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Objective:To develop and evaluate a simple platform technology for developing static biofilms in a 96-well microtitre plate for various downstream applications. The technology allows monitoring of growth rate, biofilm formation and quantifying biofilm biomass by using crystal violet (CV) and safranin O (SO) staining over seven-day time periods for pathogens including clinical isolates most commonly associated with hard-to-treat wound infections.Method:A total of 157 bacteria including Acinetobacter, Enterobacter, Klebsiella, Pseudomonasand Staphylococcusspp. were used in the study. Bacterial growth was measured at 600nm optical density (OD). Biofilm formation was monitored and assessed quantitatively with CV at 570nm and SO staining at 492nm for one-, two-, three- and seven-day incubation periods.Results:Bacterial growth rate and static biofilm biomass in the 96-well plates varied for various strains tested. Both CV and SO staining showed similar results in the biomass, with SO assay displaying more reproducible data throughout the study. Most of the strains were metabolically active even at the seven-day incubation period. Microbial adherences of all bacterial strains on the plastic surface was assessed with CV staining: 28 Acinetobacter, 17 Staphylococcus, 12 Pseudomonasand four Enterobacterstrains were strong biofilm producers. Moderate biofilm-producing strains included 27 Staphylococcus, 14 Acinetobacter, eight Pseudomonasand three Enterobacter. Weak biofilm-producing strains included: 33 Staphylococcus, six Enterobacter, two Pseudomonasand one Acinetobacter. Only one Pseudomonas aeruginosastrain did not develop biofilm.Conclusion:Our results demonstrate the feasibility of using 96-well microtitre plates as a high-throughput platform for quantitative measurement and assessment of biofilm development over time. Studying microbial adherence or biofilm biomass generated on various surfaces using a high-throughput system could provide valuable information for in vitro testing and developing therapeutics for biofilm infections. Employing the biofilm testing platform described in this study makes it possible to simultaneously develop different biofilms formed by specific pathogens, and study potential association between the quantity of bacterial biomass and strength of a biofilm formed by specific wound pathogens. In addition, the described testing approach could provide an optimal model for standardised and high-throughput screening of candidate antibiofilm therapeutics.

Cold atmospheric plasmas (CAP) have been used in multiple medical fields and have become a promising medical technology. CAP-generating devices are safe and easy to operate and can now be manufactured at a low cost due to advancements in electronics and microchips. A primary application of CAP is as a broad-spectrum antimicrobial technology. With the high incidence of infections caused by drug-resistant microorganisms, a non-antibiotic based treatment modality such as CAP holds great therapeutic promise, particularly in the wound care field. In addition to its antimicrobial properties, CAP treatment enhances wound healing by increasing cutaneous microcirculation, monocyte stimulation, and keratinocyte proliferation. CAP has been used by dentists for disinfection of teeth, enhancing gingival fibroblast activity, and even teeth whitening. CAP can combat tumour growth by increasing the efficacy of antitumour therapeutic agents, reactivating apoptotic pathways, or down-regulating growth-related gene sites. Most of the health-care related research on CAP has occurred in the past 15 years; the field is relatively young and needs additional research, as well as confirmation of the existing supporting literature. The purpose of this report is to provide the reader with an overview of the therapeutic application of the cold plasma technology.

Genus Candida covers more than 50 species, half of which can cause infections in humans. Some of the Candida species exhibit drug resistance; therefore, there is an urgent need for rapid and accurate differentiation for rendering appropriate and effective management. Here, we report a new methodology employing real-time polymerase chain reaction (RTPCR) and melting temperature analyses (MTA) procedures. Fungal ribosomal internal transcribed spacer 2 (ITS2) has been confirmed with variable nucleotide sequences, which makes it possible to differentiate one species from another by checking their melting temperature following PCR amplification. The universal primers (panFg) covering entire ITS2 region, from 5.8S to 28S rRNA genes, were designed to differentially identify most Candida species with RTPCR-MTA procedure. Nucleic acids from five genomes of closely related Candida species, which were experimentally spiked into human blood, were extracted and amplified. PCR amplicons were called for melting temperature of Candida albicans (87.49°C), C. glabrata (86.85°C), C. krusei (90.24°C), C. parapsilosis (86.22°C), and C. tropicalis (86.08°C). The melting temperature of each amplicon was consistent and reproducible in three replicate experiments (SD ± 0.04-0.32). The new RTPCR-MTA methodology showed promise in differential diagnosis of closely related Candida species from environmental and clinical samples.

