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Maure A, Robino E, Van der Henst C. The intracellular life of Acinetobacter baumannii. Trends Microbiol 2023; 31:1238-1250. [PMID: 37487768 DOI: 10.1016/j.tim.2023.06.007] [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: 09/05/2022] [Revised: 06/16/2023] [Accepted: 06/23/2023] [Indexed: 07/26/2023]
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic bacterium responsible for nosocomial and community-acquired infections. This pathogen is globally disseminated and associated with high levels of antibiotic resistance, which makes it an important threat to human health. Recently, new evidence showed that several A. baumannii isolates can survive and proliferate within eukaryotic professional and/or nonprofessional phagocytic cells, with in vivo consequences. This review provides updated information and describes the tools that A. baumannii possesses to adhere, colonize, and replicate in host cells. Additionally, we emphasize the high genetic and phenotypic heterogeneity detected amongst A. baumannii isolates and its impact on the bacterial intracellular features. We also discuss the need for standardized methods to characterize this pathogen robustly and consequently consider some strains as facultative intracellular bacteria.
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Affiliation(s)
- Alexandra Maure
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Etienne Robino
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Charles Van der Henst
- Microbial Resistance and Drug Discovery, VIB-VUB Center for Structural Biology, VIB, Flanders Institute for Biotechnology, Brussels, Belgium; Structural Biology Brussels, Vrije Universiteit Brussel (VUB), Brussels, Belgium.
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Li Y, Liu L, Xiao C, Sun B, Luo S, Yang D, Zhang X, Huang T, Yu Z, Li X. Outer membrane protein A of Acinetobacter baumannii regulates pulmonary inflammation through the TLR2-NF-κB pathway. Vet Microbiol 2023; 284:109812. [PMID: 37343456 DOI: 10.1016/j.vetmic.2023.109812] [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: 10/01/2022] [Revised: 06/07/2023] [Accepted: 06/10/2023] [Indexed: 06/23/2023]
Abstract
Acinetobacter baumannii (A. baumannii) is characterized by a high prevalence of drug resistance; how to effectively treat it is still a major clinical challenge. Our previous experiments confirmed that ompA, which is one of the most well-characterized virulence factors, may be dependent on the caspase-1 pathway-stimulated expression of NLRP3 inflammasome to enhance inflammation. TLRs (i.e., TLR2, etc.) is the initiating signal for NLRP3 inflammasome activation; how it relates to ompA in its underlying pathogenic mechanism is not clear. In this study, we proofed that ompA promoted NLRP3 inflammasome activation while the TLR2-NF-κB pathway was also activated after A. baumannii infection. Additionally, the expression of NLRP3 inflammasome-associated proteins and genes was inhibited by silencing TLR2 and NLRP3. This indicated that ompA might depend on the TLR2-NF-κB pathway to assemble and activate the NLRP3 inflammasome. OmpA promoted the assembly of the NLRP3 inflammasome through the TLR2-NF-κB pathway and inhibited the degradation of caspase-1 by the proteasome so that a large number of mature IL-1β/IL-18 and other proinflammatory factors were released extracellularly to enhance the body's inflammatory response. Taken together, the results of the joint pre-study confirmed a novel TLR2-NF-κB/NLRP3/caspase-1-modulated mechanism underpinning ompA activity, the NLRP3 inflammasome pathway may be as a potential immunomodulatory target against A. baumannii infections.
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Affiliation(s)
- Yumei Li
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Laibing Liu
- Department of Neurosurgery, Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou 550004, China
| | - Chaolun Xiao
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Baofei Sun
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Shipeng Luo
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Dan Yang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Xiangyan Zhang
- Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital,Guiyang, Guiyang, Guizhou 550006, China
| | - Tao Huang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
| | - Zijiang Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China.
| | - Xiaoying Li
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Nephrology, Guiyang First People's Hospital, Guiyang, Guizhou 550025, China
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Shadan A, Pathak A, Ma Y, Pathania R, Singh RP. Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infection. Front Cell Infect Microbiol 2023; 13:1053968. [PMID: 36968113 PMCID: PMC10038080 DOI: 10.3389/fcimb.2023.1053968] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 02/06/2023] [Indexed: 02/25/2023] Open
Abstract
Deciphering the virulence factors, regulation, and immune response to Acinetobacter baumannii infectionAcinetobacter baumannii is a gram-negative multidrug-resistant nosocomial pathogen and a major cause of hospital acquired infetions. Carbapenem resistant A. baumannii has been categorised as a Priority1 critial pathogen by the World Health Organisation. A. baumannii is responsible for infections in hospital settings, clinical sectors, ventilator-associated pneumonia, and bloodstream infections with a mortality rates up to 35%. With the development of advanced genome sequencing, molecular mechanisms of manipulating bacterial genomes, and animal infection studies, it has become more convenient to identify the factors that play a major role in A. baumannii infection and its persistence. In the present review, we have explored the mechanism of infection, virulence factors, and various other factors associated with the pathogenesis of this organism. Additionally, the role of the innate and adaptive immune response, and the current progress in the development of innovative strategies to combat this multidrug-resistant pathogen is also discussed.
