Displaying publications 61 - 80 of 289 in total

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  1. Herbal hydrogel-based encapsulated Enterococcus faecium ABRIINW.N7 improves the resistance of red hybrid tilapia against Streptococcus iniae
    Kahieshesfandiari M, Nami Y, Lornezhad G, Kiani A, Javanmard A, Jaymand M, et al.
    J Appl Microbiol, 2021 Nov;131(5):2516-2527.
    PMID: 33817937 DOI: 10.1111/jam.15098
    AIMS: The streptococcal disease has been associated with serious mortality and significant global economic loss in the tilapia farming industry. The overall goal of this work was to test herbal hydrogels based on encapsulated Enterococcus faecium ABRIINW.N7 for potential probiotic anti-microbial activity against Streptococcus iniae in red hybrid tilapia.

    METHODS AND RESULTS: Abnormal behaviour, clinical signs, postinjection survival and histopathology (kidney, liver, eye and brain) were measured. Cumulative mortality of CON+ , free cells, ALG and treatments (F1-F7) was 30, 24, 22, 19, 17, 17, 16, 14, 14 and 12 out of 30 fish and the survival rates for E. faecium ABRIINW.N7 microencapsulated in an alginate-BS blend with 0·5, 1, 1·5, 2, 2·5 and 3% fenugreek were 43, 43, 47, 53, 53 and 60%, respectively. After the incorporation of fenugreek with the alginate-BS blend, there was an 8-21% increase in probiotic cell viability. Furthermore, the survival rate for the alginate-BS blend with 2·5 and 3% fenugreek (F6 and F7) was significantly (P ≤ 0·05) higher than other blends. The highest encapsulation efficiency, viability in gastrointestinal conditions and during storage time and excellent antipathogenicity against S. iniae were observed in alginate-BS +3% fenugreek formulation (F7).

    CONCLUSIONS: It is recommended that probiotic strains like E. faecium ABRIINW.N7 in combination with local herbal gums, such as BS and fenugreek plus alginate, can be used as a suitable scaffold and an ideal matrix for the encapsulation of probiotics.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This study proposes models connecting process parameters, matrix structure and functionality.

    Matched MeSH terms: Streptococcus iniae
  2. Fulltext New emm (M protein gene) sequences of group A streptococci isolated from Malaysian patients
    Jamal F, Pit S, Facklam R, Beall B
    Emerg Infect Dis, 1999 Jan-Feb;5(1):182-3.
    PMID: 10081694
    Matched MeSH terms: Streptococcus pyogenes/classification; Streptococcus pyogenes/genetics*; Streptococcus pyogenes/isolation & purification
  3. Fulltext Enhanced production, purification, characterization and mechanism of action of salivaricin 9 lantibiotic produced by Streptococcus salivarius NU10
    Barbour A, Philip K, Muniandy S
    PLoS One, 2013;8(10):e77751.
    PMID: 24147072 DOI: 10.1371/journal.pone.0077751
    BACKGROUND: Lantibiotics are small lanthionine-containing bacteriocins produced by lactic acid bacteria. Salivaricin 9 is a newly discovered lantibiotic produced by Streptococcus salivarius. In this study we present the mechanism of action of salivaricin 9 and some of its properties. Also we developed new methods to produce and purify the lantibiotic from strain NU10.

    METHODOLOGY/PRINCIPAL FINDINGS: Salivaricin 9 was found to be auto-regulated when an induction assay was applied and this finding was used to develop a successful salivaricin 9 production system in liquid medium. A combination of XAD-16 and cation exchange chromatography was used to purify the secondary metabolite which was shown to have a molecular weight of approximately 3000 Da by SDS-PAGE. MALDI-TOF MS analysis indicated the presence of salivaricin 9, a 2560 Da lantibiotic. Salivaricin 9 is a bactericidal molecule targeting the cytoplasmic membrane of sensitive cells. The membrane permeabilization assay showed that salivaricin 9 penetrated the cytoplasmic membrane and induced pore formation which resulted in cell death. The morphological changes of test bacterial strains incubated with salivaricin 9 were visualized using Scanning Electron Microscopy which confirmed a pore forming mechanism of inhibition. Salivaricin 9 retained biological stability when exposed to high temperature (90-100°C) and stayed bioactive at pH ranging 2 to 10. When treated with proteinase K or peptidase, salivaricin 9 lost all antimicrobial activity, while it remained active when treated with lyticase, catalase and certain detergents.

