ABSTRACT
Varicella zoster virus (VZV), a human neurotropic alphaherpesvirus, becomes latent after primary infection and reactivates to produce zoster. To study VZV latency and reactivation, human trigeminal ganglia removed within 24 h after death were mechanically dissociated, randomly distributed into six-well tissue culture plates and incubated with reagents to inactivate nerve growth factor (NGF) or phosphoinositide 3-kinase (PI3-kinase) pathways. At 5 days, VZV DNA increased in control and PI3-kinase inhibitor-treated cultures to the same extent, but was significantly more abundant in anti-NGF-treated cultures (p = 0.001). Overall, VZV DNA replication is regulated in part by an NGF pathway that is PI3-kinase-independent.
Subject(s)
DNA Replication , DNA, Viral/genetics , Herpesvirus 3, Human/genetics , Nerve Growth Factor/genetics , Phosphatidylinositol 3-Kinases/genetics , Virus Activation , Virus Replication , Adult , Aged , Antibodies, Neutralizing/pharmacology , Autopsy , DNA, Viral/biosynthesis , Gene Expression Regulation , Herpes Zoster/genetics , Herpes Zoster/metabolism , Herpes Zoster/pathology , Herpes Zoster/virology , Herpesvirus 3, Human/metabolism , Herpesvirus 3, Human/pathogenicity , Host-Pathogen Interactions , Humans , Male , Middle Aged , Nerve Growth Factor/antagonists & inhibitors , Nerve Growth Factor/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Phosphoinositide-3 Kinase Inhibitors , Protein Kinase Inhibitors/pharmacology , Signal Transduction , Tissue Culture Techniques , Trigeminal Ganglion/drug effects , Trigeminal Ganglion/virology , Virus LatencySubject(s)
Eye Infections, Viral/virology , Herpes Zoster Ophthalmicus/virology , Herpesvirus 3, Human/isolation & purification , Optic Neuropathy, Ischemic/virology , Aged , Aged, 80 and over , Antigens, Viral/analysis , Antiviral Agents/therapeutic use , Eye Infections, Viral/diagnosis , Eye Infections, Viral/drug therapy , Female , Herpes Zoster Ophthalmicus/diagnosis , Herpes Zoster Ophthalmicus/drug therapy , Herpesvirus 3, Human/immunology , Humans , Male , Middle Aged , Optic Neuropathy, Ischemic/diagnosis , Optic Neuropathy, Ischemic/drug therapy , Visual AcuityABSTRACT
Three cohorts of juvenile and subadult Chinook salmon Oncorhynchus tshawytscha received multiple treatments with macrolide antibiotics for bacterial kidney disease (BKD) during rearing in a captive broodstock program. A total of 77 mortalities among the cohorts were screened for Renibacterium salmoninarum, the etiologic agent of BKD, by agar culture from kidney, and isolates from 7 fish were suitable for growth testing in the presence of macrolide antibiotics. The minimum inhibitory concentration (MIC) of erythromycin and azithromycin was determined by a modification of the standardized broth assay using defined medium. The American Type Culture Collection (ATCC) type strain 33209 exhibited a MIC of 0.008 microg m(-1) to either erythromycin or azithromycin. Isolates from 3 fish displayed MICs identical to the MICs for the ATCC type strain 33209. In contrast, isolates from 4 fish exhibited higher MICs, ranging between 0.125 and 0.250 microg ml(-1) for erythromycin and between 0.016 and 0.031 microg ml(-1) for azithromycin. Sequence analysis of the mutational hotspots for macrolide resistance in the 23S rDNA gene and the open reading frames of ribosomal proteins L4 and L22 found identical sequences among all isolates, indicating that the phenotype was not due to mutations associated with the drug-binding site of 23S rRNA. These results are the first report of R. salmoninarum with reduced susceptibility to macrolide antibiotics isolated from fish receiving multiple antibiotic treatments.
Subject(s)
Actinomycetales Infections/veterinary , Anti-Bacterial Agents/pharmacology , Fish Diseases/microbiology , Kidney Diseases/veterinary , Macrolides/pharmacology , Micrococcaceae/drug effects , Salmon/microbiology , Actinomycetales Infections/microbiology , Animals , Azithromycin/pharmacology , Colony Count, Microbial , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Dose-Response Relationship, Drug , Erythromycin/pharmacology , Kidney/microbiology , Kidney/pathology , Kidney Diseases/microbiology , Microbial Sensitivity Tests/veterinary , Micrococcaceae/growth & development , Mutation , Open Reading Frames , RNA, Ribosomal, 23S/chemistry , RNA, Ribosomal, 23S/geneticsABSTRACT
OBJECTIVES: The aim of this study was to characterize a novel conjugative transposon Tn6009 composed of a Tn916 linked to a Staphylococcus aureus mer operon in representative Gram-positive and Gram-negative bacteria isolated in Nigeria and Portugal. METHODS: Eighty-three Gram-positive and 34 Gram-negative bacteria were screened for the presence of the Tn6009 using DNA-DNA hybridization, PCR, hybridization of PCR products, sequencing and mating experiments by established procedures. RESULTS: Forty-three oral and 23 urine Gram-negative and Gram-positive isolates carried the Tn6009. Sequencing was performed to verify the direct linkage between the mer resistance genes and the tet(M) gene. A Nigerian Klebsiella pneumoniae, isolated from a urinary tract infection patient, and one commensal isolate from each of the other Tn6009-positive genera, Serratia liquefaciens, Pseudomonas sp., Enterococcus sp. and Streptococcus sp. isolated from the oral and urine samples of healthy Portuguese children, were able to act as donors and conjugally transfer the Tn6009 to the Enterococcus faecalis JH2-2 recipient, resulting in tetracycline- and mercury-resistant E. faecalis transconjugants. CONCLUSIONS: This study reports a novel non-composite conjugative transposon Tn6009 containing a Tn916 element linked to an S. aureus mer operon carrying genes coding for inorganic mercury resistance (merA), an organic mercury resistance (merB), a regulatory protein (merR) and a mercury transporter (merT). This transposon was identified in 66 isolates from two Gram-positive and three Gram-negative genera and is the first transposon in the Tn916 family to carry the Gram-positive mer genes directly linked to the tet(M) gene.