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Affiliation(s)
- Afreen Shadan
- Department of Microbiology, Dr. Shyama Prasad Mukherjee University, Ranchi, Jharkhand, India
| | - Avik Pathak
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
| | - Ying Ma
- College of Resources and Environment, Southwest University, Chongqing, China
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
| | - Ranjana Pathania
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Roorkee, India
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
| | - Rajnish Prakash Singh
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Ranchi, Jharkhand, India
- *Correspondence: Ying Ma, ; Ranjana Pathania, ; Rajnish Prakash Singh,
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Qin J, Zou C, Tao J, Wei T, Yan L, Zhang Y, Wang H. Carbapenem Resistant Pseudomonas aeruginosa Infections in Elderly Patients: Antimicrobial Resistance Profiles, Risk Factors and Impact on Clinical Outcomes. Infect Drug Resist 2022; 15:2301-2314. [PMID: 35517901 PMCID: PMC9064054 DOI: 10.2147/idr.s358778] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 04/13/2022] [Indexed: 12/28/2022] Open
Abstract
Objective The prevalence and clinical impact on mortality of carbapenem-resistant Pseudomonas aeruginosa (CRPA) infection are unclear in elderly patients. Here, we aimed to clarify the prevalence, the clinical manifestations, antimicrobial resistance, risk factors and outcomes of elderly inpatients with CRPA infection. Methods A retrospective study of 600 elderly inpatients infected with P. aeruginosa was conducted at Yueyang Hospital of Integrated Traditional Chinese and Western Medicine from January 1st 2018 to December 31st 2020. All 155 patients with CRPA infection were designated as a case group. Patients with carbapenem-susceptible Pseudomonas aeruginosa (CSPA) were randomly selected from remaining 445 cases in a 1:1 ratio to case group as a control group. Results Of 600 P. aeruginosa isolates, the overall rates of CRPA, MDR PA (multidrug-resistance Pseudomonas aeruginosa) were 25.8% (155), 22.3% (134), respectively. The rankings of the top five resistant rates of CRPA to tested antimicrobial drugs were imipenem (87.7%), meropenem (70.3%), ciprofloxacin (51.0%), levofloxacin (48.4%), cefoperazone (43.2%). Independent risk factors for patients with CRPA infection were cerebrovascular disease (OR = 3.517, P < 0.001), foley catheter (OR = 2.073, P = 0.018), length of hospital stay ≥ 14 days (OR = 1.980, P = 0.013), albumin < 35 g/L (OR = 2.049, P = 0.020), previous antibiotic exposure to carbapenems (OR = 7.022, P = 0.004), previous antibiotic exposure to third- or fourth-generation cephalosporins (OR = 12.649, P = 0.002). Of 155 patients with CRPA infection, the mortality rate was 16.8% (26/155). Independent risk factors for mortality were receiving mechanical ventilation (OR = 3.671, P = 0.007) and neutrophil percentage ≥ 80% (OR = 2.908, P = 0.024). Conclusion The study revealed high rates of CRPA, MDR PA among the hospitalized elderly patient with P. aeruginosa infection. The analysis of antimicrobial susceptibility emphasizes the necessity for antimicrobial stewardship and infection control in hospitals. These findings of risk factors are practical significant to identify patients at high risk for CRPA infection and mortality that may benefit from alternate empiric treatment.
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Affiliation(s)
- Jie Qin
- Department of Clinical Laboratory, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
- Department of Medical Technology, Yueyang Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Chengyun Zou
- Department of Medical Technology, Yueyang Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Jianmin Tao
- Department of Clinical Laboratory, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Tian Wei
- Department of Clinical Laboratory, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Li Yan
- Department of Clinical Laboratory, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Yufei Zhang
- Department of Medical Technology, Yueyang Clinical Medical College, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Haiying Wang
- Department of Clinical Laboratory, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
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Tansho-Nagakawa S, Sato Y, Ubagai T, Kikuchi-Ueda T, Kamoshida GO, Nishida S, Ono Y. Histopathological Analysis of Acinetobacter baumannii Lung Infection in a Mouse Model. Pol J Microbiol 2022; 70:469-477. [PMID: 35003278 PMCID: PMC8702610 DOI: 10.33073/pjm-2021-044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 10/31/2021] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is the main causative pathogen of nosocomial infections that causes severe infections in the lungs. In this study, we analyzed the histopathological characteristics of lung infection with two strains of A. baumannii (ATCC 19606 and the clinical isolate TK1090) and Pseudomonas aeruginosa PAO-1 in C3H/HeN mice to evaluate the virulence of A. baumannii. Survival was evaluated over 14 days. At 1, 2, 5, or 14 days postinfection, mice of C3H/HeN were sacrificed, and histopathological analysis of lung specimens was also performed. Histopathological changes and accumulation of neutrophils and macrophages in the lungs after infection with A. baumannii and P. aeruginosa were analyzed. Following intratracheal inoculation, the lethality of ATCC 19606- and TK1090-infected mice was lower than that of PAO-1-infected mice. However, when mice were inoculated with a sub-lethal dose of A. baumannii, the lung bacterial burden remained in the mice until 14 days post-infection. Additionally, histopathological analysis revealed that macrophages infiltrated the lung foci of ATCC 19606-, TK1090-, and PAO-1-infected mice. Although neutrophils infiltrated the lung foci of ATCC 19606- and TK1090-infected mice, they poorly infiltrated the lung foci of PAO-1-infected mice. Accumulation of these cells in the lung foci of ATCC 19606- and TK1090-infected mice, but not PAO-1-infected mice, was observed for 14 days post-infection. These results suggest that A. baumannii is not completely eliminated despite the infiltration of immune cells in the lungs and that inflammation lasts for prolonged periods in the lungs. Further studies are required to understand the mechanism of A. baumannii infection, and novel drugs and vaccines should be developed to prevent A. baumannii infection.
