Displaying publications 1 - 20 of 26 in total

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  1. Al-Wrafy FA, Alariqi R, Noman EA, Al-Gheethi AA, Mutahar M
    Microbiol Res, 2023 Mar;268:127298.
    PMID: 36610273 DOI: 10.1016/j.micres.2022.127298
    Pseudomonas aeruginosa is mostly associated with persistent infections and antibiotic resistance as a result of several factors, biofilms one of them. Microorganisms within the polymicrobial biofilm (PMB) reveal various transcriptional profiles and affect each other which might influence their pathogenicity and antibiotic tolerance and subsequent worsening of the biofilm infection. P. aeruginosa within PMB exhibits various behaviours toward other microorganisms, which may enhance or repress the virulence of these microbes. Microbial neighbours, in turn, may affect P. aeruginosa's virulence either positively or negatively. Such interactions among microorganisms lead to emerging persistent and antibiotic-resistant infections. This review highlights the relationship between P. aeruginosa and its microbial neighbours within the PMB in an attempt to better understand the mechanisms of polymicrobial interaction and the correlation between increased exacerbations of infection and the P. aeruginosa-microbe interaction. Researching in the literature that was carried out in vitro either in co-cultures or in the models to simulate the environment at the site of infection suggested that the interplay between P. aeruginosa and other microorganisms is one main reason for the worsening of the infection and which in turn requires a treatment approach different from that followed with P. aeruginosa mono-infection.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  2. Nik Zuraina NMN, Mohamad S, Hasan H, Goni MD, Suraiya S
    Pathog Glob Health, 2023 Feb;117(1):63-75.
    PMID: 35331083 DOI: 10.1080/20477724.2022.2028378
    Respiratory tract infections (RTIs), including pneumonia and pulmonary tuberculosis, are among the leading causes of death worldwide. The use of accurate diagnostic tests is crucial to initiate proper treatment and therapy to reduce the mortality rates for RTIs. A PCR assay for simultaneous detection of six respiratory bacteria: Haemophilus influenzae, Klebsiella pneumoniae, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae, was developed in our lab. The current study aimed to evaluate the performance of this assay along with the retrospective surveillance of respiratory pathogens at a teaching hospital in Kelantan, Malaysia. Leftover sputa (n = 200) from clinical laboratories were collected and undergone DNA template preparation for PCR analysis. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of the PCR assay were determined in comparison with the gold standard sputum culture. Overall, the accuracy performance of this assay was 94.67% (95% CI: 90.87% to 97.21%) with sensitivity, specificity, PPV and NPV of 100%, 91.67%, 87.1% and 100%, respectively. Based on the organisms detected from sputa, K. pneumoniae ranked as the top isolate (n = 48), followed by P. aeruginosa (n = 13) and H. influenzae (n = 10). Surveillance among the patients showed that the associations of bacterial positive with gender and means of acquisition were found significant (p values = 0.049 and 0.001, respectively). Besides the promising performance of this ready-to-use molecular-based assay for the rapid detection of selected bacteria pathogens, this study also highlighted significant spread of K. pneumoniae RTIs in the community.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  3. Liew SM, Puthucheary SD, Rajasekaram G, Chai HC, Chua KH
    Mol Biol Rep, 2021 Mar;48(3):2325-2333.
    PMID: 33728559 DOI: 10.1007/s11033-021-06262-8
    Pseudomonas aeruginosa is a ubiquitous bacterium, which is able to change its physiological characteristics in response to different habitats. Environmental strains are presumably less pathogenic than clinical strains and whether or not the clinical strains originate from the environment or through inter-host transmission remains poorly understood. To minimize the risk of infection, a better understanding of proteomic profiling of P. aeruginosa is necessary for elucidating the correlation between environmental and clinical strains. Based on antimicrobial susceptibility and patterns of virulence, we selected 12 clinical and environmental strains: (i) environmental, (ii) multidrug resistant (MDR) clinical and (iii) susceptible clinical strains. Whole-cell protein was extracted from each strain and subjected to two-dimensional differential gel electrophoresis (2-D DIGE) and liquid chromatography tandem mass spectrometry quadrupole time-of-flight (LC-MS QTOF). All 12 strains were clustered into 3 distinct groups based on their variance in protein expression. A total of 526 matched spots were detected and four differentially expressed protein spots (p < 0.05) were identified and all differential spots were downregulated in MDR strain J3. Upregulation of chitin binding and BON domain proteins was present in the environmental and some MDR strains, whereas the clinical strains exhibited distinct proteomic profiles with increased expression of serine protein kinase and arginine/ornithine transport ATP-binding proteins. Significant difference in expression was observed between susceptible clinical and MDR strains, as well as susceptible clinical and environmental strains. Transition from an environmental saprophyte to a clinical strain could alter its physiological characteristics to further increase its adaptation.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  4. Lu J, Zhang C, Leong HY, Show PL, Lu F, Lu Z
    J Biosci Bioeng, 2020 Mar;129(3):327-332.
