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Hu YY, Chen S, Zhang YD, Lu QW, Wang F, Ren A, Liu CX. Value of T6SS Core Gene hcp in Acinetobacter baumannii Respiratory Tract Infection. Indian J Microbiol 2023; 63:291-298. [PMID: 37781009 PMCID: PMC10533764 DOI: 10.1007/s12088-023-01083-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 06/27/2023] [Indexed: 10/03/2023] Open
Abstract
Hospital-acquired pneumonia caused by Acinetobacter baumannii is a major healthcare burden. Type VI Secretion System (T6SS) contributes to both virulence and drug resistance in this bacteria. This study aims to investigate the diagnostic value of hemolysin co-regulated protein (Hcp) gene in A. baumannii pneumonia and further explore the effect of hcp on clinical, pathogenicity and drug resistance. 53 clinical A. baumannii strains from patients' respiratory tract at a teaching hospital were included in this study. Real-time quantitative polymerase chain reaction (qRT-PCR) was carried out to examine the expression of hcp. Recombinant Hcp expression plasmids (pET-28a(+)-hcp) were constructed and his-tagged Hcp were purified to stimulate Tohoku Hospital Pediatrics-1 (THP-1) macrophages. Nuclear Factor Kappa B p65 (NF-κBp65) and Interleukin 8 (IL-8) were detected by qRT-PCR. Antimicrobial susceptibility testing (AST) were examined by an automated instrument system. Hcp gene had 92.6% sensitivity and 75% specificity for distinguishing invasive or colonizing A. baumannii from the respiratory tract. His-tagged Hcp induced NF-κBp65 and IL-8 at gene level in THP-1 macrophages. Additional, high hcp expression isolates showed higher rate of antimicrobial agent exposure (< 30 days) of carbapenems, antibiotic combination therapy and multiple or extensive drug-resistant (MDR/XDR) and exhibited higher resistance rate to clinical commonly-used antimicrobial agents. Hcp gene could serve as a novel diagnostic biomarker to distinguish A. baumannii respiratory tract infection from colonization and participate in eliciting inflammatory responses in vitro. T6SS/hcp may play a role in the development of carbapenem-resistant A. baumannii (CRAB), multiple or extensive drug-resistant A. baumannii (MDRAB/XDRAB). Supplementary Information The online version contains supplementary material available at 10.1007/s12088-023-01083-8.
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Affiliation(s)
- Yin-yin Hu
- Department of Clinical Laboratory, Nanyang Central Hospital, Nanyang, 473000 Henan Province China
| | - Shuo Chen
- Department of Infection Control, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000 Zhejiang Province China
| | - Ya-dong Zhang
- Department of Breast Surgery, Nan yang Second General Hospital, Nanyang, 473000 Henan Province China
| | - Qing-wen Lu
- Department of Clinical Laboratory, Nanyang Central Hospital, Nanyang, 473000 Henan Province China
| | - Fei Wang
- Department of Clinical Laboratory, Nanyang Central Hospital, Nanyang, 473000 Henan Province China
| | - Aijuan Ren
- Department of Clinical Laboratory, The Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, 325000 Zhejiang Province China
| | - Cai-xia Liu
- Department of Clinical Laboratory, The Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, 325000 Zhejiang Province China
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Chi Y, Jiao H, Ran J, Xiong C, Wei J, Ozdemir E, Wu R. Construction and efficacy of Aeromonas veronii mutant Δhcp as a live attenuated vaccine for the largemouth bass (Micropterus salmoides). Fish Shellfish Immunol 2023; 136:108694. [PMID: 36944414 DOI: 10.1016/j.fsi.2023.108694] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 06/18/2023]
Abstract
Aeromonas veronii is a human and animal co-pathogenic bacterium that could have a significant negative impact on both human health and aquaculture. In this study, a mutant strain of A. veronii with deletion of the hemolysin co-regulated protein (hcp) gene was constructed (Δhcp-AV). Compared with the wild strain, Δhcp-AV showed significantly reduced growth capacity and biofilm formation ability. Motility tests showed that the hcp gene had no significant effect on the swimming and swarming ability. In addition, the pathogenicity was also reduced. To evaluate the efficacy of Δhcp-AV as a live attenuated vaccine for prevention of Aeromonas veronii infection, we compared the immune response of largemouth bass (Micropterus salmoides) after immunization with 500 μL of 1.47 × 105 CFU/mL of Δhcp-AV and 4 × 108 CFU/mL of inactivated A. veronii. Obvious increases of serum immune related enzyme activity were observed in immunization groups. Expression levels of immune-related genes in Δhcp-AV group were up-regulated, and higher than those in inactivated A. veronii group. After challenging with live A. veronii, the relative percent survival (RPS) was 100% in Δhcp- AV group, whereas the RPS was 76.67% in inactivated A. veronii group. Our data suggest that the live attenuated vaccine Δhcp- AV could elicit a stronger immune response and provide a higher RPS than inactivated A. veronii. These data suggest that hcp gene is an important virulence factor of A. veronii, and the live attenuated vaccine Δhcp-AV is safe and effective for prevention A. veronii infection in M. salmoides farming.
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Affiliation(s)
- Yuyu Chi
- College of Fisheries, Southwest University, Chongqing, 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development, Minister of Education, Southwest University, Chongqing, 400715, China.
| | - Hanyang Jiao
- College of Fisheries, Southwest University, Chongqing, 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development, Minister of Education, Southwest University, Chongqing, 400715, China.
| | - Jiayan Ran
- College of Fisheries, Southwest University, Chongqing, 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development, Minister of Education, Southwest University, Chongqing, 400715, China.
| | - Chuanyu Xiong
- College of Fisheries, Southwest University, Chongqing, 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development, Minister of Education, Southwest University, Chongqing, 400715, China.
| | - Jinming Wei
- College of Fisheries, Southwest University, Chongqing, 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development, Minister of Education, Southwest University, Chongqing, 400715, China.
| | - Eda Ozdemir
- Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS, 39762, USA.
| | - Ronghua Wu
- College of Fisheries, Southwest University, Chongqing, 400715, China; Key Laboratory of Freshwater Fish Reproduction and Development, Minister of Education, Southwest University, Chongqing, 400715, China.
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