Association between Antibiotic Exposure and the Risk of Rash in Children with Infectious Mononucleosis: a Multicenter, Retrospective Cohort Study.

Present evidence suggests that the administration of antibiotics, particularly aminopenicillins, may increase the risk of rash in children with infectious mononucleosis (IM). This retrospective, multicenter cohort study of children with IM was conducted to explore the association between antibiotic exposure in IM children and the risk of rash. A robust error generalized linear regression was performed to address the potential cluster effect, as well as confounding factors such as age and sex. A total of 767 children (aged from 0 to 18 years) with IM from 14 hospitals in Guizhou Province were included in the final analysis. The regression analysis implied that exposure to antibiotics was associated with a significantly increased incidence of overall rash in IM children (adjusted odds ratio [AOR], 1.47; 95% confidence interval [CI], ~1.04 to 2.08; P = 0.029). Of 92 overall rash cases, 43 were probably related to antibiotic exposure: two cases (4.08%) in the amoxicillin-treated group and 41 (8.15%) in the group treated with other antibiotics. Regression analysis indicated that the risk of rash induced by amoxicillin in IM children was similar to that induced by other penicillins (AOR, 1.12; 95% CI, ~0.13 to 9.67), cephalosporins (AOR, 2.45; 95% CI, ~0.43 to 14.02), or macrolides (AOR, 0.91; 95% CI, ~0.15 to 5.43). Antibiotic exposure may be associated with an increased risk of overall rash in IM children, but amoxicillin was not found to be associated with any increased risk of rash during IM compared to other antibiotics. We suggest that clinicians be vigilant against the occurrence of rash in IM children receiving antibiotic therapy, rather than indiscriminately avoiding prescribing amoxicillin.

Cloning, expression and antiviral activity of mink alpha-interferons.

BACKGROUND: As a key link between innate and adaptive immune responses, the interferon (IFN) system is the first line of defense against viral infection. IFN, and in particular, IFN-α, has been used clinically as an effective therapeutic agent for viral infections. However, different subtypes of IFN-α demonstrate distinct antiviral activity. Therefore, it is important to identify IFN-α subtypes with high antiviral activity for the development of genetically engineered antiviral drugs. RESULTS: In this study, we cloned the genes for 13 IFN-α subtypes from peripheral blood lymphocytes of the mink. The homologies of the 13 mink IFN-α genes were 93.6-99.3% and 88.8-98.4% at the nucleotide and amino acid sequence levels, respectively. In contrast to human and canine IFN-α subtypes, most mink IFN-α subtypes contained two N-glycosylation sites. We expressed and purified 13 mink IFN-α subtypes in Escherichia coli. The cytopathic effect inhibition assay showed that all the 13 recombinant mink IFN-α subtypes inhibited the propagation of vesicular stomatitis virus in WISH cells, with IFN-α2 and IFN-α12 demonstrating the highest activities. Furthermore, recombinant mink IFN-α2 and IFN-α12 significantly suppressed the propagation of canine distemper virus in Vero cells, with IFN-α2 demonstrating the highest activity. CONCLUSIONS: We identified the mink IFN-α2 subtype as a promising candidate for the development of effective antiviral drugs.

[Establishment and application of a Vero cell line stably expressing raccoon dog SLAM, the cellular receptor of canine distemper virus].

OBJECTIVE: The signaling lymphocyte activation molecule (SLAM, also known as CD150), is used as a cellular receptor by canine distemper virus (CDV). Wild-type strains of CDVs can be isolated and propagated efficiently in non-lymphoid cells expressing this protein. Our aim is to establish a Vero cells expressing raccoon dog SLAM (rSLAM) to efficiently isolate CDV from pathological samples. METHODS: A eukaryotic expression plasmid, pIRES2-EGFP-rSLAMhis, containing rSLAM gene fused with six histidine-coding sequence, EGFP gene, and neomycin resistance gene was constructed. After transfection with the plasmid, a stable cell line, Vero-rSLAM, was screened from Vero cells with the identification of EGFP reporter and G418 resistance. Three CD positive specimens from infected foxes and raccoon dogs were inoculated to Vero-rSLAM cells for CDV isolation. Foxes and raccoon dogs were inoculated subcutaneously LN (10)fl strain with 4 x 10(2.39)TCID50 dose to evaluate pathogenicity of CDV isolations. RESULTS: The rSLAMh fused gene was shown to transcript and express stably in Vero-rSLAM cells by RT-PCR and Immunohistochemistry assay. Three CDV strains were isolated successfully in Vero-rSLAM cells 36 -48 hours after inoculation with spleen or lung specimens from foxes and raccoon dogs with distemper. By contrast, no CDV was recovered from those CD positive specimens when Vero cells were used for virus isolation. Infected foxes and raccoon dogs with LN(10)f1 strain all showed typical CD symptoms and high mortality (2/3 for foxes and 3/3 for raccoon dogs) in 22 days post challenge. CONCLUSION: Our results indicate that Vero-rSLAM cells stably expressing raccoon dog SLAM are highly sensitive to CDV in clinical specimens and the CDV isolation can maintain high virulence to its host animals.

