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Klebsiella pneumoniae strains that produce Klebsiella pneumoniae Carbapenemase (KPC) variants displaying resistance to ceftazidime-avibactam (CZA) often remain susceptible to meropenem (MEM), suggesting a potential therapeutic use of this carbapenem antibiotic. However, in vitro studies indicate that these sorts of strains can mutate becoming MEM-resistant, raising concerns about the effectiveness of carbapenems as treatment option. We have studied mutation rates occurring from the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae belonging to ST11. Two-step fluctuation assays (FAs) were conducted. In brief, initial cultures of KPC-114-producing K. pneumoniae showing 1 µg/mL MEM MIC were spread on Mueller-Hinton agar plates containing 2-8 µg/mL MEM. A second step of FA, at 4-16 µg/mL MEM was performed from a mutant colony obtained at 2 µg/mL MEM. Mutation rates were calculated using maximum likelihood estimation. Parental and mutant strains were sequenced by Illumina NextSeq, and mutations were predicted by variant-calling analysis. At 8 µg/mL MEM, mutants derived from parental CZA-resistant (MIC ≥ 64 µg/mL)/MEM-susceptible (MIC = 1 µg/mL) KPC-114-positive K. pneumoniae exhibited an accumulative mutation rate of 3.05 × 10 -19 mutations/cell/generation, whereas at 16 µg/mL MEM an accumulative mutation rate of 1.33 × 10 -19 mutations/cell/generation resulted in the reversion of KPC-114 (S181_P182 deletion) to KPC-2. These findings highlight that the reversion of MEM-susceptible KPC-114 to MEM-resistant KPC-2, in CZA-resistant K. pneumoniae ST11 is related to low mutation rates suggesting a low risk of therapeutic failure. In vivo investigations are necessary to confirm the clinical potential of MEM against CZA-resistant KPC variants.IMPORTANCEThe emergence of ceftazidime-avibactam (CZA) resistance among carbapenem-resistant Klebsiella pneumoniae is a major concern due to the limited therapeutic options. Strikingly, KPC mutations mediating CZA resistance are generally associated with meropenem susceptibility, suggesting a potential therapeutic use of this carbapenem antibiotic. However, the reversion of meropenem-susceptible to meropenem-resistant could be expected. Therefore, knowing the mutation rate related to this genetic event is essential to estimate the potential use of meropenem against CZA-resistant KPC-producing K. pneumoniae . In this study, we demonstrate, in vitro , that under high concentrations of meropenem, reversion of KPC-114 to KPC-2 in CZA-resistant/meropenem-susceptible K. pneumoniae belonging to the global high-risk ST11 is related to low mutation rates., Competing Interests: The authors declare no conflict of interest.

