Displaying publications 161 - 180 of 267 in total

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  1. Pilus islets and the clonal spread of piliated Streptococcus pneumoniae: A review
    Dzaraly ND, Muthanna A, Mohd Desa MN, Taib NM, Masri SN, Rahman NIA, et al.
    Int J Med Microbiol, 2020 Oct;310(7):151449.
    PMID: 33092697 DOI: 10.1016/j.ijmm.2020.151449
    Pneumococci are a common cause of severe infections, such as otitis media, pneumonia, meningitis and bacteremia. Pili are detected in a small proportion of pneumococcal population, but these structures have recently been associated with bacterial virulence in humans. Therefore, the epidemiological relationships between pneumococcal pili, serotype and antimicrobial resistance are of interest. This study aims to discuss the virulence contribution of the Streptococcus pneumoniae pili and the epidemiological relationships among the pilus genes, antimicrobial resistance trends, regional serotypes and genotypic variations. Previous reports have characterized the pneumococcal pilus islet as a clonal feature in the pneumococcal serotypes that are covered by the pneumococcal conjugate vaccine (PCV), including serotypes 19A, 19F, 23F and 7F. Many of the pneumococcal molecular epidemiology network (PMEN) clones are piliated isolates that are also strongly associated with a high frequency of multidrug resistance. Most of these piliated pneumococcal isolates belong to a few clonal complexes (CC), such as CC320, CC199, CC271, CC191 and CC156. Additional molecular epidemiology and genomic studies, particularly whole genome sequence analysis (WGS), are needed to develop an in-depth understanding of the piliated pneumococcal isolates.
    Matched MeSH terms: Drug Resistance, Multiple
  2. Fulltext Antibiogram Profiles and Risk Factors for Multidrug Resistance of Salmonella enterica Recovered from Village Chickens (Gallus gallus domesticus Linnaeus) and Other Environmental Sources in the Central and Southern Peninsular Malaysia
    Mohammed Jajere S, Hassan L, Zakaria Z, Abu J, Abdul Aziz S
    Antibiotics (Basel), 2020 Oct 15;9(10).
    PMID: 33076451 DOI: 10.3390/antibiotics9100701
    The emergence of multidrug resistance (MDR), including colistin resistance, among Enterobacteriaceae recovered from food animals poses a serious public health threat because of the potential transmission of these resistant variants to humans along the food chain. Village chickens or Ayam Kampung are free-range birds and are preferred by a growing number of consumers who consider these chickens to be organic and more wholesome. The current study investigates the antibiogram profiles of Salmonella isolates recovered from village chicken flocks in South-central Peninsular Malaysia. A total of 34 isolates belonging to eight serotypes isolated from village chickens were screened for resistance towards antimicrobials including colistin according to the WHO and OIE recommendations of critical antibiotics. S. Weltevreden accounted for 20.6% of total isolates, followed by serovars Typhimurium and Agona (17.6%). The majority of isolates (73.5%) demonstrated resistance to one or more antimicrobials. Eight isolates (23.5%) were resistant to ≥3 antimicrobial classes. Colistin resistance (minimum inhibitory concentrations: 4-16 mg/L) was detected among five isolates (14.7%), including S. Weltevreden, S. Albany, S. Typhimurium, and Salmonella spp. Univariable analysis of risk factors likely to influence the occurrence of MDR Salmonella revealed that the flock size, poultry production system, and use of antibiotics in the farm were not significantly (p > 0.05) associated with MDR Salmonella. The current study highlights that MDR Salmonella occur at a lower level in village chickens compared to that found in live commercial chickens. However, MDR remains a problem even among free-range chickens with minimal exposure to antibiotics.
    Matched MeSH terms: Drug Resistance, Multiple
  3. The Antibacterial Agent Identified from Acidocella spp. in the Fluid of Nepenthes gracilis Against Multidrug-Resistant Klebsiella pneumoniae: A Functional Metagenomic Approach
    Chan EWL, Chin MY, Low YH, Tan HY, Ooi YS, Chong CW
    Microb Drug Resist, 2021 Aug;27(8):1018-1028.