    PMID: 31585857 DOI: 10.1016/j.jbiosc.2019.09.006
    In this study, the bacterial lipoxygenase (LOX) gene from Pseudomonas aeruginosa ATCC27853 (pse-LOX) was cloned, sequenced and heterologous expressed in Escherichia coli by auto-induction expression strategy. Production of the recombinant pse-LOX (pse-rLOX) gene up to 23,850 U/mL (264 mg pure protein/L bacterial culture fluid) was observed in the end of this process. To the best of our knowledge, this is the first attempt to manipulate LOX heterologous expression process using auto-induction expression approach, and it is the highest production of recombinant LOX compared with other reports. Subsequently, the resulted pse-rLOX was proved to efficiently degrade triphenylmethane dyes such as malachite green, brilliant green and aniline blue. Generally, an overproduction of the LOX from P. aeruginosa was observed in E. coli, and this recombinant gene is a potential candidate as biocatalyst for triphenylmethane dyes decolorization.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  5. Sun S, Tan LT, Fang YL, Jin ZJ, Zhou L, Goh BH, et al.
    Mol Plant Microbe Interact, 2020 Mar;33(3):488-498.
    PMID: 31710580 DOI: 10.1094/MPMI-09-19-0264-R
    Phenazine-1-carboxylic acid (PCA) is the primary active component in the newly registered, commercial biopesticide Shenqinmycin and is produced during fermentation by the engineered rhizobacterium strain Pseudomonas PA1201. Both phz1 and phz2 gene clusters contribute to PCA biosynthesis. In this study, we evaluated the role of OxyR in the regulation of PCA biosynthesis in PA1201. We first showed a functional link between oxyR expression and PCA biosynthesis. Deletion of oxyR and overexpression of oxyR both increase PCA biosynthesis. The molecular mechanisms underlying OxyR regulation of PCA production were investigated using several approaches. OxyR acts divergently in phz1 and phz2. Overexpression of oxyR activated the expression of phz1 and phz1-dependent PCA production. However, overexpression of oxyR had little effect on phz2-dependent PCA biosynthesis, while deletion of oxyR promoted phz2-dependent PCA production and exerted a negative effect on phz2 expression. Further, OxyR directly bound to the phz2 promoter region. In addition, the regulation of PCA biosynthesis by OxyR was associated with quorum sensing (QS) systems. Overexpression of OxyR positively regulated pqs QS system. Finally, transcriptomic analysis and subsequent genetic analysis revealed the small RNA phrS plays a key role in OxyR-dependent PCA accumulation. Specifically, OxyR directly binds to the phrS promoter region to positively regulate phrS expression wherein PhrS regulates the PCA positive regulator MvfR in order to control PCA biosynthesis.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  6. Madaha EL, Mienie C, Gonsu HK, Bughe RN, Fonkoua MC, Mbacham WF, et al.
    PLoS One, 2020;15(9):e0238390.
