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Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

Ostria-Hernández ML, Sánchez-Vallejo CJ, Ibarra JA, Castro-Escarpulli G - BMC Res Notes (2015)

Bottom Line: The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different.BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences.The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in metabolism and resistance to antibiotics.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Bacteriología Médica y, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Colonia Santo Tomás, Delegación Miguel Hidalgo, CP 11340, Mexico, D.F., Mexico. marthal_19@yahoo.com.mx.

ABSTRACT

Background: In recent years the emergence of multidrug resistant Klebsiella pneumoniae strains has been an increasingly common event. This opportunistic species is one of the five main bacterial pathogens that cause hospital infections worldwide and multidrug resistance has been associated with the presence of high molecular weight plasmids. Plasmids are generally acquired through horizontal transfer and therefore is possible that systems that prevent the entry of foreign genetic material are inactive or absent. One of these systems is CRISPR/Cas. However, little is known regarding the clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) system in K. pneumoniae. The adaptive immune system CRISPR/Cas has been shown to limit the entry of foreign genetic elements into bacterial organisms and in some bacteria it has been shown to be involved in regulation of virulence genes. Thus in this work we used bioinformatics tools to determine the presence or absence of CRISPR/Cas systems in available K. pneumoniae genomes.

Results: The complete CRISPR/Cas system was identified in two out of the eight complete K. pneumoniae genomes sequences and in four out of the 44 available draft genomes sequences. The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different. As for the CRISPR sequences, the average lengths of the direct repeats and spacers were 29 and 33 bp, respectively. BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences. The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in metabolism and resistance to antibiotics.

Conclusions: The CRISPR/Cas system is not widely distributed in K. pneumoniae genomes, those present most likely belong to type I-E with few differences from the arrangement of the cse3 gene and most of the spacers have not been are not described yet. Given that the CRISPR/Cas system is scarcely distributed among K. pneumoniae genomes it is not clear whether it is involved in either immunity against foreign genetic material or virulence. We consider that this study represents a first step to understand the role of CRISPR/Cas in K. pneumoniae.

No MeSH data available.


Related in: MedlinePlus

Genomic context of the CRISPR/Cas system in diverse strains of Klebsiella pneumoniae.a Genomic context of cas operon. Enzymes related to bacterial metabolism and some antibiotic resistance genes are located in the vicinity of cas operon. b CRISPR/Cas organization. The cas operon consists of eight genes and the CRISPR sequences are located downstream from cas2 and upstream from cas3 in those genomes containing two CRISPR arrays.
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Fig2: Genomic context of the CRISPR/Cas system in diverse strains of Klebsiella pneumoniae.a Genomic context of cas operon. Enzymes related to bacterial metabolism and some antibiotic resistance genes are located in the vicinity of cas operon. b CRISPR/Cas organization. The cas operon consists of eight genes and the CRISPR sequences are located downstream from cas2 and upstream from cas3 in those genomes containing two CRISPR arrays.

Mentions: When analyzing the region upstream of the CRISPR/Cas we observed that genes were identical and encode for different subunits of an ABC type transporter (ID: AFQ65464, AFQ65465, AFQ65466), multiple subunits of a formate dehydrogenase (ID: AFQ65461), malate dehydrogenase (ID: AFQ65462), and amino acid transporters (ID: AFQ65453, AFQ65454, AFQ65460). Interestingly, we also found genes that seem to code proteins for antimicrobial resistance such as glyoxalase and efflux pumps (MdtM, multidrug efflux system protein) (ID: AFQ65457, AFQ65459, EMH97621). On the other hand, and similarly that observed at the 5′ end, at the 3′ end of the CRISPR/Cas region there was no variability. This region contains genes related to antibiotic resistance, such as lactoylglutathione lyase (or glyoxalase, which confers resistance to bleomycin) (ID: AFQ65478), and genes encoding different subunits of proteins involved in cell metabolism, such as 2-gluconate dehydrogenase (ID: AFQ65479, AFQ65480, AFQ65481), heme protein exporters (ID: BAH63785, BAH63784), and proteins involved in the biogenesis of cytochrome C (ID: AFQ63377, AFQ63378, AFQ65482, AFQ65483, AFQ65484, AFQ65485, AFQ65486, AFQ65487, AFQ65488) (Fig. 2a). In the draft genomes, most of the genes are annotated as hypothetical; however, a detailed analysis of this region reveals that the size and sequence of the genes is similar amongst all genomes with these systems. Taken together our analysis demonstrated that those K. pneumoniae strains harboring a CRISPR/Cas system are syntenic.


Survey of clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) systems in multiple sequenced strains of Klebsiella pneumoniae.

