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Infection and Drug Resistance 2020is an encapsulated Gram-negative, oxidase-negative, catalase-positive, aerobic, non-motile rod that belongs to the family. This bacterium was initially classified in... (Review)
Review
is an encapsulated Gram-negative, oxidase-negative, catalase-positive, aerobic, non-motile rod that belongs to the family. This bacterium was initially classified in the genus as , until the creation of the genus in 2001. is usually found in water environments and soil, and due to its ability to convert histidine to histamine, it has been associated with histamine poisoning in humans. is an emerging entity in human infections, with several reports of virulent infections in comorbid at-risk patients. Increasing reports are potentially due to better and more precise identification tools. The objective of this article is to provide a comprehensive review of reported cases of infections, the emergent virulence of described multiresistant strains, and an overview of currently used identification methods.
PubMed: 32346300
DOI: 10.2147/IDR.S191387 -
Frontiers in Public Health 2021The genus was established in 2001. Species of and share many ecological, biochemical, clinical, and microbiological features. Given the shortcomings of available... (Review)
Review
The genus was established in 2001. Species of and share many ecological, biochemical, clinical, and microbiological features. Given the shortcomings of available technology for species identification in the clinical microbiology laboratory, are practically indistinguishable. Since the late 2000s there has been an increase in case reports of human infections. Therefore, several authors are postulating that spp. are rare and/or emerging pathogens. spp. are very similar to . The epidemiology and the clinical relevance of the human spp. infections is uncertain and further studies are required. The previous difficulties in the identification of spp. and the introduction of more precise identification techniques may explain the recent increase in the number of case reports. spp. might be rather underdiagnosed than rare or emerging pathogens.
Topics: Enterobacteriaceae Infections; Humans; Klebsiella
PubMed: 34409007
DOI: 10.3389/fpubh.2021.686789 -
Drug Resistance Updates : Reviews and... Sep 2023Carbapenems and tigecycline are crucial antimicrobials for the treatment of gram-negative bacteria infections. Recently, a novel resistance-nodulation-division (RND)...
Carbapenems and tigecycline are crucial antimicrobials for the treatment of gram-negative bacteria infections. Recently, a novel resistance-nodulation-division (RND) efflux pump gene cluster, tmexCD-toprJ, which confers resistance to tigecycline, has been discovered in animals and clinical isolates. It was reported that hospital sewage could act as a reservoir for gram-negative bacteria with high antimicrobial resistance genes. In this study, we analyzed 84 isolates of carbapenem-resistant gram-negative bacteria (CR-GNB) from hospital sewage, and identified five isolates of TMexCD-ToprJ-producing CR-GNB, including one Raoultella ornithinolytica isolate and four Pseudomonas spp. isolates. All these five isolates carried at least one carbapenem resistance gene and were resistant to multiple antibiotics. Multiple tmexCD-toprJ clusters were detected, including tmexC2D2-toprJ2, tmexC3D3-toprJ3, tmexC3.2D3.3-toprJ1b and tmexC3.2D3-toprJ1b. Among these clusters, the genetic construct of tmexC3.2D3-toprJ1b showed 2-fold higher minimum inhibitory concentration (MIC) of tigecycline than other three variants. In addition, it was found that the tmexCD-toprJ gene cluster was originated from Pseudomonas spp. and mainly located on Tn6855 variants inserted in the same umuC-like genes on chromosomes and plasmids. This unit co-localized with bla or bla on IncHI5-, Inc- and Inc-type plasmids in the five isolates of TMCR-GNB. The IncHI5- and Inc-type plasmids had the ability to conjugal transfer to E. coli J53 and P. aeruginosa PAO1, highlighting the potential risk of transfer of tmexCD-toprJ from Pseudomonas spp. to Enterobacterales. Importantly, genomic analysis showed that similar tmexCD-toprJ-harboring IncHI5 plasmids were also detected in human samples, suggesting transmission between environmental and human sectors. The emergence of TMCR-GNB from hospital sewage underscores the need for ongoing surveillance of antimicrobial resistance genes, particularly the novel resistance genes such as the tmexCD-toprJ gene clusters in the wastewater environment.
