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El Megdar S, Fayzi L, Elkheloui R, Laktib A, Bourouache M, El Boulani A, Abou Oualid H, Cherifi K, Msanda F, Hassi M, Mimouni R, Hamadi F. Biological Synthesis of Silver Nanoparticles from Lavandula mairei Humbert: Antibacterial and Antioxidant Activities. Curr Microbiol 2024; 81:151. [PMID: 38647541 DOI: 10.1007/s00284-024-03670-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 03/18/2024] [Indexed: 04/25/2024]
Abstract
Hospital-acquired infections involving carbapenem-resistant Acinetobacter baumannii (A. baumannii) and extended spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae pose significant challenges in the intensive care units. The lack of novel antimicrobial drugs amplifies the urgency to explore innovative management strategies. Nanotechnology, with its ability to generate nanoparticles possessing specific properties beneficial in drug delivery and nanomedicine, stands as a pivotal research domain. The objective of this study was to synthesize, for the first time, biologically silver nanoparticles (Ag-NPs) from Lavandula mairei Humbert (L. mairei) plant. The biosynthesized Ag-NPs were characterized by UV-visible spectral analysis, X-Ray diffraction Analysis, Fourier transform infrared spectroscopy analysis, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy. Subsequently, the antibacterial and antioxidant activities of Ag-NPs were assessed using the micro-dilution method, DPPH test and FRAP assay, respectively. The green-synthesized Ag-NPs exhibited high antibacterial activity against ESBL-producing multidrug-resistant (MDR) strains and against carbapenem-resistant and non-carbapenem-resistant strains of A. baumannii, as well as a very interesting antioxidant activity. The present study suggests that these results hold very promising for the potential application of biologically synthesized Ag-NPs from L. mairei (Ag-LM-NPs) in the invention of novel antibacterial and antioxidant agents.
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Affiliation(s)
- Soufiane El Megdar
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Lahbib Fayzi
- Laboratory of Biotechnologies and Valorization of Natural Resources, Biology Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Raja Elkheloui
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Asma Laktib
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Mohamed Bourouache
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Abdellah El Boulani
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Hicham Abou Oualid
- Green Energy Park, Institut de Recherche en Energie Solaire Et Energies Nouvelles (IRESEN), Benguerir, Morocco
| | - Khalil Cherifi
- Laboratory of Biotechnologies and Valorization of Natural Resources, Biology Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Fouad Msanda
- Laboratory of Biotechnologies and Valorization of Natural Resources, Biology Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Mohamed Hassi
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Rachida Mimouni
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco
| | - Fatima Hamadi
- Laboratory of Microbial Biotechnology and Plants Protection. Biology, Department. Sciences Faculty, Ibn Zohr University, Agadir, Morocco.
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Sarkar S, Kumari A, Tiwari M, Tiwari V. Interaction and simulation studies suggest the possible molecular targets of intrinsically disordered amyloidogenic antimicrobial peptides in Acinetobacter baumannii. J Biomol Struct Dyn 2024; 42:2747-2764. [PMID: 37144752 DOI: 10.1080/07391102.2023.2208219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 04/20/2023] [Indexed: 05/06/2023]
Abstract
Acinetobacter baumannii is one of the causing agents of nosocomial infections. A wide range of antibiotics fails to work against these pathogens. Hence, there is an urgent requirement to develop other therapeutics to solve this problem. Antimicrobial peptides (AMPs) are a diverse group of naturally occurring peptides that have the ability to kill diverse groups of microorganisms. The major challenge of using AMPs as therapeutics is their unstable nature and the fact that most of their molecular targets are still unknown. In this study, we have selected intrinsically disordered and amyloidogenic AMPs, showing activity against A. baumannii, that is, Bactenecin, Cath BF, Citropin 1.1, DP7, NA-CATH, Tachyplesin, and WAM-1. To identify the probable target of these AMPs in A. baumannii, calculation of docking score, binding energy, dissociation constant, and molecular dynamics analysis was performed with selected seventeen possible molecular targets. The result showed that the most probable molecular targets of most of the intrinsically disordered amyloidogenic AMPs were UDP-N-acetylenol-pyruvoyl-glucosamine reductase (MurB), followed by 33-36 kDa outer membrane protein (Omp 33-36), UDP-N-acetylmuramoyl-l-alanyl-d-glutamate-2,6-diaminopimelate ligase (MurE), and porin Subfamily Protein (PorinSubF). Further, molecular dynamics analysis concluded that the target of antimicrobial peptide Bactenecin is MurB of A. baumannii, and identified other molecular targets of selected AMPs. Additionally, the oligomerization capacity of the selected AMPs was also investigated, and it was shown that the selected AMPs form oligomeric states, and interact with their molecular targets in that state. Experimental validation using purified AMPs and molecular targets needs to be done to confirm the interaction.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Sayani Sarkar
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Aruna Kumari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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Aggarwal R, Mahajan P, Pandiya S, Bajaj A, Verma SK, Yadav P, Kharat AS, Khan AU, Dua M, Johri AK. Antibiotic resistance: a global crisis, problems and solutions. Crit Rev Microbiol 2024:1-26. [PMID: 38381581 DOI: 10.1080/1040841x.2024.2313024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/28/2024] [Indexed: 02/23/2024]
Abstract
Healthy state is priority in today's world which can be achieved using effective medicines. But due to overuse and misuse of antibiotics, a menace of resistance has increased in pathogenic microbes. World Health Organization (WHO) has announced ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) as the top priority pathogens as these have developed resistance against certain antibiotics. To combat such a global issue, it is utmost important to identify novel therapeutic strategies/agents as an alternate to such antibiotics. To name certain antibiotic adjuvants including: inhibitors of beta-lactamase, efflux pumps and permeabilizers for outer membrane can potentially solve the antibiotic resistance problems. In this regard, inhibitors of lytic domain of lytic transglycosylases provide a novel way to not only act as an alternate to antibiotics but also capable of restoring the efficiency of previously resistant antibiotics. Further, use of bacteriophages is another promising strategy to deal with antibiotic resistant pathogens. Taking in consideration the alternatives of antibiotics, a green synthesis nanoparticle-based therapy exemplifies a good option to combat microbial resistance. As horizontal gene transfer (HGT) in bacteria facilitates the evolution of new resistance strains, therefore identifying the mechanism of resistance and development of inhibitors against it can be a novel approach to combat such problems. In our perspective, host-directed therapy (HDT) represents another promising strategy in combating antimicrobial resistance (AMR). This approach involves targeting specific factors within host cells that pathogens rely on for their survival, either through replication or persistence. As many new drugs are under clinical trials it is advisable that more clinical data and antimicrobial stewardship programs should be conducted to fully assess the clinical efficacy and safety of new therapeutic agents.
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Affiliation(s)
- Rupesh Aggarwal
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Pooja Mahajan
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Sameeksha Pandiya
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Aayushi Bajaj
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Shailendra Kumar Verma
- Center for Infectious Disease and Vaccine Research, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Puja Yadav
- Department of Microbiology, Central University of Haryana, Mahendergarh, India
| | - Arun S Kharat
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Asad Ullah Khan
- Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, India
| | - Meenakshi Dua
- School of Environmental Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Atul Kumar Johri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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Kulshrestha M, Tiwari M, Tiwari V. Bacteriophage therapy against ESKAPE bacterial pathogens: Current status, strategies, challenges, and future scope. Microb Pathog 2024; 186:106467. [PMID: 38036110 DOI: 10.1016/j.micpath.2023.106467] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 10/19/2023] [Accepted: 11/24/2023] [Indexed: 12/02/2023]
Abstract
The ESKAPE pathogens are the primary threat due to their constant spread of drug resistance worldwide. These pathogens are also regarded as opportunistic pathogens and could potentially cause nosocomial infections. Most of the ESKAPE pathogens have developed resistance to almost all the antibiotics that are used against them. Therefore, to deal with antimicrobial resistance, there is an urgent requirement for alternative non-antibiotic strategies to combat this rising issue of drug-resistant organisms. One of the promising alternatives to this scenario is implementing bacteriophage therapy. This under-explored mode of treatment in modern medicine has posed several concerns, such as preferable phages for the treatment, impact on the microbiome (or gut microflora), dose optimisation, safety, etc. The review will cover a rationale for phage therapy, clinical challenges, and propose phage therapy as an effective therapeutic against bacterial coinfections during pandemics. This review also addresses the expected uncertainties for administering the phage as a treatment against the ESKAPE pathogens and the advantages of using lytic phage over temperate, the immune response to phages, and phages in combinational therapies. The interaction between bacteria and bacteriophages in humans and countless animal models can also be used to design novel and futuristic therapeutics like personalised medicine or bacteriophages as anti-biofilm agents. Hence, this review explores different aspects of phage therapy and its potential to emerge as a frontline therapy against the ESKAPE bacterial pathogen.
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Affiliation(s)
- Mukta Kulshrestha
- Department of Biochemistry, Central University of Rajasthan, Ajmer, 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, 305817, India.
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Amaral SC, Pruski BB, de Freitas SB, Dos Santos LM, Hartwig DD. Biofilm formation in drug-resistant Acinetobacter baumannii and Acinetobacter nosocomialis isolates obtained from a university hospital in Pelotas, RS, Brazil. Lett Appl Microbiol 2023; 76:ovad094. [PMID: 37563082 DOI: 10.1093/lambio/ovad094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 06/29/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023]
Abstract
This study aimed to investigate the antibiotic resistance and biofilm formation of Acinetobacter calcoaceticus-A. baumannii (ACB) complex isolates recovered from a university hospital in Pelotas, RS, Brazil. The species were confirmed using gyrB multiplex and blaOXA-51-like genes PCR. The presence of the bfmRS virulence gene was evaluated by the PCR, and the isolates were classified based on their biofilm-forming ability on polystyrene (PO) and glass surfaces (TM). Out of 50 ACB complex isolates evaluated, 41 were identified as A. baumannii and nine as A. nosocomialis. The bfmRS gene was detected in 97.6% (40/41) of A. baumannii and 33.3% (3/9) of A. nosocomialis species. Forty-nine isolates exhibited a multidrug-resistant (MDR) profile, while one A. nosocomialis isolate presented an extensively drug-resistant (XDR) profile. All isolates were able of forming biofilms on PO surfaces and 98% (49/50) on TM surfaces. A significant correlation was observed between biofilm production on PO and TM surfaces (P < 0.05). However, no correlation was found between biofilms forming and the presence of the bfmRS gene or displaying a certain antibiotic resistance profile. In conclusion, A. baumannii and A. nosocomialis are frequent species causing nosocomial infections in a hospital in Pelotas, RS, Brazil, and both are capable of forming biofilms.
