New modular platform based on multi-adjuvanted amphiphilic chitosan nanoparticles for efficient lipopeptide vaccine delivery against group A streptococcus

An effective vaccine against group A streptococcus(GAS)is highly desirable for definitive control of GAS infections.In the present study,two variants of amphiphilic chitosan nanoparticles-based GAS vaccines were developed.The vaccines were primarily composed of encapsulated KLH protein(a source of T helper cell epitopes)and lipidated M-protein derived B cell peptide epitope(lipoJ14)within the amphiphilic structure of nanoparticles.The only difference between themwas one of the nanoparticles vaccines received additional surface coating with poly(I:C).The formulated vaccines exhibited nanosized particles within the range of 220–240 nm.Cellular uptake study showed that nanoparticles vaccine without additional poly(I:C)coating has greater uptake by dendritic cells and macrophages compared to nanoparticles vaccine that was functionalized with poly(I:C).Both vaccines were found to be safe in mice and showed negligible cytotoxicity against HEK293 cells.Upon immunization in mice,both nanoparticle vaccines produced high antigen-specific antibodies titres that were regulated by a balanced Th1 and Th2 response compared to physical mixture.These antibodies elicited high opsonic activity against the tested GAS strains.Overall,our data demonstrated that amphiphilic chitosan nanoparticles platform induced a potent immune response even without additional inclusion of poly(I:C).

Disseminated strongyloidiasis in an immunocompromised host:A case report

Infections caused by Strongyloides stercoralis(S.stercoralis) in human are generally asymptomatic,however in immunocompromised individual,hyperinfection may develop with dissemination of larvae to extra-intestinal organs.The diagnosis could be easily missed due to asymptomatic presentation and insufficient exposure towards the infection itself,which may lead to low index of suspicion as a consequence.In this report,a case of a Malaysian male with underlying diabetes mellitus,hypertension,cerebrovascular accident,bullous pemphigus and syndrome of inappropriate antidiuretic hormone secretion who initially complained of generalized body weakness and poor appetite without any history suggestive of sepsis is presented.However,he developed septicemic shock later,and S.stercoralis larvae was incidentally found in the tracheal aspirate that was sent to look for acid fast bacilli.Regardless of aggressive resuscitation,the patient succumbed due to pulmonary hemorrhage and acute respiratory distress syndrome.It was revealed that the current case has alarmed us via incidental finding of S.stercoralis larvae in the tracheal aspirate,indicating that the importance of the disease should be emphasized in certain parts of the world and population respectively.

Prevalence and risk factors of Blastocystis infection among underprivileged communities in rural Malaysia

Objective:To determine the prevalence and risk factors of Blastocystis among underprivileged communities living in rural Malaysia. Methods:This cross-sectional study was conducted among 253 participants aged between 1 and 85 years. Stool samples were examined using Wheatley's trichrome stain after in-vitro cultivation in Jones' medium to detect the presence of Blastocystis. Information pertaining to the demography,socioeconomic and environment were collected using pre-validated questionnaires. Results:The total prevalence of Blastocystis infection was 40.7%. The multiple logistic regression analysis revealed that age ≥15 years(OR = 2.72; 95%CI = 1.47-5.04) and presence of infected family members(OR = 8.56; 95%CI = 4.47-16.38) were the significant risk factors associated with blastocystosis in these communities. Conclusions:Blastocystosis is revealed through this study to be still prevalent among Orang Asli communities in rural Malaysia. The two main approaches that should be implemented by the public health authority in battling this infection would be the screening of other family members and giving treatment to the infected individuals. Moreover,it is imperative for health education on good personal and food hygiene practices are provided in order to reduce the morbidity and transmission of Blastocystis infection among the Orang Asli in their communities meaningfully.

Impact of seasonality on the prevalence and risk factors of Giardia lamblia infections among the aborigines

Objective: To determine the prevalence and risk factors of Giardia(G.) lamblia infections among the aboriginal community during the wet and dry seasons. Methods: A total of 473 stool samples from the aborigines in Temerloh, Pahang, Malaysia were collected during wet(n=256) and dry seasons(n=217). Smear of all the PVA-preserved stool samples were subjected to Trichrome staining and microscopic examination under 1 000 伊magnification(Nikon eclipse E100) for the detection of G. lamblia. Positivity was recorded based on the presence of G. lamblia in trophozoite and/or cyst forms. Results: The prevalence of giardiasis was 12.10% and 8.29% during the wet and dry season, respectively. Age of less or equal to 15 years old and presence of other family members with G. lamblia infection were found to be the significant risk factors to acquire G. lamblia infections during both seasons. Untreated water supply was the significant risk factor of giardiasis during the dry season. This study highlighted the possibility of anthroponotic transmission of G. lamblia during both seasons and waterborne transmission during the dry season in the aboriginal community. Conclusions: This study suggests that seasonal variation plays an important role in the prevalence and risk factor of G. lamblia infection in the aboriginal community. Therefore, close contact with Giardia-infected family members and water-related activities or usage of untreated water must be avoided to reduce the burden of G. lamblia infection in this community.

Morphological and molecular characterization of Acanthamoeba isolatedfrom contact lens paraphernalia in Malaysia: Highlighting the pathogenicpotential of T4 genotype

Objective:To determine the morphological and molecular characterization of Acanthamoeba isolates from contact lens paraphernalia in Malaysia and to investigate their pathogenic potential based on the physiological tolerance.Methods:One hundred and eighty contact lens wearers donated their contact lens,lens storage cases and lens solutions between2018 and 2019.The samples were inoculated onto 1.5%nonnutrient agar plates for 14 d.Polymerase chain reaction(PCR)was performed and the amplified PCR products were sequenced and compared with the published sequences in GenBank.The pathogenic potential of positive isolates was further tested using temperature-tolerance and osmo-tolerance assays.Acanthamoeba species were categorized into three distinct morphological groups established by Pussard and Pons.Results:Acanthamoeba was successfully isolated from 14(7.8%)culture-positive samples in which 11 belong to morphological groupⅡand 3 belong to morphological groupⅢ,respectively.The sequencing of 18 S ribosomal RNA gene led to the identification of the T4 genotype in all the isolated strains.In vitro assays revealed that 9(64.3%)Acanthamoeba isolates were able to grow at 42℃and 1 M mannitol and were thus considered to be highly pathogenic.Conclusions:To the best of our knowledge,this is the first report identifying the Acanthamoeba genotype and their pathogenic potential among contact lens wearers in Malaysia.The potentially pathogenic T4 genotype isolated in this study is the most predominant genotype responsible for human ocular infection worldwide.Hence,increasing attention should be aimed at the prevention of contamination by Acanthamoeba and the disinfection of contact lens paraphernalia.