Intervirology最新文献

Background: Staphylococcus aureus is a Gram-positive, pathogenic bacterium that causes a wide range of symptoms in humans and can form biofilm, which is a multicellular community of microorganisms that attaches to nonbiological and biological surfaces.

Methods: Here, we aimed to isolate and characterize an S. aureus phage and examine the bactericidal activity alone and in conjunction with streptomycin treatment.

Results: We isolated a virulent phage, WV, from a slaughterhouse in Jiangsu, China. This strain belonged to the family Myoviridae and presented a genome size of 141,342 bp. The optimal pH of the preservation buffer was 6-7, optimal growth temperature was 37°C, and optimal multiplicity of infection was 0.01. Phage WV can sterilize most clinical strains of S. aureus that had been isolated from clinical patients in the First People's Hospital of the Yunnan Province. Against low-concentration S. aureus culture, streptomycin demonstrated a greater antibiofilm effect than that of phage WV. By contrast, in high-concentration S. aureus culture, phage WV demonstrated greater antibiofilm effect than that of streptomycin. The use of phage WV and streptomycin together had a substantially greater overall antibiofilm effect than that achieved using either component alone.

Conclusion: This study provides strong evidence for the effectiveness of phage application for the reduction of S. aureus biofilm growth and suggests that phages can be considered as a viable alternative to antibiotics in clinical settings.

Introduction: We investigated the prevalence of human metapneumovirus (hMPV) among patients with acute respiratory infections in Bulgaria, and performed genetic characterization of the F gene of these strains.

Methods: Nasopharyngeal swabs collected from patients of a range of ages were tested by using real-time PCR for 12 respiratory viruses. The F gene was sequenced, and phylogenetic and amino acid analyses of the F gene/protein were performed.

Results: A total of 1,842 patients were examined during a 3-year period; 1,229 patients (66.7%) were positive for at least one respiratory virus. hMPV was identified in 83 (4.5%) patient samples. Eleven (13%) of hMPV-positive patients were coinfected with another respiratory virus. The hMPV incidence rate in the 2016/2017, 2017/2018, and 2018/2019 winter seasons was 5.4, 5.4, and 3.1%, respectively. hMPV was mainly detected in specimens collected between January and May (89.2% of cases). The incidence of hMPV infection was highest (5.1%) among the youngest age-group (0-4 years), where hMPV was a causative agent in 8.1 and 4.8% of bronchiolitis and pneumonia cases, respectively. Among the patients aged ≥5 years, hMPV was detected in 2.2 and 3.2% of cases of pneumonia and central nervous system infections, respectively. Phylogenetic analysis of the F gene showed that the sequenced hMPV strains belonged to the A2b, B1, and B2 genotypes. Numerous amino acid substitutions were identified compared with the NL00/1 prototype strain.

Conclusion: This study revealed the significant role of hMPV as a causative agent of serious respiratory illnesses in early childhood, and also demonstrated year-to-year changes in hMPV prevalence and genetic diversity in circulating strains.

Background: Monitoring of hepatitis B virus (HBV) viral load has become an essential phase in the treatment of HBV. There are many commercial assays available for HBV viral load quantification. In this study, we have evaluated the performance characteristics of Amplisure® HBV Kit in comparison with the Qiagen artus HBV QS-RGQ kit for HBV DNA quantitation.

Methods: Comparison of 2 methods was carried out on 200 clinical samples, 150 HBV DNA positive and 50 HBV DNA negative, by a reference method. Results obtained with Amplisure® HBV Kit (Amplisure HBV) were compared using the Qiagen artus HBV QS-RGQ assay results as the comparator method.

Result: The overall performance of the Amplisure HBV compared with the comparator method shows positive and negative clinical agreement of 100 and 76%, respectively. Among the 12 qualitative discrepant samples, all positive with Amplisure HBV were sequenced and 10 were below comparator method's LOD. For 5 weak positives (-0.22 to 0.98 log IU/mL), the sequencing failed. The 7 other positives (0.48 to 1.89 log IU/mL) were confirmed positive by sequencing. Quantitative comparison gave an r2 of 0.967 with a mean log difference of 0.09 log10 IU/mL.

Conclusion: This study shows that Amplisure® HBV Quantitative Kit shows comparable performance with artus HBV QS-RGQ assays and can be useful in management and therapeutic monitoring of HBV in a clinical practice.

Background: Polyomaviruses (PyVs) were initially described in animals. They have also been detected in humans with some evidence that could play a role in skin carcinogenesis.

Objectives: This study aimed to verify the presence of PyVs in different skin tumour samples and to make clinical correlations with patients' epidemiological data from Clinics Hospital of Medical School of University of São Paulo, Brazil.

