Expansion of ESBL-producing Klebsiella pneumoniae in hospitalized patients: a successful story of international clones (ST15, ST147, ST336) and epidemic plasmids (IncR, IncFIIK)

Whole genome sequencing reveals complex resistome features of Klebsiella pneumoniae isolated from patients at major hospitals in Trinidad, West Indies

OBJECTIVES

Antibiotic-resistant Klebsiella pneumoniae is a human pathogen of major global concern due to its ability to cause multiple severe diseases that are often difficult to treat therapeutically. This study aimed to investigate the resistome of local clinical K. pneumoniae isolates.

METHODS

Herein, we used a whole genome sequencing approach and bioinformatics tools to reconstruct the resistome of 10 clinical K. pneumoniae isolates and one clinical isolate of the closely related Klebsiella quasipneumoniae obtained from patients from three major hospitals in Trinidad, West Indies.

RESULTS

The results of the study revealed the presence of a complex antibiotic-resistant armoury among the local isolates with multiple resistance mechanisms involving (i) inactivation of antibiotics, (ii) efflux pumps, (iii) antibiotic target alteration, protection, and replacement against antibiotics, and (iv) altered porin protein that reduced the permeability to antibiotics. Several resistance genes such as blaCTX-M-15, blaTEM-1B, blaSHV-28, blaKPC-2, oqxA, sul1, tetD, aac(6')-Ib-cr5, aph(6)-Id, and fosA6, which are known to confer resistance to antibiotics used to treat K. pneumoniae infections. In most cases, the resistance genes were flanked by mobile elements, including insertion sequences and transposons, which facilitate the spread of these genetic features among related organisms.

CONCLUSION

This is the first comprehensive study to thoroughly investigate the resistome of clinical K. pneumoniae isolates and K. quasipneumoniae from Trinidad, West Indies. These findings suggest that monitoring K. pneumoniae and its genome-wide antibiotic resistance features in clinical strains would be of critical importance for guiding antibiotic stewardship programs and improving regional disease management systems for this pathogen.

Occurrence and characteristics of extended-spectrum-β-lactamase- and pAmpC-producing Klebsiella pneumoniae isolated from companion animals with urinary tract infections

This study examined 70 Klebsiella pneumoniae isolates derived from companion animals with urinary tract infections in Taiwan. Overall, 81% (57/70) of the isolates carried extended-spectrum β-lactamase (ESBL) and/or plasmid-encoded AmpC (pAmpC) genes. ESBL genes were detected in 19 samples, with blaCTX-M-1, blaCTX-M-9, and blaSHV being the predominant groups. pAmpC genes were detected in 56 isolates, with blaCIT and blaDHA being the predominant groups. Multilocus sequence typing revealed that sequence types (ST)11, ST15, and ST655 were prevalent. wabG, uge, entB, mrkD, and fimH were identified as primary virulence genes. Two isolates demonstrated a hypermucoviscosity phenotype in the string test. Antimicrobial susceptibility testing exhibited high resistance to β-lactams and fluoroquinolones in ESBL-positive isolates but low resistance to aminoglycosides, sulfonamides, and carbapenems. Isolates carrying pAmpC genes exhibited resistance to penicillin-class β-lactams. These findings provide valuable insights into the role of K. pneumoniae in the context of the concept of One Health.

Interhospital Spread of blaVIM-1- and blaCTX-M-15-Producing K. pneumoniae ST15 on an IncR Plasmid in Southern Spain

In 2014-2015, the main CTX-M-15- and OXA-48-producing clone in our region was ST15. Recently, K. pneumoniae ST15 isolates co-producing VIM-1 and CTX-M-15 were detected in several hospitals. The aim was to study the emergence and acquisition of this carbapenemase. Between 2017 and 2019, four hospitals submitted twenty-nine VIM-1- and CTX-M-15-producing K. pneumoniae ST15 isolates to our laboratory. Seven representatives of each XbaI PFGE pulsotype were sequenced using short- and long-read technologies. RAST, CGE databases, and Pathogenwatch were used for resistance determinants and capsule-type analysis. Plasmid comparison was performed with Easyfig2.1. Phylogenetic analysis included other contemporary ST15 isolates from Spain. The 29 isolates were clustered into seven different pulsotypes. The selected genomes, from three hospitals in two different provinces, were clustered together (fewer than 35 alleles) and differed by more than 100 alleles from other ST15 isolates obtained in the region. These seven isolates harbored one IncR plasmid (200-220 kb) with a common backbone and four regions flanked by IS26: one contained blaVIM-1, another contained blaCTX-M-15, the third contained blaOXA-1, and the fourth harbored heavy-metal-tolerance genes. The two initial plasmids, from two different centers, were identical, and rearrangement of four regions was observed in the five subsequent plasmids. Our findings showed the first intercenter dissemination of IncR plasmids carrying blaVIM-1, blaCTX-M-15, and metal-tolerance genes mediated by a new lineage of K. pneumoniae ST15. Two different capture events of the blaVIM-1 gene or different IS26-mediated plasmid rearrangements from a common ancestor may explain plasmid variations.

From Farm to Fork: Persistence of Clinically Relevant Multidrug-Resistant and Copper-Tolerant Klebsiella pneumoniae Long after Colistin Withdrawal in Poultry Production

Concerns about colistin-resistant bacteria in animal food-environmental-human ecosystems prompted the poultry sector to implement colistin restrictions and explore alternative trace metals/copper feed supplementation. The impact of these strategies on the selection and persistence of colistin-resistant Klebsiella pneumoniae in the whole poultry production chain needs clarification. We assessed colistin-resistant and copper-tolerant K. pneumoniae occurrence in chickens raised with inorganic and organic copper formulas from 1-day-old chicks to meat (7 farms from 2019 to 2020), after long-term colistin withdrawal (>2 years). Clonal diversity and K. pneumoniae adaptive features were characterized by cultural, molecular, and whole-genome-sequencing (WGS) approaches. Most chicken flocks (75%) carried K. pneumoniae at early and preslaughter stages, with a significant decrease (P < 0.05) in meat batches (17%) and sporadic water/feed contamination. High rates (>50%) of colistin-resistant/mcr-negative K. pneumoniae were observed among fecal samples, independently of feed. Most samples carried multidrug-resistant (90%) and copper-tolerant (81%; silA and pcoD positive and with a MICCuSO4 of ≥16 mM) isolates. WGS revealed accumulation of colistin resistance-associated mutations and F type multireplicon plasmids carrying antibiotic resistance and metal/copper tolerance genes. The K. pneumoniae population was polyclonal, with various lineages dispersed throughout poultry production. ST15-KL19, ST15-KL146, and ST392-KL27 and IncF plasmids were similar to those from global human clinical isolates, suggesting chicken production as a reservoir/source of clinically relevant K. pneumoniae lineages and genes with potential risk to humans through food and/or environmental exposure. Despite the limited mcr spread due to the long-term colistin ban, this action was ineffective in controlling colistin-resistant/mcr-negative K. pneumoniae, regardless of feed. This study provides crucial insights into the persistence of clinically relevant K. pneumoniae in the poultry production chain and highlights the need for continued surveillance and proactive food safety actions within a One Health perspective. IMPORTANCE The spread of bacteria resistant to last-resort antibiotics such as colistin throughout the food chain is a serious concern for public health. The poultry sector has responded by restricting colistin use and exploring alternative trace metals/copper feed supplements. However, it is unclear how and to which extent these changes impact the selection and persistence of clinically relevant Klebsiella pneumoniae throughout the poultry chain. We found a high occurrence of copper-tolerant and colistin-resistant/mcr-negative K. pneumoniae in chicken flocks, regardless of inorganic and organic copper formulas use and a long-term colistin ban. Despite the high K. pneumoniae isolate diversity, the occurrence of identical lineages and plasmids across samples and/or clinical isolates suggests poultry as a potential source of human K. pneumoniae exposure. This study highlights the need for continued surveillance and proactive farm-to-fork actions to mitigate the risks to public health, relevant for stakeholders involved in the food industry and policymakers tasked with regulating food safety.

Whole-Genome Sequencing and Comparative Genomics Analysis of a Newly Emerged Multidrug-Resistant Klebsiella pneumoniae Isolate of ST967

Klebsiella pneumoniae is a common cause of hospital- and community-acquired infections globally, yet its population structure remains unknown for many regions, particularly in low- and middle-income countries (LMICs). Here, we report for the first-time whole-genome sequencing (WGS) of a multidrug-resistant K. pneumoniae isolate, ARM01, recovered from a patient in Armenia. Antibiotic susceptibility testing revealed that ARM01 was resistant to ampicillin, amoxicillin-clavulanic acid, ceftazidime, cefepime, norfloxacin, levofloxacin, and chloramphenicol. Genome sequencing analysis revealed that ARM01 belonged to sequence type 967 (ST967), capsule type K18, and antigen type O1. ARM01 carried 13 antimicrobial resistance (AMR) genes, including blaSHV-27, dfrA12, tet(A), sul1, sul2, catII.2, mphA, qnrS1, aadA2, aph3-Ia, strA, and strB and the extended-spectrum β-lactamase (ESBL) gene blaCTX-M-15, but only one known virulence factor gene, yagZ/ecpA, and one plasmid replicon, IncFIB(K)(pCAV1099-114), were detected. The plasmid profile, AMR genes, virulence factors, accessory gene profile, and evolutionary analyses of ARM01 showed high similarity to isolates recovered from Qatar (SRR11267909 and SRR11267906). The date of the most recent common ancestor (MRCA) of ARM01 was estimated to be around 2017 (95% confidence interval [CI], 2017 to 2018). Although in this study, we report the comparative genomics analysis of only one isolate, it emphasizes the importance of genomic surveillance for emerging pathogens, urging the need for implementation of more effective infection prevention and control practices. IMPORTANCE Whole-genome sequencing and population genetics analysis of K. pneumoniae are scarce from LMICs, and none has been reported for Armenia. Multilevel comparative analysis revealed that ARM01 (an isolate belonging to a newly emerged K. pneumoniae ST967 lineage) was genetically similar to two isolates recovered from Qatar. ARM01 was resistant to a wide range of antibiotics, reflecting the unregulated usage of antibiotics (in most LMICs, antibiotic use is typically unregulated.) Understanding the genetic makeup of these newly emerging lineages will aid in optimizing antibiotic use for patient treatment and contribute to the worldwide efforts of pathogen and AMR surveillance and implementation of more effective infection prevention and control strategies.