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Affiliation(s)
- Suélen Cavalheiro Amaral
- Laboratory of Bacteriology and Bioassays (LaBBio), Department of Microbiology and Parasitology, Biology Institute, Federal University of Pelotas, Pelotas, 96010900, RS, Brazil
- Center of Technological Development, Biotechnology, Federal University of Pelotas, Pelotas, 96010900, RS, Brazil
| | - Beatriz Bohns Pruski
- Laboratory of Bacteriology and Bioassays (LaBBio), Department of Microbiology and Parasitology, Biology Institute, Federal University of Pelotas, Pelotas, 96010900, RS, Brazil
| | - Stella Buchhorn de Freitas
- Laboratory of Bacteriology and Bioassays (LaBBio), Department of Microbiology and Parasitology, Biology Institute, Federal University of Pelotas, Pelotas, 96010900, RS, Brazil
| | - Lucas Moreira Dos Santos
- Center of Technological Development, Biotechnology, Federal University of Pelotas, Pelotas, 96010900, RS, Brazil
| | - Daiane Drawanz Hartwig
- Laboratory of Bacteriology and Bioassays (LaBBio), Department of Microbiology and Parasitology, Biology Institute, Federal University of Pelotas, Pelotas, 96010900, RS, Brazil
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Solanki V, Tiwari M, Tiwari V. Investigation of Peptidoglycan-Associated Lipoprotein of Acinetobacter baumannii and Its Interaction with Fibronectin To Find Its Therapeutic Potential. Infect Immun 2023; 91:e0002323. [PMID: 37017535 PMCID: PMC10187120 DOI: 10.1128/iai.00023-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 03/07/2023] [Indexed: 04/06/2023] Open
Abstract
Acinetobacter baumannii causes hospital-acquired infections and is responsible for high mortality and morbidity. The interaction of this bacterium with the host is critical in bacterial pathogenesis and infection. Here, we report the interaction of peptidoglycan-associated lipoprotein (PAL) of A. baumannii with host fibronectin (FN) to find its therapeutic potential. The proteome of A. baumannii was explored in the host-pathogen interaction database to filter out the PAL of the bacterial outer membrane that interacts with the host's FN protein. This interaction was confirmed experimentally using purified recombinant PAL and pure FN protein. To investigate the pleiotropic role of PAL protein, different biochemical assays using wild-type PAL and PAL mutants were performed. The result showed that PAL mediates bacterial pathogenesis, adherence, and invasion in host pulmonary epithelial cells and has a role in the biofilm formation, bacterial motility, and membrane integrity of bacteria. All of the results suggest that PAL's interaction with FN plays a vital role in host-cell interaction. In addition, the PAL protein also interacts with Toll-like receptor 2 and MARCO receptor, which suggests the role of PAL protein in innate immune responses. We have also investigated the therapeutic potential of this protein for vaccine and therapeutic design. Using reverse vaccinology, PAL's potential epitopes were filtered out that exhibit binding potential with host major histocompatibility complex class I (MHC-I), MHC-II, and B cells, suggesting that PAL protein is a potential vaccine target. The immune simulation showed that PAL protein could elevate innate and adaptive immune response with the generation of memory cells and would have subsequent potential to eliminate bacterial infection. Therefore, the present study highlights the interaction ability of a novel host-pathogen interacting partner (PAL-FN) and uncovers its therapeutic potential to combat infection caused by A. baumannii.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, Rajasthan, India
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CRISPR-Cas in Acinetobacter baumannii Contributes to Antibiotic Susceptibility by Targeting Endogenous AbaI. Microbiol Spectr 2022; 10:e0082922. [PMID: 35938813 PMCID: PMC9430643 DOI: 10.1128/spectrum.00829-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Acinetobacter baumannii is a well-known human opportunistic pathogen in nosocomial infections, and the emergence of multidrug-resistant Acinetobacter baumannii has become a complex problem for clinical anti-infective treatments. The ways this organism obtains multidrug resistance phenotype include horizontal gene transfer and other mechanisms, such as altered targets, decreased permeability, increased enzyme production, overexpression of efflux pumps, metabolic changes, and biofilm formation. A CRISPR-Cas system generally consists of a CRISPR array and one or more operons of cas genes, which can restrict horizontal gene transfer in bacteria. Nevertheless, it is unclear how CRISPR-Cas systems regulate antibiotic resistance in Acinetobacter baumannii. Thus, we sought to assess how CRISPR-Cas affects biofilm formation, membrane permeability, efflux pump, reactive oxygen species, and quorum sensing to clarify further the mechanism of CRISPR-Cas regulation of Acinetobacter baumannii antibiotic resistance. In the clinical isolate AB43, which has a complete I-Fb CRISPR-Cas system, we discovered that the Cas3 nuclease of this type I-F CRISPR-Cas system regulates Acinetobacter baumannii quorum sensing and has a unique function in changing drug resistance. As a result of quorum sensing, synthase abaI is reduced, allowing efflux pumps to decrease, biofilm formation to become weaker, reactive oxygen species to generate, and drug resistance to decrease in response to CRISPR-Cas activity. These observations suggest that the CRISPR-Cas system targeting endogenous abaI may boost bacterial antibiotic sensitivity. IMPORTANCE CRISPR-Cas systems are vital for genome editing, bacterial virulence, and antibiotic resistance. How CRISPR-Cas systems regulate antibiotic resistance in Acinetobacter baumannii is almost wholly unknown. In this study, we reveal that the quorum sensing regulator abaI mRNA was a primary target of the I-Fb CRISPR-Cas system and the cleavage activity of Cas3 was the most critical factor in regulating abaI mRNA degradation. These results advance our understanding of how CRISPR-Cas systems inhibit drug resistance. However, the mechanism of endogenous targeting of abaI by CRISPR-Cas needs to be further explored.
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Tiwari V. Pharmacophore screening, denovo designing, retrosynthetic analysis, and combinatorial synthesis of a novel lead VTRA1.1 against RecA protein of Acinetobacter baumannii. Chem Biol Drug Des 2022; 99:839-856. [PMID: 35278346 DOI: 10.1111/cbdd.14037] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/15/2022] [Accepted: 03/05/2022] [Indexed: 01/08/2023]
Abstract
Antibiotics and disinfectants resistance is acquired by activating RecA-mediated DNA repair, which maintains ROS-dependent DNA damage caused by the antimicrobial molecules. To increase the efficacy of different antimicrobials, an inhibitor can be developed against RecA protein. The present study aims to design a denovo inhibitor against RecA protein of Acinetobacter baumannii. Pharmacophore-based screening, molecular mechanics, molecular dynamics simulation (MDS), retrosynthetic analysis, and combinatorial synthesis were used to design lead VTRA1.1 against RecA of A. baumannii. Pharmacophore models (structure-based and ligand-based) were created, and a phase library of FDA-approved drugs was prepared. Screening of the phase library against these pharmacophore models selected thirteen lead molecules. These filtered leads were used for the denovo fragment-based design, which produced 253 combinations. These designed molecules were further analyzed for its interaction with active site of RecA that selected a hybrid VTRA1. Further, retrosynthetic analysis and combinatorial synthesis produced 1000 analogs of VTRA1 by more than 100 modifications. These analogs were used for XP docking, binding free energy calculation, and MDS analysis which finally select lead VTRA1.1 against RecA protein. Further, mutations at the interacting residues of RecA with VTRA1.1, alter the unfolding rate of RecA, which suggests the binding of VTRA1.1 to these residues may alter the stability of RecA. It is also found that VTRA1.1 had reduced interaction of RecA with LexA and ssDNA polydT, showing the lead's efficacy in controlling the SOS response. Further, it was also observed that VTRA1.1 does not contain any predicted human off-targets and no cytotoxicity to cell lines. As functional RecA is involved in antimicrobial resistance, denovo designed lead VTRA1.1 against RecA may be further developed as a significant combination for therapeutic uses against A. baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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Differential Gene Expression of Efflux Pumps and Porins in Clinical Isolates of MDR Acinetobacter baumannii. Life (Basel) 2022; 12:life12030419. [PMID: 35330171 PMCID: PMC8948634 DOI: 10.3390/life12030419] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
Background: Acinetobacter baumannii is an opportunistic pathogen associated with healthcare infections and high mortality rates in intensive care units all over the globe. Porins and efflux pumps over-expression have been reported as contributing factors in escalating drug resistance and rendering treatment ineffective. In this study, we investigated the mechanisms of multidrug resistance (MDR) in A. baumannii clinical isolates. Methods: A total of 30 A. baumannii isolates were included in the present study from Nehru Hospital (PGIMER-Chandigarh) located in North India. Kirby Bauer disk diffusion assay and MIC were performed to determine the antimicrobial susceptibility pattern. Screening of beta-lactamases was performed using PCR. Relative gene expression of four RND, one MATE efflux pump, and two outer membrane proteins were determined using RT-PCR. Molecular typing of 22 isolates was carried out using MLST Oxford scheme. Results: CarO porin genes showed over-expression in 63% isolates followed by adeGandabeM efflux pump downregulation/underexpression (<0.5 fold), suggesting the carbapenem-susceptible phenotypic nature of the isolates. High prevalence of VIM-2, NDM-1, and OXA-23 genes was observed in A. baumannii isolates. Interestingly, NDM-1 and OXA-58 were traced in 10 and3 A. baumannii isolates respectively; 13 of 22 (59%) isolates showed novel Sequence Types (STs) in the Multi-Locus Sequence Typing (MLST) analysis. ST 1087 was most commonly found ST among all others (16 STs). Conclusions: This study indicated a possible role of carO porin genes and adeG (RND) andabeM (MATE) efflux pumps in carbapenem susceptibility of A. baumannii. New STs were also reported in the majority of the isolates.
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Verma P, Tiwari M, Tiwari V. Efflux pumps in multidrug-resistant Acinetobacter baumannii: Current status and challenges in the discovery of efflux pumps inhibitors. Microb Pathog 2021; 152:104766. [PMID: 33545327 DOI: 10.1016/j.micpath.2021.104766] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 12/14/2022]
Abstract
Acinetobacter baumannii is an ESKAPE pathogen known to cause fatal nosocomial infections. With the surge of multidrug resistance (MDR) in the bacterial system, effective treatment measures have become very limited. The MDR in A. baumannii is contributed by various factors out of which efflux pumps have gained major attention due to their broad substrate specificity and wide distribution among bacterial species. The efflux pumps are involved in the MDR as well as contribute to other physiological processes in bacteria, therefore, it is critically important to inhibit efflux pumps in order to combat emerging resistance. The present review provides insight about the different efflux pump systems in A. baumannii and their role in multidrug resistance. A major focus has been put on the different strategies and alternate therapeutics to inhibit the efflux system. This includes use of different efflux pump inhibitors-natural, synthetic or combinatorial therapy. The use of phage therapy and nanoparticles for inhibiting efflux pumps have also been discussed here. Moreover, the present review provides the knowledge of barriers in development of efflux pump inhibitors (EPIs) and their approval for commercialization. Here, different prospectives have been discussed to improve the therapeutic development process and make it more compatible for clinical use.
