Role of Proteus mirabilis flagella in biofilm formation / Papel de los flagelos de Proteus mirabilis en la formación de biofilms

Abstract Proteus mirabilis (P. mirabilis) is a common etiological agent of urinary tract infec-tions, particularly those associated with catheterization. P. mirabilis efficiently forms biofilms on different surfaces and shows a multicellular behavior called 'swarming', mediated by flagella. To date, the role of flagella in P. mirabilis biofilm formation has been under debate. In this study, we assessed the role of P. mirabilis flagella in biofilm formation using an isogenic allelic replacement mutant unable to express flagellin. Different approaches were used, such as the evaluation of cell surface hydrophobicity, bacterial motility and migration across catheter sections, measurements of biofilm biomass and biofilm dynamics by immunofluorescence and confocal microscopy in static and flow models. Our findings indicate that P. mirabilis flagella play a role in biofilm formation, although their lack does not completely avoid biofilm genera-tion. Our data suggest that impairment of flagellar function can contribute to biofilm prevention in the context of strategies focused on particular bacterial targets.

Resumen Proteus mirabilis (P mirabilis) es un agente etiológico común de infecciones del tracto urinario, en particular de aquellas asociadas con cateterización. P. mirabilis forma biofilms eficientemente en diferentes superficies y muestra un comportamiento multicelular llamado swarming, mediado por flagelos. Hasta el momento, el papel de los flagelos en la formación de biofilms de P. mirabilis ha estado en discusión. En este estudio, se evaluó el papel de los flagelos de P. mirabilis en la formación de biofilms, utilizando una mutante isogénica generada por reemplazo alélico, incapaz de expresar flagelina. Se utilizaron diferentes enfoques, como la evaluación de la hidrofobicidad de la superficie celular, de la movilidad y la migración bacteriana sobre secciones de catéteres y medidas de biomasa y de la dinámica del biofilm mediante inmunofluorescencia y microscopia confocal, tanto en modelos estáticos como de flujo. Nuestros hallazgos indican que los flagelos de P. mirabilis desempeñan un papel en la formación de biofilms, aunque su falta no suprime por completo su generación. Asimismo, evidencian que la interferencia de la función flagelar puede contribuir a evitar la formación de biofilms en el contexto de estrategias centradas en blancos bacterianos particulares.

A Core Genome Multilocus Sequence Typing Scheme for Proteus mirabilis / 生物医学与环境科学（英文）

OBJECTIVE@#A core genome multilocus sequence typing (cgMLST) scheme to genotype and identify potential risk clonal groups (CGs) in Proteus mirabilis.@*METHODS@#In this work, we propose a publicly available cgMLST scheme for P. mirabilis using chewBBACA. In total 72 complete P. mirabilis genomes, representing the diversity of this species, were used to set up a cgMLST scheme targeting 1,842 genes, 635 unfinished (contig, chromosome, and scaffold) genomes were used for its validation.@*RESULTS@#We identified a total of 205 CGs from 695 P. mirabilis strains with regional distribution characteristics. Of these, 159 unique CGs were distributed in 16 countries. CG20 and CG3 carried large numbers of shared and unique antibiotic resistance genes. Nine virulence genes ( papC, papD, papE, papF, papG, papH, papI, papJ, and papK) related to the P fimbrial operon that cause severe urinary tract infections were only found in CG20. These CGs require attention due to potential risks.@*CONCLUSION@#This research innovatively performs high-resolution molecular typing of P. mirabilis using whole-genome sequencing technology combined with a bioinformatics pipeline (chewBBACA). We found that the CGs of P. mirabilis showed regional distribution differences. We expect that our research will contribute to the establishment of cgMLST for P. mirabilis.

