Intestinal colonization against Vibrio cholerae: host and microbial resistance mechanisms.

Vibrio cholerae is a non-invasive enteric pathogen known to cause a major public health problem called cholera. The pathogen inhabits the aquatic environment while outside the human host, it is transmitted into the host easily through ingesting contaminated food and water containing the vibrios, thus causing diarrhoea and vomiting. V. cholerae must resist several layers of colonization resistance mechanisms derived from the host or the gut commensals to successfully survive, grow, and colonize the distal intestinal epithelium, thus causing an infection. The colonization resistance mechanisms derived from the host are not specific to V. cholerae but to all invading pathogens. However, some of the gut commensal-derived colonization resistance may be more specific to the pathogen, making it more challenging to overcome. Consequently, the pathogen has evolved well-coordinated mechanisms that sense and utilize the anti-colonization factors to modulate events that promote its survival and colonization in the gut. This review is aimed at discussing how V. cholerae interacts and resists both host- and microbe-specific colonization resistance mechanisms to cause infection.

Genetic Diversity among Methicillin-Resistant Staphylococcus aureus in Malaysia (2002-2020).

1. BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) is a common organism seen in both healthcare-associated and community-associated infections worldwide and in Malaysia over the past two decades. The aim of this review is to provide a firsthand documentation of all MRSA strains prevalent in the Malaysian population from 2002 to present and briefly describe the changing patterns. 2. METHODS: Electronic and manual intensive literature searches were conducted between 2002 and 2020, addressing issues directly related to patients and published in the English language were selected. 3. RESULTS: The literature search retrieved a total of 2217 articles and abstracts of 27 articles. The search yielded a total of 24 articles on genotyping of MRSA in Malaysia. The study found that MRSA strains were mostly genetically related and resulted in the predominant MRSA clones that caused active infections. Thirty-six different sequence types (ST) were recorded. The highest rates of STs detected were ST239 (52.6%), ST1 (47.4%), and ST22 (42.1%). The majority of studies showed that both SCCmec types III and IV were the most common SCCm type in Malaysia, followed by SCCmec type V (57.9%). 4. CONCLUSIONS: Both Brazilian (ST 239 IIIA) and Hungarian (ST 239-III) MRSA strains were detected in Malaysia. PFGE remains the best method for comparing MRSA strains. However, whole-genome sequencing has a promising chance to replace PFGE in the future.

Different Domains of Dengue Research in Malaysia: A Systematic Review and Meta-Analysis of Questionnaire-Based Studies.

This review provided a systematic overview of the questionnaire-related dengue studies conducted in Malaysia and evaluated their reliability and validity used in the questionnaires. An extensive literature search was conducted using various electronic databases, including PubMed, EMBASE, Medline, and ScienceDirect. Systematic reviews and meta-analysis (PRISMA) were selected as the preferred item reporting method. Out of 88 identified dengue-related, 57 published from 2000 to April 2020 met the inclusion criteria and were included. Based on the meta-analysis, a poor mean score was obtained for knowledge (49%), attitude (44%), and preventive practice (55%). The study showed that the level of knowledge on cardinal signs and modes of transmission for dengue virus were highest among health care workers, followed by students (international and local) and lastly community residents. In treatment-seeking behaviours, only half of the respondents (50.8%) would send their child to the nearest health clinics or hospitals when a child became restless or lethargic. The acceptance rate for dengue vaccine, bacteria (Wolbachia), as a vector for dengue control and self-test diagnostic kit for dengue showed considerably high (88.4%, 70%, and 44.8%, respectively). Health belief model (HBM) constructs, such as perceived barriers, perceived severity, perceived susceptibility, self-efficacy, and perceived benefit influence prevention practices. Lastly, only 23 articles (40.3%) had piloted or pretested the questionnaire before surveying, in which three reported Cronbach's alpha coefficient (0.70-0.90). A need for active participation of communities and healthcare personnel, promotion of awareness, and safe complementary medicines, as well as assessment of psychometric properties of questionnaire use in dengue surveys in Malaysia, in order for assessing dengue reliably and valid.