    PMID: 32886694 DOI: 10.1371/journal.pone.0238390
    Pseudomonas aeruginosa has been implicated in a wide range of post-operation wound and lung infections. A wide range of acquired resistance and virulence markers indicate surviving strategy of P. aeruginosa. Complete-genome analysis has been identified as efficient approach towards understanding the pathogenicity of this organism. This study was designed to sequence the entire genome of P. aeruginosa UY1PSABAL and UY1PSABAL2; determine drug-resistance profiles and virulence factors of the isolates; assess factors that contribute toward stability of the genomes; and thereafter determine evolutionary relationships between the strains and other isolates from similar sources. The genomes of the MDR P. aeruginosa UY1PSABAL and UY1PSABAL2 were sequenced on the Illumina Miseq platform. The raw sequenced reads were assessed for quality using FastQC v.0.11.5 and filtered for low quality reads and adapter regions using Trimmomatic v.0.36. The de novo genome assembly was made with SPAdes v.3.13 and annotated using Prokka v.2.1.1 annotation pipeline; Rapid Annotation using Subsytems Technology (RAST) server v.2.0; and PATRIC annotation tool v.3.6.2. Antimicrobial resistance genes and virulence determinants were searched through the functional annotation data generated from Prokka, RAST and PATRIC annotation pipelines; In addition to ResFinder and Comprehensive Antibiotic Resistance Database (CARD) which were employed to determine resistance genes. The PHAge Search Tool Enhanced Release (PHASTER) web server was used for the rapid identification and annotation of prophage sequences within bacterial genome. Predictive secondary metabolites were identified with AntiSMASH v.5.0. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) and cas genes regions were also investigated with the CRISPRone and CRISPRFinder server. The genome sizes of 7.0 and 6.4 Mb were determined for UY1PSABAL and UY1PSABAL2 strains with G+C contents of 66.1% and 66.48% respectively. β-lactamines resistance genes blaPAO, aminoglycoside phosphorylating enzymes genes aph(3')-IIb, fosfomycine resistance gene fosA, vancomycin vanW and tetracycline tetA were among identified resistance genes harboured in both isolates. UY1PSABAL bore additional aph(6)-Id, aph(3'')-Ib, ciprofloxacin-modifying enzyme crpP and ribosomal methylation enzyme rmtB. Both isolates were found harbouring virulence markers such as flagella and type IV pili; and also present various type III secretion systems such as exoA, exoS, exoU, exoT. Secondary metabolites such as pyochelin and pyoverdine with iron uptake activity were found within the genomes as well as quorum-sensing systems, and various fragments for prophages and insertion sequences. Only the UY1PSABAL2 contains CRISPR-Cas system. The phylogeny revealed a very close evolutionary relationship between UY1PSABAL and the similar strain isolated from Malaysia; the same trend was observed between UY1PSABAL2 and the strain from Chinese origin. Complete analyses of the entire genomes provide a wide range of information towards understanding pathogenicity of the pathogens in question.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  7. Lee WT, Tan BK, Eng SA, Yuen GC, Chan KL, Sim YK, et al.
    Food Funct, 2019 Sep 01;10(9):5759-5767.
    PMID: 31453615 DOI: 10.1039/c9fo01357a
    A strategy to circumvent the problem of multidrug resistant pathogens is the discovery of anti-infectives targeting bacterial virulence or host immunity. Black sea cucumber (Holothuria atra) is a tropical sea cucumber species traditionally consumed as a remedy for many ailments. There is a paucity of knowledge on the anti-infective capacity of H. atra and the underlying mechanisms involved. The objective of this study is to utilize the Caenorhabditis elegans-P. aeruginosa infection model to elucidate the anti-infective properties of H. atra. A bioactive H. atra extract and subsequently its fraction were shown to have the capability of promoting the survival of C. elegans during a customarily lethal P. aeruginosa infection. The same entities also attenuate the production of elastase, protease, pyocyanin and biofilm in P. aeruginosa. The treatment of infected transgenic lys-7::GFP worms with this H. atra fraction restores the repressed expression of the defense enzyme lys-7, indicating an improved host immunity. QTOF-LCMS analysis revealed the presence of aspidospermatidine, an indole alkaloid, and inosine in this fraction. Collectively, our findings show that H. atra possesses anti-infective properties against P. aeruginosa infection, by inhibiting pathogen virulence and, eventually, reinstating host lys-7 expression.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  8. Yong YY, Dykes G, Lee SM, Choo WS
    J Appl Microbiol, 2019 Jan;126(1):68-78.
    PMID: 30153380 DOI: 10.1111/jam.14091
    AIMS: To investigate the biofilm inhibitory activity of betacyanins from red pitahaya (Hylocereus polyrhizus) and red spinach (Amaranthus dubius) against Staphylococcus aureus and Pseudomonas aeruginosa biofilms.

