The nose and throat are sites commonly used to obtain swab specimens to diagnose upper respiratory tract infections, and some studies have shown differences between the diagnostic accuracies of nose and throat swabs for upper respiratory infections. However, current sampling methods for the diagnosis of upper respiratory tract infections do not differentiate between nose and throat samples. The present study was undertaken to devise a means of determining whether samples were obtained from the nose or throat.Microbiome abundance data of 576 upper respiratory swab samples were obtained from the human microbiome project website. Predictive models were generated to determine sampling sites based on microbiomes using the random forest and regression tree with recursive partitioning methods. The final prediction model showed a near-perfect prediction for sampling sites using only the abundances of Staphylococcaceae and Streptococcaceae. The devised model can be used to predict sampling sites for upper respiratory specimens.

Tuberculosis (TB), a global and deadly infectious disease caused by Mycobacterium tuberculosis (Mtb), is manifested with host immune reaction. The balanced regulation between protective immune and pathologic inflammatory responses is critical to control progression to TB. Chemokines are a large family of cytokines that play an essential role for chemotaxis of immune and inflammatory cells to the sites of infection. Numerous chemokines including CXCL10 were reported as potential biomarkers of various stages of TB infection. In addition, several chemokines and their receptors play as key players to coordinate host immune defense as innate effectors and mediators of adaptive immune responses.Accumulating evidence suggests that some chemokines, if uncontrolled, are associated with host pathological inflammation during infection. In this review, we will discuss recent advances in understanding which chemokines have potentials as diagnostic markers. In addition, we focus the roles and mechanisms by which chemokines and their receptors are involved in both host immune protection and pathology during TB infection. The controlled activation of chemokine system will determine the coordinated biological outcomes of innate immune responses during pathogenic infection.

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), remains one of the most important infectious diseases worldwide. Mtb and its culture filtrates or sonic extracts induce apoptosis in macrophages. However, there is a little known about Mtb components that modulate apoptosis and their regulating mechanism. We identified Rv0753c protein with apoptotic potential through searching the biologic active proteins from the multidimensional fractions of Mtb culture filtrate. Here, we investigated the apoptotic effects of Rv0753c on RAW264.7 cells. The recombinant Rv0753c induced RAW264.7 cells apoptosis in a caspase-9-dependent manner. Dissipation of the mitochondrial transmembrane potential (ΔΨ m ), mitochondrial translocation of Bax, and release of cytochrome c from mitochondria were observed in macrophages treated with Rv0753c. Enhanced reactive oxygen species (ROS) production was required for Rv0753c-mediated apoptosis. Furthermore, ROS-mediated JNK activation was major signaling pathway for Rv0753c-induced apoptosis. Moreover, Rv0753c-mediated apoptosis is dependent on TLR4. Altogether, these results suggest that Rv0753c induce apoptosis through ROS-JNK signaling pathway in RAW264.7 cells.

Tuberculosis (TB) is an old disease caused by Mycobacterium tuberculosis. Although it has been known for humans for thousands of years, the treatment of this disease still requires a lengthy therapy with multiple antibiotics. Also, the emergence of multidrug-resistant strains made it more difficult to treat TB, calling for a novel treatment approach. In Photodynamic therapy (PDT), a photosensitizer, such as methylene blue (MB), is irradiated by a laser, generating reactive oxygen species and killing microorganisms. Here, using M. smegmatis as a model mycobacterium, we examined the utility of PDT in TB treatment. The photosensitizer MB alone showed weak antimicrobial activity; however, when irradiated by a laser, it efficiently killed M. smegmatis (> 97% killing with 30 mg/ml MB and 54 J/cm2 irradiation). Surprisingly, PDT showed more efficient killing activity toward drug-resistant strains of M. smegmatis than the drug-sensitive wild-type strain. In PDT, when the irradiation step alone (Intermittent PDT) or the entire PDT process was repeated (Repeated PDT), the bactericidal activity was significantly enhanced. Since PDT can be applied locally in a short period of time and kills mycobacterium irrespective of its antibiotic resistance status, we conclude that PDT can be a viable option for TB treatment.

