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Liu X, de Bakker V, Heggenhougen MV, Mårli MT, Frøynes AH, Salehian Z, Porcellato D, Morales Angeles D, Veening JW, Kjos M. Genome-wide CRISPRi screens for high-throughput fitness quantification and identification of determinants for dalbavancin susceptibility in Staphylococcus aureus. mSystems 2024:e0128923. [PMID: 38837392 DOI: 10.1128/msystems.01289-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 05/01/2024] [Indexed: 06/07/2024] Open
Abstract
Antibiotic resistance and tolerance remain a major problem for the treatment of staphylococcal infections. Identifying genes that influence antibiotic susceptibility could open the door to novel antimicrobial strategies, including targets for new synergistic drug combinations. Here, we developed a genome-wide CRISPR interference library for Staphylococcus aureus, demonstrated its use by quantifying gene fitness in different strains through CRISPRi-seq, and used it to identify genes that modulate susceptibility to the lipoglycopeptide dalbavancin. By exposing the library to sublethal concentrations of dalbavancin using both CRISPRi-seq and direct selection methods, we not only found genes previously reported to be involved in antibiotic susceptibility but also identified genes thus far unknown to affect antibiotic tolerance. Importantly, some of these genes could not have been detected by more conventional transposon-based knockout approaches because they are essential for growth, stressing the complementary value of CRISPRi-based methods. Notably, knockdown of a gene encoding the uncharacterized protein KapB specifically sensitizes the cells to dalbavancin, but not to other antibiotics of the same class, whereas knockdown of the Shikimate pathway showed the opposite effect. The results presented here demonstrate the promise of CRISPRi-seq screens to identify genes and pathways involved in antibiotic susceptibility and pave the way to explore alternative antimicrobial treatments through these insights.IMPORTANCEAntibiotic resistance is a challenge for treating staphylococcal infections. Identifying genes that affect how antibiotics work could help create new treatments. In our study, we made a CRISPR interference library for Staphylococcus aureus and used this to find which genes are critical for growth and also mapped genes that are important for antibiotic sensitivity, focusing on the lipoglycopeptide antibiotic dalbavancin. With this method, we identified genes that altered the sensitivity to dalbavancin upon knockdown, including genes involved in different cellular functions. CRISPRi-seq offers a means to uncover untapped antibiotic targets, including those that conventional screens would disregard due to their essentiality. This paves the way for the discovery of new ways to fight infections.
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Affiliation(s)
- Xue Liu
- Department of Pathogen, Biology, International Cancer Center, Shenzhen University Medical School, Shenzhen, Guangdong, China
- Department of Fundamental Microbiology, University of Lausanne, , Switzerland
| | - Vincent de Bakker
- Department of Fundamental Microbiology, University of Lausanne, , Switzerland
| | | | - Marita Torrissen Mårli
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Anette Heidal Frøynes
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Zhian Salehian
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Davide Porcellato
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Danae Morales Angeles
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
| | - Jan-Willem Veening
- Department of Fundamental Microbiology, University of Lausanne, , Switzerland
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Norway
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Haq IU, Kamal M, Swelum AA, Khan S, Ríos-Escalante PRDL, Usman T. Alarming multidrug resistance in Staphylococcus aureus isolated from raw milk of cows with subclinical mastitis: Antibiotic resistance patterns and occurrence of selected resistance genes. PLoS One 2024; 19:e0301200. [PMID: 38753608 PMCID: PMC11098306 DOI: 10.1371/journal.pone.0301200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 03/12/2024] [Indexed: 05/18/2024] Open
Abstract
Bovine mastitis is a widespread and costly disease that affects dairy farming globally, characterized by mammary gland inflammation. Bovine intramammary gland infection has been associated with more than 135 different pathogens of which Staphylococcus aureus is the main etiology of sub-clinical mastitis (SCM). The current study was designed to investigate the prevalence, antibiotic resistance pattern, and the presence of antibiotic resistance genes (mecA, tetK, aacA-aphD and blaZ) in S. aureus isolated from the raw milk of cows with subclinical mastitis. A total of 543 milk samples were collected from lactating cows such as Holstein Friesian (n = 79), Sahiwal (n = 175), Cholistani (n = 107), and Red Sindhi (n = 182) from different dairy farms in Pakistan. From the milk samples microscopic slides were prepared and the somatic cell count was assessed to find SCM. To isolate and identify S. aureus, milk was streaked on mannitol salt agar (MSA) plates. Further confirmation was done based on biochemical assays, including gram staining (+ coccus), catalase test (+), and coagulase test (+). All the biochemically confirmed S. aureus isolates were molecularly identified using the thermonuclease (nuc) gene. The antibiotic resistance pattern of all the S. aureus isolates was evaluated through the disc diffusion method. Out of 543 milk samples, 310 (57.09%) were positive for SCM. Among the SCM-positive samples, S. aureus was detected in 30.32% (94/310) samples. Out of 94 isolates, 47 (50%) were determined to be multidrug resistant (MDR). Among these MDR isolates, 11 exhibited resistance to Cefoxitin, and hence were classified as methicillin-resistant Staphylococcus aureus (MRSA). The S. aureus isolates showed the highest resistance to Lincomycin (84.04%) followed by Ampicillin (45.74%), while the least resistance was shown to Sulfamethoxazole/Trimethoprim (3.19%) and Gentamycin (6.38%). Polymerase chain reaction (PCR) analysis revealed that 55.31% of the isolates carried blaZ gene, 46.80% carried tetK gene, 17.02% harbored the mecA gene, whereas, aacA-aphD gene was found in 13.82% samples. Our findings revealed a significant level of contamination of milk with S. aureus and half (50%) of the isolates were MDR. The isolated S. aureus harbored various antibiotic resistance genes responsible for the absorbed phenotypic resistance. The alarmingly high prevalence of MDR S. aureus isolates and MRSA strains in these cases possess a serious risk to public health, emphasizes the urgent need to address this issue to protect both human and animal health in Pakistan.
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Affiliation(s)
- Ijaz Ul Haq
- College of Veterinary Sciences and Animal Husbandry, Abdul Wali Khan University Mardan, Mardan Pakistan
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Mustafa Kamal
- College of Veterinary Sciences and Animal Husbandry, Abdul Wali Khan University Mardan, Mardan Pakistan
- Department of Zoology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Ayman A. Swelum
- Department of Animal Production, College of Food and Agriculture Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Shehryar Khan
- College of Veterinary Sciences and Animal Husbandry, Abdul Wali Khan University Mardan, Mardan Pakistan
- Department of Biotechnology, Abdul Wali Khan University Mardan, Mardan, Pakistan
| | - Patricio R. De los Ríos-Escalante
- Facultad de Recursos Naturales, Departamento de Ciencias Biológicas y Químicas, Universidad Católica de Temuco, Temuco, Chile
- Nucleo de Estudios Ambientales UC Temuco, Temuco, Chile
| | - Tahir Usman
- College of Veterinary Sciences and Animal Husbandry, Abdul Wali Khan University Mardan, Mardan Pakistan
- Key Laboratory of Agricultural Animal Genetics and Breeding, National Engineering Laboratory for Animal Breeding, College of Animal Science and Technology, China Agricultural University, Beijing, China
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Winther AR, da Silva Duarte V, Porcellato D. Metataxonomic analysis and host proteome response in dairy cows with high and low somatic cell count: a quarter level investigation. Vet Res 2023; 54:32. [PMID: 37016420 PMCID: PMC10074679 DOI: 10.1186/s13567-023-01162-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 03/01/2023] [Indexed: 04/06/2023] Open
Abstract
Host response to invasive microbes in the bovine udder has an important role on the animal health and is essential to the dairy industry to ensure production of high-quality milk and reduce the mastitis incidence. To better understand the biology behind these host-microbiome interactions, we investigated the somatic cell proteomes at quarter level for four cows (collected before and after milking) using a shotgun proteomics approach. Simultaneously, we identified the quarter microbiota by amplicon sequencing to detect presence of mastitis pathogens or other commensal taxa. In total, 32 quarter milk samples were analyzed divided in two groups depending on the somatic cell count (SCC). The high SCC group (>100,000 cell/mL) included 10 samples and significant different proteome profiles were detected. Differential abundance analysis uncovers a specific expression pattern in high SCC samples revealing pathways involved in immune responses such as inflammation, activation of the complement system, migration of immune cells, and tight junctions. Interestingly, different proteome profiles were also identified in quarter samples containing one of the two mastitis pathogens, Staphylococcus aureus and Streptococcus uberis, indicating a different response of the host depending on the pathogen. Weighted correlation network analysis identified three modules of co-expressed proteins which were correlated with the SCC in the quarters. These modules contained proteins assigned to different aspects of the immune response, but also amino sugar and nucleotide sugar metabolism, and biosynthesis of amino acids. The results of this study provide deeper insights on how the proteome expression changes at quarter level in naturally infected cows and pinpoint potential interactions and important biological functions during host-microbe interaction.