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Affiliation(s)
- Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - G O Kamoshida
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
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Hatefi Oskuei R, Darvish Alipour Astaneh S, Rasooli I. A conserved region of Acinetobacter trimeric autotransporter adhesion, Ata, provokes suppression of Acinetobacter baumannii virulence. Arch Microbiol 2021; 203:3483-3493. [PMID: 33907866 DOI: 10.1007/s00203-021-02343-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 04/17/2021] [Accepted: 04/21/2021] [Indexed: 01/02/2023]
Abstract
The Acinetobacter trimeric autotransporter adhesin (Ata) is an important virulence factor. The conserved region from the genomic sequence of a 6777bp/2258 amino acid of Acinetobacter baumannii ATCC®19606™ ata was explored. A 263aa of the C-terminal of Ata (rcAta263) was expressed. The effect of rcAta263 on A. baumannii virulence was studied in a murine model. IgG and IgA were elicited and the mice groups challenged with A. baumannii showed significant survival rates from 66 to 100%. The bacterial loads were determined in the spleens, livers, and lungs of both control and test groups. The adhesion rate of A. baumannii to A549 cells in the presence of serum, cytotoxicity, mutagenicity, and biofilm disruption potential of rcAta263 were determined. Intraperitoneally challenged groups showed a significantly reduced bacterial load in the organs of the immunized mice. Intranasal challenge reduced 4 logs of bacterial CFU/g in the test group. The immunized mice sera reduced adherence of A. baumannii to A549 cells to 80%. No cytotoxic or mutagenic effect was detected. Biofilm disruption was significantly increased in the presence of immunized mice sera. Immunization with the conserved region of Ata significantly combats the virulence of A. baumannii which could be considered as a therapeutic strategy to control A. baumannii infections.
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Affiliation(s)
- Ramin Hatefi Oskuei
- Department of Biology, Shahed University, Tehran-Qom Express way, Tehran, 3319118651, Iran
| | - Shakiba Darvish Alipour Astaneh
- Department of Biotechnology, Semnan University, Central Administration of Semnan University, Campus 1, Semnan, 35131-19111, I. R. of Iran
| | - Iraj Rasooli
- Department of Biology, Shahed University, Tehran-Qom Express way, Tehran, 3319118651, Iran.
- Molecular Microbiology Research Center and Department of Biology, Shahed University, Tehran, Iran.
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Acinetobacter baumannii: An Ancient Commensal with Weapons of a Pathogen. Pathogens 2021; 10:pathogens10040387. [PMID: 33804894 PMCID: PMC8063835 DOI: 10.3390/pathogens10040387] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/19/2021] [Accepted: 03/23/2021] [Indexed: 12/22/2022] Open
Abstract
Acinetobacter baumannii is regarded as a life-threatening pathogen associated with community-acquired and nosocomial infections, mainly pneumonia. The rise in the number of A. baumannii antibiotic-resistant strains reduces effective therapies and increases mortality. Bacterial comparative genomic studies have unraveled the innate and acquired virulence factors of A. baumannii. These virulence factors are involved in antibiotic resistance, environmental persistence, host-pathogen interactions, and immune evasion. Studies on host–pathogen interactions revealed that A. baumannii evolved different mechanisms to adhere to in order to invade host respiratory cells as well as evade the host immune system. In this review, we discuss current data on A. baumannii genetic features and virulence factors. An emphasis is given to the players in host–pathogen interaction in the respiratory tract. In addition, we report recent investigations into host defense systems using in vitro and in vivo models, providing new insights into the innate immune response to A. baumannii infections. Increasing our knowledge of A. baumannii pathogenesis may help the development of novel therapeutic strategies based on anti-adhesive, anti-virulence, and anti-cell to cell signaling pathways drugs.
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El Khatib LS, Yacoub MA, Bdour SM, Shehabi AA. Phagoburst Response Level of Neutrophils to Septic and Non-Septic Acinetobacter baumannii Isolates. Open Microbiol J 2021. [DOI: 10.2174/1874285802115010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background:
Acinetobacter baumannii is an opportunistic pathogen causing community-acquired and nosocomial infections. Dissemination of infection to blood causes septicemia associated with serious morbidity and mortality of patients. Neutrophils are essential for the control of A. baumannii infections by different mechanisms, including oxidative burst.
Aims:
This study was conducted as an attempt to determine the effect of septicemic and non-septicemic A. baumannii isolates on the phagoburst response of neutrophils.
Methods:
Neutrophils were isolated from an immunocompetent individual; chronic myeloid leukemia (CML) and lung solid tumor (ST) patients. The phagoburst response of these neutrophils to various strains of A. baumannii isolated from septic and non-septic patients was investigated by flow cytometer.
Results:
The presence of this pathogen lowered the phagoburst response in the different types of neutrophils compared to their response to the opsonized Escherichia coli. The phagoburst response of the neutrophils from the immunocompetent individual was significantly higher than that of neutrophils from the immunodeficient patients when stimulated by the septicemic or nonsepticemic A. baumannii isolates. The isolate type (septicemic or non-septicemic) had no significant effect on the neutrophil phagoburst response of the immunocompetent individual and a significant effect on the phagoburst response of neutrophils from the immunodeficient patients. The phagoburst response of the neutrophils from the immunodeficient patients stimulated by septicemic A. baumannii isolates was significantly lower than that when neutrophils stimulated by the nonsepticemic isolates. Also, there was a significant difference in the phagoburst response of neutrophils from the CML and ST patients when stimulated by the septicemic and non-septicemic isolates. This observation might be due to the combined effect of virulent A. baumannii isolates and the chemotherapy regime the patient was undertaking.
Conclusion:
The results suggest that both the isolate type and the source of neutrophils have a significant effect on the neutrophil phagoburst response. The potential virulence of the septicemic A. baumannii isolates and dissemination to blood may be dependent on the host’s immune status and the neutrophils phagoburst response.