Serum Procalcitonin Guide in a Case of Proteus mirabilis Prosthetic Joint Infection

@#Infection is a dreaded complication in patients who have underwent arthroplasty and often very challenging to treat. It accounts for lesser than 1% of arthroplasty cases and although low in occurrence, requires appropriate investigations and management to successfully treat the condition. This case demonstrates a case of a rare microorganism with unusual antibiotic susceptibility causing a prosthetic joint infection and the use of serum procalcitonin level as guide in management of the patient.

Construction and biological characterization of a Proteus mirabilis strain with modABC gene deletion / 南方医科大学学报

OBJECTIVE@#To construct a modABC gene knockout strain of Proteus mirabilis and explore the effect of modABC gene deletion on biological characteristics of Proteus mirabilis.@*METHODS@#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.@*RESULTS@#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.@*CONCLUSION@#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.

Antibacterial Properties of Young and Mature Mango Leaves (Mangifera indica) Extract on Some Clinical Isolates

Aim: This study was carried out to investigate the antibacterial properties and efficacy of mango (Mangifera indica) leaf extracts on some clinical isolates as test rganisms. Study Design: The study employed statistical analysis of the data and interpretationPlace and Duration of Study: Young and mature mango leaves were collected from the Botanical Garden, Kenule Beeson Saro-Wiwa Polytechnic, Bori, Nigeria, and taken to the laboratory for analyses. Methodology: The samples were dried in an oven at 80oC for 3 days. Thereafter, 50 g of each ground mango leaf (young and mature leaves) were soaked separately in 500 ml of water, ethanol (95% v/v), and acetic acid (99.9% v/v) respectively for another 3 days. The soaked materials were filtered through Whatman No. 1 filter paper into sterile beakers and evaporated to dryness in a water bath at 80oC. The dried extracts obtained were reconstituted with water at concentrations of 100, 75, 50, and 25 mg/ml. Test organisms, Escherichia coli, Staphylococcus aureus, Salmonella typhi, Proteus mirabilis, Bacillus cereus, and Pseudomonas aeruginosa were obtained after proper laboratory screening of isolates from the diagnostic laboratory of the Rivers State University Teaching Hospital, Port Harcourt, Nigeria, for confirmation of identity and storage in universal bottles in a refrigerator. Sensitivity tests were carried out with the agar well diffusion method against the test organisms, using tetracycline as the standard control drug, with cultures incubated accordingly. The measured zones of inhibition were compared with the controls and interpreted as resistant, intermediate, or susceptible to mango extracts in accordance with the interpretive guidelines published by the National Committee for Clinical Laboratory Standards (NCCLS). Assay for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was also carried out. Results: Results obtained showed that acetic acid young leaf extract at 100mg/ml produced 50 % susceptibility and 50 % intermediate response of test bacterial species. Generally, at 100 mg/ml, acetic acid young leaf extracts yielded 50% susceptibility and 50% intermediate response among both Gram-positive and Gram-negative bacteria. Ethanolic extracts gave 100% intermediate sensitivity of Gram-negative species and 50% each of resistant and intermediate response in Gram-positive forms. Aqueous extracts also produced no susceptibility among the test organisms as there was 100% resistance. Extracts of mature mango leaves of all solvents and at all concentrations used yielded no susceptibility response among the test bacterial species on the NCCLS scale. Minimum inhibitory and bactericidal concentrations were found to range from 25 mg/ml to 50 mg/ml. Additionally, it was observed that the sensitivity of organisms to mango extracts increased with concentration.Conclusion: In conclusion, acetic acid has a better extracting potential than ethanol and water as a solvent for the extraction of mango parts. More so, young mango leaves extracted with acetic acid possess higher broad-spectrum antibacterial properties than the mature mango leaves extracted from the same plant. It is therefore recommended that young mango leaves, extracted with acetic acid, be used for the treatment of microbial infections at concentrations not below 50 mg/ml.

