BACKGROUND AND OBJECTIVE

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as the causative agent of COVID-19 has significantly challenged the public health landscape in late 2019. After almost 3 years of the first ever SARS-CoV-2 case, the World Health Organization (WHO) declared the end of this global health emergency in May 2023. Although, despite the subsequent drop of COVID-19 cases, the SARS-CoV-2 infection still exhibited multiple waves of infection, primarily attributed to the appearance of new variants. Five of these variants have been classified as Variants of Concern (VOC): Alpha, Beta, Gamma, Delta, and the most recent, Omicron. Therefore, the development of methods for the timely and accurate detection of viral variants remains fundamental, ensuring an ongoing and effective response to the disease. This study aims to evaluate the feasibility of the application of an in-house approach in genomic surveillance for the detection of SARS-CoV-2 variants using in silico designed primers.

The primers used for the study were particularly designed based on conserved regions of certain genes in the virus, targeting distinct mutations found in known variants of SARS-CoV-2. Viral RNA extracts from nasopharyngeal samples (n=14) were subjected to quantitative and qualitative tests (Nanodrop and AGE). Selected samples were then analyzed by RT-PCR and amplicons were submitted for sequencing. Sequence alignment analysis was carried out to identify the prevailing COVID-19 variant present in the sample population.

The study findings demonstrated that the in-house method was able to successfully amplify conserved sequences (spike, envelope, membrane, ORF1ab) and enabled identification of the circulating SARS-CoV-2 variant among the samples. Majority of the samples were identified as Omicron variant. Three out of four designed primers effectively bound into the conserved sequence of target genes present in the sample, revealing the specific SARSCoV-2 variant. The detected mutations characterized for Omicron found in the identified lineages included K417N, S477N, and P681H which were also identified as mutations of interest. Furthermore, identification of the B.1.448 lineage which was not classified in any known variant also provided the potential of the developed in-house method in detecting unknown variants of COVID-19.

Among the five VOCs, Omicron is the most prevalent and dominant variant. The in-house direct PCR product sequencing surveillance (DPPSS) method provided an alternative platform for SAR-CoV-2 variant analysis which is accessible and affordable than the conventional diagnostic surveillance methods and the whole genome sequencing. Further evaluation and improvements on the oligonucleotide primers may offer significant contribution to the development of a specific and direct PCRbased detection of new emerging COVID-19 variants.

BACKGROUND AND OBJECTIVE

Nontuberculous mycobacteria (NTM) lung disease appears like tuberculosis infection but is resistant to primary anti-tuberculosis drugs. Hence, patients whose sputum sample tests positive for acid-fast bacilli (AFB) and bacterial culture for several times should be assessed for colonization or infection with NTM in a damaged lung secondary to TB. In such cases, though drug-resistant TB may be adequately treated, treatment may need to be directed towards the NTM as well. In NTM therapy, the duration and choice of treatment agent is based upon the specific organism and disease extent. This study used one-step multiplex PCR (mPCR) assay for rapid differentiation of solid cultures in Ogawa medium as Mycobacterium tuberculosis (MTB) and/or NTM.

A total of 80 stocked isolates obtained from the Lung Center of the Philippines from January to December 2018 were screened for NTM in terms of growth in Ogawa medium, acid fastness, and MPT64 TB antigen test result. These were from sputum specimens of multidrug-resistant tuberculosis (MDR-TB) patients. DNA was extracted from cultures (n=55) grown in Ogawa medium and one-step mPCR was performed to identify NTM to the species level.

Out of 80 samples screened, a total of 55 isolates were identified as NTM. One-step mPCR identified 12.73% (7/55) as M. abscessus, 34.55% (19/55) as M. massiliense, 1.82% (1/55) as M. kansasii, and 50.91% (28/55) were identified only up to genus Mycobacteria spp. Neither M. avium complex nor M. intracellulare was identified among the samples tested.

