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.
Biofilms* ; Candida albicans* ; Candida* ; Cross Infection ; Mirabilis ; Proteus mirabilis* ; Proteus vulgaris* ; Proteus* ; Reverse Transcriptase Polymerase Chain Reaction ; Virulence ; Yeasts

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.
Humans ; Gene Deletion ; Nitrates ; Proteus mirabilis/genetics* ; Gene Knockout Techniques

High cholesterol is one of the important factors inducing cardiovascular and cerebrovascular diseases. Drug therapy is the main method for reducing cholesterol, but has the disadvantages such as high cost and side effects. Studies have shown that intestinal bacteria play important roles in cholesterol metabolism. However, there are few reports on the screening and functional evaluation of cholesterol-lowering intestinal bacteria. In this study, 36 bile-tolerant bacteria were screened from healthy people stool through culturomics using bovine bile acid or artificial mixed bile acids as substrates. Taking Lactobacillus rhamnosus GG (LGG) as a positive control, three bile acid concentration groups (0 g/L, 0.3 g/L, 3 g/L) were set up to evaluate the cholesterol-lowering ability of bile-tolerant bacteria in vitro. Ten bacteria (including Proteus mirabilis, Providencia stuartii, Proteus vulgaris et al) were identified as the dominant cholesterol-lowering bacteria. Six of the above bacteria, Proteus mirabilis, Providencia stuartii, Proteus vulgaris, Proteus penneri, Wohlfahrtiimonas chitiniclastica, Providencia rettger, were evaluated for their ability to reduce triglycerides in vitro and tolerance to artificial gastric juice. Comparing with strain LGG, the six bacteria showed better triglyceride-lowering ability in vitro. With the decrease of pH value of artificial gastric juice and the increase of treatment time, the survival rate of six bacteria decreased. The above screening experiments and functional evaluation provide a basis for further development of potential cholesterol-lowering bacterial products.
Animals ; Cattle ; Cholesterol ; Gammaproteobacteria ; Humans ; Proteus mirabilis ; Providencia

BACKGROUND: Disinfection is essential for the prevention of hospital infoction. Tego-51, one of the amphoteric surfactants based on the dodecyl-di( aminoethyl)-glycine, has been considered as an effctive disinfectant having a broad specturn of antimicrobial activity. We evaluated the disinfective activity of Tego-51 against several clinical isolates of bacteria and yeasts including Helicobacter pyiori. METHODS: Twenty three strains of vacteria including H. pylori, and a strain of yeast were exposed to the various concentrations (0.05%, 0.01%, 0.005%) of Tego-51 for the various periods (0.5, 1, 2, 4, 8, 16min). After the exposure to Tego-51 disinfectant, 0.01 mL of mixture of microorfanisms and Tego-51 was inoculated into brain-heart infusion broth, into Sabouraud dextrose agar. or Wilkins-Chalgren agar with 10% sheep blood, and incubated at 37 degrees C for 48 hours or in the Campy Pouch microaerophilic system. RESULTS: Most strains were killed within 30 seconds after an exposure to 0.01% of Tego-51, but Proteus mirabilis was eradicated after two minutes of exposure. At the concentration of 0.005 % concentration. P. mirabilis and Bacillus subtilis were killed after eight minutes od exposure. H. pylori was killed with 0.005% Tego-51within 30 seconds. Conslusions: This study showed that Tego-51disinfectant was effective for the disinfection of commonly isolated bacteria and yeast from hospital. It may be recommended that Tego-51 should be used at concentration greater than 0.1% for the effective disinfection of skin, instruments and hospital floors.
Agar ; Bacillus subtilis ; Bacteria ; Cross Infection ; Disinfection ; Glucose ; Helicobacter ; Mirabilis ; Proteus mirabilis ; Sheep ; Skin ; Surface-Active Agents ; Yeasts

BACKGROUND: Accurate detection of extended spectrum beta-lactamase (ESBL) is important because ESBLproducing organisms may appear susceptible to oxyimino- beta-lactams in standard susceptibility tests, but are considered to be clinically resistant to these drugs. And continued monitoring of isolation trend of ESBL-producing organisms is essential for the guideline settlement of antibiotic usage and infection control program. METHODS: Disk diffusion test using the Clinical and Laboratory Standards Institute's ESBL phenotypic confirmatory test were performed on 5,511 clinical isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis during the recent six years (April 2001-March 2007). The ESBL producer was defined as an organism showing an increase in the zone diameter of > or =5 mm for either cefotaxime or ceftazidime with clavulanic acid versus that without clavulanic acid (CTC confirmatory test, CZC confirmatory test, respectively). RESULTS: The ESBL-positive rates were 34.8% in K. pneumoniae, 9.3% in K. oxytoca, 8.4% in E. coli, and 6.5% in P. mirabilis. Among the ESBL-positive organisms, the detection rates of ESBL CTC and CZC confirmatory tests were as follows: 91.3% vs 68.7% in K. pneumoniae, 96.3% vs 44.4% in K. oxytoca, 94.8% vs 45.4% in E. coli, and 100% vs 20% in P. mirabilis. ESBL-producing K. pneumoniae had shown a continuously increasing trend from 24.3% in 2001 to 46.4% in 2006. CONCLUSION: Both of the ESBL confirmatory tests should be simultaneously tested for the accurate detection of ESBL-producing K. pneumoniae, K. oxytoca, E. coli, and P. mirabilis. In addition, an active infection control approach is needed for ESBL-producing K. pneumoniae.
beta-Lactamases* ; beta-Lactams ; Cefotaxime ; Ceftazidime ; Clavulanic Acid ; Diffusion ; Escherichia coli* ; Escherichia* ; Infection Control ; Klebsiella oxytoca ; Klebsiella pneumoniae ; Klebsiella* ; Mirabilis ; Pneumonia ; Proteus mirabilis* ; Proteus*

