-
Environmental Analysis, Health and... Dec 2023The indiscriminate deposition of metal-containing substances into the environment contributes significantly to high concentrations of metals in the soil resulting in...
The indiscriminate deposition of metal-containing substances into the environment contributes significantly to high concentrations of metals in the soil resulting in resistance to metals and consequentially to antibiotics by inherent microbes which may eventually spread to other pathogenic microbes thereby elevating disease burden due to antibiotic resistance. The study aimed at determining the co-occurrence of resistance of bacteria isolated from metal-contaminated soil to heavy metals and subsequently, antibiotics. Metal-tolerant bacteria were randomly isolated from top soils from a battery waste site using the pour plate method. Selected isolates were identified using biochemical tests, then, subjected to elevating supplemented concentrations of different metal salts at 100-500 μg/mL to determine the minimum inhibitory concentration. Isolates tolerant to minimum three metals up to 400 μg/mL were subjected to Sulfamethoxazole-trimethoprim (25 μg), Imipenem (10 μg), Amoxicillin (30 μg), Ciprofloxacin (10 μg) and Tigecycline (15 μg) and observations interpreted using the guiding principle of the Clinical and Laboratory Standards Institute. Metal concentrations in the soils exceeded permissible limits. In total, 16 isolates were selected and identified as Proteus sp. (1), Pseudomonas spp. (5), Enterobacter spp. (2), Klebsiella spp. (2), Escherichia spp. (3), Raoultella spp. (2) and Rahnella sp. (1). Thirteen (81.25 %) of all isolates showed multi-resistance to the metals and seven exhibited multidrug-resistance, with 4 (57.1 %) showing resistance to three different classes of antibiotics and 3 (42.9 %) showed resistance to four antibiotic classes. Heavy metal-tolerant bacteria isolated from this study possess co-selection potentials as they showed resistance to different metals and antibiotics classes which is a concern to public health.
PubMed: 38298043
DOI: 10.5620/eaht.2023024 -
Chemosphere Mar 2024Harmful algal blooms (HABs) due to eutrophication are becoming a serious ecological disaster worldwide, threatening human health and the optimal balance of aquatic...
Harmful algal blooms (HABs) due to eutrophication are becoming a serious ecological disaster worldwide, threatening human health and the optimal balance of aquatic ecosystems. The traditional approaches to eradicate HABs yield several drawbacks in practical application, while microbial algicidal technology is garnering mounting recognition due to its high efficiency, eco-friendliness, and low cost. In our previous study, we isolated a bacterium strain Raoultella sp. S1 from eutrophic water with high efficiency of algicidal properties. This study further investigated the flocculation and inactivation efficiency of S1 on Microcystis aeruginosa at different eutrophic stages by customizing the algal cell densities. The supernatant extract of S1 strain exhibited remarkable flocculation and inactivation effects against low (1 × 10 cell/mL)and medium (2.7 × 10 cell/mL)concentrations of algal cells, but unexceptional for higher densities. The results further revealed that algal cells at low and medium counts manifested a more apparent antioxidant defense response, while the photosynthetic efficiency and relative electron transport rate were considerably reduced within 24 h. TEM observations confirmed the disruption of thylakoid membranes and cell structure of algal cells by algicidal substances. Moreover, TMT proteomics revealed alterations in protein metabolic pathways of algal cells during the flocculation and lysis stages at the molecular biological level. This signified that the disruption of the photosynthetic system is the core algicidal mechanism of S1 supernatant. In contrast, the photosynthetic metabolic pathways in the HABs were significantly upregulated, increasing the energy supply for the NADPH dehydrogenation process and the upregulation of ATPases in oxidative phosphorylation. Insufficient energy provided by NADPH resulted in a dwindled electron transport rate, stagnation of carbon fixation in dark reactions, and blockage of light energy conversion into chemical energy. Nonetheless, carbohydrate metabolism (gluconeogenesis and glycolysis) proteins were down-regulated and hampered DNA replication and repair. This study aided in unveiling the bacterial management of eutrophication by Raoultella sp. S1 and further arrayed the proteomic mechanism of algal apoptosis.
Topics: Humans; Microcystis; Proteomics; Ecosystem; NADP; Harmful Algal Bloom; Enterobacteriaceae
PubMed: 38272139
DOI: 10.1016/j.chemosphere.2024.141287 -
Journal of Dairy Science Jun 2024Antimicrobial resistance has become a global public health concern, and antibiotic resistance genes (ARG) in food are a research focus. In China, probiotics and...
Metagenomics reveals differences in the composition of bacterial antimicrobial resistance and antibiotic resistance genes in pasteurized yogurt and probiotic bacteria yogurt from China.
Antimicrobial resistance has become a global public health concern, and antibiotic resistance genes (ARG) in food are a research focus. In China, probiotics and pasteurized yogurts are the 2 main types of commercially available yogurt, but the distribution and differences of antibiotic-resistant bacteria and gene types in these products are not well known. This study used a shotgun metagenomic approach to analyze 22 different types of yogurt collected from 9 main yogurt-producing areas in China; each type of yogurt included 8 different batches of samples. The abundance and diversity of bacteria identified in probiotic yogurt were significantly higher than those in pasteurized yogurt, with Acetobacter, Raoultella, and Burkholderia identified as unique and highly abundant genera in probiotic yogurt. Similarly, the abundance of Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was higher than that in pasteurized yogurt. A total of 1,149 ARG subtypes belonging to 16 ARG types were identified, with the highest abundance of rifampicin, multidrug efflux pumps, and quinolone resistance genes detected. Network analysis revealed significant nonrandom co-occurrence relationships between different types and subtypes of ARG in yogurt samples. A total of 44 ARG subtypes in pasteurized yogurt were potentially hosted by 36 bacterial genera, and in probiotic yogurt, 63 ARG were expected to be hosted by 86 bacterial species from 37 genera. These findings indicate potential safety issues in fermented dairy products and emphasize the need for a more hygienic environment when processing probiotic yogurt.
Topics: Yogurt; Probiotics; China; Metagenomics; Drug Resistance, Bacterial; Anti-Bacterial Agents; Drug Resistance, Microbial; Bacteria
PubMed: 38246555
DOI: 10.3168/jds.2023-23983 -
World Journal of Microbiology &... Jan 2024Due to the misuse and overuse of antibiotics, bacteria are now exposed to sub-minimum inhibitory concentrations (sub-MICs) of antibiotics in various environments. In...
Due to the misuse and overuse of antibiotics, bacteria are now exposed to sub-minimum inhibitory concentrations (sub-MICs) of antibiotics in various environments. In recent years, exposure of bacteria to sub-MICs of antibiotics has led to the widespread emergence of antibiotic-resistant bacteria. In this study, three bacterial species from the Enterobacteriaceae family (Raoultella ornithinolytica, Pantoea agglomerans and Klebsiella quasivariicola) were isolated from water. The antibiotic susceptibility of these bacteria to 16 antibiotics was then investigated. The effects of sub-MICs of four selected antibiotics (kanamycin, chloramphenicol, meropenem, and ciprofloxacin) on the growth, biofilm formation, surface polysaccharide production, siderophore production, morphology, and expression of the translational/transcriptional regulatory transformer gene rfaH of these bacteria were analysed. The MICs of kanamycin, chloramphenicol, meropenem, and ciprofloxacin were determined to be 1, 2, 0.03 and 0.03 µg/mL for R. ornithinolytica; 0.6, 6, 0.03 and 0.05 µg/mL for P. agglomerans; and 2, 5, 0.04 and 0.2 µg/mL for K. quasivariicola. The growth kinetics and biofilm formation ability decreased for all three isolates at sub-MICs. The surface polysaccharides of R. ornithinolytica and P. agglomerans increased at sub-MICs. There was no significant change in the siderophore activities of the bacterial isolates, with the exception of MIC/2 meropenem in R. ornithinolytica and MIC/2 kanamycin in K. quasivariicola. It was observed that the sub-MICs of meropenem and ciprofloxacin caused significant changes in bacterial morphology. In addition, the expression of rfaH in R. ornithinolytica and K. quasivariicola increased with the sub-MICs of the selected antibiotics.
