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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 Stepwise evolution of pandrug-resistance in Klebsiella pneumoniae

Zowawi HM, Forde BM, Alfaresi M, Alzarouni A, Farahat Y, Chong TM, et al.

Sci Rep, 2015;5:15082.
PMID: 26478520 DOI: 10.1038/srep15082

Carbapenem resistant Enterobacteriaceae (CRE) pose an urgent risk to global human health. CRE that are non-susceptible to all commercially available antibiotics threaten to return us to the pre-antibiotic era. Using Single Molecule Real Time (SMRT) sequencing we determined the complete genome of a pandrug-resistant Klebsiella pneumoniae isolate, representing the first complete genome sequence of CRE resistant to all commercially available antibiotics. The precise location of acquired antibiotic resistance elements, including mobile elements carrying genes for the OXA-181 carbapenemase, were defined. Intriguingly, we identified three chromosomal copies of an ISEcp1-bla(OXA-181) mobile element, one of which has disrupted the mgrB regulatory gene, accounting for resistance to colistin. Our findings provide the first description of pandrug-resistant CRE at the genomic level, and reveal the critical role of mobile resistance elements in accelerating the emergence of resistance to other last resort antibiotics.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Molecular Analysis of Antibiotic Resistance Determinants and Plasmids in Malaysian Isolates of Multidrug Resistant Klebsiella pneumoniae

Al-Marzooq F, Mohd Yusof MY, Tay ST

PLoS One, 2015;10(7):e0133654.
PMID: 26203651 DOI: 10.1371/journal.pone.0133654

Infections caused by multidrug resistant Klebsiella pneumoniae have been increasingly reported in many parts of the world. A total of 93 Malaysian multidrug resistant K. pneumoniae isolated from patients attending to University of Malaya Medical Center, Kuala Lumpur, Malaysia from 2010-2012 were investigated for antibiotic resistance determinants including extended-spectrum beta-lactamases (ESBLs), aminoglycoside and trimethoprim/sulfamethoxazole resistance genes and plasmid replicons. CTX-M-15 (91.3%) was the predominant ESBL gene detected in this study. aacC2 gene (67.7%) was the most common gene detected in aminoglycoside-resistant isolates. Trimethoprim/sulfamethoxazole resistance (90.3%) was attributed to the presence of sul1 (53.8%) and dfrA (59.1%) genes in the isolates. Multiple plasmid replicons (1-4) were detected in 95.7% of the isolates. FIIK was the dominant replicon detected together with 13 other types of plasmid replicons. Conjugative plasmids (1-3 plasmids of ~3-100 kb) were obtained from 27 of 43 K. pneumoniae isolates. An ESBL gene (either CTX-M-15, CTX-M-3 or SHV-12) was detected from each transconjugant. Co-detection with at least one of other antibiotic resistance determinants [sul1, dfrA, aacC2, aac(6')-Ib, aac(6')-Ib-cr and qnrB] was noted in most conjugative plasmids. The transconjugants were resistant to multiple antibiotics including β-lactams, gentamicin and cotrimoxazole, but not ciprofloxacin. This is the first study describing the characterization of plasmids circulating in Malaysian multidrug resistant K. pneumoniae isolates. The results of this study suggest the diffusion of highly diverse plasmids with multiple antibiotic resistance determinants among the Malaysian isolates. Effective infection control measures and antibiotic stewardship programs should be adopted to limit the spread of the multidrug resistant bacteria in healthcare settings.

Matched MeSH terms: Klebsiella pneumoniae/drug effects*; Klebsiella pneumoniae/enzymology; Klebsiella pneumoniae/genetics
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
Fulltext Data on whole-genome sequencing of extended-spectrum beta-lactamases producing Enterobacteriaceae isolates from Malaysia

Gan HM, Eng WWH, Dhanoa A

Data Brief, 2019 Aug;25:104257.
PMID: 31384648 DOI: 10.1016/j.dib.2019.104257

We report the whole genome sequencing data and de novo genome assemblies for eight extended-spectrum beta-lactamases (ESBL) producing Enterobacteriaceae isolates from Malaysia consisting of four Klebsiella pneumoniae, two Enterobacter harmaechei, one Citrobacter freundii and one Escherichia coli. We identified at least one ESBL gene in each genome, with blaCTX-M-15 being the most prevalent ESBL gene in the current genomic sampling.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Effects of phenylpyruvate feeding with polymyxin B in Klebsiella pneumoniae

