Studies on microsporidial infection mostly focus on immunodeficiency or immunosuppressive individuals. Therefore, this cross-sectional study describes the prevalence and risk factors of microsporidiosis among asymptomatic individuals in Malaysia.
Vibrio cholerae is a human pathogen that causes mild to severe diarrheal illnesses and has major public health significance. Herein, we present a thermostabilized electrochemical genosensing assay combining the use of magnetic beads as a biorecognition platform and gold nanoparticles as a hybridization tag for the detection and quantification of V. cholerae lolB gene single-stranded asymmetric PCR amplicons as an alternative to the time-consuming classical isolation method. This thermostabilized, pre-mixed, pre-aliquoted and ready-to-use magnetogenosensing assay simplified the procedures and permitted the reaction to be conducted at room temperature. The asymmetric PCR amplicons were hybridized to a magnetic bead-functionalized capture probe and a fluorescein-labeled detection probe followed by tagging with gold nanoparticles. Electrochemical detection of the chemically dissolved gold nanoparticles was performed using the differential pulse anodic stripping voltammetry method. The real-time stability evaluation of thermostabilized assay was found to be stable for at least 180 days at room temperature (25-30°C). The analytical specificity of the assay was 100%, while its analytical sensitivity was linearly related to different concentrations of 200-mer synthetic target, purified genomic DNA, and bacterial culture with a limit of detection (LoD) of 3.9nM, 5pg/µl, and 10(3)CFU/ml, respectively. The clinical applicability of the assay was successfully validated using spiked stool samples with an average current signal-to-cut-off ratio of 10.8. Overall, the precision of the assay via relative standard deviation was <10%, demonstrating its reliability and accuracy.
Chronic carriers of Salmonella Typhi act as reservoirs for the organism and become the agents of typhoid outbreaks in a community. In this study, chronic carriers in Kelantan, Malaysia were first identified using the culture and polymerase chain reaction method. Then, a novel serological tool, designated Typhidot-C, was evaluated in retrospect using the detected individuals as control positives. Chronic carriage positive by the culture and polymerase chain reaction method was recorded at 3.6% (4 out of 110) among individuals who previously had acute typhoid fever and a 9.4% (10 out of 106) carriage rate was observed among food handlers screened during outbreaks. The Typhidot-C assay was able to detect all these positive carriers showing its potential as a viable carrier screening tool and can be used for efficient detection of typhoid carriers in an endemic area. These findings were used to establish the first carrier registry for S Typhi carriers in Malaysia.
A total of 157 stool samples were examined for Group A rotaviruses in diarrheic children admitted to 8 different major hospitals in Malaysia. The overall incidence rate in this study was 19.7% (31 of 157) with a variation of 9.5% to 39.1% in different locations. Majority of the infections detected were in those under 2 years of age and there were fewer admissions in the older age group. The stool samples were initially screened for rotavirus Group A by latex agglutination method and followed by RNA electrophoresis. The size and the characteristics wheel-shaped morphology of the viral preparations when examined by electron-microscopy further confirmed the presence of rotaviruses in the positive stool samples. Analysis of the RNA pattern showed that majority of the isolates, 51.6% (16 of 31) were Type IIC ('long' with comigration of RNA segments 7 and 8), 35.5% (11 of 31) with Type IIG ('long' with comigration of segments 7, 8, 9), 9.7% (3 of 31) with Type IG ('short' with comigration of RNA segments 7, 8, 9) and 3.2% (1 of 31) of mixed or atypical pattern. It appeared that over a 12 year interval, only one new or unusual rotavirus electropherotype was found. This is the first comprehensive report on the electropherotypes of rotaviruses covering eight different geographical locations in Malaysia and the data obtained is useful for understanding the geographic distribution and types of rotaviruses transmitting in Malaysia.
