Regulation of Escherichia coli fim gene transcription by GadE and other acid tolerance gene products.

Uropathogenic Escherichia coli (UPEC) cause millions of urinary tract infections each year in the United States. Type 1 pili are important for adherence of UPEC to uroepithelial cells in the human and murine urinary tracts where osmolality and pH vary. Previous work has shown that an acidic pH adversely affects the expression of type 1 pili. To determine if acid tolerance gene products may be regulating E. coli fim gene expression, a bank of K-12 strain acid tolerance gene mutants were screened using fimA-lux, fimB-lux, and fimE-lux fusions on single copy number plasmids. We have determined that a mutation in gadE increased transcription of all three fim genes, suggesting that GadE may be acting as a repressor in a low pH environment. Complementation of the gadE mutation restored fim gene transcription to wild-type levels. Moreover, mutations in gadX, gadW, crp, and cya also affected transcription of the three fim genes. To verify the role GadE plays in type 1 pilus expression, the NU149 gadE UPEC strain was tested. The gadE mutant had higher fimE gene transcript levels, a higher frequency of Phase-OFF positioning of fimS, and hemagglutination titres that were lower in strain NU149 gadE cultured in low pH medium as compared to the wild-type bacteria. The data demonstrate that UPEC fim genes are regulated directly or indirectly by the GadE protein and this could have some future bearing on the ability to prevent urinary tract infections by acidifying the urine and shutting off fim gene expression.

Emerging connections between gut microbiome bioenergetics and chronic metabolic diseases.

The conventional viewpoint of single-celled microbial metabolism fails to adequately depict energy flow at the systems level in host-adapted microbial communities. Emerging paradigms instead support that distinct microbiomes develop interconnected and interdependent electron transport chains that rely on cooperative production and sharing of bioenergetic machinery (i.e., directly involved in generating ATP) in the extracellular space. These communal resources represent an important subset of the microbial metabolome, designated here as the "pantryome" (i.e., pantry or external storage compartment), that critically supports microbiome function and can exert multifunctional effects on host physiology. We review these interactions as they relate to human health by detailing the genomic-based sharing potential of gut-derived bacterial and archaeal reference strains. Aromatic amino acids, metabolic cofactors (B vitamins), menaquinones (vitamin K2), hemes, and short-chain fatty acids (with specific emphasis on acetate as a central regulator of symbiosis) are discussed in depth regarding their role in microbiome-related metabolic diseases.

Potential Role of Extracellular ATP Released by Bacteria in Bladder Infection and Contractility.

Urgency urinary incontinence (UUI) and overactive bladder (OAB) can both potentially be influenced by commensal and urinary tract infection-associated bacteria. The sensing of bladder filling involves interplay between various components of the nervous system, eventually resulting in contraction of the detrusor muscle during micturition. This study models host responses to various urogenital bacteria, first by using urothelial bladder cell lines and then with myofibroblast contraction assays. To measure responses, we examined Ca2+ influx, gene expression, and alpha smooth muscle actin deposition assays. Organisms such as Escherichia coli and Gardnerella vaginalis were found to strongly induce Ca2+ influx and contraction, whereas Lactobacillus crispatus and L. gasseri did not induce this response. Additionally, supernatants from lactobacilli impeded Ca2+ influx and contraction induced by uropathogens. Upon further investigation of factors associated with purinergic signaling pathways, the Ca2+ influx and contraction of cells correlated with the amount of extracellular ATP produced by E. coli Certain lactobacilli appear to mitigate this response by utilizing extracellular ATP or producing inhibitory compounds that may act as a receptor agonist or Ca2+ channel blocker. These findings suggest that members of the urinary microbiota may be influencing UUI or OAB.IMPORTANCE The ability of uropathogenic bacteria to release excitatory compounds, such as ATP, may act as a virulence factor to stimulate signaling pathways that could have profound effects on the urothelium, perhaps extending to the vagina. This may be countered by the ability of certain commensal urinary microbiota constituents, such as lactobacilli. Further understanding of these interactions is important for the treatment and prevention of UUI and OAB. The clinical implications may require a more targeted approach to enhance the commensal bacteria and reduce ATP release by pathogens.

