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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 -
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 -
Annals of Clinical Microbiology and... Nov 2023Globally, surgical site infections (SSI) are the most commonly reported healthcare-associated infections.
BACKGROUND
Globally, surgical site infections (SSI) are the most commonly reported healthcare-associated infections.
METHODS
A multicentre study was conducted among patients who underwent surgical procedures at four hospitals located in Northern (Debre Tabor), Southern (Hawassa), Southwest (Jimma), and Central (Tikur Anbessa) parts of Ethiopia. A total of 752 patients clinically studied for surgical site infection were enrolled. The number of patients from Debre Tabor, Hawassa, Jimma, and Tikur Anbessa, hospitals was 172, 184, 193, and 203, respectively. At each study site, SSI discharge culture was performed from all patients, and positive cultures were characterized by 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). An antimicrobial susceptibility test (AST) was done on Mueller-Hinton agar using the disk diffusion method. Logistic regression analysis was used to assess associations of dependent and independent variables. A p-value < 0.05 was considered statistically significant. Data were analysed using STATA 16 software.
RESULTS
Among 752 wound discharge cultures performed, 65.5% yielded growth. Among these, 57.9% and 42.1% were Gram-negative and Gram-positive isolates, respectively. In this study, a total of 494 bacteria were isolated; Staphylococcus aureus (31%), Escherichia coli (20.7%), and Klebsiella pneumoniae (9.8%) were the most common. Rare isolates (0.8% each) included Raoultella ornithinolytica, Stenotrophomonas maltophilia, Alcalignes faecalis, Pantoea ecurina, Bacillus flexus, and Paenibacillus tylopili. Enterobacteriaceae showed high levels of resistance to most of the tested antibiotics but lower levels of ertapenem (32.9%), amikacin (24.3%), imipenem (20.3%), and meropenem (17.6%) resistance. Multidrug-resistant (MDR) frequency of Enterobacteriaceae at Debre Tabor, Hawassa, Jimma, and Tikur Anbessa hospitals was 84.5%, 96.5%, 97.3%, and 94%, respectively. Ages ≥ 61 years (AOR = 2.83, 95% CI: 1.02-7.99; P 0.046), prolonged duration of hospital stay (AOR = 4.15, 95% CI: 2.87-6.01; P 0.000), history of previous antibiotics use (AOR = 2.83, 95% CI: 1.06-2.80; P 0.028), history of smoking (AOR = 2.35, 95% CI: 1.44-3.83; P 0.001), emergency surgery (AOR = 2.65, 95% CI: 1.92-3.66; P 0.000), and duration of operation (AOR = 0.27, 95% CI: 0.181-0.392; P 0.000) were significant risk factors.
CONCLUSION
The most prevalent isolates from Gram-positive and Gram-negative bacteria across all hospitals were S. aureus and E. coli, respectively. Many newly emerging Gram-negative and Gram-positive bacteria were identified. Variation between hospitals was found for both SSI etiology type and MDR frequencies. Hence, to prevent the emergence and spread of MDR bacteria, standard bacteriological tests and their AST are indispensable for effective antimicrobial stewardship.
Topics: Humans; Anti-Bacterial Agents; Surgical Wound Infection; Cross-Sectional Studies; Staphylococcus aureus; Escherichia coli; Ethiopia; Prospective Studies; Gram-Negative Bacteria; Gram-Positive Bacteria; Drug Resistance, Bacterial; Microbial Sensitivity Tests; Bacteria; Drug Resistance, Multiple, Bacterial
PubMed: 37936207
DOI: 10.1186/s12941-023-00643-6 -
Antibiotics (Basel, Switzerland) Jun 2023Mobile colistin resistance () genes (-1 to -10) are plasmid-encoded genes that threaten the clinical utility of colistin (COL), one of the highest-priority critically... (Review)
Review
Mobile Colistin Resistance () Gene-Containing Organisms in Poultry Sector in Low- and Middle-Income Countries: Epidemiology, Characteristics, and One Health Control Strategies.