    METHODS AND RESULTS: The pulp of red pitahaya and the leaves of red spinach were extracted using methanol followed by subfractionation to obtain betacyanin fraction. The anti-biofilm activity was examined using broth microdilution assay on polystyrene surfaces and expressed as minimum biofilm inhibitory concentration (MBIC). The betacyanin fraction from red spinach showed better anti-biofilm activity (MBIC: 0·313-1·25 mg ml-1 ) against five Staph. aureus strains while the betacyanin fraction from red pitahaya showed better anti-biofilm activity (MBIC: 0·313-0·625 mg ml-1 ) against four P. aeruginosa strains. Both betacyanin fraction significantly reduced hydrophobicity of Staph. aureus and P. aeruginosa strains. Numbers of Staph. aureus and P. aeruginosa attached to polystyrene were also reduced without affecting their cell viability.

    CONCLUSION: Betacyanins can act as anti-biofilm agents against the initial step of biofilm formation, particularly on a hydrophobic surface like polystyrene.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This study is the first to investigate the use of betacyanin as a biofilm inhibitory agent. Betacyanin could potentially be used to reduce the risk of biofilm-associated infections.

    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  9. Phoon HYP, Hussin H, Hussain BM, Thong KL
    Microb Drug Resist, 2018 Oct;24(8):1108-1116.
    PMID: 29437541 DOI: 10.1089/mdr.2017.0258
    Pseudomonas aeruginosa infections account for high morbidity and mortality rates worldwide. Increasing resistance toward β-lactams, especially carbapenems, poses a serious therapeutic challenge. However, the multilocus sequence typing (MLST) of extended-spectrum beta lactamase (ESBL)- and carbapenemase-producing clinical P. aeruginosa has not been reported in Malaysia. This study aimed to determine the antibiotic susceptibility profiles, resistance genes, pulsotypes, and sequence types (STs) of clinical P. aeruginosa from a Malaysian tertiary hospital. These characteristics were analyzed by disk diffusion, minimum inhibitory concentration, polymerase chain reaction, pulsed-field gel electrophoresis (PFGE), and MLST for 199 nonreplicate clinical strains. The susceptibility of the strains toward the carbapenems and piperacillin-tazobactam was the lowest (≤90%), while ≥90% of the strains remained susceptible to all other classes of antimicrobial agents tested. The multidrug-resistant strains displayed high level resistance to cephalosporins (48 to ≥256 mg/L) and carbapenems (4-32 mg/L). Eleven strains harbored class 1 integrons containing blaGES-13, blaVIM-2, blaVIM-6, blaOXA-10, aacA(6')-Ib, aacA(6')-II, aadA6, and gcuD gene cassettes. Extra-integron genes, blaGES-20, blaIMP-4, blaVIM-2, and blaVIM-11, were also found. Overall, the maximum likelihood tree showed concordance in the clustering of strains having the same STs and PFGE clusters. ST708 was the predominant antibiotic-susceptible clone detected from the neonatal intensive care unit. The STs 235, 809, and 1076 clonal clusters consisted of multidrug resistant strains. ST235 is a recognized international high-risk clone. This is the first report of blaGES-13 and blaGES-20 ESBL-encoding gene variants and novel STs (STs 2329, 2335, 2337, 2338, 2340, and 2341) of P. aeruginosa in Malaysia.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  10. Romero M, Silistre H, Lovelock L, Wright VJ, Chan KG, Hong KW, et al.
    Nucleic Acids Res, 2018 07 27;46(13):6823-6840.
    PMID: 29718466 DOI: 10.1093/nar/gky324
    Pseudomonads typically carry multiple non-identical alleles of the post-transcriptional regulator rsmA. In Pseudomonas aeruginosa, RsmN is notable in that its structural rearrangement confers distinct and overlapping functions with RsmA. However, little is known about the specificities of RsmN for its target RNAs and overall impact on the biology of this pathogen. We purified and mapped 503 transcripts directly bound by RsmN in P. aeruginosa. About 200 of the mRNAs identified encode proteins of demonstrated function including some determining acute and chronic virulence traits. For example, RsmN reduces biofilm development both directly and indirectly via multiple pathways, involving control of Pel exopolysaccharide biosynthesis and c-di-GMP levels. The RsmN targets identified are also shared with RsmA, although deletion of rsmN generally results in less pronounced phenotypes than those observed for ΔrsmA or ΔrsmArsmNind mutants, probably as a consequence of different binding affinities. Targets newly identified for the Rsm system include the small non-coding RNA CrcZ involved in carbon catabolite repression, for which differential binding of RsmN and RsmA to specific CrcZ regions is demonstrated. The results presented here provide new insights into the intricacy of riboregulatory networks involving multiple but distinct RsmA homologues.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  11. Liew SM, Rajasekaram G, Puthucheary SD, Chua KH
    J Glob Antimicrob Resist, 2018 06;13:271-273.