Pathogenic bacteria spectrum of infectious stones and experience of preventing stone recurrence / 中华泌尿外科杂志

Objective:To investigate the pathogenic bacteria profiles in preoperative urine bacterial cultures of patients with infected kidney stones and use antibacterial drugs to prevent recurrence.Methods:The data of 79 cases with infected kidney stones admitted to the Second Affiliated Hospital of Zhengzhou University from January 2017 to July 2021 were retrospectively analyzed, among whom 29 (36.7%) were male and 50 (63.3%) were female. The age ranged from 17-75 years, with a median age of 49.0 (40, 55) years. Fifteen cases (19.0%) combined hypertension, 13 cases (16.5%) combined diabetes mellitus, and 3 cases (3.8%) combined with cardiovascular disease. Fifty-one cases (64.6%) were diagnosed with cast infectious stones. All patients underwent surgical lithotripsy, and postoperative review of the urological computerized tomography (CT) revealed no residual stones defined as complete lithotripsy, and postoperative oral medication was continued to control infection and prevent stone recurrence. According to post-hospitalization compliance, patients were divided into high and low compliance groups. The high compliance group consisted of patients who returned to the hospital regularly for routine urinalysis and urine bacterial culture after discharge, followed the doctor's prescription for standardized antibacterial drug therapy, and complied with urease inhibitor therapy for ≥6 months. The low compliance group included patients who did not take sensitive antimicrobial drugs regularly and/or were unable to adhere to the medication even after the reduction of vinblastine due to adverse events such as tremor, palpitations, headache, anemia, or gastrointestinal discomfort. The recurrence of stones at 3, 6 and 12 months of follow-up was compared between the two groups.Results:Of the 79 cases in this group, 56(70.9%) were completely clear of stone after surgery. Thirty-three cases (41.8%) presented positive in preoperative urine bacterial culture, and the most common causative organism was Aspergillus oddus in 17 cases (21.5%), followed by Escherichia coli in 8 cases (10.1%) and Klebsiella pneumoniae in 3 cases (3.8%). Among the 17 positive cases of A. oddis, six were positive for ultra broad spectrum β-lactamases (ESBLs), 6/6 were resistant to ampicillin, cefazolin, and cotrimoxazole, 1/6 were resistant to amikacin, cefoxitin, and ticarcillin/stick acid, and none were resistant to imipenem, polymyxin, or aminotrans (0/6 cases). Of the cases, 11 were negative for ESBLs. Ten out of eleven cases were resistant to ampicillin. Furthermore, 8/11 cases were resistant to cefazolin, levofloxacin, ciprofloxacin, and cotrimoxazole and 1/11 were resistant to cefoxitin, cefaclor, furantoin, amikacin, and minocycline, and 0/11 were resistant to imipenem, ticarcillin/stick acid, aminotrans. ESBLs positive strains were resistant to 78.6% of the tested drugs (cefaclor, cefazolin, ceftazidime, furantoin, norfloxacin, levofloxacin, ciprofloxacin, cefoxitin, amoxicillin/rod acid, ticarcillin/rod acid, ampicillin, ceftriaxone, cefotaxime, cefuroxime, cefepime, gentamicin, cotrimoxazole, tobramycin, amikacin, tetracycline, chloramphenicol, and minocycline) at a lower rate of resistance than ESBLs positive strains. Of the eight positive cases of E. coli, seven were ESBLs positive, 7/7 were resistant to ampicillin, cefazolin, cefotaxime, cefuroxime, and cefepime, 1/7 were resistant to cefoxitin and minocycline, and 0/7 were resistant to imipenem, furantoin, or amikacin. One case was ESBLs negative and was resistant to all antimicrobial drugs except for ampicillin. Stone recurrence rates at 3, 6, and 12 months after discharge were 9.1%(4/44) and 31.4%(11/35), 13.6%(6/44), respectively, in the high compliance group, and 60.0%(21/35), 36.4%(16/44), and 71.4% (25/35), respectively, in the low compliance group. All differences were statistically significant.Conclusion:The most common pathogenic bacteria isolated from urine bacterial cultures of patients with infectious stones were A. chimaera, E. coli, and K. pneumoniae. The resistance rate of ESBLs-positive strains to antimicrobial drugs was significantly higher than that of ESBL-negative strains, and the resistance rate of antimicrobial drugs such as β-lactamase inhibitors, cefoxitin, amikacin, and imipenem was low. Combination therapy with standardized sensitive antimicrobial drugs and urease inhibitors significantly reduced the recurrence rate of stones among patients.