    CONCLUSION: The mechanism of antimicrobial action of a newly discovered lantibiotic salivaricin 9 was elucidated in this study. Salivaricin 9 penetrated the cytoplasmic membrane of its targeted cells and induced pore formation. This project has given new insights on lantibiotic peptides produced by S. salivarius isolated from the oral cavities of Malaysian subjects.

    Matched MeSH terms: Streptococcus/metabolism*; Streptococcus/physiology
  4. Fulltext Capsular serotype and antibiotic resistance of Streptococcus pneumoniae isolates in Malaysia
    Le CF, Palanisamy NK, Mohd Yusof MY, Sekaran SD
    PLoS One, 2011;6(5):e19547.
    PMID: 21603602 DOI: 10.1371/journal.pone.0019547
    BACKGROUND: Streptococcus pneumoniae is a major causative agent of severe infections, including sepsis, pneumonia, meningitis, and otitis media, that has since become a major public health concern. In this study, the serotypes distribution of pneumococcal isolates was investigated to predict the efficacy of the 7-valent pneumococcal conjugate vaccine (PCV7) among the Malaysian populations.
    METHODOLOGY/PRINCIPAL FINDINGS: A total of 151 clinical isolates were serotyped using multiplex PCR assays. Out of them, there were 21.2% penicillin-resistant, 29.1% penicillin-intermediate, and 49.7% penicillin-susceptible S. pneumoniae strains. Serotypes detected among the Malaysian isolates were 1, 3, 10A, 11A/11D, 12F/12A, 14, 15A, 15B/15C, 16F, 18C/18B/18A/18F, 19A, 19F, 23F, 35B, 35F/47F, 6A/6B, 7C/7B/40, 7F/7A, 9V/9A, and 34. Serotype 19F and 23F were the two most prevalent serotypes detected. Serotypes are highly associated with invasiveness of isolates (p = 0.001) and penicillin susceptibility (p<0.001). Serotype 19F was observed to have increased resistance against penicillin while serotype 19A has high invasive tendency. Age of patients was an important factor underlying the pneumococcal serotypes (p = 0.03) and clinical sites of infections (p<0.001). High prevalence of pneumococcal isolates were detected among children <5 years old at nasopharyngeal sites while elderly adults ≥60 years old were at increased risk for pneumococcal bacteremia.
    CONCLUSION/SIGNIFICANCE: Current study revealed that a number of serotypes, especially those associated with high penicillin resistance, have been formulated in the PCV7. Therefore, the protections expected from the routine use of PCV7 would be encouraging for the Malaysian. However, it is not possible to predict serotypes that might become predominant in the future and hence continued surveillance of circulating serotypes will be needed.
    Matched MeSH terms: Streptococcus pneumoniae/drug effects*; Streptococcus pneumoniae/isolation & purification
  5. Serotype distribution and antibiotic susceptibility of group B streptococci in pregnant women
    Dhanoa A, Karunakaran R, Puthucheary SD
    Epidemiol Infect, 2010 Jul;138(7):979-81.
    PMID: 19889253 DOI: 10.1017/S0950268809991105
    Group B streptococcus (GBS) is a leading cause of neonatal sepsis and is usually acquired via the woman's birth canal. GBS serotypes isolated from 200 pregnant women were determined. Serotypes V (19%) and VI (17%) were the most frequent followed by serotypes III (12%), Ia (11.5%) and IV (10%); 17% of the strains were non-typable. All isolates were susceptible to penicillin, 96% to erythromycin and 97.5% to clindamycin. The emergence of new GBS serotypes has important implications for vaccine prevention strategies.