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Li Y, Peng C, Zhao D, Liu L, Guo B, Shi M, Xiao Y, Yu Z, Yu Y, Sun B, Wang W, Lin J, Yang X, Shao S, Zhang X. Outer membrane protein A inhibits the degradation of caspase-1 to regulate NLRP3 inflammasome activation and exacerbate the Acinetobacter baumannii pulmonary inflammation. Microb Pathog 2021; 153:104788. [PMID: 33571624 DOI: 10.1016/j.micpath.2021.104788] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/29/2020] [Accepted: 01/31/2021] [Indexed: 12/16/2022]
Abstract
Acinetobacter baumannii (A. baumannii), one of the major pathogens that causes severe nosocomial infections, is characterised by a high prevalence of drug resistance. It has been reported that A. baumannii triggers the NOD-like receptor 3 (NLRP3) inflammasome, but the role of its virulence-related outer membrane protein A (ompA) remains unclear. Therefore, this study aimed to explore the effects of ompA on the NLRP3 inflammasome and its underlying molecular mechanisms. Results showed that ompA enhanced inflammatory damage, which was reduced as a result of knockout of the ompA gene. Additionally, ompA-stimulated expression of NLRP3 inflammasome was significantly blocked by silencing caspase-1, but activation of NLRP3 inflammasome was not altered after silencing ASC; this indicated that ompA was dependent on the caspase-1 pathway to activate the inflammatory response. Simultaneously, the wild-type (WT) strains triggered NLRP3 inflammasome after inhibition of caspase-1 degradation by proteasome inhibitor MG-132, aggravating tissue damage. These findings indicated that ompA may be dependent on the caspase-1 pathway to enhance inflammation and exacerbate tissue damage. Taken together, these results confirmed a novel capsase-1-modulated mechanism underpinning ompA activity, which further reveals the NLRP3 inflammasome pathway as a potential immunomodulatory target against A. baumannii infections.
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Affiliation(s)
- Yumei Li
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Chunhong Peng
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Dan Zhao
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Laibing Liu
- Department of Neurosurgery, Affiliated Baiyun Hospital, Guizhou Medical University, Guiyang, Guizhou, 550004, China
| | - Bing Guo
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Mingjun Shi
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Ying Xiao
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Zijiang Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Yan Yu
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Baofei Sun
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China; Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Wenjuan Wang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang, Guizhou, 550025, China
| | - Jieru Lin
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Xiaoyan Yang
- Department of Pediatrics, Affiliated Hospital of Guizhou Medical University, Guiyang, Guizhou, 550004, China
| | - Songjun Shao
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China
| | - Xiangyan Zhang
- Department of Anatomy, School of Basic Medical Sciences, Guizhou Medical University/ Department of Respiratory and Critical Medicine, Guizhou Provincial People's Hospital, Guiyang, Guizhou, 550025, China.
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Sato Y, Tansho-Nagakawa S, Ubagai T, Ono Y. Analysis of Immune Responses in Acinetobacter baumannii-Infected Klotho Knockout Mice: A Mouse Model of Acinetobacter baumannii Infection in Aged Hosts. Front Immunol 2020; 11:601614. [PMID: 33329595 PMCID: PMC7719750 DOI: 10.3389/fimmu.2020.601614] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/27/2020] [Indexed: 12/24/2022] Open
Abstract
Acinetobacter baumannii is an important opportunistic pathogen that primarily afflicts elderly people. To clarify the pathogenicity of A. baumannii in the elderly, we investigated immune responses to A. baumannii ATCC 19606 infection in klotho knockout (KO) mice, the mouse model of aging. Following intravenous inoculation, the mice seldom displayed severe symptoms. However, the survival rate was 56% at 7 days post-infection. Bacteria were detected in the lungs of klotho KO mice but not klotho wildtype (WT) mice at 7 days post-infection. Neutrophils, eosinophils, interstitial macrophages, and monocyte/dendritic cell subset in the lungs of klotho KO mice were transiently induced after infection with A. baumannii. The number of alveolar macrophages in klotho KO mice was lower than that in klotho WT mice, except for 1 day post-infection. CD11b expression on neutrophils and alveolar macrophages in the lungs of klotho KO mice was seldom upregulated by the infection. These results suggested that immune functions eliminating bacteria in the lungs of klotho KO mice were insufficient. CD11blow conventional DC cells hardly increased in klotho KO mice infected with A. baumannii. Additionally, the production of interleukin (IL)-10 in the sera of klotho KO mice was significantly higher than that in klotho WT mice, whereas that production of interferon-gamma was not detected in the sera of klotho KO mice. These results suggested that acquired immune responses were hardly induced in klotho KO mice. IL-1β, CXCL1, CXCL2, and CCL2 expression was significantly higher in the lungs of klotho KO mice infected with A. baumannii than in those of klotho WT mice at 1 day post-infection. These results suggested that pulmonary inflammation was elicited in klotho KO mice during early infection. The expression levels of proinflammatory cytokines significantly correlated with TLR9 expression in the lungs of klotho KO mice. The collective results demonstrate an A. baumannii infection state in aged hosts and suggest that pulmonary inflammation and bacterial burden should be noted in aged hosts even in the absence of severe symptoms of A. baumannii infection.
