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Hu L, Zhang XT, Zeng X, Xiong LX, Ai Q, Liu CJ, Yang WW, Wu Y, Guo X, Li GQ, Liu L. ISAba1-mediated intrinsic chromosomal oxacillinase amplification confers carbapenem resistance in Acinetobacter baumannii. Int J Antimicrob Agents 2024; 64:107258. [PMID: 38914142 DOI: 10.1016/j.ijantimicag.2024.107258] [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: 06/25/2023] [Revised: 05/19/2024] [Accepted: 06/17/2024] [Indexed: 06/26/2024]
Abstract
Tandem amplification of carbapenemase genes increases gene copy number and enhances carbapenem resistance. These amplifications are often heterogeneous, transient, and located on plasmids, which also contribute to heteroresistance. Amplification of encoding genes is especially important for enzymes with low hydrolysis activity, which are often overlooked. Here, we reported an intrinsic oxacillinase oxaAb amplification flanked by ISAba1. The amplification is in the chromosome and contains up to 25 repeats. We provided genomic, transcriptomic, and proteomic evidence that the amplification resulted in oxacillinase overproduction. Notably, no point mutations of oxaAb were found during the amplification process. Strains of Acinetobacter baumannii with intrinsic amplified or external transformed ISAba1-oxaAb exhibited higher meropenem hydrolysis activity. Furthermore, the number of repeats in the amplification decreased gradually over a period of 21 d cultured with carbapenem withdrawal. However, upon re-exposure to meropenem, the ISAba1 flanked oxaAb responded rapidly, with repeat numbers reaching or exceeding pre-carbapenem withdrawal levels within 24 h. Taken together, these findings suggest that ISAba1-mediated gene amplification and overproduction of intrinsic low-activity oxacillinase oxaAb resulted in carbapenem resistance.
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Affiliation(s)
- Limiao Hu
- Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Xiao-Tuan Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xi Zeng
- Department of Gastroenterology, The First Affiliated Hospital of Shaoyang University, Shaoyang, China
| | - Lu-Xi Xiong
- Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Qi Ai
- Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Cai-Juan Liu
- Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Wei-Wei Yang
- Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China
| | - Yuan Wu
- Department of Clinical Laboratory Medicine, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China.
| | - Xuemin Guo
- Meizhou People's Hospital, Meizhou, China; Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China.
| | - Guo-Qing Li
- Department of Gastroenterology, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China; Hunan Provincial Key Laboratory of Basic and Clinical Pharmacological Research for Gastroenterological Tumors, Hengyang, China.
| | - Logen Liu
- Hunan Provincial Key Laboratory of Basic and Clinical Pharmacological Research for Gastroenterological Tumors, Hengyang, China; Clinical Research Center, The Second Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, China.
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2
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Rajangam SL, Narasimhan MK. Current treatment strategies for targeting virulence factors and biofilm formation in Acinetobacter baumannii. Future Microbiol 2024; 19:941-961. [PMID: 38683166 PMCID: PMC11290764 DOI: 10.2217/fmb-2023-0263] [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: 11/24/2023] [Accepted: 03/20/2024] [Indexed: 05/01/2024] Open
Abstract
A higher prevalence of Acinetobacter baumannii infections and mortality rate has been reported recently in hospital-acquired infections (HAI). The biofilm-forming capability of A. baumannii makes it an extremely dangerous pathogen, especially in device-associated hospital-acquired infections (DA-HAI), thereby it resists the penetration of antibiotics. Further, the transmission of the SARS-CoV-2 virus was exacerbated in DA-HAI during the epidemic. This review specifically examines the complex interconnections between several components and genes that play a role in the biofilm formation and the development of infections. The current review provides insights into innovative treatments and therapeutic approaches to combat A. baumannii biofilm-related infections, thereby ultimately improving patient outcomes and reducing the burden of HAI.