This pilot study aims to assess Escherichia coli (E. coli) contamination and its perceived health risks among beachgoers in ten tropical beach sands along Port Dickson coastline (Malaysia). This study also aims to determine the relationship between perceived health symptoms and tropical beach sand exposure behavior. The concentration of E. coli in tropical beach sand ranged from 60cfu/100g to 4113cfu/100g. E. coli contamination was the highest at Tanjung Gemuk (4113±30cfu/100g) and the lowest at Tanjung Tuan (60±15cfu/100g); the high level of contamination could be due to the location of the former at the sewage outlet of nearby hotels. Skin symptoms were the most predominant among the health symptoms indicated by beachgoers. Exposure duration was significantly correlated with the perceived health symptoms among beachgoers in the beaches studied.
Fifty samples of chicken, duck and geese faeces were obtained from 13 wet markets in Kuala Lumpur to study the prevalence of vancomycin-resistant enterococci (VRE) among local market poultry. Biotyping of colonies grown on azide agar incubated at 45 degrees C yielded E. pseudoavium, E. faecalis, E. faecium and E. gallinarum from chicken faeces and E. malodoratus, E. faecalis, E. faecium, E. gallinarum, E. hirae/dispar, and E. durans from goose and duck faeces. On agar containing 6 mg/ l of vancomycin, one strain of E. flavescens was identified, giving a VRE detection rate of 2.0%. This isolate had a vancomycin M.I.C. of 8 mg/l as determined by the Etest, and the van C-3 gene that was identified by PCR followed by sequence analysis. The prevalence of VRE among poultry sold in local markets appears to be low, and may reflect the infrequent use of antimicrobials in our poultry farms. Nevertheless, the possibility of human acquisition of microbes via the food chain cautions against the use of antimicrobials in animal husbandry that may encourage the emergence and spread of multi-drug resistant organisms like the VRE among animal microbial flora.
A representative sample of 20 isolates of Salmonella weltevreden strains from stool cultures of patients admitted at the University Hospital, Kuala Lumpur, Malaysia were analyzed. All the strains were susceptible to ampicillin, ceftriaxone, ciprofloxacin, chloramphenicol, tetracycline, trimethoprim, gentamicin and co-trimoxazole. Ribosomal RNA gene restriction pattern analysis of PstI-digested DNA gave three ribotypes while pulsed-field gel electrophoresis (PFGE) analysis of XbaI-digested DNA gave ten distinct profiles. PFGE was more discriminative than ribotyping in distinguishing the strains. The majority of the strains analyzed were very closely related with similarity coefficient values ranging from 0.8 to 1.0. Both PFGE and ribotyping could distinguish one of the strains which was obtained from a patient following a bone marrow transplant for beta-thalassemia major, indicating that this particular strain was unrelated to the rest of the strains from patients with acute gastroenteritis.
The group A rotavirus staphylococcal co-agglutination test was evaluated and its sensitivity and specificity compared with an in-house enzyme-linked immunosorbent assay (ELISA) and a commercial latex agglutination test (Rotalex). In addition, the storage stability of the staphylococcal reagents was ascertained. Examination of 136 clarified suspensions of diarrhoeal faeces by the staphylococcal co-agglutination test revealed a high proportion of false positives (26%) and uninterpretable results (34%) due to non-specific agglutination. Non-specific agglutination could be removed effectively by prior absorption of the clarified faecal specimens with unsensitized staphylococci. The staphylococcal co-agglutination test was less sensitive and specific than the in-house enzyme-linked immunosorbent assay but was comparable to the Rotalex slide latex agglutination test. The staphylococcal reagents have a shelf life of at least 29 weeks.
A 57-year-old man, while on travel in Malaysia, suffered from diarrhea after he ate fruits. He developed limbs weakness without sensory disturbance after his return to Japan. Serum from the patient had high IgG anti-GM1 antibody titer. Campylobacter jejuni was isolated from his stool. The serotype belonged to PEN 5. The patient received double-filtration plasmapheresis 7 times during from days 6 to 17. Muscle strength began to recover gradually on day 10, and returned to normal 5 months after the onset of neurologic symptoms. Repeated neurophysiologic studies indicated that the axonal degeneration of motor nerves was predominant process. This case suggests that Guillain-Barré syndrome is a complication of traveler's diarrhea.
