Methicillin-resistant Staphylococcus aureus (MRSA) is a priority nosocomial pathogen with plasmids playing a crucial role in its genetic adaptability, particularly in the acquisition and spread of antimicrobial resistance. In this study, the genome sequences of 79 MSRA clinical isolates from Terengganu, Malaysia, (obtained between 2016 and 2020) along with an additional 15 Malaysian MRSA genomes from GenBank were analyzed for their plasmid content. The majority (90%, 85/94) of the Malaysian MRSA isolates harbored 1-4 plasmids each. In total, 189 plasmid sequences were identified ranging in size from 2.3 kb to ca. 58 kb, spanning all seven distinctive plasmid replication initiator (replicase) types. Resistance genes (either to antimicrobials, heavy metals, and/or biocides) were found in 74% (140/189) of these plasmids. Small plasmids (<5 kb) were predominant (63.5%, 120/189) with a RepL replicase plasmid harboring the ermC gene that confers resistance to macrolides, lincosamides, and streptogramin B (MLSB) identified in 63 MRSA isolates. A low carriage of conjugative plasmids was observed (n = 2), but the majority (64.5%, 122/189) of the non-conjugative plasmids have mobilizable potential. The results obtained enabled us to gain a rare view of the plasmidomic landscape of Malaysian MRSA isolates and reinforces their importance in the evolution of this pathogen.
Piper sarmentosum is a creeping herb belongs to the family of Piperaceae. It is locally known to the Malays as 'Pokok kadok' and can be found in different regions of South-East Asia including Malaysia. Ethnopharmacologically, various parts of the plant (e.g. leave, fruit and root) are widely used in Asian countries for centuries to treat different types of diseases and ailments such as hypertension, diabetes, joint aches, muscle pain, coughs, influenza, toothaches and rheumatism. Scientific findings also demonstrated different pharmacological actions of various parts of P. sarmentosum such as adulticidal, antitermite, antioxidant, antifungal, antituberclosis, antiplasmoid, antimalarial, hypoglycemia, antiinflammatory, antinoceptive, antipyretic, antibacterial, anticancer, antituberculosis, antiangiogenesis, antimicrobial, antifeedant and cytotoxic activities. Different types of phytochemical constituents have been successfully identified and isolated from various parts of P. sarmentosum. Therefore, the information related to the botany, ethnomedicinal uses, phytochemical constituents and pharmacological activities of P. sarmentosum were reviewed here.
The indiscriminate released of heavy metals and xenobiotics into soils and aquatic bodies severely alter soil organisms and the ecosystem. The isolation of xenobiotics degrading microorganisms is cost-effective and naturally pleasant approach. Lately, the toxicological effect of molybdenum to the spermatogenesis of several organisms has been record. This present study is aimed at the isolation and characterization of a bacterium capable of converting molybdenum to the colloidal molybdenum blue. Bacteria characterization was performed in a microplate format using resting cells. Thus, the reduction process can be employed as a device for molybdenum bioremediation. The results of the study revealed an optimum reduction at pH between 6.0 and 6.3 and temperatures of between 25 and 40 oC. Similarly, it was also observed that a phosphate concentration not greater than 5.0 mM and a sodium molybdate concentration at 20 mM was required for reduction. Glucose was observed as the best carbon source to support reduction. Following the scanning of molybdenum blue, it revealed an absorption spectrum indicating the characteristics of molybdenum blue as a reduced phosphomolybdate. Molybdenum reduction is inhibited by heavy metals like silver, lead, arsenic and mercury. Furthermore, the ability of the bacterium (Pseudomonas sp. strain Dr.Y Kertih) to utilize several organic xenobiotics such as phenol, acrylamide, nicotinamide, acetamide, iodoacetamide, propionamide, acetamide, sodium dodecyl sulfate (SDS) and diesel as electron donor sources for aiding reduction or as carbon sources for growth was also examined. Finding showed that none was capable of aiding molybdenum reduction, however the bacterium was capable of growing on both diesel and phenol as carbon sources. GC analysis was used to confirmed diesel degradation.