Immunohistochemical, histological and ultrastructural evaluation of protection provided by cholera vaccine against V. cholerae O139.

In our previous study, complete protection was observed in rabbit immunized with 1 × 1010 CFU of live attenuated VCUSM21P vaccine against challenge with 1 × 109 CFU Vibrio cholerae O139. In the present study, we investigated whether the vaccines can effectively protect immunized animals from any pathologic changes using histological, immunohistochemical and ultrastructural techniques. Severe pathology is evident in wild type injected ileum in non-immunized, showing extensive villous destruction, edema, necrosis and inflammation with infiltration of large numbers of inflammatory cells, extensive damage to the villi and microvilli with pore formation. Histology of ileum injected with wild type in immunized rabbit shows no significant pathological changes except for a few inflammatory cells in lamina propria with mild edema in mucosa and submucosa. immunohistochemical staining revealed O139 antigens of wild type are seen in the lamina propria of edematous villi, muscularis mucosa and submucosa with weak presence in the muscle coat in non-immunized rabbit after challenged with wild type in non-immunized rabbits, but in immunized rabbit localisation of the O139 LPS antigen is seen at the tips of the intact villi, within lamina propria and muscularis mucosa only. These observations suggest that the vaccine can effectively protect animals from any pathologic changes and eliminate V. cholerae O139 from the immunized animals.

Efficacy and safety of superficial chemical peeling in treatment of active acne vulgaris.

Acne vulgaris is an extremely common condition affecting the pilosebaceous unit of the skin and characterized by presence of comedones, papules, pustules, nodules, cysts, which might result in permanent scars. Acne vulgaris commonly involve adolescents and young age groups. Active acne vulgaris is usually associated with several complications like hyper or hypopigmentation, scar formation and skin disfigurement. Previous studies have targeted the efficiency and safety of local and systemic agents in the treatment of active acne vulgaris. Superficial chemical peeling is a skin-wounding procedure which might cause some potentially undesirable adverse events. This study was conducted to review the efficacy and safety of superficial chemical peeling in the treatment of active acne vulgaris. It is a structured review of an earlier seven articles meeting the inclusion and exclusion criteria. The clinical assessments were based on pretreatment and post-treatment comparisons and the role of superficial chemical peeling in reduction of papules, pustules and comedones in active acne vulgaris. This study showed that almost all patients tolerated well the chemical peeling procedures despite a mild discomfort, burning, irritation and erythema have been reported; also the incidence of major adverse events was very low and easily manageable. In conclusion, chemical peeling with glycolic acid is a well-tolerated and safe treatment modality in active acne vulgaris while salicylic acid peels is a more convenient for treatment of darker skin patients and it showed significant and earlier improvement than glycolic acid.

Efficacy and safety of superficial chemical peeling in treatment of active acne vulgaris

Abstract: Acne vulgaris is an extremely common condition affecting the pilosebaceous unit of the skin and characterized by presence of comedones, papules, pustules, nodules, cysts, which might result in permanent scars. Acne vulgaris commonly involve adolescents and young age groups. Active acne vulgaris is usually associated with several complications like hyper or hypopigmentation, scar formation and skin disfigurement. Previous studies have targeted the efficiency and safety of local and systemic agents in the treatment of active acne vulgaris. Superficial chemical peeling is a skin-wounding procedure which might cause some potentially undesirable adverse events. This study was conducted to review the efficacy and safety of superficial chemical peeling in the treatment of active acne vulgaris. It is a structured review of an earlier seven articles meeting the inclusion and exclusion criteria. The clinical assessments were based on pretreatment and post-treatment comparisons and the role of superficial chemical peeling in reduction of papules, pustules and comedones in active acne vulgaris. This study showed that almost all patients tolerated well the chemical peeling procedures despite a mild discomfort, burning, irritation and erythema have been reported; also the incidence of major adverse events was very low and easily manageable. In conclusion, chemical peeling with glycolic acid is a well-tolerated and safe treatment modality in active acne vulgaris while salicylic acid peels is a more convenient for treatment of darker skin patients and it showed significant and earlier improvement than glycolic acid

Evaluation of intestinal damage caused by V. cholerae O139, an in vivo study.

