Proteus Mirabilis Strains Research Articles

Outer Membrane Vesicles Formed by Clinical Proteus mirabilis Strains May Be Incorporated into the Outer Membrane of Other P. mirabilis Cells and Demonstrate Lytic Properties.

Outer membrane vesicles (OMVs) are extracellular structures, ranging in size from 10 to 300 nm, produced by Gram-negative bacteria. They can be incorporated into the outer membrane of a recipient's cells, which may enable the transfer of substances with lytic properties. Due to the scarce information regarding the OMVs produced by Proteus mirabilis, the aim of this study was to test the blebbing abilities of the clinical P. mirabilis O77 and O78 strains and to determine the blebs' interactions with bacterial cells, including their possible bactericidal activities. The production of OMVs was visualised by Transmission electron microscopy (TEM). The presence of OMVs in the obtained samples as well as the phenomenon of OMV fusion to recipient cells were confirmed by Enzyme-Linked ImmunoSorbent Assay (ELISA) and Western blotting assays. The bacteriolytic activity of the OMVs was examined against P. mirabilis clinical strains and reference Staphylococcus aureus and Escherichia coli strains. It was shown that each of the two tested P. mirabilis strains could produce OMVs which were able to fuse into the cells of the other strain. The lytic properties of the O78 OMVs against another P. mirabilis O78 strain were also demonstrated. This promising result may help in the future to better understand the mechanisms of the pathogenesis and to treat the infections caused by P. mirabilis.

Draft genome sequence of multidrug resistant Proteus mirabilis strain MAD23

Genome sequencing became one of the important tools for diagnosis of microorganisms. Proteus mirabilis is an enteric Gramnegative bacterium causes gastrointestinal and urinary tract infections in human and animals. Here, the draft sequencing of Proteus mirabilis (MAD23) strain was performed. The strain was collected from Chinese duck cecum suffering from diarrhea. Bacteria was identified by biochemical tests and characteristic swarming pattern on the plate. Antimicrobial susceptibility test was performed by VITEC-2 MS system. Also, draft genome sequencing was conducted using the Illumina platform NovaSeq sequencer. The genome is about 3,729,695 bp long, GC content is of 38.9%., number of contigs is 123, largest contig is 137547pb, smallest contig is 513, total of protein-coding sequences (CDSs) is 3410, and number of RNA genes is 72. Genome Pairwise comparisons of Proteus mirabilis MAD23 with other vs. type strain was detected based on is DDH, GC content, δ- value, genome size and number of proteins. Neighbour-Joining phylogenetic trees show relationship between Proteus mirabilis MAD23 and the close strains of Proteus species based on 16S rRNA sequences. In addition, analysis of the sequence reveals presence of many antibiotic resistance genes as dfrA1, sul2, dfrA32, aadA2b, aph(3’)-Ia, aadA1, aph(6)-Id, aph(3’’)-Ib, ere(A), aadA1, aadA2b, tet(J), tet(C), floR, and Cat genes.These genes encoding the resistance to different antibiotics including Aminoglycosides, Macrolides, Aminocyclitol, Tetracycline and Amphenicol. This work is considered as an important study can help in more understanding of WGS in Proteus spp. and recognize the genes that related to antibiotic resistance in this pathogen.

Proteus mirabilis and Klebsiella variicola associated with onion bacterial streak and bulb rot