Genotyping methods are vital epidemiological tools for discriminating different bacterial isolates within same species, which in turn provide useful data in tracing source of infection and disease management. There have been a revolutionary efforts in ways to distinguish between bacterial types and subtypes at molecular level utilizing DNA in the genomes. Notably, the growth of various DNA typing methods has provided innovative apparatuses for improved surveillance and outbreak investigation. Thus, early identification and genotyping are indispensable as resources for managing therapeutic treatment and the control of rapid expansion of clinically important bacteria. Methicillin-resistant Staphylococcus aureus (MRSA) has been in a great attention due to its contagious nature and subjected to various typing analyses. Thus, in this chapter, we aimed to review the contribution of various genotyping methods of commonly used as well as those unique to staphylococci in understanding its epidemiology, infection and dissemination pattern, and to provide an impression of specific advantages and disadvantages of each tool.
The fungus isolated from diseased Echinochloa crus-galli was identified as Exserohilum monoceras, based on the conidial morphology, germination characteristics and hilum morphology. The objectives of this study were to screen and isolate fungal pathogen of E. monoceras from infected E. crus-galli as well as to determine the pathogenicity of E. monoceras and the optimum conditions for growth and sporulation of E. monoceras . In repeated trials, the pathogenicity of this fungus to its host was confirmed by Koch’s postulate. The pathogen caused a high level of disease on E. crus -galli where symptoms appeared within 24 h of inoculation. It induced eyespot lesions typical of infection by Exserohilum spp. and induced a seve re ‘burnt’ appearance on the foliage of E. crus -galli. The leaf tissues in the vicinity of heavy infestation were completel y killed. The disease did not develop on non -inoculated plants, which was indicative of localized infection and lack of significant secondary disease cycles. The laboratory study indicated that better growth and appressoria production can be attained when the fungus is exposed to temperature in the range of 25 to 30 o C. This study also indicated that Maxigreen ® , which is an adjuvant, when mixed with sunflower in the ratio of 0:5:7 is ideal for formulating the conidia. This research has illustrated that solid media such as agar is an excellent growth media, but spore production has been influenced by the nutrient content of the media. The best medium for sporulation was half strength V8 juice agar.
Jatropha curcas is a drought-resistant tree belonging to the family Euphorbiaceae. The latex of J. curcas has been traditionally used to heal wounds and has reported anti-coagulant and coagulant properties. In this study, fractions of the methanol, aqueous, ethyl acetate and hexane extracts from the Jatropha latex were tested for antibacterial properties against nine different human pathogenic bacteria, namely three different isolates of Staphylococcus aureus (one methicillin-resistant strain MRSA ATCC 33591, and two methicillin-sensitive strains MSSA ATCC 29213 and ATCC 25174), Salmonella enterica serovar typhi, Streptococcus agalactiae, Serratia marcescens, Klebsiella pneumoniae, Enterococcus faecalis (E248), Escherichia coli (ATCC 35218), Listeria monocytogenes (IMR L10), and Morganella morgenii (IMR MM99). The zones of inhibition produced by the extracts using an agar well diffusion method against the test microorganisms were found to range from 2.7 to 29 mm. The methanol extract was found to be the most effective extract with MIC values ranging from 0.39 mg/ml for methicillin-sensitive S. aureus and 6.25 mg/ml for S. marcescens. Hexane extracts did not show any antibacterial activity. Phytochemical screening of the J. curcas latex indicated the presence of saponins and tannins which are known to have antibacterial properties.
Key words: Jatropha curcas latex, antibacterial properties and human pathogenic bacteria.
The aim of this study was to study the genotype of a hospital collection of Group B Streptococcus (GBS) from invasive and non-invasive sites. Fifty-one pre-characterised human of GBS were re-identified and further analysed by multilocus sequence typing (MLST) in relation to previously published serotypes. Fifteen sequence types (ST) were found with ST1 being the most predominant. ST1 was also associated with majority of the invasive isolates. The genotypic distribution patterns of GBS in this study were largely in agreement with previous reports from other countries indicating the tendency of certain genotypes to prevail in human infection settings.