Reports of Gram-negative bacteria harboring multiple carbapenemase genes have increased in South America, leading to an urgent need for appropriate microbiological diagnosis. We evaluated phenotypic methods for detecting Klebsiella pneumoniae carbapenemase 2 (KPC-2) and New Delhi metallo-β-lactamase-1 (NDM-1) coexpression in members of the K. pneumoniae complex (i.e., K. pneumoniae, K. quasipneumoniae, and K. variicola) isolated from human and animal hosts, based on inhibition of ceftazidime-avibactam (CZA) and aztreonam (ATM) by dipicolinic acid (DPA), EDTA, or avibactam (AVI). While the presence of bla KPC-2 and bla NDM-1 genes was confirmed by whole-genome sequencing, PCR, and/or GeneXpert, coexpression was successfully detected based on the following: (i) a ≥5-mm increase in the zone diameter of ATM (30 µg) disks plus AVI (4 or 20 µg) and ≥4-mm and ≥10-mm increases in the zone diameters for "CZA 50" (30 µg ceftazidime [CAZ] and 20 µg AVI) and "CZA 14" (10 µg CAZ and 4 µg AVI) disks, respectively, when we added DPA (1 mg/disk) or EDTA (5 mM) in a combined disk test (CDT); (ii) a positive ghost zone (synergism) between ATM (30 µg) and CZA 50 disks and between CZA 50 and DPA (1 mg) disks, using the double-disk synergy test (DDST) at a disk-disk distance of 2.5 cm; (iii) ≥3-fold MIC reductions of ATM and CZA in the presence of AVI (4 µg/mL), DPA (500 µg/mL), or EDTA (320 µg/mL); and (iv) immunochromatography. Although our results demonstrated that inhibition by AVI, DPA, and EDTA may provide simple and inexpensive methods for the presumptive detection of coexpression of KPC-2 and NDM-1 in members of the K. pneumoniae complex, additional studies are necessary to confirm the accuracy of these methodologies by testing other Gram-negative bacterial species and other KPC and NDM variants coexpressed by WHO critical priority pathogens detected worldwide. IMPORTANCE Alerts regarding the emergence and increase of combinations of carbapenemases in Enterobacterales in Latin America and the Caribbean have recently been issued by PAHO and WHO, emphasizing the importance of appropriate microbiological diagnosis and the effective and articulated implementation of infection prevention and control programs. In this study, we evaluated methods based on inhibition of ceftazidime (CAZ), ceftazidime-avibactam (CZA), and aztreonam (ATM) by dipicolinic acid (DPA), EDTA, and avibactam (AVI) inhibitors for the identification of KPC-2- and NDM-1-coexpression in members of the K. pneumoniae complex recovered from human and animal hosts. Our results demonstrate that inhibition by AVI, DPA, and EDTA may provide simple and inexpensive methods for the presumptive detection of coexpression of KPC-2 and NDM-1 in members of the K. pneumoniae complex.

An unusual biotype of KPC-2-producing Klebsiella pneumoniae (KPC-Kpn) isolates was detected in Corrientes, Argentina, which, to their isolation date, had been free of KPC-Kpn outbreaks. Our aim was to describe the clinical epidemiology focused on genomic characterization of atypical urease-negative KPC-Kpn clinical isolates belonging to the high-risk hospital-associated clonal lineage ST340/CC258. Thirteen isolates were recovered, all of them from inpatients with KPC-Kpn infection (August 2015 to January 2016). These isolates displayed identical enterobacterial repetitive intergenic consensus-PCR electropherotype belonging to a single clonal sequence type ST340. Whole genome sequencing was performed on two KPC-Kpn and the resistome analyses revealed the following acquired resistance genes: bla KPC-2 , bla CTX-M-15, bla OXA-1, bla SHV-11, aac(3)-IId , aph(3')-Ia , aac(6')-Ib-cr, sul1 , dfrA14, catB3, fosA , and arr-3. Mutations in GyrA (S83I) and ParC (S80I) were also identified. Among the virulence determinants, yersiniabactin was detected in both strains, specifically the ybt9 locus located in ICE Kp3 . Five plasmid incompatibility groups were observed in this clone and an unusual IncP6 plasmid bearing bla KPC-2 gene (named pKpn3KP) was fully characterized. In this study, we present the first draft genome sequences of two clinical isolates of KPC-2/CTX-M-15-producing K. pneumoniae belonging to the high-risk clonal lineage ST340/CC258 associated with nosocomial outbreaks in Argentina.