Phylogenomics of Globally Spread Clonal Groups 14 and 15 of Klebsiella pneumoniae

Klebsiella pneumoniae sequence type 14 (ST14) and ST15 caused outbreaks of CTX-M-15 and/or carbapenemase producers worldwide, but their phylogeny and global dynamics remain unclear. We clarified the evolution of K. pneumoniae clonal group 14 (CG14) and CG15 by analyzing the capsular locus (KL), resistome, virulome, and plasmidome of public genomes (n = 481) and de novo sequences (n = 9) representing main sublineages circulating in Portugal. CG14 and CG15 evolved independently within 6 main subclades defined according to the KL and the accessory genome. The CG14 (n = 65) clade was structured in two large monophyletic subclades, CG14-I (KL2, 86%) and CG14-II (KL16, 14%), whose emergences were dated to 1932 and 1911, respectively. Genes encoding extended-spectrum β-lactamase (ESBL), AmpC, and/or carbapenemases were mostly observed in CG14-I (71% versus 22%). CG15 clade (n = 170) was segregated into subclades CG15-IA (KL19/KL106, 9%), CG15-IB (variable KL types, 6%), CG15-IIA (KL24, 43%) and CG15-IIB (KL112, 37%). Most CG15 genomes carried specific GyrA and ParC mutations and emerged from a common ancestor in 1989. CTX-M-15 was especially prevalent in CG15 (68% CG15 versus 38% CG14) and in CG15-IIB (92%). Plasmidome analysis revealed 27 predominant plasmid groups (PG), including particularly pervasive and recombinant F-type (n = 10), Col (n = 10), and new plasmid types. While blaCTX-M-15 was acquired multiple times by a high diversity of F-type mosaic plasmids, other antibiotic resistance genes (ARGs) were dispersed by IncL (blaOXA-48) or IncC (blaCMY/TEM-24) plasmids. We first demonstrate an independent evolutionary trajectory for CG15 and CG14 and how the acquisition of specific KL, quinolone-resistance determining region (QRDR) mutations (CG15), and ARGs in highly recombinant plasmids could have shaped the expansion and diversification of particular subclades (CG14-I and CG15-IIA/IIB). IMPORTANCE Klebsiella pneumoniae represents a major threat in the burden of antibiotic resistance (ABR). Available studies to explain the origin, the diversity, and the evolution of certain ABR K. pneumoniae populations have mainly been focused on a few clonal groups (CGs) using phylogenetic analysis of the core genome, the accessory genome being overlooked. Here, we provide unique insights into the phylogenetic evolution of CG14 and CG15, two poorly characterized CGs which have contributed to the global dissemination of genes responsible for resistance to first-line antibiotics such as β-lactams. Our results point out an independent evolution of these two CGs and highlight the existence of different subclades structured by the capsular type and the accessory genome. Moreover, the contribution of a turbulent flux of plasmids (especially multireplicon F type and Col) and adaptive traits (antibiotic resistance and metal tolerance genes) to the pangenome reflect the exposure and adaptation of K. pneumoniae under different selective pressures.

Occurrence of Multidrug-Resistant Bacteria Resulting from the Selective Pressure of Antibiotics: A Comprehensive Analysis of ESBL K. pneumoniae and MRSP Isolated in a Dog with Rhinorrhea

Because of public health concerns, much greater scrutiny is now placed on antibiotic use in pets, especially for antimicrobial agents that have human analogs. Therefore, this study aimed to characterize the phenotypic and genotypic profiles of multidrug-resistant bacteria isolated from nasal swabs samples taken from a one-year-old male Serra da Estrela dog with rhinorrhea that was treated with amikacin. An extended-spectrum β-lactamases (ESBL) Klebsiella pneumoniae was isolated in the first sample taken from the left nasal cavity of the dog. Seven days later, methicillin-resistant (MRSP) Staphylococcus pseudintermedius was also isolated. Nevertheless, no alterations to the therapeutic protocol were performed. Once the inhibitory action of the antibiotic disappeared, the competitive advantage of the amikacin-resistant MRSP was lost, and only commensal flora was observed on both nasal cavities. The genotypic profile of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae revealed the same characteristics and close relation to other strains, mainly from Estonia, Slovakia and Romania. Regarding MRSP isolates, although resistance to aminoglycosides was present in the first MRSP, the second isolate carried aac(6')-aph(2″), which enhanced its resistance to amikacin. However, the veterinary action was focused on the treatment of the primary agent (ESBL K. pneumoniae), and the antibiotic applied was according to its phenotypic profile, which may have led to the resolution of the infectious process. Therefore, this study highlights the importance of targeted therapy, proper clinical practice and laboratory-hospital communication to safeguard animal, human and environmental health.

Unravelling the Evolutionary Dynamics of High-Risk Klebsiella pneumoniae ST147 Clones: Insights from Comparative Pangenome Analysis

BACKGROUND

The high prevalence and rapid emergence of antibiotic resistance in high-risk Klebsiella pneumoniae (KP) ST147 clones is a global health concern and warrants molecular surveillance.

METHODS

A pangenome analysis was performed using publicly available ST147 complete genomes. The characteristics and evolutionary relationships among ST147 members were investigated through a Bayesian phylogenetic analysis.

RESULTS

The large number of accessory genes in the pangenome indicates genome plasticity and openness. Seventy-two antibiotic resistance genes were found to be linked with antibiotic inactivation, efflux, and target alteration. The exclusive detection of the bla_OXA-232 gene within the ColKp3 plasmid of KP_SDL79 suggests its acquisition through horizontal gene transfer. The association of seventy-six virulence genes with the acrAB efflux pump, T6SS system and type I secretion system describes its pathogenicity. The presence of Tn6170, a putative Tn7-like transposon in KP_SDL79 with an insertion at the flanking region of the tnsB gene, establishes its transmission ability. The Bayesian phylogenetic analysis estimates ST147's initial divergence in 1951 and the most recent common ancestor for the entire KP population in 1621.

CONCLUSIONS

Present study highlights the genetic diversity and evolutionary dynamics of high-risk clones of K. pneumoniae. Further inter-clonal diversity studies will help us understand its outbreak more precisely and pave the way for therapeutic interventions.

Exploring the Antibiotic Resistance Profile of Clinical Klebsiella pneumoniae Isolates in Portugal

While antibiotic resistance is rising to dangerously high levels, resistance mechanisms are spreading globally among diverse bacterial species. The emergence of antibiotic-resistant Klebsiella pneumoniae, mainly due to the production of antibiotic-inactivating enzymes, is currently responsible for most treatment failures, threatening the effectiveness of classes of antibiotics used for decades. This study assessed the presence of genetic determinants of β-lactam resistance in 102 multi-drug resistant (MDR) K. pneumoniae isolates from patients admitted to two central hospitals in northern Portugal from 2010 to 2020. Antimicrobial susceptibility testing revealed a high rate (>90%) of resistance to most β-lactam antibiotics, except for carbapenems and cephamycins, which showed antimicrobial susceptibility rates in the range of 23.5−34.3% and 40.2−68.6%, respectively. A diverse pool of β-lactam resistance genetic determinants, including carbapenemases- (i.e., blaKPC-like and blaOXA-48-like), extended-spectrum β-lactamases (ESBL; i.e., blaTEM-like, blaCTX-M-like and blaSHV-like), and AmpC β-lactamases-coding genes (i.e., blaCMY-2-like and blaDHA-like) were found in most K. pneumoniae isolates. blaKPC-like (72.5%) and ESBL genes (37.3−74.5%) were the most detected, with approximately 80% of K. pneumoniae isolates presenting two or more resistance genes. As the optimal treatment of β-lactamase-producing K. pneumoniae infections remains problematic, the high co-occurrence of multiple β-lactam resistance genes must be seen as a serious warning of the problem of antimicrobial resistance.

Plasmidome in mcr-1 harboring carbapenem-resistant enterobacterales isolates from human in Thailand

The emergence of the mobile colistin-resistance genes mcr-1 has attracted significant attention worldwide. This study aimed to investigate the genetic features of mcr-1-carrying plasmid among carbapenem-resistant Enterobacterales (CRE) isolates and the potential genetic basis governing transmission. Seventeen mcr-harboring isolates were analyzed based on whole genome sequencing using short-read and long-read platforms. All the mcr-1-carrying isolates could be conjugatively transferred into a recipient Escherichia coli UB1637. Among these 17 isolates, mcr-1 was located on diverse plasmid Inc types, consisting of IncX4 (11/17; 64.7%), IncI2 (4/17; 23.53%), and IncHI/IncN (2/17; 11.76%). Each of these exhibited remarkable similarity in the backbone set that is responsible for plasmid replication, maintenance, and transfer, with differences being in the upstream and downstream regions containing mcr-1. The IncHI/IncN type also carried other resistance genes (bla_TEM-1B or bla_TEM-135). The mcr-1-harboring IncX4 plasmids were carried in E. coli ST410 (7/11; 63.6%) and ST10 (1/11; 9.1%) and Klebsiella pneumoniae ST15 (1/11; 9.1%), ST336 (1/11; 9.1%), and ST340 (1/11; 9.1%). The IncI2-type plasmid was harbored in E. coli ST3052 (1/4; 25%) and ST1287 (1/4; 25%) and in K. pneumoniae ST336 (2/4; 50%), whereas IncHI/IncN were carried in E. coli ST6721 (1/2; 50%) and new ST (1/2; 50%). The diverse promiscuous plasmids may facilitate the spread of mcr-1 among commensal E. coli or K. pneumoniae strains in patients. These results can provide information for a surveillance system and infection control for dynamic tracing.

Protective effect of two new nanovaccines against Pseudomonas aeruginosa based on LPS and OPS: A comparison study

Pseudomonas aeruginosa is one of the most important infectious pathogens in medicine. This bacterium causes various infections, especially in patients with severe burns and people with defective immune systems. The purpose of this study was to develop a nanovaccine based on PLGA nanoparticles and lipopolysaccharide and oligopolysaccharide antigens for appropriate stimulation of the humoral and cellular immune systems against P. aeruginosa. LPS-PLGA and OPS-PLGA conjugates were synthesized using the carbodiimide reaction. The prepared conjugates of as well as the pure antigens of LPS and OPS were injected to BALB/c mice in three periods at 2 week intervals. The ELISA test showed that the IgM, IgA, IgG, IgG1, IgG2b, IgG2a and IgG3 antibodies produced against LPS-PLGA or OPS-PLGA conjugates were tens of times higher than the pure antigens. Also, the opsonophagocytosis test showed that the performance and the effect of produced anti-LPS-PLGA antibodies were higher than other groups. In addition, the mice treated with LPS-PLGA conjugate were more resistant to P. aeruginosa infection than other groups. These findings indicated that LPS and OPS antigens in conjugation with PLGA nanoparticles have the ability to create and effective immunity against P. aeruginosa and LPS-PLGA is more effective than OPS-PLGA.

