scholarly journals Molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolates with focus on antimicrobial resistance

2019 ◽  
Author(s):  
Xiaoling Yu ◽  
Wen Zhang ◽  
Zhiping Zhao ◽  
Chengsong Ye ◽  
Shuyan Zhou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Snp Markers ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Resistance ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Medical University

Abstract Ba ckgrou nd The enhancing incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP)-mediated infections in Mengchao Hepatobiliary Hospital of Fujian Medical University in 2017 is the motivation behind this investigation to study gene phenotypes and resistance-associated genes of emergence regarding the CRKP strains. In current study, seven inpatients are enrolled in the hospital with complete treatments. The carbapenem-resistant K. pneumoniae whole genome is sequenced using MiSeq short-read and Oxford Nanopore long-read sequencing technology. Prophages are identified to assess genetic diversity within CRKP genomes. Results The investigation encompassed eight CRKP strains that collected from the patients enrolled as well as the environment, which illustrate that bla KPC-2 is responsible for phenotypic resistance in six CRKP strains that K . pneumoniae sequence type (ST11) is informed. The plasmid with IncR, ColRNAI and pMLST type with IncF[F33:A-:B-] co-exist in all ST11 with KPC-2-producing CRKP strains. Along with carbapenemases, all K. pneumoniae strains harbor two or three extended spectrum β-lactamase (ESBL)-producing genes. f osA gene is detected amongst all the CRKP strains. The single nucleotide polymorphisms (SNP) markers are indicated and validated among all CRKP strains, providing valuable clues for distinguishing carbapenem-resistant strains from conventional K. pneumoniae . Co nclusions ST11 is the main CRKP type, and bla KPC-2 is the dominant carbapenemase gene harbored by clinical CRKP isolates from current investigations. The SNP markers detected would be helpful for characterizing CRKP strain from general K. pneumoniae. The data provides insights into effective strategy developments for controlling CRKP and nosocomial infection reductions.

scholarly journals Molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolates with focus on antimicrobial resistance

BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Xiaoling Yu ◽  
Wen Zhang ◽  
Zhiping Zhao ◽  
Chengsong Ye ◽  
Shuyan Zhou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Snp Markers ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Resistance ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Medical University

Abstract Background The enhancing incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP)-mediated infections in Mengchao Hepatobiliary Hospital of Fujian Medical University in 2017 is the motivation behind this investigation to study gene phenotypes and resistance-associated genes of emergence regarding the CRKP strains. In current study, seven inpatients are enrolled in the hospital with complete treatments. The carbapenem-resistant K. pneumoniae whole genome is sequenced using MiSeq short-read and Oxford Nanopore long-read sequencing technology. Prophages are identified to assess genetic diversity within CRKP genomes. Results The investigation encompassed eight CRKP strains that collected from the patients enrolled as well as the environment, which illustrate that blaKPC-2 is responsible for phenotypic resistance in six CRKP strains that K. pneumoniae sequence type (ST11) is informed. The plasmid with IncR, ColRNAI and pMLST type with IncF[F33:A-:B-] co-exist in all ST11 with KPC-2-producing CRKP strains. Along with carbapenemases, all K. pneumoniae strains harbor two or three extended spectrum β-lactamase (ESBL)-producing genes. fosA gene is detected amongst all the CRKP strains. The single nucleotide polymorphisms (SNP) markers are indicated and validated among all CRKP strains, providing valuable clues for distinguishing carbapenem-resistant strains from conventional K. pneumoniae. Conclusions ST11 is the main CRKP type, and blaKPC-2 is the dominant carbapenemase gene harbored by clinical CRKP isolates from current investigations. The SNP markers detected would be helpful for characterizing CRKP strain from general K. pneumoniae. The data provides insights into effective strategy developments for controlling CRKP and nosocomial infection reductions.

scholarly journals Molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolates with focus on antimicrobial resistance

2019 ◽  
Author(s):  
Xiaoling Yu ◽  
Wen Zhang ◽  
Zhiping Zhao ◽  
Chengsong Ye ◽  
Shuyan Zhou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Snp Markers ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Resistance ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Medical University

