Efficacy Bacteriophage in Removal Pseudomonas aeruginosa from Infectious Surfaces

Nosocomial infections can be transmitted by contaminated hospital surfaces with resistant pathogens. conventional sanitations are not efficiently contributing to removing resistant pathogens. Bacteriophages suggest as decontaminating agents, safe, their selective ability to kill specific bacteria. This work aimed to assess the efficiency of a phage in removing Pseudomonas aeruginosa from different hard surfaces. The decontamination ability of phages w was tested in vitro against Pseudomonas aeruginosa strain. Cystoviridae Phages with titer (2 × 1012 PFU/mL) can efficiently reduce viable bacterial cells on contaminated surfaces. The treated surfaces with alcohol 70% and phage showed an evident drop of bacterial cell number from 1 h to 24 h. These results suggest that bacteriophages are biocontrol agents removing nosocomial infection pathogens transmitted by contaminated surfaces in the hospital environment.

Consideration of Influential Factors on Bioleaching of Gold Ore Using Iodide-Oxidizing Bacteria

Iodide-oxidizing bacteria (IOB) oxidize iodide into iodine and triiodide which can be utilized for gold dissolution. IOB can be therefore useful for gold leaching. This study examined the impact of incubation conditions such as concentration of the nutrient and iodide, initial bacterial cell number, incubation temperature, and shaking condition on the performance of the gold dissolution through the experiments incubating IOB in the culture medium containing the marine broth, potassium iodide and gold ore. The minimum necessary concentration of marine broth and potassium iodide for the complete gold dissolution were determined to be 18.7 g/L and 10.9 g/L respectively. The initial bacterial cell number had no effect on gold dissolution when it was 1 × 104 cells/mL or higher. Gold leaching with IOB should be operated under a temperature range of 30–35 °C, which was the optimal temperature range for IOB. The bacterial growth rate under shaking conditions was three times faster than that under static conditions. Shaking incubation effectively shortened the contact time compared to the static incubation. According to the pH and redox potential of the culture solution, the stable gold complex in the culture solution of this study could be designated as gold (I) diiodide.

Optimization of the fermentation time and bacteria cell concentration in the starter culture for cyanide acid removal from wild cassava (Manihot glaziovii)

Cassava is one of the most widespread starchy tuberous roots in Indonesia, being one of the typical plants used in the starch market. However, due to the high cyanide content (338.41 ppm), these roots become a poison if they are unsuitably processed. Therefore, a detoxification process is needed to reduce the cyanide level to the safe level for human consumption (10 ppm). This study was focused on (i) the investigation of the detoxification potential of fermentation with Lactobacillus plantarum (L. plantarum) on the cyanide level of wild cassava tubers (Manihot glaziovii) and (ii) the optimization of the fermentation time and bacteria cell number in the starter culture. The fermentation was performed for different periods of time (12, 24 and 36 h) and various initial bacteria cell number (7x1010, 7x1011, 1.05x1012, and 3.5x1012 L. plantarum cells). The results showed a significant decrease of the cyanide level, 97 % of cyanide degradation being noticed after 36 h of fermentation for an initial bacterial cell number of 3.5x1012 cells. Hence, the strong point of the study consists of a noteworthy reduction of the cyanide content in wild cassava in short periods, whereas the protein content was increased (from 1.5% to 3.5%) in Modified Cassava Flour (MOCAF).

Characterization of aStaphylococcus aureusSurface Virulence Factor That Promotes Resistance to Oxidative Killing and Infectious Endocarditis

ABSTRACTStaphylococcus aureusis a prominent human pathogen and a leading cause of community- and hospital-acquired bacterial infections worldwide. Herein, we describe the identification and characterization of theS. aureus67.6-kDa hypothetical protein, named for thesurface factor promoting resistance tooxidativekilling (SOK) in this study. Sequence analysis showed that the SOK gene is conserved in all sequencedS. aureusstrains and homologous to the myosin cross-reactive antigen ofStreptococcus pyogenes.Immunoblotting and immunofluorescence analysis showed that SOK was copurified with membrane fractions and was exposed on the surface ofS. aureusNewman and RN4220. Comparative analysis of wild-typeS. aureusand an isogenic deletion strain indicated that SOK contributes to both resistance to killing by human neutrophils and to oxidative stress. In addition, theS. aureus sokdeletion strain showed dramatically reduced aortic valve vegetation and bacterial cell number in a rabbit endocarditis model. These results, plus the suspected role of the streptococcal homologue in certain diseases such as acute rheumatic fever, suggest that SOK plays an important role in cardiovascular and other staphylococcal infections.

Antibacterial activity of the seminal plasma of Paracentrotus lividus

Seminal plasma from Paracentrotus lividus exerted an inhibitory action on the growth of bacterial colonies. The antibacterial reaction took 30 min to reach full expression and depended on both the dose of seminal plasma and the bacterial cell number. Heating at 56 °C for 60 min did not lower the antibacterial power of the seminal plasma. Morphological examination of bacteria treated with seminal plasma revealed a conspicuous alteration of their surface and suggested a lytic mode of action for the antibacterial factor(s). Lysozyme could be involved in this process. In fact, inhibition of bacterial growth strongly decreased when this hydrolase was inactivated by heating at a basic pH.