Genomic Analysis of an Escherichia coli Sequence Type 167 Isolate Harboring a Multidrug-Resistant Conjugative Plasmid, Suggesting the Potential Transmission of the Type Strains from Animals to Humans.

Purpose: The E. coli ST167 clone is the globally dominant ST among extraintestinal pathogenic E. coli (ExPEC) and is frequently associated with carbapenem resistance. This study reports genomic characterization of a pandrug-resistant E. coli ST167 isolate (ECO3183) and the possibility of the type strains' transmission. Materials and Methods: Antibiotic susceptibility testing was performed using disk diffusion and the VITEK 2 automated system. The E. coli ECO3183 genome was sequenced. We used the genome to analyze the phylogenetic relationship, phylogenetic group, sequence type (ST), acquired antibiotic resistance genes (ARGs), IS elements, genomics islands, the replicon type and transferability of the plasmids. The conjugative transfer of plasmids was assessed using filter mating experiments. Results: ECO3183 contained a 4.87-Mb chromosome and two plasmids [pECO3183-1 (167.63 Kb) and pECO3183-2 (46.16 Kb)]. It belonged to phylogenetic group A, clonal complex 10 (CC10), and ST167. ECO3183 is a pandrug-resistant strain nonsusceptible to 24 tested antimicrobials representing 8 different antimicrobial classes. Among 55 E. coli isolates phylogenetically related to ECO3183, 47% (26/55) were from humans, while 35% (19/55) were from animals. Further analysis revealed that among 1140 ST167 isolates (in the EnteroBase database), 4% (47/1140) originated from environments, 17% (192/1140) were isolated from humans, and 78% (890/1140) were obtained from animals. The pECO3183-1 contained two identical repeats of a 9633 bp region (IS6100-sul1-ΔaadA16-dfrA27-arr-3-aac(6')-Ib-cr-IS26) and a 17.88-kb resistance island (sul2-aph(3″)-Ib-aph(6)-Id-IS26-Δaph(3')-Ia-IS26-tet(A)-ΔfloR-ΔISVsa3-IS26-Δaac(3)-IId-IS26-mph(A)), and these three regions contained most of ECO3183 carrying ARGs. It was identified as a conjugative plasmid, which confers MDR resistance and has the potential to spread. Conclusion: ECO3183 exhibited pandrug-resistance phenotype that was mediated by pECO3183-1 carrying MDR ARGs and pECO3183-2 carrying blaNDM-5. Source analysis of strains indicated that ST167 E. coli might be transmitted between species from animals to humans, which needs continued monitoring.

Construction and preliminary investigation of a plasmid containing a novel immunotoxin DT390-IL-18 gene for the prevention of murine experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is a neuropathological animal model for multiple sclerosis. Antigen-presenting cells (APCs) expressing interleukin-18 receptor (IL-18R) were shown to be crucial in the beginning and progress of EAE. In this study we tested the effect of a novel recombinant immunotoxin targeting IL-18R-bearing APC for EAE prevention. The novel eukaryotic plasmid DT390-IL-18-SRalpha, encoding recombinant immunotoxin DT390-IL-18, was constructed. The immunotoxin consisted of IL-18 as the targeting moiety, and a truncated diphtheria toxin (DT) as the toxic moiety. Transfection assay and proliferation inhibition assay proved the immunotoxin could be expressed in vitro and was toxic to the activated mouse T cells. To evaluate the preventive effect of DT390-IL-18-SRalpha on EAE in vivo, cationic liposome-embedded DT390-IL-18-SRalpha was injected into the hind limbs of EAE mice. DT390-IL-18-SRalpha-treated mice showed a delayed manifestation of EAE and decreased symptoms compared to the mice treated with plasmid DT390-SRalpha or phosphate-buffered saline alone. A significant reduction in infiltrating inflammatory cells was detected in the brain tissues from immunotoxin-treated mice as compared with the controls by hematoxylin-eosin staining. This study suggested that the recombinant immunotoxin DT390-IL-18 could be expressed in vitro and in vivo, and prevented murine EAE effectively.

[Study on genetic polymorphisms of P-selectins in Chinese Han of Chengdu and Thai populations].

OBJECTIVE: To study the gene polymorphisms of position --2123 C/G,--1969 G/A,--1817 T/C in promoter region and of Thr715Pro in exon thirteenth of P-selectin in the Chinese Han of Chengdu and Thai populations, and simultaneously to compare distributions of genotype and allelic frequencies of P-selectins among different races. Methods The genotypes and allele frequencies of the P-selectin base --2123 C/G,--1969 G/A,-1817 T/C and amino acid Thr715Pro were detected by polymerase chain reaction -restriction fragment length polymorphism (PCR-RFLP) to 120 healthy Chinese Han of Chengdu and 110 Thai population. RESULTS: There were no significant differences in the genotype and allele distribution of--2123 C/G,--1969 G/A,--1817 T/C polymorphisms for the P-selectin gene between Chinese Han of Chengdu and Thai populations (P > 0.05), in which compared with England and American, the distribution of P-selectin genotype and allele had significantly differences among ethnics (P < 0.001). No polymorphism of Thr715Pro was found in this study. Conclusion In Chinese Han of Chengdu and Thai populations the polymorphisms exist at base position--2123 C/G,--1969 G/A and --1817 T/C in promoter region of P-selectin. There are no significant differences in the genotype and allele distribution of the P-selectin gene polymorphisms between Chinese Han of Chengdu and Thai populations, but significantly different distribution of P-selectin gene polymorphisms occur among ethnics.

