Dataset Information

Plasmid-Mediated Antibiotic Resistance and Virulence in Gram-negatives: the Klebsiella pneumoniae Paradigm.

ABSTRACT: Plasmids harbor genes coding for specific functions including virulence factors and antibiotic resistance that permit bacteria to survive the hostile environment found in the host and resist treatment. Together with other genetic elements such as integrons and transposons, and using a variety of mechanisms, plasmids participate in the dissemination of these traits resulting in the virtual elimination of barriers among different kinds of bacteria. In this article we review the current information about physiology and role in virulence and antibiotic resistance of plasmids from the gram-negative opportunistic pathogen Klebsiella pneumoniae. This bacterium has acquired multidrug resistance and is the causative agent of serious communityand hospital-acquired infections. It is also included in the recently defined ESKAPE group of bacteria that cause most of US hospital infections.

SUBMITTER: Ramirez MS

PROVIDER: S-EPMC4335354 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Klebsiella pneumoniae poses a critical challenge to clinical and public health. Along with conjugative plasmids, nonconjugative resistance or virulence plasmids associated with carbapenem-resistant K. pneumoniae (CRKP), hypervirulent K. pneumoniae (hvKP), and even carbapenem-resistant and hypervirulent K. pneumoniae (CR-hvKP) strains have been spreading globally. In this study, a clinical CRKP strain KP2648 was isolated, and the transferability of its plasmids was assessed using conjugation experiments. The transconjugants were characterized by polymerase chain reaction (PCR) detection, XbaI and S1-pulsed-field gel electrophoresis (PFGE), and/or whole-genome sequencing. Genetically modified IncN3 plasmids were employed to elucidate the self-transferability and the mobilization mechanisms. KP2648 has three natural plasmids: a nonconjugative IncFIB/IncHI3B virulence plasmid, a nonconjugative IncFII/IncR carbapenem-resistant plasmid, and a self-transferable IncN3 plasmid with a high conjugation frequency (7.54 ± 1.06) × 10-1. The IncN3 plasmid could mobilize the coexisting nonconjugative virulence/resistance plasmids either directly or by employing intermediate E. coli with two forms: a hybrid plasmid fused with IncN3 or a cotransfer with the helper plasmid, IncN3. Various mobile genetic elements, including ISKpn74, ISKpn14, IS26, ISShes11, ISAba11, and Tn3, are involved in the genetic transposition of diverse hybrid plasmids and the cotransfer process during the intra/interspecies transmission. IMPORTANCE Nowadays, the underlying mobilization mechanism and evolutionary processes of nonconjugative virulence or resistance plasmids in Klebsiella pneumoniae remain poorly understood. Our study revealed the high conjugation ability of IncN3 plasmid isolated from carbapenem-resistant K. pneumoniae and confirmed its capability to mobilize the nonconjugative virulence or resistance plasmids. The self-transferable IncN3 plasmid could facilitate the transmission of pathogenicity and genetic evolution of carbapenem-resistant and hypervirulent K. pneumoniae, including hv-CRKP (virulence plasmid obtained by carbapenem-resistant K. pneumoniae) and CR-hvKP (resistance plasmid obtained by hypervirulent K. pneumoniae), warranting further monitoring.