Klebsiella pneumoniae is an opportunistic pathogen that can cause several infections, mainly in hospitalised or immunocompromised individuals. The spread of K. pneumoniae emerging virulent and multidrug-resistant clones is a worldwide concern and its identification is crucial to control these strains especially in hospitals. This article reports data related to multi-resistant K. pneumoniae strains, isolated from inpatients in the city of Manaus, Brazil, harbouring virulence and antimicrobial-resistance genes, including high-risk international clones belonging to clonal group (CG) 258. Twenty-one strains isolated from different patients admitted to four hospitals in the city of Manaus, located in the state of Amazonas, Northern Brazil (Amazon Rainforest region) were evaluated. The majority of strains (61.9% n = 13) were classified as multidrug-resistant (MDR), and five strains (23.8%) as extensively drug-resistant (XDR). Several virulence and antimicrobial-resistance genes were found among the strains and eight strains (38.1%) presented the hyper-mucoviscous phenotype. MLST analysis demonstrated a great diversity of STs among the strains, totaling 12 different STs (ST11, ST23, ST198, ST277, ST307, ST340, ST378, ST462, ST502, ST3991, ST3993 and ST5209). Three of these (ST11, ST23 and ST340) belong to CG258., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Convergence of resistance and virulence in Klebsiella pneumoniae is a critical public health issue worldwide. A multidrug-resistant CTX-M-15-producing K. pneumoniae (TIES-4900 strain) was isolated from a highly impacted urban river, in Brazil. The genome was sequenced by MiSeq Illumina platform and de novo assembled using Unicycler. In silico prediction was accomplished by bioinformatics tools. The size of the genome is 5.4 Mb with 5145 protein-coding genes. TIES-4900 strain belonged to the sequence type ST15, yersiniabactin sequence type YbST10, ICEKp4, KL24 (wzi-24) and O1v1 locus. Phylogenomics confirmed genomic relatedness with ST15 clones from human and animal hosts. Convergence of broad resistome (antibiotics, heavy-metals and biocides) and virulome, including the Kpi pilus system involved in host-pathogen interaction and persistence of ST15 clone to hospital environments, were predicted. Virulent behavior was confirmed in the Galleria mellonella infection model. This study may give genomic insights on the spread of critical-priority WHO pathogens beyond hospital settings., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

The emergence and rapid spread of carbapenemase-producing Enterobacterales represents a serious public health concern. Critically, these global priority bacteria have begun to be reported in companion animals, implying a potential risk of cross-transmission between humans and pets. Using long-read (MinION) and short-read (Illumina) sequencing technologies, we have identified and characterized a hypermucoviscous KPC-2-producing Klebsiella pneumoniae strain belonging to the high-risk international clone ST11/CG258, in a dog with urinary tract infection. Strikingly, the bla KPC-2 gene was carried by a 54-kb IncN plasmid assignated to ST15, which shared 99.8 and 96.8% pairwise identity with IncN-pST15 plasmids from human and environmental K. pneumoniae strains, respectively; all come from an area with high endemicity of KPC-2. Our findings suggest that IncN-pST15 plasmids conferring carbapenem resistance can play as important a role as clonal transmission of K. pneumoniae, representing another major challenge for One Health., (© 2021 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

Emergent hypervirulent Klebsiella pneumoniae has been responsible for severe diseases, representing a serious threat to public health. We report the whole-genome sequencing of a novel ST3994-K2 clone, a single locus variant of ST86 K2, which is considered a worrying hypervirulent clone that emerged in several parts of the world. The strain K. pneumonia Kpi144 was isolated in 2013 from a blood culture of a 69-year-old male patient admitted to a tertiary hospital in Teresina, state of Piauí, northeastern Brazil. The strain was susceptible to 41 antibiotics tested, presented hypermucoviscous phenotype and a virulent behavior was observed in the Galleria mellonella infection model. Moreover, the virulome showed several virulence genes. To the best of our knowledge, this is the first worldwide report of a novel ST3994-K2 K. pneumoniae clone, an SLV of ST86 K2, which is considered a worrying virulent clone that has emerged in several parts of the world, including South America and Brazil., (© The Author(s) 2021. Published by Oxford University Press on behalf of FEMS. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Resumo: The Klebsiella pneumoniae (K. pneumoniae) bacterium is responsible for many opportunistic infections such as sepsis, and a multidrug-resistant (MDR) clone sequence type (ST) 307 has recently begun to spread. The objective of this study was to report the first occurrence of this virulent genotype, which was found in the context of a urinary infection in a domestic feline in Brazil. The K. pneumoniae isolate was identified from the urine of a 6-month-old male crossbreed cat using 16S rRNA sequencing. It was then subjected to antimicrobial susceptibility testing, followed by multilocus sequence typing analysis, and PCR detection of virulence and resistance genes. The antimicrobial susceptibility profile demonstrated that the isolate was MDR and associated with the presence of the colistin resistance gene (mcr-1). Genotyping allowed us to classify the isolate as K. pneumoniae ST307 with the presence of wabG, uge, and entB genes. MDR K. pneumoniae is important in human and veterinary medicine because it causes many types of infections. Clonal propagation of virulent or MDR genotypes such as K. pneumoniae ST307 is a global concern. This report of ST307 isolation from a urine sample in a domestic feline is the first in Brazil.