Improving the thermal stability of Proteus mirabilis lipase based on multiple computational design strategies / 生物工程学报

Proteus mirabilis lipase (PML) features tolerance to organic solvents and great potential for biodiesel synthesis. However, the thermal stability of the enzyme needs to be improved before it can be used industrially. Various computational design strategies are emerging methods for the modification of enzyme thermal stability. In this paper, the complementary algorithm-based ABACUS, PROSS, and FoldX were employed for positive selection of PML mutations, and their pairwise intersections were further subjected to negative selection by PSSM and GREMLIN to narrow the mutation library. Thereby, 18 potential single-point mutants were screened out. According to experimental verification, 7 mutants had melting temperature (Tm) improved, and the ΔTm of K208G and G206D was the highest, which was 3.75 ℃ and 3.21 ℃, respectively. Five mutants with activity higher than the wild type (WT) were selected for combination by greedy accumulation. Finally, the Tm of the five-point combination mutant M10 increased by 10.63 ℃, and the relative activity was 140% that of the WT. K208G and G206D exhibited certain epistasis during the combination, which made a major contribution to the improvement of the thermal stability of M10. Molecular dynamics simulation indicated that new forces were generated at and around the mutation sites, and the rearrangement of forces near G206D/K208G might stabilize the Ca2+ binding site which played a key role in the stabilization of PML. This study provides an efficient and user-friendly computational design scheme for the thermal stability modification of natural enzymes and lays a foundation for the modification of PML and the expansion of its industrial applications.

First report of bla GES-1 in Proteus mirabilis clinical isolates

Abstract Proteus mirabilis is one of the main pathogens causing urinary tract infections and sepsis. To our knowledge, this is the first report of a P. mirabilis hosting bla GES. The presence of these genes was determined using PCR and sequencing. We identified the presence of bla GES-1 in all three isolates. In addition, we identified the bla KPC-2 and bla NDM-1 genes in the two strains. These data emphasize the importance of monitoring and surveillance of all enterobacteria. The circulation of P. mirabilis strains carrying bla GES-1 constitutes a new scenario of resistance in this species and should be an epidemiological alert for global health.

Purple urine bag syndrome: an unusual clinical presentation

Purple Urine Bag Syndrome (PUBS) is a rare presentation of urinary tract infection caused by certain bacteria that produce sulphatases and phosphatases that bring about metabolism of tryptophan, leading to production of pigments indigo and indirubin that together impart purple colour of urine. It is a benign condition, most often associated with long term urinary catheterization, renal diseases, chronic constipation and female gender. Commonly implicated organisms include Proteus mirabilis, Klebsiella pneumoniae, Providencia stuartii. Diagnosis is made on urinary culture. Treatment includes reassurance and antibiotics for UTI. We present a case of purple urinary bag syndrome in a female patient of carcinoma stomach presenting with gastric outlet obstruction.