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Affiliation(s)
- Seetha Lakshmi Rajangam
- Department of Genetic Engineering, School of Bioengineering, College of Engineering & Technology, SRM Institute of Science & Technology, Kattankulathur, Chennai, Tamil Nadu, 603203, India
| | - Manoj Kumar Narasimhan
- Department of Genetic Engineering, School of Bioengineering, College of Engineering & Technology, SRM Institute of Science & Technology, Kattankulathur, Chennai, Tamil Nadu, 603203, India
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Geng J, Liu H, Chen S, Long J, Jin Y, Yang H, Duan G. Comparative genomic analysis of Escherichia coli strains obtained from continuous imipenem stress evolution. FEMS Microbiol Lett 2022; 369:6526866. [PMID: 35147175 DOI: 10.1093/femsle/fnac015] [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: 11/02/2021] [Revised: 01/07/2022] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
The carbapenem-resistant Escherichia coli (E. coli) has aroused increasing attention worldwide, especially in terms of imipenem (IMP) resistance. The molecular mechanism of IMP resistance remains unclear. This study aimed to explore the resistance mechanisms of IMP in E. coli. Susceptible Sx181-0-1 strain was induced into resistance strains by adaptive laboratory evolution. The drug resistance spectrum was measured using the disk diffusion and microbroth dilution methods. Whole-genome sequencing and resequencing were used to analyze the non-synonymous single-nucleotide polymorphisms (nsSNPs) between the primary susceptible strain and resistant strains. The expression levels of these genes with nsSNPs were identified by real-time quantitative PCR (RT-qPCR). Resistance phenotype appeared in the induced 15th generation (induction time = 183 h). Sx181-32 and Sx181-256, which had minimum inhibitory concentrations of IMP of 8 and 64 µg mL-1, were isolated during continuous subculture exposed to increasing concentrations of IMP, respectively. Nineteen nsSNPs were observed both in Sx181-32 and Sx181-256, including rpsU, sdaC, zwf, ttuC, araJ, dacC, mrdA, secF, dacD, lpxD, mrcB, ftsI, envZ, and two unknown function genes (orf01892 and orf01933). Among these 15 genes, five genes (dacC, mrdA, lpxD, mrcB, and ftsI) were mainly involved in cell wall synthesis. The mrdA (V338A, L378P, and M574I) and mrcB (P784L, A736V, and T708A) had three amino acid substitutions, respectively. The expression levels of rpsU, ttuC and orf01933 were elevated in both Sx181-32 and Sx181-256 compared to Sx181-0-1. The expression levels of these genes were elevated in Sx181-256, except for araJ. Bacteria developed resistance to antimicrobials by regulating various biological processes, among which the most involved is the cell wall synthesis (dacC, mrdA, lpxD, mrcB, and ftsI). The combination mutations of mrdA, envZ, and ftsI genes may increase the resistance to IMP. Our study could improve the understanding of the molecular mechanism underlying the IMP resistance of E. coli.
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Affiliation(s)
- Juan Geng
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Huiying Liu
- People's Hospital of Henan University of Chinese Medicine, Zhengzhou, China.,People's Hospital of Zhengzhou, Zhengzhou, China
| | - Shuaiyin Chen
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Jinzhao Long
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Yuefei Jin
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Haiyan Yang
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
| | - Guangcai Duan
- Department of Epidemiology and Health Statistics, College of Public Health, Zhengzhou University, Zhengzhou, China
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Alrahmany D, Omar AF, Harb G, El Nekidy WS, Ghazi IM. Acinetobacter baumannii Infections in Hospitalized Patients, Treatment Outcomes. Antibiotics (Basel) 2021; 10:antibiotics10060630. [PMID: 34070398 PMCID: PMC8229601 DOI: 10.3390/antibiotics10060630] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 05/18/2021] [Accepted: 05/21/2021] [Indexed: 12/04/2022] Open
Abstract
