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Pseudomonas aeruginosa behaviour in polymicrobial communities: The competitive and cooperative interactions conducting to the exacerbation of infections

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
IMP-4-producing Pseudomonas aeruginosa in a French patient repatriated from Malaysia: impact of early detection and control measures

Bert F, Vanjak D, Leflon-Guibout V, Mrejen S, Delpierre S, Redondo A, et al.

Clin Infect Dis, 2007 Mar 1;44(5):764-5.
PMID: 17278079
Matched MeSH terms: Pseudomonas aeruginosa/genetics
First characterization of bla(VIM-11) cassette-containing integron in metallo-beta-lactamase producing Pseudomonas aeruginosa in Malaysia

Khosravi Y, Tay ST, Vadivelu J

Eur Rev Med Pharmacol Sci, 2010 Nov;14(11):999-1000.
PMID: 21284350
Matched MeSH terms: Pseudomonas aeruginosa/genetics*
Analysis of integrons and associated gene cassettes of metallo-β-lactamase-positive Pseudomonas aeruginosa in Malaysia

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*
Fulltext Dissemination of metallo-β-lactamase-producing Pseudomonas aeruginosa of sequence type 235 in Asian countries

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
New integron gene arrays from multiresistant clinical isolates of members of the Enterobacteriaceae and Pseudomonas aeruginosa from hospitals in Malaysia

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
Black sea cucumber (Holothuria atra Jaeger, 1833) rescues Pseudomonas aeruginosa-infected Caenorhabditis elegans via reduction of pathogen virulence factors and enhancement of host immunity

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
Proteomic profiling of clinical and environmental strains of Pseudomonas aeruginosa

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
Detection of VIM-2-, IMP-1- and NDM-1-producing multidrug-resistant Pseudomonas aeruginosa in Malaysia

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*
Genetic fingerprinting and antimicrobial susceptibility profiles of Pseudomonas aeruginosa hospital isolates in Malaysia

Lim KT, Yasin RM, Yeo CC, Puthucheary SD, Balan G, Maning N, et al.

J Microbiol Immunol Infect, 2009 Jun;42(3):197-209.
PMID: 19812853

Pseudomonas aeruginosa is the third most common pathogen causing nosocomial infections. The objective of this study was to investigate the antimicrobial resistance profiles and genetic diversity of hospital isolates of P. aeruginosa and to investigate the presence of several resistance genes and integrons.

Matched MeSH terms: Pseudomonas aeruginosa/genetics*
Overproduction of lipoxygenase from Pseudomonas aeruginosa in Escherichia coli by auto-induction expression and its application in triphenylmethane dyes degradation

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
Fulltext Whole-genome sequence of multi-drug resistant Pseudomonas aeruginosa strains UY1PSABAL and UY1PSABAL2 isolated from human broncho-alveolar lavage, Yaoundé, Cameroon

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*
Fulltext Diagnostic performance of an in-house multiplex PCR assay and the retrospective surveillance of bacterial respiratory pathogens at a teaching hospital, Kelantan, Malaysia

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
The patterns and transmissibility of antibiotic resistance among clinical strains of Pseudomonas aeruginosa

Palillo ES, Salleh MA

Microbiol. Immunol., 1992;36(11):1195-200.
PMID: 1491621

Four hundred and ninety-eight predominantly pyocin-type 10 clinical strains of Pseudomonas aeruginosa were analyzed for resistance to carbenicillin, cefoperazone, cefotaxime, ceftazidime, gentamicin, amikacin and netilmicin. Based on NCCLS-recommended MIC breakpoints, 245 strains were found to be resistant, of which 41.6% were resistant to carbenicillin, 38% to gentamicin, 37.8% to netilmicin, 26.3% to cefoperazone, 17.9% to cefotaxime, 0.6% to amikacin and none to ceftazidime. Quadruple resistance to carbenicillin, cefoperazone, gentamicin and netilmicin was the most frequent pattern observed. Resistance to older antibiotics (kanamycin, streptomycin and tetracycline) and to mercuric chloride were also common. Conjugation experiments suggested that self-transmissible and non-transmissible plasmids occurred in at least 66 strains.

Matched MeSH terms: Pseudomonas aeruginosa/genetics
Molecular Characterization of Extended-Spectrum Beta Lactamase- and Carbapenemase-Producing Pseudomonas aeruginosa Strains from a Malaysian Tertiary Hospital

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*
Fulltext Conflict of interest and signal interference lead to the breakdown of honest signaling

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
Molecular investigation of a gene encoding organic solvent-tolerant alkaline protease from Pseudomonas aeruginosa strain K

Rahman RN, Geok LP, Wong CF, Basri M, Salleh AB

J Basic Microbiol, 2010 Apr;50(2):143-9.
PMID: 20082370 DOI: 10.1002/jobm.200900133

A gene encoding an organic solvent-stable protease was amplified from Pseudomonas aeruginosa strain K by polymerase chain reaction using consensus primers based on multiple sequence alignment of alkaline and metalloprotease genes from Pseudomonas species. The gene, which consisted of 1440 bp nucleotides and deduced 479 amino acid residues, was successfully expressed in pGEX-4T-1 expression system in the presence of 1.0 mM IPTG, after an incubation of 6 h at 37 degrees C. Under these conditions, the recombinant strain K protease was, subsequently, released into the periplasm of E. coli BL21 (DE3) with an optimum proteolytic activity detected at 1.0112 U/ml. To date, this is the first reported expression of alkaline protease (aprA) with such remarkable property in Escherichia coli.

Matched MeSH terms: Pseudomonas aeruginosa/genetics*
Fulltext Next generation sequencing reveals the antibiotic resistant variants in the genome of Pseudomonas aeruginosa

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*
Fulltext Genome-wide mapping of the RNA targets of the Pseudomonas aeruginosa riboregulatory protein RsmN

Romero M, Silistre H, Lovelock L, Wright VJ, Chan KG, Hong KW, et al.

Nucleic Acids Res, 2018 Jul 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*
Assessment of polymerase chain reaction in the detection of pseudomonas aeruginosa in contact lens-induced severe infectious keratitis

Subrayan V, Peyman M, Lek Yap S, Mohamed Ali NA, Devi S

Eye Contact Lens, 2010 Jul;36(4):201-3.
PMID: 20531205 DOI: 10.1097/ICL.0b013e3181e3efa3

PURPOSE: The aim of this study is to evaluate the role of real-time polymerase chain reaction (PCR) and conventional bacterial culture methods in the detection of Pseudomonas aeruginosa in contact lens-induced severe, partially treated corneal ulcers referred to a tertiary center.
METHODS: The study duration was 6 months. All patients with contact lens-related corneal ulcer, requiring admission during the study period were recruited. Samples from corneal scrapings were simultaneously sent at the time of admission for PCR and culture testing. An in-house real-time PCR was developed to detect the P. aeruginosa lasA gene. The results of PCR and culture were compared using McNemar's chi2 test.
RESULTS: Ten patients were recruited. The mean age was 33 years (20-45 years). All the patients had contact lens-related keratitis (>4 mm) of which eight (80%) were found positive for P. aeruginosa by PCR or culture. There was no significant difference between PCR and culture in detecting P. aeruginosa (P<0.05).
CONCLUSIONS: PCR is, at least, as good as conventional cultures in detecting P. aeruginosa. It is a rapid assay as compared with culture, and early detection enables prompt treatment thus reducing the destructive effect of the organism on the cornea.

Matched MeSH terms: Pseudomonas aeruginosa/genetics*

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