Throat Wash Specimens Research Articles

Direct comparison of Altona-SARS-CoV-2 dual target RT-qPCR Assay with commercial LAMP Assay using throat washes in health care staff testing

BackgroundRapid molecular diagnostics by PCR has a crucial role in handling the global SARS-CoV-2 pandemic. As diagnoses are time-sensitive and global supply chains are susceptible to various factors alternative detection methods would be an important backup. ObjectivesDuring the study the performance of a commercially available isothermal LAMP method for SARS-CoV-2 detection was compared to a IVD RT-PCR Assays using throat wash specimens that were routinely taken in our hospital setting. Study designThroat wash specimens of hospital staff (n = 174) previously tested positive for SARS-CoV-2 by the Altona Diagnostics RealStar SARS-CoV-2 RT-PCR (Altona Diagnostics, Hamburg, Germany) was tested for SARS-CoV-2 also by the SARS-CoV-2 Rapid Colorimetric LAMP Assay (NEB Germany GmbH, Frankfurt a.M., Germany). ResultsThe sensitivity of the colorimetric LAMP Assay compared to RT-qPCR was 78.74%, and the specificity was determined to 88.24% with a positive predictive value of 0.986 and a negative predicitve value of 0.882. The positive and negative likelihood ratio for LAMP was 6.693 and 0.241, respectively, while the diagnostic odds ratio was 27.77. ConclusionsIn times of limited PCR test ressources and in settings with limited PCR capacities, the colorimetric LAMP Assay could serve as an alternative, if a calculable loss of sensitivity is acceptable from the Public Health perspective in certain settings.

Nasopharyngeal carcinoma risk prediction via salivary detection of host and Epstein-Barr virus genetic variants.

Genetic susceptibility and Epstein-Barr virus (EBV) infection are important etiological factors in nasopharyngeal carcinoma (NPC). In this study, in southern China, where NPC is endemic, a single nucleotide polymorphism (SNP) in the EBV-encoded RPMS1 gene (locus 155391: G > A [G155391A]) and seven host SNPs (rs1412829, rs28421666, rs2860580, rs2894207, rs31489, rs6774494, and rs9510787) were confirmed to be significantly associated with NPC risk in 50 NPC cases versus 54 hospital-based controls with throat washing specimens and 1925 NPC cases versus 1947 hospital-based controls with buffy coat samples, respectively. We established a strategy to detect the NPC-associated EBV and host SNPs using saliva samples in a single test that is convenient, noninvasive, and cost-effective and displays good compliance. The potential utility of this strategy was tested by applying a risk prediction model integrating these EBV and host genetic variants to a population-based case-control study comprising 1026 incident NPC cases and 1148 controls. Receiver operating characteristic (ROC) curve analysis revealed an area under the curve of the NPC risk prediction model of 0.74 (95% CI: 0.71−0.76). Net reclassification improvement (NRI) analysis showed that inclusion of the EBV SNP significantly improved the discrimination ability of the model (NRI = 0.30, P < 0.001), suggesting the promising value of EBV characteristics for identifying high-risk NPC individuals in endemic areas. Taken together, we developed a promising NPC risk prediction model via noninvasive saliva sampling. This approach might serve as a convenient and effective method for screening the population with high-risk of NPC.

Meningococcal carriage rates in healthy individuals in Japan determined using Loop-Mediated Isothermal Amplification and oral throat wash specimens.

The detailed epidemiology of meningococcal diseases in Japan has yet to be determined and, moreover, the healthy carriage rate is also unknown. In this study, to obtain insight into the carriage rate of Neisseria meningitidis in healthy individuals in Japan, we developed a new method to detect the N.meningitidis-specific ctrB gene, one of the genes encoding enzymes for capsule synthesis, by Loop-Mediated Isothermal Amplification (LAMP) and examined the meningococcal carriage rate by using self-collected oral throat wash specimens from 836 students at a university. Examination by LAMP showed that 7 out of 836 samples were positive for N.meningitidis DNA, and the results were also verified by the nested PCR method for the meningococcus specific ggt gene. The N.meningitidis carriage rate in healthy individuals was estimated to be 0.84%. Moreover, we further confirmed by the nested-PCR-based serogroup typing method that 5 of the positive samples belonged to serogroup Y, 1 belonged to group B and 1 was unidentifiable. Considering the epidemiology for meningococcal diseases in Japan, the carriage rate and the serogroup profile seem to be consistent with low incidence of meningococcal diseases and serogroup distribution of clinical meningococcal isolates in Japan, respectively.