Abstract Background The enhancing incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP)-mediated infections in Mengchao Hepatobiliary Hospital of Fujian Medical University in 2017 is the motivation behind this investigation to study gene phenotypes and resistance-associated genes of emergence regarding the CRKP strains. In current study, seven inpatients are enrolled in the hospital with complete treatments. The carbapenem-resistant K. pneumoniae whole genome is sequenced using MiSeq short-read and Oxford Nanopore long-read sequencing technology. Prophages are identified to assess genetic diversity within CRKP genomes. Results The investigation encompassed eight CRKP strains that collected from the patients enrolled as well as the environment, which illustrate that blaKPC-2 is responsible for phenotypic resistance in six CRKP strains that K. pneumoniae sequence type (ST11) is informed. The plasmid with IncR, ColRNAI and pMLST type with IncF[F33:A-:B-] co-exist in all ST11 with KPC-2-producing CRKP strains. Along with carbapenemases, all K. pneumoniae strains harbor two or three extended spectrum β-lactamase (ESBL)-producing genes. fosA gene is detected amongst all the CRKP strains. The single nucleotide polymorphisms (SNP) markers are indicated and validated among all CRKP strains, providing valuable clues for distinguishing carbapenem-resistant strains from conventional K. pneumoniae. Conclusions ST11 is the main CRKP type, and blaKPC-2 is the dominant carbapenemase gene harbored by clinical CRKP isolates from current investigations. The SNP markers detected would be helpful for characterizing CRKP strain from general K. pneumoniae. The data provides insights into effective strategy developments for controlling CRKP and nosocomial infection reductions.

scholarly journals Molecular characterization of carbapenem-resistant Klebsiella pneumoniae isolates with focus on antimicrobial resistance

2019 ◽  
Author(s):  
Xiaoling Yu ◽  
Wen Zhang ◽  
Zhiping Zhao ◽  
Chengsong Ye ◽  
Shuyan Zhou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Snp Markers ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Resistance ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Medical University

AbstractThe enhancing incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP)-mediated infections in Mengchao Hepatobiliary Hospital of Fujian Medical University in 2017 is the motivation behind this investigation to study gene phenotypes and resistance-associated genes of emergence regarding the CRKP strains. In current study, seven inpatients are enrolled in the hospital with complete treatments. The carbapenem-resistant K. pneumoniae whole genome is sequenced using MiSeq short-read and Oxford Nanopore long-read sequencing technology. Prophages are identified to assess genetic diversity within CRKP genomes. The investigation encompassed eight CRKP strains that collected from the patients enrolled as well as the environment, which illustrate that blaKPC-2 is responsible for phenotypic resistance in six CRKP strains that K. pneumoniae sequence type (ST11) is informed. The plasmid with IncR, ColRNAI and pMLST type with IncF[F33:A-:B-] co-exist in all ST11 with KPC-2-producing CRKP strains. Along with carbapenemases, all K. pneumoniae strains harbor two or three extended spectrum β-lactamase (ESBL)-producing genes. fosA gene is detected amongst all the CRKP strains. The single nucleotide polymorphisms (SNP) markers are indicated and validated among all CRKP strains, providing valuable clues for distinguishing carbapenem-resistant strains from conventional K. pneumoniae. In conclusion, ST11 is the main CRKP type, and blaKPC-2 is the dominant carbapenemase gene harbored by clinical CRKP isolates from current investigations.

scholarly journals Characterizing clinical carbapenem-resistant Klebsiella pneumoniae  phenotypes and genomic information reveals its molecular epidemiology

2019 ◽  
Author(s):  
Xiaoling Yu ◽  
Wen Zhang ◽  
Zhiping Zhao ◽  
Chengsong Ye ◽  
Shuyan Zhou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Pathogenic Bacteria ◽  
Efflux Pump ◽  
Carbapenem Resistance ◽  
Snp Markers ◽  
Nucleotide Polymorphisms ◽  
Phenotypic Resistance ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Long Read