    PMID: 33325795 DOI: 10.1089/mdr.2020.0311
    Aims: The fluid of Nepenthes gracilis harbors diverse bacterial taxa that could serve as a gene pool for the discovery of the new genre of antimicrobial agents against multidrug-resistant Klebsiella pneumoniae. The aim of this study was to explore the presence of antibacterial genes in the fluids of N. gracilis growing in the wild. Methods: Using functional metagenomic approach, fosmid clones were isolated and screened for antibacterial activity against three strains of K. pneumoniae. A clone that exhibited the most potent antibacterial activity was sent for sequencing to identify the genes responsible for the observed activity. The secondary metabolites secreted by the selected clone was sequentially extracted using hexane, chloroform, and ethyl acetate. The chemical profiles of a clone (C6) hexane extract were determined by gas chromatography/mass spectrometry (GC-MS). Results: Fosmid clone C6 from the fluid of pitcher plant that exhibited antibacterial activity against three strains of K. pneumoniae was isolated using functional metagenome approach. A majority of the open reading frames detected from C6 were affiliated with the largely understudied Acidocella genus. Among them, the gene that encodes for coproporphyrinogen III oxidase in the heme biosynthesis pathway could be involved in the observed antibacterial activity. Based on the GC-MS analysis, the identities of the putative bioactive compounds were 2,5-di-tert-butylphenol and 1-ethyl-2-methyl cyclododecane. Conclusions: The gene that encodes for coproporphyrinogen III oxidase in the heme biosynthesis pathway as well as the secondary metabolites, namely 2,5-di-tert-butylphenol and 1-ethyl-2-methyl cyclododecane could be the potential antibacterial molecules responsible for the antibacterial activity of C6.
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  4. Gastrointestinal infections in children in the Southeast Asia region: emerging issues
    Lee WS
    J Pediatr Gastroenterol Nutr, 2000 Mar;30(3):241-5.
    PMID: 10749405
    Matched MeSH terms: Drug Resistance, Multiple
  5. The Multidrug-Resistant Gram-negative Superbugs Threat Require Intelligent Use of the Last Weapon
    Deris ZZ
    Malays J Med Sci, 2015 Sep;22(5):1-6.
    PMID: 28239263
    The global emergence and dissemination of multidrug-resistant Gram-negative superbugs, particularly carbapenem-resistant Acinetobacter baumannii and Klebsiella pneumoniae, lead to the limited effectiveness of antibiotics for treating nosocomial infections. In most cases, polymyxins are the last resort therapy, and these antibiotics must be used intelligently to prolong their efficacy in clinical practice. Polymyxin B and colistin (polymyxin E) were introduced prior to modern drug regulation, and the majority of the 'old' drug information is unreliable. Recent pharmacokinetic data do not support the renal dose adjustment of intravenous (IV) polymyxin B as suggested by the manufacturer, and this drug must be scaled by the total body weight. Whereas IV colistin is formulated as an inactive prodrug, colistin methanesulfonate (CMS) has different pharmacokinetic profiles than polymyxin B. To achieve maximum efficacy, CMS should be administered as a loading dose scaled to body weight and a maintenance dose according to the renal profiles. Polymyxin combination therapy is suggested due to a sub-therapeutic plasma concentration in a significant proportion of patients and a high incidence of polymyxin hetero-resistance among Gram-negative superbugs. In conclusion, polymyxins must be reserved as a last resort and should be wisely used when truly indicated.
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  6. Mupirocin resistance among Malaysian isolates of methicillin-resistant Staphylococcus aureus
    Norazah A, Koh YT, Ghani Kamel A, Alias R, Lim VK
    Int J Antimicrob Agents, 2001 May;17(5):411-4.
    PMID: 11337230
    Four hundred methicillin-resistant Staphylococcus aureus strains (MRSA) from different geographical areas in Malaysia were tested for mupirocin susceptibility using minimum inhibitory concentration (MIC) determination. The majority of these strains (98.75%) were susceptible to mupirocin with MICs of < or = 4 mg/l. Fifty-percent of these strains had MICs of 0.125 mg/l or less while 90% of the strains had MICs of 1 mg/l or less. Mupirocin resistance was detected in five strains (1.25%) and one of these (0.25%) had an MIC of 64 mg/l and the other four strains (1%), high-level resistance with MICs > 512 mg/l. Even though the rate of mupirocin resistance in MRSA is still low in Malaysia, its presence calls for a strict policy on mupirocin usage in Malaysian hospitals.