Molecular Detection of 16SrRNA of Chlamydia pneumoinae and specific IgE in Asthmatic Patients

Background: Chlamydia pneumoniae is an obligate intracellular organism and it is one of the common causes of upper respiratory tract infection. Microbes were blamed to trigger asthma in different mechanisms, one of these microbes is Chlamydia pneumoniae. Aims of the study: This study was done to show the rate of Chlamydia pneumoniae infection in asthmatic patients through detection of 16SrRNA of Chlamydia pneumoniae in blood and throat wash of patients using PCR test. Methods: One hundred (120) asthmatic patients from both sexes and different age groups (2-84 years) were included in this study. These patients were attending the Clinic of Allergy and Asthma in Ramadi General Teaching Hospital, during the period extended from January to March 2011. Thirty (30) healthy individuals from both sexes were selected randomly to be considered as negative control group. Blood specimens (5ml) and throat wash were taken from each patient, were employed for the detection of 16SrRNA of Chlamydia pneumoniae using PCR test. Pooled sera from 70 patients were employed for detection of IgE specific for Chlamydia pneumoniae using ELIZA test. Results: PCR test results of Blood specimens: Among of 70 tested sera from asthmatic patients from both attack and remittance, thirty five (35), (50%) of the tested specimens were showing positive PCR test. Among patients, adult females were showing more positive PCR results for 16s r RNA of Chlamydia pneumoinae in their blood specimens 22 females (10, at attack and 12 at remittance), while all tested specimens from control group individuals were showing negative PCR results. Out of (50) tested throat wash specimens, five (5), (10%) of them were showing positive PCR for 16s r RNA of Chlamydia pneumoinae. Four (4) (8o%) of them were from adult patients at attack status and all control group individuals were showing negative PCR results IgE Specific for Chlamydia pneumoinae antigen, out of (54) tested sera from asthmatic patients, 37 of them were showing positive ELISA test for IgE specific for Chlamydia pneumoniae antigen, Adult females (24, (64. 8) were showing higher IgE positive results than males (P < o.o5). All tested sera (15) from control group individuals were showing negative IgE Chlamydia pneumoniae antigen. Positive correlation was found between the results of IgE specific for Chlamydia pneumoniae and PCR results for blood and throat wash specimens in both attack and remittance. Conclusion: We can conclude from this study that Chlamydia pneumoinae is involved with asthma post infection to the lower respiratory tract and induction of allergy mediators like IgE in both sexes.

P3-S1.19 Evaluation of the cobas® 4800 CT/NG test using clinician and self-collected vaginal swabs, cervical specimens in PreservCyt solution, and pharyngeal throat wash specimens

ObjectiveTo evaluate the limit of detection (LOD), inclusivity, exclusivity, and interfering substances of the cobas® 4800 CT/NG Test using vaginal, PreservCyt, and pharyngeal specimens.MethodsChlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG)...

Pharyngeal Neisseria gonorrhoeae detection in oral-throat wash specimens of male patients with urethritis

Detection of Neisseria gonorrhoeae and Chlamydia trachomatis in the pharynx has been highlighted in the prevention of the unexpected spread of sexually transmitted diseases. We tried to clarify the detection rate of Neisseria gonorrhoeae in the pharynx and the clinical relevance of oral-throat wash specimens to detect the organism in heterosexual men with gonococcal and nongonococcal urethritis. In our cohort of 79 male patients with urethritis, oral throat wash specimens were collected after they had gargled with normal saline for approximately 30 to 60 s. Positive pharyngeal N. gonorrhoeae was defined as a positive result on the strand displacement amplification test for the specimen from the oral-throat wash. N. gonorrhoeae was detected in the oral-throat wash specimens of 13 (31.7%) of the 41 male patients with gonococcal urethritis. Oral-throat wash with a nucleic acid amplification test can detect pharyngeal N. gonorrhoeae easily and efficiently.