Draft Genome Sequence of Escherichia coli K-12 (ATCC 10798).

Here, we present the draft genome sequence of Escherichia coli ATCC 10798. E. coli ATCC 10798 is a K-12 strain, one of the most well-studied model microorganisms. The size of the genome was 4,685,496 bp, with a G+C content of 50.70%. This assembly consists of 62 contigs and the F plasmid.

Draft Genome Sequence of Escherichia coli K-12 (ATCC 29425).

A draft genome sequence for Escherichia coli ATCC 29425 was investigated. The size of the genome was 4,608,319 bp, with an observed G+C content of 50.68%. This assembly consisted of 80 contigs, with an average coverage of 122.2×, including one contig representative of the complete genome for the temperate phage P1.

Draft Genome Sequence of Micrococcus luteus (Schroeter) Cohn (ATCC 12698).

The actinobacterium Micrococcus luteus can be found in a wide variety of habitats. Here, we report the 2,411,958-bp draft genome sequence of the type strain M. leuteus (Schroeter) Cohn (ATCC 12698). Characteristic of this taxa, the genome sequence has a high G+C content, 73.14%.

Draft Genome Sequence of Enterococcus faecalis ATCC BAA-2128.

While a part of the native gut microflora, the Gram-positive bacterium Enterococcus faecalis can lead to serious infections elsewhere in the body. The draft genome of E. faecalis strain ATCC BAA-2128, isolated from piglet feces, was examined. This draft genome consists of 42 contigs, 12 of which exhibit homology to annotated plasmids.

Draft Genome Sequences of Two ATCC Staphylococcus aureus subsp. aureus Strains.

Draft genome sequences for Staphylococcus aureus subsp. aureus Rosenbach ATCC 14458 and ATCC 27217 strains were investigated. The genome sizes were 2,880,761 bp and 2,759,100 bp, respectively. Strain ATCC 14458 was assembled into 39 contigs, including 3 plasmids, and strain ATCC 27217 was assembled into 25 contigs, including 2 plasmids.

Draft Genome Sequence of Staphylococcus epidermidis (Winslow and Winslow) Evans (ATCC 14990).

Here, we report the draft genome sequence for the type strain Staphylococcus epidermidis (Winslow and Winslow) Evans (ATCC 14990). The assembly consisted of 2,457,519 bp with an observed G+C content of 32.04%. Thirty-seven contigs were produced, including two putative plasmids, with a 296.8× coverage and an N50 of 180,848 bp.

Decreased activity of commercially available disinfectants containing quaternary ammonium compounds when exposed to cotton towels.

BACKGROUND: Health care-associated infections (HAIs) are a significant problem in hospitals, and environmental surfaces have been implicated as a source of HAIs in the hospital environment. Furthermore, Gram-negative and Gram-positive bacteria can persist on dry environmental surfaces for as long as several months. Poorly cleaned surfaces may serve as vehicles for microbes, which may then be transferred to patients. METHODS: Cotton and microfiber towels were both tested for their abilities to bind quaternary ammonium compounds (QACs). The towels were exposed to 3 commercially available disinfectants for 0.5, 30, and 180 minutes. Germicidal spray tests (GSTs) were performed for all towel eluates in accordance with the AOAC International method 961.02. Cotton towel eluates were analyzed for QAC concentration using high-performance liquid chromatography. RESULTS: QAC concentrations were reduced by up to 85.3% after exposure to cotton towels, resulting in failure of the disinfectants exposed to cotton towels in 96% of the GSTs. CONCLUSION: The use of cotton towels with QAC-based cleansers should be reconsidered, particularly in hospitals where effective cleaning of the patient environment is needed to reduce the risk of HAIs.

Microbial contamination of hospital reusable cleaning towels.