    Matched MeSH terms: Drug Resistance, Multiple
  7. Molecular characterization of Vibrio cholerae O1 outbreak strains in Miri, Sarawak (Malaysia)
    Radu S, Vincent M, Apun K, Abdul-Rahim R, Benjamin PG, Yuherman, et al.
    Acta Trop, 2002 Aug;83(2):169-76.
    PMID: 12088858
    Bacterial resistance to various antimicrobial agents is common in area with high usage of antibiotics. In this study, the data on antimicrobial susceptibility patterns of Vibrio cholerae O1 from patients during an outbreak period was found to be high but variable rates of multidrug resistance. Thirty-two of 33 V. cholerae isolates harboured the tcp, ctx, zot and ace genes, suggesting their possible roles in the outbreak cases. We analyzed the molecular diversity of a total of 33 strains of V. cholerae O1 isolated from 33 patients between November 1997 and April 1998 using random amplified polymorphic DNA (RAPD) analysis. The 30 typable isolates could be separated into four major clusters containing 5, 17, 2 and 6 isolates, respectively. However, no particular RAPD pattern was predictive of a particular pattern of antibiotic susceptibility. The findings of this study showed that multiple clones seemed to be responsible for cases in the outbreaks in the study area.
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  8. Prevalence and resistance to antibiotics for Aeromonas species from retail fish in Malaysia
    Radu S, Ahmad N, Ling FH, Reezal A
    Int J Food Microbiol, 2003 Mar 25;81(3):261-6.
    PMID: 12485753
    A total of 87 market fish samples representing five types of fish were evaluated for the presence of Aeromonas spp. Of the samples examined, 69%, 55%, 11.5% and 2.3% harbored Aeromonas spp., A. veronii biovar sobria, A. hydrophila and A. caviae, respectively. The 60 isolated Aeromonas spp. strains were further examined for hemolytic activity, resistance to antimicrobial agents and presence of plasmids. Hemolytic activity varied widely among the isolated strains. Though all the isolates demonstrated resistance to three or more of the antibiotics tested, all were susceptible to ceptazidime. Thirty-four (56.7%) of the sixty isolates harbored plasmids, with sizes ranging from 2.3 to 15.7 kb. These results indicate that hemolytic, multiple antibiotic resistant and genetically diverse aeromonads are easily recovered from fish in this region.
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  9. Phenotypic evaluation of ESBL- and carbapenemaseproducing Escherichia coli and Klebsiella pneumoniae from a teaching hospital in the Philippines
    Tiongco RE, Arceo E, Dizon D, Navarro A, Rivera N, Salita C, et al.
    Trop Biomed, 2018 Dec 01;35(4):1064-1074.
    PMID: 33601853
    Antimicrobial resistance is a worldwide public health concern. Rise in the number of antimicrobial resistant organisms, such as extended spectrum β-lactamase- (ESBL) and carbapenemase-producing Escherichia coli and Klebsiella pneumoniae, continue to burden millions of people worldwide. E. coli and K. pneumoniae were isolated and collected for four months from a teaching hospital in the Philippines. All isolates were subjected to ESBL and carbapenemase testing using the double disk synergy test and modified Hodge test, respectively. Their pattern of resistance among different classes of antimicrobial agents was also investigated using the Kirby-Bauer disk diffusion test. Among the 32 clinical isolates tested, 28.1% were positive for ESBL production and 6.3% were positive for carbapenemase production. Species-specific classification showed that E. coli (44.4%) has the highest rate of ESBL production whereas both E. coli (5.6%) and K. pneumoniae (7.1%) showed almost similar rates of carbapenemase production. Antimicrobial resistance pattern of drug resistant isolates showed that all organisms were resistant to ampicillin, and majority showed resistance towards ciprofloxacin, cefotaxime, ceftriaxone, and sulfamethoxazole/trimethoprim. ESBL production is seen highest among E. coli isolates while similar rates of carbapenemase production was observed to both E. coli and K. pneumoniae isolates. Overall, antimicrobial resistance continues to rise and poses a huge threat in public health worldwide. Efforts should be made in developing rapid tests for antimicrobial resistance and to search for effective treatment from infections caused by multidrug resistant organisms.
