Displaying publications 121 - 140 of 173 in total

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  1. Fulltext Klebsiella pneumoniae yggG gene product: a zinc-dependent metalloprotease
    Kuan CS, Wong MT, Choi SB, Chang CC, Yee YH, Wahab HA, et al.
    Int J Mol Sci, 2011;12(7):4441-55.
    PMID: 21845088 DOI: 10.3390/ijms12074441
    Klebsiella pneumoniae causes neonatal sepsis and nosocomial infections. One of the strains, K. pneumoniae MGH 78578, shows high level of resistance to multiple microbial agents. In this study, domain family, amino acid sequence and topology analyses were performed on one of its hypothetical protein, YggG (KPN_03358). Structural bioinformatics approaches were used to predict the structure and functionality of YggG protein. The open reading frame (ORF) of yggG, which was a putative metalloprotease gene, was also cloned, expressed and characterized. The ORF was PCR amplified from K. pneumoniae MGH 78578 genomic DNA and cloned into a pET14-b vector for heterologous expression in Escherichia coli. The purified YggG protein was subsequently assayed for casein hydrolysis under different conditions. This protein was classified as peptidase M48 family and subclan gluzincin. It was predicted to contain one transmembrane domain by TMpred. Optimal protein expression was achieved by induction with 0.6 mM isopropyl thiogalactoside (IPTG) at 25 °C for six hours. YggG was purified as soluble protein and confirmed to be proteolytically active under the presence of 1.25 mM zinc acetate and showed optimum activity at 37 °C and pH 7.4. We confirmed for the first time that the yggG gene product is a zinc-dependent metalloprotease.
    Matched MeSH terms: Klebsiella pneumoniae/genetics*
  2. Fulltext Wound contraction effects and antibacterial properties of Tualang honey on full-thickness burn wounds in rats in comparison to hydrofibre
    Khoo YT, Halim AS, Singh KK, Mohamad NA
    BMC Complement Altern Med, 2010;10:48.
    PMID: 20815896 DOI: 10.1186/1472-6882-10-48
    Full-thickness burn wounds require excision and skin grafting. Multiple surgical procedures are inevitable in managing moderate to severe full-thickness burns. Wound bed preparations prior to surgery are necessary in order to prevent wound infection and promote wound healing. Honey can be used to treat burn wounds. However, not all the honey is the same. This study aims to evaluate the wound contraction and antibacterial properties of locally-produced Tualang honey on managing full-thickness burn wounds in vivo.
    Matched MeSH terms: Klebsiella pneumoniae/drug effects
  3. A MALDI TOF MS-based minisequencing method for rapid detection of TEM-type extended-spectrum beta-lactamases in clinical strains of Enterobacteriaceae
    Ikryannikova LN, Shitikov EA, Zhivankova DG, Il'ina EN, Edelstein MV, Govorun VM
    J Microbiol Methods, 2008 Dec;75(3):385-91.
    PMID: 18694787 DOI: 10.1016/j.mimet.2008.07.005
    A minisequencing method based on matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS) was developed for rapid identification of single nucleotide polymorphisms at bla(TEM) gene codons 104, 164 and 238 associated with extended-spectrum activity on TEM-type beta-lactamases. The method was validated by testing the Escherichia coli and Klebsiella pneumoniae strains possessing the known bla(TEM) gene sequences.
    Matched MeSH terms: Klebsiella pneumoniae/genetics
  4. Case report post-splenectomy sepsis in thalassemic patients
    Zarina AL, Hamidah A, Zulkifli SZ, Jamal R
    Southeast Asian J. Trop. Med. Public Health, 2005 Mar;36(2):471-3.
    PMID: 15916058
    Thalassemia is the commonest hemoglobinopathy in Malaysia. Patients with thalassemia major are transfusion dependent, and a large proportion of them will require splenectomy. As this particular group of patients is immunocompromized, overwhelming sepsis is a recognized complication. We report a series of three patients who all developed intra-abdominal abscesses following splenectomy.
    Matched MeSH terms: Klebsiella pneumoniae/isolation & purification
  5. Fulltext Antimicrobial resistance among pilgrims: a retrospective study from two hospitals in Makkah, Saudi Arabia
    Haseeb A, Faidah HS, Bakhsh AR, Malki WH, Elrggal ME, Saleem F, et al.
