The effect of cultural conditions on cell surface hydrophobicity of Candida albicans and Candida glabrata was tested. C. albicans cells grown at room temperature were more hydrophobic than cells grown at 37°C. No consistent pattern was observed with C. glabrata. Relative hydrophobicity was found to vary with the growth phase and growth medium for both species. The implications for pathogenesis studies are discussed.

The ability to affect eukaryotic and prokaryotic cellular growth, signaling and differentiation is a continuing focus in the pharmaceutical industry. The fundamental ability to affect these cellular processes is inherent in lactones. Lactones, which are ubiquitous in nature, reflect a broad phylogenetic diversity indicative of their ability to act as simple alkylating compounds, with their in situ activities falling into one of two categories, i.e., protect or conquer. Medically, their utility as pharmaceutical agents range from that of antimicrobial to anti-neoplastic agent depending on the functional groups attached.

The ability of insulin to affect the growth kinetics of Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, and Pseudomonas aeruginosa was measured. For all organisms, insulin, in the absence of a metabolizable sugar source, i.e., glucose or starch in Mueller-Hinton medium, had no effect on generation time as compared with a homologous control. Response to insulin, in the form of increased or decreased generation times, for both Gram-positive and Gram-negative bacteria, was dependent on the concentration of insulin, the concentration of glucose present, and the initial concentration of bacteria exposed to the glucose and insulin.

The effects of androgens, testosterone and dihydrotestosterone (DHT), of an environmental anti-androgen, 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene (DDE), and of glucocorticoids, hydrocortisone and dexamethasone, on growth kinetics and antibiotic susceptibility of E. faecalis, E. coli, P. aeurginosa, and S. aureus were measured. For P. aeurginosa, the presence of either DHT or DDE caused at least a fourfold shift in the minimum inhibitory concentration (MIC) of cefepime and tobramycin. DHT and DDE also affected the response of E. faecalis to meropenem and norfloxacin, resulting in a shift from sensitive to intermediate resistance (four-fold increase in MIC). Hydrocortisone (2 microM) induced an increase in the sensitivity of S. aureus to erythromycin, as compared to hormone-free control (from 0.5 to 0.06 microg/mL). The susceptibility pattern of E. coli was unaffected by the hormones tested. These changes in susceptibility to antibiotics were unrelated to alterations in growth kinetics. For all organisms tested, the alterations in MICs occurred only in the presence of hormone, indicative of changes in the phenotype of these stable quality control strains.

No abstract

Kratom (Mitragyna speciosa, Korth) is a tree-like plant that is indigenous to Southeast Asia. Kratom leaf products have been used in traditional folk medicine for their unique combination of stimulant and opioid-like effects. Kratom is being increasingly used in the West for its reputed benefits in the treatment of pain, depression and opioid use disorder. Recently, the United States Food and Drug Administration and Centers for Disease Control have raised concerns regarding the contamination of some kratom products with toxic metals (Pb and Ni) and microbes such as Salmonella. To further explore this issue, eight different kratom products were legally purchased from various “head”/”smoke” shops in the Western Suburbs of Chicago and then tested for microbial burden, a panel of metals (Ni, Pb, Cr, As, Hg, Cd), and levels of the main psychoactive alkaloid mitragynine. All of the samples contained significant, but variable, levels of mitragynine (3.9–62.1 mg/g), indicating that the products were, in fact, derived from kratom. All but two of the samples tested positive for the presence of various microbes including bacteria and fungi. However, none of the samples tested positive for Salmonella. Seven products showed significant levels of Ni (0.73–7.4 µg/g), Pb (0.16–1.6 µg/g) and Cr (0.21–5.7 µg/g) while the other product was negative for metals. These data indicate that many kratom products contain variable levels of mitragynine and can contain significant levels of toxic metals and microbes. These findings highlight the need for more stringent standards for the production and sale of kratom products.

The effect of D-mannose and D-glucose on bacteriuria due to Escherichia coli with mannose-sensitive adhesins was investigated in adult male Sprague-Dawley rats undergoing diuresis. Inocula of 10(5), 10(7), or 10(8) bacteria in 0.1 ml of normal saline or 2.5% or 10% D-mannose or D-glucose were injected intravesically and urine was cultured 1, 3, 5, 7 and 9 days later. The levels of bacteriuria on days 1 and 5 were significantly lower in rats inoculated with 10(5) E coli and 10% D-mannose than in controls (p less than 0.05 and 0.01 respectively) and the percentages of rats with less than 100 bacteria/ml were higher on days 1 and 3 (p = 0.05 and 0.02 respectively). Bacteriuria was significantly lower in rats inoculated with 10(7) bacteria and 10% D-mannose than in controls on days 5 and 7 (p less than 0.01 for each day) and the percentage of rats with less than 100 bacteria/ml was higher on day 7 (p = 0.01). D-glucose reduced bacteriuria significantly only with a concentration of 10% after instillation of 10(5) E. coli (p less than 0.05, day 1). The results indicate that D-mannose and D-glucose can significantly reduce bacteriuria within 1 day and that their efficacy is dependent upon the concentration of both saccharide and bacteria.

Although herpes simplex virus type-1 (HSV-1), and type-2 (HSV-2), Staphylococcus aureus and Candida albicans co-habit the oral and genital mucosa, their interaction is poorly understood. We determined the effect HSV has on bacterial and/or fungal adherence, the initial step in biofilm formation. HeLa229 cells were infected with HSV-1 (KOS) gL86 or HSV-2 (KOS) 333gJ 2 at a multiplicity of infection (MOI) of 50 and 10. S. aureus (ATCC 25923) and/or C. albicans (yeast forms or germ tube forms) were co-incubated for 30 min (37°C; 5 % CO 2 ; 5:1 organism: HeLa cell ratio; n = 16) with virus-infected HeLa cells or uninfected HeLa cell controls. Post-incubation, the monolayers were washed (3x; PBS), lysed (RIPA), and the lysate plated onto Fungisel and/or mannitol salts agar for standard colony count. The level of HeLa-associated S. aureus was significantly decreased (P \ 0.05) for both HSV-1-and HSV-2-infected cells, as compared to virus-free HeLa cell controls (38 and 59 % of control, respectively). In contrast, HSV-1 and HSV-2 significantly (P \ 0.05) enhanced HeLa cell association of C. albicans yeast forms and germ tube approximately two-fold, respectively. The effect of S. aureus on germ tube and yeast form adherence to HSV-1-and HSV-2-infected cells was specific for the Candida phenotype tested. Our study suggests that HSV, while antagonist towards S. aureus adherence enhances Candida adherence. Furthermore, the combination of the three pathogens results in S. aureus adherence that is either unaffected, or partially restored depending on both the herpes viral species and the fungal phenotype present.