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Six-year multicenter study on short-term peripheral venous catheters-related bloodstream infection rates in 727 intensive care units of 268 hospitals in 141 cities of 42 countries of Africa, the Americas, Eastern Mediterranean, Europe, South East Asia, and Western Pacific Regions: International Nosocomial Infection Control Consortium (INICC) findings

Rosenthal VD, Bat-Erdene I, Gupta D, Belkebir S, Rajhans P, Zand F, et al.

Infect Control Hosp Epidemiol, 2020 05;41(5):553-563.
PMID: 32183925 DOI: 10.1017/ice.2020.20

BACKGROUND: Short-term peripheral venous catheter-related bloodstream infection (PVCR-BSI) rates have not been systematically studied in resource-limited countries, and data on their incidence by number of device days are not available.
METHODS: Prospective, surveillance study on PVCR-BSI conducted from September 1, 2013, to May 31, 2019, in 727 intensive care units (ICUs), by members of the International Nosocomial Infection Control Consortium (INICC), from 268 hospitals in 141 cities of 42 countries of Africa, the Americas, Eastern Mediterranean, Europe, South East Asia, and Western Pacific regions. For this research, we applied definition and criteria of the CDC NHSN, methodology of the INICC, and software named INICC Surveillance Online System.
RESULTS: We followed 149,609 ICU patients for 731,135 bed days and 743,508 short-term peripheral venous catheter (PVC) days. We identified 1,789 PVCR-BSIs for an overall rate of 2.41 per 1,000 PVC days. Mortality in patients with PVC but without PVCR-BSI was 6.67%, and mortality was 18% in patients with PVC and PVCR-BSI. The length of stay of patients with PVC but without PVCR-BSI was 4.83 days, and the length of stay was 9.85 days in patients with PVC and PVCR-BSI. Among these infections, the microorganism profile showed 58% gram-negative bacteria: Escherichia coli (16%), Klebsiella spp (11%), Pseudomonas aeruginosa (6%), Enterobacter spp (4%), and others (20%) including Serratia marcescens. Staphylococcus aureus were the predominant gram-positive bacteria (12%).
CONCLUSIONS: PVCR-BSI rates in INICC ICUs were much higher than rates published from industrialized countries. Infection prevention programs must be implemented to reduce the incidence of PVCR-BSIs in resource-limited countries.

Matched MeSH terms: Klebsiella
Fulltext Diagnostic use of PCR in Carbapenamase-producing Enterobacteriaceae (CPE): An mproved method to overcome the presence of inhibitors for DNA extraction from blood cultures

Zeti Norfidiyati Salmuna, Murnihayati Hassan, Habsah Hasan, Zakuan Zainy Deris

Malaysian Journal of Medicine and Health Sciences, 2019;15(1):1-4.
MyJurnal

Carpanenamase-producing Enterobacteriaceae (CPE) has emerged as a threat to hospitalized patients. Phenotypic test such as Modified hodge test was less sensitive and specific especially to detect blaNDM-1 which is the most predominant genotype in this region. Nucleic acid amplification technology offers improved specificity and sensitivity. Failed amplification due to the presence of inhibitors is a limitation. In this study, we tried to use previous method described by Villumseen et al with some modification using another DNA extraction kit. Methods: Ten mls of sterile whole blood taken from nearly expired blood bag from blood bank was spiked with 200 μl of 0.5mcFarland bacterial suspension from thirty-six confirmed isolates of blaNDM-1 carbapenamase-producing Klebsiella pneumoniae in an aerobic Bactec Plus and incubated until the growth was detected. The blood specimen was subjected to DNA extraction method using Macherey-Nachel, Nucleospin® Blood QuickPure followed with multiplex PCR. Results: Out of the 36 isolates, 12 isolates revealed blaNDM-1 , 9 isolates revealed blaNDM-1 and blaOXA-48, 7 isolates revealed blaNDM-1, blaVIM and blaKPC genotypes that were amplified at cycle threshold of less than 30. Another 8 isolates could not pick up any genotypes possibly due to pipetting error as all the internal control were amplified. Eight true negative gram negative isolates underwent same procedure and none amplified at a cycle threshold less than 30. Conclusion: This modified method was proved to give a high yield of CPE genotypes with the cycle threshold was set at less than or equal to 30 and able to overcome the presence of PCR inhibitors.