    Int J Infect Dis, 2016 Jun;47:92-4.
    PMID: 27312582 DOI: 10.1016/j.ijid.2016.06.006
    OBJECTIVE: To identify commonly reported community-acquired organisms and antimicrobial resistance patterns exhibited by Gram-positive and Gram-negative pathogens among pilgrims visiting emergency care departments in Makkah.
    METHOD: The study was designed as a retrospective audit of all patients (pilgrims) admitted to two hospitals and residing in the city of Makkah, Saudi Arabia.
    RESULTS: Among 374 isolates, Gram-negative pathogens accounted for 280 (75%), while the remaining 94 (25%) were Gram-positive organisms. Among all isolated pathogens, the highest resistance was observed for amoxicillin-clavulanic acid. Klebsiella pneumoniae had the highest resistance to amoxicillin-clavulanic acid and ampicillin. Most of the organisms were sensitive to tobramycin except Acinetobacter baumannii (n=3, 50%), Escherichia coli (n=4, 57%), and K. pneumoniae (n=6, 46%).
    CONCLUSION: Overall, a high resistance was observed for beta-lactam antibiotics. In addition, a high resistance was noted for ceftazidime with A. baumannii species (n=16, 77%). However, for quinolones, the highest resistance to ciprofloxacin was observed for E. coli, A. baumannii, methicillin-resistant Staphylococcus aureus, and K. pneumoniae.
    KEYWORDS: Antimicrobial resistance; Community-acquired organisms; Makkah; Pilgrims
    Matched MeSH terms: Klebsiella pneumoniae/drug effects
  6. Identification of Antibacterial Molecule(s) from Animals Living in Polluted Environments
    Winnie FYM, Siddiqui R, Sagathevan K, Khan NA
    Curr Pharm Biotechnol, 2020;21(5):425-437.
    PMID: 31577204 DOI: 10.2174/1389201020666191002153435
    BACKGROUND: Snakes feed on germ-infested rodents, while water monitor lizards thrive on rotten matter in unhygienic conditions. We hypothesize that such creatures survive the assault of superbugs and are able to fend off disease by producing antimicrobial substances. In this study, we investigated the potential antibacterial activity of sera/lysates of animals living in polluted environments.

    METHODS: Snake (Reticulatus malayanus), rats (Rattus rattus), water monitor lizard (Varanus salvator), frog (Lithobates catesbeianus), fish (Oreochromis mossambicus), chicken (Gallus gallus domesticus), and pigeon (Columba livia) were dissected and their organ lysates/sera were collected. Crude extracts were tested for bactericidal effects against neuropathogenic E. coli K1, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pyogenes, Pseudomonas aeruginosa, Bacillus cereus and Klebsiella pneumoniae. To determine whether lysates/sera protect human cells against bacterialmediated damage, cytotoxicity assays were performed by measuring lactate dehydrogenase release as an indicator of cell death. Lysates/sera were partially characterized using heat-treatment and pronasetreatment and peptide sequences were determined using the Liquid Chromatography Mass Spectrometry (LC-MS).

    RESULTS: Snake and water monitor lizard sera exhibited potent broad-spectrum bactericidal effects against all bacteria tested. Heat inactivation and pronase-treatment inhibited bactericidal effects indicating that activity is heat-labile and pronase-sensitive suggesting that active molecules are proteinaceous in nature. LCMS analyses revealed the molecular identities of peptides.

    CONCLUSION: The results revealed that python that feeds on germ-infested rodents and water monitor lizards that feed on rotten organic waste possess antibacterial activity in a heat-sensitive manner and several peptides were identified. We hope that the discovery of antibacterial activity in the sera of animals living in polluted environments will stimulate research in finding antibacterial agents from unusual sources as this has the potential for the development of novel strategies in the control of infectious diseases.

    Matched MeSH terms: Klebsiella pneumoniae/drug effects
  7. Fulltext Simultaneous detection of methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa by multiplex PCR
    Thong KL, Lai MY, Teh C SJ, Chua KH
    Trop Biomed, 2011 Apr;28(1):21-31.