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Affiliation(s)
- Privita Verma
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India.
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Serwecińska L, Kiedrzyńska E, Kiedrzyński M. A catchment-scale assessment of the sanitary condition of treated wastewater and river water based on fecal indicators and carbapenem-resistant Acinetobacter spp. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 750:142266. [PMID: 33182211 DOI: 10.1016/j.scitotenv.2020.142266] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/22/2020] [Accepted: 09/06/2020] [Indexed: 05/14/2023]
Abstract
Urbanization and population growth have created considerable sanitation challenges in cities and communities in many parts of Europe and the world. As such, it is imperative to identify the most environmentally-harmful microbiological and chemical sources of pollution, these being wastewater treatment plants (WWTPs) which release wastewater of low quality. In the present manuscript, an extensive study was performed of the sanitary conditions of river water and treated wastewater from seventeen WWTPs of various sizes along the Pilica River catchment in central Poland, with the aim of identifying "hot spots" in terms of most serious sources of sanitary hazards. The bacteriological risk for the river, including fecal indicator bacteria (FIB) such as coliforms, E.coli, enterococci, C. perfringens, and carbapenem-resistant Acinetobacter spp. (CRA) were assessed using classical microbiological methods, and the physicochemical parameters were also tested. The WWTPs, particularly the small ones (<2000 people equivalent, PE) demonstrated significant variation regarding the physicochemical parameters. Carbapenem-resistant Acinetobacter spp. bacteria growing at 42 °C were found in the effluent wastewaters of all tested municipal WWTPs, and in most of the Pilica River water samples, presenting a potential hazard to public health. A positive correlation was identified between E. coli and CRA abundance in treated wastewater; however, no such relationship was found in river water. It was found that seven small treatment plants discharged wastewater with very different microbiological parameters. Moreover, three small treatment plants serving only 0.56% of the population in the studied area continuously released extremely high microbiological contamination, constituting as much as 54-82% of fecal indicator bacteria loads in the area studied. Our findings show that this type of comprehensive analysis may enable assessment of the use of the entire catchment area, thus identifying the most serious threats to surface water quality and guiding the actions needed to improve the worst operating WWTPs.
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Affiliation(s)
- Liliana Serwecińska
- European Regional Centre for Ecohydrology of the Polish Academy of Sciences, Tylna 3, 90-364 Lodz, Poland
| | - Edyta Kiedrzyńska
- European Regional Centre for Ecohydrology of the Polish Academy of Sciences, Tylna 3, 90-364 Lodz, Poland; UNESCO Chair on Ecohydrology and Applied Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha 12/16, 90-237 Lodz, Poland.
| | - Marcin Kiedrzyński
- Department of Geobotany and Plant Ecology, Faculty of Biology and Environmental Protection, University of Lodz, Banacha12/16, 90-237 Lodz, Poland
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Jakovac S, Goić-Barišić I, Pirija M, Kovačić A, Hrenović J, Petrović T, Tutiš B, Tonkić M. Molecular Characterization and Survival of Carbapenem-Resistant Acinetobacter baumannii Isolated from Hospitalized Patients in Mostar, Bosnia and Herzegovina. Microb Drug Resist 2020; 27:383-390. [PMID: 32721271 DOI: 10.1089/mdr.2020.0163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Increasingly difficult treatment of multidrug-resistant (MDR) bacteria has become a global problem of the 21st century. Within a group of multiresistant bacteria, the Acinetobacter baumannii convincingly occupies the position at the top of the group designated as ESKAPE pathogens. In this study, 61 isolates of A. baumannii were recovered from different samples originating from various departments of the University Clinical Hospital Mostar during 2018. All of the isolates were identified using conventional phenotypic methods and the VITEK® 2 Compact System, and were confirmed by MALDI-TOF mass spectrometry. The minimum inhibitory concentrations (MICs) were determined by the microbroth dilution method using MICRONAUT-S MDR MRGN-Screening and VITEK 2 Compact System. All strains were resistant to carbapenems and classified in eight different resistotypes according to their antibiotic resistance and macrorestriction pulsed-field gel electrophoresis profiles, with all belonging to IC II. One isolate displayed resistance to colistin (MIC ≥16 mg/L). The presence of blaOXA genes encoding OXA-type carbapenemases was investigated by multiplex PCR and the Eazyplex® SuperBugAcineto system and showed 100% compatibility with the detection of acquired oxacillinases. Molecular characterization of the isolates tested in this study revealed the OXA-23- and OXA-40-like groups of acquired oxacillinases. Sequencing of two PCR products of the OXA-40-like group confirmed the presence of OXA-72. Survival assays with two selected isolates of A. baumannii encoding different mechanisms of carbapenem resistance revealed that one isolate was able to survive on a fragment of white laboratory coat during 90 days of monitoring. To the best of our knowledge, this is the first article to present the results of a comprehensive phenotypic, genotypic, and molecular analysis of A. baumannii isolates from the leading clinical hospital center in the southwestern part of Bosnia and Herzegovina, including data for the survival of this pathogen on the white laboratory coats used as compulsory medical clothing.
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Affiliation(s)
- Sanja Jakovac
- Institute for Microbiological Diagnostics, University Clinical Hospital Mostar and School of Medicine University of Mostar, Mostar, Bosnia and Herzegovina
| | - Ivana Goić-Barišić
- University Hospital of Split and University of Split School of Medicine, Split, Croatia
| | - Mario Pirija
- Department of Clinical Microbiology, University Hospital of Split, Split, Croatia
| | - Ana Kovačić
- Institute of Public Health of Split and Dalmatia Country, Split, Croatia
| | - Jasna Hrenović
- Department of Biology, Faculty of Science, University of Zagreb, Zagreb, Croatia
| | - Tanja Petrović
- Institute for Microbiological Diagnostics, University Clinical Hospital Mostar and School of Medicine University of Mostar, Mostar, Bosnia and Herzegovina
| | - Borka Tutiš
- University Clinical Hospital Mostar, Mostar, Bosnia and Herzegovina
| | - Marija Tonkić
- University Hospital of Split and University of Split School of Medicine, Split, Croatia
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Tiwari M, Kumar P, Tejavath KK, Tiwari V. Assessment of Molecular Mechanism of Gallate-Polyvinylpyrrolidone-Capped Hybrid Silver Nanoparticles against Carbapenem-Resistant Acinetobacter baumannii. ACS OMEGA 2020; 5:1206-1213. [PMID: 31984278 PMCID: PMC6977194 DOI: 10.1021/acsomega.9b03644] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 12/19/2019] [Indexed: 05/10/2023]
Abstract
Acinetobacter baumannii is an opportunistic nosocomial pathogen and causes bacteremia, urinary tract infections, meningitis, and pneumonia. The emergence of drug-resistant strain makes most of the current antibiotics ineffective. It is high time to screen some therapeutics against drug-resistant strains. Plant-based medicines have recently emerged as one of the important therapeutic choices. Therefore, in the present study, we have screened the metabolites of Phyllanthus emblica, Ocimum tenuiflorum, and Murraya koenigii for their antibacterial effect against carabapenem-resistant strain (RS-307) of A. baumannii. The result showed that the methanolic extract of P. emblica inhibits the growth of RS-307. The composition of this extract was determined using phytochemical screening and nuclear magnetic resonance (1D and 2D-NMR). The mechanism of action of the plant extract was validated by estimating reactive oxygen species (ROS), lipid peroxidation, protein carbonylation, and membrane damage. The result showed that treatment with this extract showed a significant elevation in the production of ROS generations, lipid peroxidation, and protein carbonylation. This confirms that plant extract treatment confirmed ROS-dependent membrane damage mechanism. The NMR result showed the presence of ethyl gallate, ellagic acid, chebulagic acid, quercetin, flavonoid, and alkaloid. To validate the antimicrobial activity of the secondary metabolite (i.e., gallic acid), we synthesized gallate-polyvinylpyrrolidone-capped hybrid silver nanoparticles (G-PVP-AgNPs) and characterized using Fourier transform infrared spectroscopy (FTIR). G-PVP-AgNPs showed good antimicrobial activity against RS-307, and its mechanism of action was investigated using fluorescence and transmission electron microscopy and FTIR that confirmed ROS-dependent killing mechanism. Therefore, the present study highlighted and recommended the use of G-PVP-AgNPs as suitable therapeutics against carbapenem-resistant A. baumannii.
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Affiliation(s)
- Monalisa Tiwari
- Department
of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Pawan Kumar
- Department
of NMR, All India Institute of Medical Sciences, New Delhi 110029, India
| | - Kiran Kumar Tejavath
- Department
of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
- KKT: E-mail:
| | - Vishvanath Tiwari
- Department
of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
- VT: E-mail: , ; Phone: + 91-850-300-2573
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14
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Biswas D, Tiwari M, Tiwari V. Molecular mechanism of antimicrobial activity of chlorhexidine against carbapenem-resistant Acinetobacter baumannii. PLoS One 2019; 14:e0224107. [PMID: 31661500 PMCID: PMC6818764 DOI: 10.1371/journal.pone.0224107] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 10/04/2019] [Indexed: 02/07/2023] Open
Abstract
Acinetobacter baumannii causes hospital-acquired infections, especially in those with impaired immune function. Biocides or disinfectants are widely used antibacterial agents used to eradicate the effect of A. baumannii on inanimate objects and health care environments. In the current study, the antimicrobial activity of chlorhexidine has been investigated against carbapenem-resistant (RS-307, RS-7434, RS-6694, and RS-122), and sensitive (ATCC-19606 and RS-10953) strains of A. baumannii. We have determined growth kinetics, antimicrobial susceptibility, ROS production, lipid peroxidation, cell viability using flow cytometry assay (FACS), and membrane integrity by scanning electron microscope (SEM). The effect of chlorhexidine on the bacterial membrane has also been investigated using Fourier transform infrared (FTIR) spectroscopy. The present study showed that 32μg/ml chlorhexidine treatment results in the decreased bacterial growth, CFU count and cell viability. The antibacterial activity of chlorhexidine is due to the elevated ROS production and higher lipid peroxidation. These biochemical changes result in the membrane damage and alteration in the membrane proteins, phospholipids, carbohydrates, nucleic acids as evident from the FTIR and SEM data. Therefore, chlorhexidine has the potential to be used in the hospital setups to remove the spread of A. baumannii.
