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Objective To preliminarily understand the genotype characteristics of Toxoplasma gondii in blood of HIV?posi?tive persons in Lincang City,Yunnan Province. Method Two segments of SAG2 gene of T. gondii from blood samples of HIV?positive persons in Lincang City were extracted and amplified by using the nested PCR method and the genotype was identified and compared with the standard strain(Type I)of Toxoplasma gondii. Results Thirty?five SAG2 genes(241 bp)and 35 SAG2 genes(221 bp)of T. gondii were amplified from 170 blood samples of the HIV?positive people,and 4 of each case were selected and digested with enzyme,then 2 aim gene fragments of each case were chosen and compared with the standard strain (Type I)of T. gondii. The digestion of SAG2 gene(241 bp)showed the genotype of the blood samples was Type I or Type II, and the digestion of SAG2 gene(221 bp)confirmed that the genotype was Type I. Conclusion It is preliminarily confirmed that the genotype of T. gondii in blood of HIV?positive persons in Lincang City,Yunnan Province is Type I.
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Objective To investigate the distribution and antibiotic resistance of the K lebsiella pneumoniae strains isolated from clinical infections in terms of serotypes K1 ,K2 and virulence factor rmpA gene .Methods The hypermucoviscous phenotype of K .pneumoniae isolate was determined by string test .K1 and K2 serotypes and rmpA gene were detected using multiplex polymerase chain reaction .Results Of the 144 strains of K .pneumoniae ,the prevalence of hypermucoviscous phenotype ,K1 , K2 serotypes and rmpA gene was 62 .5% (90/144) ,52 .1% (75/144) and 65 .3% (94/144) ,respectively .The prevalence of K1 ,K2 and rmpA K .pneumoniae strains was 90 .7% (68/75) in K1 ,K2 serotypes .The prevalence of K1 ,K2 isolates and rmpA in hypermucoviscous or non‐hypermucoviscous phenoype was 63 .3% (57/90) ,85 .6% (77/90) and 33 .3% (18/54) , 31 .5% (17/54) ,respectively .The prevalence of serotype K1 ,K2 with or without rmpA gene was 72 .3% (68/94) and 14 .0% (7/50 ) respectively . Of the 42 K . pneumoniae strains isolated from liver abscess ,85 .7% (36/42) were hypermucoviscous phenotype and 88 .1% (37/42 ) were serotypes K1 , K2 . For the strains from other abscess , bacteremia ,community acquried pneumonia (CAP) ,urinary tract infection (UTI) and biliary tract infection ,the prevalence of hypermucoviscous phenotype was 81 .3% (13/16) ,40 .5%(15/37) ,85 .7% (12/14) ,52 .4% (11/21) and 21 .4% (3/14) ,respectively ,and the prevalence of serotypes K1 ,K2 was 56 .3% (9/16) ,29 .7% (11/37) ,64 .3% (9/14) ,38 .1% (8/21) and 7 .1% (1/14) ,respectively .K1 serotype isolate accounted for 61 .9% of the strains from liver abscess .The ratio between serotype K1 and K2 was similar in the isolates from other abscess ,CAP ,UTI or bacteremia .Non‐K1 ,K2 serotype isolates were common in biliary tract infection .The prevalence of extended‐spectrum beta‐lactamases (ESBLs ) was 5 .5% in hypermucoviscous phenotypes and 33 .3% in the non‐hypermucoviscous phenotypes .Conclusions rmpA gene is associated with the hypermucoviscous phenotype of K .pneumoniae strains and commonly identified in K1 ,K2 serotype isolates .Serotypes K1 ,K2 isolates are important pathogens in liver abscess and CAP ,and also common in other abscess ,UTI and bacteremia .K1 serotype isolate was most common in liver abscess .The prevalence of K1 or K2 serotype was similar in other infections . The prevalence of ESBLs is lower in hypermucoviscous strains than in non‐hypermucoviscous strains and is associated with lower resistance rate to most of the antibiotics tested .
