scholarly journals Rhenium and yttrium ions as antimicrobial agents against multidrug resistant Klebsiella pneumoniae and Acinetobacter baumannii biofilms

2019 ◽  
Author(s):  
A.J. Slate ◽  
L. Shalamanova ◽  
I.D. Akhidime ◽  
K.A. Whitehead
Keyword(s):  
Klebsiella Pneumoniae ◽  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Multidrug Resistant

scholarly journals Isolation and Characterization of Novel Phages Targeting Pathogenic Klebsiella pneumoniae

2021 ◽  
Vol 11 ◽  
Author(s):  
Na Li ◽  
Yigang Zeng ◽  
Rong Bao ◽  
Tongyu Zhu ◽  
Demeng Tan ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
S1 Nuclease ◽  
Isolation And Characterization ◽  
Comprehensive Knowledge ◽  
Future Challenges ◽  
Lactamase Gene

Klebsiella pneumoniae is a dominant cause of community-acquired and nosocomial infections, specifically among immunocompromised individuals. The increasing occurrence of multidrug-resistant (MDR) isolates has significantly impacted the effectiveness of antimicrobial agents. As antibiotic resistance is becoming increasingly prevalent worldwide, the use of bacteriophages to treat pathogenic bacterial infections has recently gained attention. Elucidating the details of phage-bacteria interactions will provide insights into phage biology and the better development of phage therapy. In this study, a total of 22 K. pneumoniae isolates were assessed for their genetic and phenotypic relatedness by multi-locus sequence typing (MLST), endonuclease S1 nuclease pulsed-field gel electrophoresis (S1-PFGE), and in vitro antibiotic susceptibility testing. In addition, the beta-lactamase gene (blaKPC) was characterized to determine the spread and outbreak of K. pneumoniae carbapenemase (KPC)-producing enterobacterial pathogens. Using these ST11 carbapenem-resistant K. pneumoniae isolates, three phages (NL_ZS_1, NL_ZS_2, and NL_ZS_3) from the family of Podoviridae were isolated and characterized to evaluate the application of lytic phages against the MDR K. pneumoniae isolates. In vitro inhibition assays with three phages and K. pneumoniae strain ZS15 demonstrated the strong lytic potential of the phages, however, followed by the rapid growth of phage-resistant and phage-sensitive mutants, suggesting several anti-phage mechanisms had developed in the host populations. Together, this data adds more comprehensive knowledge to known phage biology and further emphasizes their complexity and future challenges to overcome prior to using phages for controlling this important MDR bacterium.

scholarly journals Evaluation of Moringa Peregrina (Forsk) Fiori, Leaf and Seed Extract Against Multidrug Resistant Strains of Bacteria and Fungus of Clinical Origin

2021 ◽  
Vol 3 (1) ◽  
pp. 20-26
Author(s):  
Suliman Mansour Albalawi ◽  
Abdulrahman K. Al-Asmari ◽  
Syed Rafatullah ◽  
Maysa Mahfoud
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Growth Inhibition ◽  
Acinetobacter Baumannii ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Colorimetric Assay ◽  
Multidrug Resistant ◽  
Klebsiella Pneumonia ◽  
Isolation And Purification ◽  
Moringa Peregrina

  The emergence of antibiotic resistant microorganism strains has become a critical concern in the treatment of infectious diseases and makes the search of an alternative therapy a must. The study was designed to evaluate the in vitro antimicrobial activities of the Moringa peregrina (MP) leave (MPL) and seed (MPS) extracts. Antimicrobial assays were performed using a microplate growth inhibition assay against 11 multidrug-resistant (MDR) strains. Following qualitative analysis, dose-response assays were performed using the MTT colorimetric assay. The results showed a strong correlation between the MPL and MPS extract concentration and growth inhibition (P<0.001). MP extract revealed a remarkable antimicrobial effect and inhibited the growth and survival of MDR pathogens which include Escherichia coli; Pseudomonas aeruginosa; Klebsiella pneumonia; Acinetobacter baumannii; Staphylococcus aureus between (88.6-94.7 %) and between (62.3- 88.7%) against Candida Kefyer; Candida parapsilosis; Candida albicans; Candida glabrata; Aspergillus flavus and Fusarium oxysporum. MIC50 ranging from ≤6.25 to 25 mg/mL. Acinetobacter baumannii and Pseudomonas aeruginosa were the most susceptible to MP extracts (MIC50 < 6.25 mg/mL). These results support the use of MP in Arab traditional medicine as natural antimicrobial agents. Additionally, the use of such naturally occurring adjuvant derived from medicinal plants can be used as an adjuvant with synthetic antibiotics to combat bacterial resistance and to enhance the antibacterial potential. Further studies are recommended on isolation and purification of novel antimicrobial molecules to treat the infections caused by microbes.  