The bulb onion (Allium cepa) is second only to tomatoes in value of vegetable crops cultivated worldwide. Water-soaked lesions, bleaching and blight on leaves and slippery skin, sour skin, soft rot near the neck and centre rot on onion bulbs were observed in surveys of the onion fields, storage as well as fruit and vegetable markets of northwestern provinces of Iran in 2020. Thirty-four samples were collected from onion fields of East Azerbaijan, West Azerbaijan and Zanjan provinces and the central storage of Bonab city. Fifty bacterial strains were isolated from symptomatic samples. Pathogenicity of the strains was confirmed by inoculating on onion bulb cultivars Azarshahr and Ghermez Anari. Twenty-eight strains were able to induce soft rot on the inoculated sites of cut onion bulbs. Onion bulbs turned dark brown at lesion sites and became odorous over time. All pathogenic strains were Gram-negative, facultative aerobic and catalase positive. Strains mainly varied in starch and aesculin hydrolysis, potato rot and hypersensitive reaction. Pathogenic strains separated into four groups based on phenotypic assays. In the phylogenetic tree based on concatenated sequences of gyrB and infB genes, the strains were divided into four clusters containing the type strains of Enterobacter ludwigii, Klebsiella variicola, Proteus mirabilis and Pantoea agglomerans, confirming their identity as belonging to these four species. This is the first report of P. mirabilis as a plant pathogen and of K. variicola as a causal agent of onion bulb rot. Moreover, this is the first report of E. ludwigii and P. agglomerans associated with onion bulb rot in Iran.

Microbiological Surveillance of Salmonella Strains in the Effluents of the Teaching Hospital (CHU) of Yopougon and Cocody, Côte d'Ivoire

Diarrhoeal diseases are a major public health problem worldwide, with salmonellosis being a leading cause of foodborne illness in humans. Environmental pollution from healthcare activities, particularly from the discharge of hospital effluent into urban sewer systems, poses a significant threat. These effluents can carry microorganisms, antibiotic residues and detergents that contribute to the development and spread of bacterial multiresistance. In Abidjan, the capital of Côte d'Ivoire, hospital wastewater is not treated before being discharged into the sewer system. This untreated wastewater eventually flows into the Ebrié lagoon, a critical water source for many local communities. The dependence of the lagoon's population on these waters raises significant public health concerns, particularly with regard to potential contamination with pathogenic bacteria such as Salmonella. The aim of this study was to assess the presence of Salmonella in hospital wastewater to understand the risk of contamination and to inform potential mitigation strategies. A total of 60 wastewater samples were collected: 30 from the teaching hospital (CHU) of Yopougon and 30 from Cocody. Upon analysis, no Salmonella sp strains were detected in any of the samples. However, 28 bacterial strains exhibiting characteristics similar to Salmonella were isolated, suggesting the presence of potentially virulent pathogens. In Yopougon's samples, 14 strains of Proteus mirabilis and 2 strains of Klebsiella sp were identified. In Cocody 's samples, 12 strains of Citrobacter freundii sp were isolated. These findings highlight the importance of monitoring and treating hospital wastewater to prevent the spread of potentially harmful bacteria into the environment.

Genetic characteristics of chromosomally integrated carbapenemase gene (blaNDM−1) in isolates of Proteus mirabilis

ObjectiveThis study aims to conduct an in-depth genomic analysis of a carbapenem-resistant Proteus mirabilis strain to uncover the distribution and mechanisms of its resistance genes.MethodsThe research primarily utilized whole-genome sequencing to analyze the genome of the Proteus mirabilis strain. Additionally, antibiotic susceptibility tests were conducted to evaluate the strain’s sensitivity to various antibiotics, and related case information was collected to analyze the clinical distribution characteristics of the resistant strain.ResultsStudy on bacterial strain WF3430 from a tetanus and pneumonia patient reveals resistance to multiple antibiotics due to extensive use. Whole-genome sequencing exposes a 4,045,480 bp chromosome carrying 29 antibiotic resistance genes. Two multidrug-resistant (MDR) gene regions, resembling Tn6577 and Tn6589, were identified (MDR Region 1: 64.83 Kb, MDR Region 2: 85.64 Kbp). These regions, consist of integrative and conjugative elements (ICE) structures, highlight the intricate multidrug resistance in clinical settings.ConclusionThis study found that a CR-PMI strain exhibits a unique mechanism for acquiring antimicrobial resistance genes, such as blaNDM−1, located on the chromosome instead of plasmids. According to the results, there is increasing complexity in the mechanisms of horizontal transmission of resistance, necessitating a comprehensive understanding and implementation of targeted control measures in both hospital and community settings.

