Bacterial infection is a leading cause of morbidity and mortality arising from platelet transfusions (1, 2). Storage of platelet products at room temperature (20 to 24ºC) provides ideal conditions for bacterial proliferation (1, 3-6). Furthermore, platelets are stored in plasma containing bioavailable iron that bacteria require to survive (7). Thus we hypothesize that the inclusion of iron chelators will bind and remove iron, thereby inhibiting bacterial growth in both culture medium and platelet concentrates. Additionally, we hypothesize that residual red blood cells (RBCs) in platelet units may contribute bioavailable iron that promotes bacterial growth. To test these hypotheses, we first assessed growth of Staphylococcus epidermidis in culture medium after treatment with the iron chelators deferoxamine (DFO) or phytic acid. DFO significantly inhibited bacterial growth in a dose dependent manner (p < 0.009). Conversely, phytate only inhibited bacterial growth at concentrations ≥ 100 mM (p < 0.001); at ≤ 5 mM, phytate supplied S. epidermidis with additional nutrients and significantly promoted growth (p < 0.001). Subsequently, we monitored the change in RBCs over time. Hemolysis, methemoglobin, and iron levels all significantly increased over the 7-day storage period (p < 0.001) releasing bioavailable iron. Indeed, we found that S. epidermidis growth in iron-poor medium drastically increased with the addition of RBCs, thus supporting our second hypothesis. Surprisingly, the inclusion of DFO in minimal medium did not demonstrate a bacteriostatic effect in the presence of RBCs. The inhibitory effect of DFO was likely overcome by iron released from the elevated methemoglobin levels arising from the direct interaction of DFO with hemoglobin. Previous studies demonstrate that methemoglobin releases iron more quickly than normal hemoglobin (8). Lastly, we evaluated the effect of DFO on microbial growth in platelet concentrates using the BacT/ALERT system. The presence of DFO significantly inhibited S. epidermidis growth in buffy coat platelets in a dose dependent manner (p < 0.001). With these findings, the inclusion of iron chelators is a promising approach to preventing transfusion-transmitted bacterial infection and providing patients with a safer platelet product.

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The land application of poultry litter as a fertilizer is a common practice due to the low cost and high availability of poultry litter in some regions. However, land application can create concerns related to runoff water quality and odor. An experiment was conducted to determine the effectiveness of in-house windrow composting (IWC) of poultry litter prior to land application in terms of bacteria, odors and nutrients compared to untreated (fresh) litter. In the second part of the research, the objective was to quantify the number and distribution within poultry houses of selected water quality indicator bacteria in litter. Comparison of fresh and IWC litter showed that Escherichia coli (E. coli) was present in very low concentrations on day 1 in fresh litter (20 cfu/g) and IWC litter (55 cfu/g), but the levels were undetectable in both litter types on day 9 in Trial 1. In Trial 2, E. coli levels were undetectable in IWC litter before and after the IWC process. Similarly, fresh litter had undetectable E. coli levels on day 1, but 185 cfu/g on day 10. Additionally, nutrient analysis and moisture content results showed no significant differences between fresh and IWC litter. To evaluate odor differences between fresh and IWC litter, volatile gases were collected onto sorbent tubes and into Tedlar bags from wind tunnel flux chambers placed directly on litter piles prior to land application. The concentrations of 13 compounds commonly associated with animal manure were then determined by GC/MS. Analysis of volatile gas samples resulted in significant changes of various individual odorants, while olfactometry analysis of Tedlar bag air samples resulted in reduced detection threshold values for IWC litter compared to the fresh litter. These results indicate the possible mitigating effects IWC may have on odors associated with litter. In the survey of bacterial distribution within poultry houses, litter counts varied greatly within house sections and between farms. Regression analysis revealed that bacterial counts and litter moisture content are significantly related, thus explaining much of the variation in litter bacterial counts within a house. These results indicate that IWC could be a useful best management practice to reduce E. coli levels and odor associated with poultry litter prior to land application, but factors such as moisture content, initial bacteria concentrations, and windrow size all affect the level of bacteria and odor reduction.