Background Acinetobacter baumannii (AB), an opportunistic pathogen, could develop into serious infections with high mortality and financial burden. The debate surrounding the selection of effective antibiotic treatment necessitates studies to define the optimal approach. This study aims to compare the clinical outcomes of commonly used treatment regimens in hospitalized patients with AB infections to guide stewardship efforts. Material and methods: Ethical approval was obtained, 320 adult patients with confirmed AB infections admitted to our tertiary care facility within two years were enrolled. The treatment outcomes were statistically analyzed to study the relation between antibiotic regimens and 14, 28, and 90-day mortality as the primary outcomes using binary logistic regression—using R software—in addition to the length of hospitalization, adverse events due to antibiotic treatment, and 90-day recurrence as secondary outcomes. Results: Among 320 patients, 142 (44%) had respiratory tract, 105 (33%) soft tissue, 42 (13%) urinary tract, 22 (7%) bacte iemia, and other infections 9 (3%). Nosocomial infections were 190 (59%) versus community-acquired. Monotherapy was significantly associated with lower 28-day (p < 0.05, OR:0.6] and 90-day (p < 0.05, OR:0.4) mortality rates, shorter length of stay LOS (p < 0.05, Median: −12 days] and limited development of adverse events (p < 0.05, OR:0.4). Subgroup analysis revealed similar results ranging from lower odds of mortality, adverse events, and shorter LOS to statistically significant correlation to monotherapy. Meropenem (MEM) and piperacillin/tazobactam (PIP/TAZ) monotherapies showed non-significant high odd ratios of mortalities, adverse events, and disparate LOS. There was a statistical correlation between most combined therapies and adverse events, and longer LOS. Colistin based and colistin/meropenem (CST/MEM) combinations were superior in terms of 14-day mortality (p = 0.05, OR:0.4) and (p < 0.05, OR:0.4) respectively. Pip/Taz and MEM-based combined therapies were associated with statistically non-significant high odd ratios of mortalities. Tigecycline (TGC)-based combinations showed a significant correlation to mortalities (p < 0.05, OR:2.5). Conclusion: Monotherapy was associated with lower mortality rates, shorter LOS, and limited development of adverse events compared to combined therapies. Colistin monotherapy, colistin/meropenem, and other colistin combinations showed almost equivalent mortality outcomes. Patients on combined therapy were more susceptible to adverse events and comparable LOS. The possible adverse outcomes of PIP/TAZ and MEM-based therapies in the treatment of MDRAB infections and the association of TGC with a higher mortality rate raise doubts about their treatment role.
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Affiliation(s)
| | - Ahmed F. Omar
- General Medicine Department, Sohar Hospital, Sohar 311, Oman;
| | - Gehan Harb
- Gehan Harb Statistics, Cairo 11511, Egypt;
| | - Wasim S. El Nekidy
- Cleveland Clinic Abu Dhabi, Abu-Dhabi P.O. Box 112412, United Arab Emirates;
- Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH 44195, USA
| | - Islam M. Ghazi
- Philadelphia College of Pharmacy, University of the Sciences, Philadelphia, PA 19104, USA
- Correspondence: ; Tel.: +1-215-596-7121; Fax: +1-215-596-8586
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Zhang L, Fu Y, Han X, Xu Q, Weng S, Yan B, Liu L, Hua X, Chen Y, Yu Y. Phenotypic Variation and Carbapenem Resistance Potential in OXA-499-Producing Acinetobacter pittii. Front Microbiol 2020; 11:1134. [PMID: 32582088 PMCID: PMC7296048 DOI: 10.3389/fmicb.2020.01134] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 05/05/2020] [Indexed: 12/17/2022] Open
Abstract
Acinetobacter pittii is increasingly recognized as a clinically important species. Here, we identified a carbapenem-non-resistant A. pittii clinical isolate, A1254, harboring blaOXA–499, blaOXA–826, and blaADC–221. The blaOXA–499 genetic environment in A1254 was identical to that of another OXA-499-producing, but carbapenem-resistant, A. pittii isolate, YMC2010/8/T346, indicating the existence of phenotypic variation among OXA-499-producing A. pittii strains. Under imipenem-selective pressure, the A1254 isolate developed resistance to carbapenems in 60 generations. Two carbapenem-resistant mutants (CAB009 and CAB010) with mutations in the blaOXA–499 promoter region were isolated from two independently evolved populations (CAB001 and CAB004). The CAB009 mutant, with a mutation at position −14 (A to G), exhibited a four-fold higher carbapenem minimum inhibitory concentration (MIC) and a 4.53 ± 0.19 log2 fold change higher expression level of blaOXA–499 than the ancestor strain, A1254. The other mutant, CAB010, with a mutation at position −42 (G to A), showed a two-fold higher carbapenem MIC and a 1.65 ± 0.25 log2 fold change higher blaOXA–499 expression level than the ancestor strain. The blaOXA–499 gene and its promoter region were