Screening of Probiotic Candidates Bacteria as Biocontrol of Aeromonas Hydrophila Pathogen Isolated from Mina Padi Cultivation Area

The agricultural activities in rice-farming system can have an impact on fish farming and the characteristics of bacterial community, especially pathogenic bacteria. Utilization of probiotics as environmentally friendly biotechnology products can be used to improve environmental quality and suppress the presence of pathogenic bacteria. This study aimed to select bacteria as probiotic agents from aquaculture ponds with the Rice-fish farming system. A total of 22 bacterial isolates were isolated from the water and sediment contained in the culture ponds. Based on the screening results, 15 isolates were confirmed as general non-pathogenic bacteria (Aeromonas sp.), 9 isolates had antibacterial activity against Aeromonas hyrophylla and 4 isolates showed high antibiotic sensitivity and were able to synergize. The results showed the Proteus mirabilis, Proteus penneri, Kurthia gibsonii and Bacillus cereus strains. Bacillus cereus strain LB8 has antibacterial activity that can inhibit the pathogen Aeromonas hydrophila with an inhibition zone of 8mm and has a very high sensitivity to antibiotics. These four isolates are able to work together synergistically and can be used as consortium probiotic bacterial agents to suppress the growth of pathogens.

Molecular Characterization and Tolerance Potential of Culturable Crude Oil-Degrading Microbes in Santa-Barbara River, Bayelsa State, Nigeria

There has been chronic contamination of the surrounding aquatic and terrestrial environments in the Niger Delta region of Nigeria due to the enormous activities of crude oil exploration. This study aimed to characterize and assess the crude oil tolerance potential of indigenous microbes from crude oil spills in Santa Barbara River, Bayelsa State, Nigeria, that could serve as potential consortia for bioremediation of the crude oil spills. Total crude oil hydrocarbon-utilizing bacteria count (THUBC) and total crude oil hydrocarbon-utilizing fungi count (THUFC) in the samples were determined with a culture-dependent spread plate technique. Bacterial and fungal isolates were characterised using standard phenotypic and 16S/Internal Transcribed Spacer region rRNA gene sequencing techniques, respectively. The tolerance of autochthonous bacterial isolates to different concentrations of crude oil was subsequently determined. THUBC and THUFC in crude oil-polluted water samples ranged from 1.88 log10 CFU/ml to 2.74 log10 CFU/ml and from 0.00 log10 CFU/ml to 1.70 log10 CFU/ml, respectively. Representative strains of Proteus mirabilis, Bacillus subtilis, Pseudomonas aeruginosa, Micrococcus luteus and Aspergillus flavus isolates obtained from crude oil-polluted water samples were deposited in the GenBank (NCBI) under accession numbers OQ969924, OQ969951, OQ969987, OQ970009 and OQ975908. Proteus mirabilis, Pseudomonas aeruginosa and Aspergillus flavus demonstrated the most significant tolerance to crude oil pollutants (minimum crude oil inhibitory concentrations (MIC) = 80%) followed by Bacillus subtilis and Micrococcus luteus (MIC= 40%). The findings from this study are pointers to the potential role of the microbial isolates as bioremediation consortia to remediate the polluted Santa Barbara River.

Biofabrication, spectroscopic, and photocatalytic studies of titania nanoparticles mediated by Proteus mirabilis strain NG-ABK-32 for smart applications