Published genomics data regarding CA-MRSA and HA-MRSA isolates from Malaysia
are scarce. Therefore, the aim of this study was to characterise the Malaysian CA-MRSA
and HA-MRSA isolates in depth using molecular typing, as well as whole-genome
sequencing. CA-S. aureus isolates were obtained from the nasal swabs of undergraduate
students whereas HA-S. aureus isolates were archived samples obtained from hospital
laboratories. Out of 168 S. aureus nasal carriage isolates obtained, the occurrence of
MRSA was 8.3% and 15% among undergraduate students of the agriculture
biotechnology and health sciences programmes, respectively, with multidrug resistance
were observed in 15% (26/168) of the isolates. Among the 146 hospital archived samples
of S. aureus, 28% (41/146) were MRSA, out of which 63% (i.e. 26/41) were categorised
as multidrug-resistant (MDR; resistant to three or more classes of antimicrobial
compounds).
The most predominant SCCmec type among both CA- and HA-MRSA was SCCmec-III,
with the highest occurrences observed among HA-MRSA (68%; 28/41) compared to
CA-MRSA (41%; 9/22) isolates. Other SCCmec types that were found in CA-MRSA
were SCCmec-IV (32%), SCCmec-I (23%), and SCCmec-II (4%), while in HA-MRSA
were SCCmec-IV (22%), SCCmec-V (7%), and SCCmec-I (2%). spa type t037 was the
most predominantly found among CA-MRSA (50%) and HA-MRSA (61%). Higher
occurrence of the pvl gene (which encodes the pore-forming Panton-Valentine
leucocidin) at 27% (11/41) among HA-MRSA compared to CA-MRSA at 23% (5/22).
Another virulence factor, the staphylococcal surface protein gene (sasX), was more
prevalent in HA-MRSA at 61% (25/41) compared with CA-MRSA (50%; 11/22). Nine S. aureus isolates representing HA-MRSA (SAZ_1, SAZ_10, SAZ_16, SAZ_31,
and KT/Y21), hospital-associated methicillin-susceptible S. aureus (HA-MSSA,
M314250), and CA-MRSA (ZS_Z30, ZS_Z37 and ZS_Z46) were subjected to wholegenome
sequence analysis. Genomic content of all isolates were diverse with the
presence of various mobile genetic elements (MGEs) such as insertional sequence (IS),
transposons, plasmids, genomic islands (νSAα and νSAβ), phages, Staphylococcal
pathogenicity islands (SaPIs: SaPI1, SaPI2, SaPI3, and SaPI5) as well as both virulence
and resistance determinants. In-silico, MLST and spa type of nine representative isolates
revealed five sequence types (ST)-spa types combinations, i.e. ST1-t127 (M314250),
ST30-t122 (SAZ_31), ST239-t037 (SAZ_10, ZS_Z30, ZS_Z37, and ZS_Z46), ST239-
t421 (SAZ_1), and ST772-t657 (SAZ_16 and KT/Y21). Interestingly, one of the HAMRSA
isolates, SAZ_10, harboured a novel 35 kb conjugative plasmid designated
pSAZ10A that carried multiple antimicrobial resistance (AMR) determinants (aadD,
ileS, and tcaA) as well as complete conjugative transfer (tra) genes.
Genome analyses showed the presence of multidrug efflux pumps and AMR genes,
which were likely to contribute to the MDR phenotypes in these isolates. Moreover,
various virulence factors were revealed among both CA and HA-MRSA isolates, which
were likely to play essential roles in their pathogenesis. Pan-genome analysis of all
representative isolates and other 49 global reference strains revealed an open genome
with a large accessory genome allowing acquisition of exogenous DNA and facilitating
successful adaptation to the selective hospital and community environment.
Thus, this analysis provided us an insight into the characteristics and adaptability related
to both virulence and resistance of MRSA and MSSA of Malaysian isolates, which will
assist in the surveillance, prevention and control of pathogenic S. aureus particularly in
community- and hospital-associated environment.
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