scholarly journals Functional Characterization of AbaQ, a Novel Efflux Pump Mediating Quinolone Resistance inAcinetobacter baumannii

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
María Pérez-Varela ◽  
Jordi Corral ◽  
Jesús Aranda ◽  
Jordi Barbé
Keyword(s):  
Acinetobacter Baumannii ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Functional Characterization ◽  
Multidrug Resistant ◽  
Quinolone Resistance ◽  
Nosocomial Pathogen ◽  
Content Type ◽  
Mfs Transporter

ABSTRACTAcinetobacter baumanniihas emerged as an important multidrug-resistant nosocomial pathogen. In previous work, we identified a putative MFS transporter, AU097_RS17040, involved in the pathogenicity ofA. baumannii(M. Pérez-Varela, J. Corral, J. A. Vallejo, S. Rumbo-Feal, G. Bou, J. Aranda, and J. Barbé, Infect Immun 85:e00327-17, 2017,https://doi.org/10.1128/IAI.00327-17). In this study, we analyzed the susceptibility to diverse antimicrobial agents ofA. baumanniicells defective in this transporter, referred to as AbaQ. Our results showed that AbaQ is mainly involved in the extrusion of quinolone-type drugs inA. baumannii.

scholarly journals Homeostasis of Glutathione Is Associated with Polyamine-Mediated β-Lactam Susceptibility in Acinetobacter baumannii ATCC 19606

2013 ◽  
Vol 57 (11) ◽  
pp. 5457-5461 ◽  
Author(s):  
Dong H. Kwon ◽  
Saboor Hekmaty ◽  
Gomattie Seecoomar
Keyword(s):  
Acinetobacter Baumannii ◽  
Redox State ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Transport Systems ◽  
Toxic Substances ◽  
Cellular Redox ◽  
Content Type ◽  
Intracellular Glutathione ◽  
Cellular Redox State

ABSTRACTGlutathione is a tripeptide (l-γ-glutamyl–l-cysteinyl–glycine) thiol compound existing in many bacteria and maintains a proper cellular redox state, thus protecting cells against toxic substances such as reactive oxygen species. Polyamines (spermine and spermidine) are low-molecular-weight aliphatic polycations ubiquitously presenting in all living cells and modulate many cellular functions. We previously reported that exogenous polyamines significantly enhanced β-lactam susceptibility of β-lactam-associated multidrug-resistantAcinetobacter baumannii. In this study, three genes differentially associated with the polyamine effects on β-lactam susceptibility were identified by transposon mutagenesis ofA. baumanniiATCC 19606. All three genes encoded components of membrane transport systems. Inactivation of one of the genes encoding a putative glutathione transport ATP-binding protein increased the accumulation of intracellular glutathione (∼150 to ∼200%) and significantly decreased the polyamine effects on β-lactam susceptibility inA. baumanniiATCC 19606. When the cells were grown with polyamines, the levels of intracellular glutathione inA. baumanniiATCC 19606 significantly decreased from ∼0.5 to ∼0.2 nmol, while the levels of extracellular glutathione were correspondingly increased. However, the levels of total glutathione (intra- plus extracellular) were unchanged when the cells were grown with or without polyamines. Overall, these results suggest that exogenous polyamines induce glutathione export, resulting in decreased levels of intracellular glutathione, which may produce an improper cellular redox state that is associated with the polyamine-mediated β-lactam susceptibility ofA. baumannii. This finding may provide a clue for development of new antimicrobial agents and/or novel strategies to treat multidrug-resistantA. baumannii.

scholarly journals Comparison of Automated and Manual Methods for Antimicrobial Susceptibility Testing

2020 ◽  
pp. 43-48
Author(s):  
Asifa Bhat ◽  
Dekyong Angmo ◽  
Shaista Nazir
Keyword(s):  
Klebsiella Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Error Rate ◽  
Antimicrobial Agents ◽  
Reference Method ◽  
Multidrug Resistant ◽  
Dilution Method ◽  
Automated Method ◽  
Broth Microdilution Method ◽  
Vitek 2