Abstract The enhancing incidence of carbapenem-resistant Klebsiella pneumoniae (CRKP)-mediated infections in Mengchao Hepatobiliary Hospital of Fujian Medical University in 2017 promoted this investigation to study gene phenotypes and resistance genes of emergence regarding the CRKP strains. In current study, seven inpatients are enrolled in the hospital with complete treatments. The carbapenem-resistant K. pneumoniae whole genome is sequenced using MiSeq short-read and Oxford Nanopore long-read sequencing technology. Prophages are identified to assess genetic diversity within CRKP genomes. The investigation encompassed eight CRKP strains that collected from the patients enrolled as well as the environment, which illustrate that bla KPC-2 is responsible for phenotypic resistance in six CRKP strains that K . pneumoniae sequence type (ST-11) is inferred. The plasmid with IncR, ColRNAI and pMLST type with IncF[F33:A-:B-] co-exist in all ST-11 with KPC-2-producing CRKP strains. Along with carbapenemases, all K. pneumoniae strains harbor two or three extended spectrum β-lactamase (ESBL)-producing genes. F osA gene is detected amongst all the CRKP strains. The oqxA and oqxB expressions in CRKP strains may lead to carbapenem resistance since antimicrobials are expelled from pathogenic bacteria by efflux pump. The single nucleotide polymorphisms (SNP) markers are indicated and validated among all CRKP strains, providing valuable clues for distinguishing carbapenem-resistant strains from conventional K. pneumoniae .

scholarly journals Plasmidome analysis of carbapenem-resistant Enterobacteriaceae isolated in Vietnam

2020 ◽  
Author(s):  
Aki Hirabayashi ◽  
Koji Yahara ◽  
Satomi Mitsuhashi ◽  
So Nakagawa ◽  
Tadashi Imanishi ◽  
...  
Keyword(s):  
Carbapenem Resistance ◽  
Genomic Epidemiology ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Severe Infections ◽  
Oxford Nanopore Technologies ◽  
Carbapenem Resistant Enterobacteriaceae

Carbapenem-resistant Enterobacteriaceae (CRE) represent a serious threat to public health due to limited management of severe infections and high mortality. The rate of resistance of Enterobacteriaceae isolates to major antimicrobials, including carbapenems, is much higher in Vietnam than in Western countries, but the reasons remain unknown due to the lack of genomic epidemiology research. A previous study suggested that carbapenem resistance genes, such as the carbapenemase gene bla NDM-1 , spread via plasmids among Enterobacteriaceae in Vietnam. In this study, we performed detection and molecular characterization of bla NDM-1 -carrying plasmids in CRE isolated in Vietnam, and identified several possible cases of horizontal transfer of plasmids both within and among species of bacteria. Twenty-five carbapenem-resistant isolates from Enterobacteriaceae clinically isolated in a reference medical institution in Hanoi were sequenced on Illumina short-read sequencers, and 12 isolates harboring bla NDM-1 were sequenced on an Oxford Nanopore Technologies long-read sequencer to obtain complete plasmid sequences. Most of the plasmids co-carried genes conferring resistance to clinically relevant antimicrobials, including third-generation cephalosporins, aminoglycosides, and fluoroquinolones, in addition to bla NDM-1 , leading to multidrug resistance of their bacterial hosts. These results provide insight into the genetic basis of CRE in Vietnam, and could help control nosocomial infections.

scholarly journals 1202. Multimodal Sequencing of a Clonal Case Cluster of Carbapenem-Resistant Citrobacter Reveals Unexpectedly Rapid Dynamics of KPC3-Containing Plasmids

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S364-S364
Author(s):  
Roby Bhattacharyya ◽  
Alejandro Pironti ◽  
Bruce J Walker ◽  
Abigail Manson ◽  
Virginia Pierce ◽  
...  
Keyword(s):  
Point Mutations ◽  
Illumina Miseq ◽  
Nucleotide Polymorphisms ◽  
Sequencing Data ◽  
Single Nucleotide ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Close Relationship ◽  
Long Read ◽  
Carbapenem Resistant Enterobacteriaceae