Topics: Humans; Carbapenems; Sewage; Tigecycline; Escherichia coli; Anti-Bacterial Agents; Gram-Negative Bacteria; Hospitals; Pseudomonas aeruginosa; Microbial Sensitivity Tests; beta-Lactamases
PubMed: 37480594
DOI: 10.1016/j.drup.2023.100989 -
Frontiers in Microbiology 2022A two-way relationship between diabetes and periodontitis has been discussed recently. Periodontitis microbiota might affect the immune homeostasis of diabetes, but the...
A two-way relationship between diabetes and periodontitis has been discussed recently. Periodontitis microbiota might affect the immune homeostasis of diabetes, but the molecular mechanism of their interactions is still not clear. The aims of this study were to clarify the possible immune regulatory effects of periodontitis microbiota on diabetes and the correlation between immunomodulation and ectopic colonization. A model of germ-free mice with streptozotocin-induced type 1 diabetes mellitus (T1D), which was orally inoculated with mixed saliva samples for 2 weeks, was used in this study. Those mice were randomly divided into two groups, namely, SP (where the T1D mice were orally inoculated with mixed saliva samples from periodontitis patients) and SH (where the T1D mice were orally inoculated with mixed saliva samples from healthy subjects). Ectopic colonization of saliva microbiota was assessed using culture-dependent method and Sanger sequencing, and the composition of gut microbiota was analyzed using 16S rRNA gene sequencing. Changes in 15 types of immune cells and six cytokines either from the small intestine or spleen were detected by multicolor flow cytometry. The correlation between gut microbiota and immune cells was evaluated by redundancy analysis. Although periodontitis microbiota minorly colonized the lungs, spleens, and blood system, they predominantly colonized the gut, which was mainly invaded by . SH and SP differed in beta diversity of the gut bacterial community. Compared to SH, microbial alteration in small intestine occurred with an increase of , , , , and a decrease of in SP. More types of immune cells were disordered in the spleen than in the small intestine by periodontitis microbiota, mainly with a dramatical increase in the proportion of macrophages, plasmacytoid dendritic cells (pDCs), monocytes, group 3 innate lymphoid cells, CD4-CD8- T cells and Th17 cells, as well as a decline of αβT cells in SP. Cytokines of IFNγ, IL17, and IL22 produced by CD4 + T cells as well as IL22 produced by ILCs of small intestine rose in numbers, and the intestinal and splenic pDCs were positively regulated by gut bacterial community in SP. In conclusion, periodontitis microbiota invasion leads to ectopic colonization of the extra-oral sites and immune cells infiltration, which might cause local or systemic inflammation. Those cells are considered to act as a "bridge" between T1D and periodontitis.
PubMed: 35756043
DOI: 10.3389/fmicb.2022.889415 -
Research in Microbiology 2021The order Enterobacterales was divided into seven families including the family Enterobacteriaceae in 2016. The genus Klebsiella within the family Enterobacteriaceae was...
The order Enterobacterales was divided into seven families including the family Enterobacteriaceae in 2016. The genus Klebsiella within the family Enterobacteriaceae was divided into two genera Klebsiella and Raoultella in 2001. Here, our phylogenomic analysis shows that the genus Raoultella is nested within the genus Klebsiella. Klebsiella and Raoultella together are monophyletic and share average amino acid identities (AAIs) of 86.9-89.6% above the AAI threshold (86%) for genus delimitation within the family Enterobacteriaceae. Klebsiella and Raoultella share AAIs of 79.9%-85.0% with the other genera within the subfamily "Klebsiella clade", which are in the range of inter-genus AAIs (74-85%) within the family Enterobacteriaceae. Klebsiella and Raoultella also share six known conserved signature indels. Therefore, we propose to reunify Klebsiella and Raoultella to the single genus Klebsiella and reclassify Raoultella electrica as Klebsiella electrica comb. nov. Our genome-based taxonomic analyses also identified seven potential novel species within the unified genus Klebsiella.