Project description:BackgroundThe prevalence of antimicrobial resistance (AMR) among Gram-negative bacteria is alarmingly high. Reintroduction of colistin as last resort treatment in the infections caused by drug-resistant Gram-negative bacteria has led to the emergence and spread of colistin resistance. This study was designed to determine the prevalence of drug-resistance among beta-lactamase-producing strains of Escherichia coli and Klebsiella pneumoniae, isolated from the clinical specimens received at a tertiary care centre of Kathmandu, Nepal during the period of March to August, 2019.MethodsA total of 3216 different clinical samples were processed in the Microbiology laboratory of Kathmandu Model Hospital. Gram-negative isolates (E. coli and K. pneumoniae) were processed for antimicrobial susceptibility test (AST) by using modified Kirby-Bauer disc diffusion method. Drug-resistant isolates were further screened for extended-spectrum beta-lactamase (ESBL), metallo-beta-lactamase (MBL), carbapenemase and K. pneumoniae carbapenemase (KPC) production tests. All the suspected enzyme producers were processed for phenotypic confirmatory tests. Colistin resistance was determined by minimum inhibitory concentration (MIC) using agar dilution method. Colistin resistant strains were further screened for plasmid-mediated mcr-1 gene using conventional polymerase chain reaction (PCR).ResultsAmong the total samples processed, 16.4% (529/3216) samples had bacterial growth. A total of 583 bacterial isolates were recovered from 529 clinical samples. Among the total isolates, 78.0% (455/583) isolates were Gram-negative bacteria. The most predominant isolate among Gram-negatives was E. coli (66.4%; 302/455) and K. pneumoniae isolates were 9% (41/455). In AST, colistin, polymyxin B and tigecycline were the most effective antibiotics. The overall prevalence of multidrug-resistance (MDR) among both of the isolates was 58.0% (199/343). In the ESBL testing, 41.1% (n = 141) isolates were confirmed as ESBL-producers. The prevalence of ESBL-producing E. coli was 43% (130/302) whereas that of K. pneumoniae was 26.8% (11/41). Similarly, 12.5% (43/343) of the total isolates, 10.9% (33/302) of E. coli and 24.3% of (10/41) K. pneumoniae were resistant to carbapenem. Among 43 carbapenem resistant isolates, 30.2% (13/43) and 60.5% (26/43) were KPC and MBL-producers respectively. KPC-producers isolates of E. coli and K. pneumoniae were 33.3% (11/33) and 20% (2/10) respectively. Similarly, 63.6% (21/33) of the E. coli and 50% (5/10) of the K. pneumoniae were MBL-producers. In MIC assay, 2.2% (4/179) of E. coli and 10% (2/20) of K. pneumoniae isolates were confirmed as colistin resistant (MIC ≥ 4 µg/ml). Overall, the prevalence of colistin resistance was 3.1% (6/199) and acquisition of mcr-1 was 16.6% (3/18) among the E. coli isolates.ConclusionHigh prevalence of drug-resistance in our study is indicative of a deteriorating situation of AMR. Moreover, significant prevalence of resistant enzymes in our study reinforces their roles in the emergence of drug resistance. Resistance to last resort drug (colistin) and the isolation of mcr-1 indicate further urgency in infection management. Therefore, extensive surveillance, formulation and implementation of effective policies, augmentation of diagnostic facilities and incorporation of antibiotic stewardship programs can be some remedies to cope with this global crisis.