Abstract Background Carbapenem-resistant Enterobacteriaceae (CRE) are a major public health threat. We report four clonally related Citrobacter freundii isolates harboring the blaKPC-3 carbapenemase in April–May 2017 that are nearly identical to a strain from 2014 at the same institution. Despite differing by ≤5 single nucleotide polymorphisms (SNPs), these isolates exhibited dramatic differences in carbapenemase plasmid architecture. Methods We sequenced four carbapenem-resistant C. freundii isolates from 2017 and compared them with an ongoing CRE surveillance project at our institution. SNPs were identified from Illumina MiSeq data aligned to a reference genome using the variant caller Pilon. Plasmids were assembled from Illumina and Oxford Nanopore sequencing data using Unicycler. Results The four 2017 isolates differed from one another by 0–5 chromosomal SNPs; two were identical. With one exception, these isolates differed by >38,000 SNPs from 25 C. freundii isolates sequenced from 2013 to 2017 at the same institution for CRE surveillance. The exception was a 2014 isolate that differed by 13–16 SNPs from each 2017 isolate, with 13 SNPs common to all four. Each C. freundii isolate harbored wild-type blaKPC-3. Despite the close relationship among the 2017 cluster, the plasmids harboring the blaKPC-3 genes differed dramatically: the carbapenemase occurred in one of the two different plasmids, with rearrangements between these plasmids across isolates. The related 2014 isolate harbored both plasmids, each with a separate copy of blaKPC-3. No transmission chains were found between any of the affected patients. Conclusion WGS confirmed clonality among four contemporaneous blaKPC-3-containing C. freundii isolates, and marked similarity with a 2014 isolate, within an institution. That only 13–16 SNPs varied between the 2014 and 2017 isolates suggests durable persistence of the blaKPC-3 gene within this lineage in a hospital ecosystem. The plasmids harboring these carbapenemase genes proved remarkably plastic, with plasmid loss and rearrangements occurring on the same time scale as two to three chromosomal point mutations. Combining short and long-read sequencing in a case cluster uniquely revealed unexpectedly rapid dynamics of carbapenemase plasmids, providing critical insight into their manner of spread. Disclosures M. J. Ferraro, SeLux Diagnostics: Scientific Advisor and Shareholder, Consulting fee. D. C. Hooper, SeLux Diagnostics: Scientific Advisor, Consulting fee.

scholarly journals A Cluster of Colistin- and Carbapenem-Resistant Klebsiella pneumoniae Carrying blaNDM-1 and mcr-8.2

2019 ◽  
Vol 221 (Supplement_2) ◽  
pp. S237-S242 ◽  
Author(s):  
Ke Ma ◽  
Yu Feng ◽  
Lu Liu ◽  
Zhihong Yao ◽  
Zhiyong Zong
Keyword(s):  
Klebsiella Pneumoniae ◽  
Nucleotide Polymorphisms ◽  
Illumina Hiseq ◽  
Carbapenem Resistant ◽  
Interhospital Transfer ◽  
Transmissible Plasmid ◽  
New Variant ◽  
Long Read ◽  
Illumina Hiseq Platform ◽  
Resistant Strains

Abstract Background Klebsiella pneumoniae resistant to both carbapenems and colistin imposes severe challenges for management. In this study, we report a cluster of 5 carbapenem-resistant K pneumoniae clinical strains belonging to ST1 and K57 types, 4 of which were also resistant to colistin, from 2 hospitals. Methods The 5 strains were subjected to whole-genome sequencing (WGS) using the short-read Illumina HiSeq platform, and 2 strains were also selected for long-read WGS using MinION. Clonal relatedness of the 5 strains was determined based on single-nucleotide polymorphisms (SNPs). Conjugation experiments were performed to obtain self-transmissible plasmids. Results All 5 strains carried the carbapenemase-encoding gene blaNDM-1, whereas the 4 colistin-resistant strains also harbored a new variant of the mcr-8 colistin resistance gene, namely, mcr-8.2. MCR-8.2 differs from MCR-8.1 by four amino acid substitutions (A51V, A232S, N365Y, and N480K). mcr-8.2 was located on a large, hybrid, nonself-transmissible plasmid containing IncQ, IncR, and IncFII replicons, whereas blaNDM-1 was carried by self-transmissible IncX3 plasmids. Phylogenetic analysis based on SNPs revealed that the 5 strains were likely to have a common origin. Conclusions Both the intra- and interhospital transfer of strains carrying mcr-8 and blaNDM-1 were identified, which represents an emerging threat for clinical management and infection control.