Topics: Anti-Bacterial Agents; Meropenem; Enterobacteriaceae; Ciprofloxacin; Bacteria; Kanamycin; Chloramphenicol; Siderophores; Microbial Sensitivity Tests
PubMed: 38240926
DOI: 10.1007/s11274-023-03877-w -
Polymers Dec 2023The product of ozonolysis, glycero-(9,10-trioxolane)-trioleate (ozonide of oleic acid triglyceride, [OTOA]), was incorporated into polylactic acid/polycaprolactone...
The product of ozonolysis, glycero-(9,10-trioxolane)-trioleate (ozonide of oleic acid triglyceride, [OTOA]), was incorporated into polylactic acid/polycaprolactone (PLA/PCL) blend films in the amount of 1, 5, 10, 20, 30 and 40% /. The morphological, mechanical, thermal and antibacterial properties of the biodegradable PLA/PCL films after the OTOA addition were studied. According to DSC and XRD data, the degree of crystallinity of the PLA/PCL + OTOA films showed a general decreasing trend with an increase in OTOA content. Thus, a significant decrease from 34.0% for the reference PLA/PCL film to 15.7% for the PLA/PCL + 40% OTOA film was established using DSC. Observed results could be explained by the plasticizing effect of OTOA. On the other hand, the PLA/PCL film with 20% OTOA does not follow this trend, showing an increase in crystallinity both via DSC (20.3%) and XRD (34.6%). OTOA molecules, acting as a plasticizer, reduce the entropic barrier for nuclei formation, leading to large number of PLA spherulites in the plasticized PLA/PCL matrix. In addition, OTOA molecules could decrease the local melt viscosity at the vicinity of the growing lamellae, leading to faster crystal growth. Morphological analysis showed that the structure of the films with an OTOA concentration above 20% drastically changed. Specifically, an interface between the PLA/PCL matrix and OTOA was formed, thereby forming a capsule with the embedded antibacterial agent. The moisture permeability of the resulting PLA/PCL + OTOA films decreased due to the formation of uniformly distributed hydrophobic amorphous zones that prevented water penetration. This architecture affects the tensile characteristics of the films: strength decreases to 5.6 MPa, elastic modulus E by 40%. The behavior of film elasticity is associated with the redistribution of amorphous regions in the matrix. Additionally, PLA/PCL + OTOA films with 20, 30 and 40% of OTOA showed good antibacterial properties on , () and , making the developed films potentially promising materials for wound-dressing applications.
PubMed: 38201793
DOI: 10.3390/polym16010128 -
Zhonghua Yu Fang Yi Xue Za Zhi [Chinese... Dec 2023To explore the drug resistance mechanism and gene structure characteristics of a carbapenemase-producing novel incompatibility group plasmid pNY2385-KPC from . A...
To explore the drug resistance mechanism and gene structure characteristics of a carbapenemase-producing novel incompatibility group plasmid pNY2385-KPC from . A multi-drug resistant strain was obtained from urine samples of patients with fever in the emergency ward of Li Huili Hospital, Ningbo Medical Center. Bacterial species was preliminary identified and finally confirmed by 16S rRNA gene amplification and the average nucleotide identity alignment, respectively. The minimum inhibitory concentrations of the antimicrobial agents were determined by VITEK 2 Compact System. The complete genome sequence was obtained by "third-generation" sequencing methods, and then detailed annotation of gene function and comparative genomic analysis of plasmid structure were carried out by BLASTP/BLASTN, RefSeq, ConservedDomains, ResFinder, Isfinder, etc. The pNY2385-KPC carried by NY2385 belonged a novel incompatibility group, and contained and conjugative transfer (type Ⅳ secretory system, T4SS) genes, which could induce conjugative transfer. A total of 15 plasmids of the same type as pNY2385-KPC were retrieved by NCBI, which were from , and the rest were from , , , , and other bacteria, and were broad-host-range plasmids. The sequence comparative analysis of all 6 of the novel plasmid from showed that the structure of the novel plasmid had certain conserved property, with Tn variant structure carrying , and plasmid pCF1807-3 had both and . The pNY2385-KPC type plasmids in carried resistance gene, which were divided into two subtypes: single replicator and / complex replicator, belonging to broad-host-range plasmids. And as a mobile genetic element, the plasmids promote the spread of .