Background: Extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae have been increasingly reported worldwide as a frequent cause of human and animal infections. K. pneumoniae belonging to the K24 capsular serotype and sequence type (ST) ST15 has been considered a global successful clone responsible for the spread of the bla CTX-M-15 gene., Objective: To report the draft genome sequence of a multidrug-resistant CTX-M-15-positive K. pneumoniae K24-ST15 strain (L3KP1), which was isolated from a dog with chronic otitis., Methods: Genomic DNA was extracted and sequenced using Illumina NextSeq platform. De novo assembly was performed by SPAdes and in silico prediction accomplished by curated bioinformatics tools., Results: The genome size was calculated at 5 642 348 bp, with a GC content of 57.11%, and comprising 5601 total genes, 52 tRNAs, 8 rRNAs, 9 ncRNAs and 105 pseudogenes. The K. pneumoniae L3KP1 strain belonged to ST15 and carried the yersiniabactin biosynthetic gene cluster [ybt 10 (YbST28) in the integrative conjugative element ICEKp4], and the KL24 locus encoding capsular serotype K24. Besides the bla CTX-M-15 ESBL gene, other clinically important resistance genes to β-lactams, aminoglycosides, fosfomycin, macrolides, phenicol, quinolones, sulfonamides, tetracyclines and trimethoprim were detected. Additionally, heavy metals and disinfectant resistance genes were also identified., Conclusion: This draft genome might be useful for comparative genomic analyses of the international clone of K. pneumoniae K24-ST15-CTX-M-15. In addition, information presented in this study also shed light on the urgent need to monitor ESBL-producing K. pneumoniae in veterinary hospitals., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Introduction: Infections caused by hypervirulent and/or hypermucoviscous Klebsiella pneumoniae (K. pneumoniae) strains are frequently reported worldwide. Since convergence of hypervirulence and drug-resistance emerged as a serious clinical problem, novel therapeutic strategies are worthy of investigation. In this regard, antimicrobial photodynamic therapy and blue light have proven to be effective against a broad-spectrum of clinically relevant pathogens but have never been tested for hypervirulent/hypermucoviscous strains. Thus, this study investigated the influence of hypermucoviscosity and hypervirulence over the photoinactivation efficacy of blue light alone or antimicrobial photodynamic therapy mediated by methylene blue and red light., Methods: Five clinical isolates of K. pneumoniae were screened for hypermucoviscosity by string test and for hypervirulence by a Galleria mellonella model of systemic infection. Strains were then challenged by both photoinactivation methods performed in vitro. All tests also included a non-hypervirulent/hypermucoviscous control strain for comparison., Results: All K. pneumoniae strains were effectively inactivated by both light-based antimicrobial strategies. Hypervirulent/hypermucoviscous strains exposed to photodynamic therapy presented rapid and consistent inactivation kinetics, while blue light led to slower and more variable inactivation kinetics., Conclusion: Hypermucoviscosity and hypervirulence does not confer tolerance in K. pneumoniae against photoinactivation. Antimicrobial photodynamic therapy represents an interesting alternative to treat localised infections because it is a fast procedure with high effectiveness. On the other hand, antimicrobial blue light could be used to decontaminate hospital environments since no photosensitiser administration is required and harmful effects of ultraviolet light are avoided. Therefore, visible light-based strategies present great potential for the development of safe and effective antimicrobial technologies against such aggressive pathogens., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This study used whole-genome sequencing (WGS) and PFGE to analysis KPC-2-producing Klebsiella pneumoniae strains from clinical specimens collected in Brazilian hospitals. The study identifies the emergence of a novel small IncX3 plasmid (pKPB11), 12,757-bp in length, in a high-risk K. pneumoniae ST11/CG258 lineage, a successful clonal group in Brazil, carrying the bla KPC-2 gene on a non-Tn4401 genetic element (NTE KPC -Ic). Comparative analysis of the pKPB11 showed that this plasmid reduced its size, losing part of its conjugation apparatus. The pKPB11 was also compared to another strain sequenced in this study (KPC89) that had the hybrid IncX3-IncU plasmid (pKP89), of approximately 45 kb in length, similarly carrying the bla KPC-2 gene on NTE KPC -Ic. To the best of our knowledge, pKPB11 is the first example of small IncX3 plasmid found in a high-risk KPC-2-producing K. pneumoniae ST11/CG258., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Objectives: Klebsiella pneumoniae sequence type 307 (ST307) has emerged as a new high-risk clone worldwide. The aim of this study was to report the draft genome sequence of a multidrug-resistant CTX-M-15-positive K. pneumoniae strain causing urinary tract infection in a companion animal in Brazil., Methods: Whole-genome sequencing was performed on an Illumina NextSeq platform and the genome was de novo assembled using SPAdes. Data analysis was performed using online tools from the Center for Genomic Epidemiology., Results: The genome size of K. pneumoniae strain PRETA was calculated at 5 450 575 bp, containing a total of 5355 protein-coding sequences. The strain was assigned to the high-risk ST307 and carried the clinically relevant bla CTX-M-15 gene, besides other genes conferring resistance to aminoglycosides, tetracyclines, quinolones, trimethoprim and fosfomycin., Conclusion: These data offer novel information for comparative genomic analyses in order to track the transmission dynamics and epidemiology of the newly emerging high-risk clone ST307., (Copyright © 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.)

