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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 -
Frontiers in Microbiology 2022Associated microbes of several herbivorous insects can improve insect fitness. However, the contribution of specific insect gut bacterium to plant toxin toxification for...
Associated microbes of several herbivorous insects can improve insect fitness. However, the contribution of specific insect gut bacterium to plant toxin toxification for its host fitness remains scarce. Here, a gut bacterium from the ghost moth larvae was identified. This bacterium grew unhindered in the presence of , which is a natural food for ghost moth larvae but showed significant growth inhibition and toxicity against . reared on artificial diets containing 5, 15 and 25% powder after 7 days coculture with were found to have shorter larval and pupal durations than on the diets containing powder but without coculture. HPLC analysis revealed that the content of quercetin in mineral medium containing 15% powder after 7 days coculture with was significantly decreased (79.48%) as compared with that in powder without coculture. fermentation further verified that could degrade 85.56% quercetin in Lucia-Bertani medium. reared on artificial diets containing 0.01, 0.05 and 0.1 mg/g quercetin after 48 h coculture with were also found to have shorter larval, prepupal and pupal durations, as well as higher average pupal weight and adult emergence rate than on the diets containing quercetin, but without coculture. In addition, was detected in the bud and root tissues of the sterilized , indicating that larvae might acquire this bacterium through feeding. These results demonstrate that the gut bacteria contribute to the degradation of plant toxic molecules to improve the development of herbivorous insects and provide fundamental knowledge for developing effective methods for beneficial insect rearing and pest control.
PubMed: 36620066
DOI: 10.3389/fmicb.2022.1079550 -
IDCases 2019There is paucity of literature available on infection. Microbiological identification of is difficult and isolates are frequently misidentified as Klebsiella This...
BACKGROUND AND OBJECTIVES
There is paucity of literature available on infection. Microbiological identification of is difficult and isolates are frequently misidentified as Klebsiella This series of 3 cases septicemia provides a description of the pitfalls and challenges in the diagnosis and management of the highly resistant strains isolated and to the best of our knowledge, is the first report from Pakistan.
METHODS
The medical records of 3 cases reported in the hospital over two months were reviewed retrospectively to record all relevant clinical information. Organism was identified by using Analytical profile index (API) 20 E with 90-95% successful identification and the sensitivity testing was performed by disc diffusion method.
RESULTS
This organism caused fulminant sepsis in case 2 resulting in mortality and complicated urinary tract infection in the third, while in case 1 it preceded the fatal candidemia. All three patients were females who had multiple co-morbid and had a history of protracted hospital stay and antibiotic usage elsewhere before being shifted to our hospital. The isolates were resistant to all beta lactams and were even colistin resistant in two patients, creating challenges and suboptimal response for effective antibiotic therapy.
CONCLUSIONS
The purpose of this case series is to highlight the highly drug resistant profile of this organism and the fulminant infection it can cause, which if spreads in our hospitals due to breaches in infection control practices, can pose risk as a deadly and untreatable nosocomial infection.
PubMed: 31485415
DOI: 10.1016/j.idcr.2019.e00628 -
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 -
Cureus Oct 2020Introduction Universally, blood stream infections are linked with increasing morbidity and mortality. Timely diagnosis for identification of bacterial etiology, their...