Topics: Humans; Citrobacter freundii; RNA, Ribosomal, 16S; Emergency Service, Hospital; Escherichia coli; Genomics
PubMed: 38186165
DOI: 10.3760/cma.j.cn112150-20230530-00419 -
Clinical Case Reports Jan 2024Antimicrobial resistance (AMR) is a public health challenge. It causes unresponsiveness to treatment with antimicrobials, leads to sepsis, septic shock, and increased...
KEY CLINICAL MESSAGE
Antimicrobial resistance (AMR) is a public health challenge. It causes unresponsiveness to treatment with antimicrobials, leads to sepsis, septic shock, and increased hospital mortality. This is compounded by new multidrug resistant organisms. We present and discuss a case of sepsis caused by a rare multi-drug resistant bacterium .
ABSTRACT
Antimicrobial resistance is a major public health concern worldwide, associated with nearly 5 million deaths. The highest mortality attributed to AMR is seen in sub-Saharan Africa. , , , contribute to most deaths attributed to AMR globally. However, other uncommon microorganisms have been implicated. Few cases of resistant, extended-spectrum beta-lactamase (ESBL) producing have been reported to cause sepsis worldwide. To our knowledge, no case of . -induced sepsis has been reported in our settings. We report a case of sepsis due to . in an injured young adult. We received a 36-year-old man, a professional banker involved in a road traffic accident 2 h before admission. He sustained a deep degloving wound on the right ankle with exposure of the lateral malleolus and presented with severe pain, and bleeding at the injury site. x-Rays confirmed a comminuted intra-articular distal tibia and fibular fracture. Surgical debridement and external fixation were aseptically done on the same day. Below knee amputation was done on the 7th day post-admission due to extensively injured and infected limb with sepsis. Local pus culture isolated ESBL-positive . susceptible only to meropenem, ciprofloxacin, and amikacin. Introducing these antibiotics on the 11th post-admission day averted sepsis and enhanced patient recovery. With the threat of AMR, newly emerging highly resistant microbes should be expected and suspected. Early recognition of sepsis and its focus and precise intervention with antimicrobials guided by specimen culture and susceptibility profile is highly recommended and should be standard practice. It highly reduces morbidity and mortality due to sepsis.
PubMed: 38173896
DOI: 10.1002/ccr3.8402 -
Veterinary World Nov 2023Antibiotic resistance is a major global health threat. The increasing prevalence of drug-resistant bacteria poses a serious challenge to the effective treatment of...
BACKGROUND AND AIM
Antibiotic resistance is a major global health threat. The increasing prevalence of drug-resistant bacteria poses a serious challenge to the effective treatment of infections in both humans and animals. Water is a major source of human and animal exposure to bacteria, and the presence of drug-resistant bacteria in water could present a severe threat to public health and animal production. This study investigated the presence of drug-resistant bacteria in Lam Pao Dam (LPD) water in Kalasin, Thailand.
MATERIALS AND METHODS
Ampicillin-resistant strains were obtained from LPD water and identified using 16s rDNA sequencing. Antibiotic resistance genes were detected by polymerase chain reaction using specific primers. The presence of antibiotic-resistant bacteria was evaluated using 16s amplicon analysis. The minimum inhibitory concentration (MIC) of strains against antibiotics was determined.
RESULTS
A total of 12 , 4 , and 4 isolates were resistant to ampicillin. Almost all strains harbored and genes, and two strains also harbored the gene. All four strains harbored the gene. The most abundant species in the LPD sample was , followed by and . The MICs of 10 strains against five antibiotics revealed that all strains were resistant to ampicillin but susceptible to meropenem, doripenem, ertapenem, and imipenem.
CONCLUSION
These findings suggest a high prevalence of drug-resistant bacteria in LPD water. This is a cause for concern, as it could spread antibiotic-resistant infections in the community.
