title: Relationship between drug resistance and the clustered, regularly interspaced, short, palindromic repeat-associated protein genes cas1 and cas2 in Shigella from giant panda dung.
abstract: BACKGROUND
  To detect drug resistance in Shigella obtained from the dung of the giant panda, explore the factors leading to drug resistance in Shigella, understand the characteristics of clustered, regularly interspaced, short, palindromic repeats (CRISPR), and assess the relationship between CRISPR and drug resistance.
  
  
  METHODS
  We collected fresh feces from 27 healthy giant pandas in the Giant Panda Conservation base (Wolong, China). We identified the strains of Shigella in the samples by using nucleotide sequence analysis. Further, the Kirby-Bauer paper method was used to determine drug sensitivity of the Shigella strains. CRISPR-associated protein genes cas1 and cas2 in Shigella were detected by polymerase chain reaction (PCR), and the PCR products were sequenced and compared.
  
  
  RESULTS
  We isolated and identified 17 strains of Shigella from 27 samples, including 14 strains of Shigella flexneri, 2 strains of Shigella sonnei, and 1 strain of Shigella dysenteriae. Further, drug resistance to cefazolin, imipenem, and amoxicillin-clavulanic acid was identified as a serious problem, as multidrug-resistant strains were detected. Further, cas1 and cas2 showed different degrees of point mutations.
  
  
  CONCLUSIONS
  The CRISPR system widely exists in Shigella and shares homology with that in Escherichia coli. The cas1 and cas 2 mutations contribute to the different levels of resistance. Point mutations at sites 3176455, 3176590, and 3176465 in cas1 (a); sites 3176989, 3176992, and 3176995 in cas1 (b); sites 3176156 and 3176236 in cas2 may affect the resistance of bacteria, cause emergence of multidrug resistance, and increase the types of drug resistance.
authors.affiliation: College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, China China Conservation and Research Centre for the Giant Panda, Wolong, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Ren
authors.forename: Lin-Hua
authors.initials: LH
authors.lastname: Deng
authors.forename: Ri-Peng
authors.initials: RP
authors.lastname: Zhang
authors.forename: Cheng-Dong
authors.initials: CD
authors.lastname: Wang
authors.forename: De-Sheng
authors.initials: DS
authors.lastname: Li
authors.forename: Li-Xin
authors.initials: LX
authors.lastname: Xi
authors.forename: Zhen-Rong
authors.initials: ZR
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Yang
authors.forename: Jie
authors.initials: J
authors.lastname: Huang
authors.forename: Yang-Ru
authors.initials: YR
authors.lastname: Zeng
authors.forename: Hong-Lin
authors.initials: HL
authors.lastname: Wu
authors.forename: San-Jie
authors.initials: SJ
authors.lastname: Cao
authors.forename: Rui
authors.initials: R
authors.lastname: Wu
authors.forename: Yong
authors.initials: Y
authors.lastname: Huang
authors.forename: Qi-Gui
authors.initials: QG
authors.lastname: Yan
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D064130:CRISPR-Associated Proteins / Q000235:genetics*; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D005243:Feces / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012760:Shigella / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification; D001503:Ursidae / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D064130:CRISPR-Associated Proteins; D012336:RNA, Ribosomal, 16S