Occurrence of Healthcare-Associated Infections (HAIs) by Escherichia coli and Klebsiella spp. Producing Extended-Spectrum β-lactamases (ESBL) and/or Carbapenemases in Portuguese Long-Term Care Facilities

Extended-spectrum-β-lactamase (ESBL)- and carbapenemase-producing bacteria are widespread in hospitals, but the extent of this problem in long-term care facilities (LTCFs) is poorly understood. We aimed to elucidate, in the Portuguese regional clinical context, the relevance of LTCFs as a reservoir of Escherichia coli and Klebsiella spp. producing ESBL- and/or carbapenemases (Ec/Kp-ESBL/CARB). Fourteen LTCFs from Portugal, corresponding to units of convalescence (UC/n = 3), medium-term internment and rehabilitation (UMDR/ n = 5), or long-term internment and maintenance (ULDM/n = 6), were analyzed (2016–2019). All patients with Ec/Kp-ESBL/CARB infections acquired during LTCF stay were included, and detailed information was collected. Prevalence of patients with healthcare-associated infections (HAIs) by Ec/Kp-ESBL/CARB did not vary significantly over time (1.48% in 2016–2017, 1.89% in 2017–2018, and 1.90% in 2018–2019), but a statistically significant association with the LTCF typology (ULDM, UMDR) was observed. HAIs were caused by K. pneumoniae (n = 51/54.3%), E. coli (n = 41/43.6%), or both (n = 2/2.1%), producing ESBL (96%) or carbapenemases (4%). Prior colonization (n = 14/16%) corresponded to seven Kp-CARB and seven Ec/Kp-ESBL. The worrying prevalence of patients acquiring HAIs by Ec/Kp-ESBL/CARB, associated with the estimated rates of those already colonized at admission, highlights a relevant role for LTCFs as a reservoir of Ec/Kp-ESBL/CARB. Epidemiological surveillance should be extended to the national level, and colonization screening at LTCF admission implemented systematically.

Changes in Fecal Carriage of Extended-Spectrum β-Lactamase Producing Enterobacterales in Dutch Veal Calves by Clonal Spread of Klebsiella pneumoniae

This study aimed to characterize the changes in fecal carriage of Extended-Spectrum β-Lactamase (ESBL) producing Enterobacterales (ESBL-PE) in a single Dutch veal calves. During the rearing period at the Dutch veal farm, a decrease in fecal carriage of cefotaxime-resistant Escherichia coli isolates was observed after 2 weeks at the veal farm, while an increase of cefotaxime-resistant Klebsiella pneumoniae isolates was demonstrated. E. coli and K. pneumoniae were isolated from rectal swabs collected from 110 veal calves in week 2, 6, 10, 18, and 24 after their arrival at the farm. ESBL-PE isolates were selectively cultured and identified by MALDI-TOF. ESBL genes were characterized by RT-PCR, PCRs, and amplicon sequencing. A total of 80 E. coli and 174 K. pneumoniae strains were isolated from 104 out of 110 veal calves. The prevalence of ESBL-E. coli decreased from week 2 (61%) to week 6 (7%), while an unexpected increase in ESBL-K. pneumoniae colonization was detected in week 6 (80%). The predominant ESBL genes detected in E. coli isolates were bla_CTX-M-15 and the non-ESBL gene bla_TEM-1a, while in K. pneumoniae bla_CTX-M-14 gene was detected in all isolates. Four cefotaxime-resistant K. pneumoniae isolates were randomly selected and characterized in deep by transformation, PCR-based replicon typing, and whole-genome sequencing (WGS). The clonal relatedness of a subgroup of nine animals carrying K. pneumoniae ESBL genes was investigated by Multi Locus sequence typing (MLST). In four ESBL-K. pneumoniae isolates, bla_CTX-M-14 was located on IncFII_K and IncFII_NK plasmid replicons and the isolates were multi-drug resistant (MDR). MLST demonstrated a clonal spread of ESBL-K. pneumoniae ST107. To the best of our knowledge, this is the first study to report a change in fecal carriage of ESBL-PE over time in the same veal calf during the rearing period.

Whole genome sequencing of Klebsiella pneumoniae clinical isolates sequence type 627 isolated from Egyptian patients

Klebsiella pneumoniae is considered a threat to public health especially due to multidrug resistance emergence. It is largely oligoclonal based on multi-locus sequence typing (MLST); in Egypt, ST 627 was recently detected. Despites the global dissemination of this ST, there is still paucity of information about it. Herein, we used 4 K. pneumoniae ST627 for whole genome sequencing utilizing an Illumina MiSeq platform. Genome sequences were examined for resistance and virulence determinants, capsular types, plasmids, insertion sequences, phage regions, and Clustered Regularly Interspaced Palindromic Repeats (CRISPR) regions using bioinformatic analysis. The molecular characterization revealed 15 and 65 antimicrobial resistance and virulence genes, respectively. Resistance genes such as tet(D), aph(3’’)-Ib, aph(6)-Id, blaTEM-234, fosA, and fosA6; were mainly responsible for tetracycline, aminoglycoside, and fosfomycin resistance; respectively. The capsular typing revealed that the four strains are KL-24 and O1v1. One plasmid was found in all samples known as pC17KP0052-1 and another plasmid with accession no. NZ_CP032191.1 was found only in K90. IncFIB(K) and IncFII(K) are two replicons found in all samples, while ColRNAI replicon was found only in K90. Entero P88, Salmon SEN5, and Klebsi phiKO2 intact phage regions were identified. All samples harbored CRISPR arrays including CRISPR1 and CRISPR2. Our results shed light on critical tasks of mobile genetic elements in ST 627 in antibiotic resistance spreading.

Molecular Epidemiology of Extended-Spectrum Beta-Lactamase and AmpC Producing Enterobacteriaceae among Sepsis Patients in Ethiopia: A Prospective Multicenter Study

Extended-spectrum beta-lactamases (ESBLs) and AmpC producing Enterobacteriaceae are public health threats. This study aims to characterize ESBL and AmpC producing Enterobacteriaceae isolated from sepsis patients. A multicenter study was conducted at four hospitals located in central (Tikur Anbessa and Yekatit 12), southern (Hawassa) and northern (Dessie) parts of Ethiopia. Blood culture was performed among 1416 sepsis patients. Enterobacteriaceae (n = 301) were confirmed using MALDI-TOF and subjected for whole genome sequencing using the Illumina (HiSeq 2500) system. The overall genotypic frequencies of ESBL and AmpC producing Enterobacteriaceae were 75.5% and 14%, respectively. The detection of ESBL producing Enterobacteriaceae at Hawassa, Yekatit 12, Tikur Anbessa and Dessie was 95%, 90%, 82% and 55.8%, respectively. The detection frequency of bla_CTX-M, bla_TEM and bla_SHV genes was 73%, 63% and 33%, respectively. The most frequently detected ESBL gene was bla_CTX-M-15 (70.4%). The common AmpC genes were bla_ACT (n = 22) and bla_CMY (n = 13). Of Enterobacteriaceae that harbored AmpC (n = 42), 71% were ESBL co-producers. Both bla_TEM-1B (61.5%) and bla_SHV-187 (27.6%) were the most frequently detected variants of bla_TEM and bla_SHV, respectively. The molecular epidemiology of ESBL producing Enterobacteriaceae showed high frequencies and several variants of ESBL and AmpC genes. Good antimicrobial stewardship and standard bacteriological laboratory services are necessary for the effective treatment of ESBL producing Enterobacteriaceae.

Genomic evolution of the globally disseminated multidrug-resistant Klebsiella pneumoniae clonal group 147

The rapid emergence of multidrug-resistant Klebsiella pneumoniae is being driven largely by the spread of specific clonal groups (CGs). Of these, CG147 includes 7-gene multilocus sequence typing (MLST) sequence types (STs) ST147, ST273 and ST392. CG147 has caused nosocomial outbreaks across the world, but its global population dynamics remain unknown. Here, we report a pandrug-resistant ST147 clinical isolate from India (strain DJ) and define the evolution and global emergence of CG147. Antimicrobial-susceptibility testing following European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines and genome sequencing (Illumina and Oxford Nanopore Technologies, Unicycler assembly) were performed on strain DJ. Additionally, we collated 217 publicly available CG147 genomes [National Center for Biotechnology Information (NCBI), May 2019]. CG147 evolution was inferred within a temporal phylogenetic framework (beast) based on a recombination-free sequence alignment (Roary/Gubbins). Comparative genomic analyses focused on resistance and virulence genes and other genetic elements (BIGSdb, Kleborate, PlasmidFinder, phaster, ICEfinder and CRISPRCasFinder). Strain DJ had a pandrug-resistance phenotype. Its genome comprised the chromosome, seven plasmids and one linear phage-plasmid. Four carbapenemase genes were detected: bla_NDM-5 and two copies of bla_OXA-181 in the chromosome, and a second copy of bla_NDM-5 on an 84 kb IncFII plasmid. CG147 genomes carried a mean of 13 acquired resistance genes or mutations; 63 % carried a carbapenemase gene and 83 % harboured bla_CTX-M. All CG147 genomes presented GyrA and ParC mutations and a common subtype I-E CRISPR-Cas system. ST392 and ST273 emerged in 2005 and 1995, respectively. ST147, the most represented phylogenetic branch, was itself divided into two main clades with distinct capsular loci: KL64 (74 %, DJ included, emerged in 1994 and disseminated worldwide, with carbapenemases varying among world regions) and KL10 (20 %, emerged in 2002, predominantly found in Asian countries, associated with carbapenemases NDM and OXA-48-like). Furthermore, subclades within ST147-KL64 differed at the yersiniabactin locus, OmpK35/K36 mutations, plasmid replicons and prophages. The absence of IncF plasmids in some subclades was associated with a possible activity of a CRISPR-Cas system. K. pneumoniae CG147 comprises pandrug-resistant or extensively resistant isolates, and carries multiple and diverse resistance genes and mobile genetic elements, including chromosomal bla_NDM-5. Its emergence is being driven by the spread of several phylogenetic clades marked by their own genomic features and specific temporo–spatial dynamics. These findings highlight the need for precision surveillance strategies to limit the spread of particularly concerning CG147 subsets.

NDM-1 Introduction in Portugal through a ST11 KL105 Klebsiella pneumoniae Widespread in Europe

The changing epidemiology of carbapenem-resistant Klebsiella pneumoniae in Southern European countries is challenging for infection control, and it is critical to identify and track new genetic entities (genes, carbapenemases, clones) quickly and with high precision. We aimed to characterize the strain responsible for the first recognized outbreak by an NDM-1-producing K. pneumoniae in Portugal, and to elucidate its diffusion in an international context. NDM-1-producing multidrug-resistant K. pneumoniae isolates from hospitalized patients (2018–2019) were characterized using FTIR spectroscopy, molecular typing, whole-genome sequencing, and comparative genomics with available K. pneumoniae ST11 KL105 genomes. FT-IR spectroscopy allowed the rapid (ca. 4 h after incubation) identification of the outbreak strains as ST11 KL105, supporting outbreak control. Epidemiological information supports a community source but without linkage to endemic regions of NDM-1 producers. Whole-genome comparison with previous DHA-1-producing ST11 KL105 strains revealed the presence of different plasmid types and antibiotic resistance traits, suggesting the entry of a new strain. In fact, this ST11 KL105 clade has successfully disseminated in Europe with variable beta-lactamases, but essentially as ESBL or DHA-1 producers. We expand the distribution map of NDM-1-producing K. pneumoniae in Europe, at the expense of a successfully established ST11 KL105 K. pneumoniae clade circulating with variable plasmid backgrounds and beta-lactamases. Our work further supports the use of FT-IR as an asset to support quick infection control.