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  10. Fulltext Phenotypic Antimicrobial Susceptibility of Escherichia coli from Raw Meats, Ready-to-Eat Meats, and Their Related Samples in One Health Context
    Adzitey F, Huda N, Shariff AHM
    Microorganisms, 2021 Feb 05;9(2).
    PMID: 33562804 DOI: 10.3390/microorganisms9020326
    Meat is an important food source that can provide a significant amount of protein for human development. The occurrence of bacteria that are resistant to antimicrobials in meat poses a public health risk. This study evaluated the occurrence and antimicrobial resistance of E. coli (Escherichia coli) isolated from raw meats, ready-to-eat (RTE) meats and their related samples in Ghana. E. coli was isolated using the USA-FDA Bacteriological Analytical Manual and phenotypic antimicrobial susceptibility test was performed by the disk diffusion method. Of the 200 examined meats and their related samples, 38% were positive for E. coli. Notably, E. coli was highest in raw beef (80%) and lowest in RTE pork (0%). The 45 E. coli isolates were resistant ≥ 50% to amoxicillin, trimethoprim and tetracycline. They were susceptible to azithromycin (87.1%), chloramphenicol (81.3%), imipenem (74.8%), gentamicin (72.0%) and ciprofloxacin (69.5%). A relatively high intermediate resistance of 33.0% was observed for ceftriaxone. E. coli from raw meats, RTE meats, hands of meat sellers and working tools showed some differences and similarities in their phenotypic antimicrobial resistance patterns. Half (51.1%) of the E. coli isolates exhibited multidrug resistance. The E. coli isolates showed twenty-two different resistant patterns, with a multiple antibiotic resistance index of 0.0 to 0.7. The resistant pattern amoxicillin (A, n = 6 isolates) and amoxicillin-trimethoprim (A-TM, n = 6 isolates) were the most common. This study documents that raw meats, RTE meats and their related samples in Ghana are potential sources of antimicrobial-resistant E. coli and pose a risk for the transfer of resistant bacteria to the food chain, environment and humans.
    Matched MeSH terms: Drug Resistance, Multiple
  11. Fulltext Pediatric osteomyelitis due to rare tropical multi-drug resistance (MDR) organisms: a treatment quandary
    Er CJ, Chun WK, Chiang LM, Nasir MNBM
    Rev Inst Med Trop Sao Paulo, 2021;63:e7.
    PMID: 33533810 DOI: 10.1590/S1678-9946202163007
    Osteomyelits due to concurrent multi-drug resistance organisms is difficult to treat for any surgeon and infectious disease physician. An eleven-year-old boy presenting with an open fracture of the left radius and ulna after a fall in a stagnant wet field. Despite prophylactic antibiotics and surgical intervention, the open wound was infected, and Chromobacterium violaceum as well as Klebsiella pneumoniae were isolated. He was treated with six weeks of parenteral cefepime and amikacin and was discharged upon clinical improvement. Unfortunately, chronic osteomyelitis set in with persistent sinus drainage. He then underwent a second procedure for debridement of the wound and Burkholderia pseudomallei was isolated. Parenteral antibiotic therapy was initiated progressing with a marked improvement. However, the long course of antibiotics had exhausted the patient and his family, leading to a premature interruption of the parenteral antibiotic. Despite the suboptimal antibiotic course, there were no signs of relapsed osteomyelitis during subsequent review. The timely surgical intervention with appropriate sampling for subsequent microorganism isolation guided the suitability of the treatment line.
    Matched MeSH terms: Drug Resistance, Multiple
  12. 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: Drug Resistance, Multiple, Bacterial
  13. Fulltext Tandem mass spectrometry detection of quorum sensing activity in multidrug resistant clinical isolate Acinetobacter baumannii
    Chan KG, Cheng HJ, Chen JW, Yin WF, Ngeow YF
    ScientificWorldJournal, 2014;2014:891041.