Mobile colistin resistance () genes (-1 to -10) are plasmid-encoded genes that threaten the clinical utility of colistin (COL), one of the highest-priority critically important antibiotics (HP-CIAs) used to treat infections caused by multidrug-resistant and extensively drug-resistant bacteria in humans and animals. For more than six decades, COL has been used largely unregulated in the poultry sector in low- and middle-income countries (LMICs), and this has led to the development/spread of gene-containing bacteria (MGCB). The prevalence rates of -positive organisms from the poultry sector in LMICs between January 1970 and May 2023 range between 0.51% and 58.8%. Through horizontal gene transfer, conjugative plasmids possessing insertion sequences (ISs) (especially IS), transposons (predominantly Tn), and integrons have enhanced the spread of -1, -2, -3, -4, -5, -7, -8, -9, and -10 in the poultry sector in LMICs. These genes are harboured by , , , , , , , , , , , , and species, belonging to diverse clones. The -1, -3, and -10 genes have also been integrated into the chromosomes of these bacteria and are mobilizable by ISs and integrative conjugative elements. These bacteria often coexpress with virulence genes and other genes conferring resistance to HP-CIAs, such as extended-spectrum cephalosporins, carbapenems, fosfomycin, fluoroquinolone, and tigecycline. The transmission routes and dynamics of MGCB from the poultry sector in LMICs within the One Health triad include contact with poultry birds, feed/drinking water, manure, poultry farmers and their farm workwear, farming equipment, the consumption and sale of contaminated poultry meat/egg and associated products, etc. The use of pre/probiotics and other non-antimicrobial alternatives in the raising of birds, the judicious use of non-critically important antibiotics for therapy, the banning of nontherapeutic COL use, improved vaccination, biosecurity, hand hygiene and sanitization, the development of rapid diagnostic test kits, and the intensified surveillance of genes, among others, could effectively control the spread of MGCB from the poultry sector in LMICs.
PubMed: 37508213
DOI: 10.3390/antibiotics12071117 -
Frontiers in Microbiology 2023Rapid industrialization and urbanization have led to widespread metal contamination in aquatic ecosystems. This study explores the metal tolerance and biosorption...
Rapid industrialization and urbanization have led to widespread metal contamination in aquatic ecosystems. This study explores the metal tolerance and biosorption characteristics of four bacterial strains ( sp. L2, sp. L30, sp. R3, and sp. R19) isolated from Saint Clair River sediments. These strains effectively removed various metal cations (As, Pb, Cu, Mn, Zn, Cd, Cr, and Ni) in single and multi-metal solutions. Minimum inhibitory concentration (MIC) assays revealed strain-specific variations in metal tolerance, with L2 and L30 exhibiting higher tolerance. Surprisingly, R3 and R19, despite lower tolerance, demonstrated superior metal removal efficiency, challenging the notion that tolerance dictates removal efficacy. In single-metal solutions, R3 and R19 excelled at extracting various metal ions, while competitive binding in multi-metal solutions hindered removal. However, R3 and R19 retained higher removal efficiencies, possibly due to enhanced flocculation activities facilitating metal-ion contact. Comprehensive Fourier-transform infrared (FTIR) analysis highlighted the strains' metal-binding capabilities, with novel peaks emerging after metal exposure, indicative of extracellular polymeric substance (EPS) production. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed metal accumulation on bacterial surfaces and within cytoplasmic regions and revealed morphological changes and metal adsorption patterns, emphasizing the strains' ability to adapt to metal stress. Scanning transmission microscopy (STEM) and EDX analysis uncovered metal accumulation within bacterial cells, underscoring the complexity of microbial-metal interactions. This study also confirms that the simultaneous presence of an aqueous solution may cause a mutual inhibition in the adsorption of each metal to the EPS resulting in reduced metal uptake, which emphasizes the need to select specific bacterial strains for a given metal-containing effluent. The differences in metal distribution patterns between sp. R19 and sp. L30 suggest species-specific metal accumulation strategies driven by environmental conditions and metal availability. The heavy metal-removing capabilities and the ability to grow over a wide range of metal concentrations of the strains used in this study may offer an advantage to employ these organisms for metal remediation in bioreactors or .
PubMed: 37942073
DOI: 10.3389/fmicb.2023.1278886 -
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 -
Ecotoxicology and Environmental Safety Sep 2023Polyolefin plastics, such as polyethylene (PE) and polystyrene (PS), are the most widely used synthetic plastics in our daily life. However, the chemical structure of...
Polyolefin plastics, such as polyethylene (PE) and polystyrene (PS), are the most widely used synthetic plastics in our daily life. However, the chemical structure of polyolefin plastics is composed of carbon-carbon (C-C) bonds, which is extremely stable and makes polyolefin plastics recalcitrant to degradation. The growing accumulation of plastic waste has caused serious environmental pollution and has become a global environmental concern. In this study, we isolated a unique Raoultella sp. DY2415 strain from petroleum-contaminated soil that can degrade PE and PS film. After 60 d of incubation with strain DY2415, the weight of the UV-irradiated PE (UVPE) film and PS film decreased by 8% and 2%, respectively. Apparent microbial colonization and holes on the surface of the films were observed by scanning electron microscopy (SEM). Furthermore, the Fourier transform infrared spectrometer (FTIR) results showed that new oxygen-containing functional groups such as -OH and -CO were introduced into the polyolefin molecular structure. Potential enzymes that may be involved in the biodegradation of polyolefin plastics were analyzed. These results demonstrate that Raoultella sp. DY2415 has the ability to degrade polyolefin plastics and provide a basis for further investigating the biodegradation mechanism.