Project description:Introduction:Klebsiella pneumoniae is one of the most important infectious agents in neonates. There are "classic" and hypervirulent strains of K. pneumoniae. The "classic" non-virulent strain of K. pneumoniae, producing extended-spectrum beta-lactamases (ESBLs), is associated with nosocomial infections. Hypervirulent K. pneumoniae strains are associated with invasive infections in previously healthy adult people, and most of them exhibit antimicrobial susceptibility. The role of virulent strains of K. pneumoniae (including hv-KP) in neonatal infections is unknown. The aim of the study was the assessment of the impact of virulence factors and antibiotic resistance of K. pneumoniae strains on clinical features and outcomes of neonatal infection. Materials and Methods: Two groups of infants were enrolled. The first group consisted of 10 neonates with sepsis caused by K. pneumoniae. The second group consisted of 10 neonates with urinary tract infection (UTI) caused by K. pneumoniae. We investigated the susceptibility of K. pneumoniae isolates to antibiotics, the ability of the microorganism to produce ESBL, and virulence factors, including the rmpA gene, aerobactin, and colibactin genes. In neonates with sepsis, we investigated K. pneumoniae isolates, which was taken from the blood, in neonates with UTI-from the urine. Results: In neonates with sepsis testing of K. pneumoniae isolates for ESBL production was positive in 60% of cases, in neonates with UTI-in 40% of cases. All blood and urine ESBL producing K. pneumoniae isolates were resistant to ampicillins, including protected ones, and third-generation cephalosporins. At the same time, these isolates were sensitive to meropenem, amikacin, and ciprofloxacin. The rmpA gene was detected in four blood, and three urine K. pneumoniae isolates. In neonates with sepsis rmpA gene in two cases was detected in ESBL-producing K. pneumoniae isolates. They were infants with meningitis, and both cases were fatal. In the group of infants with UTI, the rmpA gene was detected only in K. pneumoniae isolates not producing ESBL. Aerobactin and colibactin genes were detected in two neonates with sepsis and in three neonates with UTI. In all cases, aerobactin and colibactin genes were detected only in rmpA-positive K. pneumoniae isolates. Out of three fatal outcomes, two cases were caused by hv-KP producing ESBL. Conclusion: The prevalence of virulent strains of K. pneumoniae among neonates with sepsis and other neonatal infection is higher than we think. The most severe forms of neonatal sepsis with an unfavorable outcome in our study were due to virulent strains of K. pneumoniae.

Project description:BackgroundKlebsiella pneumoniae, as a global priority pathogen, is well known for its capability of acquiring mobile genetic elements that carry resistance and/or virulence genes. Its virulence plasmid, previously deemed nonconjugative and restricted within hypervirulent K. pneumoniae (hvKP), has disseminated into classic K. pneumoniae (cKP), particularly carbapenem-resistant K. pneumoniae (CRKP), which poses alarming challenges to public health. However, the mechanism underlying its transfer from hvKP to CRKP is unclear.MethodsA total of 28 sequence type (ST) 11 bloodstream infection-causing CRKP strains were collected from Ruijin Hospital in Shanghai, China, and used as recipients in conjugation assays. Transconjugants obtained from conjugation assays were confirmed by XbaI and S1 nuclease pulsed-field gel electrophoresis, PCR detection and/or whole-genome sequencing. The plasmid stability of the transconjugants was evaluated by serial culture. Genetically modified strains and constructed mimic virulence plasmids were employed to investigate the mechanisms underlying mobilization. The level of extracellular polysaccharides was measured by mucoviscosity assays and uronic acid quantification. An in silico analysis of 2608 plasmids derived from 814 completely sequenced K. pneumoniae strains available in GenBank was performed to investigate the distribution of putative helper plasmids and mobilizable virulence plasmids.ResultsA nonconjugative virulence plasmid was mobilized by the conjugative plasmid belonging to incompatibility group F (IncF) from the hvKP strain into ST11 CRKP strains under low extracellular polysaccharide-producing conditions or by employing intermediate E. coli strains. The virulence plasmid was mobilized via four modes: transfer alone, cotransfer with the conjugative IncF plasmid, hybrid plasmid formation due to two rounds of single-strand exchanges at specific 28-bp fusion sites or homologous recombination. According to the in silico analysis, 31.8% (242) of the putative helper plasmids and 98.8% (84/85) of the virulence plasmids carry the 28-bp fusion site. All virulence plasmids carry the origin of the transfer site.ConclusionsThe nonconjugative virulence plasmid in ST11 CRKP strains is putatively mobilized from hvKP or E. coli intermediates with the help of conjugative IncF plasmids. Our findings emphasize the importance of raising public awareness of the rapid dissemination of virulence plasmids and the consistent emergence of hypervirulent carbapenem-resistant K. pneumoniae (hv-CRKP) strains.

Dataset Information

Plasmid-Mediated Antibiotic Resistance and Virulence in Gram-negatives: the Klebsiella pneumoniae Paradigm.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets