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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 Cellular and Infection... 2024spp. is a genus of bacteria that is known to be closely related to . It has been debated whether should be reclassified as a subgroup of . The aim of this study is to... (Comparative Study)
Comparative Study
PURPOSE
spp. is a genus of bacteria that is known to be closely related to . It has been debated whether should be reclassified as a subgroup of . The aim of this study is to compare clinical aspects of and , a species of that is known to be bacteriologically similar to spp.
METHODS
Using data collected at a tertiary care hospital in the United States, we identified 43 patients with infection and 1173 patients with infection. We compared patient demographics (age and sex), hospitalization status, isolation sites and antibiotic resistance profiles between the two species.
RESULTS
There was no significant difference in patient demographics between the two bacteria species. The proportions of intensive care unit (ICU) admission were higher among patients with infection (p=0.008). The most common site of isolation was urine for both species (39.5% of all patients with spp. vs. 59.3% for ). The second most common site of isolation was blood stream for spp. (23.3%) and respiratory tract for (10.8%). Except for the high proportion of resistant isolates of spp. for Trimethoprim/sulfamethoxazole, the antibiotic susceptibility profiles were similar between the two bacteria species. Both were susceptible to ciprofloxacin and meropenem.
CONCLUSION
While there are no significant differences in the patient demographics and antibiotic susceptibility profiles between spp. and , may cause more serious infection requiring ICU admissions. Also, may cause blood stream infection more frequently than .
Topics: Humans; Male; Klebsiella oxytoca; Female; Middle Aged; Aged; Enterobacteriaceae; Klebsiella Infections; Anti-Bacterial Agents; Enterobacteriaceae Infections; Microbial Sensitivity Tests; Adult; Tertiary Care Centers; Intensive Care Units; United States; Aged, 80 and over; Drug Resistance, Bacterial
PubMed: 38887491
DOI: 10.3389/fcimb.2024.1260212 -
Antimicrobial Resistance and Infection... Jun 2022Sepsis due to multidrug resistant (MDR) bacteria is a growing public health problem mainly in low-income countries.
BACKGROUND
Sepsis due to multidrug resistant (MDR) bacteria is a growing public health problem mainly in low-income countries.
METHODS
A multicenter study was conducted between October 2019 and September 2020 at four hospitals located in central (Tikur Anbessa and Yekatit 12), southern (Hawassa) and northern (Dessie) parts of Ethiopia. A total of 1416 patients clinically investigated for sepsis were enrolled. The number of patients from Tikur Anbessa, Yekatit 12, Dessie and Hawassa hospital was 501, 298, 301 and 316, respectively. At each study site, blood culture was performed from all patients and positive cultures were characterized by their colony characteristics, gram stain and conventional biochemical tests. Each bacterial species was confirmed using Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI TOF). Antimicrobial resistance pattern of bacteria was determined by disc diffusion. Logistic regression analysis was used to assess associations of dependent and independent variables. A p-value < 0.05 was considered as statistically significant. The data was analyzed using SPSS version 25.
RESULTS
Among 1416 blood cultures performed, 40.6% yielded growth. Among these, 27.2%, 0.3% and 13.1%, were positive for pathogenic bacteria, yeast cells and possible contaminants respectively. Klebsiella pneumoniae (26.1%), Klebsiella variicola (18.1%) and E. coli (12.4%) were the most frequent. Most K. variicola were detected at Dessie (61%) and Hawassa (36.4%). Almost all Pantoea dispersa (95.2%) were isolated at Dessie. Rare isolates (0.5% or 0.2% each) included Leclercia adecarboxylata, Raoultella ornithinolytica, Stenotrophomonas maltophilia, Achromobacter xylosoxidans, Burkholderia cepacia, Kosakonia cowanii and Lelliottia amnigena. Enterobacteriaceae most often showed resistance to ampicillin (96.2%), ceftriaxone (78.3%), cefotaxime (78%), cefuroxime (78%) and ceftazidime (76.4%). MDR frequency of Enterobacteriaceae at Hawassa, Tikur Anbessa, Yekatit 12 and Dessie hospital was 95.1%, 93.2%, 87.3% and 67.7%, respectively. Carbapenem resistance was detected in 17.1% of K. pneumoniae (n = 111), 27.7% of E. cloacae (n = 22) and 58.8% of Acinetobacter baumannii (n = 34).
CONCLUSION
Diverse and emerging gram-negative bacterial etiologies of sepsis were identified. High multidrug resistance frequency was detected. Both on sepsis etiology types and MDR frequencies, substantial variation between hospitals was determined. Strategies to control MDR should be adapted to specific hospitals. Standard bacteriological services capable of monitoring emerging drug-resistant sepsis etiologies are essential for effective antimicrobial stewardship.
Topics: Anti-Bacterial Agents; Drug Resistance, Bacterial; Escherichia coli; Ethiopia; Hospitals; Humans; Klebsiella pneumoniae; Microbial Sensitivity Tests; Referral and Consultation; Sepsis
PubMed: 35698179
DOI: 10.1186/s13756-022-01122-x -
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 -
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 -
Applied and Environmental Microbiology Oct 2023While the evolution of antimicrobial resistance is well studied in free-living bacteria, information on resistance development in dense and diverse biofilm communities...
While the evolution of antimicrobial resistance is well studied in free-living bacteria, information on resistance development in dense and diverse biofilm communities is largely lacking. Therefore, we explored how the social interactions in a duo-species biofilm composed of the brewery isolates and influence the adaptation to the broad-spectrum antimicrobial sulfathiazole. Previously, we showed that the competition between these brewery isolates enhances the antimicrobial tolerance of . Here, we found that this enhanced tolerance in duo-species biofilms is associated with a strongly increased antimicrobial resistance development in . Whereas was not able to evolve resistance against sulfathiazole in monospecies conditions, it rapidly evolved resistance in the majority of the duo-species communities. Although the initial presence of was thus required for to acquire resistance, the resistance mechanisms did not depend on the presence of . Whole genome sequencing of resistant clones showed no clear mutational hot spots. This indicates that the acquired resistance phenotype depends on complex interactions between low-frequency mutations in the genetic background of the strains. We hypothesize that the increased tolerance in duo-species conditions promotes resistance by enhancing the selection of partially resistant mutants and opening up novel evolutionary trajectories that enable such genetic interactions. This hypothesis is reinforced by experimentally excluding potential effects of increased initial population size, enhanced mutation rate, and horizontal gene transfer. Altogether, our observations suggest that the community mode of life and the social interactions therein strongly affect the accessible evolutionary pathways toward antimicrobial resistance.IMPORTANCEAntimicrobial resistance is one of the most studied bacterial properties due to its enormous clinical and industrial relevance; however, most research focuses on resistance development of a single species in isolation. In the present study, we showed that resistance evolution of brewery isolates can differ greatly between single- and mixed-species conditions. Specifically, we observed that the development of antimicrobial resistance in certain species can be significantly enhanced in co-culture as compared to the single-species conditions. Overall, the current study emphasizes the need of considering the within bacterial interactions in microbial communities when evaluating antimicrobial treatments and resistance evolution.
Topics: Anti-Infective Agents; Biofilms; Bacteria; Phenotype; Sulfathiazoles; Anti-Bacterial Agents
PubMed: 37819078
DOI: 10.1128/aem.01155-23 -
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 -
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