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Affiliation(s)
- Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, Tokyo, Japan
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11
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Shi J, Sun T, Cui Y, Wang C, Wang F, Zhou Y, Miao H, Shan Y, Zhang Y. Multidrug resistant and extensively drug resistant Acinetobacter baumannii hospital infection associated with high mortality: a retrospective study in the pediatric intensive care unit. BMC Infect Dis 2020; 20:597. [PMID: 32787942 PMCID: PMC7422664 DOI: 10.1186/s12879-020-05321-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 08/03/2020] [Indexed: 02/06/2023] Open
Abstract
Background Multidrug resistant (MDR) and extensively drug resistant (XDR) Acinetobacter baumannii presents challenges for clinical treatment and causes high mortality in children. We aimed to assess the risk factors and overall mortality for MDR/XDR Acinetobacter baumannii infected pediatric patients. Methods This retrospective study included 102 pediatric patients who developed MDR/XDR Acinetobacter baumannii infection in the pediatric intensive care unit (PICU) of Shanghai Children’s Hospital in China from December 2014 to May 2018. Acinetobacter baumannii clinical isolates were recovered from different specimens including blood, sputum, bronchoalveolar lavage fluid, cerebrospinal fluid, ascites, hydrothorax, and urine. Antibiotic susceptibility test was determined according to the Clinical and Laboratory Standards Institute interpretive criteria. Clinical and biological data were obtained from the patients’ medical records. Results 102 patients with Acinetobacter baumannii infection were enrolled. The median age was 36 (9.6, 98.8) months, and there were 63 male in the case group. The overall mortality rate was 29.4%, while the Acinetobacter baumannii-associated mortality rate was 16.7% (17/102, 12 bloodstream infections, 4 meningitis and 1 intra-abdominal infection). Bloodstream infections occurred in 28 patients (27.5%), and 10 patients (9.8%) among them had central line-associated bloodstream infections (6 central venous catheters, 2 PICCs, 1 venous infusion port and 1 arterial catheter). Cerebrospinal fluid (CSF) cultures were positive in 4(3.9%) patients. 14(13.7%) patients got positive cultures in ascites and hydrothorax. Lower respiratory isolates (56/102) accounted for 54.9% of all patients. Non-survival patients appeared to have a lower NK cell activity (6.2% ± 3.61% vs. 9.15% ± 6.21%, P = 0.029), higher CD4+ T cell ratio (39.67% ± 12.18% vs. 32.66% ± 11.44%, P = 0.039),and a higher serum level of interlukin-8 (IL-8, 15.25 (1.62, 47.22)pg/mL vs. 0.1 (0.1, 22.99)pg/mL, P = 0.01) when Acinetobacter baumannii infection developed. Multivariate logistic analysis indicated that high serum level of Cr (RR, 0.934, 95%CI, 0.890–0.981; P = 0.007) and high BUN/ALB level (RR, 107.893, 95%CI, 1.425–870.574; p = 0.005) were associated with high risk of mortality in MDR/XDR Acinetobacter baumannii infected patients. Conclusion MDR/XDR Acinetobacter baumannii infection is a serious concern in pediatric patients with high mortality. Bloodstream and central nervous system infection accounted for high risk of death. Acute kidney injury is associated with high risk of mortality.
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Affiliation(s)
- Jingyi Shi
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Ting Sun
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Yun Cui
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Chunxia Wang
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China.,Institute of Pediatric Critical Care, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Fei Wang
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Yiping Zhou
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Huijie Miao
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Yijun Shan
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China
| | - Yucai Zhang
- Department of Critical Care Medicine, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, 20062, China. .,Institute of Pediatric Critical Care, Shanghai Jiao Tong University, Shanghai, 20062, China. .,Department of Critical Care Medicine, Shanghai, Children's Hospital, Shanghai Jiao Tong University, No.355 Luding Road, Putuo District, Shanghai, 200062, China.
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12
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Monem S, Furmanek-Blaszk B, Łupkowska A, Kuczyńska-Wiśnik D, Stojowska-Swędrzyńska K, Laskowska E. Mechanisms Protecting Acinetobacter baumannii against Multiple Stresses Triggered by the Host Immune Response, Antibiotics and Outside-Host Environment. Int J Mol Sci 2020; 21:E5498. [PMID: 32752093 PMCID: PMC7432025 DOI: 10.3390/ijms21155498] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii is considered one of the most persistent pathogens responsible for nosocomial infections. Due to the emergence of multidrug resistant strains, as well as high morbidity and mortality caused by this pathogen, A. baumannii was placed on the World Health Organization (WHO) drug-resistant bacteria and antimicrobial resistance research priority list. This review summarizes current studies on mechanisms that protect A. baumannii against multiple stresses caused by the host immune response, outside host environment, and antibiotic treatment. We particularly focus on the ability of A. baumannii to survive long-term desiccation on abiotic surfaces and the population heterogeneity in A. baumannii biofilms. Insight into these protective mechanisms may provide clues for the development of new strategies to fight multidrug resistant strains of A. baumannii.
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Affiliation(s)
- Soroosh Monem
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Beata Furmanek-Blaszk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Adrianna Łupkowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Dorota Kuczyńska-Wiśnik
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Karolina Stojowska-Swędrzyńska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
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13
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Depletion of Alveolar Macrophages Increases Pulmonary Neutrophil Infiltration, Tissue Damage, and Sepsis in a Murine Model of Acinetobacter baumannii Pneumonia. Infect Immun 2020; 88:IAI.00128-20. [PMID: 32366576 DOI: 10.1128/iai.00128-20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/30/2020] [Indexed: 12/14/2022] Open
Abstract
Acinetobacter baumannii has emerged as an important etiological agent of hospital-related infections, especially nosocomial pneumonia. The virulence factors of this bacterium and their interactions with the cells and molecules of the immune system just recently began to be extensively studied. Here, we investigated the impact of alveolar macrophages on A. baumannii pneumonia using a mouse model of infection and a flexible tissue culture system. We hypothesized that depletion of macrophages would enhance sepsis and severity of A. baumannii disease. We showed that macrophages are important for modulating the antibacterial function of neutrophils and play an important role in eradicating A. baumannii infection in vivo Our findings suggest that in the absence of macrophages in the lungs, A. baumannii replicates significantly, and host proinflammatory cytokines are considerably reduced. Neutrophils are abundantly recruited to pulmonary tissue, releasing high amounts of reactive oxygen species and causing extensive tissue damage. The ability of A. baumannii to form biofilms and resist oxidative stress in the respiratory tract facilitates systemic dissemination and ultimately death of infected C57BL/6 mice. These results provide novel information regarding A. baumannii pathogenesis and may be important for the development of therapies aimed at reducing morbidity and mortality associated with this emerging bacterial pathogen.