    PMID: 25101326 DOI: 10.1155/2014/891041
    Many Proteobacteria communicate via production followed by response of quorum sensing molecules, namely, N-acyl homoserine lactones (AHLs). These molecules consist of a lactone moiety with N-acyl side chain with various chain lengths and degrees of saturation at C-3 position. AHL-dependent QS is often associated with regulation of diverse bacterial phenotypes including the expression of virulence factors. With the use of biosensor and high resolution liquid chromatography tandem mass spectrometry, the AHL production of clinical isolate A. baumannii 4KT was studied. Production of short chain AHL, namely, N-hexanoyl-homoserine lactone (C6-HSL) and N-octanoyl-homoserine lactone (C8-HSL), was detected.
    Matched MeSH terms: Drug Resistance, Multiple
  14. Combination of essential oils and antibiotics reduce antibiotic resistance in plasmid-conferred multidrug resistant bacteria
    Yap PS, Lim SH, Hu CP, Yiap BC
    Phytomedicine, 2013 Jun 15;20(8-9):710-3.
    PMID: 23537749 DOI: 10.1016/j.phymed.2013.02.013
    In this study we investigated the relationship between several selected commercially available essential oils and beta-lactam antibiotics on their antibacterial effect against multidrug resistant bacteria. The antibacterial activity of essential oils and antibiotics was assessed using broth microdilution. The combined effects between essential oils of cinnamon bark, lavender, marjoram, tea tree, peppermint and ampicillin, piperacillin, cefazolin, cefuroxime, carbenicillin, ceftazidime, meropenem, were evaluated by means of the checkerboard method against beta-lactamase-producing Escherichia coli. In the latter assays, fractional inhibitory concentration (FIC) values were calculated to characterize interaction between the combinations. Substantial susceptibility of the bacteria toward natural antibiotics and a considerable reduction in the minimum inhibitory concentrations (MIC) of the antibiotics were noted in some paired combinations of antibiotics and essential oils. Out of 35 antibiotic-essential oil pairs tested, four of them showed synergistic effect (FIC≤0.5) and 31 pairs showed no interaction (FIC>0.5-4.0). The preliminary results obtained highlighted the occurrence of a pronounced synergistic relationship between piperacillin/cinnamon bark oil, piperacillin/lavender oil, piperacillin/peppermint oil as well as meropenem/peppermint oil against two of the three bacteria under study with a FIC index in the range 0.26-0.5. The finding highlighted the potential of peppermint, cinnamon bark and lavender essential oils being as antibiotic resistance modifying agent. Reduced usage of antibiotics could be employed as a treatment strategy to decrease the adverse effects and possibly to reverse the beta-lactam antibiotic resistance.
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  15. Analysis and construction of pathogenicity island regulatory pathways in Salmonella enterica serovar Typhi
    Ong SY, Ng FL, Badai SS, Yuryev A, Alam M
    J Integr Bioinform, 2010;7(1).
    PMID: 20861532 DOI: 10.2390/biecoll-jib-2010-145
    Signal transduction through protein-protein interactions and protein modifications are the main mechanisms controlling many biological processes. Here we described the implementation of MedScan information extraction technology and Pathway Studio software (Ariadne Genomics Inc.) to create a Salmonella specific molecular interaction database. Using the database, we have constructed several signal transduction pathways in Salmonella enterica serovar Typhi which causes Typhoid Fever, a major health threat especially in developing countries. S. Typhi has several pathogenicity islands that control rapid switching between different phenotypes including adhesion and colonization, invasion, intracellular survival, proliferation, and biofilm formation in response to environmental changes. Understanding of the detailed mechanism for S. Typhi survival in host cells is necessary for development of efficient detection and treatment of this pathogen. The constructed pathways were validated using publically available gene expression microarray data for Salmonella.
    Matched MeSH terms: Drug Resistance, Multiple
  16. Leuconicines A-G and (-)-eburnamaline, biologically active strychnan and eburnan alkaloids from Leuconotis
    Gan CY, Low YY, Etoh T, Hayashi M, Komiyama K, Kam TS
    J Nat Prod, 2009 Dec;72(12):2098-103.