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Affiliation(s)
- Deepika Biswas
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
- * E-mail: ,
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15
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Kumar S, Patil PP, Singhal L, Ray P, Patil PB, Gautam V. Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii isolates reveals the emergence of bla OXA-23 and bla NDM-1 encoding international clones in India. INFECTION GENETICS AND EVOLUTION 2019; 75:103986. [PMID: 31362071 DOI: 10.1016/j.meegid.2019.103986] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/18/2019] [Accepted: 07/26/2019] [Indexed: 01/09/2023]
Abstract
Acinetobacter baumannii is a nosocomial pathogen increasingly affecting the critically ill patients and represents a major public health challenge. Carbapenem-resistant A. baumannii (CRAB) is found to be associated with International Clones (ICs) and different classes of carbapenemases. The objective of the present study was to investigate the prevalence of carbapenem resistance genes, clonal relationship and genetic structure of clinical isolates of A. baumannii. In the present study, multi-locus sequence typing (MLSTOX) and analysis were carried out using Oxford scheme for 86 clinical isolates of CRAB along with 11 carbapenem sensitive A. baumannii (CSAB) collected over a period of two years (2014-2016) from two tertiary care hospitals of North India. We observed a high prevalence of the blaOXA-23-like (97.7%) among the CRAB followed by blaNDM-1 (29.1%) and blaOXA58-like (3.5%). Forty-seven Sequence Types (STs) were represented by all 97 isolates, out of which, 28 (59.6%) were novel STs that were assigned to 41 isolates. STs 451 (13%), 447 (7%), 195 (6%) and 848 (5%) were the most common STs. The majority of CRAB isolates (44.3%) belonged to the CC92, followed by the CC447 (15.1%), CC109 (9.3%) and CC110 (3.4%), which corresponds to the IC2, 8, 1 and 7 respectively. Phylogenetic and recombination analysis suggested two major and one minor lineage in the population. Further linkage disequilibrium analysis suggested clonal nature of the population as recombination was noticed at a low frequency, which was not enough to split the clonal relationship. The knowledge of genetic structure of CRAB from this study will be invaluable to illustrate epidemiology, surveillance and understanding its global diversity.
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Affiliation(s)
- Sunil Kumar
- Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India; Department of Biotechnology, Maharishi Markandeshwar (Deemed to be) University, Mullana, Ambala, Haryana 133207, India
| | - Prashant P Patil
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Sector - 39A, Chandigarh 160036, India
| | - Lipika Singhal
- Government Medical College and Hospital, Sector -32B, Chandigarh 160030, India
| | - Pallab Ray
- Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India
| | - Prabhu B Patil
- Bacterial Genomics and Evolution Laboratory, CSIR-Institute of Microbial Technology, Sector - 39A, Chandigarh 160036, India.
| | - Vikas Gautam
- Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh 160012, India.
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16
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Tiwari V. Molecular insight into the therapeutic potential of phytoconstituents targeting protein conformation and their expression. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2019; 52:225-237. [PMID: 30599902 PMCID: PMC7126799 DOI: 10.1016/j.phymed.2018.09.214] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 09/03/2018] [Accepted: 09/25/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Native protein conformation is essential for the functional activity of the proteins and enzymes. Defects in conformation or alterations in expression of the proteins have been reported in various diseases. PURPOSE The aim of this study is to review the molecular insight into the therapeutic potential of phytoconstituents targeting protein conformations or expressions. METHODS Published literatures were searched in PubMed, Scopus, Web of Science; Article published till Dec 2017 were extracted. The literature was assessed from the Central University of Rajasthan, India. Present study evaluate article based on the role of active plant constituents on the conformation and expression of the different proteins. RESULTS Plant components play their role either at the molecular level or cellular level and exhibit antibacterial, antiviral, anti-neurodegenerative and other activities. Plant active compounds isolated from different plants may either stabilize or destabilize the conformation of proteins or alter expression level of the protein involved in these diseases, therefore, can play a significant role in preventing diseases caused by the alteration in these proteins. CONCLUSION In the present article, we have reviewed the molecular mechanism of plant active compounds, their target proteins, methods of extraction and identification, and their biological significances. Therefore, a proper understanding of the effect of these herbal molecules on the concerned proteins may help to develop new herbal-based therapeutics for various diseases.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer 305817, India.
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17
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Tiwari V, Rajeswari MR, Tiwari M. Proteomic analysis of iron-regulated membrane proteins identify FhuE receptor as a target to inhibit siderophore-mediated iron acquisition in Acinetobacter baumannii. Int J Biol Macromol 2018; 125:1156-1167. [PMID: 30579900 DOI: 10.1016/j.ijbiomac.2018.12.173] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 11/02/2018] [Accepted: 12/19/2018] [Indexed: 11/27/2022]
Abstract
Survival of the Acinetobacter baumannii inside host requires different micronutrients such as iron, but their bioavailability is limited because of nutritional immunity created by host. A. baumannii has to develop mechanisms to acquire nutrient iron during infection. The present study is an attempt to identify membrane proteins involved in iron sequestration mechanism of A. baumannii using two-dimensional electrophoresis and LC-MS/MS analysis. The identified iron-regulated membrane protein (IRMP) of A. baumannii was used for its interaction studies with different siderophores, and designing of the inhibitor against A. baumannii targeting this IRMP. Membrane proteomic results identified over-expression of four membrane proteins (Fhu-E receptor, ferric-acinetobactin receptor, ferrienterochelin receptor, and ferric siderophore receptor) under iron-limited condition. A. baumannii produces siderophores that have good interaction with the FhuE receptor. Result also showed that FhuE receptor has interaction with siderophores produced by other bacteria. Interaction of FhuE receptor and siderophores helps in iron sequestration and survival of Acinetobacter under nutritional immunity imposed by the host. Hence it becomes essential to find a potential inhibitor for the FhuE receptor that can inhibit the survival of A. baumannii in the host. In-silico screening, and molecular mechanics studies identified ZINC03794794 and ZINC01530652 as a likely lead to design inhibitor against the FhuE receptor of A. baumannii. The designed inhibitor is experimentally validated for its antibacterial activity on the A. baumannii. Therefore, designed inhibitor interferes with the iron acquisition mechanism of Acinetobacter hence may prove useful for preventing infection caused by A. baumannii by limiting nutrient availability.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer 305817, India.
| | - Moganty R Rajeswari
- Department of Biochemistry, All India Institute of Medical Sciences, New Delhi, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer 305817, India
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18
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Biswas D, Tiwari M, Tiwari V. Comparative mechanism based study on disinfectants against multidrug-resistant Acinetobacter baumannii. J Cell Biochem 2018; 119:10314-10326. [PMID: 30145822 DOI: 10.1002/jcb.27373] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/28/2018] [Indexed: 12/19/2022]
Abstract
Acinetobacter baumannii has emerged as a hospital-acquired pathogen and has spread in the hospital settings, leading to enhanced nosocomial outbreaks associated with high death rates. Therefore, the aim of the current study is to determine the effective concentration of disinfectants like sodium hypochlorite, hydrogen peroxide, and chlorine dioxide, against multidrug-resistant (MDR) strains of A. baumannii. In this study, we have investigated the effect of disinfectants on different MDR strains i.e. RS307, RS6694, RS7434, RS10953, RS122, and sensitive strain ATCC-19606 of A. baumannii, via differential growth curves analysis, disc diffusion assay, estimation of reactive oxygen species (ROS), lipid peroxidation, and protein carbonylation. All the results collectively showed that 1% sodium hypochlorite (P value < 0.0027), 2.5% hydrogen peroxide (P value = 0.0032), and 10 mM (P value = 0.017) chlorine dioxide significantly inhibit the growth of MDR strains of A. baumannii. A significant increase in the ROS generations, altered lipid peroxidation, and a decrease in protein carbonylation was also observed after treatment with disinfectants, which confirmed its ROS-dependent damage mechanism. These disinfectants also enhance the membrane leakage of reducing sugar, protein, and DNA. The current study highlights and recommends the use of 2.5% hydrogen peroxide to control the MDR strains of A. baumannii in the hospital setup. Therefore, the present results will help in selecting concentrations of different disinfectants for regular use in hospital setups to eradicate the multidrug-resistant A. baumannii from the hospital setup.
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Affiliation(s)
- Deepika Biswas
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, India
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19
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Targeting Outer Membrane Protein Component AdeC for the Discovery of Efflux Pump Inhibitor against AdeABC Efflux Pump of Multidrug Resistant Acinetobacter baumannii. Cell Biochem Biophys 2018; 76:391-400. [PMID: 29926429 DOI: 10.1007/s12013-018-0846-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/07/2018] [Indexed: 01/19/2023]
Abstract
The structure and functioning of multidrug efflux systems provide us with a better understanding of the transport of various antibiotics, thus giving a path for the discovery of effective compounds for combating the multidrug resistance in Acinetobacter baumannii. In the present study, a number of computational techniques have been used to search for an inhibitor for the RND efflux pump, AdeABC, of A. baumannii targeting specifically its outermost component, i.e., AdeC. We have prepared the three-dimensional structure for AdeC using MODELLER v9.16 and identified its active binding site using SiteMap. Using high-throughput virtual screening, we identified compounds from a large library of biogenic compounds on the basis of their effective interaction at the binding site of AdeC. The validation of docking step was performed by plotting ROC curve (enrichment calculations). The docked complexes were further analyzed for their binding free energies by molecular mechanics using Generalized Born model and Solvent Accessibility (MMGBSA). The molecular dynamics simulation was performed for AdeC-ZINC77257599 complex using GROMACS. The present rational drug designing, molecular mechanics and molecular dynamics data provided an inhibitor, i.e, ZINC77257599 [(3R,4Z,6E,8E)-3-hydroxy-2,2,4-trimethyl-10-oxazol-5-yl-deca-4,6,8-trienamide], for the outer membrane protein component (AdeC) of efflux pump AdeABC of A. baumannii.
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20
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Solanki V, Tiwari V. Subtractive proteomics to identify novel drug targets and reverse vaccinology for the development of chimeric vaccine against Acinetobacter baumannii. Sci Rep 2018; 8:9044. [PMID: 29899345 PMCID: PMC5997985 DOI: 10.1038/s41598-018-26689-7] [Citation(s) in RCA: 164] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/17/2018] [Indexed: 11/24/2022] Open
Abstract
The emergence of drug-resistant Acinetobacter baumannii is the global health problem associated with high mortality and morbidity. Therefore it is high time to find a suitable therapeutics for this pathogen. In the present study, subtractive proteomics along with reverse vaccinology approaches were used to predict suitable therapeutics against A. baumannii. Using subtractive proteomics, we have identified promiscuous antigenic membrane proteins that contain the virulence factors, resistance factors and essentiality factor for this pathogenic bacteria. Selected promiscuous targeted membrane proteins were used for the design of chimeric-subunit vaccine with the help of reverse vaccinology. Available best tools and servers were used for the identification of MHC class I, II and B cell epitopes. All selected epitopes were further shortlisted computationally to know their immunogenicity, antigenicity, allergenicity, conservancy and toxicity potentials. Immunogenic predicted promiscuous peptides used for the development of chimeric subunit vaccine with immune-modulating adjuvants, linkers, and PADRE (Pan HLA-DR epitopes) amino acid sequence. Designed vaccine construct V4 also interact with the MHC, and TLR4/MD2 complex as confirm by docking and molecular dynamics simulation studies. Therefore designed vaccine construct V4 can be developed to control the host-pathogen interaction or infection caused by A. baumannii.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India.