Objectives: KPC-producing Klebsiella pneumoniae is considered one of the most worrisome multidrug-resistant micro-organisms in nosocomial infections. It has also been reported in wastewater and urban rivers in the city of Sao Paulo, Brazil. Here we report the draft genome sequences of three KPC-2- and CTX-M-15-producing K. pneumoniae sequence type 437 (ST437) isolates obtained from two urban rivers and from a clinical sample of a patient in Sao Paulo., Methods: A genomic library was constructed using a Nextera XT Kit. An Illumina platform was used to perform whole-genome sequencing (WGS)., Results: WGS of environmental isolates Kp148/PINH-4900 and Kp196/TIET-4200 and clinical isolate Kp314/11 resulted in estimated genome sizes of 5464058, 5437723 and 5319218bp, respectively. Resistome analysis of the environmental and clinical strains revealed the presence of resistance genes to the following antimicrobials in all strains: aminoglycosides [aac(6')-Ib-cr]; β-lactams (bla OXA-1 , bla SHV-11 , bla CTX-M-15 and bla KPC-2 ); fluoroquinolones [aac(6')-Ib-cr, oqxA and oqxB]; fosfomycin (fosA KP ); macrolides [mph(A)]; phenicols (catB4); sulfonamides (sul1); and trimethoprim (dfrA30). The tetracycline resistance gene tetA was identified in Kp148/PINH-4900 and Kp314/11 only; the aminoglycoside resistance gene aph(3')-Ia was found only in environmental isolates, and aadA2 only in Kp314/11; and the phenicol resistance gene catA1 was identified only in Kp148/PINH-4900., Conclusions: The draft genome sequences of these strains help us to elucidate the dissemination of resistance genes in micro-organisms inside and outside the hospital and are useful for further comparisons between clinical and environmental strains., (Copyright © 2018 International Society for Chemotherapy of Infection and Cancer. Published by Elsevier Ltd. All rights reserved.)

Extended spectrum β-lactamase (ESBL)-producing bacterial infections in veterinary medicine are a clinical and epidemiological challenge. We report a case of CTX-M-15-producing Klebsiella pneumoniae infection followed by persistent colonization, in a dog presenting with bilateral purulent nasal discharge and dyspnea. In this regard, 5 broad-spectrum cephalosporin-resistant K. pneumoniae isolates were recovered from infection and surveillance cultures, collected during 1 year and eight months study. Genomic analysis of a representative clone of K. pneumoniae (KpPB76) revealed the presence of the human-associated lineage ST231, whereas resistome data confirmed the presence of genes conferring resistance to aminoglycosides, β-lactams, fluoroquinolones, fosfomycin, phenicols, sulfonamides, tetracyclines and trimethoprim. In the absence of therapeutic options, meropenem therapy was used, contributing to the control of infection during persistent carriage of K. pneumoniae CTX-M-15/ST231. Persistent colonization of companion animals with ESBL-producing bacteria could be result from a variety of situations, including multi introduction from the owner or household family members to pets, or from environmental exposure; whereas colonized animals may serve as an important source for the spread of ESBL-producing strains in the human-animal interface., (Copyright © 2018 Elsevier Inc. All rights reserved.)