Time-kill study and morphological changes of Proteus mirabilis cells exposed to ethyl acetate crude extract of Lasiodiplodia pseudotheobromae IBRL OS-64

@#Aims: To investigate time-kill curve and morphological changes of Proteus mirabilis cells exposed to ethyl acetate crude extract of endophytic fungus, Lasiodiplodia pseudotheobromae IBRL OS-64, isolated from Ocimum sanctum. Methodology and results: Inhibitory effect of the fungal extract against the test bacteria via disc diffusion assay showed a fair antibacterial activity with diameter of inhibition zone was 12.0 ± 0.4 mm. The Minimal Inhibition Concentration (MIC) and Minimal Bactericidal Concentration (MBC) values of the ethyl acetate extract against P. mirabilis was 250 and 500 µg/mL, respectively. The value of MBC which is two-fold higher than MIC value indicated that the fungal extract exerted bactericidal effect on bacterial cells of P. mirabilis. Time-kill curve study revealed that the bactericidal effect of the crude extract towards test bacteria was both dose and time dependent. Scanning electron microscope (SEM) observation revealed that the bacterial cells of P. mirabilis exposed to fungal crude extract resulted in formation of pits, irregular shape of the bacterial cell and ultimately cell death beyond repair. Conclusion, significance and impact of the study: The time-kill curve study, and cell morphological changes suggested the potential of ethyl acetate extract of L. pseudotheobromae IBRL OS-64 against P. mirabilis infection by formation of cavities, irregular bacterial cell that leads to ultimate cell death and the extract may have pharmaceutical potential to be develop as antibacterial agent.

Optimization and immobilization of urease enzyme isolated from Proteus mirabilis on alginate beads

Urease enzyme was isolated from Proteus mirabilis and immobilized in alginate beads. Various parameters such as optimum pH, optimum temperature, pH stability, thermal stability, reusability, storage stability and substrate concentration were investigated and the findings were compared with free urease enzyme. İmmobilization yield was calculated as 85 %. Optimum temperature was found to be 40°C for free and immobilized urease. Thermal stability of the immobilized urease enzyme was significantly better than the free enzyme. Optimum pH for free and immobilized urease was be 7.0. Immobilized and free urease enzymes protected their stability at pH 7.0 and 8.0 in a similar way. Immobilized enzyme maintained 55% of their initial activity after 12 repeated use of enzyme. It was found that storage stability of immobilized enzyme was better than that of free enzyme. Km and Vmax values from the Lineweaver-Burk plots were calculated.

Mechanisms of plasmid-mediated quinolone resistance in Proteus mirabilis from urine / 实用医学杂志

Objective To investigate the prevalence of plasmid-mediated quinolone resistance(PMQR) in Proteus mirabilis clinical isolated from urine. Methods Antimicrobial susceptibility test was performed using the microdilution method.And PMQR gene qnrA,qnrB,qnrC,qnrD,qnrS,aac(6′)-Ib-cr,qepA were amplified by PCR,then the PCR positive products were sequenced to identify their genotypes. Results In 41 strains of Proteus mirabilis from urine,the resistant rates to ciprofloxacin and levofloxacin were 41.5% and 29.3%,respec-tively.Among all clinical isolates,qnrA1 gene was detected in 2 strains,qnrB2 gene in 3 strains.PMQR gene qn-rB,qnrC,qnrD,qnrS,aac(6')-Ib-cr and qepA were not detected in all strains.Conclusions Clinical isolates of Proteus mirabilis from urine carry PMQR genes.The prevalent principal genotypes are qnrA1 and qnrB2 in these iso-lates.They are related to low levels resistance toquinolone.

Antibiotics resistance of Proteus mirabilis isolated from patients with acute diarrhea / 天津医药