ABSTRACT Green fabrication of nanoparticles (NPs) is simple, pocket-friendly, easy, sustainable, and devoid of eco-toxicity issues. Thirty-five bacterial strains were isolated from ‘tie and dye’ effluent-contaminated soil and effluent samples and were identified using traditional methods. Following a dye decolourization assay, Proteus mirabilis strain (NG-ABK-32) emerged as the isolate with the highest potential to decolourize vat violet RR dye. Titania nanoparticles (TiO2 NPs) fabricated using NG-ABK-32 strain were characterized by UV-visible spectroscopy (UV-vis), Transmission Electron Microscopy (TEM), X-ray Diffraction (XRD), and Fourier Transform Infrared (FT-IR) spectroscopy. UV-Vis result displayed an absorption peak at 320 nm. The TEM image revealed monodispersed, spherical NPs possessing an average particle size of 3.18 nm. The crystallographic plane of rutile TiO2 NPs and high purity were confirmed by the XRD pattern. The average crystallite size was 52.53 nm. The synthesis of TiO2 NPs was further established from FT-IR by the presence of Ti-O, Ti-OH, and O-Ti-O functional groups. The synergistic treatment caused a significant reduction of total suspended solids (TSS), total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), and color (Pt.Co) of the effluent by 96.86%, 78.78%, 67.84%, 56.65%, 67.84%, and 72.09% respectively. Thus, this study confirmed the better efficiency of combining biological (NG-ABK-32) pre-treatment with photocatalytic degradation post-treatment using the synthesized TiO2 NPs in the treatment of ‘tie and dye’ effluent compared to the application of the TiO2 NPs as a single treatment method.

A multicentre evaluation of the NG-test DetecTool OXA-23 for the rapid detection of OXA-23 carbapenemase directly from blood cultures.

A multicentre study evaluating NG-Test DetecTool OXA-23 for the detection of OXA-23 carbapenemase directly from positive blood cultures (PBCs). The NG-Test DetecTool OXA-23 is an immunoassay that integrates a sample preparation device. We evaluated NG-Test DetecTool OXA-23 on 189 spiked and 126 clinical PBCs. The clinical samples' standard-of-care procedure consisted of bacterial identification from the first day of positivity by MALDI-TOF MS, conventional culture and antimicrobial susceptibility testing. The immunoassay results were verified molecularly. The strains used for the spiked samples consisted of well-characterized Acinetobacter baumannii and Proteus mirabilis strains. The NG-Test DetecTool OXA-23 was evaluated on 315 PBCs and revealed sensitivity of 100% (95% CI: 98.21%-100.00%) and specificity of 100% (95% CI: 96.73%-100.00%). It provided 204 true-positive results for OXA-23 in 196 bottles with carbapenem-resistant A. baumannii (CRAB) and 8 bottles with carbapenem-resistant P. mirabilis and also provided 111 true-negative results. There were no false-positive and no false-negative results. Among the 315 PBCs studied, 83 clinical blood cultures collected in the ICU of a Greek university hospital, which were tested prospectively, all yielded CRAB, and OXA-23 was correctly detected in all samples from the first day of positivity using the NG-Test DetecTool OXA-23. The NG-Test DetecTool OXA-23 has exhibited excellent sensitivity and specificity for OXA-23 detection in PBCs and can provide valuable information for appropriate selection of antibiotic therapy and early implementation of infection control measures.

Bacteriological Study of Proteus mirabilis Isolated from Different Clinical Samples

Abstract: This study focuses on isolating and identifying 17 strains of Proteus mirabilis from a total of 135 clinical samples obtained from patients who visited Hila Teaching Hospital between October 2014 and February 2015. The isolates collected from patients diagnosed with urinary tract infections accounted for 11 cases or 64.7% of the total. In contrast, patients with ear infections contributed 3 cases, making up 17.6% of the total. In addition, the isolates acquired from patients with diarrhea, wound, and vaginal infection each accounted for 1 (5.9%) of the total cases. The collected isolates have been cultivated on specialized media and identified using biochemical reactions.
 Some virulence factors of all isolates are studied, and the results showed that all bacterial isolates 17(100%) produced hemolysin, urease, Bacteriocin (proticin), and swarming, while 16(94.1%) of isolate produced beta-lactamase. Antibiogram of P. mirabilis isolates has been studied and it has been found that all isolates were entirely resistant to Imipenem 17(100%), while most of the P. mirabilis isolates were sensitive to Ertapenem so the resistant only 3(17.6%). Furthermore, the resistance of isolates to Amoxicillin and Cefotaxime 14(82.3%), also 9(52.9%) of them were resistant to Amoxiclave, 11(64.7%) of them were resistant to Ceftriaxone and 4(23.5%) of them were resistant to Cefepime Clavulanic acid.