    Matched MeSH terms: Streptococcus agalactiae/classification*; Streptococcus agalactiae/drug effects*
  6. In-vitro susceptibilities of Streptococcus pneumoniae strains isolated in Malaysia to six antibiotics
    Rohani MY, Parasakthi N, Raudzah A, Yasim MY
    J Antimicrob Chemother, 1999 Dec;44(6):852-3.
    PMID: 10590295
    Matched MeSH terms: Streptococcus pneumoniae/drug effects*; Streptococcus pneumoniae/isolation & purification
  7. Antimicrobial resistance in Streptococcus pneumoniae: an overview
    Appelbaum PC
    Clin Infect Dis, 1992 Jul;15(1):77-83.
    PMID: 1617076
    Clinical resistance to penicillin in Streptococcus pneumoniae was first reported by researchers in Boston in 1965; subsequently, this phenomenon was reported from Australia (1967) and South Africa (1977). Since these early reports, penicillin resistance has been encountered with increasing frequency in strains of S. pneumoniae from around the world. In South Africa strains resistant to penicillin and chloramphenicol as well as multiresistant strains have been isolated. Similar patterns of resistance have been reported from Spain. Preliminary evidence points to a high prevalence of resistant pneumococci in Hungary, other countries of Eastern Europe, and some countries in other areas of Europe, notably France. In the United States most reports of resistant pneumococci come from Alaska and the South, but resistance is increasing in other states and in Canada. Pneumococcal resistance has also been described in Zambia, Japan, Malaysia, Pakistan, Bangladesh, Chile, and Brazil; information from other African, Asian, and South American countries is not available. The rising prevalence of penicillin-resistant pneumococci worldwide mandates selective susceptibility testing and epidemiological investigations during outbreaks.
    Matched MeSH terms: Streptococcus pneumoniae/classification; Streptococcus pneumoniae/drug effects*
  8. Distribution of group B streptococcal serotypes in Malaysia
    Ngeow YF, Puthucheary SD
    J Trop Med Hyg, 1987 Aug;90(4):193-6.
    PMID: 3309355
    A total of 350 strains of group B streptococci (308 from adults and 42 from neonates) were serotyped. The majority of the isolates from adult patients were from the genito-urinary tract and most of the neonatal isolates were from babies less than 10 days old. Serotype III was the predominant type among all groups of patients and accounted for 50.9% of all serotypes. The second and third most frequently occurring serotypes were II and Ic respectively. Together with type III they made up 87% of the isolates.
    Matched MeSH terms: Streptococcus agalactiae/classification*; Streptococcus agalactiae/isolation & purification
  9. Effectiveness of ultrasonic files in the disruption of root canal bacteria
    Ahmad M, Pitt Ford TR, Crum LA, Wilson RF
    Oral Surg. Oral Med. Oral Pathol., 1990 Sep;70(3):328-32.
    PMID: 2216361
    The physical mechanisms of ultrasound, namely cavitation and acoustic streaming, generated by the Enac-Osada ultrasonic unit were investigated for effectiveness in disrupting Streptococcus mitis. In addition, the bactericidal effect of ultrasound in the presence of 2.5% sodium hypochlorite was examined. Bacterial suspensions were irradiated directly with ultrasound in simulated root canals, and the viability of bacteria was examined after growth on a blood agar medium under anaerobic conditions at 37 degrees C for 5 days. The results indicated that ultrasound per se failed to disrupt bacteria but resulted in increases in the viable counts; the former was considered to be because of the lack of cavitation and the latter because of the dispersal effects of acoustic streaming. The 2.5% sodium hypochlorite solution demonstrated powerful bactericidal activity.
    Matched MeSH terms: Streptococcus/drug effects; Streptococcus/radiation effects*
  10. A study of haemolytic streptococci isolated from outpatients in dermatological clinics
    Murai T, Inazumi Y, Nishiwaki M, Noda Y, Hino H
    Kansenshogaku Zasshi, 1991 Aug;65(8):960-9.