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Objective To investigate the prevalence and the transmission of oqxAB gene in clinical strains of Escherichia coli and Klebsiella pneumoniae .Methods Nonduplicate clinical isolates of E.coli (n=72)and K .pneumoniae (n=49)were col-lected.The oqxAB gene was amplified by PCR.The product was sequenced.Plasmid conjugation experiments were done in oqxAB-positive E.coli and K.pneumoniae strains to detemine whether oqxAB gene is located in plasmid.The MICs and mu-tant prevention concentrations (MPCs)for ciprofloxacin were determined in transconjugants with oqxAB gene by agar dilution method.Results The oqxA,oqxB and oqxAB were identified in 15,4,and 7 of the 72 strains of Escherichia coli and 4,1,and 34 of the 49 strains of K.pneumoniae,respectively.The oqxAB gene was positive in 2 (2/16)ciprofloxacin sensitive and 5 (5/56)ciprofloxacin resistant E.coli strains,in 8 (8/14)ciprofloxacin sensitive and 26 (26/35)ciprofloxacin resistant K. pneumoniae strains,respectively.The E.coli and K.pneumoniae strains with or without oqxAB did not show different sus-ceptibility to ciprofloxacin.The oqxA and oqxB sequences from E.coli and K.pneumoniae showed 99% similarity to the se-quences of GeneBank accession number AB601773.1 and accession number FJ975561.1,respectively.The oqxAB gene was successfully transferred in 4 of the 5 oqxAB-positive E.coli strains.The MIC of ciprofloxacin was 0.25-0.5 mg/L against the transconjugants,31-62 times higher than the MICs for the recipient strains.The MPC of ciprofloxacin was 8-16 mg/L against the transconjugants,32 times higher than that for recipient strain J53.The oqxAB gene were not transferred in K. pneumoniae. When the MIC of ciprofloxacin was ≤0.062 5 mg/L,the MPC of ciprofloxacin was 0.25-0.5 mg/L for K.pneumoniae strains with or without oqxAB.When MIC was 0.25-0.5 mg/L,the MPC of ciprofloxacin was 2-16 mg/L for K .pneumoniae strains with or without oqxAB .Conclusions oqxAB gene is present in E .coli and K .pneumoni-ae .The oqxAB gene spreads through plasmid in E .coli.The nonsiginificant difference of oqxAB prevalence between ciproflox-acin sensitive and ciprofloxacin resistant strains indicates that oqxAB gene may mediate low level resistance to ciprofloxacin in E.coli.The E.coli transconjugants of oqxAB gene can produce high level resistance under the selection pressure of ciproflox-acin.The high level resistance in K .pneumoniae under selection pressure of ciprofloxacin is not associated with oqxAB gene, but related to the ciprofloxacin MIC against these strains.
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Objective To investigate the prevalence of 16S rRNA methylase genes, armA and rmtB, which mediate high level aminoglycoside resistance, in gram-negative bacteria isolated from 2 hospitals in Dalian and study the mechanism of aminoglycoside resistance.Methods A total of 134 amikacin-resistant clinical isolates of gram-negative bacteria were collected. Two 16S rRNA methylase genes, armA and rmtB, were identified by PCR-based assays. PCR products were extracted for DNA sequencing analysis. armA and rmtB gene mapping were conducted by plasmid extraction, conjugation and transformation. The MICs of amikacin, gentamicin and tobramycin were determined for the positive isolates, transconjugants and the resultant strain of transformation using agar dilution technique. Results Overall armA was identified in 21 strains of Acinetobacter baumannii, rmtB in 5 strains of Escherichia coli and 5 strains of Klebsiella pneumoniae. Plasmid extraction and conjugation experiments were only successful for rmtB-positive isolates. Transconjugant and DH5a (pMDarmA) exhibited high-level resistance to aminoglycosides.Conclusions The 16S rRNA methylase genes, armA and rmtB are identified in Dalian. armA gene is identified in A. baumannii. rmtB gene is located on the plasmid of E. coli and K. pneumoniae. armA and rmtB can induce high-level resistance to aminoglycosides.