Association of transforming growth factor-beta1 gene polymorphisms with genetic susceptibility to nasopharyngeal carcinoma.

BACKGROUND: Nasopharyngeal cancer (NPC) is multifactorial, and the genetic background may be a crucial etiologic factor. Transforming growth factor-beta1 (TGF-beta1) is a multifunctional cytokine, it promotes tumor growth and metastasis in later stages of phase of cancer development. Variations in the DNA sequence in the TGF-beta1 gene may lead to altered TGF-beta1 production and/or activity, and so this can modulate an individual's susceptibility to NPC. To test this hypothesis, we investigated the association of the TGF-beta1 polymorphisms and their haplotypes with the risk of NPC in a Chinese population. METHODS: We analyzed 2 single nucleotide polymorphisms (SNPs) of TGF-beta1 gene promoter -509C/T and 869T/C (Leu10Pro) at exon one in 108 patients with NPC and 120 age- and sex-matched controls in a Chinese population, using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) strategy. RESULTS: There were significant differences in the genotype and allele distribution of -509C/T and 869T/C (Leu10Pro) polymorphisms of the TGF-beta1 gene among cases and controls. The -509T and 869C alleles carriers were associated with a significantly increased risk of NPC as compared with the non-carriers (OR=1.64, 95% CI, 1.13-2.39, P=0.009 and OR=1.70, 95% CI, 1.17-2.46, P=0.006, respectively). Consistent with the results of the genotyping analyses, the -509T/869C haplotype was associated with a significantly increased risk of NPC as compared with the -509C/869T haplotype (OR=1.68; 95% CI, 1.14-2.48; P=0.009). CONCLUSION: TGF-beta1 -509C/T and 869T/C polymorphisms, and their haplotypes are significantly associated with the risk of NPC. Our data suggests that TGF-beta1 -509C/T and 869T/C polymorphisms could be used as genetic susceptibility markers of the NPC.

[Genetic polymorphisms of interferon-gamma and interleukin-8 in patients with nasopharyngeal carcinoma].

OBJECTIVE: To investigate the distribution of genotype and allele frequencies of the genetic polymorphisms of IFN-gamma and IL-8 in patients with nasopharyngeal carcinoma (NPC) and analyze the relationship between the genetic polymorphisms of IFN-gamma and IL-8 and NPC. METHODS: A total of 105 NPC patients and 109 healthy people were recruited in this study. The polymorphism of IL-8-251 locus was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The IFN-gamma CA-repeat polymorphism was determined by polymerase chain reaction and polyacrylamide gel electrophoresis with silver staining. The relationship between the polymorphisms of the two loci and NPC was analyzed. RESULTS: There was no statistically significant difference in IL-8-251(A/T) genotype and allele frequencies between the NPC patients and the healthy people (P < 0.05). The frequency of IFN-gamma 13 times CA repeats in the NPC patients was significantly lower than that of the healthy people (chi2 = 5.878, P = 0.015). A significant difference in the distribution of the genotype of (CA)13+ / (CA)13+, (CA)13+ / (CA)13- and (CA)13- / (CA)13- between the NPC patients and the healthy people was also found (chi2 = 15.181, P = 0.001). CONCLUSION: The IFN-gamma 13 times CA-repeat polymorphism is associated with the onset of NPC. But no association between the polymorphism of IL-8-251 (A/T) locus and NPC is evident. The IFN-gamma CA-repeat polymorphism might play an important role in determining the susceptibility to nasopharyngeal carcinoma.

Prevalence of Ureaplasma urealyticum, Mycoplasma hominis, Chlamydia trachomatis infections, and semen quality in infertile and fertile men in China.

OBJECTIVE: To study the prevalence of ureaplasma urealyticum (UU), mycoplasma hominis (MH), and chlamydia trachomatis (CT) infections among infertile and fertile men and to study the effects of these infections on semen quality. METHODS: A total of 621 infertile and 615 fertile men were enrolled in this study in our hospital between January 2011 and June 2013. Semen samples were obtained by masturbation after 3-5 days of sexual abstinence. Semen analysis was performed using the methods outlined by the World Health Organization. UU and MH were detected using culture, and CT was detected using polymerase chain reaction. RESULTS: There were no significant differences between infertile and fertile men in terms of the prevalences of UU, MH, and CT. The presence of UU was related, in infected compared with uninfected men, to lower mean sperm concentration and lower vitality. The differences in semen parameters associated with MH or CT between infected and uninfected men did not attain statistical significance. CONCLUSION: During the infertility assessment, the clinician should consider evaluating for the presence of UU in men with oligospermia or decreased sperm vitality.