    PMID: 1919131
    A total of 44 patients suspected of streptococcal infections were studied in outpatient clinics in Tokyo during the one year from December 1988 to December 1989. Employing bacteriological culturing and serodiagnosis, the following results were obtained. 1) There were 9 cases of impetigo and 15 cases of erysipelas with typical clinical manifestations and age distributions. 2) It seemed that some of the skin infections were caused by group A streptococci whose M-types were different from those of upper respiratory infections typically occurring in Japan. 3) The type distribution of group A streptococci found were quite similar to those isolated in Thailand or Malaysia. 4) There were found group A streptococci exhibiting unique combinations of T- and M-types, such as T11 and M9, T11 and M62 or T13-49 and MOD8 (Provisional type). 5) As for serodiagnostic method, ADNB (anti-deoxyribonuclease B) titer reflected infection by group A streptococcus only, while ASK (anti-streptokinase) and ASO (anti-streptolysin O) reflected not only group A streptococcal infections but group G infections as well.
    Matched MeSH terms: Streptococcus pyogenes/classification*; Streptococcus pyogenes/immunology
  11. Fulltext Composition and Antibacterial Activity of the Essential Oils of Orthosiphon stamineus Benth and Ficus deltoidea Jack against Pathogenic Oral Bacteria
    Azizan N, Mohd Said S, Zainal Abidin Z, Jantan I
    Molecules, 2017 Dec 05;22(12).
    PMID: 29206142 DOI: 10.3390/molecules22122135
    In this study, the essential oils of Orthosiphon stamineus Benth and Ficus deltoidea Jack were evaluated for their antibacterial activity against invasive oral pathogens, namely Enterococcus faecalis, Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Fusobacterium nucleatum. Chemical composition of the oils was analyzed using gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The antibacterial activity of the oils and their major constituents were investigated using the broth microdilution method (minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC)). Susceptibility test, anti-adhesion, anti-biofilm, checkerboard and time-kill assays were also carried out. Physiological changes of the bacterial cells after exposure to the oils were observed under the field emission scanning electron microscope (FESEM). O. stamineus and F. deltoidea oils mainly consisted of sesquiterpenoids (44.6% and 60.9%, respectively), and β-caryophyllene was the most abundant compound in both oils (26.3% and 36.3%, respectively). Other compounds present in O. stamineus were α-humulene (5.1%) and eugenol (8.1%), while α-humulene (5.5%) and germacrene D (7.7%) were dominant in F. deltoidea. The oils of both plants showed moderate to strong inhibition against all tested bacteria with MIC and MBC values ranging 0.63-2.5 mg/mL. However, none showed any inhibition on monospecies biofilms. The time-kill assay showed that combination of both oils with amoxicillin at concentrations of 1× and 2× MIC values demonstrated additive antibacterial effect. The FESEM study showed that both oils produced significant alterations on the cells of Gram-negative bacteria as they became pleomorphic and lysed. In conclusion, the study indicated that the oils of O. stamineus and F. deltoidea possessed moderate to strong antibacterial properties against the seven strains pathogenic oral bacteria and may have caused disturbances of membrane structure or cell wall of the bacteria.
    Matched MeSH terms: Streptococcus mutans/drug effects; Streptococcus mutans/growth & development; Streptococcus mutans/isolation & purification; Streptococcus mitis/drug effects; Streptococcus mitis/growth & development; Streptococcus mitis/isolation & purification; Streptococcus salivarius/drug effects; Streptococcus salivarius/growth & development; Streptococcus salivarius/isolation & purification
  12. Fulltext Comparative genomic analysis of ten clinical Streptococcus pneumoniae collected from a Malaysian hospital reveal 31 new unique drug-resistant SNPs using whole genome sequencing
    Jindal HM, Ramanathan B, Le CF, Gudimella R, Razali R, Manikam R, et al.
    J Biomed Sci, 2018 Feb 15;25(1):15.
    PMID: 29448938 DOI: 10.1186/s12929-018-0414-8
    BACKGROUND: Streptococcus pneumoniae or pneumococcus is a leading cause of morbidity and mortality worldwide, specifically in relation to community-acquired pneumonia. Due to the overuse of antibiotics, S. pneumoniae has developed a high degree of resistance to a wide range of antibacterial drugs.