Background: Carbapenems are considered the broadest-spectrum β-lactam agents and are often required for treatment of severe hospital-acquired infections caused by multidrug-resistant Gram-negative organisms. Minimum inhibitory concentrations (MICs) are important in diagnostic laboratories to confirm resistance of microorganisms to an antimicrobial agent and also to monitor the activity of new antimicrobial agents. Aims and Objectives: To compare the MIC obtained by Broth Microdilution method (BMD) with that of Vitek-2(automated method) for recovered isolates of Klebsiella pneumoniae. Materials and Methods: Prospective study conducted over a period of one year. It included all isolates of Klebsiella pneumoniae recovered from blood culture of the patients. The identification and antimicrobial susceptibility was done on Vitek-2.These Isolates were subjected to Microbroth dilution method for MIC determination. Results: Out of the 55 meropenem resistant  isolates by vitek-2, 20(36.3%) had MIC of ≥256 µg/ml followed by 18(32.7%) isolates with a MIC of 128 µg/ml, followed by 11(20%) isolates with MIC of 64 µg/ml and 6(10.9%) isolates with MIC of 32 µg/ml. Also among 15 meropenem sensitive isolates by Vitek-2, 13(86.7%) had MIC of ≤0.5 µg/ml, followed by two (13.3%) isolates with MIC of 2 µg/ml. Results obtained by vitek 2 were compared with those from BMD(the reference method), which showed a 13.3% minor error rate and no major or very major error rate. Conclusion: Overall, the Vitek 2 performance was comparable to that of BMD for testing a limited number of Klebsiella pneumoniae isolates.

Prevalence and molecular mechanisms of colistin resistance in Acinetobacter baumannii clinical isolates in Tehran, Iran

2021 ◽  
Author(s):  
Amin Khoshbayan ◽  
Aref Shariati ◽  
Samane Shahmoradi ◽  
Zohre Baseri ◽  
Haniyeh Mozafari ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Molecular Mechanisms ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Clinical Samples ◽  
Gram Negative Bacteria ◽  
Colistin Resistance ◽  
Two Component System ◽  
Reverse Transcription Pcr ◽  
Polymerase Chain

AbstractColistin is one of the last remaining active antibiotics against multidrug resistant Gram-negative bacteria. However, several recent studies reported colistin-resistant (ColR) Acinetobacter baumannii from different countries. In the current study, we investigated molecular mechanisms involved in colistin resistance in A. baumannii isolates from different clinical samples.A total of 110 clinical A. baumannii isolates were collected from two hospitals in Tehran. Minimum inhibitory concentrations (MICs) were determined by broth microdilution according to the Clinical and Laboratory Standards Institute. For the ColR isolates, mutation was detected in pmrA, pmrB, lpxA, lpxC, and lpxD genes using the polymerase chain reaction (PCR) and sequencing. Moreover, the relative expression of the pmrC gene was calculated using quantitative reverse transcription PCR. Three colistin resistant isolates were identified with MIC between 8 and 16 μg/mL and were resistant to all the tested antimicrobial agents. All the three isolates had a mutation in the pmrB, pmrA, lpxA, lpxD, and lpxC genes. Moreover, the overexpression of pmrC gene was observed in all isolates. Our results showed that the upregulation of the PmrAB two component system was the primary mechanism linked to colistin resistance among the studied colistin resistant A. baumannii isolates.

Klebsiella pneumoniae in Germany: An overview on spatiotemporal distribution and resistance development in humans

2021 ◽  
Vol 1 (1) ◽  
pp. 16-25
Keyword(s):  
Klebsiella Pneumoniae ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Resistance Development ◽  
Federal States ◽  
Treatment Regimens ◽  
The Past ◽  
Resistance Patterns ◽  
Chronological Sequence ◽  
Rapid Dissemination

The emerging of multidrug-resistant Klebsiella pneumoniae (K. pneumoniae) is increasing worldwide. Rapid dissemination and increase of its incidence in Germany are observed and becoming a significant challenge for clinical laboratories and physicians. The current review highlights its chronological sequence of appearance and resistance development in humans in the past two decades in Germany. Emerging resistance problems of K. pneumoniae to the vast majority of available antimicrobial agents, including carbapenems and those of the ß-lactam group, were observed since the end of the last century and strains carrying diverse resistance patterns have emerged in most federal states of Germany. Still, several aspects of resistance development and pathogenesis are not fully understood. To date, hypervirulent K. pneumoniae (hvKp) isolates have been rarely isolated from German patients. The most frequent resistance genes identified are blaOXA-48, blaCTX-M-15, blaKPC-2, blaOXA-9, blaSHV-11, blaSHV-5 blaCTX-M-3, blaCTX-M-14, blaVIM-1 and the plasmid-encoded quinolone resistance (PMQR) gene. One Health genomic surveillance of K. pneumoniae strains from different reservoirs is required. This would help to understand in great detail the mechanisms leading to resistance development, spread and transmission, and developing alternative treatment regimens

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