Differentiation of canine distemper virus isolates in fur animals from various vaccine strains by reverse transcription-polymerase chain reaction-restriction fragment length polymorphism according to phylogenetic relations in china.

In order to effectively identify the vaccine and field strains of Canine distemper virus (CDV), a new differential diagnostic test has been developed based on reverse transcription-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP). We selected an 829 bp fragment of the nucleoprotein (N) gene of CDV. By RFLP analysis using BamHI, field isolates were distinguishable from the vaccine strains. Two fragments were obtained from the vaccine strains by RT-PCR-RFLP analysis while three were observed in the field strains. An 829 nucleotide region of the CDV N gene was analyzed in 19 CDV field strains isolated from minks, raccoon dogs and foxes in China between 2005 and 2007. The results suggest this method is precise, accurate and efficient. It was also determined that three different genotypes exist in CDV field strains in fur animal herds of the north of China, most of which belong to Asian type. Mutated field strains, JSY06-R1, JSY06-R2 and JDH07-F1 also exist in Northern China, but are most closely related to the standard virulent strain A75/17, designated in Arctic and America-2 genetype in the present study, respectively.

Phylogenetic analysis of the haemagglutinin gene of canine distemper virus strains detected from breeding foxes, raccoon dogs and minks in China.

Canine distemper virus (CDV) infects a variety of carnivores, including wild and domestic Canidae. Genetic/antigenic heterogeneity has been observed among the various CDV strains, notably in the haemagglutinin (H) gene, that appears as a good target to gather epidemiological information. Based on sequence analysis of the H gene, wild-type CDV strains cluster into distinct geographic lineages (genotypes), irrespective of the species of isolation. The sequence of the H gene of 28 CDV strains detected from both vaccinated and non-vaccinated breeding foxes, raccoon dogs and minks from different geographical areas of China during the years 2004-2008 was determined. All the CDV strains but two (strains HL and HLJ2) were characterized as Asia-1 genotype and were highly similar to each other (96.2-99.7% at the amino acid [aa] level) and to other Asia-1 strains (96.1-99.5% aa) previously detected in China. The CDV strains HL and HLJ2 were both collected from foxes in Heilongjiang province in 2005. Strain HL resembled CDVs of the Arctic genotype (GR88-like) and displayed high aa identity (98.0%) to the Chinese canine strain Liu. By converse, strain HLJ2 was barely related to CDVs of the Asia-2 genotype (88.7-90.3% aa identity), and could represent a novel CDV genotype, tentatively proposed as Asia-3. These results suggest that at least three different CDV genotypes, distantly related (81.8-91.6% aa identity) to the vaccine strains, Onderstepoort-like (America-1 genotype), are currently circulating in breeding foxes, raccoon dogs and minks in China, and that the genotype Asia-1 is predominant. Whether the diversity between wild-type CDVs and the vaccine strains may affect, to some extent, the efficacy of the vaccines deserves further investigations.

[Cloning, expression and antiviral activity of arctic fox (Alopex lagopus) interferon-gamma gene].

In order to characterize the biological activity of fox (Vulpes vulpes) interferon gamma(VuIFN-gamma), We have isolated the cDNA encoding arctic fox (Alopex lagopus) VuIFN-gamma. This cDNA encodes a 23 amino acid signal peptide and a 144 amino acid mature protein, which shares 99.8% or 99.4% for nucleotide identity with silver fox and canine, respectively, and 100% for amino acid identity. Expression of recombinant mature arctic fox interferon gamma (mVuIFN-gamma) in bacterial system was confirmed by SDS-PAGE and Western blotting analysis. Recombinant VuIFN-gamma showed higher antiviral activity against vesicular stomatitis virus in cultured Vero and MDCK by inhibiting virus induced cytopathic effect, In view of the immunomodulatory and antiviral activities of VuIFN-gamma, it may provide a basis for further research on antiviral therapy of recombinant VuIFN-gamma in economic animal practice.