amplified from the wild-type strain and two mutant isolates and then individually cloned into the pYMAb2-Hygr vector and expressed in Acinetobacter baumannii ATCC 17978, A. pittii LMG 1035, and A. pittii A1254. All the transformed strains were resistant to carbapenem, irrespective of whether they harbored the initial or an evolved promoter sequence, and transformed strains expressing the promoter from the most resistant mutant, CAB009, showed the highest carbapenem MICs, with values of 32–64 μg/ml for imipenem and 128 μg/ml for meropenem. RNA sequencing was performed to confirm the contribution of blaOXA–499 to the development of carbapenem resistance. Although the CAB009 and CAB010 transcriptional patterns were different, blaOXA–499 was the only differentially expressed gene shared by the two mutants. Our results indicate that carbapenem-non-resistant Acinetobacter spp. strains carrying blaOXA genes have the potential to develop carbapenem resistance and need to be further investigated and monitored to prevent treatment failure due to the development of resistance.
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Affiliation(s)
- Linyue Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Ying Fu
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China.,Department of Clinical Laboratory, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Xinhong Han
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Qingye Xu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Shanshan Weng
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Biyong Yan
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lilin Liu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
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Kesavan D, Vasudevan A, Wu L, Chen J, Su Z, Wang S, Xu H. Integrative analysis of outer membrane vesicles proteomics and whole-cell transcriptome analysis of eravacycline induced Acinetobacter baumannii strains. BMC Microbiol 2020; 20:31. [PMID: 32046644 PMCID: PMC7014627 DOI: 10.1186/s12866-020-1722-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/06/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Acinetobacter baumannii is a multidrug-resistant (MDR) hazardous bacterium with very high antimicrobial resistance profiles. Outer membrane vesicles (OMVs) help directly and/or indirectly towards antibiotic resistance in these organisms. The present study aims to look on the proteomic profile of OMV as well as on the bacterial transcriptome upon exposure and induction with eravacycline, a new synthetic fluorocycline. RNA sequencing analysis of whole-cell and LC-MS/MS proteomic profiling of OMV proteome abundance were done to identify the differential expression among the eravacycline-induced A. baumannii ATCC 19606 and A. baumannii clinical strain JU0126. RESULTS The differentially expressed genes from the RNA sequencing were analysed using R package and bioinformatics software and tools. Genes encoding drug efflux and membrane transport were upregulated among the DEGs from both ATCC 19606 and JU0126 strains. As evident with the induction of eravacycline resistance, ribosomal proteins were upregulated in both the strains in the transcriptome profiles and also resistance pumps, such as MFS, RND, MATE and ABC transporters. High expression of stress and survival proteins were predominant in the OMVs proteome with ribosomal proteins, chaperons, OMPs OmpA, Omp38 upregulated in ATCC 19606 strain and ribosomal proteins, toluene tolerance protein, siderophore receptor and peptidases in the JU0126 strain. The induction of resistance to eravacycline was supported by the presence of upregulation of ribosomal proteins, resistance-conferring factors and stress proteins in both the strains of A. baumannii ATCC 19606 and JU0126, with the whole-cell gene transcriptome towards both resistance and stress genes while the OMVs proteome enriched more with survival proteins. CONCLUSION The induction of resistance to eravacycline in the strains were evident with the increased expression of ribosomal and transcription related genes/proteins. Apart from this resistance-conferring efflux pumps, outer membrane proteins and stress-related proteins were also an essential part of the upregulated DEGs. However, the expression profiles of OMVs proteome in the study was independent with respect to the whole-cell RNA expression profiles with low to no correlation. This indicates the possible role of OMVs to be more of back-up additional protection to the existing bacterial cell defence during the antibacterial stress.