Matched MeSH terms: Klebsiella pneumoniae
Inhibition of Klebsiella pneumoniae ATCC 13883 cells by hexane extract of Halimeda discoidea (Decaisne) and the identification of its potential bioactive compounds

Supardy NA, Ibrahim D, Sulaiman SF, Zakaria NA

J Microbiol Biotechnol, 2012 Jun;22(6):872-81.
PMID: 22573167

The inhibitory effect of the Klebsiella pneumoniae ATCC 13883 strain caused by the hexane extract of Halimeda discoidea (Nor Afifah et al., 2010) was further evaluated by means of the microscopy view and its growth curves. The morphological changes of the K. pneumoniae ATCC 13883 cells were observed under the scanning electron microscope (SEM) and transmission electron microscope (TEM) after they were treated at minimum inhibitory concentration (MIC; 0.50 mg/ml) (Nor Afifah et al., 2010) for 12, 24, and 36 h. The results showed the severity of the morphological deteriorations experienced by the treated cells. The killing curve assay was performed for 48 h at three different extract concentrations (1/2 MIC, MIC, and 2 MIC). An increase in the extract concentration of up to 2 MIC value did significantly reduce the number of cells by approximately 1.9 log10, as compared with the control. Identification of the potential compounds of the extract responsible for the antibacterial activity was carried out through the gas chromatography-mass spectrum (GCMS) analysis of the active subfraction, and the compound E-15-heptadecenal was identified and suggested as the most potential antibacterial compound of this extract. The subsequent cellular degenerations showed by the data might well explain the inhibitory mechanisms of the suggested antibacterial compound. All of these inhibitory effects have further proven the presence of an antibacterial compound within H. discoidea that can inhibit the growth of K. pneumoniae ATCC 13883.

Matched MeSH terms: Klebsiella pneumoniae/drug effects*; Klebsiella pneumoniae/growth & development; Klebsiella pneumoniae/ultrastructure
Fulltext Dual bioactivities of laurus nobilis essential oil

Nur Afiqah Saparin, Mohd Muzamir Mahat, Muhd Fauzi Safian, Shahrul Hisham Zainal Ariffin, Nor Azah Mohamad Ali, Zaidah Zainal Ariffin

Science Letters, 2020;14(1):62-67.
MyJurnal

The evolution of cosmetic products results in the growing demands for cosmetics that are preservatives free. Plant essential oils were found to be a promising antimicrobial and also antioxidant agent. In this study, Cymbopogon citratus (lemongrass), Laurus nobilis (bay leaf) and Backhousia citriodora (lemon myrtle) essential oils were selected and evaluated for their antimicrobial properties. It was found that Laurus nobilis exhibited strong antimicrobial activity against the selected bacteria Streptococcus saprophyticus (ATCC 49619), Streptococcus aureus (ATCC 22923), Streptococcus pyogenes (ATCC 29436), Pseudomonas aeruginosa (ATCC 13048), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 22922) with MIC ranging between 7.8 ug/mL to 250 μg/mL. The antioxidant activity of selected essential oils was determined by antioxidant assays which were 1,1-Diphenyl-2-picrylhydrazyl assay (DPPH), determination of ferric reducing antioxidant power assay (FRAP) and β-Carotene/linoleic acid bleaching assay. Backhousia citriodora and Laurus nobilis showed the highest antioxidant activity.
n-Octanal and β-Selinene were identified to be the major components with peak area of 26.37 % and 13.92 % respectively in secondary metabolites analysis by Gas Chromatography-Mass Spectrometry (GCMS).

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Klebsiella virus UPM2146 lyses multiple drug-resistant Klebsiella pneumoniae in vitro and in vivo