Multiplex RT-PCR for the rapid detection of influenza virus types and subtypes

To establish a sensitive and specific multiplex RT-PCR(MRT-PCR) for the simultaneous detection of influenza virus types and subtypes. Primers were designed from highly conserved region of the hemagglutinin(HA) gene of influenza H1N1H3N2 and B virus and MRT-PCR was performed. Additional two pairs of primers were designed to determine the N1 and N2 subtypes of neuramidinase NA of influenza H1N1 and H3N2 virus. The fragments of HA gene of all types of influenza virus were amplified and there was no cross reaction. The sensitivity of detection of influenza H1N1 and H3N2 virus was 0.10 TCID50/50 microliter by the second PCR and that was 0.01 TCID50/50 microliter for influenza B virus. The NA gene of influenza H1N1 and H3N2 virus was also amplified by this method. The sensitivity of detection of influenza virus from clinical patients' throat washing specimens by MRT-PCR was higher than that by MDCK cell culture or egg embryo isolation. This method was highly sensitive and timely for detection of influenza virus types and subtypes.

Identification of Epstein-Barr virus strain variants in hairy leukoplakia and peripheral blood by use of a heteroduplex tracking assay.

Epstein-Barr virus (EBV) strains can be distinguished by specific sequence variations in the LMP1 gene. In this study, a heteroduplex tracking assay (HTA) specific for LMP1 was developed to precisely identify the prototypic undeleted strain B958, other undeleted strains (Ch2, AL, NC, and Med-), and strains with the 30-bp deletion (Med+ and Ch1). This technique also provides an estimate of the relative abundance of strains in patient samples. In this study, EBV strains were identified in 25 hairy leukoplakia (HLP) biopsies and six matched peripheral blood samples and throat washes with the LMP1-HTA. To investigate the relationship of the virus found in the peripheral blood to that in the HLP lesion, the strain variants in the peripheral blood B lymphocytes and those present within the epithelial cells in the HLP lesion and in throat washes were identified. In many of the subjects, compartmental differences in the EBV strain profiles in the oral cavity and peripheral blood were readily apparent. The throat wash specimens usually had a strain profile similar to that within the corresponding HLP sample, which was distinct from the strain profile detected in the peripheral blood. These analyses reveal that the nature of EBV infection can be very dynamic, with changes in relative strain abundance over time as well as the appearance of new strains. The patterns of abundance in the blood and oral cavity provide evidence for compartmentalization and for the transmission of strains between the blood and oropharynx.

Enhanced shedding of cytomegalovirus in semen of human immunodeficiency virus-seropositive homosexual men.

Site-specific shedding of cytomegalovirus (CMV) was assessed in a longitudinal study of homosexual and bisexual men. At initial testing, CMV was cultured from the semen of 33% (19 of 58) of asymptomatic and mildly symptomatic men who were seropositive for human immunodeficiency virus (HIV) at the time of entry into the study, whereas it was cultured from the semen of 17% (10 of 58) of the men who were HIV seronegative. CMV was isolated much more frequently from semen than from urine or throat washing specimens, and it was rarely recovered from stool or blood, regardless of the subject's HIV serostatus. CMV was cultured from the semen of 31% (16 of 52) of the men relatively early after seroconversion to HIV (mean, 12.8 months). CMV was persistently isolated from the semen of a greater proportion of the HIV-seropositive men than from the semen of the HIV-seronegative men during a 4.5-year follow-up period (52 of 110 - [47%] and 15 of 58 [26%] men, respectively). There was an increased relative risk for shedding of CMV in semen in association with decreased CD4+ cell numbers and increased levels of serum immunoglobulin A. However, there was no association of CMV shedding with an increased risk for the development of AIDS.

Agglutination of human O erythrocytes by influenza A(H1N1) viruses freshly isolated from patients

The hemagglutinin titers of 10 influenza A(H1N1) viruses were examined using the erythrocytes of several species. Human O erythrocytes showed the highest agglutination titer to the viruses, whereas chicken erythrocytes showed a low titer. These findings were noted for at least 10 passages by serial dilutions of the viruses in Madin-Darby canine kidney (MDCK) cells. All influenza A(H1N1) viruses, plaque-cloned directly from throat-washing specimens of patients, also agglutinated human O but not chicken erythrocytes.The results of a hemadsorption test indicated that chicken erythrocytes possess less affinity to MDCK cells infected with the A/Osaka City/2/88(HlNl) strain than to those infected with the A/Yamagata/120/86(H1N1) strain which is used as an inactivated influenza vaccine in Japan. However, there were no significant differences between the A/Osaka City/2/88 and the A/Yamagata/120/86 strains in the hemagglutination inhibition test.Since human O erythrocytes have high agglutination activity to influenza A(H1N1) and also to A(H3N2) and B viruses in MDCK cells, these erythrocytes may be useful for the serological diagnosis of influenza.