Introduction Universally, blood stream infections are linked with increasing morbidity and mortality. Timely diagnosis for identification of bacterial etiology, their susceptibility pattern and choice of empiric treatment plays a vital role in management. Objective To reveal the etiological profile and antibiotic sensitivity in blood culture specimens in a tertiary care setting. Methods This descriptive study was carried out in pathology laboratory of a tertiary care hospital from August 2016 to July 2019. All the 750 blood culture bottles were processed and isolates were recognized by morphological appearance on recommended media, gram stain, and different biochemical tests using Analytic Profile Index. Antibiotic sensitivity was implemented by modified disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) principles (2019). Results Out of 750 blood samples, 212 (28.26%) were culture positive. The percentage of gram-negative bacilli (n = 105) and gram-positive cocci (n = 104) was almost same (49.52%), while candida spp. was recovered from three (1.41%) isolates. The identified gram-negative bacteria were E. coli and Acinetobacter baumannii each (19.04%), Klebsiella pneumoniae and Pseudomonas aeruginosa each (16.19%), Enterobacter cloaca (11.42%), Salmonella typhi (8.57%), Burkholderia cepacia (1.90%), and Raoultella terrigena (7.61%). Among gram-positive isolates, coagulase-negative staphylococci (79.80%), Staphylococcus aureus (6.73%), Enterococcus spp. (11.53%) and Streptococcus spp. (1.92%) were recovered. Colistin, imipenem, meropenem, and amikacin were most successful against gram-negative rods. The sensitivity to vancomycin, teicoplanin and linezolid was 100%, for gram positive organisms. Methicillin resistance was present in 84.4% Staphylococcal isolates. Conclusion Local data showing changing etiological pattern and antibiogram of isolated pathogens, along with adequate infection prevention and control measures can be useful to improve patient care, in terms of hospital stay, duration of medication and treatment cost.
PubMed: 33209556
DOI: 10.7759/cureus.11000 -
Microbiology Resource Announcements Jul 2019is a bacterial species associated with soil and aquatic environments; however, sporadic cases of opportunistic disease in humans have been reported. Here, we report the...
is a bacterial species associated with soil and aquatic environments; however, sporadic cases of opportunistic disease in humans have been reported. Here, we report the first two complete genome sequences from clinical strains isolated from human sources that have been deposited in the National Collection of Type Cultures (NCTC).
PubMed: 31270187
DOI: 10.1128/MRA.00239-19 -
Molecular Microbiology Jul 2021Guanidine is sensed by at least four different classes of riboswitches that are widespread in bacteria. However, only very few insights into physiological roles of...
Guanidine is sensed by at least four different classes of riboswitches that are widespread in bacteria. However, only very few insights into physiological roles of guanidine exist. Genes predominantly regulated by guanidine riboswitches are Gdx transporters exporting the compound from the bacterial cell. In addition, urea/guanidine carboxylases and associated hydrolases and ABC transporters are often found combined in guanidine-inducible operons. We noted that the associated ABC transporters are configured to function as importers, challenging the current view that riboswitches solely control the detoxification of guanidine in bacteria. We demonstrate that the carboxylase pathway enables utilization of guanidine as sole nitrogen source. We isolated three enterobacteria (Raoultella terrigena, Klebsiella michiganensis, and Erwinia rhapontici) that utilize guanidine efficiently as N-source. Proteome analyses show that the expression of a carboxylase, associated hydrolases and transport genes is strongly induced by guanidine. Finding two urea/guanidine carboxylase enzymes in E. rhapontici, we demonstrate that the riboswitch-controlled carboxylase displays specificity toward guanidine, whereas the other enzyme prefers urea. We characterize the distribution of riboswitch-associated carboxylases and Gdx exporters in bacterial habitats by analyzing available metagenome data. The findings represent a paradigm shift from riboswitch-controlled detoxification of guanidine to the uptake and assimilation of this enigmatic nitrogen-rich compound.
Topics: Carbon-Nitrogen Ligases; Energy Metabolism; Enterobacteriaceae; Erwinia; Gene Expression Regulation, Bacterial; Guanidine; Hydrolases; Klebsiella; Membrane Transport Proteins; Riboswitch
PubMed: 33590553
DOI: 10.1111/mmi.14702 -
Frontiers in Microbiology 2021Endophytic nitrogen-fixing (diazotrophic) bacteria are essential members of the microbiome of switchgrass (), considered to be an important commodity crop in bioenergy...
Endophytic nitrogen-fixing (diazotrophic) bacteria are essential members of the microbiome of switchgrass (), considered to be an important commodity crop in bioenergy production. While endophytic diazotrophs are known to provide fixed atmospheric nitrogen to their host plant, there are many other plant growth-promoting (PGP) capabilities of these organisms to be demonstrated. The diversity of PGP traits across different taxa of switchgrass-colonizing endophytes is understudied, yet critical for understanding endophytic function and improving cultivation methods of important commodity crops. Here, we present the isolation and characterization of three diazotrophic endophytes: R1C, F10Cl, and R1Gly. Strains R1C and F10Cl were isolated from switchgrass and strain R1Gly, while isolated from tobacco, is demonstrated herein to colonize switchgrass. Each strain exhibited highly diverse genomic and phenotypic PGP capabilities. Strain F10Cl and R1Gly demonstrated the highest functional similarity, suggesting that, while endophyte community structure may vary widely based on host species, differences in functional diversity are not a clearly delineated. The results of this study advance our understanding of diazotrophic endophyte diversity, which will allow us to design robust strategies to improve cultivation methods of many economically important commodity crops.