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Affiliation(s)
- DineshKumar Kesavan
- International Genomics Research Centre (IGRC), Jiangsu University, Zhenjiang, 212013, China.,Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Aparna Vasudevan
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Liang Wu
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Jianguo Chen
- Department of Laboratory Medicine, The Affiliated People's Hospital, Jiangsu University, Zhenjiang, 212001, China
| | - Zhaoliang Su
- International Genomics Research Centre (IGRC), Jiangsu University, Zhenjiang, 212013, China.,Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Shengjun Wang
- Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China
| | - Huaxi Xu
- International Genomics Research Centre (IGRC), Jiangsu University, Zhenjiang, 212013, China. .,Department of Immunology, School of Medicine, Jiangsu University, Zhenjiang, 212013, China.
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Gao Q, Meng X, Gu H, Chen X, Yang H, Qiao Y, Guo X. Two Phenotype-Differentiated Acinetobacter baumannii Mutants That Survived in a Meropenem Selection Display Large Differences in Their Transcription Profiles. Front Microbiol 2019; 10:2308. [PMID: 31649648 PMCID: PMC6794425 DOI: 10.3389/fmicb.2019.02308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 09/20/2019] [Indexed: 11/13/2022] Open
Abstract
37662RM1 and 37662RM2 are two phenotypically different, carbapenem-resistant mutants of Acinetobacter baumannii 37662 isolate following selection with meropenem (MEM) at sub-inhibitory concentrations. 37662RM2 lacks capsule synthesis and shows dramatically increased biofilm formation, while 37662RM1 shows merely impaired capsule synthesis. Here we report that 37662RM1 and RM2 have transcription profiles that are different from those of their starting strain, 37662WT. There were far more differentially expressed genes in 37662RM2 than in 37662RM1. The capsule polysaccharide (CPS) synthesis-required genes (itrA2, gtr5, psaA, psaB, psaC, psaD, psaE, psaF, kpsS2, wzx, wzy, wza, wzb, and wzc) showed reduced transcription levels in 37662RM2, which may at least partially explain the loss of capsule synthesis. The csu operon genes responsible for pili assembly and their regulator genes bfmR-bfmS were over-expressed in 37662RM2. This result together with the established critical roles of these genes in biofilm formation provide solid evidence that up-regulation of csu and bfmR-bfmS should be considered responsible for the enhanced biofilm formation in 37662RM2. ISAba1 was found to insert into the intergenic region between the csu operon and the acrR gene and should be responsible for the significant up-regulation of acrR, which was proposed to be associated with biofilm formation. Genome sequencing revealed that the ISAba1 upstream bla OXA- 508 (a new member of bla OXA- 51-like) and acrR were duplicated, suggesting a replicative transposition event. Altogether, the phenotype divergence driven by MEM selection mainly occurs at the RNA level and the transposition of ISAba1 plays an important role in modulating gene expression to adapt to the environment.
