scholarly journals Bypassing the Restriction System To Improve Transformation of Staphylococcus epidermidis

2017 ◽  
Vol 199 (16) ◽  
Author(s):  
Stephen K. Costa ◽  
Niles P. Donegan ◽  
Anna-Rita Corvaglia ◽  
Patrice François ◽  
Ambrose L. Cheung

ABSTRACT Staphylococcus epidermidis is the leading cause of infections on indwelling medical devices worldwide. Intrinsic antibiotic resistance and vigorous biofilm production have rendered these infections difficult to treat and, in some cases, require the removal of the offending medical prosthesis. With the exception of two widely passaged isolates, RP62A and 1457, the pathogenesis of infections caused by clinical S. epidermidis strains is poorly understood due to the strong genetic barrier that precludes the efficient transformation of foreign DNA into clinical isolates. The difficulty in transforming clinical S. epidermidis isolates is primarily due to the type I and IV restriction-modification systems, which act as genetic barriers. Here, we show that efficient plasmid transformation of clinical S. epidermidis isolates from clonal complexes 2, 10, and 89 can be realized by employing a plasmid artificial modification (PAM) in Escherichia coli DC10B containing a Δdcm mutation. This transformative technique should facilitate our ability to genetically modify clinical isolates of S. epidermidis and hence improve our understanding of their pathogenesis in human infections. IMPORTANCE Staphylococcus epidermidis is a source of considerable morbidity worldwide. The underlying mechanisms contributing to the commensal and pathogenic lifestyles of S. epidermidis are poorly understood. Genetic manipulations of clinically relevant strains of S. epidermidis are largely prohibited due to the presence of a strong restriction barrier. With the introductions of the tools presented here, genetic manipulation of clinically relevant S. epidermidis isolates has now become possible, thus improving our understanding of S. epidermidis as a pathogen.

mBio ◽  
2012 ◽  
Vol 3 (2) ◽  
Author(s):  
Ian R. Monk ◽  
Ishita M. Shah ◽  
Min Xu ◽  
Man-Wah Tan ◽  
Timothy J. Foster

ABSTRACTThe strong restriction barrier present inStaphylococcus aureusandStaphylococcus epidermidishas limited functional genomic analysis to a small subset of strains that are amenable to genetic manipulation. Recently, a conserved type IV restriction system termed SauUSI (which specifically recognizes cytosine methylated DNA) was identified as the major barrier to transformation with foreign DNA. Here we have independently corroborated these findings in a widely used laboratory strain ofS. aureus. Additionally, we have constructed a DNA cytosine methyltransferase mutant in the high-efficiencyEscherichia colicloning strain DH10B (called DC10B). Plasmids isolated from DC10B can be directly transformed into clinical isolates ofS. aureusandS. epidermidis. We also show that the loss of restriction (both type I and IV) in anS. aureusUSA300 strain does not have an impact on virulence. Circumventing the SauUSI restriction barrier, combined with an improved deletion and transformation protocol, has allowed the genetic manipulation of previously untransformable strains of these important opportunistic pathogens.IMPORTANCEStaphylococcal infections place a huge burden on the health care sector due both to their severity and also to the economic impact of treating the infections because of prolonged hospitalization. To improve the understanding ofStaphylococcus aureusandStaphylococcus epidermidisinfections, we have developed a series of improved techniques that allow the genetic manipulation of strains that were previously refractory to transformation. These developments will speed up the process of mutant construction and increase our understanding of these species as a whole, rather than just a small subset of strains that could previously be manipulated.


mBio ◽  
2019 ◽  
Vol 10 (6) ◽  
Author(s):  
Jean Y. H. Lee ◽  
Glen P. Carter ◽  
Sacha J. Pidot ◽  
Romain Guérillot ◽  
Torsten Seemann ◽  
...  

ABSTRACT Staphylococcus epidermidis is a significant opportunistic pathogen of humans. Molecular studies in this species have been hampered by the presence of restriction-modification (RM) systems that limit introduction of foreign DNA. Here, we establish the complete genomes and methylomes for seven clinically significant, genetically diverse S. epidermidis isolates and perform the first systematic genomic analyses of the type I RM systems within both S. epidermidis and Staphylococcus aureus. Our analyses revealed marked differences in the gene arrangement, chromosomal location, and movement of type I RM systems between the two species. Unlike S. aureus, S. epidermidis type I RM systems demonstrate extensive diversity even within a single genetic lineage. This is contrary to current assumptions and has important implications for approaching the genetic manipulation of S. epidermidis. Using Escherichia coli plasmid artificial modification (PAM) to express S. epidermidis hsdMS, we readily overcame restriction barriers in S. epidermidis and achieved electroporation efficiencies equivalent to those of modification-deficient mutants. With these functional experiments, we demonstrated how genomic data can be used to predict both the functionality of type I RM systems and the potential for a strain to be electroporation proficient. We outline an efficient approach for the genetic manipulation of S. epidermidis strains from diverse genetic backgrounds, including those that have hitherto been intractable. Additionally, we identified S. epidermidis BPH0736, a naturally restriction-defective, clinically significant, multidrug-resistant ST2 isolate, as an ideal candidate for molecular studies. IMPORTANCE Staphylococcus epidermidis is a major cause of hospital-acquired infections, especially those related to implanted medical devices. Understanding how S. epidermidis causes disease and devising ways to combat these infections have been hindered by an inability to genetically manipulate clinically significant hospital-adapted strains. Here, we provide the first comprehensive analyses of the barriers to the uptake of foreign DNA in S. epidermidis and demonstrate that these are distinct from those described for S. aureus. Using these insights, we demonstrate an efficient approach for the genetic manipulation of S. epidermidis to enable the study of clinical isolates for the first time.