    METHODS: In this study, whole genome sequencing (WGS) was performed for 10 clinical strains of S. pneumoniae with different levels of sensitivity to standard antibiotics. The main objective was to investigate genetic changes associated with antibiotic resistance in S. pneumoniae.

    RESULTS: Our results showed that resistant isolates contain a higher number of non-synonymous single nucleotide polymorphisms (SNPs) as compared to susceptible isolates. We were able to identify SNPs that alter a single amino acid in many genes involved in virulence and capsular polysaccharide synthesis. In addition, 90 SNPs were only presented in the resistant isolates, and 31 SNPs were unique and had not been previously reported, suggesting that these unique SNPs could play a key role in altering the level of resistance to different antibiotics.

    CONCLUSION: Whole genome sequencing is a powerful tool for comparing the full genome of multiple isolates, especially those closely related, and for analysing the variations found within antibiotic resistance genes that lead to differences in antibiotic sensitivity. We were able to identify specific mutations within virulence genes related to resistant isolates. These findings could provide insights into understanding the role of single nucleotide mutants in conferring drug resistance.

    Study site: University Malaya Medical Centre (UMMC)
    Matched MeSH terms: Streptococcus pneumoniae/genetics*; Streptococcus pneumoniae/isolation & purification
  13. Chemical composition, antifungal, antibiofilm, and molecular docking studies of Syzygium dyerianum essential oil
    Rahim FAM, Salleh WMNHW, Arzmi MH, Salihu AS
    Z Naturforsch C J Biosci, 2024 Jul 26;79(7-8):179-186.
    PMID: 38454808 DOI: 10.1515/znc-2023-0133
    The current study describes the chemical composition, antifungal, antibiofilm, antibacterial and molecular docking studies of Syzygium dyerianum growing in Malaysia. The essential oil was obtained through hydrodistillation and characterized using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The antifungal and antibacterial activities were developed using the broth microdilution assay, whereas the effect on the microbial biofilms was determined using a semi-quantitative static biofilm assay. A total of 31 components were identified, which represent 99.5 % of the essential oil. The results revealed that the essential oil consisted mainly of β-pinene (15.6 %), α-terpineol (13.3 %), α-pinene (11.1 %), caryophyllene oxide (8.8 %), limonene (8.1 %), borneol (6.0 %) and viridiflorol (5.1 %). The results of the microdilution method showed that essential oil exhibited activity against Candida albicans and Streptococcus mutans with minimal inhibitory concentration values of 125 and 250 μg/mL, respectively. Furthermore, essential oil decreased the biofilm of C. albicans and S. mutans by 20.11 ± 0.27 % and 32.10 ± 4.81 % when treated with 250 μg/mL. The best docking energy was observed with viridiflorol (-29.7 kJ/mol). This study highlights that essential oil can potentially be a natural antifungal, antibacterial, and antibiofilm agent that could be applied in the pharmaceutical and food industries.
    Matched MeSH terms: Streptococcus mutans/drug effects; Streptococcus mutans/growth & development
  14. Fulltext Antimicrobial susceptibility profiles, serotype distribution and virulence determinants among invasive, non-invasive and colonizing Streptococcus agalactiae (group B streptococcus) from Malaysian patients
    Eskandarian N, Ismail Z, Neela V, van Belkum A, Desa MN, Amin Nordin S
    Eur J Clin Microbiol Infect Dis, 2015 Mar;34(3):579-84.