PubMed: 38152267
DOI: 10.14202/vetworld.2023.2321-2328 -
Scientific Reports Dec 2023Environmental pollution is a global phenomenon and troublesome fact that poses a grave risk to all living entities. Via coupling carbonaceous feedstocks with outstanding...
Environmental pollution is a global phenomenon and troublesome fact that poses a grave risk to all living entities. Via coupling carbonaceous feedstocks with outstanding microbial activity, kinetic experiments were established using the consortium of Proteus mirabilis and Raoultella planticola, biochar-derived sunflower seed husk (SHB) and rice straw (RSB), and their composites, which investigated at 30 °C (150 rpm) to eliminate 700 mg L lead (120 h) and phenol (168 h) from synthetic wastewater. The derived biochars physicochemical properties of were studied. According to adsorption capacity (q), consortium-SHB composites and consortium-RSB composites removed lead completely (70 mg g) within 48 h and 66 h, respectively. Besides, phenol was remediated entirely after 42 h and 48 h by both composite systems (69.90 mg g), respectively, comparing with bacterial consortium only or parent SHB and RSB. Moreover, four kinetic models were studied to describe the bioremediation process. Fractional power and Elovich models could be recommended for describing the adsorption kinetics for lead and phenol removal by the studied biomaterials with high correlation coefficient (R ≥ 0.91 for Pb and ≥ 0.93 for phenol) and lower residual root mean square error (RMSE) and chi-square (X). Overall, bacterial consortium-biochar composites exhibited greater remediation of lead and phenol than the sum of each single bacterial consortium and biochar systems; reflecting synergistic interaction of adsorptive capability of biochar and metabolic performance of bacterial consortium, as denoted by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The current study addressed the successful design of employing functional remediating consortium immobilized on waste biomass-derived biochar as a conducive alternative eco-sorbent and economic platform to detoxify organic and inorganic pollutants.
Topics: Adsorption; Biodegradation, Environmental; Charcoal; Helianthus; Kinetics; Lead; Oryza; Phenol; Phenols; Seeds; Water Pollutants, Chemical; Water Purification
PubMed: 38081934
DOI: 10.1038/s41598-023-49036-x -
Acta Microbiologica Et Immunologica... Dec 2023Aim of this study was to explore molecular characteristics and resistance mechanisms of carbapenem-resistant Raoultella ornithinolytica (CR-ROR) isolated from patients...
Aim of this study was to explore molecular characteristics and resistance mechanisms of carbapenem-resistant Raoultella ornithinolytica (CR-ROR) isolated from patients in a hospital in China. Three CR-ROR strains were collected and bacterial identification was done by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) Vitek-MS and by digital DDH analysis. VITEK 2 compact system and Kirby-Bauer (K-B) disk diffusion were used for antimicrobial susceptibility testing. Whole genome sequencing was carried out using the Illumina platform NovaSeq sequencer. Abricate software was used for the prediction of antibiotic resistance genes of three CR-ROR strains. The phylogenetic tree was constructed through genome SNPs to investigate the genetic relationship of three CR-ROR strains. Three CR-ROR (WF1357, WF2441, and WF3367) strains were collected in this study. Two strains were isolated from neurosurgery (WF1357 and WF2441), and one was isolated from pulmonology department (WF3367). All strains harboured multiple antibiotic resistance genes. Two strains (WF1357, WF2441) carried the blaNDM-1 gene, one of the strains (WF3367) carried the blaKPC-2 gene. Three CR-RORs were resistant to different antimicrobial agents including carbapenems. The three CR-ROR strains collected in this study and 51 CR-ROR strain genomes downloaded from NCBI, were divided into six evolutionary groups (A-F). In this study, three CR-ROR strains were found to have a higher level of resistance to antibacterial agents and carried multiple antibiotic resistance genes. The CR-ROR strains carrying multiple antibacterial resistant genes require the stringent monitoring to avoid the spread of multidrug-resistant bacterial strains.
Topics: Humans; Carbapenems; Phylogeny; beta-Lactamases; Enterobacteriaceae; Anti-Bacterial Agents; Microbial Sensitivity Tests; Klebsiella pneumoniae
PubMed: 38063919
DOI: 10.1556/030.2023.02123