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14
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Kamoshida G, Akaji T, Takemoto N, Suzuki Y, Sato Y, Kai D, Hibino T, Yamaguchi D, Kikuchi-Ueda T, Nishida S, Unno Y, Tansho-Nagakawa S, Ubagai T, Miyoshi-Akiyama T, Oda M, Ono Y. Lipopolysaccharide-Deficient Acinetobacter baumannii Due to Colistin Resistance Is Killed by Neutrophil-Produced Lysozyme. Front Microbiol 2020; 11:573. [PMID: 32373082 PMCID: PMC7183746 DOI: 10.3389/fmicb.2020.00573] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/16/2020] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii causes nosocomial infections due to its multidrug resistance and high environmental adaptability. Colistin is a polypeptide antibacterial agent that targets lipopolysaccharide (LPS) and is currently used to control serious multidrug-resistant Gram-negative bacterial infections, including those caused by A. baumannii. However, A. baumannii may acquire colistin resistance by losing their LPS. In mouse models, LPS-deficient A. baumannii have attenuated virulence. Nevertheless, the mechanism through which the pathogen is cleared by host immune cells is unknown. Here, we established colistin-resistant A. baumannii strains and analyzed possible mechanisms through which they are cleared by neutrophils. Colistin-resistant, LPS-deficient strains harbor mutations or insertion sequence (IS) in lpx genes, and introduction of intact lpx genes restored LPS deficiency. Analysis of interactions between these strains and neutrophils revealed that compared with wild type, LPS-deficient A. baumannii only weakly stimulated neutrophils, with consequent reduced levels of reactive oxygen species (ROS) and inflammatory cytokine production. Nonetheless, neutrophils preferentially killed LPS-deficient A. baumannii compared to wild-type strains. Moreover, LPS-deficient A. baumannii strains presented with increased sensitivities to antibacterial lysozyme and lactoferrin. We revealed that neutrophil-secreted lysozyme was the antimicrobial factor during clearance of LPS-deficient A. baumannii strains. These findings may inform the development of targeted therapeutics aimed to treat multidrug-resistant infections in immunocompromised patients who are unable to mount an appropriate cell-mediated immune response.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan.,Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Takuya Akaji
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Norihiko Takemoto
- Pathogenic Microbe Laboratory, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yusuke Suzuki
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yoshinori Sato
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Daichi Kai
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Taishi Hibino
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daiki Yamaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yuka Unno
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tohru Miyoshi-Akiyama
- Pathogenic Microbe Laboratory, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Masataka Oda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
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15
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Multidrug-resistant Acinetobacter baumannii resists reactive oxygen species and survives in macrophages. Sci Rep 2019; 9:17462. [PMID: 31767923 PMCID: PMC6877552 DOI: 10.1038/s41598-019-53846-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 11/06/2019] [Indexed: 01/27/2023] Open
Abstract
We investigated the intracellular survival of multidrug-resistant Acinetobacter baumannii (MDRAB) clinical isolates in macrophages, after phagocytosis, to determine their virulence characteristics. After ATCC 19606 and 5 clinical isolates of MDRAB were phagocytosed by mouse and human macrophages, the bacterial count of MDRAB strains, R4 and R5, increased in the mouse macrophages, 24 hours after phagocytosis. Bacterial count of the strains, R1 and R2, was almost equal 4 and 24 hours after phagocytosis. Intracellular reactive oxygen species was detected in the macrophages after phagocytosis of these bacteria. Further, the strains R1, R2, R4, and R5 showed higher catalase activity than ATCC 19606. Additionally, strains R1, R4, and R5 grew more efficiently than ATCC 19606 in the presence of H2O2, whereas growth of strains R2 and R3 was marginally more than that of ATCC 19606 in the presence of H2O2. The MDRAB clinical isolates altered the expression of TNF-α, IL-1β, IL-6, and MIP-2 mRNA induced in J774A.1 cells, 24 hours after phagocytosis. These results provide insights into the renewed virulence characteristics of MDRAB clinical isolates. Finally, tigecycline killed MDRAB phagocytosed by the macrophages more effectively than colistin, although colistin and tigecycline are both considered effective antibiotics for the treatment of MDRAB.
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16
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Morris FC, Dexter C, Kostoulias X, Uddin MI, Peleg AY. The Mechanisms of Disease Caused by Acinetobacter baumannii. Front Microbiol 2019; 10:1601. [PMID: 31379771 PMCID: PMC6650576 DOI: 10.3389/fmicb.2019.01601] [Citation(s) in RCA: 142] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 06/26/2019] [Indexed: 01/29/2023] Open
Abstract
Acinetobacter baumannii is a Gram negative opportunistic pathogen that has demonstrated a significant insurgence in the prevalence of infections over recent decades. With only a limited number of “traditional” virulence factors, the mechanisms underlying the success of this pathogen remain of great interest. Major advances have been made in the tools, reagents, and models to study A. baumannii pathogenesis, and this has resulted in a substantial increase in knowledge. This article provides a comprehensive review of the bacterial virulence factors, the host immune responses, and animal models applicable for the study of this important human pathogen. Collating the most recent evidence characterizing bacterial virulence factors, their cellular targets and genetic regulation, we have encompassed numerous aspects important to the success of this pathogen, including membrane proteins and cell surface adaptations promoting immune evasion, mechanisms for nutrient acquisition and community interactions. The role of innate and adaptive immune responses is reviewed and areas of paucity in our understanding are highlighted. Finally, with the vast expansion of available animal models over recent years, we have evaluated those suitable for use in the study of Acinetobacter disease, discussing their advantages and limitations.