In this study, we describe the frequency of virulence genes in Klebsiella pneumoniae carbapenemase-2-producing Klebsiella pneumoniae (KPC-KP), including hypervirulent (hv) and hypermucoviscous (hm) strains by whole-genome sequencing. We also evaluate the capacity for biofilm formation by using phenotypic techniques. The occurrence of several virulence genes (fimABCDEFGHIK, mrkABCDFHJ, ecpA, wabG, entB, ugE, irp1, irp2, traT, iutA and ureADE) and a high frequency of hvhmKPC-KP isolates was found. Most hospital-associated lineages of KPC-KP belong to the international clonal group 258 (CG258). Biofilm formation was a constant feature among 90.9 % of KPC-KP strains. This report suggests a close relationship between ST437 and weak biofilm production, given that all weakly biofilm-producing strains belonged to this sequence type. This also supports the dissemination of KPC-KP containing numerous virulence determinants belonging to the biofilm-producing CG258 type in Brazil, including hv and hm strains. These factors allow this pathogen to cause infections, leading to its rapid expansion and persistence in hospital settings.

The emergence of hypervirulent Klebsiella pneumoniae (hvKP) with multidrug resistance (MDR) profile is a worrisome public health issue. We report the first draft genome sequence of a hypermucoviscous (positive string test) and MDR K. pneumoniae serotype K19, belonging to ST29, isolated from human infection. This strain harboured multiple antimicrobial resistance genes, including blaCTX-M-15, besides yersiniabactin and type 3 fimbriae virulence genes. In vivo experiments carried out with the Galleria mellonella infection model revealed that K. pneumoniae K19/ST29 killed 100% of the larvae at 24 h post-infection, in a similar way to the known hypermucoviscous hvKP K1/ST23 lineage., (© FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The horizontal transfer of a plasmid bearing the bla KPC-2 gene from K. pneumoniae to E. cloacae infecting the respiratory tract of a patient during meropenem therapy was elucidated. This finding is particularly worrisome, since these drugs are of last resort for multidrug-resistant Gram-negative pathogens., (Copyright © 2017 Elsevier Inc. All rights reserved.)

This report describes an outbreak of suppurative peritonitis caused by Klebsiella pneumoniae in an adult female of captive golden-handed tamarin (Saguinus midas midas). Two virulent and multidrug-resistant strains were isolated and classified through MLST as ST60 and ST1263. The microbiological diagnosis works as a support tool for preventive measures., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

The aim of this study was to investigate the presence and prevalence of bla(TEM), bla(SHV), and bla(CTX-M) and bla(GES)-like genes, responsible for extended spectrum beta-lactamases (ESBLs) production in clinical isolates of Klebsiella pneumoniae collected from a Brazilian tertiary care hospital. Sixty-five ESBL producing K. pneumoniae isolates, collected between 2005 and 2007, were screened by polymerase chain reaction (PCR). Identification of bla genes was achieved by sequencing. Genotyping of ESBL producing K. pneumoniae was performed by the enterobacterial repetitive intergenic consensus-PCR with cluster analysis by the Dice coefficient. The presence of genes encoding ESBLs was confirmed in 59/65 (90.8%) isolates, comprising 20 bla(CTX-M-2), 14 bla(CTX-M-59), 12 bla(CTX-M-15), 9 bla(SHV-12), 1 bla(SHV-2), 1 bla(SHV-2a), 1 bla(SHV-5), and 1 bla(SHV-31) genes. The ESBL genes bla(SHV-12), bla(SHV-31), and bla(CTX-M-15), and the chromosome-encoded SHV-type beta-lactamase capable of hydrolyzing imipenem were detected in Brazil for the first time. The analysis of the enterobacterial repetitive intergenic consensus-PCR band patterns revealed a high rate of multiclonal bla(CTX-M) carrying K. pneumoniae isolates (70.8%), suggesting that dissemination of encoding plasmids is likely to be the major cause of the high prevalence of these genes among the K. pneumoniae isolates considered in this study., (© Mary Ann Liebert, Inc.)

