ABSTRACT
@#Background: Streptococcus pyogenes has a variety of virulence factors and the predominant invasive strains differ according to specific emm types and geographical orientation. Although emm typing is commonly used as the gold standard method for the molecular characterisation, multilocus sequence typing (MLST) has become an important tool for comparing the genetic profiles globally. This study aimed to screen selected virulence genes from invasive and non-invasive clinical samples and to characterise the molecular epidemiology by emm typing and MLST methods. Materials and Methods: A total of 42 S. pyogenes isolates from invasive and non-invasive samples collected from two different tertiary hospitals were investigated for the distribution of virulence factors and their molecular epidemiology by emm and multilocus sequence typing methods. Detection of five virulence genes (speA, speB, speJ, ssa and sdaB) was performed using multiplex polymerase chain reaction (PCR) using the standard primers and established protocol. Phylogenetic tree branches were constructed from sequence analysis utilised by neighbour joining method generated from seven housekeeping genes using MEGA X software. Results: Multiplex PCR analysis revealed that sdaB/speF (78.6%) and speB (61.9%) were the predominant virulence genes. Regardless of the type of invasiveness, diverse distribution of emm types/subtypes was noted which comprised of 27 different emm types/subtypes. The predominant emm types/subtypes were emm63 and emm18 with each gene accounted for 11.8% whereas 12% for each gene was noted for emm28, emm97.4 and emm91. The MLST revealed that the main sequence type (ST) in invasive samples was ST402 (17.7%) while ST473 and ST318 (12% for each ST) were the major types in non-invasive samples. Out of 18 virulotypes, Virulotype A (five genes, 55.6%) and Virulotype B (two genes, 27.8%) were the major virulotypes found in this study. Phylogenetic analysis indicated the presence of seven different clusters of S. pyogenes. Interestingly, Cluster VI showed that selected emm/ST types such as emm71/ST318 (n=2), emm70.1/ST318 (n=1), emm44/ST31 (n=1) and emm18/ST442 (n=1) have clustered within a common group (Virulotype A) for both hospitals studied. Conclusion: The present study showed that group A streptococcci (GAS) are genetically diverse and possess virulence genes regardless of their invasiveness. Majority of the GAS exhibited no restricted pattern of virulotypes except for a few distinct clusters. Therefore, it can be concluded that virulotyping is partially useful for characterising a heterogeneous population of GAS in hospitals.
ABSTRACT
@#Hepatitis B (HB) is an upcoming health issue in Malaysia. Even though the Expanded Programme on Immunisation (EPI) for HB vaccination implemented by the Malaysia government in 1989, individuals born before 1989 were not covered under the EPI and should immunised against the HB virus. Examining the Malaysians’ perception of vaccination is very important in order to determine their behaviour regarding HB vaccination. Most of the studies only gave priority to analysing this issue from an occupational risk perspective, consumers’ perceptions of the HB vaccination are still lacking. This study is aimed at assessing the validity and reliability of the Malay version of the perception questionnaire used for Malaysian households. A pilot study involving 300 respondents was conducted in six districts in the Selangor area. Factor analysis constructed four components: perceived sustainability, perceived severity, perceived benefit and perceived barriers loaded on the corresponding component with factor loading of more than 0.5. Principal component analysis of the finalised 13 items explained the instrument of the variance, which was 59.7% in total, 20.3%, 14.5%, 12.5% and 12.4% explained by the four constructs. The Cronbach alpha for the items instruments is 0.5 to 0.8 which shows that moderate internal consistency exists and demonstrates reliability of the questionnaire. The frequency of the four constructs shows that most of the respondents worry about getting infected with HBV, the perceived severity level is high among respondents, they perceived benefit from getting an HB vaccination and perceived low barriers to getting the HB vaccination.
ABSTRACT
@#Introduction: Immune reconstitution inflammatory syndrome (IRIS) is paradoxical clinical deterioration experienced by some HIV-infected patients in response to antiretroviral therapy (ART). There is still limited published data on IRIS from this region including Malaysia. This study aimed to determine IRIS prevalence, clinical manifestations and possible predictors among HIV-infected patients in an infectious disease centre in Peninsular Malaysia. Method: This retrospective study was conducted in Hospital Sungai Buloh involving secondary data of 256 HIV-infected patients who were initiated on ART in the year 2017. Medical record of each patient was reviewed for up to 12 months following ART initiation to identify IRIS diagnosis which was made by the treating physician. Relevant clinical and laboratory information were retrieved from hospital electronic database. Results: IRIS has occurred in 17.6% of patients. Infections by Mycobacterium tuberculosis (53.3%), Pneumocystis jirovecii (11.1%) and Talaromyces marneffei (6.6%) were the commonest three aetiologies of IRIS. Subacute lupus erythematosus was the only non-infectious IRIS identified. Baseline HIV viral load, CD4+ T-cell count and haemoglobin level between IRIS and non-IRIS patients were significantly different. Risk of developing IRIS was increased seven times in patients with CD4+ T-cell count < 100 cells/µL and four times in patients with HIV RNA viral load > 5.5 log10 copies/ml prior to ART initiation. Conclusion: Mycobacterium tuberculosis infections were the highest IRIS manifestation. Although rare, non-infectious IRIS does occur and should be part of the differential diagnosis. Patients with positive predictors should be appropriately monitored for possible IRIS development once initiated on ART.
ABSTRACT
The in vitro activities of 6 antimicrobial agents against clinical isolates of Streptococcus pneumoniae (pneumococci) were investigated and the erythromycin minimum inhibitory concentrations (MICs) were correlated with the two major macrolide resistance determinants, mef(A) and erm(B). MICs of commonly used antibiotics as well as the presence of macrolide resistance determinant genes in all isolates were tested. Seventy one pneumococcal isolates collected at Institute for Medical Research (IMR) were included in this study. Phenotypic characterization, MIC determination using E-test strips and polymerase chain reactions for antibiotic resistance determination were included. Among the isolates, 25 (35.2%) isolates were erythromycin susceptible, 3 (4.2%) were intermediate and 42 (60.6%) were resistant. Fifty three isolates (74.7%) were found with mef(A) alone, 15 (21.1%) isolates with erm(B) + mef(A) combination and 3 (4.2%) isolates with none of the two genes. The in vitro activity of penicillin, amoxicillin clavulanic acid, ceftriaxone and cefotaxime is superior to trimethoprim-sulfamethoxazole and erythromycin. In conclusion, pneumococcal isolates in this study were highly susceptible to penicillin with very low MICs. However, a very high prevalence rate of erythromycin resistance was observed. Erythromycin resistant S.pneumoniae isolates with both mef(A) and erm(B) showed very high MICs ≥256 μg/mL.