Isolates of anaerobic fungi obtained from the rumen, duodenum and faeces of sheep were identified as Piromyces mae based on their morphological characteristics observed using light microscopy. There was no significant morphological variation among the isolates of P. mae from the rumen, duodenum and faeces. Isozymes of 12 isolates of P. mae (one each from the rumen, duodenum and faeces from 4 different sheep) were analysed by PAGE. A total of 12 isozymes were studied and 5 isozyme loci were successfully typed. They were malic enzyme, malate dehydrogenase, shikimate dehydrogenase, alpha-esterase and beta-esterase. All the isolates of P. mae regardless of whether they were from the rumen, duodenum or faeces or from different animals produced very similar isozyme banding patterns for each of the enzyme systems. The similar isozyme profiles of the isolates indicate that they are of the same species although they exist in different regions of the alimentary tract.
We performed genome size estimation of 17 recent human isolates of Salmonella typhi from geographically diverse regions using pulsed-field gel electrophoresis (PFGE) after digestion of chromosomal DNA with restriction endonucleases XbaI (5'-TCTAGA-3'), AvrII (5'-CCTAGG-3') and SpeI (5'-ACTAGT-3'), and summation of the sizes of restriction fragments obtained. All 17 isolates had circular chromosomes, and genome sizes differed by as much as 959 kb, ranging from 3,964 to 4,923 kb (mean genome size = 4,528 kb). The data obtained confirm the usefulness of PFGE in studies of bacterial genome size and are in agreement with recent results indicating considerable genetic diversity and genomic plasticity of S. typhi. The variation in genome sizes noted may be relevant to the observed biological properties of this important human pathogen, including its virulence.
The first case report of Yersinia enterocolitica infection in Malaysia is presented. The patient was a 34-year-old Indian woman who had a four day history of fever, abdominal pain and cough and loose stools for 2 days. She was diagnosed and treated as a case, initially of bacillary dysentery, and then of urban typhus. She responded to tetracycline therapy. Bacteriological examination eventually resulted in the isolation and identification of Yersinia enterocolitica, serotype 0:3. This case indicates the presence of the infection in Malaysia although the incidence is probably very low. This appears to be the situation in 'warm' countries.
Enterotoxin production by strains of Staphylococcus aureus isolated from human, food and animal sources was investigated. Of the 130 isolates studied, 27 (20.8%) were found to be enterotoxigenic. The most common enterotoxin detected from human sources was enterotoxin C whereas enterotoxin B occurred more frequently in staphylococcal strains of food origin. The 2 enterotoxigenic strains, from animals isolated from a dog and a goat, produced enterotoxins A and C, respectively. Enterotoxin E was not detected alone from any of the enterotoxigenic strains studied, but occurred together with other enterotoxins. The need to detect enterotoxin in staphylococcal strains and in suspected foods for the confirmation of staphylococcal food poisoning is discussed.
Four strains of S. typhi isolated in Malaysia were found to show resistance to chloramphenicol and other antibiotics. In two of these strains it was possible to show that this resistance was transferable.
This problem which is widespread in neighbouring countries and undetected in Malaysia till recently has now been shown to exist in this country. Fears that the incidence of such strains will increase in the future are expressed and the need for vigilance is emphasised.
There is an increasing trend for Shigella isolates worldwide to be resistant to commonly prescribed antibiotics. The species distribution and antibiotic resistance of Shigella species isolated from children in Kuala Lumpur, Malaysia from 1978 to 1997 was reviewed. Three hundred and eighty six isolates were positive for Shigella species, representing 1.4% (95% CI: 1.3%-1.6%) of the 26320 total stool specimens and 13% (95% CI: 11.8%-14.2%) of 2986 isolates positive for bacterial pathogens. Shigella flexneri, constituting 74% of all isolates in the first five years of the study, decreased by 40% during the last five years (95% CI of decrease: 22.1%-57.9%), p-value < 0.0001) to 34%. There was a significant reduction (chi2 for linear trend = 77.6, p-value < 0.001) in the number of Shigella isolates as a percentage of total stool isolates obtained. 58% of the 241 isolates tested for antibiotic sensitivity were resistant to at least one antibiotic, and 42% wEre multi-resistant to three or more antibiotics. Shigella species was not a common pathogen among children admitted with diarrhoea in Kuala Lumpur, and was more likely to be resistant to commonly prescribed antibiotics.