PubMed: 34867848
DOI: 10.3389/fmicb.2021.730440 -
Archivos Espanoles de Urologia Apr 2021Emerging urinary infections by rare germs are a public health problem. The objectives of this article are to review urinary tract infections caused by an emerging... (Review)
Review
OBJECTIVES
Emerging urinary infections by rare germs are a public health problem. The objectives of this article are to review urinary tract infections caused by an emerging genus of bacteria called Raoultella and to report a case of asymptomatic urinary tract infection by Raoultella ornithinolytica.
MATERIALS AND METHODS
A review of publications on urinary tract infections caused by the genus Raoultella between 2009 and 2018 is carried out and a case of asymptomatic urinary tract infection by Raoultella ornithinolytica is reported. The search of articles in Medline/ Pubmed and Google was performed with the keywords: Raoultella, Raoultella ornithinolytica, urinary tract infection. Twelve variables were studied: year of publication, authors, specialty, type of infection, number of cases, sex, age, immunosuppression, oncological patient, urological instrumentation, urological surgery and neurogenic bladder. Results were analyzed using descriptive statistics. A new case is described.
RESULTS
24 publications were found with 120 cases of urinary infections of the genus Raoultella between 2009 and 2018, corresponding to Raoultella ornithinolytica 40.8%, Raoultella planticola 28.3%, Raoultella terrigena 30.8% and Raoultella electrica 0%. The series included 43 men (35.8%), 53 women (44.1%) and 24 patients with this data not provided (20%). The minimum age was 14 days, the maximum was 97 years and the average age was 56.6. The types of infection detected were: uncomplicated UTI 94.1%, UTI in newborn 1.6%, acute prostatitis 0.8%, chronic prostatitis 0.8%, giant kidney cyst infection 0.8%, calculous pyelonephritis 0.8% and recurrent cystitis 0.8%.
CONCLUSIONS
Urinary tract infections by species of the genus Raoultella occur in immunocompromised, oncological, instrumented or basic urological patients. The species Raoultella ornithinolytica described in 2011 is an emerging germ in urinary infections. This contribution is the second Spanish publication and twelfth worldwide of urinary infection by Raoultella ornithinolytica.
Topics: Aged, 80 and over; Anti-Bacterial Agents; Enterobacteriaceae; Enterobacteriaceae Infections; Female; Humans; Infant, Newborn; Male; Middle Aged; Urinary Tract Infections
PubMed: 33818423
DOI: No ID Found -
Frontiers in Microbiology 2024Seventeen Gram-negative, facultatively anaerobic bacterial strains were isolated from bleeding cankers of various broadleaf hosts and oak rhizosphere soil in Great...
Seventeen Gram-negative, facultatively anaerobic bacterial strains were isolated from bleeding cankers of various broadleaf hosts and oak rhizosphere soil in Great Britain. The strains were tentatively identified as belonging to the genus based on 16S rRNA gene sequencing. Multilocus sequence analysis (MLSA), based on four protein-encoding genes (, , , and ), separated the strains into three clusters within the genus clade. The majority of strains clustered with the type strain of , with the remaining strains divided into two clusters with no known type strain. Whole genome sequencing comparisons confirmed these two clusters of strains as belonging to two novel species which can be differentiated phenotypically from their current closest phylogenetic relatives. Therefore, two novel species are proposed: sp. nov. (type strain = BAC 10a-01-01 = LMG 33072 = CCUG 77096) and sp. nov. (type strain = TW_WC1a.1 = LMG 33073 = CCUG 77094).
PubMed: 38756725
DOI: 10.3389/fmicb.2024.1386923