Wong, A. S-L., Nusaibah Abdul Rahim

Malaysian Journal of Medicine and Health Sciences, 2019;15(102):5-5.
MyJurnal

Introduction: Polymyxin B (PMB) is one of the remaining antibiotics that is effective against multidrug resistant (MDR) Gram-negative bacteria. However, PMB monotherapy is not able to achieve sustained killing hence, combination with other antibiotics are usually employed. Besides antibiotics, studies are now moving towards non-antibiotic alternatives such as metabolite feeding against MDR pathogens. This study aimed to investigate the susceptibility
and bacterial killing of PMB in combination with metabolite phenylpyruvate against Klebsiella pneumoniae isolates. Methods: Broth microdilution was used to determine PMB minimum inhibitory concentration (MIC) alone and with phenylpyruvate against two Klebsiella pneumoniae isolates. Time kill studies were performed over 24 h (initial inoculum: ~106 CFU/mL), using PMB 2 mg/L and phenylpyruvate 2 mmol/L, alone and in combination, against the
PMB-resistant isolate. Microbiological responses were examined using the log-change method. Results: The MIC of PMB was reduced by phenylpyruvate in both isolates. In the time kill studies, during the first hour, PMB monotherapy demonstrated the highest bacterial killing activity even compared to the combination. Phenylpyruvate monotherapy showed negligible activity against K. pneumoniae. A significant reduction in bacterial burden was seen at 1 h following PMB monotherapy and combination therapy but an equally rapid regrowth was seen at 4 h. Notably at 24 h, the regrowth following combination therapy was >1-log10 CFU/mL less than PMB monotherapy. Conclusion: Our results suggest that phenylpyruvate increased PMB susceptibility in K. pneumoniae and may minimise the emergence of resistance to PMB. Future studies investigating phenylpyruvate at higher concentrations against more isolates are
warranted.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Seroepidemiology of Klebsiella pneumoniae colonizing the intestinal tract of healthy Chinese and overseas Chinese adults in Asian countries

Lin YT, Siu LK, Lin JC, Chen TL, Tseng CP, Yeh KM, et al.

BMC Microbiol, 2012;12:13.
PMID: 22260182 DOI: 10.1186/1471-2180-12-13

Capsular serotypes K1 and K2 of Klebsiella pneumoniae are thought to the major virulence determinants responsible for liver abscess. The intestine is one of the major reservoirs of K. pneumoniae, and epidemiological studies have suggested that the majority of K. pneumoniae infections are preceded by colonization of the gastrointestinal tract. The possibility of fecal-oral transmission in liver abscess has been raised on the basis of molecular typing of isolates. Data on the serotype distribution of K. pneumoniae in stool samples from healthy individuals has not been previously reported. This study investigated the seroepidemiology of K. pneumoniae isolates from the intestinal tract of healthy Chinese in Asian countries. Stool specimens from healthy adult Chinese residents of Taiwan, Japan, Hong Kong, China, Thailand, Malaysia, Singapore, and Vietnam were collected from August 2004 to August 2010 for analysis.

Matched MeSH terms: Klebsiella pneumoniae/classification*; Klebsiella pneumoniae/drug effects; Klebsiella pneumoniae/isolation & purification
Characterization of the first isolate of Klebsiella pneumoniae carrying New Delhi metallo-β-lactamase and other extended spectrum β-lactamase genes from Malaysia

Ahmad N, Hashim R, Shukor S, Mohd Khalid KN, Shamsudin F, Hussin H

J Med Microbiol, 2013 May;62(Pt 5):804-806.
PMID: 23449878 DOI: 10.1099/jmm.0.050781-0
Matched MeSH terms: Klebsiella pneumoniae/drug effects*; Klebsiella pneumoniae/enzymology*; Klebsiella pneumoniae/genetics
Fulltext Detection of Klebsiella pneumoniae in raw vegetables using Most Probable Number-Polymerase Chain Reaction (MPN-PCR)

Puspanadan, S., Afsah-Hejri, L., Loo, Y.Y., Nillian, E., Kuan, C.H., Goh, S.G., et al.