Assafiri O, Song AA, Tan GH, Hanish I, Hashim AM, Yusoff K

PLoS One, 2021;16(1):e0245354.
PMID: 33418559 DOI: 10.1371/journal.pone.0245354

Klebsiella pneumoniae are opportunistic bacteria found in the gut. In recent years they have been associated with nosocomial infections. The increased incidence of multiple drug-resistant K. pneumoniae makes it necessary to find new alternatives to treat the disease. In this study, phage UPM2146 was isolated from a polluted lake which can lyse its host K. pneumoniae ATCC BAA-2146. Observation from TEM shows that UPM2146 belongs to Caudoviriales (Order) based on morphological appearance. Whole genome analysis of UPM2146 showed that its genome comprises 160,795 bp encoding for 214 putative open reading frames (ORFs). Phylogenetic analysis revealed that the phage belongs to Ackermannviridae (Family) under the Caudoviriales. UPM2146 produces clear plaques with high titers of 1010 PFU/ml. The phage has an adsorption period of 4 min, latent period of 20 min, rise period of 5 min, and releases approximately 20 PFU/ bacteria at Multiplicity of Infection (MOI) of 0.001. UPM2146 has a narrow host-range and can lyse 5 out of 22 K. pneumoniae isolates (22.72%) based on spot test and efficiency of plating (EOP). The zebrafish larvae model was used to test the efficacy of UPM2146 in lysing its host. Based on colony forming unit counts, UPM2146 was able to completely lyse its host at 10 hours onwards. Moreover, we show that the phage is safe to be used in the treatment against K. pneumoniae infections in the zebrafish model.

Matched MeSH terms: Klebsiella Infections/drug therapy; Klebsiella Infections/microbiology*; Klebsiella Infections/therapy; Klebsiella pneumoniae/drug effects; Klebsiella pneumoniae/physiology; Klebsiella pneumoniae/virology*
Fulltext A Good Short-term Outcome in Delayed Decompression of Cauda Equina Syndrome in Klebsiella pneumoniae Spinal Epidural Abscess: A Case Report

Hanifah J, Joehaimey J, Yusof MI

Malays Orthop J, 2017 Jul;11(2):85-88.
PMID: 29021888 MyJurnal DOI: 10.5704/MOJ.1707.018

Spinal epidural abscess is a severe, generally pyogenic, infection of the epidural space of spinal cord or cauda equina. The swelling caused by the abscess leads to compression or vascular disruption of neurological structures that requires urgent surgical decompression to avoid significant permanent disability. We share a rare case of Klebsiella pneumoniae spinal epidural abscess secondary to haematogenous spread of previous lung infection that presented late at our centre with cauda equina syndrome that showed good short-term outcome in delayed decompression. A 50-year old female presented with one-week history of persistent low back pain with progressively worsening bilateral lower limb weakness for seven days and urinary retention associated with saddle anesthesia of 2-day duration. Magnetic resonance imaging with contrast of the lumbo-sacral region showed an intramuscular collection of abscess at left gluteus maximus and left multifidus muscle with a L3-L5 posteriorly placed extradural lesion enhancing peripherally on contrast, suggestive of epidural abscess that compressed the cauda equina. The pus was drained using the posterior lumbar approach. Tissue and pus culture revealed Klebsiella pneumoniae, suggestive of bacterial infection. The patient made immediate improvement of muscle power over bilateral lower limbs postoperative followed by ability to control micturition and defecation the 4th post-operative day. A good short-term outcome in delayed decompression of cauda equine syndrome is extremely rare. Aggressive surgical decompression combined with antibiotic therapy led to good short-term outcome in this patient despite delayed decompression of more than 48 hours.

Matched MeSH terms: Klebsiella pneumoniae
GNAT toxins of bacterial toxin-antitoxin systems: acetylation of charged tRNAs to inhibit translation

Yeo CC

Mol Microbiol, 2018 05;108(4):331-335.
PMID: 29624768 DOI: 10.1111/mmi.13958

GCN5-related N-acetyltransferase (GNAT) is a huge superfamily of proteins spanning the prokaryotic and eukaryotic domains of life. GNAT proteins usually transfer an acetyl group from acetyl-CoA to a wide variety of substrates ranging from aminoglycoside antibiotics to large macromolecules. Type II toxin-antitoxin (TA) modules are typically bicistronic and widespread in bacterial and archael genomes with diverse cellular functions. Recently, a novel family of type II TA toxins was described, which presents a GNAT-fold and functions by acetylating charged tRNA thereby precluding translation. These GNAT toxins are usually associated with a corresponding ribbon-helix-helix-fold (RHH) antitoxin. In this issue, Qian et al. describes a unique GNAT-RHH TA system, designated KacAT, from a multidrug resistant strain of the pathogen, Klebsiella pneumoniae. As most type II TA loci, kacAT is transcriptionally autoregulated with the KacAT complex binding to the operator site via the N-terminus region of KacA to repress kacAT transcription. The crystal structure of the KacT toxin is also presented giving a structural basis for KacT toxicity. These findings expand our knowledge on this newly discovered family of TA toxins and the potential role that they may play in antibiotic tolerance and persistence of bacterial pathogens.