    PMID: 25359580 DOI: 10.1007/s10096-014-2265-x
    A total of 103 group B streptococci (GBS) including 22 invasive, 21 non-invasive, and 60 colonizing isolates were collected in a Malaysian hospital (June 2010-October 2011). Isolates were characterized by conventional and molecular serotyping and analyzed for scpB, lmb, hylB, cylE, bac, bca and rib gene content. Antimicrobial susceptibility to penicillins, macrolides, lincosamides, quinolones and tetracyclines was determined using disk diffusion and the MICs for penicillin were determined by E-test. Molecular serotyping for all eight serotypes (Ia, Ib, II-VII) was in full accordance with conventional serotyping. Overall, taking CS and MS together, serotype VI was the most common capsular type (22.3 %) followed by VII (21.4 %), III (20.4 %), Ia (17.5 %), V (9.7 %), II (7.7 %) and IV (1 %). Susceptibility to beta-lactam antimicrobials was prevalent (100 %). Resistance rates for erythromycin, clindamycin and tetracycline were 23.3 %, 17.5 % and 71.8 %, respectively. PCR-virulence gene screening showed the presence of cylE, lmb, scpB and hylB in almost all the isolates while rib, bca, and bac genes were found in 29.1 %, 14.6 % and 9.7 % of the isolates. Certain genes were significantly associated with specific serotypes, namely, rib with serotypes Ia, II, III and VI; bca and bac with serotypes II and III. Furthermore, serotype Ia was significantly more common among patients with invasive infections (p 
    Matched MeSH terms: Streptococcus agalactiae/classification; Streptococcus agalactiae/drug effects; Streptococcus agalactiae/genetics; Streptococcus agalactiae/isolation & purification*
  15. Genotypic characterization of Malaysian human isolates of Streptococcus pneumoniae from carriage and clinical sources
    Shakrin NN, Masri SN, Taib NM, Nordin SA, Jamal F, Desa MN
    Comp Immunol Microbiol Infect Dis, 2014 Dec;37(5-6):347-54.
    PMID: 25467035 DOI: 10.1016/j.cimid.2014.10.005
    This study characterized carriage and clinical pneumococcal isolates for serotypes, penicillin susceptibility, virulence genes and restriction fragment length polymorphism (RFLP) pattern of penicillin binding protein (PBP) genes. DNA fingerprint of isolates was generated by BOX-PCR. Majority of serotypes were 23F followed by 19F, 19A and 6A. Twenty-four percent of isolates were penicillin non-susceptible (PNSP). All of the targeted virulence genes were detected in all isolates with the exception of pili; 20.6% (n=22) for PI-1 and 14.0% (n=15) for PI-2. Of the 13 isolates which carried both PI-1 and PI-2, 10 were of clinical origin. Digested pbp-DNA produced three PBP-RFLP profiles for pbp1a (A1 to A3), six profiles for pbp2b (B1 to B6) and seven for pbp2x (X1 to X7) mostly in PNSPs. Based on BOX-PCR analysis, the majority of isolates were genetically diverse with a small number of potentially related isolates carrying pili genes. No obvious genotypic association was observed pertaining to carriage and clinical origin of isolates.
    Matched MeSH terms: Streptococcus pneumoniae/classification; Streptococcus pneumoniae/drug effects; Streptococcus pneumoniae/genetics*; Streptococcus pneumoniae/pathogenicity*
  16. Fulltext Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects
    Barbour A, Philip K
    PLoS One, 2014;9(6):e100541.
    PMID: 24941127 DOI: 10.1371/journal.pone.0100541
    Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production.
    Matched MeSH terms: Streptococcus/drug effects; Streptococcus/genetics; Streptococcus/isolation & purification; Streptococcus/metabolism*
  17. Fulltext Determination of phenotypes and pneumococcal surface protein A family types of Streptococcus pneumoniae from Malaysian healthy children
    Yatim MM, Masri SN, Desa MN, Taib NM, Nordin SA, Jamal F
    J Microbiol Immunol Infect, 2013 Jun;46(3):180-6.
    PMID: 22763088 DOI: 10.1016/j.jmii.2012.04.004
    There is limited information about pneumococcal carriage among healthy children in Malaysia. Therefore, this study was conducted to determine the prevalence rate, serotype distribution, susceptibility pattern, and pneumococcal surface protein A (PspA) family types of Streptococcus pneumoniae isolates in the nasal carriage of children 5 years old or younger in three day care centers in Kuala Lumpur, Malaysia.
    Matched MeSH terms: Streptococcus pneumoniae/classification*; Streptococcus pneumoniae/genetics; Streptococcus pneumoniae/isolation & purification; Streptococcus pneumoniae/physiology
  18. An outbreak of Streptococcus agalactiae infection in cage-cultured golden pompano, Trachinotus blochii (Lacépède), in Malaysia
    Amal MN, Zamri-Saad M, Iftikhar AR, Siti-Zahrah A, Aziel S, Fahmi S
    J Fish Dis, 2012 Nov;35(11):849-52.