Brucellosis is a zoonotic infection transmitted from animals to human by ingestion of infected food products, direct contact with an infected animal, or inhalation of aerosols. Brucella infection-induced osteomyelitis may present only with nonspecific clinical and radiographic findings, mild elevations in serum inflammatory markers, as well as nonspecific histological changes. We studied a case of an Iraqi war veteran with multifocal vertebral body and left iliac bone lesions on radio nucleotide scans and magnetic resonance imaging, clinically suspected osteomyelitis possibly because of Brucella. Although histomorphological findings were nonspecific, consisting of chronic inflammatory cell infiltrate and reactive fibrosis, tissue gram and silver impregnation stains of bone biopsies were informative, revealing gram-negative coccobacilli consistent in size with Brucella species. Total nucleic acids were extracted from formalin-fixed paraffin-embedded tissues and amplified by sequential real-time polymerase chain reaction, targeting genes coding (1) outer membrane protein (omp-31) of Brucella species and (2) insertion sequence (IS711) of Brucella abortus (b-abt). Polymerase chain reaction results confirmed B. abortus as the causative pathogens for presumed diagnosis of Brucella osteomyelitis.

Burkholderia pseudomallei and B. mallei are two highly pathogenic bacteria responsible for melioidosis and glanders, respectively. Our laboratory developed hydrolysis probe-based real-time polymerase chain reaction assays targeting type three secretion system (TTS) and transposase family protein (TFP) of B. pseudomallei and B. malli, respectively. The assays were validated for target specificity, amplification sensitivity, and reproducibility. A bacterial DNA panel, composed of B. pseudomallei (13 strains), B. mallei (11 strains), Burkholderia species close neighbors (5 strains), and other bacterial species (17 strains), was prepared for specificity testing. Reference DNAs from B. pseudomallei and B. mallei bacterial cultures were used as controls for amplification, limit of detection, and reproducibility testing. The two TaqMan assays, Bp-TTS 1 and Bm-TFP, were optimized and applied in a retrospective study of archived cases from the Armed Forces Institute of Pathology. We tested 10 formalin-fixed paraffin-embedded blocks originally from autopsy specimens of patients who died of melioidosis or glanders during or after overseas tours in 1960s. Polymerase chain reaction results confirmed that DNA samples from formalin-fixed paraffin-embedded blocks of eight patients with melioidosis were positive for Bp-TTS 1 target and two patients with glanders were positive for Bm-TFP target.

RNase P from E. coli will cleave a RNA at a site designated in a complex with an external guide sequence (EGS). The location of the site is determined by the Watson-Crick complementary sequence that can be formed between the RNA and the EGS. Morpholino oligonucleotides (PMOs) that have the same base sequences as any particular EGS will not direct cleavage by RNase P of the target RNA at the expected site in three mRNAs. Instead, cleavage occurs at a secondary site that does not correspond exactly to the expected Watson-Crick sequence in the PMO. This cleavage in the mRNA for a drug resistance gene, CAT mRNA, is at least second order in the concentration of the PMOs, but the mechanism is not understood yet and might be more complicated than a simple second-order reaction. EGSs and PMOs inhibit the reactions of each other effectively in a competitive fashion. A basic peptide attached to the PMO (PPMO) is more effective because of its binding properties to the mRNA as a substrate. However, a PMO is just as efficient as a PPMO on a mRNA that is mutated so that the canonical W-C site has been altered. The altered mRNA is not recognizable by effective extensive W-C pairing to an EGS or PMO. The complex of a PMO on a mutated mRNA as a substrate shows that the dimensions of the modified oligonucleotide cannot be the same as a naked piece of single-stranded RNA.

External guide sequences (EGSs) targeting virulence genes from Yersinia pestis were designed and tested in vitro and in vivo in Escherichia coli. Linear EGSs and M1 RNA-linked EGSs were designed for the yscN and yscS genes that are involved in type III secretion in Y. pestis. RNase P from E. coli cleaves the messages of yscN and yscS in vitro with the cognate EGSs, and the expression of the EGSs resulted in the reduction of the levels of these messages of the virulence genes when those genes were expressed in E. coli.