Objective To investigate antibiotics resistance of Proteus mirabilis isolated from stools of patients with acute diarrhea for the prevention and treatment of its infection and the rational use of antibiotics. Methods Stool samples of acute diarrhea patients were collected in the diarrhea outpatient clinic of the Second Hospital of Tianjin Medical University and Tianjin Medical University General Hospital from 2013 to 2014. Enrichment culture and biochemical identification were used to isolate and identify Proteus mirabilis, which were further performed antimicrobial susceptibility testing and class 1 integron detection. Extended spectrum β-lactamases (ESBLs) phenotype and ESBLs genes (TEM, OXA and CTX-M) were amplified by polymerase chain reaction (PCR), and sequencing were carried on in parts of suspected isolates. ESBLs-positive strains were analyzed by pulsed-field gel electrophoresis (PFGE). Results A total of 277 strains of non-repetitive Proteus mirabilis were isolated, and 268 of them were performed antimicrobial susceptibility testing (the remaining 9 strains failed to recover). Relative higher resistant rates were trimethoprim/sulfamethoxazole (30.2%), ampicillin (25.4%), nalidixic acid (25.7%), streptomycin (21.6%) and chloramphenicol (21.3%). The multiple drug resistance rate was 24.6% (66/268). The positive rate of class 1 integron was 22.8%(61/268). Resistance rates to third-generation cephalosporin, ciprofloxacin and imipenem were less than 10%, but 4 isolates were resistant to imipenem, third-generation cephalosporin, fluoroquinolones, trimethoprim/sulfamethoxazole, and chloramphenicol simultaneously. Three cefotaxime-resistant strains (1062, 1505 and 1650) were positive for ESBLs phenotype and harbored CTX-M extended-spectrum β-lactamase genes, among them 2 strains also carried TEM and/or OXA β-lactamase genes. The clustering analysis of pulsed-field gel electrophoresis (PFGE) displayed that the similarities between 1505 and 1650 were 85.7%, and the similarity with 1062 was 58.1%. Conclusion Proteus mirabilis isolated from patients with acute diarrhea in our city show significant multidrug resistance, high positive rate of class 1 integron, and emergence of ESBLs-positive strains resistant to imipenem and fluoroquinolones, which pose a threat to public health. Rational use of antibiotics is important in both clinical and nonclinical settings.

Case Report of Neonatal Proteus mirabilis Meningitis and Brain Abscess with Negative Initial Image Finding: Consideration of Serial Imaging Studies

Proteus mirabilis (P. mirabilis) meningitis in a neonate is rare, but its recognition is important because the disease progresses rapidly and has poor prognosis. A 4-day-old premature female infant born at 36 weeks and 5 days of gestation presented with symptoms of fever and icteric skin. Initial cerebrospinal fluid findings suggested bacterial meningitis, and treatment with antibiotics was started. On the third day, P. mirabilis growth was found in both blood and cerebrospinal fluid cultures and brain computed tomography revealed normal findings. The patient showed improved clinical symptoms, but brain magnetic resonance imaging on hospital day 18 revealed a brain abscess measuring 4.5×3.1×3.1 cm in the right frontal lobe. Cyst drainage was performed immediately and a catheter was inserted. Follow-up computed tomography revealed a tiny abscess remaining in the right frontal lobe, and follow-up magnetic resonance imaging later demonstrated marked interval regression in the size of the abscess. The patient was discharged on day 57 of hospitalization in good condition. Serial brain imaging should be considered in neonatal cases of P. mirabilis meningitis.

The Change of the Pathogen in Cultured Jones Tubes according to the Postoperative Periods

PURPOSE: To evaluate the change in pathogens in cultured Jones tubes used in lacrimal bypass surgery according to postoperative period and to provide basic data related to preventive antibiotics or functional lacrimal stent development. METHODS: Fifty patients who underwent Jones tubes removal were enrolled in this study. Removed Jones tubes were cultured to identify bacteria and were tested for antibiotic sensitivity. The results were further analyzed according to the period between lacrimal bypass surgery and tube removal. RESULTS: Among 50 cases, 24 (48%) showed cultured bacteria of Staphylococcus aureus, 5 (10%) were Pseudomonas, and another 5 (10%) were Gram-positive bacilli. Although Staphylococcus aureus was the most frequently cultured organism, Proteus mirabilis was the most common cultured organism in patients who underwent tube removal more than 10 years after lacrimal bypass surgery. There was no significant correlation between cultured organism and the period between lacrimal bypass surgery and tube removal. Eighty four percent of cultured Staphylococcus aureus showed resistance to penicillin, and 53% of cultured Staphylococcus aureus showed resistance to methicillin. CONCLUSIONS: Staphylococcus aureus was the most frequently cultured organism according to Jones tube-related lacrimal bypass surgery. A large proportion of cultured Staphylococcus aureus showed resistance to penicillin and methicillin. Proteus mirabilis should be considered the most common pathogen in patients more than 10 years after lacrimal bypass surgery.