International Food Research Journal, 2012;19(4):1757-1762.
MyJurnal

Klebsiella pneumoniae (K. pneumoniae) is one of the most important members of Klebsiella genus in Enterobacteriacae family, which is responsible for pneumonia (the destructive lung inflammation disease). Vegetables are known as source of contamination with K. pneumonia. Raw vegetables are usually consumed in salads and other dishes. The aim of this study was to investigate the occurrence of K. pneumoniae in raw vegetables marketed in Malaysia. Two hundred commonly used salad vegetables (lettuces, parsley, cucumber, tomato and carrot) from hypermarkets and wet markets were investigated for presence of K. pneumoniae using Most Probable Number-Polymerase Chain Reaction (MPN-PCR). K. pneumoniae was found to be significantly more frequent (100%) and (82.5%) in lettuce and cucumbers, respectively. K. pneumoniae contamination was lowest in carrot samples (30%). All samples were contaminated with K. pneumoniae ranging from

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Characterization of extended-spectrum ß -lactamases (ESBLs) producers in Klebsiella pneumoniae by genotypic and phenotypic method

Puspanadan, S., Afsah-Hejri, L., Rukayadi, Y., Loo, Y.Y., Nillian, E., Kuan, C.H., et al.

International Food Research Journal, 2013;20(3):1479-1483.
MyJurnal

This study aims to determine the presence of extended-spectrum (ESBL) in Klebsiella pneumoniae isolated from raw vegetables by genotypic and phenotypic method. Fifty-three K. pneumoniae isolates that were obtained by plating method were confirmed by PCR. Isolates obtained were screened for their resistance to selected antibiotics. Phenotypic tests for ESBL detection is basically to confirm production of ESBL, in this study two types of antibiotics used which were amoxycillin/clavulanic Acid (AMC, 30 µg) and ceftazidime (CAZ, 30 µg), The resistance were 5/53 (9.4%) and 1/53 (1.9%), respectively. However, it was interesting to observe that none of the K. pneumoniae isolates demonstrated the presence of any of the bla genes by using genotypic method except blaTEM gene has been detected in two isolates out of 53 isolates of K. pneumoniae in this research.

Matched MeSH terms: Klebsiella pneumoniae
High burden of Carbapenem-resistant Enterobacteriaceae (CRE) fecal carriage at a teaching hospital: cost-effectiveness of screening in low-resource setting

Zaidah AR, Mohammad NI, Suraiya S, Harun A

Antimicrob Resist Infect Control, 2017;6:42.
PMID: 28473912 DOI: 10.1186/s13756-017-0200-5

BACKGROUND: Infections by multidrug-resistant gram-negative bacteria (MDR-GNB) have been continuously growing and pose challenge to health institution globally. Carbapenem-resistant Enterobacteriacea (CRE) was identified as one of the MDR-GNB which has limited treatment options and higher mortality compared to those of sensitive strains. We report an increased burden of CRE fecal carriage at a hospital in the North-eastern region of Malaysia.
METHODS: A retrospective descriptive study from August 2013 to December 2015 was conducted in the Medical Microbiology & Parasitology laboratory of Hospital Universiti Sains Malaysia, which is a tertiary teaching hospital with more than 700 beds. This hospital treats patients with various medical and surgical conditions. Suspected CRE from any clinical specimens received by the laboratory was identified and confirmed using standard protocols. Polymerase chain reaction (PCR) assay was performed to determine the genotype.
RESULTS: Altogether, 8306 Enterobacteriaceae was isolated from various clinical specimens during the study period and 477/8306 (5.74%) were CRE. Majority of the isolated CRE were Klebsiella [408/477, (85.5%)], of which Klebsiella pneumoniae was the predominant species, 388/408 (95%). CRE were mainly isolated from rectal swab (screening), 235/477 (49.3%); urine, 76/477 (15.9%); blood, 46/477 (9.6%) and about 7.1% from tracheal aspirate. One hundred and thirty-six isolates were subjected to genotype determination and., 112/136 (82.4%) showed positive detection of New Delhi metallo-β-lactamase 1 (NDM-1) gene (blaNDM1).
CONCLUSION: The study noted a high numbers of CRE isolated especially from rectal swabs. Active screening results in significant cost pressures and therefore should be revisited and revised, especially in low resource settings.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Klebsiella pneumoniae sacroiliac septic arthritis: First case report

Chee YC, Lim CH

IDCases, 2018;14:e00459.
PMID: 30386726 DOI: 10.1016/j.idcr.2018.e00459

Infective sacroiliitis is a rare disease with misleading clinical signs that often delay diagnosis. We report a case of pyogenic sacroiliac joint septic arthritis caused by Klebsiella pneumoniae that has not been reported in the literature highlighting it as one of the important etiologies of infective sacroiliitis especially among diabetics.