Inhibitory Effects of Biosynthesized Copper Nanoparticles on Biofilm Formation of Proteus mirabilis

This study aimed to explore whether green synthesized copper nanoparticles (CuNPs) can function as an anti-biofilm agent produced by P. mirabilis. The nanoparticles were synthesized from cells free extract of P. mirabilis. Characterization of biosynthesized copper nanoparticles was carried out to determine the chemical and physical properties of the product using atomic-force microscopy (AFM), transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD) and UV-visible spectroscopy. The hexagonal structure was confirmed by XRD, size range was marked 13-19nm by TEM. FESEM was used to confirm the surface morphology. AFM analysis was used to reveal the roughness and distribution of nanoparticles. UV–visible spectra of the synthesized nanoparticles recorded a maximum peak at 380 nm. Copper nanoparticles showed remarkable biofilm inhibitory effects on wild type strains of multidrug resistant Proteus mirabilis. After incubation for 24 and 48 hours at 37oC with 128 μg/ml sub minimum inhibitory concentration (MIC) of CuO nanoparticles, strong biofilm producer strains showed weak biofilm production. Down regulation changes in LuxS expression using real time PCR technology were detected after treatment with copper nanoparticles of these strains.

Screening and Characterization of Streptomyces spp. Isolated from Soil Producing a Potential Inhibitors of the Proteus mirabilis

Proteus mirabilis is a common cause of urinary tract infections and other nosocomial infections that can lead to severe health consequences. Despite the availability of various antibiotics, the increasing prevalence of multidrug-resistant (MDR) strains of Proteus mirabilis has necessitated the development of novel therapeutic compounds. The ability of species to produce a wide variety of secondary metabolites, such as antibiotics Streptomyces, immunosuppressants, and antivirals, is well known. In this study, a Streptomyces strain was isolated from soil near saltwater bodies, and its secondary metabolic extract was evaluated for its antimicrobial activity against Proteus mirabilis. The Streptomyces isolate demonstrated significant antimicrobial activity for Proteus mirabilis, with a minimum inhibitory concentration (MIC) of 34 µg/mL. The antimicrobial potential of the extract was confirmed through additional examination of the metabolite extract using deterministic assays, such as nucleic acid and protein release and time-kill curve assay. Molecular identification of the Streptomyces strain showed similarity with Streptomyces triticirhizae. GC-MS analysis of the extract revealed the presence of compounds such as Octadecanoic acid and n-Hexadecanoic acid, which are frequently associated with potent antimicrobial activity. HR-LCMS analysis revealed the presence of compounds such as Neomycin, Polymyxin B, and Maculosin, which also have potent antimicrobial activity. These findings strongly indicate the potential of the Streptomyces metabolite extracts as a novel therapeutic compound against Proteus mirabilis.

Isolation and Characterization of the Acadevirus Members BigMira and MidiMira Infecting a Highly Pathogenic Proteus mirabilis Strain.

Proteus mirabilis is an opportunistic pathogen and is responsible for more than 40% of all cases of catheter-associated urinary tract infections (CAUTIs). Healthcare-associated infections have been aggravated by the constant emergence of antibiotic-resistant bacterial strains. Because of this, the use of phages to combat bacterial infections gained renewed interest. In this study, we describe the biological and genomic features of two P. mirabilis phages, named BigMira and MidiMira. These phages belong to the Acadevirus genus (family Autographiviridae). BigMira and MidiMira are highly similar, differing only in four missense mutations in their phage tail fiber. These mutations are sufficient to impact the phages' depolymerase activity. Subsequently, the comparative genomic analysis of ten clinical P. mirabilis strains revealed differences in their antibiotic resistance profiles and lipopolysaccharide locus, with the latter potentially explaining the host range data of the phages. The massive presence of antimicrobial resistance genes, especially in the phages' isolation strain P. mirabilis MCS, highlights the challenges in treating infections caused by multidrug-resistant bacteria. The findings reinforce BigMira and MidiMira phages as candidates for phage therapy purposes.