Topics: Amino Acid Sequence; Bacterial Proteins; Bacterial Typing Techniques; Enterobacteriaceae; Genes, rRNA; Genome, Bacterial; INDEL Mutation; Klebsiella; Klebsiella pneumoniae; Phenotype; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Terminology as Topic; Whole Genome Sequencing
PubMed: 34186167
DOI: 10.1016/j.resmic.2021.103851 -
Frontiers in Microbiology 2019Pyrethroids are broad-spectrum insecticides and presence of chiral carbon differentiates among various forms of pyrethroids. Microbial approaches have emerged as a... (Review)
Review
Pyrethroids are broad-spectrum insecticides and presence of chiral carbon differentiates among various forms of pyrethroids. Microbial approaches have emerged as a popular solution to counter pyrethroid toxicity to marine life and mammals. Bacterial and fungal strains can effectively degrade pyrethroids into non-toxic compounds. Different strains of bacteria and fungi such as spp., , sp., sp., sp., sp., sp., and spp., are used for the biodegradation of pyrethroids. Hydrolysis of ester bond by enzyme esterase/carboxyl esterase is the initial step in pyrethroid biodegradation. Esterase is found in bacteria, fungi, insect and mammalian liver microsome cells that indicates its hydrolysis ability in living cells. Biodegradation pattern and detected metabolites reveal microbial consumption of pyrethroids as carbon and nitrogen source. In this review, we aim to explore pyrethroid degrading strains, enzymes and metabolites produced by microbial strains. This review paper covers in-depth knowledge of pyrethroids and recommends possible solutions to minimize their environmental toxicity.
PubMed: 31428072
DOI: 10.3389/fmicb.2019.01778 -
International Journal of Environmental... May 2022Carbapenems are antibiotics of pivotal importance in human medicine, the efficacy of which is threatened by the increasing prevalence of carbapenem-resistant (CRE)....
Carbapenems are antibiotics of pivotal importance in human medicine, the efficacy of which is threatened by the increasing prevalence of carbapenem-resistant (CRE). Urban ponds may be reservoirs of CRE, although this hypothesis has been poorly explored. We assessed the proportion of CRE in urban ponds over a one-year period and retrieved 23 isolates. These were submitted to BOX-PCR, PFGE, 16S rDNA sequencing, antibiotic susceptibility tests, detection of carbapenemase-encoding genes, and conjugation assays. Isolates were affiliated with ( = 1), ( = 11), ( = 8), and ( = 3). Carbapenemase-encoding genes were detected in 21 isolates: ( = 20), ( = 6), and ( = 1), with 7 isolates carrying two carbapenemase genes. Clonal isolates were collected from different ponds and in different campaigns. F6, N9, and N10 were predicted as pathogens from whole-genome sequence analysis, which also revealed the presence of several resistance genes and mobile genetic elements. We found that was located on Tnb ( F6 and N10) or Tnd ( N9). The former was part of an IncFIA-FII pBK30683-like plasmid. In addition, was in a class 3 integron, either chromosomal ( N9) or plasmidic ( N10). Our findings confirmed the role of urban ponds as reservoirs and dispersal sites for CRE.
Topics: Carbapenems; Enterobacteriaceae Infections; Humans; Klebsiella; Microbial Sensitivity Tests; Ponds
PubMed: 35627386
DOI: 10.3390/ijerph19105848 -
European Journal of Case Reports in... 2021is a bacterium that belongs to the Enterobacteriaceae family. The most frequently reported infections are gastrointestinal and hepatobiliary. Urinary tract infections...
UNLABELLED
is a bacterium that belongs to the Enterobacteriaceae family. The most frequently reported infections are gastrointestinal and hepatobiliary. Urinary tract infections are very rarely reported and bloodstream infections are usually reported without an identified source. This bacterium is responsible for an increasing number of infections, especially in immunocompromised patients. The authors describe the first case ever reported of an immunocompromised patient due to non-Hodgkin lymphoma MALT type and corticotherapy, who developed urinary tract infection and subsequently bacteriemia due to this pathogen.