Matched MeSH terms: Klebsiella pneumoniae*
Rare occurrence of polymyxin B-induced hyperpigmentation in a child with ventriculitis

Fitzrol DN, Ang SY, Suhaimi A, Yeap TB

BMJ Case Rep, 2023 Apr 11;16(4).
PMID: 37041040 DOI: 10.1136/bcr-2022-253959

Polymyxin B (PB) is a polypeptide bactericidal antibiotic that is commonly used for extensively drug-resistant (XDR) microorganisms such as Acinetobacter baumanii and Klebsiella pneumoniae It can be administered intravenously or intrathecally. Common side effects are nephrotoxicity, neurotoxicity, pruritus and skin hyperpigmentation (SH). The latter is an uncommon adverse reaction of intravenously administered PB. We report a rare occurrence of PB-induced SH secondary to intrathecal administration of PB in a child with A. baumanii XDR ventriculitis. We describe the management of him and a brief review of PB.

Matched MeSH terms: Klebsiella pneumoniae
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
Conjugal transfer of multiple antibiotic resistance from hospital isolates of Klebsiella to Escherichia coli

Koh CL, Lim ME, Wong YH

Southeast Asian J. Trop. Med. Public Health, 1983 Sep;14(3):336-40.
PMID: 6362015

Six independent isolates of Klebsiella from hospital environmental sources in Malaysia were found to be resistant to at least ampicillin, carbenicillin, cefoperazone, chloramphenicol, gentamicin and tetracycline. On the basis of their antibiograms, they were divided into four antibiogroups. They transferred all or part of their multiple antibiotic resistance traits to E. coli by conjugation. The results suggest that these Klebsiella strains harbour self-transmissible R plasmids. The significance of these findings are discussed.

Matched MeSH terms: Klebsiella/drug effects; Klebsiella/genetics*
Molecular detection of Enterobacteriaceae isolates producing blaOXA-48 and blaOXA-181 genes: A single centre study

Heng PY, Sulong A, Ali UKS, Wong KK

Malays J Pathol, 2019 Aug;41(2):139-148.
PMID: 31427549

INTRODUCTION: OXA-48, a carbapenem-hydrolysing class D β-lactamase, and its variant, OXA-181, are increasingly reported worldwide. This study aimed to describe the prevalence and distribution of OXA-48 and OXA-181 carbapenem-resistant Enterobacteriaceae (CRE) in a tertiary medical centre in Malaysia.
MATERIALS & METHODS: A total of 13,098 Enterobacteriaceae isolates from various clinical samples were sent to our laboratory between January 2011 and December 2012. Of these, 90 demonstrated reduced susceptibility to at least one carbapenem and were included in this study. Only 88 isolates were successfully subcultured on blood agar (BA). Another 2 isolates failed to grow and were excluded. Of the 88, 2 isolates had the same identification number (repetitive isolates); therefore, 1 isolate was excluded from further analyses. Only 87 isolates were subjected to molecular detection of the blaOXA-48 and blaOXA-181 genes by polymerase chain reaction.
RESULTS: Eighty-seven non-repetitive isolates grew following subculture on BA. Of these, 9 (10.34%) were positive for OXA-48 (7 Klebsiella pneumoniae, 2 Escherichia coli). Each isolate originated from different patients. All patients had a history of treatment with at least one cephalosporin and/or carbapenem prior to the isolation of OXA-48 CRE. OXA-181 was detected in one (1.15%) out of the 87 isolates; CONCLUSIONS: The prevalence of OXA-48 and OXA-181 CRE among all Enterobacteriaceae isolates in our institution is 0.069% and 0.008%, respectively. Nevertheless, our findings suggest that OXA-48 and OXA-181 carbapenemases appear to be important and possibly under-recognised causes of carbapenem resistance in Malaysia.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Elucidation of Antimicrobial Activity of Non-Covalently Dispersed Carbon Nanotubes

Saleemi MA, Fouladi MH, Yong PVC, Wong EH

Materials (Basel), 2020 Apr 03;13(7):6-6.
PMID: 32260216 MyJurnal DOI: 10.3390/ma13071676