A multiresistant Klebsiella pneumoniae isolate was taken from the blood of a 75-year-old patient with nosocomial pneumonia who developed septic shock and failed therapy with imipenem. The isolate presented an MIC of imipenem of 128 microg/ml, and the production of a metallo-beta-lactamase was confirmed by phenotypic and genotypic techniques. We here report, for the first time, the detection of a metalloenzyme (IMP-1)-producing K. pneumoniae clinical strain in Latin America. The gene responsible for this phenotype was found to be bla(IMP-1), carried in a class 1 integron.

Klebsiella variicola is mainly associated with opportunistic infections and frequently identified as Klebsiella pneumoniae. This misidentification implies a wrong epidemiology result as well as incorrect attribution to K. pneumoniae as the etiology of some severe infections. Recently, huge efforts have been made to study K. variicola , however, the biological aspects of this species are still unclear. Here we characterized five K. variicola strains initially identified as K. pneumoniae , with a Vitek-2 System and 16S rRNA sequencing. One-step multiplex polymerase chain reaction and Whole Genome Sequencing (WGS) identified them as K. variicola. Additionally, WGS analysis showed that all the strains are closely related with K. variicola genomes, forming a clustered group, apart from K. pneumoniae and K. quasipneumoniae. Multilocus sequence typing analysis showed four different sequence types (STs) among the strains and for two of them (Kv97 and Kv104) the same ST was assigned. All strains were multidrug-resistant (MDR) and three showed virulence phenotypes including invasion capacity to epithelial cells, and survival in human blood and serum. These results showed the emergence of new K. variicola clones with pathogenic potential to colonize and cause infection in different tissues. These characteristics associated with MDR strains raise great concern for human health. [ABSTRACT FROM AUTHOR]

An unusual biotype of KPC-2-producing Klebsiella pneumoniae (KPC-Kpn) isolates was detected in Corrientes, Argentina, which, to their isolation date, had been free of KPC-Kpn outbreaks. Our aim was to describe the clinical epidemiology focused on genomic characterization of atypical urease-negative KPC-Kpn clinical isolates belonging to the high-risk hospital-associated clonal lineage ST340/CC258. Thirteen isolates were recovered, all of them from inpatients with KPC-Kpn infection (August 2015 to January 2016). These isolates displayed identical enterobacterial repetitive intergenic consensus-PCR electropherotype belonging to a single clonal sequence type ST340. Whole genome sequencing was performed on two KPC-Kpn and the resistome analyses revealed the following acquired resistance genes: blaKPC-2, blaCTX-M-15,blaOXA-1,blaSHV-11,aac(3)-IId, aph(3′)-Ia, aac(6′)-Ib-cr, sul1, dfrA14, catB3, fosA, and arr-3. Mutations in GyrA (S83I) and ParC (S80I) were also identified. Among the virulence determinants, yersiniabactin was detected in both strains, specifically the ybt9 locus located in ICEKp3. Five plasmid incompatibility groups were observed in this clone and an unusual IncP6 plasmid bearing blaKPC-2 gene (named pKpn3KP) was fully characterized. In this study, we present the first draft genome sequences of two clinical isolates of KPC-2/CTX-M-15-producing K. pneumoniae belonging to the high-risk clonal lineage ST340/CC258 associated with nosocomial outbreaks in Argentina. [ABSTRACT FROM AUTHOR]