One-step mPCR was able to identify isolates as MTB or NTM coinciding with the initial screening using MPT64 TB antigen test. Multiplex PCR has given a more specific identificati on to the species level. The use of mPCR in identifying MTB and clinically significant NTM’s is suitable for the adequate treatment of mycobacterial infection.

Human ; Bacteria ; Antimicrobial Stewardship ; Insemination, Artificial, Heterologous ; Multiplex Polymerase Chain Reaction ; Polymerase Chain Reaction

OBJECTIVES

To validate a method in detecting SARS-CoV-2 via RT-qPCR in pregnant and non-pregnant samples other than nasopharyngeal swabs and/or oropharyngeal swabs such as cervical, rectal, amniotic fluid, placental, umbilical cord blood, and breastmilk.

We performed a validation experiment using MGI easy extraction kits and BGI PCR kits on non-conventional specimens, including cervical, rectal, amniotic fluid, placental, umbilical cord blood, and breastmilk to detect and confirm the presence of SARS-CoV-2. In addition, we tested the validated method on 572 purposively sampled field-collected non-conventional specimens from a cohort of 109 unvaccinated pregnant and 47 unvaccinated non-pregnant women to assess which candidate non-conventional maternal- and fetal-associated specimens may contribute to maternal-fetal viral vertical transmission.

Positive detection of SARS-CoV-2 viral RNA in non-conventional specimens was demonstrated and verified. Of the 572 non-conventional samples tested, 1.8% (10/572) were positively validated by RT-qPCR for SARS-CoV-2 in the maternal-associated specimens particularly the rectal (5), placental (1), and cervical (4) swabs among six pregnant and four non-pregnant individuals. In contrast, no SARS-CoV-2 viral RNA was detected in fetal-associated specimens.

The results of the validation study may serve as an additional diagnostic screening layer to support maternal-child care. Furthermore, viral detection in these non-conventional maternal specimens may also be utilized to provide guidance in the clinical management of neonates, and pregnant women during delivery.

BACKGROUND

Broad  Panel Respiratory Multiplex PCR (Pneumonia Panel) tests a panel of bacteria and viruses associated with community acquired pneumonia (CAP) which help streamline antimicrobial therapy. Recently, pneumonia panel aids clinicians in early streamlining of antimicrobials as opposed to waiting for bacterial culture results [2].

To determine whether the use of pneumonia panel improves the overall survival rate, length of hospital stay, and number of antibiotic free days among hospitalized CAP patients.

In this RCT, adult patients admitted for CAP were randomized to perform pneumonia panel and sputum culture (pneumonia panel group) versus sputum culture only (control group). The results were relayed to the medical team and were incorporated into the medical records. Length of hospital stay, antibiotic free days in day 28, and mortality rates were the primary outcomes measured.

Eighty participants completed the study. There was no significant difference in the length of hospital stay (p-value 0.073, 95% C.I.), duration of antibiotic therapy (p-value 0.332, 95% C.I.), and mortality rates (p-value 0.570, 95% C.I.) between the 2 groups.

Routine use of pneumonia panel does not significantly reduce length of hospital stay, duration of antibiotic therapy, and mortality rates among admitted patients with moderate to severe CAP. The benefit of pneumonia panel was seen on early detection of drug resistant pathogen resulting in early antibiotic escalation and shorter duration of antibiotic therapy. Further studies are necessary to show its benefit in the high risk population.

Clostridioides difficile/genetics* ; Clostridioides ; Real-Time Polymerase Chain Reaction ; Feces ; Bacterial Proteins/genetics*