    PMID: 22913387 DOI: 10.1111/j.1365-2761.2012.01443.x
    Matched MeSH terms: Streptococcus agalactiae/drug effects; Streptococcus agalactiae/genetics; Streptococcus agalactiae/isolation & purification; Streptococcus agalactiae/physiology*
  19. Expression of the serum opacity factor gene and the variation in its upstream region in Streptococcus dysgalactiae isolates from fish
    Nishiki I, Minami T, Chen SC, Itami T, Yoshida T
    J Gen Appl Microbiol, 2012;58(6):457-63.
    PMID: 23337581
    Group C Streptococcus dysgalactiae (GCSD) is a pathogen of farmed fish. Almost all GCSD isolates from Asian countries, including Japan, Taiwan, Malaysia, and China, have a serum opacity factor (SOF-FD). Although the SOF-FD sequences in different GCSD isolates are identical, different opacification activities are observed. Three types of variations were observed in the upstream sequence of the sof-FD gene in GCSD isolates with different SOF-FD activities. Type 1 was characterized by insertion of an IS981-like element into the upstream region of the sof-FD gene. In Type 2, an IS981-like element was inserted into the upstream region in a direction opposite to that in Type 1. In Type 3, no IS element was inserted. Type 1 was predominant among Japanese isolates (129 of 133). Isolates from other Asian countries were generally Type 3 (13 of 16). Except for 1 strain, Type 1 strains exhibited opacification activities with optical densities (ODs)>0.6, while Type 2 and Type 3 strains have low opacification activities (ODs >0.2). Only Type 1 strains have putative -10 and -35 promoter regions upstream of the sof-FD gene, and the expression level of the sof-FD gene was higher in Type 1 strains than in Type 2 and Type 3 strains.
    Matched MeSH terms: Streptococcus/classification*; Streptococcus/genetics; Streptococcus/isolation & purification*; Streptococcus/metabolism
  20. Fulltext Molecular detection and genotypic characterisation of Streptococcus pneumoniae isolated from children in Malaysia
    Goh SL, Kee BP, Abdul Jabar K, Chua KH, Nathan AM, Bruyne J, et al.
    Pathog Glob Health, 2020 02;114(1):46-54.
    PMID: 32003298 DOI: 10.1080/20477724.2020.1719325
    Streptococcus pneumoniae (S. pneumoniae) is one of the main causative agents of pneumococcal diseases. To date, more than 90 distinct serotypes have been identified. Implementation of vaccines has caused a drastic reduction in vaccine-serotype pneumococcal diseases but increase in cases due to non-vaccine serotype has been observed in Malaysia. However, further investigation on different serotype incidence in Malaysia is needed and the rate of pneumococcal vaccination for new-born babies in Malaysia remains low. The recent emergence of drug-resistant S. pneumoniae (DRSP) has also been a global concern, especially penicillin resistance. This study determined the serotypes of S. pneumoniae strains (n = 95) isolated from nasopharyngeal specimens from children admitted to UMMC from 2013 to 2015. In accordance with previous studies, PCR result showed 40% of NT isolates were successfully typed as 3 less common serotypes, namely 9N/L, 17A, and 23B. The repetitive-element PCR (REP-PCR) result revealed genetic variations among the strains whereby five major clusters were observed at the similarity of 80% by clustering analysis based on fingerprint data. Penicillin-binding proteins (pbps) of selected isolates were studied by PCR and sequencing. Three strains with ≤19-mm diameter zone for Oxacillin Disc Diffusion (ODD) test previously were recorded to have mutation on all pbp1a, pbp2b, and pbp2x with MIC of 4 µg/ml, which were penicillin-intermediate resistance according to the CLSI breakpoints.
    Matched MeSH terms: Streptococcus pneumoniae/classification; Streptococcus pneumoniae/drug effects; Streptococcus pneumoniae/genetics*; Streptococcus pneumoniae/isolation & purification*
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