Studies on molecular epidemiology of ESβL-producing Klebsiella pneumoniae isolated from patients hospitalized in a specialist hospital in southern Poland

Introduction. Extended-spectrum β-lactamase (ESβL)-producing Klebsiella pneumoniae is currently one of the most common causes of nosocomial infections worldwide. The study aimed to characterize antibiotic resistance profile, the prevalence of selected genes encoding ESβLs, virulence, and the genetic relationship in 139 K. pneumoniae isolates identified in John Paul II Specialist Hospital in Southern Poland, collected in 2016.

Materials/Methods. Bacterial identification and the preliminary antibiotic susceptibilities was performed using the VI-TEK® 2 Compact automated system. Genes encoding ESβLs were amplified by CTX-Mplex PCR and PCR reactions. The presence of nine genes encoding virulence factors was studied by multiplex PCR. Clonality was investigated by PFGE after digestion with SpeI endonuclease.

Results. K. pneumoniae were mostly recovered from the respiratory tract (40.3%), urine (32.4%), wound swabs (19.4%) and blood (5%). In summary, 82.7% of strains were classified as multidrug resistant (MDR). All isolates were confirmed as ESβL producers and carried bla CTX-M-type (85.6%), bla SHV (82%), bla TEM (77.7%), bla CTX-M-9 (75.6%) and bla CTX-M-1 (1.4%) in various combinations. Moreover, triple bla genes were observed in 72% of isolates. The most common virulence-as-sociated genes found among the isolates were entB (91.4%), ybtS (55.4%), iutA (55.4%), magA (53.2%), kfu (14.4%), K2 (11.5%), mrkD (10.1%), rmpA (7.9%) and allS (5%). The PFGE analysis identified 4 major clusters (A–D) comprising 61% of the entire collection.

Conclusions. Our results indicate that the presence of a wide variety of MDR K. pneumoniae harbor ESβLs and virulence genes. Studies on molecular epidemiology of ESβL-producing K. pneumoniae isolates are needed, particularly for epidemiological surveillance in the hospital environment.

Bacteriocins: Properties and potential use as antimicrobials

A variety of bacteriocins originate from lactic acid bacteria, which have recently been modified by scientists. Many strains of lactic acid bacteria related to food groups could produce bacteriocins or antibacterial proteins highly effective against foodborne pathogens such as Staphylococcus aureus, Pseudomonas fluorescens, P. aeruginosa, Salmonella typhi, Shigella flexneri, Listeria monocytogenes, Escherichia coli O157:H7, and Clostridium botulinum. A wide range of bacteria belonging primarily to the genera Bifidobacterium and Lactobacillus have been characterized with different health‐promoting attributes. Extensive studies and in‐depth understanding of these antimicrobials mechanisms of action could enable scientists to determine their production in specific probiotic lactic acid bacteria, as they are potentially crucial for the final preservation of functional foods or for medicinal applications. In this review study, the structure, classification, mode of operation, safety, and antibacterial properties of bacteriocins as well as their effect on foodborne pathogens and antibiotic‐resistant bacteria were extensively studied.

Co-transfer of plasmid-encoded bla carbapenemases genes and mercury resistance operon in high-risk clones of Klebsiella pneumoniae

Carbapenemase-producing Klebsiella pneumoniae (CP-Kp) is a real global health threat. Environmental reservoirs of resistance gene determinats, such as effluents of hospital wastewaters, are acquiring increased relevance in the selection of plasmid-encoded carbapenemase genes. The presence of Hg in environmental reservoirs may exert a positive selective pressure on tolerant bacteria, favoring the co-transfer of carbapenemase genes and mer operons. In our study, 63 CP-Kp isolates were screened for mer operons by whole genome sequencing (MySeq). Conjugation assays were performed with 24 out of 63 CP-Kp isolates harboring the mer operon. Ten transconjugants (Tc-Kp) were selected with Hg. Plasmid DNA of Tc-Kp was extracted and sequenced using single-molecule real-time (SMRT) technology (PacBio, Sequel II system) with later annotation. Plasmid analysis revealed that Tc-Kp from bla_IMP-like (n = 3) showed a single plasmid belonging to IncC group with two complete mer operon next to bla_IMP-like. Tc-Kp from bla_VIM-1 (n = 2) harbored two plasmids, one with bla_VIM-1 in an IncL, and mer operon was in an IncFIB plasmid. Tc-Kp from bla_OXA-48-like (n = 5) showed 2 plasmids. bla_OXA-48-like was found in an IncL plasmid, whereas mer operon was (i) in an IncR plasmid associated with bla_CTX-M-15 in 3 Tc-Kp-OXA-48-like, (ii) in an IncC plasmid associated with bla_CMY-2 in 1 Tc-Kp-OXA-48-like, (iii) and in an IncFIB plasmid associated with bla_CTX-M-15 in 1 Tc-Kp-OXA-48-like. This is, to our knowledge, the first study to describe in K. pneumoniae producing plasmid-encoded carbapenemase, the potential impact of Hg in the co-transfer of mer operons and carbapenemase genes located in the same or different plasmids. KEY POINTS: • Environmental reservoirs are playing an important role in the selection of carbapenemase genes. • Conjugation assays, selecting with Hg, obtained 10 transconjugants with carbapenemase genes. • mer operons were located in the same or different plasmids than carbapenemase genes.

Characterization of ESBL-Producing Escherichia coli and Klebsiella pneumoniae Isolated from Clinical Samples in a Northern Portuguese Hospital: Predominance of CTX-M-15 and High Genetic Diversity

Background: Enterobacteriaceae are major players in the spread of resistance to β-lactam antibiotics through the action of CTX-M β-lactamases. We aimed to analyze the diversity and genetic characteristics of ESBL-producing Escherichia coli and Klebsiella pneumoniae isolates from patients in a Northern Portuguese hospital. Methods: A total of 62 cefotaxime/ceftazidime-resistant E. coli (n = 38) and K. pneumoniae (n = 24) clinical isolates were studied. Identification was performed by MALDI-TOF MS. Antimicrobial susceptibility testing against 13 antibiotics was performed. Detection of ESBL-encoding genes and other resistance genes, phylogenetic grouping, and molecular typing (for selected isolates) was carried out by PCR/sequencing. Results: ESBL activity was detected in all 62 E. coli and K. pneumoniae isolates. Most of the ESBL-producing E. coli isolates carried a bla_CTX-M gene (37/38 isolates), being bla_CTX-M-15 predominant (n = 32), although bla_CTX-M-27 (n = 1) and bla_CTX-M-1 (n = 1) were also detected. Two E. coli isolates carried the bla_KPC2/3 gene. The lineages ST131-B2 and ST410-A were detected among the ESBL-producing blood E. coli isolates. Regarding the 24 ESBL-producing K. pneumoniae isolates, 18 carried a bla_CTX-M gene (bla_CTX-M-15, 16 isolates; bla_CTX-M-55, 2 isolates). All K. pneumoniae isolates carried bla_SHV genes, including ESBL-variants (bla_SHV-12 and bla_SHV-27, 14 isolates) or non-ESBL-variants (bla_SHV-11 and bla_SHV-28, 10 isolates); ten K. pneumoniae isolates also carried the bla_KPC2/3 gene and showed imipenem-resistance. ESBL-positive E. coli isolates were ascribed to the B₂ phylogenetic group (82%), mostly associated with ST131 lineage and, at a lower rate, to ST410/A. Regarding K. pneumoniae, the three international lineages ST15, ST147, and ST280 were detected among selected isolates. Conclusions: Different ESBL variants of CTX-M (especially CTX-M-15) and SHV-type (specially SHV-12) were detected among CTX/CAZ^RE. coli and K. pneumoniae isolates, in occasions associated with carbapenemase genes (bla_KPC2/3 gene).

High-risk clones of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolated from the University Hospital Establishment of Oran, Algeria (2011-2012)

The purpose of the study was to characterize the resistome, virulome, mobilome and Clustered Regularly Interspaced Short Palindromic Repeats-associated (CRISPR-Cas) system of extended-spectrum β-lactamase producing Klebsiella pneumoniae (ESBL-KP) clinical isolates and to determine their phylogenetic relatedness. The isolates were from Algeria, isolated at the University Hospital Establishment of Oran, between 2011 and 2012. ESBL-KP isolates (n = 193) were screened for several antibiotic resistance genes (ARGs) using qPCR followed by Pulsed-Field Gel Electrophoresis (PFGE). Representative isolates were selected from PFGE clusters and subjected to whole-genome sequencing (WGS). Genomic characterization of the WGS data by studying prophages, CRISPR-Cas systems, Multi-Locus Sequence Typing (MLST), serotype, ARGs, virulence genes, plasmid replicons, and their pMLST. Phylogenetic and comparative genomic were done using core genome MLST and SNP-Based analysis. Generally, the ESBL-KP isolates were polyclonal. The whole genome sequences of nineteen isolates were taken of main PFGE clusters. Sixteen sequence types (ST) were found including high-risk clones ST14, ST23, ST37, and ST147. Serotypes K1 (n = 1), K2 (n = 2), K3 (n = 1), K31 (n = 1), K62 (n = 1), and K151 (n = 1) are associated with hyper-virulence. CRISPR-Cas system was found in 47.4%, typed I-E and I-E*. About ARGs, from 193 ESBL-KP, the majority of strains were multidrug-resistant, the CTX-M-1 enzyme was predominant (99%) and the prevalence of plasmid-mediated quinolone resistance (PMQR) genes was high with aac(6')-lb-cr (72.5%) and qnr's (65.8%). From 19 sequenced isolates we identified ESBL, AmpC, and carbapenemase genes: blaCTX-M-15 (n = 19), blaOXA-48 (n = 1), blaCMY-2 (n = 2), and blaCMY-16 (n = 2), as well as non-ESBL genes: qnrB1 (n = 12), qnrS1 (n = 1) and armA (n = 2). We found IncF, IncN, IncL/M, IncA/C2, and Col replicon types, at least once per isolate. This study is the first to report qnrS in ESBL-KP in Algeria. Our analysis shows the concerning co-existence of virulence and resistance genes and would support that genomic surveillance should be a high priority in the hospital environment.

Prevalence and molecular epidemiology of mcr-1-positive Klebsiella pneumoniae in healthy adults from China

OBJECTIVES

To investigate the nationwide prevalence of mcr-1-positive Klebsiella pneumoniae (MCRPKP) strains among healthy adults in China and identify their phenotypic and genomic characterizations.