Methods: This is a cross-sectional study. A random selection was performed of 120 patients with histopathological exams of different cutaneous neoplasms equally divided into 6 groups and 20 patients with normal skin. The available skin specimens were analysed with 2 different techniques of PCR (conventional and real time) for detection of PyV DNA. Concomitantly, retrospective analysis of the respective medical records for the collection of epidemiological data was done. Analyses suitable for categorical data were used to compare the proportion of patients in each group.

Results: PyV DNA was found in 25.69% of the samples: 15% in basal cell carcinoma group, 15% in squamous cell carcinoma, 28.57% in melanoma, 15% in dermatofibrosarcoma protuberans, 13.33% in Kaposi sarcoma, 65% in Merkel cell carcinoma (MCC), and none in normal skin. Merkel cell PyV detection was statistically significant in MCC patients (p value <0.01), but no correlations were found between PyVs and others skin tumours.

Conclusion: This study demonstrated the presence of PyVs in different skin tumours; however, no association of any PyVs found in any skin tumour with epidemiological data could be shown. Further studies are still needed to elucidate the mechanisms of PyVs in skin carcinogenesis.

Introduction: Poliovirus causes paralysis by infecting the nervous system. Currently, 2 types of polio vaccine are given in many countries in polio eradication program including inactivated polio vaccine (IPV) and oral polio vaccine (OPV). Because of OPV-related paralysis, OPV should be replaced by IPV.

Methods: The aim of this study was to prepare the gamma-irradiated IPV and determine its effectiveness compared with the commercial vaccine (OPV) in the mouse model. The virus titration of OPV was determined and then inactivated by the appropriate dose of gamma radiation into an irradiated vaccine formula. The vaccine was inoculated in BALB/c mice in 2 different formulations of intramuscular injection with 2-week intervals. The level of anti-polio-neutralizing antibody and polio-specific splenocyte proliferation assay were evaluated by collecting the blood samples and spleens of the vaccinated groups with conventional vaccine and irradiated vaccine.

Results: There was a significant increase in the neutralizing antibody titration between all of the vaccinated groups and negative control group (A) (p < 0.05). And it shows that the IPV by gamma irradiation has the highest antibody titration. Also, the increasing of stimulation index value in the B* group, F group, and G group was the most against other groups. Furthermore, the neutralizing anti-serum titer and splenic lymphocyte proliferation assay show humoral and cellular immunity were significantly increased in the irradiated vaccine group as compared with conventional group.

Conclusion: According to the results, gamma-irradiated IPV could induce humoral and cellular immunity in vaccinated mouse groups, so the irradiated poliovirus could be recommended as a good candidate vaccine to prevent the transport of poliovirus to the central nervous system and thus protect against paralysis.

Background: Foot-and-mouth disease (FMD) is an infectious and highly contagious disease of cloven-hoofed domestic and wild animals, causing heavy economic losses to the livestock industry. Rapid and reliable diagnosis of the disease is essential for the implementation of effective control measures. This study compared sandwich enzyme-linked immunosorbent assay (S-ELISA) and conventional reverse transcription polymerase chain reaction (RT-PCR) for the diagnosis of FMD.

Methods: A total of 60 epithelial samples from suspected cases of FMD were tested using both S-ELISA and RT-PCR assays. The level of agreement between the assays was assessed by calculating the Kappa value.

Results: S-ELISA detected 38 (63%) samples positive for FMD virus (FMDV). Being predominant, serotype O was detected in 22 (57.9%) of the total samples tested positive, whereas 9 (23.7%) and 7 (18.4%) samples were found positive for serotypes A and Asia-1, respectively. RT-PCR detected viral genome in 51 (85%) of the samples using pan-FMDV primers set, 1F/1R. Thirty-six samples were found positive and 7 negative by both the tests. The level of agreement between the tests was assessed by calculating the Kappa value, which was found to be fair (Kappa value = 0.303 and 95% CI = 0.089; 0.517) and significant (p = 0.009). However, 2 samples, which were found positive on S-ELISA tested negative on RT-PCR. This may be attributed to the presence of nucleotide mismatch(es) in the primer-binding sites that may have resulted in failure of amplification of the viral genome. The serotype-specific RT-PCR assays not only confirmed serotyping results of S-ELISA but were also able to establish serotype in 9 S-ELISA-negative but pan-FMDV RT-PCR-positive samples.

Conclusions: The RT-PCR assay contributes significantly to establishing a quick, sensitive, and definitive diagnosis of FMD in resource-constrained countries. Samples giving negative results in S-ELISA should be tested in RT-PCR for the disease detection and virus typing.

Background: Serum osteopontin (OPN) concentrations were found to be significantly increased in patients infected with hepatitis B virus (HBV) and patients with hepatocellular carcinoma (HCC).