In vitro effects of deferoxamine on antibiotic susceptibility in Gram-negative bacteria.

Iron is a vital element for the growth of bacteria. Bacteria use several strategies to scavenge iron, such as siderophores, which are thought to be important virulence components. The mammalian host uses various iron-binding substances to make iron unavailable for bacterial uptake. Deferoxamine (DFO) is a semi-synthetic iron chelator that has been licensed for medical use. Iron chelators like DFO may provide an alternative therapeutic technique for treating Gram-negative bacteria infections, which frequently display multidrug resistance. We assumed that iron deprivation or interactions with the cell membrane caused by DFO or increased siderophore synthesis may cause the inhibition or inactivation of proteins and enzymes necessary for critical processes in bacteria. Additionally, we proposed that these bacterial alterations might be the origin of synergistic interactions between DFO and several antibiotics. To test this hypothesis, we used disc diffusion, broth microdilution and checkerboard synergy testing methods on combinations of DFO with ceftriaxone, cefepime, meropenem, amikacin, levofloxacin, and tigecycline, respectively, in a total of 55 isolates (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, and Proteus mirabilis strains - 11 isolates for each genus). No synergistic or antagonistic interactions were observed between DFO and the tested antibiotics in the E. coli, K. pneumoniae, P. aeruginosa, and A. baumannii isolates, while the addition of DFO significantly increased the inhibition zone diameters of cefepime, amikacin, meropenem, tigecycline, and levofloxacin in P. mirabilis isolates. According to the checkerboard synergy results, a synergistic interaction was found between DFO and tigecycline, cefepime and amikacin for P. mirabilis isolates. Among the investigated bacteria, a synergy between antibiotics and DFO was only discovered against P. mirabilis. We do not believe that this entirely disproves our hypothesis, though. The production of siderophores triggered by the increased metabolic activity of actively proliferating bacteria at the infection site may provide better results. Therefore, expanding these investigations and developing infection models through animal testing would be advantageous.

Uropathogenic bacteria and deductive genomics towards antimicrobial resistance, virulence, and potential drug targets.

Urinary tract infections (UTIs) are among the most prevalent bacterial infections affecting people in inpatient and outpatient settings. The current study aimed to sequence the genome of uropathogenic Escherichia coli strain CUI-B1 resourced from a woman having uncomplicated cystitis and pyelonephritis. Followed by deductive genomics towards potential drug targets using E. coli strain CUI-B1, strain O25b: H4-ST131, Proteus mirabilis strain HI4320, Klebsiella pneumoniae strain 1721, and Staphylococcus saprophyticus strain ATCC 15305 uropathogenic strains. Comparative genome analysis revealed that genes related to the survival of E. coli, P. mirabilis, K. pneumoniae, and S. saprophyticus, such as genes of metal-requiring proteins, defense-associated genes, and genes associated with general physiology, were found to be highly conserved in the genomes including strain CUI-B1. However, the genes responsible for virulence and drug resistance, mainly those that are involved in bacterial secretion, fimbriae, adherence, and colonization, were found in various genomic regions and varied from one species to another or within the same species. Based on the genome sequence, virulence, and antimicrobial-resistant gene dataset, the subtractive proteomics approach revealed 22 proteins mapped to the pathogen's unique pathways and among them, entB, clbH, chuV, and ybtS were supposed to be potential drug targets and the single drug could be utilized for all above-mentioned strains. These results may provide the foundation for the optimal target for future discovery of drugs for E. coli-, P. mirabilis-, K. pneumoniae-, and S. saprophyticus-based infections and could be investigated further to employ in personalized drug development.

