Detection of human papillomavirus in oropharyngeal squamous cell carcinoma

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.

Simple and rapid detection of Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans by loop-mediated isothermal amplification assay

Background: Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans are two main causative agents associated with periodontitis, an inflammatory reaction of tissues around the teeth. The aim of this study was to develop and evaluate the loop-mediated isothermal amplification (LAMP) assay for simple and rapid detection of P. gingivalis and A. actinomycetemcomitans.Methods: A total of ten subgingival plaque and saliva samples were evaluated to detect the presence of both bacteria by LAMP and PCR assays. Two sets of six primers each were designed to amplify pepO and dam gene. The LAMP assay was carried out using a Loopamp DNA amplification kit in 25 μl volumes. The reaction mixture was incubated at 65oC for 60 minutes and terminated at 80oC for 5 minutes in heating block. The amplification reactions were visualized using naked eye detection and by agarose gel electrophoresis. The sensitivity of the LAMP assay was investigated ranging from 10 μg to 100fg of P. gingivalis(ATCC 33327) and A. actinomycetemcomitans (ATCC 33384).Results: The lowest detection limit of both LAMP and PCR methods were 1 ng and 10 ng of DNA, respectively. When crude template of subgingival plaques were used, P. gingivalisand A. actinomycetemcomitans were tested80% (8/10) and 60% (6/10) positive respectively through LAMP detection. Whereas by PCR, P. gingivaliswas tested 40% (4/10) positive and no significant detection rate for A. actinomycetemcomitans. When a crude template of saliva was used, P. gingivalisand A. actinomycetemcomitans were tested 70% (7/10) and 30% (3/10) positive respectively through LAMP detection. Whereas, when using PCR, there was no significant detection rate for P. gingivalisand A. actinomycetemcomitans.Conclusion: The LAMP assay using a crude template offers greater advantage as it is simple, rapid and cost-effective to detect periodontal pathogens.Bangladesh Journal of Medical Science Vol.17(3) 2018 p.402-410

Detection of blaIMP4 and blaNDM1 harboring Klebsiella pneumoniae isolates in a university hospital in Malaysia

Background

Antibiotic resistance among Enterobacteriaceae posts a great challenge to the health care service. The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) is attracting significant attention due to its rapid and global dissemination. The infection is associated with significant morbidity and mortality, thus creating challenges for infection control and managing teams to curb the infection. In Southeast Asia, there have been limited reports and subsequent research regarding CRKP infections. Thus, the study was conducted to characterize CRKP that has been isolated in our setting.

Methods

A total of 321 K. pneumoniae were included in the study. Each isolate went through an identification process using an automated identification system. Phenotypic characterization was determined using disk diffusion, modified Hodge test, Epsilometer test, and inhibitor combined disk test. Further detection of carbapenemase genes was carried out using polymerase chain reaction and confirmed by gene sequence analysis.

Results

All together, 13 isolates (4.05%) were CRKP and the majority of them were resistant to tested antibiotics except colistin and tigercycline. Among seven different carbapenemase genes studied (bla_KPC, bla_IMP, bla_SME, bla_NDM, bla_IMI, bla_VIM, and bla_OXA), only two, bla_IMP4 (1.87%) and bla_NDM1 (2.18%), were detected in our setting.

Conclusion

Evidence suggests that the prevalence of CRKP in our setting is low, and knowledge of Carbapenem-resistant Enterobacteriaceae and CRKP has improved and become available among clinicians.