ABSTRACT
Objective To understand genetic distribution, drug resistance, molecular typing and the epidemiological relativeness between strains of the Shigella boydii virulence. Methods Nine Shigella boydii strains were isolated form stool samples of patients with diarrhea from the Enteric Disease Clinic of the Second Hospital of Tianjin Medical University in June-October 2015. The strains were identified by biochemical test and serum agglutination test. Antibiotics susceptibility test was carried out using the Kirby-Bauer method. Polymerase chain reaction was used for detecting virulence genes. Pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) technique were used to determine the epidemiological relationship between nine Shigella boydii strains. Results There were three subtypes in nine isolated Shigella boydii samples, including one, three and five isolates inⅠ,Ⅱ,Ⅳsubtypes respectively. All of the 9 isolates were multi-drug resistant. The resistant rate of these strains for ampicillin was 100%(9/9), and then the resistant rates of these strains for ceftazidime, streptomycin, gentamicin, trimethoprim/sulfamethoxazole, cefotaxime, ceftriaxone, norfloxacin and levofloxacin were 1/9, 4/9, 4/9, 4/9, 5/9, 5/9, 6/9, 6/9 and 6/9, respectively. All of these strains were sensitive to amikacin, cefperazone-sulbactam and imipenem. The ipaH was carried by all the testing strains, and none of the strains carried the sen, set1A, set1B, ial, virA, icsA and SigA. The detective rates of pic, sepA and sat were 4/9, 5/9 and 7/9 strains, respectively. Nine shigella boydii strains were divided into 8 PFGE types. The similarity between the spectrums of PFGE was 63.21%-100%. Multilocus sequence typing showed that six isolates were belonged to ST648, two isolates were ST131 and one isolate was ST10. Conclusion Nine isolates of Shigella boydii (divided into three subtyping) isolated from our hospital are multi-drug resistant and they have distant relationships, belonging to the dissemination of case.
ABSTRACT
Objective To study the expression of active efflux pump AdeABC,AdeIJK,AdeFGH,AbeM,AbeS,CraA,MdtL in clinical Acinetobacter baumannii isolates and whether the efflux pumps confers resistance to antibiotics.Methods Thirty-two multi-drug resistant Acinetobacter baumannii islates and 10 sensitive isolates were collected.Genes of the exporter protein were amplified by PCR.The expression of adeB,adeJ,adeG,abeM,abeS,craA,mdtL were examined by real-time fluorescence quantitative RT-PCR.The controlling genes adeRS and adeL were amplified by PCR and sequenced.Results The positivity rates of adeB,adeJ,adeG,abeM,abeS,craA,mdtL were 100％,100％,100％,96.88％,100％,100％ and 93.75％ respectively in 32 multi-drug resistant Acinetobacter baumannii isolates,and all 100％ in 10 sensitive isolates.The difference of expression of adeB,abeM and mdtL were significant( P＜0.001,P =0.001,P=0.013) between 21 multi-drug resistant isolates of C clone and 10 sensitive isolates.The mutations of adeRS existed in 2 multi-drug resistant isolates,no point mutation of adeL.Conclusion The expression of AdeABC,AbeM and MdtL may involved in the resistant mechanisms of the clinical Acinetobacter baumannii islates.
ABSTRACT
Objective To study the expression of active efflux pump AdeABC in clinical Acineto-bacter baumannii islates and whether this efflux pump confers resistance to antibiotics. Methods The anti-biotic susceptibility and the function of efflux pump inhibitor were tested by micro-dilution broth method. The expression of adeB was examined by RT-PCR. The controlling gene adeRS was amplified by PCR and se-quenced. Results Thirty multidrug resistance Acinetobacter baumannii isolates and 5 sensitive isolates for PCR were both abtained the expected products of adeB and adeRS. The mRNA expression of adeB in 15 multidrug resistance(MDR) isolates were positive, but there was no expression of adeB in 5 sensitive iso-lates. The mutations of adeRS existed in 2 MDR isolates. Conclusion The expression of AdeABC may in-volved in the resistant mechanisms of the clinical MDR Acinetobacter baumannii isolates.