METHODS

A total of 7401 rectal swab samples were collected from healthy individuals in 30 hospitals located in 30 provinces and municipalities of mainland China in 2016. Colistin-resistant bacteria were enriched in colistin-supplemented lysogeny broth. MCRPKP strains were isolated and characterized with MALDI-TOF MS, PCR analysis and antimicrobial susceptibility testing. The genomic characteristics of MCRPKP strains were determined by WGS and bioinformatics analysis.

RESULTS

Seven MCRPKP strains and one mcr-1-positive Klebsiella variicola strain were selectively isolated from six locales (three from Henan and one from each of Tianjin, Jiangxi, Yunnan, Gansu and Tibet). Antimicrobial susceptibility testing results indicated that all mcr-1-positive strains were susceptible to meropenem, aztreonam and ceftazidime/avibactam. WGS analysis suggested these strains belonged to seven distinct STs: ST15, ST1425, ST1462, ST273, ST307, ST391 and ST37-SLV. mcr-1 genes were carried by diverse plasmids, including IncHI2 (n = 3), IncX4 (n = 2), IncHI2/IncN (n = 1), IncFIB (n = 1) and one other plasmid type. Two ST15 strains harboured both mcr-1 and mcr-8 genes, which has not been reported before.

CONCLUSIONS

Our data indicated a low prevalence of mcr-1-positive Klebsiella strains (0.11%, 8/7401) in healthy individuals in mainland China and most of these strains remained susceptible to clinically important antibiotics. The prevalence and coexistence of mcr-1 and mcr-8 in K. pneumoniae may further threaten public health through either the food chain or environmental routes.

Fecal Carriage and Epidemiology of Extended-Spectrum Beta-Lactamase/Carbapenemases Producing Enterobacterales Isolates in Bulgarian Hospitals

The gastrointestinal tract is an important reservoir of extended spectrum beta-lactamase (ESBL)/carbapenemase-producing Enterobacterales isolates. This study included patients from two Bulgarian hospitals. Overall, 98 ESBL producers (including 68 Escherichia coli and 20 Klebsiella pneumoniae isolates) were detected among 99 hospitalized patients, 212 patients at admission, and 92 hospital staff in 42.4%, 24.5%, and 4%, respectively. We observed bla_CTX-M-15 in 47% of isolates, bla_CTX-M-3 in 39% and bla_CTX-M-14 in 11%. Three bla_CTX-M-15 positive isolates were also bla_KPC-2 positive. High transferability was detected for bla_CTX-M-3 carrying plasmids (55%) with L/M and I1 replicon plasmids, followed by CTX-M-14 (36.4%) and CTX-M-15 (27.9%) with IncF plasmids. BlaKPC-2 was carried by FIIAs plasmids. Epidemiology typing revealed 8 K. pneumoniae ST types—ST15(8/20), ST17(4/20), ST37(2/20) and 9 E. coli ST types—ST131 (30.9%, 21/68), ST38 (8/68), ST95(7/68) and ST316(7/68). All ST131 isolates but one was from the highly virulent epidemic clone O25bST131. This is the first report in Bulgaria about ESBL/carbapenemase faecal carriage. We observed high ESBL/carbapenemases prevalence. A predominant number of isolates were members of highly epidemic and virulent PanEuropean clones ST15 K. pneumoniae and O25bST131 E. coli. High antibiotics usage during the COVID pandemic will worsen the situation. Routine screenings and strict infection control measures should be widely implemented.

Multidrug-resistant Klebsiella pneumoniae harboring extended spectrum β-lactamase encoding genes isolated from human septicemias

Klebsiella pneumoniae is a major pathogen implicated in nosocomial infections. Extended-spectrum β-lactamase (ESBL)-producing K. pneumoniae isolates are a public health concern. We aim to characterize the type of β-lactamases and the associated resistance mechanisms in ESBL-producing K. pneumoniae isolates obtained from blood cultures in a Portuguese hospital, as well as to determine the circulating clones. Twenty-two cefotaxime/ceftazidime-resistant (CTX/CAZ^R) K. pneumoniae isolates were included in the study. Identification was performed by MALDI-TOF MS and the antimicrobial susceptibility testing by disk-diffusion. The screening test for ESBL-production was performed and ESBL-producer isolates were further characterized. The presence of different beta-lactamase genes (bla_CTX-M, bla_SHV, bla_TEM, bla_KPC, bla_NDM,bla_VIM,bla_OXA-48,bla_CMY-2, bla_DHA-1,bla_FOX,bla_MOX, and bla_ACC) was analyzed by PCR/sequencing in ESBL-producer isolates, as well as the presence of other resistance genes (aac(6’)-Ib-cr, tetA/B, dfrA, qnrA/B/S, sul1/2/3) or integron-related genes (int1/2/3). Multilocus-sequence-typing (MLST) was performed for selected isolates. ESBL activity was detected in 12 of the 22 CTX/CAZ^RK. pneumoniae isolates and 11 of them carried the bla_CTX-M-15 gene (together with bla_TEM)_, and the remaining isolate carried the bla_SHV-106 gene. All the bla_CTX-M-15 harboring isolates also contained a bla_SHV gene (bla_SHV-1, bla_SHV-11 or bla_SHV-27 variants). Both bla_SHV-27 and bla_SHV-106 genes correspond to ESBL-variants. Two of the CTX-M-15 producing isolates carried a carbapenemase gene (bla_KPC2/3 and bla_OXA-48) and showed imipenem resistance. The majority of the ESBL-producing isolates carried the int1 gene, as well as sulphonamide-resistance genes (sul2 and/or sul3); the tetA gene was detected in all eight tetracycline-resistant isolates. Three different genetic lineages were found in selected isolates: ST348 (one CTX-M-15/TEM/SHV-27/KPC-2/3-producer isolate), ST11 (two CTX-M-15/TEM/SHV-1- and CTX-M-15-TEM-SHV-11-OXA-48-producer isolates) and ST15 (one SHV-106/TEM-producer isolate). ESBL enzymes of CTX-M-15 or SHV-type are detected among blood K. pneumoniae isolates, in some cases in association with carbapenemases of KPC or OXA-48 type.

ESBL-producing Klebsiella pneumoniae in a University hospital: Molecular features, diffusion of epidemic clones and evaluation of cross-transmission

The worldwide spread of Klebsiella pneumoniae producing extended-spectrum β-lactamase (ESBL-Kp) is a significant threat. Specifically, various pandemic clones of ESBL-Kp are involved in hospital outbreaks and caused serious infections. In that context, we assessed the phenotypic and molecular features of a collection of ESBL-Kp isolates in a French university hospital and evaluated the occurrence of potential cross-transmissions. Over a 2-year period (2017-2018), 204 non-duplicate isolates of ESBL-Kp were isolated from clinical (n = 118, 57.8%) or screening (n = 86, 42.2%) sample cultures. These isolates were predominantly resistant to cotrimoxazole (88.8%) and ofloxacin (82.8%) but remained susceptible to imipenem (99.3%) and amikacin (93.8%). CTX-M-15 was the most frequent ESBL identified (83.6%). Multilocus sequence typing and pulse-field gel electrophoresis analysis showed an important genetic variability with 41 sequence types (ST) and 50 pulsotypes identified, and the over representation of the international epidemic clones ST307 and ST405. An epidemiological link attesting probable cross-transmission has been identified for 16 patients clustered in 4 groups during the study period. In conclusion, we showed here the dissemination of pandemic clones of ESBL-Kp in our hospital on a background of clonal diversity.

Clonal Dissemination of KPC-2, VIM-1, OXA-48-Producing Klebsiella pneumoniae ST147 in Katowice, Poland

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is an important bacterium of nosocomial infections. In this study, CRKP strains, which were mainly isolated from fecal samples of 14 patients in three wards of the hospital in the Silesia Voivodship, rapidly increased from February to August 2018. Therefore, we conducted microbiological and molecular studies of the CRKP isolates analyzed. Colonized patients had critical underlying diseases and comorbidities; one developed bloodstream infection, and five died (33.3%). Antibiotic susceptibilities were determined by the E-test method. A disc synergy test confirmed carbapenemase production. CTX-Mplex PCR evaluated the presence of resistance genes bla_CTX-M-type, bla_CTX-M-1, bla_CTX-M-9, and the genes bla_SHV, bla_TEM, bla_KPC-2, bla_NDM-1, bla_OXA-48, bla_IMP, and bla_VIM-1 was detected with the PCR method. Clonality was evaluated by Multi Locus Sequence Typing (MLST) and Pulsed Field Gel Electrophoresis (PFGE). Six (40%) strains were of XDR (Extensively Drug-Resistant) phenotype, and nine (60%) of the isolates exhibited MDR (Multidrug-Resistant) phenotype. The range of carbapenem minimal inhibitory concentrations (MICs, μg/mL) was as follows doripenem (16 to >32), ertapenem (> 32), imipenem (4 to > 32), and meropenem (> 32). PCR and sequencing confirmed the bla_CTX-M-15, bla_KPC-2, bla_OXA-48, and bla_VIM-1 genes in all strains. The isolates formed one large PFGE cluster (clone A). MLST assigned them to the emerging high-risk clone of ST147 (CC147) pandemic lineage harboring the bla_OXA-48 gene. This study showed that the K. pneumoniae isolates detected in the multi-profile medical centre in Katowice represented a single strain of the microorganism spreading in the hospital environment.

Genomic analysis revealing the resistance mechanisms of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolated from pig and humans in Malaysia

Extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has been associated with a wide range of infections in humans and animals. The objective of this study was to determine the genomic characteristics of two multiple drug resistant, ESBLs-producing K. pneumoniae strains isolated from a swine in 2013 (KP2013Z28) and a hospitalized patient in 2014 (KP2014C46) in Malaysia. Genomic analyses of the two K. pneumoniae strains indicated the presence of various antimicrobial resistance genes associated with resistance to β-lactams, aminoglycosides, colistin, fluoroquinolones, phenicols, tetracycline, sulfonamides, and trimethoprim, corresponding to the antimicrobial susceptibility profiles of the strains. KP2013Z28 (ST25) and KP2014C46 (ST929) harbored 5 and 2 genomic plasmids, respectively. The phylogenomics of these two Malaysian K. pneumoniae, with other 19 strains around the world was determined based on SNPs analysis. Overall, the strains were resolved into five clusters that comprised of strains with different resistance determinants. This study provided a better understanding of the resistance mechanisms and phylogenetic relatedness of the Malaysian strains with 19 strains isolated worldwide. This study also highlighted the needs to monitor the usage of antibiotics in hospital settings, animal husbandry, and agricultural practices due to the increase of β-lactam, aminoglycosides, tetracycline, and colistin resistance among pathogenic bacteria for better infection control.