Groups of mice were immunized either subcutaneously or intranasally with purified Brucella melitensis lipopolysaccharide (LPS) or with LPS as a noncovalent complex with Neisseria meningitidis group B outer membrane protein (LPS-GBOMP). Control mice were inoculated with sterile saline. Two doses of vaccine were given 4 weeks apart. Mice were challenged intranasally with virulent B. melitensis strain 16M 4 weeks after the second dose of vaccine. Sera, spleens, lungs, and livers of mice were harvested 8 weeks after challenge. The bacterial loads in the organs were determined by culture on brucella agar plates. Protective efficacy was determined by comparing the clearance of bacteria from organs of immunized mice with the clearance of bacteria from organs of control mice. At 8 weeks postchallenge there was significant protection from disseminated infection of spleens and livers of mice intranasally immunized with either vaccine compared to infection of control mice (P < 0.01). There was no significant difference in clearance of bacteria from the lungs of immunized mice and control mice. However, mice immunized subcutaneously with either LPS or LPS-GBOMP vaccine showed significant protection against infection of the spleen (P < 0.001), liver (P < 0.001), and lungs (P < 0.05). These results show that intranasal immunization of mice with either vaccine provided significant protection against disseminated infection of the spleen and liver but subcutaneous immunization of mice with the vaccines conferred significant protection against infection of the spleen, liver, and lungs.

ABSTRACTGroups of mice were immunized either subcutaneously or intranasally with purified Brucella melitensislipopolysaccharide (LPS) or with LPS as a noncovalent complex with Neisseria meningitidisgroup B outer membrane protein (LPS-GBOMP). Control mice were inoculated with sterile saline. Two doses of vaccine were given 4 weeks apart. Mice were challenged intranasally with virulent B. melitensisstrain 16M 4 weeks after the second dose of vaccine. Sera, spleens, lungs, and livers of mice were harvested 8 weeks after challenge. The bacterial loads in the organs were determined by culture on brucella agar plates. Protective efficacy was determined by comparing the clearance of bacteria from organs of immunized mice with the clearance of bacteria from organs of control mice. At 8 weeks postchallenge there was significant protection from disseminated infection of spleens and livers of mice intranasally immunized with either vaccine compared to infection of control mice (P< 0.01). There was no significant difference in clearance of bacteria from the lungs of immunized mice and control mice. However, mice immunized subcutaneously with either LPS or LPS-GBOMP vaccine showed significant protection against infection of the spleen (P< 0.001), liver (P< 0.001), and lungs (P< 0.05). These results show that intranasal immunization of mice with either vaccine provided significant protection against disseminated infection of the spleen and liver but subcutaneous immunization of mice with the vaccines conferred significant protection against infection of the spleen, liver, and lungs.

ABSTRACTHuman brucellosis can be acquired from infected animal tissues by ingestion, inhalation, or contamination of conjunctiva or traumatized skin by infected animal products. In addition, Brucellais recognized as a biowarfare threat agent. Although a vaccine to protect humans from natural or deliberate infection could be useful, vaccines presently used in animals are unsuitable for human use. We tested orally administered live, attenuated, purine auxotrophic B. melitensisWR201 bacteria for their ability to elicit cellular and humoral immune responses and to protect mice against intranasal challenge with B. melitensis16M bacteria. Immunized mice made serum antibody to lipopolysaccharide and non-O-polysaccharide antigens. Splenocytes from immunized animals released interleukin-2 and gamma interferon when grown in cultures with Brucellaantigens. Immunization led to protection from disseminated infection and enhanced clearance of the challenge inoculum from the lungs. Optimal protection required administration of live bacteria, was related to immunizing dose, and was enhanced by booster immunization. These results establish the usefulness of oral vaccination against respiratory challenge with virulent Brucellaand suggest that WR201 should be further investigated as a vaccine to prevent human brucellosis.

Intranasal immunization of mice with purified Brucella melitensis lipopolysaccharide (LPS) as a noncovalent complex with Neisseria meningitidis group B outer membrane protein (GBOMP) elicited a high-titer anti-LPS systemic antibody response and a significant mucosal antibody response. The anti-LPS immunoglobulin G (IgG) antibody was predominantly of the IgG1 subtype, although there was some response of the IgG2a, IgG2b, and IgG3 subtypes. The antibody titer remained high for 16 weeks postimmunization. Immunized mice and sham-immunized control mice were challenged intranasally with 10(4) CFU of virulent B. melitensis strain 16 M 4 weeks after the second dose of vaccine. The numbers of bacteria in lungs, livers, and spleens at 3 days, 9 days, and 8 weeks postchallenge were determined. Bacteria were found in lungs of all mice on day 3, but there was no disseminated infection of liver or spleen. By day 9, 40% of the mice had infected spleens and livers. At 8 weeks postchallenge, spleens of 25 of 62 immunized mice were infected, compared to 61 of 62 control mice (P < 0.0001). The livers of 12 of 43 immunized mice were infected, compared to 22 of 36 control mice (P = 0.005). In contrast, the lungs of 26 of 46 immunized mice were still infected, compared to 27 of 44 control mice. The numbers of bacterial CFU in lungs of immunized and control animals were identical. These studies show that intranasal immunization with B. melitensis LPS-GBOMP subunit vaccine significantly protects mice against intranasal challenge with virulent B. melitensis. Vaccination reduces bacterial dissemination to spleen and liver but has no effect on the course of lung infection.