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21
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Tiwari V, Mishra N, Gadani K, Solanki PS, Shah NA, Tiwari M. Mechanism of Anti-bacterial Activity of Zinc Oxide Nanoparticle Against Carbapenem-Resistant Acinetobacter baumannii. Front Microbiol 2018; 9:1218. [PMID: 29928271 PMCID: PMC5997932 DOI: 10.3389/fmicb.2018.01218] [Citation(s) in RCA: 198] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 05/18/2018] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii is a multi-drug resistant opportunistic pathogen, which causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Carbapenems (beta-lactam) are most effective antibiotics till now against A. baumannii, but the development of resistance against it may lead to high mortality. Therefore, it is of utmost importance to develop an alternative drug against A. baumannii. In the present study, we have synthesized ZnO nanoparticle (ZnO-NP) and characterized by X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy and UV-Visible spectroscopy. Prepared ZnO-NPs have the size of 30 nm and have different characteristics of ZnO-NPs. Growth kinetics and disk diffusion assay showed that ZnO-NP demonstrated good antibacterial activity against carbapenem resistant A. baumannii. We have also investigated the mechanism of action of ZnO-NPs on the carbapenem resistant strain of A. baumannii. The proposed mechanism of action of ZnO involves the production of reactive oxygen species, which elevates membrane lipid peroxidation that causes membrane leakage of reducing sugars, DNA, proteins, and reduces cell viability. These results demonstrate that ZnO-NP could be developed as alternative therapeutics against A. baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Neha Mishra
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Keval Gadani
- Department of Physics, Saurashtra University, Rajkot, India
| | - P. S. Solanki
- Department of Physics, Saurashtra University, Rajkot, India
| | - N. A. Shah
- Department of Physics, Saurashtra University, Rajkot, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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22
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Tran TB, Wang J, Doi Y, Velkov T, Bergen PJ, Li J. Novel Polymyxin Combination With Antineoplastic Mitotane Improved the Bacterial Killing Against Polymyxin-Resistant Multidrug-Resistant Gram-Negative Pathogens. Front Microbiol 2018; 9:721. [PMID: 29706941 PMCID: PMC5906568 DOI: 10.3389/fmicb.2018.00721] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 03/27/2018] [Indexed: 11/13/2022] Open
Abstract
Due to limited new antibiotics, polymyxins are increasingly used to treat multidrug-resistant (MDR) Gram-negative bacteria, in particular carbapenem-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae. Unfortunately, polymyxin monotherapy has led to the emergence of resistance. Polymyxin combination therapy has been demonstrated to improve bacterial killing and prevent the emergence of resistance. From a preliminary screening of an FDA drug library, we identified antineoplastic mitotane as a potential candidate for combination therapy with polymyxin B against polymyxin-resistant Gram-negative bacteria. Here, we demonstrated that the combination of polymyxin B with mitotane enhances the in vitro antimicrobial activity of polymyxin B against 10 strains of A. baumannii, P. aeruginosa, and K. pneumoniae, including polymyxin-resistant MDR clinical isolates. Time-kill studies showed that the combination of polymyxin B (2 mg/L) and mitotane (4 mg/L) provided superior bacterial killing against all strains during the first 6 h of treatment, compared to monotherapies, and prevented regrowth and emergence of polymyxin resistance in the polymyxin-susceptible isolates. Electron microscopy imaging revealed that the combination potentially affected cell division in A. baumannii. The enhanced antimicrobial activity of the combination was confirmed in a mouse burn infection model against a polymyxin-resistant A. baumannii isolate. As mitotane is hydrophobic, it was very likely that the synergistic killing of the combination resulted from that polymyxin B permeabilized the outer membrane of the Gram-negative bacteria and allowed mitotane to enter bacterial cells and exert its antimicrobial effect. These results have important implications for repositioning non-antibiotic drugs for antimicrobial purposes, which may expedite the discovery of novel therapies to combat the rapid emergence of antibiotic resistance.
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Affiliation(s)
- Thien B. Tran
- Monash Biomedicine Discovery Institute, Department of Microbiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Jiping Wang
- Monash Biomedicine Discovery Institute, Department of Microbiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Yohei Doi
- Division of Infectious Diseases, Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Tony Velkov
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
- Department of Pharmacology and Therapeutics, School of Biomedical Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Phillip J. Bergen
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
- Centre for Medicine Use and Safety, Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, VIC, Australia
| | - Jian Li
- Monash Biomedicine Discovery Institute, Department of Microbiology, School of Biomedical Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
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Solanki V, Tiwari M, Tiwari V. Host-bacteria interaction and adhesin study for development of therapeutics. Int J Biol Macromol 2018; 112:54-64. [PMID: 29414732 DOI: 10.1016/j.ijbiomac.2018.01.151] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/17/2018] [Accepted: 01/21/2018] [Indexed: 12/15/2022]
Abstract
Host-pathogen interaction is one of the most important areas of study to understand the adhesion of the pathogen to the host organisms. To adhere on the host cell surface, bacteria assemble the diverse adhesive structures on its surface, which play a foremost role in targeting to the host cell. We have highlighted different bacterial adhesins which are either protein mediated or glycan mediated. The present article listed examples of different bacterial adhesin proteins involved in the interactions with their host, types and subtypes of the fimbriae and non-fimbriae bacterial adhesins. Different bacterial surface adhesin subunits interact with host via different host surface biomolecules. We have also discussed the interactome of some of the pathogens with their host. Therefore, the present study will help researchers to have a detailed understanding of different interacting bacterial adhesins and henceforth, develop new therapies, adhesin specific antibodies and vaccines, which can effectively control pathogenicity of the pathogens.
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Affiliation(s)
- Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer 305817, India.
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Tiwari V, Tiwari M, Biswas D. Rationale and design of an inhibitor of RecA protein as an inhibitor of Acinetobacter baumannii. J Antibiot (Tokyo) 2018; 71:522-534. [PMID: 29410519 DOI: 10.1038/s41429-018-0026-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Revised: 12/23/2017] [Accepted: 12/25/2017] [Indexed: 11/09/2022]
Abstract
Acinetobacter baumannii is one of the ESKAPE pathogen, which causes pneumonia, urinary tract infections, and is linked to high degree of morbidity and mortality. One-way antibiotic and disinfectant resistance is acquired by the activation of RecA-mediated DNA repair (SOS-response) that maintain ROS-dependent DNA damage caused by these anti-bacterial molecules. To increase the efficacy of different anti-microbial, there is a need to design an inhibitor against RecA of A. baumannii. We have performed homology modeling to generate the structure of RecA, followed by model refinement and validation. High-throughput virtual screening of 1,80,313 primary and secondary metabolites against RecA was performed in HTVS, SP, and XP docking modes. The selected 195 compounds were further analyzed for binding free energy by molecular mechanics approach. The selected top two molecules from molecular mechanics approach were further validated by molecular dynamics simulation (MDS). In-silico high-throughput virtual screening and MDS validation identified ZINC01530654 or (+-)-2-((4-((7-Chloro-4-quinolyl)amino)pentyl)ethylamino)ethanol sulfate (or hydroxychloroquine sulfate) as a possible lead molecule binding to RecA protein. We have experimentally determined the mechanism of ZINC01530654 to RecA protein. These findings suggest a strategy to chemically inhibit the vital process controlled by RecA that could be helpful for the development of new antibacterial agents.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India.
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Deepika Biswas
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
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Alhaddad MS, AlBarjas AK, Alhammar LE, Al Rashed AS, Badger-Emeka LI. Molecular Characterization and Antibiotic Susceptibility Pattern of Acinetobacter Baumannii Isolated in Intensive Care Unit Patients in Al-Hassa, Kingdom of Saudi Arabia. Int J Appl Basic Med Res 2018; 8:19-23. [PMID: 29552530 PMCID: PMC5846213 DOI: 10.4103/ijabmr.ijabmr_91_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background: Acinetobacter baumannii, is an emerging nosocomial multidrug resistance pathogen with the rapid spread of clones being reported in health-care settings and hospitals worldwide. Carbapenem resistance in this bacterium has been attributed to D OXA β-lactamases with OXA-51-like β-lactamase, being present in all A. baumannii isolate. The present study looks into the antibiotics susceptibility and molecular characterization of clinical A. baumannii isolates from Intensive Care Unit (ICU) samples in Al-Hofuf, South-eastern region of Saudi Arabia. Materials and Methods: Eleven strains of ICU A. baumanni i isolates were used for the investigation. Bacteria isolation was by basic microbiological techniques. Organisms identification and antibiogram susceptibility testing was by the BioMerieux VITEK 2 compact automated system (BioMerieux, Marcy I'Etoile France), according to the manufacturers guidelines. Confirmation of A. baumannii was by the presence of the OX-51 gene, also, carbapenemase encoding resistant genesblaOXA-23, blaOXA-40, and blaOXA-51, were analyzed using multiplex PCR. The Student's t test was used to analyze the obtained data for between group comparisons with statistically significance level set at P < 0.05. Results: Eight of the isolates were confirmed to be A. baumannii. Five of which were resistant to the carbapenems against which they had been tested. One isolate was resistant to tigecycline, whereas three tested intermediate to the drug. OXA-23 was detected in isolates 1, 4, 5, 6, and 7. Conclusion: It can, therefore, be concluded that the probable predominate carbapenems resistant genes in ICU isolates from the present investigation, are those associated with OXA-23.