scholarly journals Plasmid analysis of NDM metallo-β-lactamase-producing Enterobacterales isolated in Vietnam

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0231119
Author(s):  
Aki Hirabayashi ◽  
Koji Yahara ◽  
Satomi Mitsuhashi ◽  
So Nakagawa ◽  
Tadashi Imanishi ◽  
...  
Keyword(s):  
Carbapenem Resistance ◽  
Hybrid Plasmid ◽  
Genomic Epidemiology ◽  
Carbapenem Resistant ◽  
Plasmid Analysis ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Third Generation Cephalosporins ◽  
Oxford Nanopore Technologies

Carbapenem-resistant Enterobacterales (CRE) represent a serious threat to public health due to the lack of treatment and high mortality. The rate of antimicrobial resistance of Enterobacterales isolates to major antimicrobials, including carbapenems, is much higher in Vietnam than in Western countries, but the reasons remain unknown due to the lack of genomic epidemiology research. A previous study suggested that carbapenem resistance genes, such as the carbapenemase gene blaNDM, spread via plasmids among Enterobacterales in Vietnam. In this study, we characterized blaNDM-carrying plasmids in Enterobacterales isolated in Vietnam, and identified several possible cases of horizontal transfer of plasmids both within and among species of bacteria. Twenty-five carbapenem-nonsusceptible isolates from a medical institution in Hanoi were sequenced on Illumina short-read sequencers, and 13 blaNDM-positive isolates, including isolates of Klebsiella pneumoniae, Escherichia coli, Citrobacter freundii, Morganella morganii, and Proteus mirabilis, were further sequenced on an Oxford Nanopore Technologies long-read sequencer to obtain complete plasmid sequences. Almost identical 73 kb IncFII(pSE11)::IncN hybrid plasmids carrying blaNDM-1 were found in a P. mirabilis isolate and an M. morganii isolate. A 112 kb IncFII(pRSB107)::IncN hybrid plasmid carrying blaNDM-1 in an E. coli isolate had partially identical sequences with a 39 kb IncR plasmid carrying blaNDM-1 and an 88 kb IncFII(pHN7A8)::IncN hybrid plasmid in a C. freundii isolate. 148–149 kb IncFIA(Hl1)::IncA/C2 plasmids and 75–76 kb IncFII(Yp) plasmids, both carrying blaNDM-1 were shared among three sequence type 11 (ST11) isolates and three ST395 isolates of K. pneumoniae, respectively. Most of the plasmids co-carried genes conferring resistance to clinically relevant antimicrobials, including third-generation cephalosporins, aminoglycosides, and fluoroquinolones, in addition to blaNDM-1. These results provide insight into the genetic basis of CRE in Vietnam, and could help control nosocomial infections.

scholarly journals Identification of AbaR4 Acinetobacter baumannii resistance island in clinical isolates of blaOXA-23-positive Proteus mirabilis

2019 ◽  
Vol 75 (3) ◽  
pp. 521-525 ◽  
Author(s):  
Sophie Octavia ◽  
Weizhen Xu ◽  
Oon Tek Ng ◽  
Kalisvar Marimuthu ◽  
Indumathi Venkatachalam ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Proteus Mirabilis ◽  
National Surveillance ◽  
Class D ◽  
Oxford Nanopore ◽  
Carbapenemase Gene ◽  
Long Read ◽  
Encoding Gene ◽  
Resistance Island