ABSTRACTIntranasal immunization of mice with purified Brucella melitensislipopolysaccharide (LPS) as a noncovalent complex with Neisseria meningitidisgroup B outer membrane protein (GBOMP) elicited a high-titer anti-LPS systemic antibody response and a significant mucosal antibody response. The anti-LPS immunoglobulin G (IgG) antibody was predominantly of the IgG1 subtype, although there was some response of the IgG2a, IgG2b, and IgG3 subtypes. The antibody titer remained high for 16 weeks postimmunization. Immunized mice and sham-immunized control mice were challenged intranasally with 104CFU of virulent B. melitensisstrain 16 M 4 weeks after the second dose of vaccine. The numbers of bacteria in lungs, livers, and spleens at 3 days, 9 days, and 8 weeks postchallenge were determined. Bacteria were found in lungs of all mice on day 3, but there was no disseminated infection of liver or spleen. By day 9, 40% of the mice had infected spleens and livers. At 8 weeks postchallenge, spleens of 25 of 62 immunized mice were infected, compared to 61 of 62 control mice (P< 0.0001). The livers of 12 of 43 immunized mice were infected, compared to 22 of 36 control mice (P= 0.005). In contrast, the lungs of 26 of 46 immunized mice were still infected, compared to 27 of 44 control mice. The numbers of bacterial CFU in lungs of immunized and control animals were identical. These studies show that intranasal immunization with B. melitensisLPS-GBOMP subunit vaccine significantly protects mice against intranasal challenge with virulent B. melitensis.Vaccination reduces bacterial dissemination to spleen and liver but has no effect on the course of lung infection.

ABSTRACTAfter intranasal inoculation, Brucella melitensischronically infects the mononuclear phagocyte system in BALB/c mice, but it causes no apparent illness. Adaptive immunity, which can be transferred by either T cells or antibody from immune to naive animals, confers resistance to challenge infection. The role of innate, non-B-, non-T-cell-mediated immunity in control of murine brucellosis, however, is unknown. In the present study, we documented that BALB/c and C57BL/6 mice had a similar course of infection after intranasal administration of 16M, validating the usefulness of the model in the latter mouse strain. We then compared the course of infection in Rag1knockout mice (C57BL/6 background) (referred to here as RAG-1 mice) which have no B or T cells as a consequence of deletion ofRag1(recombination-activating gene 1), with infection in normal C57BL/6 animals after intranasal administration of B. melitensis16M. C57BL/6 mice cleared brucellae from their lungs by 8 to 12 weeks and controlled infection in the liver and spleen at a low level. In contrast, RAG-1 mice failed to reduce the number of bacteria in any of these organs. From 1 to 4 weeks after inoculation, the number of splenic bacteria increased from 2 to 4.5 logs and remained at that level. In contrast to the consistently high numbers of brucellae observed in the spleens, the number of bacteria rose in the livers sampled for up to 20 weeks. Immunohistologic examination at 8 weeks after infection disclosed foci of persistent pneumonia and large amounts of Brucellaantigen in macrophages in lung, liver, and spleen in RAG-1, but not C57BL/6, mice. These studies indicate that T- and B-cell-independent immunity can control Brucellainfection at a high level in the murine spleen, but not in the liver. Immunity mediated by T and/or B cells is required for clearance of bacteria from spleen and lung and for control of bacterial replication in the liver.

ABSTRACTHuman brucellosis can be acquired from infected animal tissues by ingestion, inhalation, or contamination of the conjunctiva or traumatized skin by infected animal products. A vaccine to protect humans from occupational exposure or from zoonotic infection in areas where the disease is endemic would reduce an important cause of morbidity worldwide. Vaccines currently used in animals are unsuitable for human use. We tested a live, attenuated, purine-auxotrophic mutant strain of Brucella melitensis, WR201, for its ability to elicit cellular and humoral immune responses and to protect mice against intranasal challenge with B. melitensis16M. Mice inoculated intraperitoneally with WR201 made serum antibody to lipopolysaccharide and non-O-polysaccharide antigens. Splenocytes from immunized animals released interleukin-2 (IL-2), gamma interferon, and IL-10 when cultured with Brucellaantigens. Immunization led to protection from disseminated infection but had only a slight effect on clearance of the challenge inoculum from the lungs. These studies suggest that WR201 should be further investigated as a vaccine to prevent human brucellosis.