Objective: The aim of this study was to determine the association among HCC, OPN, and HBV.

Methods: Two hundred and forty-one subjects were recruited and divided into 6 groups: healthy controls, asymptomatic HBsAg carriers, HBsAg (-) patients with other tumors, HBsAg (+) chronic liver disease patients, HBsAg (+) patients with HCC, and HBsAg (-) patients with HCC or liver cirrhosis (LC). Serum concentrations of OPN and HBsAg were measured and analyzed.

Results: OPN concentrations in the HBsAg (+) HCC group were significantly higher than the healthy control group and the HBsAg (-) patients with other cancers (both p = 0.0001). The OPN concentrations of the HBsAg (-) patients with HCC or LC also did not differ significantly from those of the healthy control group (p = 0.075). There is a correlation between the titer of HBsAg and concentrations of OPN in all 3 HBsAg (+) groups (all p values <0.05).

Conclusions: Infection with HBV may increase the serum concentrations of OPN. The association of OPN and HCC may be not attributable to tumor development per se but, rather, to HBV infection.

Background: Members of the Polyomaviridae family, BK virus (BKV), and John Cunningham virus (JCV) are linked to polyomavirus-associated nephropathy-associated transplant rejection in immunodeficient patients.

Objective: The aim of the study was to evaluate the prevalence of BKV and JCV in immunocompetent individuals in the north of Iran.

Methods: Ninety-one urine samples were obtained from renal transplant recipients with a mean age of 39.78 ± 11.19 years. A healthy control group of 65 volunteers with an average age of 40.32 ± 10.7 years also contributed. After DNA extraction, positive cases were detected through PCR. Genotyping was done by alignment and phylogenetic tree construction of the VP1 region against all known JCV and BKV genotypes.

Results: The prevalence of BKV and JCV was 15.38 and 19.78%, respectively. JCV was detected in 7.69% of the control group. The prevalence of the BKV between the case and control groups was significant (p < 0.0001). There was no significant association between BKV and JCV and duration of dialysis (p > 0.05). Overall, 62.16% of JCV cases were genotype I. Besides, genotype II was dominant within patients with BKV-positive patients.

Discussion: The results obtained here show a relatively lower prevalence of BKV and JCV in immunocompromised renal transplant receivers and healthy control than those reported from other areas in Iran. JCV genotyping was evaluated for the first time in Iran. Genotype I for JCV and genotype II for BKV were dominant genotypes in the north of Iran.

Hepatitis delta virus (HDV) is considered a satellite virus that requires hepatitis B virus surface antigen for infectivity. HDV is endemic in some Pacific Island (PI) countries, including Kiribati and Nauru, with a unique genotype 1, "Pacific clade." The aims of this study were to determine the HDV genotypes in New Zealand and investigate the link of strains to other PI countries and the rest of the world through phylogenetics. Sequencing and phylogenetic analyses were performed on 16 HDV-positive serum samples from 14 individuals collected between 2009 and 2014 at Auckland Hospital. Thirteen of 14 strains were confirmed as genotype 1 and 1 was genotype 5. Eleven of the 13 genotype 1 strains clustered with the Pacific clade. These were isolated from subjects born in Samoa, Kiribati, Tuvalu, and Niue. Another genotype 1 strain isolated from a Maori health-care worker clustered most closely with a European strain. There was an African genotype 1 and genotype 5 from African-born subjects with HIV coinfection. This study supports the probable transmission of HDV Pacific clade around the PI from Micronesia to Polynesia. The data also confirm the need to screen hepatitis B surface antigen-positive individuals for HDV.

Introduction: Herpes simplex viruses (HSVs) are widely distributed in the human population. HSV type 1 (HSV-1) is responsible for a spectrum of diseases, ranging from gingivostomatitis to keratoconjunctivitis, and encephalitis. The HSVs establish latent infections in nerve cells, and recurrences are common. Their frequent reactivation in elderly and immunosuppressed patients causes serious health complications.

Objectives: Due to the growing resistance to its main drug, acyclovir, alternative treatments with different mechanisms of action are required. MicroRNAs regulate host and viral gene expression posttranscriptionally. Previous studies reported that mir-101-2 expression has widely participated in the regulation of HSV-1 replication. In this study, we investigate the effect of hsa-miR-101-1 in the replication of HSV-1.

Methods: We found that transfection of miR-101-1 into HeLa cells could reduce effectively HSV-1 replication using plaque assay and real-time PCR methods.

Results: We showed that overexpression of miR-10-1 produced less viral progeny and manifested a weaker cytopathic effect, without affecting cell viability.

Discussion/conclusion: This result can give us new insights into the control of HSV-1 infections.