spectrum -lactamaseas (ESBLs) was detected by using polymerase chain reaction (PCR), then the sequencing for PCR positive products was performed, the sequencing results were aligned with those in GenBank to determine pathogens' genetypes. The drug susceptibility of the pathogens to 8 kinds of Cephalosporins were performed by Kirby-Bauer method. Results Among the 187 strains, 34 strains carrying ESBLs resistant gene were detected, 33 were Shigella strains and 1 was Salmonella strain. Among 34 strains carrying ESBLs resistant gene, 18 were strains carrying OXA-1 subtype resistant gene, 11 were strains carrying CTX-M-14 subtype and 5 were strains carrying 2 kinds of ESBLs resistant gene; The drug susceptibility test results showed that 40% of intestinal pathogens were resistant to Cephalothin, which was highest in 8 kinds of Cephalosporins. Among intestinal pathogens which resistant to more then one kind of Cephalosporins, the resistant rate of Shigella was 81%, the resistant rate of Vibrio parahaemolyticus was 46% and the resistant rate of Salmonella was 33%. The analysis on epidemiological data indicated that the highest resistant rate was detected in age group 20-29 years (27%), followed by the age groups 40 years (23%) and age group 10 years (21%). Conclusion Shigella had high resistant rate to Cephalosporins and had high carrying rate of ESBLs resistant gene. OXA-1 and CTX-M-14 subtype were the major ESBLs resistant gene types. The detection rate of resistant strain was highest in age group 20-29 years.