Whole-Genome Sequencing of Clinically Isolated Carbapenem-Resistant Enterobacterales Harboring mcr Genes in Thailand, 2016-2019

Mobile colistin-resistant genes (mcr) have become an increasing public health concern. Since the first report of mcr-1 in Thailand in 2016, perspective surveillance was conducted to explore the genomic characteristics of clinical carbapenem-resistant Enterobacterales (CRE) isolates harboring mcr in 2016-2019. Thirteen (0.28%) out of 4,516 CRE isolates were found to carry mcr genes, including 69.2% (9/13) of E. coli and 30.8% (4/13) of K. pneumoniae isolates. Individual mcr-1.1 was detected in eight E. coli (61.5%) isolates, whereas the co-occurrence of mcr-1.1 and mcr-3.5 was seen in only one E. coli isolate (7.7%). No CRE were detected carrying mcr-2, mcr-4, or mcr-5 through to mcr-9. Analysis of plasmid replicon types carrying mcr revealed that IncX4 was the most common (61.5%; 8/13), followed by IncI2 (15.4%; 2/13). The minimum inhibitory concentration values for colistin were in the range of 4-16 μg/ml for all CRE isolates harboring mcr, suggesting they have 100% colistin resistance. Clermont phylotyping of nine mcr-harboring carbapenem-resistant E. coli isolates demonstrated phylogroup C was predominant in ST410. In contrast, ST336 belonged to CC17, and the KL type 25 was predominant in carbapenem-resistant K. pneumoniae isolates. This report provides a comprehensive insight into the prevalence of mcr-carrying CRE from patients in Thailand. The information highlights the importance of strengthening official active surveillance efforts to detect, control, and prevent mcr-harboring CRE and the need for rational drug use in all sectors.

Confronting Ceftolozane-Tazobactam Susceptibility in Multidrug-Resistant Enterobacterales Isolates and Whole-Genome Sequencing Results (STEP Study)

Ceftolozane-tazobactam (C/T) is frequently used for infections caused by multidrug-resistant (MDR)-Enterobacterales isolates. Whole-genome sequencing (WGS, Illumina-Hiseq 4000/NovaSeq 6000, OGC, UK) was used to study the population structure, the resistome and the virulome of C/T-susceptible and -resistant MDR Escherichia spp. (n=30) and Klebsiella spp. (n=78) isolates, recovered from lower respiratory, intra-abdominal and urinary tract infections of ICU patients from 11 Portuguese Hospitals (STEP study, 2017-2018). Minimum inhibitory concentrations (MICs) were determined (ISO-broth microdilution, breakpoints EUCAST-2020). In Escherichia spp., a weak concordance between the phenotypic and the WGS method (P=0.051) was observed in the carbapenemase detection (3/30) [bla_VIM-2 (2/3), bla_KPC-3 (1/3)]; VIM-2-Escherichia coli isolates were C/T-susceptible and only the KPC-3-Escherichia marmotae producer showed C/T-resistance. Overall, CTX-M-15-E. coli-ST131-O25:H4-H30-Rx (11/30) was the most frequent subclone, followed by CTX-M-27-E. coli-ST131-O25:H4-H30 (4/4). Moreover, a wide resistome and virulome were detected in all E. coli isolates. Among Klebsiella spp. isolates [K. pneumoniae (67/78), K. aerogenes (7/78), K. oxytoca (2/78), K. variicola (2/78)], concordance (P<0.001) was observed between the phenotypic and the genomic carbapenemase detection (21/78) [bla_KPC-3 (14/21), bla_OXA-48 (3/21), bla_OXA-181 (3/21)]. A high correlation between C/T-resistance and carbapenemase detection was established (P<0.05). Overall, a high clonal diversity was observed, mainly in KPC-3-producing K. pneumoniae isolates. An extensive resistome was detected in Klebsiella spp. isolates, whereas virulence determinants were mostly identified in carbapenemase producers (P<0.001). WGS is a powerful tool for typing characterization and microbiological study of MDR-Enterobacterales pathogens. Furthermore, carbapenemase genes are associated with C/T-resistance in Klebsiella spp., but other mechanisms might also be involved.

Multiplicity of Carbapenemase-Producers Three Years after a KPC-3-Producing K. pneumoniae ST147-K64 Hospital Outbreak

Carbapenem resistance rates increased exponentially between 2014 and 2017 in Portugal (~80%), especially in Klebsiella pneumoniae. We characterized the population of carbapanemase-producing Enterobacterales (CPE) infecting or colonizing hospitalized patients (2017-2018) in a central hospital from northern Portugal, where KPC-3-producing K. pneumoniae capsular type K64 has caused an initial outbreak. We gathered phenotypic (susceptibility data), molecular (population structure, carbapenemase, capsular type) and biochemical (FT-IR) data, together with patients' clinical and epidemiological information. A high diversity of Enterobacterales species, clones (including E. coli ST131) and carbapenemases (mainly KPC-3 but also OXA-48 and VIM) was identified three years after the onset of carbapenemases spread in the hospital studied. ST147-K64 K. pneumoniae, the initial outbreak clone, is still predominant though other high-risk clones have emerged (e.g., ST307, ST392, ST22), some of them with pandrug resistance profiles. Rectal carriage, previous hospitalization or antibiotherapy were presumptively identified as risk factors for subsequent infection. In addition, our previously described Fourier Transform infrared (FT-IR) spectroscopy method typed 94% of K. pneumoniae isolates with high accuracy (98%), and allowed to identify previously circulating clones. This work highlights an increasing diversity of CPE infecting or colonizing patients in Portugal, despite the infection control measures applied, and the need to improve the accuracy and speed of bacterial strain typing, a goal that can be met by simple and cost-effective FT-IR based typing.

Clinical and Molecular Description of a High-Copy IncQ1 KPC-2 Plasmid Harbored by the International ST15 Klebsiella pneumoniae Clone

In many parts of the world, carbapenem resistance is a serious public health concern. In Brazil, carbapenem resistance in Enterobacterales is mostly driven by the dissemination of KPC-2-producing K. pneumoniae clones. Despite being endemic in this country, only a few reports providing both clinical and genomic data are available in Brazil, which limit the understanding of the real clinical impact caused by the dissemination of different clones carrying bla_KPC-2 in Brazilian hospitals. Although several of these KPC-2-producer K. pneumoniae isolates belong to the clonal complex 258 and carry Tn4401 transposons located on large plasmids, a concomitant emergence and silent dissemination of small high-copy-number bla_KPC-2 plasmids are of importance, as described in this study. Our data identify a small high-copy-number IncQ1 KPC plasmid, its clinical relevance, and the potential for conjugative transfer into several K. pneumoniae isolates, belonging to different international lineages, such as ST258, ST101, and ST15.

This study provides the genomic characterization and clinical description of bloodstream infections (BSI) cases due to ST15 KPC-2 producer Klebsiella pneumoniae. Six KPC-K. pneumoniae isolates were recovered in 2015 in a tertiary Brazilian hospital and were analyzed by whole-genome sequencing (WGS) (Illumina MiSeq short reads). Of these, two isolates were further analyzed by Nanopore MinION sequencing, allowing complete chromosome and plasmid circularization (hybrid assembly), using Unicycler software. The clinical analysis showed that the 30-day overall mortality for these BSI cases was high (83%). The isolates exhibited meropenem resistance (MICs, 32 to 128 mg/liter), with 3/6 isolates resistant to polymyxin B. The conjugative properties of the bla_KPC-2 plasmid and its copy number were assessed by standard conjugation experiments and sequence copy number analysis. We identified in all six isolates a small (8.3-kb), high-copy-number (20 copies/cell) non-self-conjugative IncQ plasmid harboring bla_KPC-2 in a non-Tn4401 transposon. This plasmid backbone was previously reported to harbor bla_KPC-2 only in Brazil, and it could be comobilized at a high frequency (10⁻⁴) into Escherichia coli J53 and into several high-risk K. pneumoniae clones (ST258, ST15, and ST101) by a common IncL/M helper plasmid, suggesting the potential of international spread. This study thus identified the international K. pneumoniae ST15 clone as a carrier of bla_KPC-2 in a high-copy-number IncQ1 plasmid that is easily transmissible among other common Klebsiella strains. This finding is of concern since IncQ1 plasmids are efficient antimicrobial resistance determinant carriers across Gram-negative species. The spread of such carbapenemase-encoding IncQ1 plasmids should therefore be closely monitored.

IMPORTANCE In many parts of the world, carbapenem resistance is a serious public health concern. In Brazil, carbapenem resistance in Enterobacterales is mostly driven by the dissemination of KPC-2-producing K. pneumoniae clones. Despite being endemic in this country, only a few reports providing both clinical and genomic data are available in Brazil, which limit the understanding of the real clinical impact caused by the dissemination of different clones carrying bla_KPC-2 in Brazilian hospitals. Although several of these KPC-2-producer K. pneumoniae isolates belong to the clonal complex 258 and carry Tn4401 transposons located on large plasmids, a concomitant emergence and silent dissemination of small high-copy-number bla_KPC-2 plasmids are of importance, as described in this study. Our data identify a small high-copy-number IncQ1 KPC plasmid, its clinical relevance, and the potential for conjugative transfer into several K. pneumoniae isolates, belonging to different international lineages, such as ST258, ST101, and ST15.

Emerging Antimicrobial-Resistant High-Risk Klebsiella pneumoniae Clones ST307 and ST147

There is an enormous global public health burden due to antimicrobial-resistant (AMR) Klebsiella pneumoniae high-risk clones. K. pneumoniae ST307 and ST147 are recent additions to the family of successful clones in the species. Both clones likely emerged in Europe during the early to mid-1990s and, in a relatively short time, became prominent global pathogens, spreading to all continents (with the exception of Antarctica). ST307 and ST147 consist of multiple clades/clusters and are associated with various carbapenemases (i.e., KPCs, NDMs, OXA-48-like, and VIMs). ST307 is endemic in Italy, Colombia, the United States (Texas), and South Africa, while ST147 is endemic in India, Italy, Greece, and certain North African countries. Both clones have been introduced into regions of nonendemicity, leading to worldwide nosocomial outbreaks. Genomic studies showed ST307 and ST147 contain identical gyrA and parC mutations and likely obtained plasmids with bla _CTX-M-15 during the early to mid-2000s, which aided in their global distribution. ST307 and ST147 then acquired plasmids with various carbapenemases during the late 2000s, establishing themselves as important AMR pathogens in certain regions. Both clones are likely underreported due to restricted detection methodologies. ST307 and ST147 have the ability to become major threats to public health due to their worldwide distribution, ability to cause serious infections, and association with AMR, including panresistance. The medical community at large, especially those concerned with antimicrobial resistance, should be aware of the looming threat posed by emerging AMR high-risk clones such as K. pneumoniae ST307 and ST147.

Trends in antimicrobial resistance over 10 years among key bacterial pathogens from Canadian hospitals: results of the CANWARD study 2007-16

OBJECTIVES

We sought to analyse 10 years of longitudinal surveillance data (2007-16) from the CANWARD study and describe emerging trends in antimicrobial resistance for key bacterial pathogens across Canada.