The rapid increased multidrug resistance in Klebsiella pneumoniae has led to a renewed interest in polymyxin antibiotics, such as colistin, as antibiotics of last resort, not least in low/middle income countries. We conducted a genomic survey of clinical polymyxin-resistant K. pneumoniae to investigate the genetic alterations in isolates harboring blaKPC-2. Whole-genome sequencing was performed using an Illumina NextSeq 500 paired-end reads. Mutations and insertion sequence detection were analyzed to seven isolates recovered from clinical specimens of patients hospitalized in Brazil, focusing on key genes associated with polymyxin resistance. Furthermore, the levels of mRNA expression of genes associated with resistance to polymyxin B and other antimicrobials were evaluated by quantitative real-time PCR. Eighty-five percent of the isolates were assigned to clonal complex 258, with a minimum inhibitory concentration range of 4 to >256 mg/L for polymyxin B. It was possible to observe the presence of one important insertion element, ISKpn13, in a strain recovered from the blood that have blaKPC-2. Deleterious mutations reported in PmrB (R256G), YciM (N212T), and AcrB (T598A) were common, and mobile colistin resistance (mcr) genes were absent in all the isolates. RT-qPCR analysis revealed an overexpression of the pmrC (1.160-fold), pmrD (2.258-fold), and kpnE (1.530-fold) genes in the polymyxin B-resistant isolates compared with the expression of the polymyxin B-susceptible K. pneumoniae isolate. Overall, these results demonstrate the diversity of genetic variations in polymyxin-resistant populations derived from the different clonal strains, but the same sequence types, and suggest that there are still unknown mechanisms of polymyxin resistance in K. pneumoniae. [ABSTRACT FROM AUTHOR]

A multidrug-resistant CTX-M-15-producing Klebsiella pneumoniae (KpP1 strain) was isolated from a native Amazonian fish (Brachyplatystoma filamentosum) at the Brazilian Amazon. The strain was identified by MALDI-TOF. The genome was extracted, purified and a Nextera DNA Flex library was prepared and sequenced by Illumina platform. The sequenced genome was de novo assembled using Unicycler and in silico prediction accomplished by curated bioinformatics tools. The size of the genome is 5.6 Mb with 5715 genes. Whole-genome sequencing analysis revealed the presence of wide resistome, with genes conferring resistance to clinically relevant antibiotics, heavy metals and disinfectants. The KpP1 strain was assigned to the sequence type ST3827, KL111 (wzi 113) and O3b locus. Native freshwater fish sold in wet markets of the Amazonian region could be an important vehicle for transmission of multidrug-resistant bacteria to humans. This study may give genomic insights on the spread of critical-priority WHO pathogens in a One Health context. • A multidrug-resistant Klebsiella pneumoniae was isolated from a native Amazonian fish. • Genomic analysis revealed that K. pneumoniae belonged to ST3827, KL111 and O3b locus. • A wide resistome against heavy metals, disinfectants, and relevant antibiotics was predicted. • ESBL production was associated with the bla CTX-M-15 gene carried on an IncFII(K) plasmid. • Native freshwater fishes could be a vehicle for transmission of critical-priority pathogens. [ABSTRACT FROM AUTHOR]

The emergence and dissemination of high-risk clones of Klebsiella pneumoniae producing extended-spectrum β-lactamases (ESBLs) in animal infections is a critical issue. We report the detection and genomic features of a multidrug-resistant (MDR) ESBL (CTX-M-15)-producing K. pneumoniae infecting a domestic cat. Whole-genome sequencing analysis identified the international ST340 (clonal group CG258), and genes and mutations conferring resistance to β-lactams, aminoglycosides, macrolides, phenicols, fosfomycin, sulfonamides, tetracycline, trimethoprim, and fluoroquinolones. In addition, the presence of genes encoding resistance to disinfectant and heavy metals hazardous to humans was also confirmed. The MDR profile exhibited by the strain contributed to treatment failure and death of the companion animal. Therefore, active surveillance of critical priority lineages of K. pneumoniae should not only focus on human infections but also on veterinary infections. [ABSTRACT FROM AUTHOR]

The first two are involved in toxin and antitoxin (TA) systems, and I rop1 i gene in the regulation of replication of the plasmid, while maintaining the I aphA(3')-Vla i , I bla i SB TEM sb , and I bla i SB KPC-2 sb genes (Fig. Interestingly, the literature has described the importance of small plasmids (~10 kb) as an adaptation phenomenon both in terms of physical conditioning costs and antibiotic resistance levels, which will determine the success of the persistence of these small plasmid carrier clones during and after antibiotic treatment.[10] Small-plasmid-mediated antibiotic resistance is enhanced by increases in plasmid copy number and bacterial fitness. [Extracted from the article]