    PMID: 21602765 MyJurnal
    A PCR-based assay that can simultaneously detect and differentiate five different types of nosocomial bacterial pathogens was developed. Six pairs of selected primers targeting femA (132 bp) and mecA (310 bp) of methicillin-resistant Staphylococcus aureus, gltA (722 bp) of Acinetobacter baumannii, phoA (903 bp) of Escherichia coli, mdh (364 bp) of Klebsiella pneumoniae and oprL (504 bp) of Pseudomonas aeruginosa were used in this study. The conditions were optimized for the multiplex PCR to ensure specific amplification of the selected targets. Sensitivity and specificity tests were also carried out using a blind test approach on 50 bacterial cultures and resulted in 100% for both positive and negative predictive values.
    Matched MeSH terms: Klebsiella pneumoniae/isolation & purification
  8. Synthesis, spectral analysis and biological evaluation of 2-{[(morpholin-4-yl)ethyl]thio}-5-phenyl/aryl-1,3,4-oxadiazole derivatives
    Ur-Rehman A, Khan SG, Naqvi SAR, Ahmad M, Akhtar N, Bokhari TH, et al.
    Pak J Pharm Sci, 2021 Jan;34(1(Special)):441-446.
    PMID: 34275792
    A series of new derivatives of 4-(2-chloroethyl)morpholine hydrochloride (5) were efficiently synthesized. Briefly, different aromatic organic acids (1a-f) were refluxed to acquire respective esters (2a-f) using conc. H2SO4 as catalyst. The esters were subjected to nucleophillic substitution by monohydrated hydrazine to acquire hydrazides (3a-f). The hydrazides were cyclized with CS2 in the presence of KOH to yield corresponding oxadiazoles (4a-f). Finally, the derivatives, 6a-f, were prepared by reacting oxadiazoles (4a-f) with 5 using NaH as activator. Structures of all the derivatives were elucidated through 1D-NMR EI-MS and IR spectral data. All these molecules were subjected to antibacterial and hemolytic activities and showed good antibacterial and hemolytic potential relative to the reference standards.
    Matched MeSH terms: Klebsiella pneumoniae/drug effects
  9. Fulltext Variant of Lemierre's syndrome with internal jugular vein aneurysm
    Chua SH, Ong SCL, Liew YH
    BMJ Case Rep, 2017 Dec 22;2017.
    PMID: 29275396 DOI: 10.1136/bcr-2017-223371
    Internal jugular vein (IJV) aneurysm is a rare entity, and a thrombosed aneurysm poses diagnostic and management challenges. We came across a 53-year-old woman who presented with fever, vomiting and right neck swelling for a week. Laboratory investigations showed neutrophilic leucocytosis, raised acute phase reactant and blood culture yielded Klebsiella pneumoniae Ultrasound and contrast-enhanced CT neck revealed a large fusiform aneurysm of the right IJV with filling defect extending from the aneurysm into the right transverse sinus. There was a cavity at the right lower third molar tooth. MRI confirmed the findings with additional enhancing focus at right lower periodontal region. The swelling reduced after 2 weeks of medical therapy, and follow-up imaging 4 months later showed complete resolution of the aneurysm with residual thrombosis. After extensive workup, dental infection remains the only identifiable primary source leading to thrombophlebitis of the right IJV and subsequent sequelae.
    Matched MeSH terms: Klebsiella pneumoniae/isolation & purification
  10. SHV-5 extended-spectrum beta-lactamases in clinical isolates of Escherichia coli in Malaysia
    Subramaniam G, Palasubramaniam S, Navaratnam P
    Indian J Med Microbiol, 2006 Jul;24(3):205-7.
    PMID: 16912441
    Escherichia coli isolates resistant to ceftazidime isolated in the University Malaya Medical Center (UMMC) Kuala Lumpur, Malaysia, between the years 1998 and 2000 were studied for extended-spectrum beta-lactamase (ESBL) production. All strains were analysed phenotypically and genotypically and found to be ESBL-producing organisms harbouring SHV-5 beta-lactamase. This was confirmed by PCR-SSCP and nucleotide sequencing of the blaSHV amplified gene. As there was no evidence of ESBL activity in E. coli prior to this, coupled with the fact that there was a predominance of SHV-5 beta-lactamases in Klebsiella pneumoniae isolates in UMMC, we postulate that the E. coli obtained the SHV-5 beta-lactamase genes by plasmid transfer from the ESBL-producing K. pneumoniae.