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Affiliation(s)
- Anja Ruud Winther
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NMBU, Ås, Norway.
| | - Vinícius da Silva Duarte
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NMBU, Ås, Norway
| | - Davide Porcellato
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NMBU, Ås, Norway
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Models versus pathogens: how conserved is the FtsZ in bacteria? Biosci Rep 2023; 43:232502. [PMID: 36695643 PMCID: PMC9939409 DOI: 10.1042/bsr20221664] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/10/2023] [Accepted: 01/25/2023] [Indexed: 01/26/2023] Open
Abstract
Combating anti-microbial resistance by developing alternative strategies is the need of the hour. Cell division, particularly FtsZ, is being extensively studied for its potential as an alternative target for anti-bacterial therapy. Bacillus subtilis and Escherichia coli are the two well-studied models for research on FtsZ, the leader protein of the cell division machinery. As representatives of gram-positive and gram-negative bacteria, respectively, these organisms have provided an extensive outlook into the process of cell division in rod-shaped bacteria. However, research on other shapes of bacteria, like cocci and ovococci, lags behind that of model rods. Even though most regions of FtsZ show sequence and structural conservation throughout bacteria, the differences in FtsZ functioning and interacting partners establish several different modes of division in different bacteria. In this review, we compare the features of FtsZ and cell division in the model rods B. subtilis and E. coli and the four pathogens: Staphylococcus aureus, Streptococcus pneumoniae, Mycobacterium tuberculosis, and Pseudomonas aeruginosa. Reviewing several recent articles on these pathogenic bacteria, we have highlighted the functioning of FtsZ, the unique roles of FtsZ-associated proteins, and the cell division processes in them. Further, we provide a detailed look at the anti-FtsZ compounds discovered and their target bacteria, emphasizing the need for elucidation of the anti-FtsZ mechanism of action in different bacteria. Current challenges and opportunities in the ongoing journey of identifying potent anti-FtsZ drugs have also been described.
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Barbuti MD, Myrbråten IS, Morales Angeles D, Kjos M. The cell cycle of Staphylococcus aureus: An updated review. Microbiologyopen 2022; 12:e1338. [PMID: 36825883 PMCID: PMC9733580 DOI: 10.1002/mbo3.1338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/29/2022] [Accepted: 11/29/2022] [Indexed: 12/13/2022] Open
Abstract
As bacteria proliferate, DNA replication, chromosome segregation, cell wall synthesis, and cytokinesis occur concomitantly and need to be tightly regulated and coordinated. Although these cell cycle processes have been studied for decades, several mechanisms remain elusive, specifically in coccus-shaped cells such as Staphylococcus aureus. In recent years, major progress has been made in our understanding of how staphylococci divide, including new, fundamental insights into the mechanisms of cell wall synthesis and division site selection. Furthermore, several novel proteins and mechanisms involved in the regulation of replication initiation or progression of the cell cycle have been identified and partially characterized. In this review, we will summarize our current understanding of the cell cycle processes in the spheroid model bacterium S. aureus, with a focus on recent advances in the understanding of how these processes are regulated.
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Affiliation(s)
- Maria D. Barbuti
- Faculty of Chemistry, Biotechnology and Food ScienceNorwegian University of Life Sciences (NMBU)ÅsNorway
| | - Ine S. Myrbråten
- Faculty of Chemistry, Biotechnology and Food ScienceNorwegian University of Life Sciences (NMBU)ÅsNorway
| | - Danae Morales Angeles
- Faculty of Chemistry, Biotechnology and Food ScienceNorwegian University of Life Sciences (NMBU)ÅsNorway
| | - Morten Kjos
- Faculty of Chemistry, Biotechnology and Food ScienceNorwegian University of Life Sciences (NMBU)ÅsNorway
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Finding New Fundamental Pieces for the Bacterial Cell Division Puzzle. mBio 2022; 13:e0073722. [PMID: 35735744 PMCID: PMC9426480 DOI: 10.1128/mbio.00737-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The division of bacterial cells into two daughter cells requires a precise balance of more than a dozen highly conserved proteins that coordinate chromosome segregation with the synthesis of the novel cell envelope. The paradigms of cell division were established in rod-shaped bacteria and this fundamental process is far less characterized in spherical bacteria. In a search for novel, essential cell division proteins in Staphylococci, Myrbråten et al. used combined depletion and subcellular localization analyses to identify the staphylococcal morphology determinant, SmdA, that is exclusively found in cocci. Knockdown of smdA results in severe division defects and increased sensitivity to cell wall targeting antibiotics. Although determining the precise role of SmdA in S. aureus cell division will require further research, this study provides a striking example of how researchers can assign functions to genes that are too fundamental to cell biology to allow genetic inactivation.
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