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Affiliation(s)
- Qianqian Gao
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xiaobin Meng
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China
| | - Hanfu Gu
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China
| | - Xueqin Chen
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China
| | - Huaqing Yang
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Yangyang Qiao
- Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
| | - Xuemin Guo
- Meizhou People's Hospital, Meizhou, China.,Guangdong Provincial Key Laboratory of Precision Medicine and Clinical Translation Research of Hakka Population, Meizhou, China.,Key Laboratory of Tropical Disease Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
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8
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Ušjak D, Ivković B, Božić DD, Bošković L, Milenković M. Antimicrobial activity of novel chalcones and modulation of virulence factors in hospital strains of Acinetobacter baumannii and Pseudomonas aeruginosa. Microb Pathog 2019; 131:186-196. [PMID: 30980878 DOI: 10.1016/j.micpath.2019.04.015] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 04/09/2019] [Accepted: 04/09/2019] [Indexed: 01/01/2023]
Abstract
Acinetobacter baumannii and Pseudomonas aeruginosa are frequent multiresistant nosocomial pathogens that cause wound and pulmonary infections in hospitalized patients. As being increasingly resistant to most clinically available antibiotics, there is a constant need for exploration of new substances that could kill them or inhibit their growth, or alternatively inhibit some of their essential virulence factors. Chalcones are chemical compounds with well-documented antimicrobial potential. The aim of this study was to examine effectiveness of four newly-synthesized chalcones against the multiresistant clinical strains of A. baumannii and P. aeruginosa. Antibacterial activity of chalcones was investigated with broth-microdilution test and time-dependent killing assay. Synergistic effects of tested compounds with antibiotics (meropenem, amikacin and ciprofloxacin) were determined by checkerboard assay. The effects of chalcones on expression of virulence factors in P. aeruginosa (pyocyanin production, swimming and swarming motility) and A. baumannii (twitching and surface-associated motility), along with their biofilm production, were also examined. The obtained results indicate substantial antimicrobial activity of the tested chalcones (MICs = 100-175 μg/mL) and several synergistic interactions with antibiotics, as well as notable reduction in expression of all investigated virulence factors. These promising results may constitute a good basis for further research.
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Affiliation(s)
- Dušan Ušjak
- Department of Microbiology and Immunology, University of Belgrade, Faculty of Pharmacy, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Branka Ivković
- Department of Pharmaceutical Chemistry, University of Belgrade, Faculty of Pharmacy, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Dragana D Božić
- Department of Microbiology and Immunology, University of Belgrade, Faculty of Pharmacy, Vojvode Stepe 450, 11221, Belgrade, Serbia
| | - Lidija Bošković
- Department of Laboratory Diagnostics, Clinical Hospital Centre "Dr. Dragiša Mišović", Heroja Milana Tepića 1, 11000, Belgrade, Serbia
| | - Marina Milenković
- Department of Microbiology and Immunology, University of Belgrade, Faculty of Pharmacy, Vojvode Stepe 450, 11221, Belgrade, Serbia.
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9
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Singh JK, Adams FG, Brown MH. Diversity and Function of Capsular Polysaccharide in Acinetobacter baumannii. Front Microbiol 2019; 9:3301. [PMID: 30687280 PMCID: PMC6333632 DOI: 10.3389/fmicb.2018.03301] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/18/2018] [Indexed: 11/30/2022] Open
Abstract
The Gram-negative opportunistic bacterium Acinetobacter baumannii is a significant cause of hospital-borne infections worldwide. Alarmingly, the rapid development of antimicrobial resistance coupled with the remarkable ability of isolates to persist on surfaces for extended periods of time has led to infiltration of A. baumannii into our healthcare environments. A major virulence determinant of A. baumannii is the presence of a capsule that surrounds the bacterial surface. This capsule is comprised of tightly packed repeating polysaccharide units which forms a barrier around the bacterial cell wall, providing protection from environmental pressures including desiccation and disinfection regimes as well as host immune responses such as serum complement. Additionally, capsule has been shown to confer resistance to a range of clinically relevant antimicrobial compounds. Distressingly, treatment options for A. baumannii infections are becoming increasingly limited, and the urgency to develop effective infection control strategies and therapies to combat infections is apparent. An increased understanding of the contribution of capsule to the pathobiology of A. baumannii is required to determine its feasibility as a target for new strategies to combat drug resistant infections. Significant variation in capsular polysaccharide structures between A. baumannii isolates has been identified, with over 100 distinct capsule types, incorporating a vast variety of sugars. This review examines the studies undertaken to elucidate capsule diversity and advance our understanding of the role of capsule in A. baumannii pathogenesis.
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Affiliation(s)
- Jennifer K Singh
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Felise G Adams
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
| | - Melissa H Brown
- College of Science and Engineering, Flinders University, Bedford Park, SA, Australia
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