    Matched MeSH terms: Klebsiella pneumoniae/genetics*
  11. Fulltext Plant Growth-Promoting Rhizobacteria Inoculation to Enhance Vegetative Growth, Nitrogen Fixation and Nitrogen Remobilisation of Maize under Greenhouse Conditions
    Kuan KB, Othman R, Abdul Rahim K, Shamsuddin ZH
    PLoS One, 2016;11(3):e0152478.
    PMID: 27011317 DOI: 10.1371/journal.pone.0152478
    Plant growth-promoting rhizobacteria (PGPR) may provide a biological alternative to fix atmospheric N2 and delay N remobilisation in maize plant to increase crop yield, based on an understanding that plant-N remobilisation is directly correlated to its plant senescence. Thus, four PGPR strains were selected from a series of bacterial strains isolated from maize roots at two locations in Malaysia. The PGPR strains were screened in vitro for their biochemical plant growth-promoting (PGP) abilities and plant growth promotion assays. These strains were identified as Klebsiella sp. Br1, Klebsiella pneumoniae Fr1, Bacillus pumilus S1r1 and Acinetobacter sp. S3r2 and a reference strain used was Bacillus subtilis UPMB10. All the PGPR strains were tested positive for N2 fixation, phosphate solubilisation and auxin production by in vitro tests. In a greenhouse experiment with reduced fertiliser-N input (a third of recommended fertiliser-N rate), the N2 fixation abilities of PGPR in association with maize were determined by 15N isotope dilution technique at two harvests, namely, prior to anthesis (D50) and ear harvest (D65). The results indicated that dry biomass of top, root and ear, total N content and bacterial colonisations in non-rhizosphere, rhizosphere and endosphere of maize roots were influenced by PGPR inoculation. In particular, the plants inoculated with B. pumilus S1r1 generally outperformed those with the other treatments. They produced the highest N2 fixing capacity of 30.5% (262 mg N2 fixed plant-1) and 25.5% (304 mg N2 fixed plant-1) of the total N requirement of maize top at D50 and D65, respectively. N remobilisation and plant senescence in maize were delayed by PGPR inoculation, which is an indicative of greater grain production. This is indicated by significant interactions between PGPR strains and time of harvests for parameters on N uptake and at. % 15Ne of tassel. The phenomenon is also supported by the lower N content in tassels of maize treated with PGPR, namely, B. pumilus S1r1, K. pneumoniae Fr1, B. subtilis UPMB10 and Acinetobacter sp. S3r2 at D65 harvest. This study provides evidence that PGPR inoculation, namely, B. pumilus S1r1 can biologically fix atmospheric N2 and provide an alternative technique, besides plant breeding, to delay N remobilisation in maize plant for higher ear yield (up to 30.9%) with reduced fertiliser-N input.
    Matched MeSH terms: Klebsiella pneumoniae*
  12. Fulltext Development of conventional and real-time multiplex PCR assays for the detection of nosocomial pathogens
    Anbazhagan D, Mui WS, Mansor M, Yan GO, Yusof MY, Sekaran SD
    Braz J Microbiol, 2011 Apr;42(2):448-58.
    PMID: 24031653 DOI: 10.1590/S1517-83822011000200006
    Nosocomial infections are major clinical threats to hospitalised patients and represent an important source of morbidity and mortality. It is necessary to develop rapid detection assays of nosocomial pathogens for better prognosis and initiation of antimicrobial therapy in patients. In this study, we present the development of molecular methods for the detection of six common nosocomial pathogens including Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. Conventional multiplex PCR and SYBR Green based real time PCR assays were performed using genus and species specific primers. Blind testing with 300 clinical samples was also carried out. The two assays were found to be sensitive and specific. Eubacterial PCR assay exhibited positive results for 46 clinical isolates from which 43 samples were detected by real time PCR assay. The sensitivity of the assay is about 93.7% in blind test isolates. The PCR results were reconfirmed using the conventional culture method. This assay has the potential to be a rapid, accurate and highly sensitive molecular diagnostic tool for simultaneous detection of Escherichia coli, Staphylococcus aureus, Streptococcus pneumoniae, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter spp. This assay has the potential to detect nosocomial pathogens within 5 to 6 hours, helping to initiate infection control measures and appropriate treatment in paediatric and elderly (old aged) patients, pre-and post surgery patients and organ transplant patients and thus reduces their hospitalization duration.