Abstract Objectives bla OXA-23 is a class D carbapenemase-encoding gene typical of the Acinetobacter genus. However, its occurrence in the Enterobacteriaceae is uncommon. Here we provide the genome characterization of blaOXA-23-positive Proteus mirabilis. Methods In Singapore, a national surveillance of carbapenem non-susceptible clinical Enterobacteriaceae has enabled the collection of OXA-23 bearing isolates. Three clinical P. mirabilis were whole-genome sequenced using Oxford Nanopore MinION and Illumina platforms. The sequence accuracy of MinION long-read contigs was enhanced by polishing with Illumina-derived short-read data. Results In two P. mirabilis genomes, blaOXA-23 was detected as two copies, present on the chromosome and on a 60018 bp plasmid. blaOXA-23 was associated with the classic Acinetobacter composite transposon Tn2006, bounded by two copies of ISAba1 bracketing the carbapenemase gene. The Tn2006 itself was embedded within an Acinetobacter baumannii AbaR4 resistance island. In the chromosome, the AbaR4 was found integrated into the comM gene, which is also the preferred ‘hotspot’ in A. baumannii. In the plasmid, AbaR4 integrated into a putative colicin gene. Conclusions Our description of an A. baumannii AbaR4 encoding blaOXA-23 in P. mirabilis is to our knowledge the first description of an Acinetobacter resistance island in Proteus and suggests that P. mirabilis may be a reservoir for this class D carbapenemase gene.

scholarly journals Successive Emergence of Ceftazidime-Avibactam Resistance through Distinct Genomic Adaptations in bla KPC-2 -Harboring Klebsiella pneumoniae Sequence Type 307 Isolates

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Marla J. Giddins ◽  
Nenad Macesic ◽  
Medini K. Annavajhala ◽  
Stephania Stump ◽  
Sabrina Khan ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Rapid Evolution ◽  
Carbapenem Resistance ◽  
Sequence Type ◽  
Content Type ◽  
Carbapenem Resistant ◽  
Oxford Nanopore ◽  
Long Read ◽  
Stepwise Evolution ◽  
Emergence Of Resistance

ABSTRACT Ceftazidime-avibactam (CAZ-AVI) is a promising novel treatment for infections caused by carbapenem-resistant Enterobacteriaceae (CRE). Despite improved treatment outcomes compared to those achieved with aminoglycoside- and colistin-based regimens, the rapid evolution of CAZ-AVI resistance during treatment has previously been reported in Klebsiella pneumoniae sequence type 258 (ST258) bla KPC-3 -harboring isolates. Here, we report the stepwise evolution and isolation of two phenotypically distinct CAZ-AVI-resistant Klebsiella pneumoniae isolates from a patient with pancreatitis. All susceptible ( n = 3) and resistant ( n = 5) isolates were of the ST307 clonal background, a rapidly emerging clone. Taking advantage of short-read Illumina and long-read Oxford Nanopore sequencing and full-length assembly of the core chromosome and plasmids, we demonstrate that CAZ-AVI resistance first occurred through a 532G → T bla KPC-2 point mutation in bla KPC-2 (D179Y protein substitution) following only 12 days of CAZ-AVI exposure. While subsequent isolates exhibited substantially decreased meropenem (MEM) MICs (≤2 μg/ml), later cultures demonstrated a second CAZ-AVI resistance phenotype with a lower CAZ-AVI MIC (12 μg/ml) but also MEM resistance (MIC > 128 μg/ml). These CAZ-AVI- and MEM-resistant isolates showed evidence of multiple genomic adaptations, mainly through insertions and deletions. This included amplification and transposition of wild-type bla KPC-2 into a novel plasmid, an IS 1 insertion upstream of ompK36 , and disruption of the rfb gene locus in these isolates. Our findings illustrate the potential of CAZ-AVI resistance to emerge in non- K. pneumoniae ST258 clonal backgrounds and alternative bla KPC variants. These results raise concerns about the strong selective pressures incurred by novel carbapenemase inhibitors, such as avibactam, on isolates previously considered invulnerable to CAZ-AVI resistance. There is an urgent need to further characterize non-KPC-mediated modes of carbapenem resistance and the intrinsic bacterial factors that facilitate the rapid emergence of resistance during treatment.

Sign in / Sign up

Export Citation Format

Share Document