Topics: Polystyrenes; Polyethylene; Petroleum; Soil; Enterobacteriaceae; Biodegradation, Environmental; Carbon; Plastics
PubMed: 37429089
DOI: 10.1016/j.ecoenv.2023.115232 -
Cureus Oct 2023We present a case of () infection that resulted in community-acquired pneumonia in an immunocompetent patient with an eight-week history of productive cough. This...
We present a case of () infection that resulted in community-acquired pneumonia in an immunocompetent patient with an eight-week history of productive cough. This gram-negative bacterium is typically found in the environment and has the potential to infect humans. infections in humans have been recorded in several case reports from throughout the world in recent years, usually affecting immunocompromised patients. Although is sensitive to most antibiotic groups, recent studies have revealed an increase in the infrequent acquisition of resistance genes in , such as carbapenem resistance, making this pathogen a potential emergent threat. Our patient acquired pneumonia in the absence of any underlying risk factors, making this the first case in the UK of causing community-acquired pneumonia in an immunocompetent person.
PubMed: 38021927
DOI: 10.7759/cureus.47188 -
Cureus Mar 2024The case presentation discusses the clinical evaluation and treatment of a two-year-old female exhibiting symptoms such as dysuria, constipation, and foul-smelling...
The case presentation discusses the clinical evaluation and treatment of a two-year-old female exhibiting symptoms such as dysuria, constipation, and foul-smelling urine. Upon evaluation, the patient was found to be co-infected with Raoultella planticola and Escherichia coli. This co-infection poses unique challenges in diagnosis and treatment, as both pathogens may contribute to the manifestation of symptoms. The initial diagnosis of Raoultella planticola is notable, given its relatively rare occurrence and the potential for misdiagnosis. This case study contributes to our understanding of diagnosing and distinguishing symptoms at various stages of the illness, particularly in cases of co-infection. Following an initial urinalysis and urine culture confirming the presence of both pathogens, a 10-day course of antibiotics was prescribed. Subsequent examinations at Rady Children's Hospital-San Diego included kidney and abdomen imaging to rule out underlying issues. The co-infection underscores the importance of thorough diagnostic procedures and tailored treatment approaches. Additionally, it highlights the need for heightened awareness among healthcare providers regarding emerging pathogens and their potential clinical implications.
PubMed: 38686243
DOI: 10.7759/cureus.57262 -
Biofilm Dec 2023Many companies in the food industry apply reverse osmosis (RO) membranes to ensure high-quality reuse of water. Biofouling is however, a common, recalcitrant and...
Many companies in the food industry apply reverse osmosis (RO) membranes to ensure high-quality reuse of water. Biofouling is however, a common, recalcitrant and recurring problem that blocks transport over membranes and decreases the water recovery. Microorganisms adhering to membranes may form biofilm and produce an extracellular matrix, which protects against external stress and ensures continuous attachment. Thus, various agents are tested for their ability to degrade and disperse biofilms. Here, we identified industrially relevant bacterial model communities that form biofilms on RO membranes used for treating process water before reuse. There was a marked difference in the biofilm forming capabilities of bacteria isolated from contaminated RO membranes. One species, , was particularly capable of forming biofilm and was included in most communities. The potential of different enzymes (Trypsin-EDTA, Proteinase K, α-Amylase, β-Mannosidase and Alginate lyase) as biofouling dispersing agents was evaluated at different concentrations (0.05 U/ml and 1.28 U/ml). Among the tested enzymes, β-Mannosidase was the only enzyme able to reduce biofilm formation significantly within 4 h of exposure at 25 °C (0.284 log reduction), and only at the high concentration. Longer exposure duration, however, resulted in significant biofilm reduction by all enzymes tested (0.459-0.717 log reduction) at both low and high concentrations. Using confocal laser scanning microscopy, we quantified the biovolume on RO membranes after treatment with two different enzyme mixtures. The application of proteinase K and β-Mannosidase significantly reduced the amount of attached biomass (43% reduction), and the combination of all five enzymes showed even stronger reducing effect (71% reduction). Overall, this study demonstrates a potential treatment strategy, using matrix-degrading enzymes for biofouled RO membranes in food processing water treatment streams. Future studies on optimization of buffer systems, temperature and other factors could facilitate cleaning operations based on enzymatic treatment extending the lifespan of membranes with a continuous flux.
PubMed: 37131492
DOI: 10.1016/j.bioflm.2023.100119