BACKGROUND: Accurate detection of organisms producing extended-spectrum beta-lactamase (ESBL) and AmpC beta-lactamase is very important for treatment of patients. However, unlike the ESBL confirmatory test, there are no guidelines for detection of organisms producing AmpC beta-lactamase. We evaluated a detection method using boronic acid (BA) for ESBL and AmpC beta-lactamase. METHODS: Clinical isolates of Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, and Proteus mirabilis showing intermediate resistance or resistance to cefoxitin (FOX) or positive for ESBL were tested. A > or =5 mm increase in zone diameter of ceftazidime/clavulanic acid/BA (CAZ/CA/BA) and/or cefotaxime/clavulanic acid/BA (CTX/CA/BA) versus CAZ/BA and/or CTX /BA was considered positive for ESBL. Likewise, a > or =5 mm increase in zone diameter of FOX/BA and/or cefotetan/BA (CTT/BA) versus FOX and/or CTT alone was considered positive for AmpC beta-lactamase. RESULTS: Among 622 clinical isolates, ESBL positive rates by the CLSI ESBL confirmatory test or by the BA method were 18.1% or 18.4% for E. coli, 38.3% or 40.4% for K. pneumoniae, 8.7% or 8.7% for K. oxytoca, and 14.8% or 14.8% for P. mirabilis, respectively. AmpC beta-lactamase positive rates using the BA method were 3.7% for E. coli, 33.3% for K. pneumoniae, 0% for K. oxytoca, and 7.4% for P. mirabilis. The detection rates of coproducing ESBL and AmpC beta-lactamase were 2.4% in E. coli 27.1% in K. pneumoniae, and 3.7% in P. mirabilis. CONCLUSION: The ESBL confirmatory method using BA was found to enhance the detection of ESBLs, even when potentially masked by AmpC beta-lactamase.
Bacterial Proteins ; beta-Lactamases ; Boron ; Cefoxitin ; Escherichia ; Escherichia coli ; Humans ; Klebsiella ; Klebsiella oxytoca ; Klebsiella pneumoniae ; Masks ; Mirabilis ; Penicillinase ; Pneumonia ; Proteus ; Proteus mirabilis

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.
Adult ; Aged ; beta-Lactamases* ; Brain ; Bronchoalveolar Lavage ; Cough ; Dexamethasone ; Follow-Up Studies ; Humans ; Lung ; Male ; Mirabilis ; Pneumonia* ; Proteus mirabilis* ; Proteus* ; Sputum ; Thorax ; Tomography, X-Ray Computed

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.
Anti-Bacterial Agents ; Bacteria ; Humans ; Methicillin ; Penicillins ; Postoperative Period* ; Proteus mirabilis ; Pseudomonas ; Staphylococcus aureus ; Stents

The present paper is aimed to explore the origins of Proteus mirabilis (PM) whorl swarming growth phenomenon. The whorl swarming growth phenomenon of PM was observed by changed bacterial culture inoculation time, humidity, vaccination practices, cultured flat placement, magnetic field, pH and other factors. Bacterial ring spiral direction of rotation is counterclockwise and the volatile growth process of PM was whorl swarming growth phenomenon. Spiro fluctuation phenomenon was of high frequency in the sealing tanks by cultured anytime inoculation, wherever inoculation technique applied or not, the presence or absence of the magnetic field, and wherever the dish position was. The experimental results showed that the whorl swarming growth phenomenon of PM requires specific pH environment, in which the facts may be relative to its genetic characteristics and the Earths rotation.
Cell Culture Techniques ; Hydrogen-Ion Concentration ; Magnetic Fields ; Proteus mirabilis ; growth & development

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 G_REMLIN to narrow the mutation library. Thereby, 18 potential single-point mutants were screened out. According to experimental verification, 7 mutants had melting temperature (T_m) improved, and the ΔT_m 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 T_m 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.
Enzyme Stability ; Lipase/chemistry* ; Molecular Dynamics Simulation ; Proteus mirabilis/metabolism* ; Solvents/chemistry*