METHODS

Longitudinal data from CANWARD study sites that contributed isolates every year from 2007 to 2016 were analysed to identify trends in antimicrobial resistance over time using univariate tests of trend and multivariate regression models to account for the effects of patient demographics.

RESULTS

Statistically significant increases occurred in the proportion of Escherichia coli isolates resistant to extended-spectrum cephalosporins, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole and ciprofloxacin. Similarly, the proportion of Klebsiella pneumoniae isolates resistant to extended-spectrum cephalosporins, amoxicillin/clavulanate, trimethoprim/sulfamethoxazole, ciprofloxacin and carbapenems increased during the study. The proportion of Enterobacter cloacae isolates resistant to ceftazidime and trimethoprim/sulfamethoxazole increased. The proportion of both ESBL-positive E. coli and K. pneumoniae (including bloodstream isolates) increased significantly between 2007 and 2016. A reduction in the proportion of Pseudomonas aeruginosa that were ciprofloxacin, cefepime, colistin, amikacin and gentamicin resistant and an increase in the proportion of P. aeruginosa isolates non-susceptible to meropenem were observed. The proportion of isolates of Staphylococcus aureus non-susceptible to clarithromycin, clindamycin and trimethoprim/sulfamethoxazole decreased over time while an increase in the proportion of isolates of Streptococcus pneumoniae non-susceptible to clarithromycin, clindamycin and doxycycline was observed.

CONCLUSIONS

Increases in Enterobacteriaceae resistance to multiple classes of antimicrobials, increases in ESBL-positive E. coli and K. pneumoniae, and the small but significant increase in carbapenem-resistant K. pneumoniae were the most remarkable changes in antimicrobial resistance observed from 2007 to 2016 in Canada.

Horizontal Plasmid Transfer among Klebsiella pneumoniae Isolates Is the Key Factor for Dissemination of Extended-Spectrum β-Lactamases among Children in Tanzania

Horizontal spread of plasmids carrying multiple resistance genes is considered an important mechanism behind the global health problem caused by multidrug-resistant bacteria. Nevertheless, knowledge about spread of plasmids in a community is limited. Our detailed molecular analyses of K. pneumoniae isolated from hospitalized and healthy children in Tanzania disclosed an epidemic spread of a resistance plasmid. In this study population, we revealed horizontal plasmid transfer among K. pneumoniae as the key factor for dissemination of ESBLs. Traditional outbreak investigation and surveillance focus on the spread of bacterial clones, and short-read sequencing can result in erroneous plasmid composition. Our approach using long-read sequencing reveals horizontal gene transfer of antimicrobial resistance, and therefore has a potential impact on outbreak investigations and approaches to limit spread of AMR.

Increased knowledge about the role of horizontal gene transfer is key to improve our understanding of the spread of antimicrobial resistance (AMR) in human populations. We therefore studied the dissemination of the bla_CTX-M-15 extended-spectrum-β-lactamase (ESBL) gene in Klebsiella pneumoniae isolates obtained from stool samples from hospitalized children and healthy controls below 2 years of age in Dar es Salaam, Tanzania, from August 2010 to July 2011. We performed Illumina whole-genome sequencing (WGS) to characterize resistance genes, multilocus sequence type (MLST), plasmid incompatibility group (Inc), and plasmid MLST of 128 isolates of K. pneumoniae with bla_CTX-M-15 recovered from both healthy and hospitalized children. We assessed the phylogenetic relationship using single nucleotide polymorphism (SNP)-based analysis and resolved the sequences of five reference plasmids by Oxford Nanopore technology to investigate plasmid dissemination. The WGS analyses revealed the presence of a bla_CTX-M-15-positive IncFII_K5/IncR plasmid with a highly conserved backbone in 70% (90/128) of the isolates. This plasmid, harboring genes encoding resistance to most β-lactams, aminoglycosides, trimethoprim-sulfamethoxazole, and chloramphenicol, was present in phylogenetically very diverse K. pneumoniae strains (48 different MLSTs) carried by both hospitalized and healthy children. Our data strongly suggest widespread horizontal transfer of this ESBL-carrying plasmid both in hospitals and in the general population.

IMPORTANCE Horizontal spread of plasmids carrying multiple resistance genes is considered an important mechanism behind the global health problem caused by multidrug-resistant bacteria. Nevertheless, knowledge about spread of plasmids in a community is limited. Our detailed molecular analyses of K. pneumoniae isolated from hospitalized and healthy children in Tanzania disclosed an epidemic spread of a resistance plasmid. In this study population, we revealed horizontal plasmid transfer among K. pneumoniae as the key factor for dissemination of ESBLs. Traditional outbreak investigation and surveillance focus on the spread of bacterial clones, and short-read sequencing can result in erroneous plasmid composition. Our approach using long-read sequencing reveals horizontal gene transfer of antimicrobial resistance, and therefore has a potential impact on outbreak investigations and approaches to limit spread of AMR.

Molecular characteristics of extended-spectrum β-lactamase-producing Klebsiella pneumoniae in Japan: Predominance of CTX-M-15 and emergence of hypervirulent clones

OBJECTIVE

To provide data on the molecular characteristics of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae clinical isolates in Japan.

METHODS

A total of 100 clinical isolates of ESBL-producing K. pneumoniae collected throughout Japan between June and July 2018 were studied. ESBL genes were analyzed using PCR and DNA sequencing. Transferability of ESBL genes was investigated by conjugation experiments. Plasmid replicon types, virulence genes (rmpA, rmpA2, iucA, iroB, and peg-344) associated with hypervirulent K. pneumoniae (hvKp), and capsule types were detected using PCR. Genotyping was performed using multilocus sequence typing.

RESULTS

All ESBL-producing isolates carried bla_CTX-M genes. The most predominant CTX-M-type identified was CTX-M-15 (n=55). We identified 24 sequence types (STs) among the CTX-M-15 producers, with ST25 (n=8) being the most common. Most of the transconjugants carrying bla_CTX-M-15 contained the FIIk replicon. Of the 100 ESBL-producing isolates, 31 were hvKp defined by the presence of the virulence genes. These ESBL-producing hvKp isolates belonged to eight STs (STs 23, 25, 36, 65, 86, 268, 412, and 4492), with five capsule types (K1, K2, K20, K57, and undefined).

CONCLUSIONS

CTX-M-15 was the predominant ESBL among K. pneumoniae isolates from Japan. This study shows that ESBL-producing hvKp strains comprising various clones are emerging in Japan.

Molecular characterization of Danish ESBL/AmpC-producing Klebsiella pneumoniae from bloodstream infections, 2018

OBJECTIVES

The aim of the study was to molecularly characterize third-generation cephalosporin-resistant Klebsiella pneumoniae isolated from bloodstream infections in Denmark in 2018 using whole-genome sequencing (WGS) data, and to compare these isolates to the most common clones detected in 2006 and 2008.

METHODS

Sixty-two extended-spectrum beta-lactamase (ESBL)/AmpC-producing K. pneumoniae isolates from Danish blood cultures from 2018 were analysed using WGS to obtain multilocus sequence typing (MLST), core genome MLST (cgMLST), resistance profile and phylogeny. These were compared to the most common ESBL K. pneumoniae clones detected in 2006 and 2008.

RESULTS

The most common ESBL clone was ST15 CTX-M-15, the DHA-1 enzyme was the most common in AmpC isolates, and the OXA-48-like group was the most common carbapenemase. Thirty-nine different sequence types (STs) were found, with the most frequent being ST14, ST15 and ST37, accounting for 24% of the isolates. The isolates were subdivided into 55 complex types (CTs) of which 49 were singletons, with the most frequent being ST14-CT2080. Two of the CTX-M-15-producing isolates from 2018 belonged to the ST15-CT105/CT3078 clone, which was first detected in 2006.

CONCLUSIONS

The ESBL/AmpC K. pneumoniae isolates detected in Danish blood cultures belonged to many different types. No dominant clones were circulating in Danish hospitals, but the ST15-CT105/CT3078 CTX-M-15 K. pneumoniae clone was seen 13 years after its first detection.

Identification of a newly isolated lytic bacteriophage against K24 capsular type, carbapenem resistant Klebsiella pneumoniae isolates

The increasing incidence of carbapenemase-producing K. pneumoniae strains (CP-Kps) in the last decade has become a serious global healthcare problem. Therapeutic options for the treatment of emerging hospital clones have drastically narrowed and therefore novel approaches must be considered. Here we have isolated and characterized a lytic bacteriophage, named vB_KpnS_Kp13, that was effective against all Verona integron-encoded metallo-β-lactamase (VIM) producing K. pneumoniae isolates originating from hospital samples (urine, blood, sputum and faeces), belonging to the ST15 clonal lineage and expressing the K24 capsule. Morphological characterization of vB_KpnS_Kp13 showed that the newly identified phage belonged to the Siphoviridae family, and phylogenetic analysis showed that it is part of a distinct clade of the Tunavirinae subfamily. Functional analysis revealed that vB_KpnS_Kp13 had relatively short latent period times (18 minutes) compared to other K. pneumoniae bacteriophages and could degrade biofilm by more than 50% and 70% in 24 and 48 hours respectively. Complete in vivo rescue potential of the new phage was revealed in an intraperitoneal mouse model where phages were administered intraperitoneally 10 minutes after bacterial challenge. Our findings could potentially be used to develop specific anti-CP-Kps bacteriophage-based therapeutic strategies against major clonal lineages and serotypes.

Emergence of Five Genetic Lines ST395NDM-1, ST13OXA-48, ST3346OXA-48, ST39CTX-M-14, and Novel ST3551OXA-48 of Multidrug-Resistant Clinical Klebsiella pneumoniae in Russia

Aims: The objective of this study was phenotypic and genotypic characterization of antibacterial-resistant Klebsiella pneumoniae clinical strains isolated in Moscow Transplantology Intensive Care Unit in 2017-2019. Results: Major strains among K. pneumoniae (n = 63) isolated from 30 patients were recognized as extensive drug-resistant (n = 55) pathogens, and remaining strains were recognized as multidrug-resistant (n = 8) pathogens. The beta-lactamase genes bla_{SHV-1,-2a,-11,-27,-67,-187} (n = 63), bla_CTX-M-14,-15 (n = 61), bla_TEM-1 (n = 54), bla_OXA-48 (n = 52), and bla_NDM-1 (n = 2), as well as class 1 integrons (n = 19) carried gene cassette arrays aacA4 (n = 2), dfrA1-orfC (n = 6), aadB-aadA1 (n = 9), dfrA15-aadA1 (n = 3), and dfrA12-orfF-aadA2 (n = 1) were identified in the strains. All strains carried four virulence genes: wabG, fimH, uge, and allS, but two strains had additionally kfu gene. Six known sequence types (STs) of K. pneumoniae ST395 (n = 44), ST377 (n = 3), ST307 (n = 4), ST13 (n = 2), ST39 (n = 2), ST3346 (n = 1), and a novel sequence-type ST3551 (n = 7) were identified. Phylogenetic analysis showed that ST3551 belonged to the cluster of clonal group CG147, and the remaining six STs to the another cluster consisting of four subgroups. The emergence of K. pneumoniae genetic lines carrying epidemiologically significant beta-lactamase genes ST395^NDM-1, ST13^OXA-48, ST3346^{OXA-48/CTX-M-14}, ST3551^OXA-48, and ST39^CTX-M-14 was the first case of detection in Russia. Conclusion: The emergence of novel carbapenemase-producing K. pneumoniae genetic lines in Russia highlights the global negative tendency of multidrug-resistant pathogens spread in high-technological medical centers.