Microorganisms have begun to develop resistance because of inappropriate and extensive use of antibiotics in the hospital setting. Therefore, it seems to be necessary to find a way to tackle these pathogens by developing new and effective antimicrobial agents. Carbon nanotubes (CNTs) have attracted growing attention because of their remarkable mechanical strength, electrical properties, and chemical and thermal stability for their potential applications in the field of biomedical as therapeutic and diagnostic nanotools. However, the impact of carbon nanotubes on microbial growth has not been fully investigated. The primary purpose of this research study is to investigate the antimicrobial activity of CNTs, particularly double-walled and multi-walled nanotubes on representative pathogenic strains such as Gram-positive bacteria Staphylococcus aureus, Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae, and fungal strain Candida albicans. The dispersion ability of CNT types (double-walled and multi-walled) treated with a surfactant such as sodium dodecyl-benzenesulfonate (SDBS) and their impact on the microbial growth inhibition were also examined. A stock concentration 0.2 mg/mL of both double-walled and multi-walled CNTs was prepared homogenized by dispersing in surfactant solution by using probe sonication. UV-vis absorbance, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) were used for the characterization of CNTs dispersed in the surfactant solution to study the interaction between molecules of surfactant and CNTs. Later, scanning electron microscopy (SEM) was used to investigate how CNTs interact with the microbial cells. The antimicrobial activity was determined by analyzing optical density growth curves and viable cell count. This study revealed that microbial growth inhibited by non-covalently dispersed CNTs was both depend on the concentration and treatment time. In conclusion, the binding of surfactant molecules to the surface of CNTs increases its ability to disperse in aqueous solution. Non-covalent method of CNTs dispersion preserved their structure and increased microbial growth inhibition as a result. Multi-walled CNTs exhibited higher antimicrobial activity compared to double-walled CNTs against selected pathogens.

Matched MeSH terms: Klebsiella pneumoniae
Antibacterial alkaloids from Artabotrys crassifolius Hook.f. & Thomson

Tan KK, Khoo TJ, Rajagopal M, Wiart C

Nat Prod Res, 2015;29(24):2346-9.
PMID: 25738993 DOI: 10.1080/14786419.2015.1013954

Chloroform extract of bark of Artabotrys crassifolius Hook.f. & Thomson exhibited antibacterial activities against both American Type Culture Collection and clinical bacterial strains in vitro with zones of inhibition ranging from 7 to 14 mm. Further analysis of this extract yielded artabotrine, liridine, lysicamine and atherospermidine. Artabotrine displayed a broad array of antibacterial activity mostly against Gram-positive bacteria with minimum inhibitory concentration (MIC) values ranging from 1.25 μg/mL to 5 μg/mL. Of note, artabotrine, liridine and lysicamine are bactericidal against Gram-negative extended-spectrum beta-lactamase-producing Klebsiella with MIC values equal 2.5, 2.5 and 10 μg/mL, respectively, and minimum bactericidal concentrations values equal to 2.5, 5 and 20 μg/mL.

Matched MeSH terms: Klebsiella/drug effects
Fulltext Microbiological quality evaluation of goat milk collected from smallscale dairy farms in Penang Island, Malaysia

Suguna, M., Rajeev Bhat, Wan Nadiah, W. A.

International Food Research Journal, 2012;19(3):1241-1245.
MyJurnal

Microbiological qualities of fresh goat milk collected from two selected, popular dairy farms in Penang Island, Malaysia were evaluated, as a measure of food safety. Milk samples were screened for total plate counts, yeast and mould counts, psychrotrophic counts, Staphylococcus aureus, presumptive Escherichia coli, Coliforms and Klebsiella pneumoniae, which were in the range of (mean values) 4.2- 4.5, 4.2- 4.6, 3.1- 4.3, 2.7- 3.2, < 2- 4.6, 2.2- 4.0 and 4.1- 4.8 log CFU/ml, respectively in the two farms. Milk samples were also screened for the presence of selected foodborne pathogens such as Listeria monocytogenes and Salmonella sp. Results
showed the presence of only Salmonella sp. (at 2.9 log CFU/ml) with the absence of Listeria monocytogenes. The outcome of this study assumes importance as the presence of microbial contaminants amounts indicates poor milk quality, which requires immediate consideration as it can pose serious health risk to consumers.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Revealing the functionality of hypothetical protein KPN00728 from Klebsiella pneumoniae MGH78578: molecular dynamics simulation approaches

Choi SB, Normi YM, Wahab HA

BMC Bioinformatics, 2011;12 Suppl 13:S11.
PMID: 22372825 DOI: 10.1186/1471-2105-12-S13-S11

Previously, the hypothetical protein, KPN00728 from Klebsiella pneumoniae MGH78578 was the Succinate dehydrogenase (SDH) chain C subunit via structural prediction and molecular docking simulation studies. However, due to limitation in docking simulation, an in-depth understanding of how SDH interaction occurs across the transmembrane of mitochondria could not be provided.