Proteus vulgaris and Proteus mirabilis Decrease Candida albicans Biofilm Formation by Suppressing Morphological Transition to Its Hyphal Form

PURPOSE: Candida albicans (C. albicans) and Proteus species are causative agents in a variety of opportunistic nosocomial infections, and their ability to form biofilms is known to be a virulence factor. In this study, the influence of co-cultivation with Proteus vulgaris (P. vulgaris) and Proteus mirabilis (P. mirabilis) on C. albicans biofilm formation and its underlying mechanisms were examined. MATERIALS AND METHODS: XTT reduction assays were adopted to measure biofilm formation, and viable colony counts were performed to quantify yeast growth. Real-time reverse transcriptase polymerase chain reaction was used to evaluate the expression of yeast-specific genes (rhd1 and rbe1), filament formation inhibiting genes (tup1 and nrg1), and hyphae-related genes (als3, ece1, hwp1, and sap5). RESULTS: Candida biofilm formation was markedly inhibited by treatment with either living or heat-killed P. vulgaris and P. mirabilis. Proteus-cultured supernatant also inhibited Candida biofilm formation. Likewise, treatment with live P. vulgaris or P. mirabilis or with Proteus-cultured supernatant decreased expression of hyphae-related C. albicans genes, while the expression of yeast-specific genes and the filament formation inhibiting genes of C. albicans were increased. Heat-killed P. vulgaris and P. mirabilis treatment, however, did not affect the expression of C. albicans morphology-related genes. CONCLUSION: These results suggest that secretory products from P. vulgaris and P. mirabilis regulate the expression of genes related to morphologic changes in C. albicans such that transition from the yeast form to the hyphal form can be inhibited.

Encefalopatía asociada a la sepsis como presentación de una infección urinaria bacteriémica por Proteus mirabilis / Sepsis-associated encephalopathy as the first manifestation of bacteraemic urinary tract infection due to Proteus mirabilis

Se presenta un caso de una mujer de 56 años, quien presentó un cuadro de encefalopatía secundario a sepsis por infección urinaria por Proteus mirabilis . El cuadro respondió a tratamiento con ciprofloxacina y fue dada de alta al día 11.

We reported a case in a woman of 56 years of encephalopathy, secondary a urinary tract infection by Proteus mirabilis. The patient improved after 11 days of hospitalization, under treatment with ciprofloxacin.

Mechanisms and molecular typing of carbapenem-resistant Proteus mirabilis strains deficient in swarming motility / 中华微生物学和免疫学杂志