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Affiliation(s)
| | | | | | | | - Lorina Ineta Badger-Emeka
- Department of Biomedical Sciences, Division of Microbiology, College of Medicine, King Faisal University, Al-Hassa, Kingdom of Saudi Arabia
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Verma P, Maurya P, Tiwari M, Tiwari V. In-silico interaction studies suggest RND efflux pump mediates polymyxin resistance in Acinetobacter baumannii. J Biomol Struct Dyn 2017; 37:95-103. [DOI: 10.1080/07391102.2017.1418680] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Privita Verma
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer-305817, India
| | - Pramila Maurya
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer-305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer-305817, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer-305817, India
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Tiwari V, Patel V, Tiwari M. In-silico screening and experimental validation reveal L-Adrenaline as anti-biofilm molecule against biofilm-associated protein (Bap) producing Acinetobacter baumannii. Int J Biol Macromol 2017; 107:1242-1252. [PMID: 28964839 DOI: 10.1016/j.ijbiomac.2017.09.105] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/25/2017] [Accepted: 09/26/2017] [Indexed: 12/15/2022]
Abstract
Acinetobacter baumannii, an ESKAPE pathogen, causes various nosocomial infections and has capacity to produce biofilm. Biofilm produced by this bacterium is highly tolerant to environmental factors and different antibiotics. Biofilm-associated protein (Bap) plays a significant role in the biofilm formation by A. baumannii and found in the extra cellular matrix of the biofilm. Therefore, it becomes essential to find a potential drug against Bap that has capacity to inhibit biofilm formation by A. baumannii. In-silico screening, molecular mechanics and molecular dynamics studies identified ZINC00039089 (L-Adrenaline) as an inhibitor for Bap of A. baumannii. Recently, it is reported that Bap can form amyloid like structure; hence we have created dimer of Bap protein. This inhibitor can bind to dimeric Bap with good affinity. It confirms that ZINC00039089 (L-Adrenaline) can bind with Bap monomer as well as oligomeric Bap, responsible for amyloid formation and biofilm formation. Hence, we have tested Adrenaline as an anti-biofilm molecule and determined its IC50 value against biofilm. The result showed Adrenaline has anti-biofilm activity with IC50 value of 75μg/ml. Therefore; our finding suggests that L-Adrenaline can be developed to inhibit biofilm formation by carbapenem resistant strain of Acinetobacter baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India.
| | - Varsha Patel
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Bandarsindri, Ajmer, 305817, India
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Tiwari V, Tiwari D, Patel V, Tiwari M. Effect of secondary metabolite of Actinidia deliciosa on the biofilm and extra-cellular matrix components of Acinetobacter baumannii. Microb Pathog 2017; 110:345-351. [DOI: 10.1016/j.micpath.2017.07.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 06/20/2017] [Accepted: 07/10/2017] [Indexed: 12/31/2022]
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Tiwari V, Tiwari M, Solanki V. Polyvinylpyrrolidone-Capped Silver Nanoparticle Inhibits Infection of Carbapenem-Resistant Strain of Acinetobacter baumannii in the Human Pulmonary Epithelial Cell. Front Immunol 2017; 8:973. [PMID: 28861082 PMCID: PMC5561010 DOI: 10.3389/fimmu.2017.00973] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Accepted: 07/31/2017] [Indexed: 11/13/2022] Open
Abstract
Acinetobacter baumannii, an opportunistic ESKAPE pathogen, causes respiratory and urinary tract infections. Its prevalence increases gradually in the clinical setup. Pathogenicity of Acinetobacter is significantly influenced by its ability to infect and survive in human pulmonary cells. Therefore, it is important to study the infection of A. baumannii in human pulmonary host cell (A-549), monitoring surface interacting and internalized bacteria. It was found that during infection of A. baumannii, about 40% bacteria adhered to A-549, whereas 20% got internalized inside pulmonary cell and induces threefold increase in the reactive oxygen species production. We have synthesized polyvinylpyrrolidone (PVP)-capped AgNPs using chemical methods and tested its efficacy against carbapenem-resistant strain of A. baumannii. PVP-capped silver nanoparticles (PVP-AgNPs) (30 µM) have shown antibacterial activity against carbapenem-resistant strain of A. baumannii and this concentration does not have any cytotoxic effect on the human pulmonary cell line (IC50 is 130 µM). Similarly, PVP-AgNPs treatment decreases 80% viability of intracellular bacteria, decreases adherence of A. baumannii to A-549 (40 to 2.2%), and decreases intracellular concentration (20 to 1.3%) of A. baumannii. This concludes that PVP-AgNPs can be developed as a substitute for carbapenem to control the infection caused by carbapenem-resistant A. baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
| | - Vandana Solanki
- Department of Biochemistry, Central University of Rajasthan, Ajmer, India
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Verma P, Tiwari M, Tiwari V. In silico high-throughput virtual screening and molecular dynamics simulation study to identify inhibitor for AdeABC efflux pump of Acinetobacter baumannii. J Biomol Struct Dyn 2017; 36:1182-1194. [PMID: 28393677 DOI: 10.1080/07391102.2017.1317025] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Emergence of multi-drug resistant strains of Acinetobacter baumannii has caused significant health problems and is responsible for high morbidity and mortality. Overexpression of AdeABC efflux system is one of the major mechanisms. In this study, we have focused on overcoming the drug resistance by identifying inhibitors that can effectively bind and inhibit integral membrane protein, AdeB of this efflux pump. We performed homology modeling to generate structure of AdeB using MODELLER v9.16 followed by model refinement using 3D-Refine tool and validated using PSVS, ProsaWeb, ERRAT, etc. The energy minimization of modeled protein was done using Protein preparation wizard application included in Schrodinger suite. High-throughput virtual screening of 159,868 medicinal compounds against AdeB was performed using three sequential docking modes (i.e. HTVS, SP and XP). Furthermore, absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis was done using QIKPROP. The selected 123 compounds were further analyzed for binding free energy by molecular mechanics (using prime MM-GBSA). We have also performed enrichment study (ROC curve analysis) to validate our docking results. The selected molecule and its interaction with AdeB were validated by molecular dynamics simulation (MDS) using GROMACS v5.1.4. In silico high-throughput virtual screening and MDS validation identified ZINC01155930 ((4R)-3-(cycloheptoxycarbonyl)-4-(4-etochromen-3-yl)-2-methyl-4,6,7,8-tetrahydroquinolin-5-olate) as a possible inhibitor for AdeB. Hence, it might be a suitable efflux pump inhibitor worthy of further investigation in order to be used for controlling infections caused by Acinetobacter baumannii.
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Affiliation(s)
- Privita Verma
- a Department of Biochemistry , Central University of Rajasthan , Bandarsindri, Ajmer 305817 , India
| | - Monalisa Tiwari
- a Department of Biochemistry , Central University of Rajasthan , Bandarsindri, Ajmer 305817 , India
| | - Vishvanath Tiwari
- a Department of Biochemistry , Central University of Rajasthan , Bandarsindri, Ajmer 305817 , India
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Dang B, Mao D, Luo Y. Complete Nucleotide Sequence of pGA45, a 140,698-bp IncFIIY Plasmid Encoding bla IMI-3-Mediated Carbapenem Resistance, from River Sediment. Front Microbiol 2016; 7:188. [PMID: 26941718 PMCID: PMC4764695 DOI: 10.3389/fmicb.2016.00188] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Accepted: 02/03/2016] [Indexed: 12/22/2022] Open
Abstract
Plasmid pGA45 was isolated from the sediments of Haihe River using Escherichia coli CV601 (gfp-tagged) as recipients and indigenous bacteria from sediment as donors. This plasmid confers reduced susceptibility to imipenem which belongs to carbapenem group. Plasmid pGA45 was fully sequenced on an Illumina HiSeq 2000 sequencing system. The complete sequence of plasmid pGA45 was 140,698 bp in length with an average G + C content of 52.03%. Sequence analysis shows that pGA45 belongs to IncFIIY group and harbors a backbone region which shares high homology and gene synteny to several other IncF plasmids including pNDM1_EC14653, pYDC644, pNDM-Ec1GN574, pRJF866, pKOX_NDM1, and pP10164-NDM. In addition to the backbone region, plasmid pGA45 harbors two notable features including one blaIMI-3-containing region and one type VI secretion system region. The blaIMI-3-containing region is responsible for bacteria carbapenem resistance and the type VI secretion system region is probably involved in bacteria virulence, respectively. Plasmid pGA45 represents the first complete nucleotide sequence of the blaIMI-harboring plasmid from environment sample and the sequencing of this plasmid provided insight into the architecture used for the dissemination of blaIMI carbapenemase genes.
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Affiliation(s)
- Bingjun Dang
- School of Environmental Science and Engineering, Tianjin UniversityTianjin, China; Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai UniversityTianjin, China
| | - Daqing Mao
- School of Environmental Science and Engineering, Tianjin University Tianjin, China
| | - Yi Luo
- Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, College of Environmental Science and Engineering, Nankai University Tianjin, China
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Tiwari M, Roy R, Tiwari V. Screening of Herbal-Based Bioactive Extract Against Carbapenem-Resistant Strain of Acinetobacter baumannii. Microb Drug Resist 2016; 22:364-71. [PMID: 26910023 DOI: 10.1089/mdr.2015.0270] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Acinetobacter baumannii is grouped in the ESKAPE pathogens by Infectious Disease Society of America, which is linked to high degree of morbidity, mortality, and increased costs. The high level of acquired and intrinsic resistance mechanisms of these bacteria makes it an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In this study, methanolic extracts of six medicinal plants were subjected to phytochemical screening and their antimicrobial activity was tested against two strains of A. baumannii (ATCC 19606, carbapenem-sensitive strain, and RS 307, carbapenem-resistant strain). Synergistic effect of the plant extracts and antibiotics was also tested. Bael or Aegle marmelos contains tannin, phenol, terpenoids, glycoside, alkaloids, coumarine, steroid, and quinones. Flowers of madar or Calotropis procera possess tannin, phenol, terpenoids, glycoside, quinone, anthraquinone, anthocyanin, coumarin, and steroid. An inhibitory growth curve was seen for both the bacterial strains when treated with A. marmelos, Curcuma longa, and leaves and flowers of C. procera. Antibiotics alone showed a small zone of inhibition, but when used with herbal extracts they exhibited larger zone of inhibition. Synergistic effect of A. marmelos and imipenem was the best against both the strains of A. baumannii. From this study, it can be concluded that extracts from A. marmelos and leaves and flowers of C. procera exhibited the most effective antibacterial activity. These herbal extracts may be used to screen the bioactive compound against the carbapenem-resistant strain of A. baumannii.