    Matched MeSH terms: Klebsiella pneumoniae
  13. Fulltext Antimicrobial activity and the presence of virulence factors and bacteriocin structural genes in Enterococcus faecium CM33 isolated from ewe colostrum
    Nami Y, Haghshenas B, Haghshenas M, Yari Khosroushahi A
    Front Microbiol, 2015;6:782.
    PMID: 26284059 DOI: 10.3389/fmicb.2015.00782
    Screening of lactic acid bacteria (LAB) isolated from ewe colostrum led to the identification and isolation of Enterococcus faecium CM33 with interesting features like high survival rates under acidic or bile salts condition, high tolerance for the simulated gastrointestinal condition, and high adhesive potential to Caco-2 cells. According the inhibition of pathogen adhesion test results, this strain can reduce more than 50% adhesion capacity of Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, Listeria monocytogenes, and Staphylococcus aureus to Caco-2 cells. Based on the antibiotic sensitivity test findings, E. faecium CM33 was susceptible to gentamycin, vancomycin, erythromycin, ampicillin, penicillin, tetracycline, and rifampicin, but resistant to chloramphenicol, clindamycin, and kanamycin. Upon assessment of the virulence determinants for E. faecium CM33, this strain was negative for all tested virulence genes. Furthermore, the genome of this strain was evaluated for the incidence of the known enterocin genes by specific PCR amplification and discovered the genes encoding enterocins A, 31, X, and Q. Based on this study findings, the strain E. faecium CM33 can be considered as a valuable nutraceutical and can be introduced as a new potential probiotic.
    Matched MeSH terms: Klebsiella pneumoniae
  14. Burden of bacterial meningitis: a retrospective review on laboratory parameters and factors associated with death in meningitis, kelantan malaysia
    Basri R, Zueter AR, Mohamed Z, Alam MK, Norsa'adah B, Hasan SA, et al.
    Nagoya J Med Sci, 2015 Feb;77(1-2):59-68.
    PMID: 25797971
    To describe the clinical characteristics and the risk factors associated with mortality in patients with meningitis. This is a retrospective review of patients diagnosed to have meningitis with positive culture of the cerebrospinal fluid (CSF) specimen. All cases aged 19 > years who were admitted to Hospital USM between January 2004 and December 2011 were included in the study. The CSF results database were obtained from the Department of Medical Microbiology and Parasitology, Hospital USM, Kelantan. A checklist was used to record the clinical characteristics. A total of 125 cases met the inclusion criteria. The age of patients ranged between newborn and 19 years old (Mean±SD, 74.5±80.6 months). The majority of them were males (65.6%). Fever was the most common presentation (73.6%) followed by poor oral intake (48.0%), seizure (36.0%) and headache (24.8%). The mortality rate was 31.2%. Coagulase negative staphylococcus was the most frequent pathogens isolated (21.6%), followed by Acinetobacter spp. (17.6%), Staphylococcus aureus (13.6%), Streptococcus spp. (11.2%) and Klebsiella pneumoniae (6.4%). There were significant association of in-hospital death with age (p=0.020) and conscious level (p=0.001). Infectious meningitis is a big health concern, especially among children. We found that coagulase negative staphylococcus, Acinetobacter species, S. aureus, Streptococcus spp and K. pneumoniae were prevalent in our hospital. These microorganisms were hospital associated pathogens. The 31% mortality linked to hospital acquired meningitis specifies the need for focused physician attention especially among younger aged patients.
    Matched MeSH terms: Klebsiella pneumoniae
  15. Fulltext Genotypic to Phenotypic Resistance Discrepancies Identified Involving β-Lactamase Genes, blaKPC, blaIMP, blaNDM-1, and blaVIM in Uropathogenic Klebsiella pneumoniae
    Urmi UL, Nahar S, Rana M, Sultana F, Jahan N, Hossain B, et al.