Ostria-Hernández ML, Sánchez-Vallejo CJ, Ibarra JA, Castro-Escarpulli G - BMC Res Notes (2015)

Genomic context of the CRISPR/Cas system in diverse strains of Klebsiella pneumoniae.a Genomic context of cas operon. Enzymes related to bacterial metabolism and some antibiotic resistance genes are located in the vicinity of cas operon. b CRISPR/Cas organization. The cas operon consists of eight genes and the CRISPR sequences are located downstream from cas2 and upstream from cas3 in those genomes containing two CRISPR arrays.
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4522967&req=5

Fig2: Genomic context of the CRISPR/Cas system in diverse strains of Klebsiella pneumoniae.a Genomic context of cas operon. Enzymes related to bacterial metabolism and some antibiotic resistance genes are located in the vicinity of cas operon. b CRISPR/Cas organization. The cas operon consists of eight genes and the CRISPR sequences are located downstream from cas2 and upstream from cas3 in those genomes containing two CRISPR arrays.
Mentions: When analyzing the region upstream of the CRISPR/Cas we observed that genes were identical and encode for different subunits of an ABC type transporter (ID: AFQ65464, AFQ65465, AFQ65466), multiple subunits of a formate dehydrogenase (ID: AFQ65461), malate dehydrogenase (ID: AFQ65462), and amino acid transporters (ID: AFQ65453, AFQ65454, AFQ65460). Interestingly, we also found genes that seem to code proteins for antimicrobial resistance such as glyoxalase and efflux pumps (MdtM, multidrug efflux system protein) (ID: AFQ65457, AFQ65459, EMH97621). On the other hand, and similarly that observed at the 5′ end, at the 3′ end of the CRISPR/Cas region there was no variability. This region contains genes related to antibiotic resistance, such as lactoylglutathione lyase (or glyoxalase, which confers resistance to bleomycin) (ID: AFQ65478), and genes encoding different subunits of proteins involved in cell metabolism, such as 2-gluconate dehydrogenase (ID: AFQ65479, AFQ65480, AFQ65481), heme protein exporters (ID: BAH63785, BAH63784), and proteins involved in the biogenesis of cytochrome C (ID: AFQ63377, AFQ63378, AFQ65482, AFQ65483, AFQ65484, AFQ65485, AFQ65486, AFQ65487, AFQ65488) (Fig. 2a). In the draft genomes, most of the genes are annotated as hypothetical; however, a detailed analysis of this region reveals that the size and sequence of the genes is similar amongst all genomes with these systems. Taken together our analysis demonstrated that those K. pneumoniae strains harboring a CRISPR/Cas system are syntenic.

Bottom Line: The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different.BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences.The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in metabolism and resistance to antibiotics.

View Article: PubMed Central - PubMed

Affiliation: Laboratorio de Bacteriología Médica y, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Prolongación de Carpio y Plan de Ayala S/N, Colonia Santo Tomás, Delegación Miguel Hidalgo, CP 11340, Mexico, D.F., Mexico. marthal_19@yahoo.com.mx.

ABSTRACT

Background: In recent years the emergence of multidrug resistant Klebsiella pneumoniae strains has been an increasingly common event. This opportunistic species is one of the five main bacterial pathogens that cause hospital infections worldwide and multidrug resistance has been associated with the presence of high molecular weight plasmids. Plasmids are generally acquired through horizontal transfer and therefore is possible that systems that prevent the entry of foreign genetic material are inactive or absent. One of these systems is CRISPR/Cas. However, little is known regarding the clustered regularly interspaced short palindromic repeats and their associated Cas proteins (CRISPR/Cas) system in K. pneumoniae. The adaptive immune system CRISPR/Cas has been shown to limit the entry of foreign genetic elements into bacterial organisms and in some bacteria it has been shown to be involved in regulation of virulence genes. Thus in this work we used bioinformatics tools to determine the presence or absence of CRISPR/Cas systems in available K. pneumoniae genomes.

Results: The complete CRISPR/Cas system was identified in two out of the eight complete K. pneumoniae genomes sequences and in four out of the 44 available draft genomes sequences. The cas genes in these strains comprises eight cas genes similar to those found in Escherichia coli, suggesting they belong to the type I-E group, although their arrangement is slightly different. As for the CRISPR sequences, the average lengths of the direct repeats and spacers were 29 and 33 bp, respectively. BLAST searches demonstrated that 38 of the 116 spacer sequences (33%) are significantly similar to either plasmid, phage or genome sequences, while the remaining 78 sequences (67%) showed no significant similarity to other sequences. The region where the CRISPR/Cas systems were located is the same in all the Klebsiella genomes containing it, it has a syntenic architecture, and is located among genes encoding for proteins likely involved in metabolism and resistance to antibiotics.

Conclusions: The CRISPR/Cas system is not widely distributed in K. pneumoniae genomes, those present most likely belong to type I-E with few differences from the arrangement of the cse3 gene and most of the spacers have not been are not described yet. Given that the CRISPR/Cas system is scarcely distributed among K. pneumoniae genomes it is not clear whether it is involved in either immunity against foreign genetic material or virulence. We consider that this study represents a first step to understand the role of CRISPR/Cas in K. pneumoniae.

No MeSH data available.


Related in: MedlinePlus