Cholera, a severe form of gastroenteritis, is one of the most widespread diseases in developing countries. The mechanism of intestinal infection caused by V. cholerae O139 remains unclear. In order to explore some morphological aspects of its infection in the intestine including Peyer's patches, we investigated the V. cholerae O139 infection at intestinal site of the rabbit gut-loop model. The electron microscopic analysis revealed denuded mucosal surface with loss of microvilli and integrity of the surface epithelium. Infection of the intestine with V. cholerae O139 induces destruction of villi, microvilli and lining epithelium with exposure of crypts of Lieberkuhn.

Construction and evaluation of V. cholerae O139 mutant, VCUSM21P, as a safe live attenuated cholera vaccine.

Cholera is a major infectious disease, affecting millions of lives annually. In endemic areas, implementation of vaccination strategy against cholera is vital. As the use of safer live vaccine that can induce protective immunity against Vibrio cholerae O139 infection is a promising approach for immunization, we have designed VCUSM21P, an oral cholera vaccine candidate, which has ctxA that encodes A subunit of ctx and mutated rtxA/C, ace and zot mutations. VCUSM21P was found not to disassemble the actin of HEp2 cells. It colonized the mice intestine approximately 1 log lower than that of the Wild Type (WT) strain obtained from Hospital Universiti Sains Malaysia. In the ileal loop assay, unlike WT challenge, 1×106 and 1×108 colony forming unit (CFU) of VCUSM21P was not reactogenic in non-immunized rabbits. Whereas, the reactogenicity caused by the WT in rabbits immunized with 1×10¹° CFU of VCUSM21P was found to be reduced as evidenced by absence of fluid in loops administered with 1×10²-1×107 CFU of WT. Oral immunization using 1×10¹° CFU of VCUSM21P induced both IgA and IgG against Cholera Toxin (CT) and O139 lipopolysaccharides (LPS). The serum vibriocidal antibody titer had a peak rise of 2560 fold on week 4. Following Removable Intestinal Tie Adult Rabbit Diarrhoea (RITARD) experiment, the non-immunized rabbits were found not to be protected against lethal challenge with 1×109 CFU WT, but 100% of immunized rabbits survived the challenge. In the past eleven years, V. cholerae O139 induced cholera has not been observed. However, attenuated VCUSM21P vaccine could be used for vaccination program against potentially fatal endemic or emerging cholera caused by V. cholerae O139.

The burden of cholera.

Cholera is an acute secretory diarrheal disease that is perceived by World Health Organization (WHO) to be a highly contagious threat. Firstly discovered by an Italian physician, Filippo Pacini, the disease gains a reputation as the most feared epidemic diarrheal disease encountered in developing countries. Despite effort taken by WHO to reduce the incidence rate, cholera-endemic prevail in certain regions. Factors that contribute to the disease transmission and ongoing spreading in cholera-prone areas remain as elusive. Should an awareness and knowledge of cholera be developed, it is the residents of developing nation that stand to benefit the most. This review gives insight into the disease prevalence, pandemic, epidemiology, pathogenesis, disease transmission, major strategies and steps to be pursued toward controlling cholera.

Meat species identification and Halal authentication analysis using mitochondrial DNA.

A method utilizing PCR-restriction fragment length polymorphism (RFLP) in the mitochondrial genes was developed for beef (Bos taurus), pork (Sus scrofa), buffalo (Bubalus bubali), quail (Coturnix coturnix), chicken (Gallus gallus), goat (Capra hircus), rabbit (Oryctolagus cuniculus) species identification and Halal authentication. PCR products of 359-bp were successfully obtained from the cyt b gene of these six meats. AluI, BsaJI, RsaI, MseI, and BstUI enzymes were identified as potential restriction endonucleases to differentiate the meats. The genetic differences within the cyt b gene among the meat were successfully confirmed by PCR-RFLP. A reliable typing scheme of species which revealed the genetic differences among the species was developed.