Matched MeSH terms: Klebsiella pneumoniae/enzymology*; Klebsiella pneumoniae/metabolism
Fulltext Why hypothetical protein KPN00728 of Klebsiella pneumoniae should be classified as chain C of succinate dehydrogenase?

Choi SB, Normi YM, Wahab HA

Protein J, 2009 Dec;28(9-10):415-27.
PMID: 19859792 DOI: 10.1007/s10930-009-9209-9

Twenty percent of genes that encode for hypothetical proteins from Klebsiella pneumoniae MGH78578 were identified, leading to KPN00728 and KPN00729 after bioinformatics analysis. Both open reading frames showed high sequence homology to Succinate dehydrogenase Chain C (SdhC) and D (SdhD) from Escherichia coli. Recently, KPN00729 was assigned as SdhD. KPN00728 thus remains of particular interest as no annotated genes from the complete genome sequence encode for SdhC. We discovered KPN00728 has a missing region with conserved residues important for ubiquinone (UQ) and heme group binding. Structure and function prediction of KPN00728 coupled with secondary structure analysis and transmembrane topology showed KPN00728 adopts SDH-(subunit C)-like structure. To further probe its functionality, UQ was docked on the built model (consisting KPN00728 and KPN00729) and formation of hydrogen bonds between UQ and Ser27, Arg31 (KPN00728) and Tyr84 (KPN00729) further reinforces and supports that KPN00728 is indeed SDH. This is the first report on the structural and function prediction of KPN00728 of K. pneumoniae MGH78578 as SdhC.

Matched MeSH terms: Klebsiella pneumoniae/enzymology*
Fulltext A secondary mode of action of polymyxins against Gram-negative bacteria involves the inhibition of NADH-quinone oxidoreductase activity

Deris ZZ, Akter J, Sivanesan S, Roberts KD, Thompson PE, Nation RL, et al.

J Antibiot (Tokyo), 2014 Feb;67(2):147-51.
PMID: 24169795 DOI: 10.1038/ja.2013.111

Polymyxin B and colistin were examined for their ability to inhibit the type II NADH-quinone oxidoreductases (NDH-2) of three species of Gram-negative bacteria. Polymyxin B and colistin inhibited the NDH-2 activity in preparations from all of the isolates in a concentration-dependent manner. The mechanism of NDH-2 inhibition by polymyxin B was investigated in detail with Escherichia coli inner membrane preparations and conformed to a mixed inhibition model with respect to ubiquinone-1 and a non-competitive inhibition model with respect to NADH. These suggest that the inhibition of vital respiratory enzymes in the bacterial inner membrane represents one of the secondary modes of action for polymyxins.

Matched MeSH terms: Klebsiella pneumoniae/drug effects; Klebsiella pneumoniae/enzymology
Potent antibacterial activity of halogenated metabolites from Malaysian red algae, Laurencia majuscula (Rhodomelaceae, Ceramiales)

Vairappan CS

Biomol. Eng., 2003 Jul;20(4-6):255-9.
PMID: 12919806

Red algae genus Laurencia (Rhodomelaceae, Ceramiales) are known to produce a wide range of chemically interesting secondary halogenated metabolites. This investigation delves upon extraction, isolation, structural elucidation and antibacterial activity of inherently available secondary metabolites of Laurencia majuscula Harvey collected from two locations in waters of Sabah, Malaysia. Two major halogenated compounds, identified as elatol (1) and iso-obtusol (2) were isolated. Structures of these compounds were determined from their spectroscopic data such as IR, 1H-NMR, 13C-NMR and optical rotation. Antibacterial bioassay against human pathogenic bacteria was conducted using disc diffusion (Kirby-Bauer) method. Elatol (1) inhibited six species of bacteria, with significant antibacterial activities against Staphylococcus epidermis, Klebsiella pneumonia and Salmonella sp. while iso-obtusol (2) exhibited antibacterial activity against four bacterial species with significant activity against K. pneumonia and Salmonella sp. Elatol (1) showed equal and better antibacterial activity compared with tested commercial antibiotics while iso-obtusol (2) only equaled the potency of commercial antibiotics against K. pneumonia and Salmonella sp. Further tests conducted using dilution method showed both compounds as having bacteriostatic mode of action against the tested bacteria.