LEARNING POINTS
is a virulent pathogen causing community-acquired and hospital-acquired infection, especially in immunocompromised populations.Although most cases of infection are susceptible to standard antibiotic regimens, multi-drug resistant strains have been reported, which may pose a severe risk to the immunocompromised patient.Physicians should be aware that some treatments may increase immunosuppression, thus enabling infection by opportunistic agents such as .
PubMed: 34912750
DOI: 10.12890/2021_003023 -
Scientific Reports Mar 2022Raoultella planticola is an emerging pathogen causing several infections in humans, and its roles in the propagation of antibiotic resistance genes (ARGs) remain...
Raoultella planticola is an emerging pathogen causing several infections in humans, and its roles in the propagation of antibiotic resistance genes (ARGs) remain uncharacterized. In this study, a carbapenem and tigecycline-resistant R. planticola isolate was recovered from hospital sewage. It carried nine plasmids, bearing 30 ARGs, including one bla and two bla. It also contained a plasmid-borne efflux pump gene cluster, tmexCD1-toprJ, conferring resistance to tigecycline. Analysis of plasmid sequences revealed that both bla-carrying plasmids were highly similar to those recovered from humans, reinforcing the close relatedness of environmental and clinical isolates. We also identified that plasmid bearing bla or tmexCD1-toprJ1 was transferable, and can be stabilized in the host bacteria, indicating that the R. planticola isolate has a considerable potential in the dissemination of ARGs. Besides, we found that this isolate could produce biofilm and was virulent in a Galleria mellonella infection model. In conclusion, our study shows the convergence of virulence and multidrug resistance in a R. planticola isolate. This potentially virulent superbug may disseminate into its receiving rivers, and finally to humans through cross-contamination during recreation activities or daily use of water, which poses a risk to public health.
Topics: Anti-Bacterial Agents; Carbapenems; Enterobacteriaceae; Humans; Klebsiella pneumoniae; Microbial Sensitivity Tests; Plasmids; Tigecycline; Virulence; beta-Lactamases
PubMed: 35264602
DOI: 10.1038/s41598-022-07778-0 -
PloS One 2023To study antimicrobial resistance and virulence genes of Klebsiella pneumoniae and Raoultella strains isolated from captive giant pandas. Non-duplicate fecal samples...
To study antimicrobial resistance and virulence genes of Klebsiella pneumoniae and Raoultella strains isolated from captive giant pandas. Non-duplicate fecal samples were collected from 128 giant pandas during 2017-2019. All isolated microbial strains were tested for antimicrobial drug susceptibility using BD verification panels. Four extended-spectrum β-lactamase resistance genes, nine virulence genes and six capsular serotype genes were detected using PCR. 42 K. pneumoniae and nine Raoultella strains were isolated from different giant pandas. Antibiotic resistance rates were 1.9%-23.5%, except for ampicillin, and 7.8% of the isolates were multidrug-resistant to 7-10 antibiotic classes. This is the first time that a multidrug-resistant R. ornithinolytica strain has been isolated from captive giant pandas. The blaTEM, blaCTX-M, blaSHV and blaDHA genes were detected in four MDR ESBL- K. pneumoniae strains. The rmpA, iutA, ybtS, iroN and iroB genes were positively detected in 11.7% of the isolates. Capsular serotype (K2, K5, K54 and K57) genes were all detected in four K. pneumoniae strains, and one was identified as hypervirulent. This study showed that MDR ESBL- K. pneumoniae, hypervirulent K. pneumoniae, MDR R. ornithinolytica and the colistin-resistant strain may pose risks to captive giant pandas and their keepers, and that the diversity of antibiotic resistance and virulence genes in Klebsiella and Raoultella should be monitored regularly.
Topics: Animals; Anti-Bacterial Agents; Virulence; Klebsiella pneumoniae; Ursidae; Drug Resistance, Bacterial; Prevalence; Klebsiella Infections; beta-Lactamases; Microbial Sensitivity Tests
PubMed: 36996135
DOI: 10.1371/journal.pone.0283738