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Affiliation(s)
- Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan , Ajmer, India
| | - Ranita Roy
- Department of Biochemistry, Central University of Rajasthan , Ajmer, India
| | - Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan , Ajmer, India
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Li P, Niu W, Li H, Lei H, Liu W, Zhao X, Guo L, Zou D, Yuan X, Liu H, Yuan J, Bai C. Rapid detection of Acinetobacter baumannii and molecular epidemiology of carbapenem-resistant A. baumannii in two comprehensive hospitals of Beijing, China. Front Microbiol 2015; 6:997. [PMID: 26441924 PMCID: PMC4585070 DOI: 10.3389/fmicb.2015.00997] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 09/07/2015] [Indexed: 12/21/2022] Open
Abstract
Acinetobacter baumannii is an important opportunistic pathogen associated with a variety of nosocomial infections. A rapid and sensitive molecular detection in clinical isolates is quite needed for the appropriate therapy and outbreak control of A. baumannii. Group 2 carbapenems have been considered the agents of choice for the treatment of multiple drug-resistant A. baumannii. But the prevalence of carbapenem-resistant A. baumannii (CRAB) has been steadily increasing in recent years. Here, we developed a loop-mediated isothermal amplification (LAMP) assay for the rapid detection of A. baumannii in clinical samples by using high-specificity primers of the bla OXA-51 gene. Then we investigated the OXA-carbapenemases molecular epidemiology of A. baumannii isolates in two comprehensive hospitals in Beijing. The results showed that the LAMP assay could detect target DNA within 60 min at 65°C. The detection limit was 50 pg/μl, which was about 10-fold greater than that of PCR. Furthermore, this method could distinguish A. baumannii from the homologous A. nosocomialis and A. pittii. A total of 228 positive isolates were identified by this LAMP-based method for A. baumannii from 335 intensive care unit patients with clinically suspected multi-resistant infections in two hospitals in Beijing. The rates of CRAB are on the rise and are slowly becoming a routine phenotype for A. baumannii. Among the CRABs, 92.3% harbored both the bla OXA-23 and bla OXA-51 genes. Thirty-three pulsotypes were identified by pulsed-field gel electrophoresis, and the majority belonged to clone C. In conclusion, the LAMP method developed for detecting A. baumannii was faster and simpler than conventional PCR and has great potential for both point-of-care testing and basic research. We further demonstrated a high distribution of class D carbapenemase-encoding genes, mainly OXA-23, which presents an emerging threat in hospitals in China.
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Affiliation(s)
- Puyuan Li
- Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China
| | - Wenkai Niu
- Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China
| | - Huan Li
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Hong Lei
- Department of Clinical Laboratory, 309th Hospital of Chinese People's Liberation Army Beijing, China
| | - Wei Liu
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Xiangna Zhao
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Leijing Guo
- Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China
| | - Dayang Zou
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Xin Yuan
- Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China
| | - Huiying Liu
- Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China
| | - Jing Yuan
- Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Changqing Bai
- Department of Respiratory and Critical Care Diseases, 307th Hospital of Chinese People's Liberation Army Beijing, China
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Chang Y, Luan G, Xu Y, Wang Y, Shen M, Zhang C, Zheng W, Huang J, Yang J, Jia X, Ling B. Characterization of carbapenem-resistant Acinetobacter baumannii isolates in a Chinese teaching hospital. Front Microbiol 2015; 6:910. [PMID: 26388854 PMCID: PMC4555021 DOI: 10.3389/fmicb.2015.00910] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 08/19/2015] [Indexed: 01/02/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) presents a serious therapeutic and infection control challenge. In this study, we investigated the epidemiological and molecular differences of CRAB and the threatening factors for contributing to increased CRAB infections at a hospital in western China. A total of 110 clinical isolates of A. baumannii, collected in a recent 2-year period, were tested for carbapenem antibiotic susceptibility, followed by a molecular analysis of carbapenemase genes. Genetic relatedness of the isolates was characterized by multilocus sequence typing. Sixty-seven of the 110 isolates (60.9%) were resistant to carbapenems, 80.60% (54/67) of which carried the blaOXA-23 gene. Most of these CRAB isolates (77.62%) were classified as clone complex 92 (CC92), and sequence type (ST) 92 was the most prevalent STs, followed by ST195, ST136, ST843, and ST75. One CRAB isolate of ST195 harbored plasmid pAB52 from a Chinese patient without travel history. This plasmid contains toxin–antitoxin elements related to adaptation for growth, which might have emerged as a common vehicle indirectly mediating the spread of OXA-23 in CRAB. Thus, CC92 A. baumannii carrying OXA-23 is a major drug-resistant strain spreading in China. Our findings indicate that rational application of antibiotics is indispensable for minimizing widespread of drug resistance.
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Affiliation(s)
- Yaowen Chang
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
| | - Guangxin Luan
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Ying Xu
- Clinical Laboratory, The First Affiliated Hospital, Chengdu Medical College Chengdu, China
| | - Yanhong Wang
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Min Shen
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Chi Zhang
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
| | - Wei Zheng
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
| | - Jinwei Huang
- Institute of Antibiotics, The Fifth Affiliated Hospital, Wenzhou Medical University Lishui, China
| | - Jingni Yang
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Xu Jia
- Non-coding RNA and Drug Discovery Laboratory, Chengdu Medical College Chengdu, China
| | - Baodong Ling
- Small Molecule Drugs Sichuan Key Laboratory, Institute of Materia Medica, Chengdu Medical College Chengdu, China
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Tiwari V, Roy R, Tiwari M. Antimicrobial active herbal compounds against Acinetobacter baumannii and other pathogens. Front Microbiol 2015; 6:618. [PMID: 26150810 PMCID: PMC4471432 DOI: 10.3389/fmicb.2015.00618] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 06/03/2015] [Indexed: 11/27/2022] Open
Abstract
Bacterial pathogens cause a number of lethal diseases. Opportunistic bacterial pathogens grouped into ESKAPE pathogens that are linked to the high degree of morbidity, mortality and increased costs as described by Infectious Disease Society of America. Acinetobacter baumannii is one of the ESKAPE pathogens which cause respiratory infection, pneumonia and urinary tract infections. The prevalence of this pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source and resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. The high level of acquired and intrinsic carbapenem resistance mechanisms acquired by these bacteria makes their eradication difficult. The pharmaceutical industry has no solution to this problem. Hence, it is an urgent requirement to find a suitable alternative to carbapenem, a commonly prescribed drug for Acinetobacter infection. In order to do this, here we have made an effort to review the active compounds of plants that have potent antibacterial activity against many bacteria including carbapenem resistant strain of A. baumannii. We have also briefly highlighted the separation and identification methods used for these active compounds. This review will help researchers involved in the screening of herbal active compounds that might act as a replacement for carbapenem.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of Rajasthan Ajmer, India
| | - Ranita Roy
- Department of Biochemistry, Central University of Rajasthan Ajmer, India
| | - Monalisa Tiwari
- Department of Biochemistry, Central University of Rajasthan Ajmer, India
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Saranathan R, Vasanth V, Vasanth T, Shabareesh PRV, Shashikala P, Devi CS, Kalaivani R, Asir J, Sudhakar P, Prashanth K. Emergence of carbapenem non-susceptible multidrug resistantAcinetobacter baumanniistrains of clonal complexes 103Band 92Bharboring OXA-type carbapenemases and metallo-β-lactamases in Southern India. Microbiol Immunol 2015; 59:277-84. [DOI: 10.1111/1348-0421.12252] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 01/13/2015] [Accepted: 02/23/2015] [Indexed: 11/27/2022]
Affiliation(s)
| | | | - Thamodharan Vasanth
- Department of Biotechnology; School of Life Sciences; Pondicherry University
| | | | - P. Shashikala
- Department of Clinical Microbiology; Pondicherry Institute of Medical Sciences; Pondicherry India
| | - Chandrakesan Sheela Devi
- Department of Clinical Microbiology; Pondicherry Institute of Medical Sciences; Pondicherry India
| | - Ramakrishnan Kalaivani
- Department of Clinical Microbiology; Pondicherry Institute of Medical Sciences; Pondicherry India
| | - Johny Asir
- Department of Clinical Microbiology; Pondicherry Institute of Medical Sciences; Pondicherry India
| | - Pagal Sudhakar
- Department of Biotechnology; School of Life Sciences; Pondicherry University
| | - K Prashanth
- Department of Biotechnology; School of Life Sciences; Pondicherry University
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Kuo SC, Lee YT, Yang Lauderdale TL, Huang WC, Chuang MF, Chen CP, Su SC, Lee KR, Chen TL. Contribution of Acinetobacter-derived cephalosporinase-30 to sulbactam resistance in Acinetobacter baumannii. Front Microbiol 2015; 6:231. [PMID: 26284030 PMCID: PMC4517069 DOI: 10.3389/fmicb.2015.00231] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Accepted: 03/09/2015] [Indexed: 11/13/2022] Open
Abstract
The sulbactam resistance rate in Acinetobacter baumannii has increased worldwide. Previous reports have shown that the β-lactamase blaTEM-1 confers resistance to sulbactam in A. baumannii. The purpose of this study was to examine whether other β-lactamases, including the Acinetobacter-derived cephalosporinase (ADC), OXA-23, OXA-24/72, and OXA-58 families, also contribute to sulbactam resistance in A. baumannii. The correlation between these β-lactamases and the sulbactam minimal inhibitory concentration (MIC) was determined using A. baumannii clinical isolates from diverse clonality, which were collected in a nationwide surveillance program from 2002 to 2010 in Taiwan. A possible association between the genetic structure of ISAba1-blaADC-30 and sulbactam resistance was observed because this genetic structure was detected in 97% of sulbactam-resistant strains compared with 10% of sulbactam-susceptible strains. Transformation of ISAba1-blaADC-30 into susceptible strains increased the sulbactam MIC from 2 to 32 μg/ml, which required blaADC-30 overexpression using an upstream promoter in ISAba1. Flow cytometry showed that ADC-30 production increased in response to sulbactam, ticarcillin, and ceftazidime treatment. This effect was regulated at the RNA level but not by an increase in the blaADC-30 gene copy number as indicated by quantitative PCR. Purified ADC-30 decreased the inhibitory zone created by sulbactam or ceftazidime, similarly to TEM-1. In conclusion, ADC-30 overexpression conferred resistance to sulbactam in diverse clinical A. baumannii isolates.
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Affiliation(s)
- Shu-Chen Kuo
- Institute of Clinical Medicine, Schsool of Medicine, National Yang-Ming University Taipei, Taiwan ; National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes Taipei, Taiwan ; Division of Infectious Diseases, Taipei Veterans General Hospital Taipei, Taiwan
| | - Yi-Tzu Lee
- Institute of Clinical Medicine, Schsool of Medicine, National Yang-Ming University Taipei, Taiwan ; Emergency Department, Taipei Veterans General Hospital Taipei, Taiwan
| | - Tsai-Ling Yang Lauderdale
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes Taipei, Taiwan
| | - Wei-Cheng Huang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes Taipei, Taiwan
| | - Ming-Fen Chuang
- Division of Infectious Diseases, Taipei Veterans General Hospital Taipei, Taiwan
| | - Chien-Pei Chen
- Division of Infectious Diseases, Taipei Veterans General Hospital Taipei, Taiwan
| | - Shey-Chiang Su
- Department of Internal Medicine, Mackay Memorial Hospital Hsin-Chu, Taiwan
| | - Kuan-Rong Lee
- Department of Molecular Medicine and Institute of Life Science, National Tsing Hua University Hsin-Chu, Taiwan
| | - Te-Li Chen
- Institute of Clinical Medicine, Schsool of Medicine, National Yang-Ming University Taipei, Taiwan ; Division of Infectious Diseases, Taipei Veterans General Hospital Taipei, Taiwan
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Tiwari V, Tiwari M. Quantitative proteomics to study carbapenem resistance in Acinetobacter baumannii. Front Microbiol 2014; 5:512. [PMID: 25309531 PMCID: PMC4176082 DOI: 10.3389/fmicb.2014.00512] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/11/2014] [Indexed: 12/28/2022] Open
Abstract
Acinetobacter baumannii is an opportunistic pathogen causing pneumonia, respiratory infections and urinary tract infections. The prevalence of this lethal pathogen increases gradually in the clinical setup where it can grow on artificial surfaces, utilize ethanol as a carbon source. Moreover it resists desiccation. Carbapenems, a β-lactam, are the most commonly prescribed drugs against A. baumannii. Resistance against carbapenem has emerged in Acinetobacter baumannii which can create significant health problems and is responsible for high morbidity and mortality. With the development of quantitative proteomics, a considerable progress has been made in the study of carbapenem resistance of Acinetobacter baumannii. Recent updates showed that quantitative proteomics has now emerged as an important tool to understand the carbapenem resistance mechanism in Acinetobacter baumannii. Present review also highlights the complementary nature of different quantitative proteomic methods used to study carbapenem resistance and suggests to combine multiple proteomic methods for understanding the response to antibiotics by Acinetobacter baumannii.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, Central University of RajasthanAjmer, India
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Phosphoproteomics as an emerging weapon to develop new antibiotics against carbapenem resistant strain of Acinetobacter baumannii. J Proteomics 2014; 112:336-8. [PMID: 25252118 DOI: 10.1016/j.jprot.2014.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 08/30/2014] [Accepted: 09/02/2014] [Indexed: 01/05/2023]
Abstract
Acinetobacter baumannii causes pneumonia, bloodstream infections, urinary tract infections, respiratory infections and meningitis. A. baumannii has developed resistance against most of the antibiotics including carbapenem. Therefore, to battle carbapenem resistance, there is a need to develop antimicrobial drugs with new modes of action. Phosphoproteomics will help identify the differentially phosphorylated protein and its crucial phosphosites which facilitate the elucidation of molecular mechanism of signaling and regulation of carbapenem resistant strain of A. baumannii as compared to carbapenem sensitive strain. This understanding might be useful for the development of new antibiotics against kinases involved in the phosphorylation of identified phosphosites in carbapenem resistant strain of A. baumannii. The proposed antibiotics selectively inhibit carbapenem resistant strain which further avoids its excessive use against carbapenem sensitive strain and thereafter reduces emergence of resistance.
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Perween N, Sehgal S, Prakash SK. Geographical patterns in antimicrobial resistance of acinetobacter in clinical isolates. J Clin Diagn Res 2014; 8:DC10-2. [PMID: 24959441 DOI: 10.7860/jcdr/2014/8590.4235] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/26/2014] [Indexed: 12/20/2022]
Abstract
OBJECTIVES Acinetobacter spp. has emerged as a threat to the healthcare workers throughout the globe, owing to its property of multidrug resistance. The aim of the present study was to evaluate the antimicrobial resistance patterns of Acinetobacter spp. among indoor and out patients in our hospital and compare the resistance patterns in India and abroad. MATERIALS AND METHODS In this retrospective study, which was carried out between Over a period of one year, a total of 5593 clinical specimens of pus and purulent fluids were examined and antimicrobial resistance pattern for Acinetobacter spp. using Modified Stoke's were evaluated. Also a comparison was done with the other similar studies. STATISTICAL ANALYSIS Using the proportions of sensitive and resistant, the statistical analysis was done. The total, mean and percentage were calculated by using SPSS. RESULTS A high level of antimicrobial multidrug-resistance was found in almost all the clinical isolate. Our study was also found to be concordant with the results of other studies. CONCLUSION There is an emerging need for identification of the genes and mechanisms for multidrug resistance among Acinetobacter spp.
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Affiliation(s)
- Naz Perween
- Senior Resident, Department of Microbiology, Maulana Azad Medical College , New Delhi, India
| | - Sonal Sehgal
- Post Graduate Student,Department of Microbiology, Maulana Azad Medical College , New Delhi, India
| | - S Krishna Prakash
- Director Professor, Department of Microbiology, Maulana Azad Medical College , New Delhi, India
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Tiwari V, Moganty RR. Conformational stability of OXA-51 β-lactamase explains its role in carbapenem resistance of Acinetobacter baumannii. J Biomol Struct Dyn 2013; 32:1406-20. [PMID: 23879430 DOI: 10.1080/07391102.2013.819789] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Acinetobacter baumannii, an important nosocomial pathogen, is increasingly becoming resistant to antibiotics including recent β-lactam like imipenem. Production of different types of β-lactamases is one of the major resistance mechanisms which bacteria adapt. We recently reported the presence of a β-lactamase, OXA-51, in clinical strains of A. baumannii in ICUs of our hospital. This study is an attempt to understand the structure-function relationship of purified OXA-51 in carbapenem resistance in A. baumannii. The OXA-51 was cloned, expressed in E. coli Bl-21(DE3) and further purified. The in vitro enzyme activity of purified OXA-51 was confirmed by two independent techniques; in-gel assay and spectrophotometric method using nitrocefin. Further in vivo effect of OXA-51 was followed by transmission electron microscopy of bacterium. Biophysical and biochemical investigations of OXA-51 were done using LC-MS/MS, UV-Vis absorption, fluorescence, circular dichroic spectroscopy and isothermal calorimetry. Native OXA-51 was characterized as 30.6 kDa, pI 8.43 with no disulphide bonds and comprising of 30% α-helix, 27% β-sheet. Secondary structure of OXA-51 was significantly unchanged in broad pH (4-10) and temperature (30-60 °C) range with only local alterations at tertiary structural level. Interestingly, enzymatic activity up to 75% was retained under above conditions. Hydrolysis of imipenem by OXA-51 (k(m),1 μM) was found to be thermodynamically favourable. In the presence of imipenem, morphology of sensitive strain of A. baumannii was drastically changed, while OXA-51-transformed sensitive strain retained the stable coccobacillus shape, which demonstrates that imipenem is able to kill sensitive strain but is unable to do so in OXA-51-transformed strain. Hence the production of pH- and temperature-stable OXA-51 appears to be a major determinant in the resistance mechanisms adopted by A. baumannii in order to evade even the latest β-lactams, imipenem. It can be concluded from the study that OXA-51 plays a vital role in the survival of the pathogen under stress conditions and thus poses a major threat.
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Affiliation(s)
- Vishvanath Tiwari
- a Department of Biochemistry , All India Institute of Medical Sciences , Ansari Nagar, New Delhi 110029 , India
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Tiwari V, Moganty RR. Structural studies on New Delhi Metallo-β-lactamase (NDM-2) suggest old β-lactam, penicillin to be better antibiotic for NDM-2-harbouring Acinetobacter baumanni. J Biomol Struct Dyn 2012; 31:591-601. [PMID: 22888760 DOI: 10.1080/07391102.2012.706075] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Acinetobacter baumannii, a Gram-negative pathogen causes nosocomial infections including pneumonia, urinary tract and respiratory infections. Carbapenem group of β-lactam antibiotics are routinely used to treat A. baumannii including multidrug-resistant clinical strains. The emergence of New Delhi Metallo-β-lactamase (NDM-2), a new type of β-lactamase and one of the major resistant determinants in A. baumannii, opened up challenges in the treatment of resistant strains. Thus, understanding the structure-function relationship of NDM-2 with different analogues of β-lactams becomes crucial. We carried out in silico studies on the interaction of various β-lactams with NDM-2 and with OXA-24, a carbapenem hydrolyzing non-NDM type β-lactamase. The binding affinity of the β-lactams to NDM-2 was found to be in the order: ceftazidime ≈ imipenem ≈ doripenem > oxacillin > aztreonam > penicillin; however, the order of their affinity to OXA-24 was quite different: ceftazidime > aztreonam > penicillin > oxacillin > doripenem > imipenem. Further, NDM-2 in comparison to OXA-24 showed stronger interaction (less X-score) with most of the β-lactams except penicillin. This suggests higher lethality posed by clinical strains expressing NDM-2 than those without NDM-2. Weak interaction between NDM-2 and penicillin clearly points out that penicillin is perhaps better option in treating A. baumannii harbouring NDM-2. Present findings provide new insights in drug resistance at the molecular level of NDM-2 and can help in designing structure-based drugs.
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Affiliation(s)
- Vishvanath Tiwari
- All India Institute of Medical Sciences, Department of Biochemistry, Ansari Nagar, New Delhi, 110029, India
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Tiwari V, Vashistt J, Kapil A, Moganty RR. Comparative proteomics of inner membrane fraction from carbapenem-resistant Acinetobacter baumannii with a reference strain. PLoS One 2012; 7:e39451. [PMID: 22761799 PMCID: PMC3383706 DOI: 10.1371/journal.pone.0039451] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 05/21/2012] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii has been identified by the Infectious Diseases Society of America as one of the six pathogens that cause majority of hospital infections. Increased resistance of A.baumannii even to the latest generation of β-lactams like carbapenem is an immediate threat to mankind. As inner-membrane fraction plays a significant role in survival of A.baumannii, we investigated the inner-membrane fraction proteome of carbapenem-resistant strain of A.baumannii using Differential In-Gel Electrophoresis (DIGE) followed by DeCyder, Progenesis and LC-MS/MS analysis. We identified 19 over-expressed and 4 down-regulated proteins (fold change>2, p<0.05) in resistant strain as compared to reference strain. Some of the upregulated proteins in resistant strain and their association with carbapenem resistance in A.baumannii are: i) β-lactamases, AmpC and OXA-51: cleave and inactivate carbapenem ii) metabolic enzymes, ATP synthase, malate dehydrogenase and 2-oxoglutarate dehydrogenase: help in increased energy production for the survival and iii) elongation factor Tu and ribosomal proteins: help in the overall protein production. Further, entry of carbapenem perhaps is limited by controlled production of OmpW and low levels of surface antigen help to evade host defence mechanism in developing resistance in A.baumannii. Present results support a model for the importance of proteins of inner-membrane fraction and their synergistic effect in the mediation of resistance of A.baumannii to carbapenem.
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Affiliation(s)
- Vishvanath Tiwari
- Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Jitendraa Vashistt
- Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Arti Kapil
- Department of Microbiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Rajeswari R. Moganty
- Department of Biochemistry, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
- * E-mail:
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