2015 ◽  
Vol 81 (7) ◽  
pp. 2481-2488 ◽  
Author(s):  
Volker Winstel ◽  
Petra Kühner ◽  
Bernhard Krismer ◽  
Andreas Peschel ◽  
Holger Rohde

ABSTRACTGenetic manipulation of emerging bacterial pathogens, such as coagulase-negative staphylococci (CoNS), is a major hurdle in clinical and basic microbiological research. Strong genetic barriers, such as restriction modification systems or clustered regularly interspaced short palindromic repeats (CRISPR), usually interfere with available techniques for DNA transformation and therefore complicate manipulation of CoNS or render it impossible. Thus, current knowledge of pathogenicity and virulence determinants of CoNS is very limited. Here, a rapid, efficient, and highly reliable technique is presented to transfer plasmid DNA essential for genetic engineering to important CoNS pathogens from a uniqueStaphylococcus aureusstrain via a specificS. aureusbacteriophage, Φ187. Even strains refractory to electroporation can be transduced by this technique once donor and recipient strains share similar Φ187 receptor properties. As a proof of principle, this technique was used to delete the alternative transcription factor sigma B (SigB) via allelic replacement in nasal and clinicalStaphylococcus epidermidisisolates at high efficiencies. The described approach will allow the genetic manipulation of a wide range of CoNS pathogens and might inspire research activities to manipulate other important pathogens in a similar fashion.


mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Srishtee Arora ◽  
Xiqi Li ◽  
Andrew Hillhouse ◽  
Kranti Konganti ◽  
Sara V. Little ◽  
...  

ABSTRACT Staphylococcus epidermidis is a leading cause of nosocomial infections in patients with a compromised immune system and/or an implanted medical device. Seventy to 90% of S. epidermidis clinical isolates are methicillin resistant and carry the mecA gene, present in a mobile genetic element (MGE) called the staphylococcal cassette chromosome mec (SCCmec) element. Along with the presence of antibiotic and heavy metal resistance genes, MGEs can also contain genes encoding secreted or cell wall-anchored virulence factors. In our earlier studies of S. epidermidis clinical isolates, we discovered S. epidermidis surface protein J (SesJ), a prototype of a recently discovered subfamily of the microbial surface component recognizing adhesive matrix molecule (MSCRAMM) group. MSCRAMMs are major virulence factors of pathogenic Gram-positive bacteria. Here, we report that the sesJ gene is always accompanied by two glycosyltransferase genes, gtfA and gtfB, and is present in two MGEs, called the arginine catabolic mobile element (ACME) and the staphylococcal cassette chromosome (SCC) element. The presence of the sesJ gene was associated with the left-hand direct repeat DR_B or DR_E. When inserted via DR_E, the sesJ gene was encoded in the SCC element. When inserted via DR_B, the sesJ gene was accompanied by the genes for the type 1 restriction modification system and was encoded in the ACME. Additionally, the SCC element and ACME carry different isoforms of the SesJ protein. To date, the genes encoding MSCRAMMs have been seen to be located in the bacterial core genome. Here, we report the presence of an MSCRAMM in an MGE in S. epidermidis clinical isolates. IMPORTANCE S. epidermidis is an opportunistic bacterium that has established itself as a successful nosocomial pathogen. The modern era of novel therapeutics and medical devices has extended the longevity of human life, but at the same time, we also witness the evolution of pathogens to adapt to newly available niches in the host. Increasing antibiotic resistance among pathogens provides an example of such pathogen adaptation. With limited opportunities to modify the core genome, most of the adaptation occurs by acquiring new genes, such as virulence factors and antibiotic resistance determinants present in MGEs. In this study, we describe that the sesJ gene, encoding a recently discovered cell wall-anchored protein in S. epidermidis, is present in both ACME and the SCC element. The presence of virulence factors in MGEs can influence the virulence potential of a specific strain. Therefore, it is critical to study the virulence factors found in MGEs in emerging pathogenic bacteria or strains to understand the mechanisms used by these bacteria to cause infections.


mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
Ian R. Monk ◽  
Jai J. Tree ◽  
Benjamin P. Howden ◽  
Timothy P. Stinear ◽  
Timothy J. Foster

ABSTRACTStaphylococcus aureusis a prominent global nosocomial and community-acquired bacterial pathogen. A strong restriction barrier presents a major hurdle for the introduction of recombinant DNA into clinical isolates ofS. aureus. Here, we describe the construction and characterization of the IMXXB series ofEscherichia colistrains that mimic the type I adenine methylation profiles ofS. aureusclonal complexes 1, 8, 30, and ST93. The IMXXB strains enable direct, high-efficiency transformation and streamlined genetic manipulation of majorS. aureuslineages.IMPORTANCEThe genetic manipulation of clinicalS. aureusisolates has been hampered due to the presence of restriction modification barriers that detect and subsequently degrade inappropriately methylated DNA. Current methods allow the introduction of plasmid DNA into a limited subset ofS. aureusstrains at high efficiency after passage of plasmid DNA through the restriction-negative, modification-proficient strain RN4220. Here, we have constructed and validated a suite ofE. colistrains that mimic the adenine methylation profiles of different clonal complexes and show high-efficiency plasmid DNA transfer. The ability to bypass RN4220 will reduce the cost and time involved for plasmid transfer intoS. aureus. The IMXXB series ofE. colistrains should expedite the process of mutant construction in diverse genetic backgrounds and allow the application of new techniques to the genetic manipulation ofS. aureus.


2017 ◽  
Vol 5 (22) ◽  
Author(s):  
Madeline R. Galac ◽  
Jason Stam ◽  
Rosslyn Maybank ◽  
Mary Hinkle ◽  
Dietrich Mack ◽  
...  

ABSTRACT Staphylococcus epidermidis 1457 is a frequently utilized strain that is amenable to genetic manipulation and has been widely used for biofilm-related research. We report here the whole-genome sequence of this strain, which encodes 2,277 protein-coding genes and 81 RNAs within its 2.4-Mb genome and plasmid.


2011 ◽  
Vol 55 (5) ◽  
pp. 1896-1905 ◽  
Author(s):  
Anna C. Shore ◽  
Angela S. Rossney ◽  
Orla M. Brennan ◽  
Peter M. Kinnevey ◽  
Hilary Humphreys ◽  
...  

ABSTRACTThe arginine catabolic mobile element (ACME) is prevalent among methicillin-resistantStaphylococcus aureus(MRSA) isolates of sequence type 8 (ST8) and staphylococcal chromosomal cassettemec(SCCmec) type IVa (USA300) (ST8-MRSA-IVa isolates), and evidence suggests that ACME enhances the ability of ST8-MRSA-IVa to grow and survive on its host. ACME has been identified in a small number of isolates belonging to other MRSA clones but is widespread among coagulase-negative staphylococci (CoNS). This study reports the first description of ACME in two distinct strains of the pandemic ST22-MRSA-IV clone. A total of 238 MRSA isolates recovered in Ireland between 1971 and 2008 were investigated for ACME using a DNA microarray. Twenty-three isolates (9.7%) were ACME positive, and all were either MRSA genotype ST8-MRSA-IVa (7/23, 30%) or MRSA genotype ST22-MRSA-IV (16/23, 70%). Whole-genome sequencing and comprehensive molecular characterization revealed the presence of a novel 46-kb ACME and staphylococcal chromosomal cassettemec(SCCmec) composite island (ACME/SCCmec-CI) in ST22-MRSA-IVh isolates (n= 15). This ACME/SCCmec-CI consists of a 12-kb DNA region previously identified in ACME type II inS. epidermidisATCC 12228, a truncated copy of the J1 region of SCCmectype I, and a complete SCCmectype IVh element. The composite island has a novel genetic organization, with ACME located withinorfXand SCCmeclocated downstream of ACME. One PVL locus-positive ST22-MRSA-IVa isolate carried ACME located downstream of SCCmectype IVa, as previously described in ST8-MRSA-IVa. These results suggest that ACME has been acquired by ST22-MRSA-IV on two independent occasions. At least one of these instances may have involved horizontal transfer and recombination events between MRSA and CoNS. The presence of ACME may enhance dissemination of ST22-MRSA-IV, an already successful MRSA clone.


2019 ◽  
Author(s):  
Jean YH Lee ◽  
Glen P Carter ◽  
Sacha J Pidot ◽  
Romain Guérillot ◽  
Torsten Seemann ◽  
...  