    Infect Drug Resist, 2020;13:2863-2875.
    PMID: 32903880 DOI: 10.2147/IDR.S262493
    Introduction: Klebsiella pneumoniae carbapenemase (KPC) belongs to the Group-A β-lactamases that incorporate serine at their active site and hydrolyze various penicillins, cephalosporins, and carbapenems. Metallo-beta-lactamases (MBLs) are group-B enzymes that contain one or two essential zinc ions in the active sites and hydrolyze almost all clinically available β-lactam antibiotics. Klebsiella pneumoniae remains the pathogen with the most antimicrobial resistance to KPC and MBLs.

    Methods: This research investigated the blaKPC, and MBL genes, namely, blaIMP, blaVIM, and blaNDM-1 and their phenotypic resistance to K. pneumoniae isolated from urinary tract infections (UTI) in Bangladesh. Isolated UTI K. pneumoniae were identified by API-20E and 16s rDNA gene analysis. Their phenotypic antimicrobial resistance was examined by the Kirby-Bauer disc diffusion method, followed by minimal inhibitory concentration (MIC) determination. blaKPC, blaIMP, blaNDM-1, and blaVIM genes were evaluated by polymerase chain reactions (PCR) and confirmed by sequencing.

    Results: Fifty-eight K. pneumoniae were identified from 142 acute UTI cases. Their phenotypic resistance to amoxycillin-clavulanic acid, cephalexin, cefuroxime, ceftriaxone, and imipenem were 98.3%, 100%, 96.5%, 91.4%, 75.1%, respectively. Over half (31/58) of the isolates contained either blaKPC or one of the MBL genes. Individual prevalence of blaKPC, blaIMP, blaNDM-1, and blaVIM were 15.5% (9), 10.3% (6), 22.4% (13), and 19% (11), respectively. Of these, eight isolates (25.8%, 8/31) were found to have two genes in four different combinations. The co-existence of the ESBL genes generated more resistance than each one individually. Some isolates appeared phenotypically susceptible to imipenem in the presence of blaKPC, blaIMP, blaVIM, and blaNDM-1 genes, singly or in combination.

    Conclusion: The discrepancy of genotype and phenotype resistance has significant consequences for clinical bacteriology, precision in diagnosis, the prudent selection of antimicrobials, and rational prescribing. Heterogeneous phenotypes of antimicrobial susceptibility testing should be taken seriously to avoid inappropriate diagnostic and therapeutic decisions.

    Matched MeSH terms: Klebsiella pneumoniae
  16. The bactericidal potential of LLDPE with TiO2/ZnO nanocomposites against multidrug resistant pathogens associated with hospital acquired infections
    Harun NH, Mydin RBSMN, Sreekantan S, Saharudin KA, Basiron N, Seeni A
    J Biomater Sci Polym Ed, 2020 10;31(14):1757-1769.
    PMID: 32498665 DOI: 10.1080/09205063.2020.1775759
    The emerging polymer nanocomposites have received industrial interests in diverse fields because of their added value in metal oxide-based nanocomposites, such as titanium (TiO2) and zinc oxide (ZnO). Linear low-density polyethylene (LLDPE)-based polymer has recently generated a huge market in the healthcare industry. TiO2 and ZnO are well known for their instant photocatalytic killing of hospital-acquired infections, especially multidrug-resistant (MDR) pathogens. This study investigated the actions of LLDPE/TiO2/ZnO (1:3) nanocomposites in different weight% against two representative MDR pathogens, namely, methicillin-resistant Staphylococcus aureus (MRSA) and Klebsiella pneumonia (K.pneumoniae). Antibacterial activities were quantified according to international standard guidelines of CLSI MO2-A11 (static condition) and ASTM E-2149 (dynamic condition). Preliminary observation via a scanning electron microscope revealed that LLDPE matrix with TiO2/ZnO nanocomposites changed the bacterial morphology and reduced the bacterial adherence and biofilm formation. Furthermore, a high ZnO weight ratio killed both types of pathogens. The bactericidal potential of the nanocomposite is highlighted by the enhancements in photocatalytic activity, zinc ion release and reactive species, and bacteriostatic/bactericidal activity against bacterial growth. This study provides new insights into the MDR-bactericidal potential of LLDPE with TiO2/ZnO nanocomposites for targeted healthcare applications.