Matched MeSH terms: Klebsiella pneumoniae
A Rare Case of a Distal Humerus Pathological Fracture from Klebsiella Pneumoniae Osteomyelitis: A Case Report

Chan MF, Kwek E

Malays Orthop J, 2020 Mar;14(1):81-83.
PMID: 32296487 DOI: 10.5704/MOJ.2003.013

Klebsiella pneumoniae is one of the leading causative organisms in pyogenic liver disease. It can cause disseminated infections, but rarely to bone, and rarely in healthy hosts. We report an unusual case of a distal humerus fracture from osteomyelitis secondary to dissemination in a non-immuno-compromised patient. The patient was surgically managed with external fixation and insertion of anti-biotic beads, in conjunction with medical therapy via culture direct antibiotics. This report highlights the diagnostic approach and treatment options for these atypical cases.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext A retrospective study on molecular epidemiology trends of carbapenem resistant Enterobacteriaceae in a teaching hospital in Malaysia

Kong ZX, N Karunakaran R, Abdul Jabar K, Ponnampalavanar S, Chong CW, Teh CSJ

PeerJ, 2022;10:e12830.
PMID: 35223201 DOI: 10.7717/peerj.12830

BACKGROUND: Carbapenem resistant Enterobacteriaceae (CRE) has rapidly disseminated worldwide and has become a global threat to the healthcare system due to its resistance towards "last line" antibiotics. This study aimed to investigate the prevalence of CRE and the resistance mechanism as well as the risk factors associated with in-hospital mortality.
METHODS: A total of 168 CRE strains isolated from a tertiary teaching hospital from 2014-2015 were included in this study. The presence of carbapenemase genes and minimum inhibitory concentration of imipenem, meropenem and colistin were investigated. All carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) strains were characterised by PFGE. The risk factors of patients infected by CRE associated with in-hospital mortality were determined statistically.
RESULTS: The predominant CRE species isolated was K. pneumoniae. The carbapenemases detected were blaOXA-48, blaOXA-232, blaVIM and blaNDM of which blaOXA-48 was the predominant carbapenemase detected among 168 CRE strains. A total of 40 CRE strains harboured two different carbapenemase genes. A total of seven clusters and 48 pulsotypes were identified among 140 CRKp strains. A predominant pulsotype responsible for the transmission from 2014 to 2015 was identified. Univariate statistical analysis identified that the period between CRE isolation and start of appropriate therapy of more than 3 days was statistically associated with in-hospital mortality.

Matched MeSH terms: Klebsiella pneumoniae
Fulltext Bacteriology of diabetic foot lesions

Yoga R, Khairul A, Sunita K, Suresh C

Med J Malaysia, 2006 Feb;61 Suppl A:14-6.
PMID: 17042222

Infection plays a pivotal role in enhancing a diabetic foot at risk toward amputation. Effective antibiotic therapy against the offending pathogens is an important component of treatment of diabetic foot infections. Recognition of the pathogen is always difficult as the representative deep tissue sample for culture is surrounded by ulcer surface harbouring colonies of organisms frequently labelled as skin commensals. The emergent of resistant strains represents a compounding problem standing against efforts to prevent amputation. This study was undertaken to identify the pathogens associated with diabetic foot infection in terms of their frequency and sensitivity against certain commonly used antibiotics. Forty-four consecutive patients with open diabetic foot infections had wound swab taken for culture and sensitivity testing. Cultures positive were observed in 89% of the cases with Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeroginosa encountered in 20%, 14% and 14% of cases respectively. Mixed growths were isolated in 6% of cultures. All Staphylcoccus aureus isolates were resistant to Penicillin but 80% were sensitive to Erythromycin and Co-trimoxazole. Klebsiella pneumoniae isolates were sensitive to Methicillin and Gentamycin in 80% and 60% of cases respectively, and resistant to Ampicillin and Ceftazidime in 83% and 50% respectively. All Pseudomonas aeroginosa isolates were sensitive to Amikacin and Ciprofloxacin but 50% were resistant to Gentamycin. There was no single antibiotic possessing good coverage for all common organisms isolated from diabetic foot lesions. Staphylococcus aureus remains the predominant cause of diabetic foot infections followed by Klebsiela pneumonia and Pseudomonas aeroginosa. Most infections are monomicrobial. The emergence of multiresistant organisms is a worrying feature in diabetic foot infections.