First Report of Extended-Spectrum Betalactamase-Producing Klebsiella pneumoniae Among Fecal Carriage in Iran: High Diversity of Clonal Relatedness and Virulence Factor Profiles

Increasing rate of silent intestinal carriers with extended-spectrum betalactamase (ESBL)-producing Klebsiella pneumonia (ESBL-KP) has given rise to a serious healthcare problem in clinical settings. Various epidemiological studies are being conducted to determine clonal relatedness among carriers. In this study, we investigated the intestinal carriage of ESBL-KP and clonal relatedness among ESBL-KP isolated from fecal carriage in Iran for the first time. A total of 120 rectal swabs (RSs) were collected including 61 from inpatients of intensive care unit and 59 from outpatients. ESBL-KP screening was performed using MacConkey agar supplemented with cefotaxime. PCR was done for detection of ESBL, carbapenemase, and virulence factor genes. Conjugation experiments and PCR-based replicon typing were performed. Clonal relatedness was investigated by multilocus sequence typing (MLST) and multiple locus variable number tandem repeat analysis (MLVA). Out of a total of 120 RSs, 18.3% (22/120) ESBL-KP were isolated. The rate of bla_CTXM-15 was 81%. ompk35 was the most prevalent virulence gene detected in 86.3% of the isolates. In conjugation experiments, three out of five tested isolates had conjugative plasmids. The most prevalent plasmid types belonged to IncL/M, IncA/C, and Inc FII. The MLST analysis showed that the main sequence types (STs) identified among ESBL-KP isolates were ST147, ST15, and ST16. The isolates were characterized into 4 miniclusters and 11 singletons using MLVA. High heterogeneity among ESBL-KP isolates indicated that this bacterium could be colonized in different sites and easily transferred. Screening of carriers in hospitals and community could help in controlling of infection in the healthcare and community settings.

Molecular characterization of extended-spectrum β-lactamase-producing Klebsiella pneumoniae from a Malaysian hospital

Multidrug-resistant (MDR) and extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae associated with nosocomial infections have caused serious problems in antibiotic management with limited therapeutic choices. This study aimed to determine the genotypic and phenotypic characteristics of K. pneumoniae strains isolated from a tertiary hospital in Malaysia. Ninety-seven clinical K. pneumoniae strains were analyzed for antimicrobial susceptibility, all of which were sensitive to amikacin and colistin (except one strain), while 31.9 % and 27.8 % were MDR and ESBL producers, respectively. PCR and DNA sequencing of the amplicons indicated that the majority of MDR strains (26/27) were positive for blaTEM, followed by blaSHV (24/27), blaCTX-M-1 group (23/27), blaCTX-M-9 group (2/27), and mcr-1 (1/27). Thirty-seven strains were hypervirulent and PCR detection of virulence genes showed 38.1 %, 22.7 %, and 16.5 % of the strains were positive for K1, wabG, and uge genes, respectively. Genotyping by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) showed that these strains were genetically diverse and heterogeneous. Sequence types, ST23, ST22, and ST412 were the predominant genotypes. This is the first report of colistin-resistant K. pneumoniae among clinical strains associated with mcr-1 plasmid in Malaysia. The findings in this study have contributed to the effort in combating the increase in antimicrobial resistance by providing better understanding of genotypic characteristics and resistance mechanisms of the organisms.

Intestinal carriage of extended-spectrum beta-lactamase-producing Enterobacteriaceae at admission in a Portuguese hospital

To evaluate the prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae fecal carriers at admission in a Portuguese hospital and to determine the epidemiology and antimicrobial resistance patterns of ESBL-producing isolates. During a 2-month period, rectal swabs were collected at hospital admission from 151 at-risk patients. In addition, 48 rectal swabs were obtained from weekly screenings of 37 patients hospitalized for > 48 h. All ESBL/carbapenemase-producing isolates were tested for antimicrobial susceptibility and characterized by PFGE and MLST. The prevalence of ESBL producers at hospital admission was 17% and 24% among at-risk patients hospitalized for > 48 h, while the prevalence of carbapenemase producers was 3% in both cases. Most of the isolates were Escherichia coli (54%) and Klebsiella pneumoniae (41%). The most common ESBL identified was CTX-M-15 (n = 17/34; 50%), followed by CTX-M-27 (n = 10; 29%), CTX-M-33 (n = 4; 12%), SHV-12 (n = 2), and CTX-M-55 (n = 1). The 20 E. coli isolates were distributed into 16 PFGE types and nine sequence types (ST), with 60% of the isolates belonging to ST131. The 15 K. pneumoniae were grouped into 12 PFGE types and nine STs, with three STs (ST17, ST449, ST147) corresponding to 60% of the isolates. A high proportion of isolates showed resistance to ciprofloxacin (86%), trimethoprim-sulfamethoxazole (68%), tobramycin (57%), and gentamicin (43%). All isolates remained susceptible to fosfomycin. A high prevalence of ESBL-producing Enterobacteriaceae was found at hospital admission among at-risk patients and > 50% of the isolates showed resistance to first-line antibiotics for the treatment of lower urinary tract infections, leaving fosfomycin as an alternative.

The Inc FII Plasmid and its Contribution in the Transmission of blaNDM-1 and blaKPC-2 in Klebsiella pneumoniae in Egypt

The emergence of bla_KPC-2 and bla_NDM-1 producing Klebsiella pneumoniae represents a great problem in many Egyptian hospitals. One hundred and twenty-six K. pneumoniae isolates from patients admitted to Assiut University Hospital were identified by an API20E kit. Carbapenemase-producing K. pneumoniae (CPKP) was detected by the modified carbapenem inactivation method (mCIM), the EDTA-modified carbapenem inactivation method (eCIM), and an E-test. Based on the polymerase chain reaction, all isolates were negative for bla-_VIM-1 and bla-_IMP-1, fifteen of these isolates were positive for both bla_KPC-2 and bla_NDM-1, two isolates were positive for bla_KPC-2 only, and twenty-eight isolates were positive for bla-_NDM-1 only. Although one isolate was positive for the string test, all CPKP isolates were negative for capsular genes. Only 71.1% of CPKP transferred their plasmids to their corresponding transconjugants (E. coli J53). The resistance patterns of the clinical isolates and their transconjugates were similar, except for 12 isolates, which showed differences with their transconjugates in the resistance profile of four antibiotics. Molecular typing of the plasmids based on replicon typing showed that Inc FIIK and FII plasmids predominated in isolates and their transconjugants carrying bla_KPC-2 and/or bla_NDM-1. Conjugative Inc FII plasmids play an important role in the spread of CPKP, and their recognition is essential to limit their spread.

Characterization of Klebsiella pneumoniae Coproducing KPC and NDM-1 Carbapenemases from Turkey

Aims: The emergence of multidrug-resistant and carbapenem-resistant Klebsiella pneumoniae has became a major public health threat. In this study, we describe the characteristics of isolates coproducing KPC and NDM-1 carbapenemases from patients hospitalized at an emergency unit in Ankara, Turkey, between January and August 2018. The isolates were characterized by antibiogram susceptibility, carbapenemase and extended-spectrum beta-lactamase production, plasmid-mediated colistin (COL) resistance, and high-level aminoglycoside resistance. Pulsed field gel electrophoresis (PFGE), sequencing, wzi typing, multilocus sequence typing, and plasmid analysis were used to investigate the epidemiological relationship between the isolates. Results: All isolates were found to be resistant to amoxicillin-clavulanic acid, piperacillin-tazobactam, cefotaxime, cefoxitin, cefuroxime, ceftazidime, cefepime, imipenem, meropenem, ertapenem, amikacin, gentamicin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole. The minimum inhibitory concentration values for imipenem, meropenem, and ertapenem were >32 μg/mL, and >256 μg/mL for amikacin and gentamicin, and two isolates were found to be susceptible to both tigecycline and COL. All strains were positive for SHV, CTX-M, and rmtC, and negative for mcr-1 genes. A/C and FIIA_S plasmids were found in all isolates. All isolates had the same PFGE pattern: wzi type 93 and ST15. Conclusion: Here, we have documented the characteristics of KPC- and NDM-1-coproducing isolates that harbored SHV, CTX-M, and rmtC and were typed as wzi 93 and ST15. We conclude that continuous monitoring of carbapenemases for unusual carbapenemase production is crucial to prevent the spread of these powerful isolates.

Understanding the Epidemiology of Multi-Drug Resistant Gram-Negative Bacilli in the Middle East Using a One Health Approach

In the last decade, extended-spectrum cephalosporin and carbapenem resistant Gram-negative bacilli (GNB) have been extensively reported in the literature as being disseminated in humans but also in animals and the environment. These resistant organisms often cause treatment challenges due to their wide spectrum of antibiotic resistance. With the emergence of colistin resistance in animals and its subsequent detection in humans, the situation has worsened. Several studies reported the transmission of resistant organisms from animals to humans. Studies from the middle east highlight the spread of resistant organisms in hospitals and to a lesser extent in livestock and the environment. In view of the recent socio-economical conflicts that these countries are facing in addition to the constant population mobilization; we attempt in this review to highlight the gaps of the prevalence of resistance, antibiotic consumption reports, infection control measures and other risk factors contributing in particular to the spread of resistance in these countries. In hospitals, carbapenemases producers appear to be dominant. In contrast, extended spectrum beta lactamases (ESBL) and colistin resistance are becoming a serious problem in animals. This is mainly due to the continuous use of colistin in veterinary medicine even though it is now abandoned in the human sphere. In the environment, despite the small number of reports, ESBL and carbapenemases producers were both detected. This highlights the importance of the latter as a bridge between humans and animals in the transmission chain. In this review, we note that in the majority of the Middle Eastern area, little is known about the level of antibiotic consumption especially in the community and animal farms. Furthermore, some countries are currently facing issues with immigrants, poverty and poor living conditions which has been imposed by the civil war crisis. This all greatly facilitates the dissemination of resistance in all environments. In the one health concept, this work re-emphasizes the need to have global intervention measures to avoid dissemination of antibiotic resistance in humans, animals and the environment in Middle Eastern countries.