    Matched MeSH terms: Klebsiella pneumoniae
  17. Fulltext Design, synthesis and therapeutic potential of 3-(2-(1H-benzo[d]imidazol-2-ylthio)acetamido)-N-(substituted phenyl)benzamide analogues
    Tahlan S, Ramasamy K, Lim SM, Shah SAA, Mani V, Narasimhan B
    Chem Cent J, 2018 Dec 19;12(1):139.
    PMID: 30569392 DOI: 10.1186/s13065-018-0513-3
    BACKGROUND: The emergence of bacterial resistance is a major public health problem. It is essential to develop and synthesize new therapeutic agents with better activity. The mode of actions of certain newly developed antimicrobial agents, however, exhibited very limited effect in treating life threatening systemic infections. Therefore, the advancement of multi-potent and efficient antimicrobial agents is crucial to overcome the increased multi-drug resistance of bacteria and fungi. Cancer, which remains as one of the primary causes of deaths and is commonly treated by chemotherapeutic agents, is also in need of novel and efficacious agents to treat resistant cases. As such, a sequence of novel substituted benzamides was designed, synthesized and evaluated for their antimicrobial and anticancer activities.

    METHODOLOGY: All synthesized compounds were characterized by IR, NMR, Mass and elemental analysis followed by in vitro antimicrobial studies against Gram-positive (Staphylococcus aureus), Gram-negative (Salmonella typhi and Klebsiella pneumoniae) bacterial and fungal (Candida albicans and Aspergillus niger) strains by the tube dilution method. The in vitro anticancer evaluation was carried out against the human colorectal carcinoma cell line (HCT116), using the Sulforhodamine B assay.

    RESULTS, DISCUSSION AND CONCLUSION: Compound W6 (MICsa, st, kp = 5.19 µM) emerged as a significant antibacterial agent against all tested bacterial strains i.e. Gram-positive (S. aureus), Gram-negative (S. typhi, K. pneumoniae) while compound W1 (MICca, an = 5.08 µM) was most potent against fungal strains (A. niger and C. albicans) and comparable to fluconazole (MIC = 8.16 µM). The anticancer screening demonstrated that compound W17 (IC50 = 4.12 µM) was most potent amongst the synthesized  compounds and also more potent than the standard drug 5-FU (IC50 = 7.69 µM).

    Matched MeSH terms: Klebsiella pneumoniae
  18. Fulltext Gut Bacteria of Water Monitor Lizard (Varanus salvator) Are a Potential Source of Antibacterial Compound(s)
    Akbar N, Siddiqui R, Sagathevan K, Iqbal M, Khan NA
    Antibiotics (Basel), 2019 Sep 24;8(4).
    PMID: 31554316 DOI: 10.3390/antibiotics8040164
    For the past few decades, there has been limited progress in the development of novel antibacterials. Previously, we postulated that the gut microbiota of animals residing in polluted environments are a forthcoming supply of antibacterials. Among various species, the water monitor lizard is an interesting species that feeds on organic waste and the carcass of wild animals. Gut microbiota of the water monitor lizard were sequestered, identified and cultivated in RPMI-1640 to produce conditioned medium (CM). Next, the antimicrobial properties of CM were evaluated versus a selection of Gram-negative (Escherichia coli K1, Serratia marcescens,Pseudomonas aeruginosa, Salmonella enterica and Klebsiella pneumoniae) and Gram-positive bacteria (Streptococcus pyogenes, methicillin-resistant Staphylococcus aureus, and Bacillus cereus). CM were partially characterized by heat inactivation at 95°C for 10 min and tested against P. aeruginosa and S. pyogenes. CM were also tested against immortalized human keratinocytes (HaCaT) cells lines. The results demonstrated that gut microbiota isolated from water monitor lizard produced molecules with remarkable bactericidal activities. To determine the identity of the active molecules, CM were subjected to Liquid Chromatography-Mass Spectrometry. Several molecules were identified belonging to the classes of flavonoids, terpenoids, alkaloids, polyhydroxy alkaloids, polyacetylenes, bisphenols, amides, oxylipin and pyrazine derivatives with known broad-spectrum antimicrobial, anti-tumour, anti-oxidant, anti-inflammatory, and analgesic attributes. Furthermore, the detailed analysis of these molecules could lead us to develop effective therapeutic antibacterials.