Matched MeSH terms: Klebsiella/cytology; Klebsiella/drug effects*; Klebsiella/growth & development*
Diversity, antimicrobial and antioxidant activities of culturable bacterial endophyte communities in Aloe vera

Akinsanya MA, Goh JK, Lim SP, Ting AS

FEMS Microbiol Lett, 2015 Dec;362(23):fnv184.
PMID: 26454221 DOI: 10.1093/femsle/fnv184

Twenty-nine culturable bacterial endophytes were isolated from surface-sterilized tissues (root, stem and leaf) of Aloe vera and molecularly characterized to 13 genera: Pseudomonas, Bacillus, Enterobacter, Pantoea, Chryseobacterium, Sphingobacterium, Aeromonas, Providencia, Cedecea, Klebsiella, Cronobacter, Macrococcus and Shigella. The dominant genera include Bacillus (20.7%), Pseudomonas (20.7%) and Enterobacter (13.8%). The crude and ethyl acetate fractions of the metabolites of six isolates, species of Pseudomonas, Bacillus, Chryseobacterium and Shigella, have broad spectral antimicrobial activities against pathogenic Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus cereus, Salmonella Typhimurium, Proteus vulgaris, Klebsiella pneumoniae, Escherichia coli, Streptococcus pyogenes and Candida albicans, with inhibition zones ranging from 6.0 ± 0.57 to 16.6 ± 0.57 mm. In addition, 80% of the bacterial endophytes produced 1,1-diphenyl-2-picrylhydrazyl (DPPH) with scavenging properties of over 75% when their crude metabolites were compared with ascorbic acid (92%). In conclusion, this study revealed for the first time the endophytic bacteria communities from A. vera (Pseudomonas hibiscicola, Macrococcus caseolyticus, Enterobacter ludwigii, Bacillus anthracis) that produce bioactive compounds with high DPPH scavenging properties (75-88%) and (Bacillus tequilensis, Pseudomonas entomophila, Chryseobacterium indologenes, Bacillus aerophilus) that produce bioactive compounds with antimicrobial activities against bacterial pathogens. Hence, we suggest further investigation and characterization of their bioactive compounds.

Matched MeSH terms: Klebsiella; Klebsiella pneumoniae
Characterization of multidrug-resistant and extended-spectrum beta-lactamase-producing Klebsiella pneumoniae strains from Malaysian hospitals

Lim KT, Yeo CC, Md Yasin R, Balan G, Thong KL

J Med Microbiol, 2009 Nov;58(Pt 11):1463-1469.
PMID: 19589908 DOI: 10.1099/jmm.0.011114-0

The emergence of multidrug-resistant (MDR) and extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae poses a serious antibiotic management problem as resistance genes are easily transferred from one organism to another. Fifty-one strains of K. pneumoniae isolated from sporadic cases in various hospitals throughout Malaysia were analysed by antimicrobial susceptibility testing, PCR detection of ESBL-encoding genes and DNA fingerprinting. Although 27 of the 51 K. pneumoniae strains were MDR (i.e. resistant to three or more classes of antibiotics), the majority of the strains (98 %) were sensitive to imipenem. PCR detection using ESBL gene-specific primers showed that 46 of the K. pneumoniae strains harboured bla(SHV), 19 harboured bla(CTX-M), 5 harboured bla(OXA-1) and 4 harboured bla(TEM-1). Class 1 integron-encoded intI1 integrase was detected in 21 of the 51 K. pneumoniae strains and amplification of the integron 5'CS region showed the presence of several known antibiotic resistance gene cassettes of various sizes. Results of conjugation and transformation experiments indicated that some of the ESBL-encoding genes (i.e. bla(SHV), bla(CTX-M) and bla(TEM-1)) were transmissible and were likely plasmid-encoded. DNA fingerprinting using PFGE and PCR-based methods indicated that the 51 K. pneumoniae strains were genetically diverse and heterogeneous.

Matched MeSH terms: Klebsiella pneumoniae/classification; Klebsiella pneumoniae/drug effects*; Klebsiella pneumoniae/genetics; Klebsiella pneumoniae/isolation & purification

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