The threat of antibiotic resistance is an influencing factor in deteriorating public health. Therefore, new antibiotic development is necessary for continued successful treatment of infectious diseases. Cefiderocol is the first licensed injectable siderophore cephalosporin that chemically conjugates a siderophore and cephalosporin.Due to its high stability against various β-lactamases, it is widely used as an effective antibiotic for multidrug-resistant (MDR) gram-negative microorganisms, including Acinetobacter baumannii, Stenotrophomonas maltophilia, Pseudomonas aeruginosa, and Enterobacteriaceae. Cefiderocol blocks microbial cell membrane synthesis. The binding site of cefiderocol is a penicillin-binding protein. Because of its siderophore-like properties, cefiderocol penetrates gram-negative bacterial periplasmic spaces, increasing its stability against β-lactamases. Unlike earlier cephalosporins, the siderophore of the cefiderocol moiety at position C-3 chelates with iron (ferric form) in the host and is then actively transported into the bacterial periplasmic space. This approach is known as a “Trojan horse” and improves cefiderocol stability against efflux pumps as well as porin channel mutations. Modification at the C-3 and C-7 side-chains produces powerful antibacterial properties against MDR gram-negative bacteria. The U.S. Food and Drug Administration (FDA) approved it as a new treatment option for adult patients with complicated urinary tract infection (cUTI) who have limited and no treatment options. Based on these observations, we conclude that cefiderocol is a potent treatment option for prospective bacterial infections. In this review, we summarize the future prospective use of cefiderocol for bacterial infections.

A semi-replication-competent retroviral (s-RCR) vector system in which the gag-pol and env (GALV FMG, gibbon ape leukemia virus fusogenic membrane glycoprotein) genes were split into two separate packageable vectors was developed. These vectors are more efficient than replication-defective retroviral (RDR) vectors in gene delivery and have a higher transgene capacity than replication-competent retroviral (RCR) vectors. For thegag-pol vector construction, internal ribosomal entry site-enhanced green fluorescent protein (IRES-EGFP) was introduced downstream of the gag-pol sequence of the previously constructed MoMLV-10A1-EGFP vector to generate MoMLV-gag-pol-IRES-EGFP. For env vector construction, GALV FMG was inserted into the pCLXSN vector to generate pCLXSN-GALV FMG-IRES-EGFP.MoMLV-gag-pol-IRES-EGFP and pCLXSN-GALV FMG-IRES-EGFP were co-transfected into 293T cells to generate s-RCR viruses. These viruses propagated EGFP and induced syncytium formation due to the cytotoxicity of GALV FMG. To improve the cytotoxicity of s-RCR vector system, GALV FMG or the fusogenic envelope G glycoprotein of the vesicular stomatitis virus (VSV-G) was inserted into gag-pol vector. Co-transfection of MoMLV-gag-pol-IRES-GALV FMG + MoMLV-EGFP or MoMLV-VSV-G + pCLXSN-GALV FMG-IRES-EGFP in 293T cells induced stronger syncytium formation than s-RCR vectors (MoMLV-gag-pol-IRES-EGFP + pCLXSN-GALV FMG-IRES-EGFP). In addition, s-RCR stocks collected from transfected 293T cells induced syncytium formation in the human cancer cell lines HT1080 and TE671.Hence, the s-RCR vector systems developed in this study are useful tools for cancer gene therapy.

Feline herpesvirus type 1 (FHV-1) causes respiratory and ocular disease in cats.Although isolates of FHV-1 circulating in cats have been reported worldwide, Korean FHV-1 isolates and their features have not been reported thus far. We aimed to investigate the biological and molecular characterization of two FHV-1 isolates based on the nucleotide sequence of thymidine kinase (TK) and glycoprotein B (gB) gene. In total, 48 samples from 12 cats were prepared for virus isolation.For the diagnosis, virus isolation, indirect fluorescence assay (IFA), electron microscopy (EM), and polymerase chain reaction (PCR) and for the molecular characterization, cloning and sequencing were used. Based on many methods such as virus isolation with specific cytopathic effects, IFA, EM, and PCR, two isolates were confirmed as FHV-1 and they showed the highest viral titer (108.3 to 108.5 TCID50 /mL) in the Crandell–Rees Feline Kidney cells at 48 h after inoculation, but did not grow in MDCK and Vero cells. The nucleotide and amino acid sequences of the full TK and gB gene of FHV191071 and FHV191072 isolates were determined and compared with those of other herpesvirus strains. Two isolates possessed the same nucleotide sequences belonging to FHV-1 group and had the highest similarity (99.9%) with the KANS-02 strain, which was isolated from shelter in USA in 2016. Two isolates were confirmed as FHV-1 and they will be a useful basic resource for evaluating current FHV-1 vaccine and developing diagnostic tools.

