Neomycin/Polymyxin B/Bacitracin Zinc

2020 ◽  
Author(s):  
Keyword(s):  
Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.


2007 ◽  
Vol 20 (11) ◽  
pp. 1421-1430 ◽  
Author(s):  
Christian Sohlenkamp ◽  
Kanaan A. Galindo-Lagunas ◽  
Ziqiang Guan ◽  
Pablo Vinuesa ◽  
Sally Robinson ◽  
...  

Lysyl-phosphatidylglycerol (LPG) is a well-known membrane lipid in several gram-positive bacteria but is almost unheard of in gram-negative bacteria. In Staphylococcus aureus, the gene product of mprF is responsible for LPG formation. Low pH-inducible genes, termed lpiA, have been identified in the gram-negative α-proteobacteria Rhizobium tropici and Sinorhizobium medicae in screens for acid-sensitive mutants and they encode homologs of MprF. An analysis of the sequenced bacterial genomes reveals that genes coding for homologs of MprF from S. aureus are present in several classes of organisms throughout the bacterial kingdom. In this study, we show that the expression of lpiA from R. tropici in the heterologous hosts Escherichia coli and Sinorhizobium meliloti causes formation of LPG. A wild-type strain of R. tropici forms LPG (about 1% of the total lipids) when the cells are grown in minimal medium at pH 4.5 but not when grown in minimal medium at neutral pH or in complex tryptone yeast (TY) medium at either pH. LPG biosynthesis does not occur when lpiA is deleted and is restored upon complementation of lpiA-deficient mutants with a functional copy of the lpiA gene. When grown in the low-pH medium, lpiA-deficient rhizobial mutants are over four times more susceptible to the cationic peptide polymyxin B than the wild type.


2021 ◽  
pp. 1-6
Author(s):  
Kenji Fujimori ◽  
Kunio Tarasawa ◽  
Kiyohide Fushimi

<b><i>Introduction:</i></b> Polymyxin B hemoperfusion (PMX) reduces endotoxin in septic shock patients’ blood and can improve hemodynamics and organ functions. However, its effects on the reduction of septic shock mortality are controversial. <b><i>Methods:</i></b> Using the Japanese diagnosis procedure combination database from April 2016 to March 2019, we identified adult septic shock patients treated with noradrenaline. This study used propensity score matching to compare the outcome between PMX-treated and non-treated patients. The primary endpoint was 28-day mortality, counting from the day of noradrenaline initiation. The secondary endpoints were noradrenaline-, ventilator-, and continuous hemodiafiltration (CHDF)-free days at day 28. <b><i>Results:</i></b> Of 30,731 eligible patients, 4,766 received PMX. Propensity score matching produced a matched cohort of 4,141 pairs with well-balanced patient backgrounds. The 28-day survival rate was 77.9% in the PMX group and 71.1% in the control group (<i>p</i> &#x3c; 0.0001). Median days of noradrenalin-, CHDF-, and ventilator-free days were 2 days (<i>p</i> &#x3c; 0.0001), 2 days (<i>p</i> &#x3c; 0.0001), and 6 days (<i>p</i> &#x3c; 0.0001) longer in the PMX group than in the control group, respectively. When stratified with the maximum daily dose of noradrenaline, the PMX group showed a statistically significant survival benefit in the groups with noradrenaline dose &#x3c;20 mg/day but not in the noradrenaline group dose ≥20 mg/day. <b><i>Conclusion:</i></b> Analysis of large Japanese databases showed that septic shock patients who received noradrenaline might benefit from PMX treatment.


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