In Vitro Antimicrobial Activity and Aggregation Abilities of Probiotic Lactobacillus casei and Lactobacillus salivarius Against Oral Pathogens

ABSTRACT@#The antagonistic effect of probiotics against oral pathogens merits exploration because these bacteria are beneficial to the host’s health. The antimicrobial activity of two probiotic strains, Lactobacillus casei and Lactobacillus salivarius, as well as L. casei and L. salivarius combination (1:1), was investigated against Streptococcus mutans, Streptococcus sobrinus, Candida albicans, Candida glabrata and Candida tropicalis using agar-well diffusion, auto-aggregation and coaggregation assays. L. salivarius cell-free supernatant (CFS) alone exhibited greater inhibitory effect against Streptococci spp. compared to L. casei CFS alone and the combination. However, no inhibition was observed for Candida spp. L. salivarius alone exhibited significantly stronger auto-aggregation than L. casei alone (p ≤ 0.05) and L. casei and L. salivarius combination. L. salivarius exhibited strong coaggregation ability with Candida spp., followed by Streptococci spp. while L. casei exhibited coaggregation only with Streptococci spp. However, L. casei and L. salivarius combination did not display any coaggregation with all strains. L. salivarius alone exhibited a stronger antagonistic effect on the tested organisms than L. casei alone or in combination. Based on the results, both probiotic strains showed good antimicrobial activities against oral pathogens and should be further studied for their human health benefits.

Detection of human papillomavirus in oropharyngeal squamous cell carcinoma / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Worldwide there has been a significant increase in the incidence of oropharyngeal squamous cell carcinoma (OPSCC) etiologically attributed to oncogenic human papillomavirus (HPV). Reliable and accurate identification and detection tools are important as the incidence of HPV-related cancer is on the rise. Several HPV detection methods for OPSCC have been developed and each has its own advantages and disadvantages in regard to sensitivity, specificity, and technical difficulty. This review summarizes our current knowledge of molecular methods for detecting HPV in OPSCC, including HPV DNA/RNA polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), p16 immunohistochemistry (IHC), and DNA/RNA in situ hybridization (ISH) assays. This summary may facilitate the selection of a suitable method for detecting HPV infection, and therefore may help in the early diagnosis of HPV-related carcinoma to reduce its mortality, incidence, and morbidity.

Sensitivity Evaluation of SYBR Green I, SYBR Safe and Calcein Dyes for Detection of Human Papillomavirus 16 by Loop-Mediated Isothermal Amplification

Loop-mediated isothermal amplification (LAMP) is a gene amplification technique whereby the amplification products are commonly visualized as turbidity by naked eye in the presence of magnesium pyrophosphate precipitation. An appropriate intercalating dye is important as it could increase the sensitivity and reduce the false positive and false negative results for the detection. The study aimed to compare the performance of three different intercalating dyes; SYBR Green I, SYBR Safe and calcein-based dyes in HPV-16 LAMP assay by naked-eye visualization, gel electrophoresis and real-time monitoring. The LAMP assay was carried out using a Loopamp DNA amplification kit in 25 μl volumes. The reaction mixture was incubated at 60�C for 60 mins and terminated at 80�C for 5 mins in a real-time turbidimeter. For naked eye detection, SYBR Green I and SYBR Safe were diluted at 1:10 of DMSO and was added to the solution after the reaction was completed while calcein was added before the amplification process. The sensitivity of the LAMP assay was investigated ranging from 101 copies/μl to 108 copies/μl of the HPV 16 DNA template. All three dyes exhibited similar results in term of sensitivity with the detection limit of 103 copies/μl. Addition of calcein dye showed decrease in detection time by 10 mins by real-time turbidimeter. The performance all three dyes for naked-eye detection are comparable and can be used for endpoint screening applications in HPV 16 assay, whereas in real-time evaluation, addition of calcein delay the detection time by 10 mins.

Updates on Knowledge, Attitude and Preventive Practices on Tuberculosis among Healthcare Workers

Ranking as the most communicable disease killer worldwide, tuberculosis, has accounted with a total of 9.6 million new tuberculosis cases with 1.5 million tuberculosis-related deaths reported globally in 2014. Tuberculosis has remain as an occupational hazard for healthcare workers since 1920s and due to several tuberculosis outbreaks in healthcare settings in the early 1990s, the concern about the transmission to both patients and healthcare workers has been raised. Healthcare workers have two to three folds greater the risk of active tuberculosis than the general population. Several studies on knowledge, attitude and practices on tuberculosis among healthcare workers worldwide have revealed that majority of the participated healthcare workers had good knowledge on tuberculosis. Most of the healthcare workers from South India and South Africa also reported to have positive attitude whereas a study in Thailand reported that most of the healthcare providers have negative attitude towards tuberculosis patients. Nevertheless, majority of the healthcare workers have low level of practice on tuberculosis prevention. An improved communication between healthcare workers and the patients as well as their families is the key to better therapeutic outcomes with good knowledge, attitude and preventive practice towards tuberculosis.