Construction and biological characterization of a Proteus mirabilis strain with modABC gene deletion

To construct a modABC gene knockout strain of Proteus mirabilis and explore the effect of modABC gene deletion on biological characteristics of Proteus mirabilis. Fusion PCR was used to obtain the fusion gene of modABC and the kanamycin-resistant gene Kn, which was ligated with the suicide vector pCVD442 and transduced into Proteus mirabilis. The modABC gene knockout strain of Proteus mirabilis was obtained after homologous recombination with the suicide vector. PCR and Sanger sequencing were used to identify genomic deletion of modABC gene in the genetically modified strain. The concentration of molybdate in the wild-type and gene knockout strains was determined using inductively coupled plasma mass spectrometry (ICP-MS), and their survival ability in LB medium was compared under both aerobic and anaerobic conditions. PCR and sanger sequencing confirmed genomic deletion of modABC gene in the obtained Proteus mirabilis strain. The concentration of intracellular molybdenum in the modABC gene knockout strain was 1.22 mg/kg, significantly lower than that in the wild-type strain (1.46 mg/kg, P < 0.001). Under the aerobic condition, the modABC gene knockout strain grown in LB medium showed no significant changes in survival ability compared with the wild-type strain, but its proliferation rate decreased significantly under the anaerobic condition and also when cultured in nitrate-containing LB medium under anaerobic condition. Homologous recombination with the suicide vector can be used for modABC gene knockout in Proteus mirabilis. modABC gene participates in molybdate uptake and is associated with anaerobic growth of Proteus mirabilis in the presence of nitrate.

High virulence Proteus mirabilis strains cause acceleration of decay of fresh-cut fruits

The role of Proteus mirabilis on food safety has not been investigated before. Three P. mirabilis strains (swupm1, swupm2 and swupm3) isolated from fresh-cut fruits were shown to vary in swarming motility, with strains swupm1 and swupm2, but not swupm3 exhibiting the characteristic bull's-eye phenotype. Strains swupm1 and swupm2 grew faster and produced stronger biofilm than swupm3. These strains were all multidrug resistant and exhibited high virulence in Galleria mellonella (100% mortality at around 100 CFU inoculum) with swupm1 being the most virulent one. P. mirabilis was shown to be able to survive in fresh-cut cantaloupe at 4 °C and facilitate the growth of other bacteria. At 25 °C, P. mirabilis could significantly accelerate the decay of fresh-cut fruits. Headspace gas chromatography–ion mobility spectrometry (HS-GC-IMS) analysis showed that P. mirabilis strain swupm1 could cause dramatic changes in the volatile components of fresh-cut cantaloupe, such as ethyl acetate, ethanol and formic acid. This study indicates that P. mirabilis can accelerate the decay of fresh-cut fruits and that the virulence level of these strains seems to be closely associated with the adverse effect of such strains on food quality.

Genotypic characterization of a Proteus mirabilis strain harboring blaKPC-2 on the IncN plasmid isolated from a patient with bloodstream infection in China

BackgroundCarbapenemase is the predominant enzyme in the mechanism leading to Enterobacterales resistance to carbapenems, and the rapid spread of the blaKPC gene is a major public health concern. Here, we describe a carbapenem-resistant Proteus mirabilis strain XH983, which harbored a blaKPC-2-producing IncN plasmid, isolated from a bloodstream infection. MethodsWhole-genome sequencing and bioinformatics analysis were performed to assess the genetic environment of P. mirabilis XH983. Conjugation and transfer experiments were performed and the corresponding strains were confirmed by antimicrobial susceptibility testing. Phylogenetic and comparative genomic analysis were performed to explore the characteristics of carbapenem-resistant P. mirabilis isolates worldwide. ResultsP. mirabilis XH983 was isolated from the blood of a patient in Hangzhou, China. The genome of XH983 contained one 4128,916 bp circular chromosome and one 24,225 bp IncN plasmid harboring blaKPC-2. P. mirabilis XH983 had multiple resistance genes, conferring resistance to aminoglycosides [aph(3')-Ia, aph(3'')-Ib, aph(6)-Id, aac(3)-IId, aadA5, aadA1], β-lactams (blaKPC-2, blaTEM-1B), phenicol (cat, catA1), sulphonamide/trimethoprim (drfA1, drfA17, sul1, sul2) and tetracycline [tet(J)]. The phylogenetic tree showed that XH983 was present in a cluster of 30 isolates, all of which carried blaKPC-2 and most of them came from the same hospital as XH983, indicating the clonal spread of the cluster. ConclusionWe characterized carbapenem-resistant P. mirabilis clinical isolate XH983. The genome sequence of P. mirabilis XH983 provides information about resistance mechanisms of P. mirabilis carrying the blaKPC-2 plasmid and the potential spread of blaKPC-2.