BACKGROUND: Hospital cleaning practices are critical to the prevention of nosocomial infection transmission. To this end, cloth towels soaked in disinfectants are commonly used to clean and disinfect hospital surfaces. Cloth cleaning towels have been linked to an outbreak of Bacillus cereus and have been shown to reduce the effectiveness of commonly used quaternary ammonium disinfectants. Thus, it is important to determine whether the reuse of cloth towels increases the risk of pathogen transmission in hospitals. METHODS: The goal of this project was to determine the effects of laundry and cleaning practices commonly used in hospitals for washing, storage, and disinfection of cloth cleaning towels on their microbial loads. RESULTS: Our results indicate that cloth towels used for cleaning hospital rooms contained high numbers of microbial contaminants. CONCLUSIONS: In this case, hospital laundering practices appear insufficient to remove microbial contaminants and may even add contaminants to the towels. Furthermore, it has been previously reported that towels can interfere with the action of common hospital disinfectants. Either independently or in combination, these 2 factors may increase the risk for transmission of pathogens in hospitals. These observations indicate the need to critically reevaluate current hospital cleaning practices associated with reuse of cloth towels.

Screening a mushroom extract library for activity against Acinetobacter baumannii and Burkholderia cepacia and the identification of a compound with anti-Burkholderia activity.

BACKGROUND: Acinetobacter baumannii and species within the Burkholderia cepacia complex (BCC) are significant opportunistic bacterial pathogens of humans. These species exhibit a high degree of antibiotic resistance, and some clinical isolates are resistant to all currently available antimicrobial drugs used for treatment. Thus, new drugs are needed to treat infections by these species. Mushrooms could be a potential source for new drugs to treat A. baumannii and BCC infections. METHODS: The aim of this study was to screen a library of crude extracts from 330 wild mushrooms by disk diffusion assays for antibacterial activity against A. baumannii and Burkholderia cepacia in the hope of identifying a novel natural drug that could be used to treat infections caused by these species. Once positive hits were identified, the extracts were subjected to bioassay-guided separations to isolate and identify the active drug molecules. MICs were performed to gauge the in vitro activity of the purified compounds. RESULTS: Only three crude extracts (0.9%) had activity against A. baumannii and B. cepacia. Compounds from two of these extracts had MICs greater than 128 microg/ml, and further analyses were not performed. From the third extract, prepared from Leucopaxillus albissimus, 2-aminoquinoline (2-AQ) was isolated. This compound exhibited a modest MIC in vitro against strains from nine different BCC species, including multi-drug resistant clinical isolates (MIC = 8-64 microg/ml), and a weak MIC (128 microg/ml) against A baumannii. The IC50 against a murine monocyte line was 1.5 mg/ml. CONCLUSION: The small number of positive hits in this study suggests that finding a new drug from mushrooms to treat Gram-negative bacterial infections may be difficult. Although 2-AQ was identified in one mushroom, and it was shown to inhibit the growth of multi-drug resistant BCC isolates, the relatively high MICs (8-128 microg/ml) for both A. baumannii and BCC strains suggests that 2-AQ is not suitable for further drug development in its current form.

New classes of Gram-positive selective antibacterials: inhibitors of MRSA and surrogates of the causative agents of anthrax and tuberculosis.

An antimicrobial phenolic stilbene, (E)-3-hydroxy-5-methoxystilbene, 1 was recently isolated from the leaves of Comptonia peregrina (L.) Coulter and shown to possess inhibitory activity against several Gram-positive bacteria, including isolates of methicillin-resistant Staphylococcus aureus (MRSA), Mycobacterium bovis BCG, and avirulent Bacillusanthracis (Sterne strain), among others. These results prompted the design and synthesis of two new classes of compounds, phenoxystyrenes and phenothiostyrenes, as analogs of the natural antimicrobial stilbene. These and additional stilbenoid analogs were synthesized using new, efficient, copper-mediated coupling strategies. Minimum inhibitory concentration (MIC) antimicrobial assays were performed on all compounds prepared. These preliminary structure-activity relationship studies indicated that both new classes of synthetic analogs, as well as the stilbenes, show promising activity against Gram-positive bacteria when at least one phenolic moiety is present, but not when absent. The potencies of the phenolic phenoxystyrenes and phenothiostyrenes were found to be comparable to those of the phenolic stilbenes tested.