    PMID: 29432937 DOI: 10.1016/j.jgar.2018.01.026
    OBJECTIVES: The increasing incidence of carbapenem-resistant Pseudomonas aeruginosa along with the discovery of novel metallo-β-lactamases (MBLs) is of concern. In this study, the isolation of MBL-producing P. aeruginosa clinical strains in Malaysia was investigated.

    METHODS: A total of 53 P. aeruginosa clinical strains were isolated from different patients in Sultanah Aminah Hospital (Johor Bahru, Malaysia) in 2015. Antimicrobial susceptibility testing was performed, and minimum inhibitory concentrations (MICs) of imipenem and meropenem were determined by Etest. Carbapenem-resistant strains were screened for MBL production by the imipenem-ethylene diamine tetra-acetic acid (IMP-EDTA) double-disk synergy test, MBL imipenem/imipenem-inhibitor (IP/IPI) Etest and PCR. Multilocus sequence typing (MLST) analysis was performed for genotyping of the isolates.

    RESULTS: Among the 53 clinical strains, 3 (5.7%) were identified as MBL-producers. Multidrug resistance was observed in all three strains, and two were resistant to all of the antimicrobials tested. Sequencing analysis confirmed that the three strains harboured carbapenemase genes (blaIMP-1, blaVIM-2 and blaNDM-1 in one isolate each). These multidrug-resistant strains were identified as sequence type 235 (ST235) and ST308.

    CONCLUSIONS: The blaIMP-1 and blaNDM-1 genes have not previously been reported in Malaysian P. aeruginosa isolates. The emergence of imipenemase 1 (IMP-1)- and New Delhi metallo-β-lactamase 1 (NDM-1)-producing P. aeruginosa in Malaysia maybe travel-associated.

    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  12. Ramanathan B, Jindal HM, Le CF, Gudimella R, Anwar A, Razali R, et al.
    PLoS One, 2017;12(8):e0182524.
    PMID: 28797043 DOI: 10.1371/journal.pone.0182524
    Rapid progress in next generation sequencing and allied computational tools have aided in identification of single nucleotide variants in genomes of several organisms. In the present study, we have investigated single nucleotide polymorphism (SNP) in ten multi-antibiotic resistant Pseudomonas aeruginosa clinical isolates. All the draft genomes were submitted to Rapid Annotations using Subsystems Technology (RAST) web server and the predicted protein sequences were used for comparison. Non-synonymous single nucleotide polymorphism (nsSNP) found in the clinical isolates compared to the reference genome (PAO1), and the comparison of nsSNPs between antibiotic resistant and susceptible clinical isolates revealed insights into the genome variation. These nsSNPs identified in the multi-drug resistant clinical isolates were found to be altering a single amino acid in several antibiotic resistant genes. We found mutations in genes encoding efflux pump systems, cell wall, DNA replication and genes involved in repair mechanism. In addition, nucleotide deletions in the genome and mutations leading to generation of stop codons were also observed in the antibiotic resistant clinical isolates. Next generation sequencing is a powerful tool to compare the whole genomes and analyse the single base pair variations found within the antibiotic resistant genes. We identified specific mutations within antibiotic resistant genes compared to the susceptible strain of the same bacterial species and these findings may provide insights to understand the role of single nucleotide variants in antibiotic resistance.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  13. Popat R, Pollitt EJ, Harrison F, Naghra H, Hong KW, Chan KG, et al.
    Evolution, 2015 Sep;69(9):2371-83.