    PMID: 20035556 DOI: 10.1021/np900576b
    Seven new indole alkaloids of the Strychnos type, leuconicines A-G (1-7), and a new eburnan alkaloid, (-)-eburnamaline (8), were isolated from the stem-bark extract of two Malayan Leuconotis species. The structures of these alkaloids were established using NMR and MS analysis and in the case of 8 also by partial synthesis. Alkaloids 1-5 reversed multidrug resistance in vincristine-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Multiple
  17. Rectal microscopy in men - expensive, time consuming and inappropriate
    Waters L, Worthen E, O'mahony C
    Int J STD AIDS, 2006 Oct;17(10):710.
    PMID: 17059644
    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  18. Fulltext Virulence gene profiles and antimicrobial susceptibility of Salmonella Brancaster from chicken
    Khoo E, Roslee R, Zakaria Z, Ahmad NI
    J Vet Sci, 2023 Nov;24(6):e82.
    PMID: 38031519 DOI: 10.4142/jvs.23053
    BACKGROUND: The current conventional serotyping based on antigen-antisera agglutination could not provide a better understanding of the potential pathogenicity of Salmonella enterica subsp. enterica serovar Brancaster. Surveillance data from Malaysian poultry farms indicated an increase in its presence over the years.

    OBJECTIVE: This study aims to investigate the virulence determinants and antimicrobial resistance in S. Brancaster isolated from chickens in Malaysia.

    METHODS: One hundred strains of archived S. Brancaster isolated from chicken cloacal swabs and raw chicken meat from 2017 to 2022 were studied. Two sets of multiplex polymerase chain reaction (PCR) were conducted to identify eight virulence genes associated with pathogenicity in Salmonella (invasion protein gene [invA], Salmonella invasion protein gene [sipB], Salmonella-induced filament gene [sifA], cytolethal-distending toxin B gene [cdtB], Salmonella iron transporter gene [sitC], Salmonella pathogenicity islands gene [spiA], Salmonella plasmid virulence gene [spvB], and inositol phosphate phosphatase gene [sopB]). Antimicrobial susceptibility assessment was conducted by disc diffusion method on nine selected antibiotics for the S. Brancaster isolates. S. Brancaster, with the phenotypic ACSSuT-resistance pattern (ampicillin, chloramphenicol, streptomycin, sulphonamides, and tetracycline), was subjected to PCR to detect the corresponding resistance gene(s).

    RESULTS: Virulence genes detected in S. Brancaster in this study were invA, sitC, spiA, sipB, sopB, sifA, cdtB, and spvB. A total of 36 antibiogram patterns of S. Brancaster with a high level of multidrug resistance were observed, with ampicillin exhibiting the highest resistance. Over a third of the isolates displayed ACSSuT-resistance, and seven resistance genes (β-lactamase temoneira [blaTEM], florfenicol/chloramphenicol resistance gene [floR], streptomycin resistance gene [strA], aminoglycoside nucleotidyltransferase gene [ant(3″)-Ia], sulfonamides resistance gene [sul-1, sul-2], and tetracycline resistance gene [tetA]) were detected.

    CONCLUSION: Multidrug-resistant S. Brancaster from chickens harbored an array of virulence-associated genes similar to other clinically significant and invasive non-typhoidal Salmonella serovars, placing it as another significant foodborne zoonosis.

    Matched MeSH terms: Drug Resistance, Multiple, Bacterial
  19. Fulltext The Complete Sequence and Comparative Analysis of a Multidrug-Resistance and Virulence Multireplicon IncFII Plasmid pEC302/04 from an Extraintestinal Pathogenic Escherichia coli EC302/04 Indicate Extensive Diversity of IncFII Plasmids
    Ho WS, Yap KP, Yeo CC, Rajasekaram G, Thong KL
    Front Microbiol, 2015;6:1547.