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Affiliation(s)
- Faye C Morris
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Carina Dexter
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Xenia Kostoulias
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Muhammad Ikhtear Uddin
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
| | - Anton Y Peleg
- Infection and Immunity Program, Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia.,Department of Infectious Diseases, The Alfred Hospital and Central Clinical School, Monash University, Melbourne, VIC, Australia
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17
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Pires S, Parker D. Innate Immune Responses to Acinetobacter baumannii in the Airway. J Interferon Cytokine Res 2019; 39:441-449. [PMID: 31013462 DOI: 10.1089/jir.2019.0008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Acinetobacter baumannii is an emerging opportunistic pathogen that has risen to become a serious global threat, prevalent in health care settings and the community, which results in high morbidity and mortality rates. Its alarming expansion of antibiotic resistance is one of the most problematic traits of A. baumannii and as so, this bacterium has been classified as a serious threat and high priority target by the CDC. The most common types of infections induced by this pathogen include pneumonia (both hospital and community acquired), bacteremia, skin and soft tissue, urinary tract infections, endocarditis, and meningitis. Nosocomial pneumonia is the most prevalent of these. This review summarizes the current state of the signaling and innate immune components activated in response to A. baumannii infection in the airway.
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Affiliation(s)
- Sílvia Pires
- Department of Pathology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Dane Parker
- Department of Pathology and Laboratory Medicine, Center for Immunity and Inflammation, Rutgers New Jersey Medical School, Newark, New Jersey
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18
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Kamoshida G, Kikuchi-Ueda T, Nishida S, Tansho-Nagakawa S, Ubagai T, Ono Y. Pathogenic Bacterium Acinetobacter baumannii Inhibits the Formation of Neutrophil Extracellular Traps by Suppressing Neutrophil Adhesion. Front Immunol 2018; 9:178. [PMID: 29467765 PMCID: PMC5808340 DOI: 10.3389/fimmu.2018.00178] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/19/2018] [Indexed: 12/12/2022] Open
Abstract
Hospital-acquired infections caused by Acinetobacter baumannii have become problematic because of high rates of drug resistance. A. baumannii is usually harmless, but it may cause infectious diseases in an immunocompromised host. Although neutrophils are the key players of the initial immune response against bacterial infection, their interactions with A. baumannii remain largely unknown. A new biological defense mechanism, termed neutrophil extracellular traps (NETs), has been attracting attention. NETs play a critical role in bacterial killing by bacterial trapping and inactivation. Many pathogenic bacteria have been reported to induce NET formation, while an inhibitory effect on NET formation is rarely reported. In the present study, to assess the inhibition of NET formation by A. baumannii, bacteria and human neutrophils were cocultured in the presence of phorbol 12-myristate 13-acetate (PMA), and NET formation was evaluated. NETs were rarely observed during the coculture despite neutrophil PMA stimulation. Furthermore, A. baumannii prolonged the lifespan of neutrophils by inhibiting NET formation. The inhibition of NET formation by other bacteria was also investigated. The inhibitory effect was only apparent with live A. baumannii cells. Finally, to elucidate the mechanism of this inhibition, neutrophil adhesion was examined. A. baumannii suppressed the adhesion ability of neutrophils, thereby inhibiting PMA-induced NET formation. This suppression of cell adhesion was partly due to suppression of the surface expression of CD11a in neutrophils. The current study constitutes the first report on the inhibition of NET formation by a pathogenic bacterium, A. baumannii, and prolonging the neutrophil lifespan. This novel pathogenicity to inhibit NET formation, thereby escaping host immune responses might contribute to a development of new treatment strategies for A. baumannii infections.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
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19
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Lázaro-Díez M, Chapartegui-González I, Redondo-Salvo S, Leigh C, Merino D, Segundo DS, Fernández A, Navas J, Icardo JM, Acosta F, Ocampo-Sosa A, Martínez-Martínez L, Ramos-Vivas J. Human neutrophils phagocytose and kill Acinetobacter baumannii and A. pittii. Sci Rep 2017; 7:4571. [PMID: 28676640 PMCID: PMC5496873 DOI: 10.1038/s41598-017-04870-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 05/22/2017] [Indexed: 12/23/2022] Open
Abstract
Acinetobacter baumannii is a common cause of health care associated infections worldwide. A. pittii is an opportunistic pathogen also frequently isolated from Acinetobacter infections other than those from A. baumannii. Knowledge of Acinetobacter virulence factors and their role in pathogenesis is scarce. Also, there are no detailed published reports on the interactions between A. pittii and human phagocytic cells. Using confocal laser and scanning electron microscopy, immunofluorescence, and live-cell imaging, our study shows that immediately after bacteria-cell contact, neutrophils rapidly and continuously engulf and kill bacteria during at least 4 hours of infection in vitro. After 3 h of infection, neutrophils start to release neutrophil extracellular traps (NETs) against Acinetobacter. DNA in NETs colocalizes well with human histone H3 and with the specific neutrophil elastase. We have observed that human neutrophils use large filopodia as cellular tentacles to sense local environment but also to detect and retain bacteria during phagocytosis. Furthermore, co-cultivation of neutrophils with human differentiated macrophages before infections shows that human neutrophils, but not macrophages, are key immune cells to control Acinetobacter. Although macrophages were largely activated by both bacterial species, they lack the phagocytic activity demonstrated by neutrophils.
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Affiliation(s)
- María Lázaro-Díez
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, 39008, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, 28029, Spain
| | - Itziar Chapartegui-González
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, 39008, Spain
| | | | - Chike Leigh
- New York University School of Medicine, New York, 10003, USA
| | - David Merino
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
- Servicio de Inmunología, Hospital Universitario Marqués de Valdecilla, Santander, 39008, Spain
| | - David San Segundo
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
- Servicio de Inmunología, Hospital Universitario Marqués de Valdecilla, Santander, 39008, Spain
| | - Adrián Fernández
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
| | - Jesús Navas
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
- Departamento de Biología Molecular, Universidad de Cantabria, Santander, 39011, Spain
| | - José Manuel Icardo
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria, Santander, 39011, Spain
| | - Félix Acosta
- Grupo de Investigación en Acuicultura, Universidad de Las Palmas de Gran Canaria, Gran Canaria, 35214, Spain
| | - Alain Ocampo-Sosa
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, 39008, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, 28029, Spain
| | - Luis Martínez-Martínez
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, 28029, Spain
- Unidad de Gestión Clínica de Microbiología, Hospital Universitario Reina Sofía, Córdoba, 14004, Spain
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, 14004, Spain
| | - José Ramos-Vivas
- Instituto de Investigación Valdecilla IDIVAL, Santander, 39011, Spain.