    PMID: 26282874 DOI: 10.1111/evo.12751
    Animals use signals to coordinate a wide range of behaviors, from feeding offspring to predator avoidance. This poses an evolutionary problem, because individuals could potentially signal dishonestly to coerce others into behaving in ways that benefit the signaler. Theory suggests that honest signaling is favored when individuals share a common interest and signals carry reliable information. Here, we exploit the opportunities offered by bacterial signaling to test these predictions with an experimental evolution approach. We show that: (1) reduced relatedness leads to the relative breakdown of signaling, (2) signaling breaks down by the invasion of mutants that show both reduced signaling and reduced response to signal, (3) the genetic route to signaling breakdown is variable, and (4) the addition of artificial signal, to interfere with signal information, also leads to reduced signaling. Our results provide clear support for signaling theory, but we did not find evidence for previously predicted coercion at intermediate relatedness, suggesting that mechanistic details can alter the qualitative nature of specific predictions. Furthermore, populations evolved under low relatedness caused less mortality to insect hosts, showing how signal evolution in bacterial pathogens can drive the evolution of virulence in the opposite direction to that often predicted by theory.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  14. Kim MJ, Bae IK, Jeong SH, Kim SH, Song JH, Choi JY, et al.
    J Antimicrob Chemother, 2013 Dec;68(12):2820-4.
    PMID: 23843299 DOI: 10.1093/jac/dkt269
    To investigate the epidemiological traits of metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa (MPPA) clinical isolates collected by the Asian Network for Surveillance of Resistant Pathogens (ANSORP).
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  15. Kor SB, Choo QC, Chew CH
    J Med Microbiol, 2013 Mar;62(Pt 3):412-420.
    PMID: 23180481 DOI: 10.1099/jmm.0.053645-0
    This study investigated 147 multidrug-resistant Enterobacteriaceae and Pseudomonas aeruginosa isolates from hospitalized patients in Malaysia. Class 1 integrons were the most dominant class identified (45.6%). Three isolates were shown to contain class 2 integrons (2.0%), whilst one isolate harboured both class 1 and 2 integrons. No class 3 integrons were detected in this study. In addition, the sul1 gene was amplified in 35% of isolates and was significantly associated with the presence of integrase genes in an integron structure. RFLP and DNA sequencing analyses revealed the presence of 19 different cassette arrays among the detected integrons. The most common gene cassettes were those encoding resistance towards aminoglycosides (aad) and trimethoprim (dfr). As far as is known, this study is the first to identify integron-carrying cassette arrays such as aadA2-linF, aacC3-cmlA5 and aacA4-catB8-aadA1 in the Malaysian population. Patients' age was demonstrated as a significant risk factor for the acquisition of integrons (P=0.028). Epidemiological typing using PFGE also demonstrated a clonal relationship among isolates carrying identical gene cassettes in Klebsiella pneumoniae and P. aeruginosa but not in Escherichia coli isolates.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  16. Wong CS, Yin WF, Choo YM, Sam CK, Koh CL, Chan KG
    World J Microbiol Biotechnol, 2012 Feb;28(2):453-61.
    PMID: 22806840 DOI: 10.1007/s11274-011-0836-x
    A chemically defined medium called KGm medium was used to isolate from a sample of sea water a bacterial strain, MW3A, capable of using N-3-oxohexanoyl-L: -homoserine lactone as the sole carbon source. MW3A was clustered closely to Pseudomonas aeruginosa by 16S ribosomal DNA sequence analysis. It degraded both N-acylhomoserine lactones (AHLs) with a 3-oxo group substitution and, less preferably, AHLs with unsubstituted groups at C3 position in the acyl side chain, as determined by Rapid Resolution Liquid Chromatography. Its quiP and pvdQ homologue gene sequences showed high similarities to those of known acylases. Spent supernatant of MW3A harvested at 8-h post inoculation was shown to contain long-chain AHLs when assayed with the biosensor Escherichia coli [pSB1075], and specifically N-dodecanoyl-L: -homoserine lactone and N-3-oxotetradecanoyl-L: -homoserine lactone by high resolution mass spectrometry. Hence, we report here a novel marine P. aeruginosa strain MW3A possessing both quorum-quenching and quorum-sensing properties.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
  17. Wong CS, Yin WF, Sam CK, Koh CL, Chan KG
    New Microbiol., 2012 Jan;35(1):43-51.