Gram-negative bacterial pathogens produce outer membrane vesicles (OMVs) and this secreted cargo plays a role in host-pathogen interactions. OMVs isolated from Burkholderia cepacia induce the cytotoxicity and pro-inflammatory responses both in vitro and in vivo, but OMV components associated with host pathology have not been characterized. This study analyzed the proteomes of OMVs produced by B. cepacia ATCC 25416 and investigated whether proteins in B. cepacia OMVs were responsible for host pathology in vitro. Proteomic analysis revealed that a total of 265 proteins were identified in B. cepacia OMVs. Of the 265 OMV proteins, 179 (67.5%), 32 (12.1%), 27 (10.2%), 17 (6.4%), and 10 (3.8%) were predicted to be located in the cytoplasm, inner membrane, periplasmic space, outer membrane, and extracellular compartment, respectively. Several putative virulence factors were also identified in B. cepacia OMVs. B. cepacia OMVs slightly induced the cytotoxicity in lung epithelial A549 cells, but there was no difference in cytotoxic activity between intact OMVs and proteinase K-treated OMVs. B. cepacia OMVs stimulated the expression of pro-inflammatory cytokine and chemokine genes in A549 cells, but the expression of these cytokine genes was significantly inhibited in A549 cells incubated with proteinase K-treated OMVs. In conclusion, our results suggest that proteins in B. cepaciaOMVs are directly responsible for pro-inflammatory responses in lung epithelial cells.

Varicella-zoster virus (VZV) is a causative agent for chickenpox in primary infection and shingles after reactivation from latency. Both varicella and zoster can be prevented by live attenuated vaccines, but the molecular mechanism of attenuation is not clearly understood. In this study, the genome sequences of three varicella vaccine strains were analyzed for the genetic diversity including single nucleotide polymorphism (SNP) and genetic polymorphism. A total of 38 SNPs were identified including 29 substitutions and 9 insertion/deletions. The number of genetically polymorphic sites (GPS) was highest in Varivax and lowest in Varilrix. GPS in the R region including R1, R2, and R3 appeared to be responsible for the genetic polymorphisms in the open reading frame (ORF) 11, 14, and 22 in all three vaccine strains. A relatively large number of GPS were observed in ORF31, 55, and 62, which are known to be essential for virus replication, suggesting that the attenuation of the vaccine strains may be attributed by the diversity of these genes.

The rapid diagnosis of canine distemper virus (CDV) helps to determine the treatment of dogs in veterinary clinics. We evaluated the performance of seven commercial rapid immunochromatographic test (RICT) kits for the detection of CDV. Six core dog viral pathogens (canine adenovirus type 1 and 2, canine coronavirus, canine parainfluenza virus, canine parvovirus, and rabies virus), five CDV strains (CD1901, Lederle, Rockborn, Onderstepoort, and Synder Hill), and three bacteria (Bordetella bronchiseptica, Leptospira canicola, and Staphylococus aureus) were used to determine the cross-reactivity and detection limits of the kits. The seven commercial RICT kits did not yield positive results with the six dog viruses or the three bacteria. All the RICT kits for CDV detected the Korean CDV isolate. The detection limits of the RICT kits for the Korean CDV isolate, CD1901, belonging to Asia 1 genotype ranged from 103.0 to 104.0 TCID50/mL. There was an average difference of 1.1 in scores judged by eye between four CDV vaccine strains and CD1901 strain. Therefore, the RICT kits enable the detection of CDV vaccine strains, but need to be improved to detect CDV circulating in dog populations in Korea.