    Matched MeSH terms: Klebsiella pneumoniae
  19. Fulltext In Vitro Efficacy of Flomoxef against Extended-Spectrum Beta-Lactamase-Producing Escherichia coli and Klebsiella pneumoniae Associated with Urinary Tract Infections in Malaysia
    Ngoi ST, Teh CSJ, Chong CW, Abdul Jabar K, Tan SC, Yu LH, et al.
    Antibiotics (Basel), 2021 Feb 11;10(2).
    PMID: 33670224 DOI: 10.3390/antibiotics10020181
    The increasing prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae has greatly affected the clinical efficacy of β-lactam antibiotics in the management of urinary tract infections (UTIs). The limited treatment options have resulted in the increased use of carbapenem. However, flomoxef could be a potential carbapenem-sparing strategy for UTIs caused by ESBL-producers. Here, we compared the in vitro susceptibility of UTI-associated ESBL-producers to flomoxef and established β-lactam antibiotics. Fifty Escherichia coli and Klebsiella pneumoniae strains isolated from urine samples were subjected to broth microdilution assay, and the presence of ESBL genes was detected by polymerase chain reactions. High rates of resistance to amoxicillin-clavulanate (76-80%), ticarcillin-clavulanate (58-76%), and piperacillin-tazobactam (48-50%) were observed, indicated by high minimum inhibitory concentration (MIC) values (32 µg/mL to 128 µg/mL) for both species. The ESBL genes blaCTX-M and blaTEM were detected in both E. coli (58% and 54%, respectively) and K. pneumoniae (88% and 74%, respectively), whereas blaSHV was found only in K. pneumoniae (94%). Carbapenems remained as the most effective antibiotics against ESBL-producing E. coli and K. pneumoniae associated with UTIs, followed by flomoxef and cephamycins. In conclusion, flomoxef may be a potential alternative to carbapenem for UTIs caused by ESBL-producers in Malaysia.
    Matched MeSH terms: Klebsiella pneumoniae
  20. Fulltext Combinatorial Antimicrobial Efficacy and Mechanism of Linalool Against Clinically Relevant Klebsiella pneumoniae
    Yang SK, Yusoff K, Ajat M, Wee CY, Yap PS, Lim SH, et al.
    Front Microbiol, 2021;12:635016.
    PMID: 33815320 DOI: 10.3389/fmicb.2021.635016
    Antibiotic-adjuvant combinatory therapy serves as a viable treatment option in addressing antibiotic resistance in the clinical setting. This study was carried out to assess and characterize the adjuvant potential and mode of action of linalool against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). Linalool exhibited bactericidal activity alone (11,250 μg/ml) and in combination with meropenem (5,625 μg/ml). Comparative proteomic analysis showed significant reduction in the number of cytoplasmic and membrane proteins, indicating membrane damage in linalool-treated KPC-KP cells. Upregulation of oxidative stress regulator proteins and downregulation of oxidative stress-sensitive proteins indicated oxidative stress. Zeta potential measurement and outer membrane permeability assay revealed that linalool increases the bacterial surface charge as well as the membrane permeability. Intracellular leakage of nucleic acid and proteins was detected upon linalool treatment. Scanning and transmission electron microscopies further revealed the breakage of bacterial membrane and loss of intracellular materials. Linalool induced oxidative stress by generating reactive oxygen species (ROS) which initiates lipid peroxidation, leading to damage of the bacterial membrane. This leads to intracellular leakage, eventually killing the KPC-KP cells. Our study demonstrated that linalool possesses great potential in future clinical applications as an adjuvant along with existing antibiotics attributed to their ability in disrupting the bacterial membrane by inducing oxidative stress. This facilitates the uptake of antibiotics into the bacterial cells, enhancing bacterial killing.
    Matched MeSH terms: Klebsiella pneumoniae
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