    PMID: 22378552
    Most Proteobacteria produce N-acylhomoserine lactones for bacterial cell-to-cell communication, a process called quorum sensing. Interference of quorum sensing, commonly known as quorum quenching, represents an important way to control quorum sensing. This work reports the isolation of quorum quenching bacterium strain 2WS8 from Malaysia tropical wetland water (2°11'8"N, 102°15'2"E, in 2007) by using a modified version of a previously reported KG medium. Strain 2WS8 was isolated based on its ability to utilize N-(3-oxohexanoyl)-L-homoserine lactone (3-oxo-C6-HSL) as the sole source of energy. This bacterium clustered closely to Pseudomonas aeruginosa PAO1. Strain 2SW8 possesses both quiP and pvdQ homologue acylase genes. Rapid Resolution Liquid Chromatography analysis confirmed that strain 2SW8 preferentially degraded N-acylhomoserine lactones with 3-oxo group substitution but not those with unsubstituted groups at C3 position in the acyl side chain. Strain 2SW8 also showed 2-heptyl-3-hydroxy-4-quinolone production.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  18. Khosravi Y, Tay ST, Vadivelu J
    J Med Microbiol, 2011 Jul;60(Pt 7):988-994.
    PMID: 21436370 DOI: 10.1099/jmm.0.029868-0
    In this study, 90 non-replicate imipenem-resistant Pseudomonas aeruginosa (IRPA) Malaysian isolates collected between October 2005 and March 2008 were subjected to a screening test for detection of the integron and the gene cassette. Class 1 integrons were detected in 54 IRPA clinical isolates, whilst three isolates contained class 2 integrons. Analysis of the gene cassettes associated with the class 1 integrons showed the detection of accC1 in isolates carrying bla(IMP-7) and aacA7 in isolates carrying bla(VIM-2). aadA6 was detected in two isolates carrying bla(IMP-4). Using random amplification of polymorphic DNA analysis, 14 PCR fingerprint patterns were generated from the 32 isolates carrying metallo-β-lactamase (MBL) genes (35.5 %), whilst 20 patterns were generated from the 58 non-MBL gene isolates (64.4 %). Based on the differences in the fingerprinting patterns, two clusters (A and B) were identified among the MBL-producing isolates. Cluster A comprised 18 isolates (56 %) carrying the bla(VIM) gene, whereas cluster B comprised 14 (44 %) isolates carrying the bla(IMP) gene. The non-MBL isolates were divided into clusters C and D. Cluster C comprised 22 non-MBL isolates harbouring class 1 integrons, whilst cluster D consisted of three isolates carrying class 2 integrons. These findings suggest that the class 1 integron is widespread among P. aeruginosa isolated in Malaysia and that characterization of cassette arrays of integrons will be a useful epidemiological tool to study the evolution of multidrug resistance and the dissemination of antibiotic resistance genes.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics*
  19. Wong CF, Salleh AB, Basri M, Abd Rahman RN
    Biotechnol Appl Biochem, 2010 Sep;57(1):1-7.
    PMID: 20726840 DOI: 10.1042/BA20100224
    The structural gene of elastase strain K (elastase from Pseudomonas aeruginosa strain K), namely HindIII1500PstI, was successfully sequenced to contain 1497 bp. The amino acid sequence, deduced from the nucleotide sequence, revealed that the mature elastase consists of 301 amino acids, with a molecular mass of 33.1 kDa, and contains a conserved motif HEXXH, zinc ligands and residues involved in the catalysis of elastase strain K. The structural gene was successfully cloned to a shuttle vector, pUCP19, and transformed into Escherichia coli strains TOP10, KRX, JM109 and Tuner™ pLacI as well as P. aeruginosa strains PA01 (A.T.C.C. 47085) and S5, with detection of significant protein expression. Overexpression was detected from transformants KRX/pUCP19/HindIII1500PstI of E. coli and PA01/pUCP19/HindIII1500PstI of P. aeruginosa, with increases in elastolytic activity to 13.83- and 5.04-fold respectively relative to their controls. In addition, recombinant elastase strain K showed considerable stability towards numerous organic solvents such as methanol, ethanol, acetone, toluene, undecan-1-ol and n-dodecane, which typically pose a detrimental effect on enzymes; our finding provides further information to support the potential application of the enzyme in synthetic industries, particularly peptide synthesis.
    Matched MeSH terms: Pseudomonas aeruginosa/genetics
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