Epidemiological Description and Detection of Antimicrobial Resistance in Various Aquatic Sites in Marseille, France.

Antibiotic resistance is a worldwide public health concern and has been associated with reports of elevated mortality. According to the One Health concept, antibiotic resistance genes are transferrable to organisms, and organisms are shared among humans, animals, and the environment. Consequently, aquatic environments are a possible reservoir of bacteria harboring antibiotic resistance genes. In our study, we screened water and wastewater samples for antibiotic resistance genes by culturing samples on different types of agar media. Then, we performed real-time PCR to detect the presence of genes conferring resistance to beta lactams and colistin, followed by standard PCR and gene sequencing for verification. We mainly isolated Enterobacteriaceae from all samples. In water samples, 36 Gram-negative bacterial strains were isolated and identified. We found three extended-spectrum β-lactamase (ESBL)-producing bacteria-Escherichia coli and Enterobacter cloacae strains-harboring the CTX-M and TEM groups. In wastewater samples, we isolated 114 Gram-negative bacterial strains, mainly E. coli, Klebsiella pneumoniae, Citrobacter freundii and Proteus mirabilis strains. Forty-two bacterial strains were ESBL-producing bacteria, and they harbored at least one gene belonging to the CTX-M, SHV, and TEM groups. We also detected carbapenem-resistant genes, including NDM, KPC, and OXA-48, in four isolates of E. coli. This short epidemiological study allowed us to identify new antibiotic resistance genes present in bacterial strains isolated from water in Marseille. This type of surveillance shows the importance of tracking bacterial resistance in aquatic environments. IMPORTANCE Antibiotic-resistant bacteria are involved in serious infections in humans. The dissemination of these bacteria in water, which is in close contact with human activities, is a serious problem, especially under the concept of One Health. This study was done to survey and localize the circulation of bacterial strains, along with their antibiotic resistance genes, in the aquatic environment in Marseille, France. The importance of this study is to monitor the frequency of these circulating bacteria by creating and surveying water treatments.

Epidemic characteristics of the SXT/R391 integrated conjugative elements in multidrug-resistant Proteus mirabilis isolated from chicken farm

This study was designed to depict prevalence and antimicrobial resistance characteristics of Proteus mirabilis (P. mirabilis) strains in 4 chicken farms and to probe the transfer mechanism of resistance genes. A total of 187 P. mirabilis isolates were isolated from 4 chicken farms. The susceptibility testing of these isolates to 14 antimicrobials showed that the multidrug resistance (MDR) rate was as high as 100%. The β-lactamase resistance genes blaOXA-1, blaCTX-M-1G, blaCTX-M-9G and colistin resistance gene mcr-1 were highly carried in the P. mirabilis isolates. An MDR strain W47 was selected for whole genome sequencing (WGS) and conjugation experiment. The results showed that W47 carried 23 resistance genes and 64 virulence genes, and an SXT/R391 integrated conjugative elements (ICEs) named ICEPmiChn5 carrying 17 genes was identified in chromosome. ICEPmiChn5 was able to be excised from the chromosome of W47 forming a circular intermediate, but repeated conjugation experiments were unsuccessful. Among 187 P. mirabilis isolates, 144 (77.01%, 144/187) isolates carried ICEPmiChn5-like ICEs, suggesting that ICEs may be the major vector for the transmission of resistance genes among MDR chicken P. mirabilis strains in this study. The findings were conducive to insight into the resistance mechanism of chicken P. mirabilis strains and provide a theoretical basis for the use of antibiotics for the treatment of MDR P. mirabilis infections in veterinary clinic.