Matched MeSH terms: Klebsiella pneumoniae/isolation & purification*
Fulltext In vitro activity of sulperazon against recent isolates of ceftazidime-resistant bacteria

Lim VKE, Halijah MY

Med J Malaysia, 2001 Sep;56(3):365-9.
PMID: 11732084

The in vitro activity of sulperazon (cefoperazone/sulbactam) was tested against 94 ceftazidime-resistant strains of bacteria isolated from mostly seriously ill patients in critical care units. Acinetobacter baumanii, Pseudomonas aeruginosa and Klebsiella pneumoniae made up 80% of the pathogens studied; 90% of the Klebsiella strains were producers of extended-spectrum beta-lactamases (ESBL). The MIC90 of sulperazon for Klebsiella was 12 mg/l (range 1.5-16 mg/l), indicating that this drug may be a useful alternative for the treatment of ceftazidime-resistant, ESBL-producing Klebsiella.

Matched MeSH terms: Klebsiella pneumoniae/drug effects
Comparison of three different methods for the presumptive detection of ESBL production in ceftazidime-resistant strains of Klebsiella pneumoniae

Palasubramaniam S, Parasakthi N

Malays J Pathol, 2001 Dec;23(2):73-8.
PMID: 12166595

Twenty-eight (28) strains of ceftazidime-resistant Klebsiella pneumoniae were isolated from blood cultures of in-patients from University Hospital, Kuala Lumpur between March 1995 and August 1996. Three methods were used to detect the production of ESBL enzymes by these strains. These three methods include the double-disc synergy test (DDST), inhibitor-potentiated disc-diffusion test (IPDD) and the E-test ESBL method. All strains could be identified as ESBL producers using the DDST method by a minimum of two beta-lactams and these included either a combination of ceftazidime and ceftriaxone with clavulanate respectively or cefotaxime and aztreonam with clavulanate respectively. Similarly using a combination of either cefotaxime and ceftriaxone with clavulanate or ceftriaxone and aztreonam with clavulanate respectively would have detected all strains as ESBL producers. The IPDD method could also detect for ESBL activity based on combinations of beta-lactam antibiotics with clavulanate respectively. All combinations of beta-lactam antibiotics could detect for ESBL activity in all the strains except a combination of either ceftazidime and aztreonam or cefotaxime and ceftriaxone with clavulanate respectively. The E-Test method using ceftazidime alone and in combination with clavulanate was found to be the most effective method in the presumptive identification of ESBL activity in all the strains.

Matched MeSH terms: Klebsiella pneumoniae/physiology*
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*
The Role of Peganum harmala Ethanolic Extract and Type II Toxin Antitoxin System in Biofilm Formation

Valizadeh N, Valian F, Sadeghifard N, Karami S, Pakzad I, Kazemian H, et al.

Drug Res (Stuttg), 2017 Jul;67(7):385-387.
PMID: 28320039 DOI: 10.1055/s-0043-102060

Toxin antitoxin system is a regulatory system that antitoxin inhibits the toxin. We aimed to determine the role of TA loci in biofilm formation in K. pneumoniae clinical and environmental isolates; also inhibition of biofilm formation by Peganum harmala. So, 40 K. pneumoniae clinical and environmental isolates were subjected for PCR to determine the frequency of mazEF, relEB, and mqsRA TA loci. Biofilm formation assay subjected for all isolates. Then, P. harmala was tested against positive biofilm formation strains. Our results demonstrated that relBE TA loci were dominant TA loci; whereas mqsRA TA loci were negative in all isolates. The most environmental isolates showed weak and no biofilm formation while strong and moderate biofilm formation observed in clinical isolates. Biofilm formations by K. pneumoniae in 9 ug/ml concentration were inhibited by P. harmala. In vivo study suggested to be performed to introduce Peganum harmala as anti-biofilm formation in K. pneumoniae.

Matched MeSH terms: Klebsiella pneumoniae/metabolism*
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: Klebsiella pneumoniae/drug effects*

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