OBJECTIVE: To develop a polymerase chain reaction-sequence specific primer (PCR-SSP) method for simultaneous amplification and identification of the KIR genes among Chinese population. METHODS: Peripheral blood samples from 132 healthy donors who had given blood at Shenzhen Blood Center from January 2015 to November 2015 were selected as the study subjects. Based on the polymorphism and single nucleotide polymorphism (SNP) information of high-resolution KIR alleles in the Chinese population and the IPD-KIR database, specific primers were designed to amplify all the 16 KIR genes and the 2DS4-Normal and 2DS4-Deleted subtypes. The specificity of each pair of PCR primers was verified by using samples with known KIR genotypes. During PCR amplification of the KIR gene, co-amplification the fragment of human growth hormone (HGH) gene by multiplex PCR was used as the internal control to prevent false negative results. A total of 132 samples with known KIR genotypes were randomly selected for blind inspection to verify the reliability of the developed method. RESULTS: The designed primers can specifically amplify the corresponding KIR genes, with clear and bright bands for the internal control and KIR genes. The results of detection are fully consistent with the known results. CONCLUSION The KIR PCR-SSP method established in this study can yield accurate results for the identification of the presence of KIR genes.
Humans ; Receptors, KIR/genetics* ; Reproducibility of Results ; Polymorphism, Genetic ; Genotype ; Multiplex Polymerase Chain Reaction

OBJECTIVES: To study the association of ventricular septal defect (VSD) with rare variations in the promoter region of HAND2 gene, as well as related molecular mechanisms. METHODS: Blood samples were collected from 349 children with VSD and 345 healthy controls. The target fragments were amplified by polymerase chain reaction and sequenced to identify the rare variation sites in the promoter region of the HAND2 gene. Dual-luciferase reporter assay was used to perform a functional analysis of the variation sites. Electrophoretic mobility shift assay (EMSA) was used to investigate related molecular mechanisms. TRANSFAC and JASPAR databases were used to predict transcription factors. RESULTS: Sequencing revealed that three variation sites (g.173530852A>G, g.173531173A>G, and g.173531213C>G) were only observed in the promoter region of the HAND2 gene in 10 children with VSD, among whom 4 children had only one variation site. The dual-luciferase reporter assay revealed that g.173531213C>G reduced the transcriptional activity of the HAND2 gene promoter. EMSA and transcription factor prediction revealed that g.173531213C>G created a binding site for transcription factor. CONCLUSIONS The rare variation, g.173531213C>G, in the promoter region of the HAND2 gene participates in the development and progression of VSD possibly by affecting the binding of transcription factors.
Child ; Humans ; Base Sequence ; Heart Septal Defects, Ventricular/genetics* ; Polymerase Chain Reaction ; Promoter Regions, Genetic ; Transcription Factors/genetics*

OBJECTIVES: To compare the effects of cell lysis method and magnetic beads method in forensic DNA identification and to explore these two methods in forensic DNA identification. METHODS: The genome DNA of THP-1 cells in different quantities was extracted by the cell lysis method and magnetic beads method, and the DNA content was quantified by real-time quantitative PCR. The cell lysis method and magnetic beads method were used to type the STR of human blood with different dilution ratios. RESULTS: When the numbers of THP-1 cell were 100, 400 and 800, the DNA content extracted by cell lysis method were (1.219±0.334), (5.081±0.335), (9.332±0.318) ng, respectively; and the DNA content extracted by magnetic beads method were (1.020±0.281), (3.634±0.482), (7.896±0.759) ng, respectively. When the numbers of THP-1 cells were 400 and 800, the DNA content extracted by the cell lysis method was higher than that by the magnetic beads method. The sensitivity of cell lysis method and magnetic beads method was similar in STR typing of human blood at different dilution ratios. Complete STR typing could be obtained at 100, 300 and 500-fold dilutions of blood samples, but could not be detected at 700-fold dilution. STR typing of undiluted human blood could not be detected by cell lysis method. CONCLUSIONS The cell lysis method is easy to operate and can retain template DNA to the maximum extend. It is expected to be suitable for trace blood evidence tests.
Humans ; Forensic Medicine ; DNA/genetics* ; Real-Time Polymerase Chain Reaction ; Magnetic Phenomena ; DNA Fingerprinting/methods* ; Microsatellite Repeats

Humans ; SARS-CoV-2 ; COVID-19 ; Reverse Transcriptase Polymerase Chain Reaction ; Immunosuppression Therapy ; COVID-19 Testing