Anaerobes belonging to the genera Propionibacterium, Bacteroides, Peptococcus, Peptostreptococcus, Eubacterium, Streptococcus and Lactobacillus, which are commonly isolated from the human urogenital flora, were tested for their ability to inhibit the in vitro growth of Neisseria gonorrhoeae strains. / The antigonococcal effect of the anaerobic bacterial strains tested was found not to be due to nutrient depletion and pH change of the media which had supported their growth. This inhibition was not an all-or-none phenomenon since an inhibitory strain did not necessarily interfere with all the gonococcal strains tested. / All the 23 lactobacilli strains tested were found to inhibit the in vitro growth of N. gonorrhoeae. This inhibition was found to be dependent on the composition of the culture medium. In comparison to the gonococcus (GC) and dextrose starch agar (DSA) media, a modified deMan, Rogosa et Sharpe (MRS) medium was more appropriate to support both the growth of lactobacilli and the production of their antigonococcal activity. / For the other 32 anaerobic bacterial strains tested, six were selected for their large antigonococcal spectrum of activity. These strains were Peptostreptococcus anaerobius (Pc9,Ps11B,Ps11C), Bacteroides fragilis (B1A), Bacteroides ovatus (B24) and Eubacterium limosum (Ps11A). The antigonococcal activity produced by these six strains appeared to be specific to the gonococcus since a variety of anaerobes and aerobes were not generally inhibited. / E. limosum and B. fragilis strains were further selected to evaluate the production of their antigonococcal activity in liquid medium. E. limosum Ps11A strain produced its inhibitory activity in prereduced brain heart infusion (BHI) broth during the mid-logarithmic phase of growth, when no inhibitory concentration of short-chain fatty acids was detected in the culture medium. Furthermore, when the amounts of short-chain fatty acids produced by E. limosum increased, its antigonococcal activity decreased. Based on these results and on the individual amount of short-chain fatty acids excreted by E. limosum strains, it was concluded that the observed antigonococcal activity was not due to the presence of these acids. However, B. fragilis strains excreted propionic acid in amount reported to be inhibitory to the gonococcus. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI

Microbial metabolic activity in the hypolimnia and sediments of lakes drives the recycling of organic matter both through mineralization and the production of microbial biomass, which may be utilized by grazers. A correction factor was developed based on the water content of sediment samples that corrects sediment bacteria microscopic counts for masking due to sediment particles. Using this correction factor, it was found that sediment bacterial biomass in 22 lakes was positively related to an indicator of the rate of allochthonous organic matter input to lakes. However, the total hypolimnetic carbon mineralization rate of lakes, which integrates both sediment and hypolimnetic water column mineralization, was found to be driven mainly by phytoplankton carbon and to occur mainly in the hypolimnetic water column. Indeed, various hypolimnetic and sediment catabolic processes were found to show a strong positive relationship with indicators of autochthonous organic matter standing stocks and production. In no cases were the processes significantly positively correlated with allochthonous organic matter standing stocks. Results of this research show that autochthonous primary production drives carbon recycling in the hypolimnetic water column, with the ultimate fate of this production being determined principally by the hypolimnetic thickness. The main fate of allochthonous organic matter in lakes is to become a major component of sediment organic matter where it likely drives a much slower catabolism due to its recalcitrance.

Amino acid and potassium transport were studied in Alteromonas haloplanktis, strain 214, variant 3 (ATCC 19855). Stationary phase cells exhibited greater transport activity for AIB and K('+) than mid-logarithmic phase cells. Transport activity for amino acids in membrane vesicles was less than 1% of that in intact cells regardless of the method employed to form vesicles. French press disruption of protoplasts gave vesicle preparations with the greatest capacity for amino acid transport. Greater than 85% of the population of membrane vesicles in these preparations was oriented right-side-out as judged by freeze-etch electron microscopy. A membrane-bound, Mg('2+)-stimulated ATPase activity was present in vesicle preparations. Expression of this activity required disruption of the membrane vesicles, indicating its localisation on the inner surface of the vesicle membrane. This is further evidence that the vesicles are oriented right-side-out. K('+) transport was studied in K('+)-depleted cells by a K('+) ion-specific electrode technique. K('+) uptake was shown to be a strictly aerobic process and was concurrent with H('+) efflux. K('+) uptake occurs in response to a membrane potential and is not dependent on ATP. The membrane potential in whole cells was estimated from the K('+) distribution as -151mv. In vesicle preparations, (DELTA)(psi) was estimated by the distribution of ('3)H-TPMP('+) as -87mv. The failure of membrane vesicles to accumulate K('+) may be due to the low membrane potential that is generated in vesicle preparations.

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