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, 39008, Spain.
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, 28029, Spain.
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20
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Kamoshida G, Kikuchi-Ueda T, Nishida S, Tansho-Nagakawa S, Kikuchi H, Ubagai T, Ono Y. Spontaneous formation of neutrophil extracellular traps in serum-free culture conditions. FEBS Open Bio 2017; 7:877-886. [PMID: 28593142 PMCID: PMC5458474 DOI: 10.1002/2211-5463.12222] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 03/02/2017] [Accepted: 03/20/2017] [Indexed: 01/05/2023] Open
Abstract
Neutrophils play a critical role in the innate immune response. Recently, a new neutrophilic biological defense mechanism, termed neutrophil extracellular traps (NETs), has been attracting attention. Neutrophils have been observed to release both lysosomal enzymes and their nuclear contents, including unfolded chromatin, which together trap and inactivate bacteria. The environment in tissues where neutrophils act is thought to be different from that of the blood serum. In this study, we assessed the effect of serum on NET formation. We found that neutrophils spontaneously form NETs in serum‐free cultivation conditions at early times. These NETs functioned properly to trap bacteria. Furthermore, we demonstrated that reactive oxygen species play a critical role in the spontaneous formation of NETs. These results suggest that the serum condition must be considered in studies on neutrophils, including the formation and mechanism of action of NETs.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Immunology Teikyo University School of Medicine Tokyo Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology Teikyo University School of Medicine Tokyo Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology Teikyo University School of Medicine Tokyo Japan
| | | | - Hirotoshi Kikuchi
- Department of Microbiology and Immunology Teikyo University School of Medicine Tokyo Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology Teikyo University School of Medicine Tokyo Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology Teikyo University School of Medicine Tokyo Japan
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García-Patiño MG, García-Contreras R, Licona-Limón P. The Immune Response against Acinetobacter baumannii, an Emerging Pathogen in Nosocomial Infections. Front Immunol 2017; 8:441. [PMID: 28446911 PMCID: PMC5388700 DOI: 10.3389/fimmu.2017.00441] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 03/29/2017] [Indexed: 12/18/2022] Open
Abstract
Acinetobacter baumannii is the etiologic agent of a wide range of nosocomial infections, including pneumonia, bacteremia, and skin infections. Over the last 45 years, an alarming increase in the antibiotic resistance of this opportunistic microorganism has been reported, a situation that hinders effective treatments. In order to develop effective therapies against A. baumannii it is crucial to understand the basis of host–bacterium interactions, especially those concerning the immune response of the host. Different innate immune cells such as monocytes, macrophages, dendritic cells, and natural killer cells have been identified as important effectors in the defense against A. baumannii; among them, neutrophils represent a key immune cell indispensable for the control of the infection. Several immune strategies to combat A. baumannii have been identified such as recognition of the bacteria by immune cells through pattern recognition receptors, specifically toll-like receptors, which trigger bactericidal mechanisms including oxidative burst and cytokine and chemokine production to amplify the immune response against the pathogen. However, a complete picture of the protective immune strategies activated by this bacteria and its potential therapeutic use remains to be determined and explored.
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Affiliation(s)
- María Guadalupe García-Patiño
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Rodolfo García-Contreras
- Facultad de Medicina, Departamento de Microbiología y Parasitología, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Paula Licona-Limón
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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Sato Y, Unno Y, Kawakami S, Ubagai T, Ono Y. Virulence characteristics of Acinetobacter baumannii clinical isolates vary with the expression levels of omps. J Med Microbiol 2017; 66:203-212. [PMID: 27902395 DOI: 10.1099/jmm.0.000394] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE We investigated the expression levels of virulence factors (ompA, omp33-36 and carO) in five clinical isolates and in a standard ATCC 19606 strain of Acinetobacter baumannii to determine their effect on the virulence characteristics of the isolates. METHODOLOGY The mRNA levels of omps and proinflammatory cytokines were analyzed by quantitative real-time PCR. For adherence assay, after human lung epithelial cells (A549) were co-cultured with A. baumannii at 37 °C for 2 h, the cell-adherent bacteria was counted. Pearson correlation analysis was used to compare the omps mRNA levels, the proinflammatory cytokines and the number of adherent bacteria. RESULTS The mRNA levels of ompA in the clinical isolates were higher and similar compared with those in ATCC 19606, whereas the mRNA levels of omp33-36 in the clinical isolates were lower and similar compared with those in ATCC 19606. The mRNA levels of carO in the clinical isolates were significantly higher than those in ATCC 19606. The number of cell-adherent clinical isolates was higher than that of cell-adherent ATCC 19606. Furthermore, the number of cell-adherent clinical isolates was positively and significantly correlated with ompA mRNA level. The mRNA levels of TNF-α, IL-6 and IL-8 in A549 cells co-cultured with the clinical isolates were lower than those in A549 cells co-cultured with ATCC 19606. Moreover, the mRNA levels of TNF-α, IL-6 and IL-8 were negatively and significantly correlated with those of carO in the isolates. CONCLUSION These results provide insights into the renewed virulence characteristics of A. baumannii clinical isolates that depend on cell adherence capacity and the expression level of omp mRNAs.
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Affiliation(s)
- Yoshinori Sato
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yuka Unno
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Sayoko Kawakami
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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