    PMID: 26793180 DOI: 10.3389/fmicb.2015.01547
    Extraintestinal pathogenic Escherichia coli (ExPEC) that causes extraintestinal infections often harbor plasmids encoding fitness traits such as resistance and virulence determinants that are of clinical importance. We determined the complete nucleotide sequence of plasmid pEC302/04 from a multidrug-resistant E. coli EC302/04 which was isolated from the tracheal aspirate of a patient in Malaysia. In addition, we also performed comparative sequence analyses of 18 related IncFIIA plasmids to determine the phylogenetic relationship and diversity of these plasmids. The 140,232 bp pEC302/04 is a multireplicon plasmid that bears three replication systems (FII, FIA, and FIB) with subtype of F2:A1:B1. The plasmid is self-transmissible with a complete transfer region. pEC302/04 also carries antibiotic resistance genes such as bla TEM-1 and a class I integron containing sul1, cml and aadA resistance genes, conferring multidrug resistance (MDR) to its host, E. coli EC302/04. Besides, two iron acquisition systems (SitABCD and IutA-IucABCD) which are the conserved virulence determinants of ExPEC-colicin V or B and M (ColV/ColBM)-producing plasmids were identified in pEC302/04. Multiple toxin-antitoxin (TA)-based addiction systems (i.e., PemI/PemK, VagC/VagD, CcdA/CcdB, and Hok/Sok) and a plasmid partitioning system, ParAB, and PsiAB, which are important for plasmid maintenance were also found. Comparative plasmid analysis revealed only one conserved gene, the repA1 as the core genome, showing that there is an extensive diversity among the IncFIIA plasmids. The phylogenetic relationship of 18 IncF plasmids based on the core regions revealed that ColV/ColBM-plasmids and non-ColV/ColBM plasmids were separated into two distinct groups. These plasmids, which carry highly diverse genetic contents, are also mosaic in nature. The atypical combination of genetic materials, i.e., the MDR- and ColV/ColBM-plasmid-virulence encoding regions in a single ExPEC plasmid is rare but of clinical importance. Such phenomenon is bothersome when the plasmids are transmissible, facilitating the spread of virulence and resistance plasmids among pathogenic bacteria. Notably, certain TA systems are more commonly found in particular ExPEC plasmid types, indicating the possible relationships between certain TA systems and ExPEC pathogenesis.
    Matched MeSH terms: Drug Resistance, Multiple
  20. In Vivo Antitumor Activity of Folate-Conjugated Cholic Acid-Polyethylenimine Micelles for the Codelivery of Doxorubicin and siRNA to Colorectal Adenocarcinomas
    Amjad MW, Amin MC, Katas H, Butt AM, Kesharwani P, Iyer AK
    Mol Pharm, 2015 Dec 7;12(12):4247-58.
    PMID: 26567518 DOI: 10.1021/acs.molpharmaceut.5b00827
    Multidrug resistance poses a great challenge to cancer treatment. In order to improve the targeting and codelivery of small interfering RNA (siRNA) and doxorubicin, and to overcome multidrug resistance, we conjugated a cholic acid-polyethylenimine polymer with folic acid, forming CA-PEI-FA micelles. CA-PEI-FA exhibited a low critical micelle concentration (80 μM), small average particle size (150 nm), and positive zeta potential (+ 12 mV). They showed high entrapment efficiency for doxorubicin (61.2 ± 1.7%, w/w), forming D-CA-PEI-FA, and for siRNA, forming D-CA-PEI-FA-S. X-ray photoelectron spectroscopic analysis revealed the presence of external FA on D-CA-PEI-FA micelles. About 25% doxorubicin was released within 24 h at pH 7.4, while more than 30% release was observed at pH 5. The presence of FA enhanced micelle antitumor activity. The D-CA-PEI-FA and D-CA-PEI-FA-S micelles inhibited tumor growth in vivo. No significant differences between their in vitro cytotoxic activities or their in vivo antitumor effects were observed, indicating that the siRNA coloading did not significantly increase the antitumor activity. Histological analysis revealed that tumor tissues from mice treated with D-CA-PEI-FA or D-CA-PEI-FA-S showed the lowest cancer cell density and the highest levels of apoptosis and necrosis. Similarly, the livers of these mice exhibited the lowest level of dihydropyrimidine dehydrogenase among all treated groups. The lowest serum vascular endothelial growth factor level (VEGF) (24.4 pg/mL) was observed in mice treated with D-CA-PEI-FA-S micelles using siRNA targeting VEGF. These findings indicated that the developed CA-PEI-FA nanoconjugate has the potential to achieve targeted codelivery of drugs and siRNA.
    Matched MeSH terms: Drug Resistance, Multiple
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