Objective To investigate the mechanism and epidemiological characteristics of carbap-enem-resistant Proteus mirabilis ( PM) strains deficient in swarming motility. Methods PM strains were isolated from Hangzhou General Hospital of CAPF ( Chinese People′s Armed Police Forces) during January 2013 to December 2014. Bacterial motility and flagella of the PM strains were observed through semi-solid agar culture and flagella staining. Pulsed-field gel electrophoresis ( PFGE) was performed for homology anal-ysis. Antimicrobial susceptibility test and phenotypic confirmatory test were also carried out. PCR analysis and DNA sequencing were performed to confirm the genotype of resistant genes. Plasmid electroporation and S1-PFGE in combination with Southern blot hybridization were used to determine the location of the carbap-enem-resistant genes. Genetic structure of the blaKPC-2 gene was obtained by PCR mapping. Results A total of 42 PM isolates deficient in swarming motility were screened out and the resistance rates to imipenem and meropenem were 57. 1% and 52. 4%, respectively. PCR analysis and DNA sequencing confirmed that 24 carbapenem-resistant PM isolates deficient in swarming motility carried blaKPC-2 gene and belonged to three clones as indicated by the results of PFGE. Southern blot hybridization indicated that the blaKPC-2 gene was located on plasmids varying in size (26 kb, 55 kb and 139 kb). In addition, some of the strains harbored several resistant genes, such as blaTEM-1 , blaCTX-M-65 and rmtB. The genetic structures of strains carrying blaKPC-2 gene were ISKpn8, blaKPC-2 and ISKpn6-like from upstream to downstream. Conclusion Compared with the PM strains with swarming motility, the carbapenem-resistance rate was significantly higher in these PM strains deficient in swarming motility. Carbapenemases KPC-2 played an important role in the carbapen-em-resistant PM strains deficient in swarming motility. There was a cloning spread trend for carbapenem-re-sistant PM strains in our hospital. Clinicians should pay more attention to the risk of spreading.

Pulmonary Pneumatocele in a Pneumonia Patient Infected with Extended-Spectrum beta-Lactamase Producing Proteus mirabilis / 결핵및호흡기질환

Pulmonary pneumatoceles are air-filled thin-walled spaces within the lung and are rare in adult cases of pneumonia. We report the case of a 74-year-old male who was admitted with a cough and sputum production. He had been treated with oral dexamethasone since a brain tumorectomy 6 months prior. Contrast-enhanced computed tomography (CT) of the chest revealed a large pneumatocele in the right middle lobe and peripheral pneumonic consolidation. Bronchoalveolar lavage was performed; cultures identified extended-spectrum beta-lactamase (ESBL) producing Proteus mirabilis. A 4-week course of intravenous ertapenem was administered, and the pneumatocele with pneumonia resolved on follow-up chest CT. To the best of our knowledge, this is the first reported case of pulmonary pneumatocele caused by ESBL-producing P. mirabilis associated with pneumonia.

Study on distribution of drug resistance gene and integron and analysis of genetic relationship of 20 isolates of Proteus mirabilis / 国际检验医学杂志

Objective To investigate the prevalence and resistance mechanisms of Proteus mirabilis in the ward of neurology de‐partment of our hospital .Methods For a total of 20 clinic isolates of Proteus mirabilis ,PCR were used for the detection of AmpC , ESBLs ,KPC and MBLs and then DNA sequencing was performed .The integrons were also detected by using PCR and then sequen‐cing was carried out .The genetic relationship between isolates were detected and analysed by pulsed‐field gel electrophoresis(PF‐GE) .The results of drug sensitivity tests were analysed .Results TEM‐1 and CTX‐M‐14 gene were found in all the 20 isolates ,the 10 isolates of Proteus mirabilis were also found carrying CMY‐2 gene .Class Ⅰ integrons were amplified from 19 strains carrying gene cassettes aacA4+cmlA1,dfrA12+orfF+aadA2and dfrA32+ereA+aadA2 respectively .PFGE analysis revealed that the 20 isolates were grouped into 11 PFGE types P1-P11 ,the 12 isolates of P1-P3 were same clones .The sensitive rates of the i‐solates to Meropenem ,Amikacin ,Aztreonam ,Ceftazidime and Tazocin were high .Conclusion Nosocomial transmission of the same clone of Proteus mirabilis was appeared in the ward of neurology department of our hospital .The predominance drug‐resistance genes were CTX‐M‐14 andCMY‐2 .The incidence of carrying class Ⅰ integrons was high ,and the major gene cassettes wereaacA4+cmlA1and dfrA12+orfF+aadA2.The 20 isolates were all sensitive to Meropenem ,Amikacin and Aztreonam .Other Clinical departments should also pay attention to the nosocomial infection caused by Proteus mirabilis and strengthen the infection control measures .