AbstractStaphylococcus epidermidis is a significant opportunistic pathogen of humans. Molecular studies in this species have been hampered by the presence of restriction-modification (RM) systems that limit introduction of foreign DNA. Here we establish the complete genomes and methylomes for seven clinically significant, genetically diverse S. epidermidis isolates and perform the first systematic genomic analyses of the type I RM systems within both S. epidermidis and Staphylococcus aureus. Our analyses revealed marked differences in the gene arrangement, chromosomal location and movement of type I RM systems between the two species. Unlike S. aureus, S. epidermidis type I RM systems demonstrate extensive diversity even within a single genetic lineage. This is contrary to current assumptions and has important implications for approaching the genetic manipulation of S. epidermidis. Using Escherichia coli plasmid artificial modification (PAM) to express S. epidermidis hsdMS, we readily overcame restriction barriers in S. epidermidis, and achieved transformation efficiencies equivalent to those of modification deficient mutants. With these functional experiments we demonstrate how genomic data can be used to predict both the functionality of type I RM systems and the potential for a strain to be transformation proficient. We outline an efficient approach for the genetic manipulation of S. epidermidis from diverse genetic backgrounds, including those that have hitherto been intractable. Additionally, we identified S. epidermidis BPH0736, a naturally restriction defective, clinically significant, multidrug-resistant ST2 isolate as an ideal candidate for molecular studies.ImportanceStaphylococcus epidermidis is a major cause of hospital-acquired infections, especially those related to implanted medical devices. Understanding how S. epidermidis causes disease and devising ways to combat these infections has been hindered by an inability to genetically manipulate “hospital-adapted” strains that cause clinical disease. Here we provide the first comprehensive analyses of the mechanisms whereby S. epidermidis resists the uptake of foreign DNA and demonstrate that these are distinct from those described for S. aureus. Until now it had been assumed that these are the same. Using these insights, we demonstrate an efficient approach for the genetic manipulation of S. epidermidis to enable the study of clinically relevant isolates for the first time.


2014 ◽  
Vol 81 (5) ◽  
pp. 1775-1781 ◽  
Author(s):  
Aaron W. Puri ◽  
Sarah Owen ◽  
Frances Chu ◽  
Ted Chavkin ◽  
David A. C. Beck ◽  
...  

ABSTRACTAerobic methanotrophs oxidize methane at ambient temperatures and pressures and are therefore attractive systems for methane-based bioconversions. In this work, we developed and validated genetic tools forMethylomicrobium buryatense, a haloalkaliphilic gammaproteobacterial (type I) methanotroph.M. buryatensewas isolated directly on natural gas and grows robustly in pure culture with a 3-h doubling time, enabling rapid genetic manipulation compared to many other methanotrophic species. As a proof of concept, we used a sucrose counterselection system to eliminate glycogen production inM. buryatenseby constructing unmarked deletions in two redundant glycogen synthase genes. We also selected for a more genetically tractable variant strain that can be conjugated with small incompatibility group P (IncP)-based broad-host-range vectors and determined that this capability is due to loss of the native plasmid. These tools makeM. buryatensea promising model system for studying aerobic methanotroph physiology and enable metabolic engineering in this bacterium for industrial biocatalysis of methane.


2016 ◽  
Vol 82 (7) ◽  
pp. 2062-2069 ◽  
Author(s):  
Xin Yan ◽  
Frances Chu ◽  
Aaron W. Puri ◽  
Yanfen Fu ◽  
Mary E. Lidstrom

ABSTRACTMethane is becoming a major candidate for a prominent carbon feedstock in the future, and the bioconversion of methane into valuable products has drawn increasing attention. To facilitate the use of methanotrophic organisms as industrial strains and accelerate our ability to metabolically engineer methanotrophs, simple and rapid genetic tools are needed. Electroporation is one such enabling tool, but to date it has not been successful in a group of methanotrophs of interest for the production of chemicals and fuels, the gammaproteobacterial (type I) methanotrophs. In this study, we developed electroporation techniques with a high transformation efficiency for three different type I methanotrophs:Methylomicrobium buryatense5GB1C,Methylomonassp. strain LW13, andMethylobactertundripaludum21/22. We further developed this technique inM. buryatense, a haloalkaliphilic aerobic methanotroph that demonstrates robust growth with a high carbon conversion efficiency and is well suited for industrial use for the bioconversion of methane. On the basis of the high transformation efficiency ofM. buryatense, gene knockouts or integration of a foreign fragment into the chromosome can be easily achieved by direct electroporation of PCR-generated deletion or integration constructs. Moreover, site-specific recombination (FLP-FRT [FLP recombination target] recombination) andsacBcounterselection systems were employed to perform marker-free manipulation, and two new antibiotics, zeocin and hygromycin, were validated to be antibiotic markers in this strain. Together, these tools facilitate the rapid genetic manipulation ofM. buryatenseand other type I methanotrophs, promoting the ability to perform fundamental research and industrial process development with these strains.


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