Genotypic Detection of rpoB and katG Gene Mutations Associated with Rifampicin and Isoniazid Resistance in Mycobacterium Tuberculosis Isolates: A Local Scenario (Kelantan)

Background: Drug resistant tuberculosis (DR-TB) remains a public health issue that is of major concern on a global scale. The characterisation of clinical isolates may provide key information regarding the underlying mechanisms of drug resistance, and helps to augment therapeutic options. This study aims to evaluate the frequency of gene mutations associated with Rifampicin (RIF) and Isoniazid (INH) resistance among nine clinical isolates. Methods: A total of nine drug resistant Mycobacterium tuberculosis clinical isolates were screened for genetic mutations in rpoB and katG using polymerase chain reaction (PCR) amplification and DNA sequencing. Genotypic analysis was performed to detect the mutations in the sequence of the target genes. Results: Our findings reveal that 80% of the isolates possess mutations at codon 119 (His119Tyr) and 135 (Arg135Trp and Ser135Leu) within the rpoB gene; and 70% possess mutations in the katG gene at codon 238 with amino acid change (Leu238Arg). Conclusion: Findings from this study provide an overview of the current situation of RIF and INH resistance in a hospital Universiti Sains Malaysia (HUSM) located in Kelantan, Malaysia, which could facilitate molecular-based detection methods of drug-resistant strains. Further information regarding the molecular mechanisms involved in resistance in RR-/MDR-TB should be addressed in the near future.

Sequence comparison of six human microRNAs genes between tuberculosis patients and healthy individuals

Objective/Background: MicroRNAs [miRNAs] play an important role in diseases development. Therefore, human miRNAs may be able to inhibit the survival of Mycobacterium tuberculosis [Mtb] in the human host by targeting critical genes of the pathogen. Mutations within miRNAs can alter their target selection, thereby preventing them from inhibiting Mtb genes, thus increasing host susceptibility to the disease

Methods: This study was undertaken to investigate the genetic association of pulmonary tuberculosis [TB] with six human miRNAs genes, namely, hsa-miR-370, hsa-miR-520d, hsamiR- 154, hsa-miR-497, hsa-miR-758, and hsa-miR-593, which have been predicted to interact with Mtb genes. The objective of the study was to determine the possible sequence variation of selected miRNA genes that are potentially associated with the inhibition of critical Mtb genes in TB patients

Results: The study did not show differences in the sequences compared with healthy individuals without antecedents of TB

Conclusion: This result could have been influenced by the sample size and the selection of miRNA genes, which need to be addressed in future studies

In-vitro antimicrobial effectiveness of herbal-based mouthrinses against oral microorganisms

OBJECTIVE: To evaluate the in vitro antimicrobial effectiveness of commercial herbal-based mouthrinses against oral microorganisms. METHODS: A total of three mouthrinses (OX, Pesona and Watsons) were tested for their antimicrobial activity against six oral organisms, Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Lactobacillus salivarius (L. salivarius), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Candida albicans (C. albicans) by standard agar-disk diffusion assay. Oradex mouthrinse containing 0.12% chlorhexidine gluconate and sterile distilled water was served as positive and negative controls, respectively. RESULTS: All mouthrinse formulations were effective in inhibiting the growth of S. mutans, S. sobrinus, L. salivarius and C. albicans. Among the tested mouthrinses, Pesona was the only effective mouthrinse against S. aureus and P. aeruginosa, similar to Oradex mouthrinse. Pesona mouthrinse formulation appears to be as effective as Oradex mouthrinse formulation to kill S. aureus and P. aeruginosa. Statistical analysis showed no significant difference among the tested formulations regarding their antimicrobial activities (P > 0.05). CONCLUSIONS: Pesona was not the only herbal mouthrinse effective in inhibiting the growth of S. mutans, S. sobrinus, L. salivarius and C. albicans in vitro. All tested formulations were effective against those strains. Our findings may serve as a guide for selecting a kind of herbal mouthrinses as well as providing information to the dental professionals about the efficacy of these products.

The Deadly Ebola Threat in the Midst of an Overwhelming Dengue Epidemic

The recent death tolls and morbidities associated with two deadly viral haemorrhagic fevers (VHFs), i.e., Ebola and dengue, are simply shocking. By the end of August 2014, 65 672 people were afflicted with dengue fever (DF) in Malaysia, with 9505 from Kelantan, and there were 128 reported deaths. More astounding are the death tolls associated with Ebola: 3091 deaths from 6574 reported cases so far. It is not difficult to imagine the potential disaster if Ebola spreads beyond Africa. VHFs are characterised by an acute onset of fever, vascular disruption and a rapid progression to shock and death. The revised World Health Organization (WHO) 2012 classification (dengue with and without warning signs and severe dengue) is more clinically relevant and allows more streamlined admission. With good administrative support and public health and governmental efforts, the dengue epidemic in Malaysia is now more contained. However, there should be no laxity with the imminent lethal Ebola threat. Human-to-human transmission is an important mechanism for the spread of Ebola, and this calls for strict precautions regarding contact with any suspected cases. In contrast, the control and elimination of dengue would require successful control of the vectors and their breeding sites.