PLB-985 Neutrophil-Like Cells as a Model To Study Aspergillus fumigatus Pathogenesis

Polymorphonuclear leukocytes are an important defense against human fungal pathogens, yet our model systems to study this group of cells remain very limited in scope. In this study, we established that differentiated PLB-985 cells can serve as a model to recapitulate several important aspects of human polymorphonuclear leukocyte interactions with the important human fungal pathogen Aspergillus fumigatus .

Streptococcus gordonii DL1 evades polymorphonuclear leukocyte-mediated killing via resistance to lysozyme

Streptococcus gordonii is an etiological bacterial agent of infective endocarditis. Although the pathogenesis mechanisms are not well understood, the interaction between streptococci and phagocytes is considered important for the development of infective endocarditis. Previous studies show that some S. gordonii strains, including DL1, survive in polymorphonuclear leukocytes (PMNs), whereas other strains such as SK12 are sensitive to PMN-dependent killing. In this study, we assessed the differences between the sensitivity of S. gordonii DL1 and S. gordonii SK12 to PMN-dependent killing. S. gordonii DL1 showed a higher survival when treated with PMNs than SK12. Both S. gordonii DL1 and S. gordonii SK12 showed high resistance to low pH condition. Compared to S. gordonii SK12, S. gordonii DL1 was sensitive to hydrogen peroxide. However, the resistance of S. gordonii DL1 to the tested bactericidal agents, especially lysozyme, was higher than that of SK12. Furthermore, we performed a bactericidal assay by treating a mixture of S. gordonii DL1 and SK12 with PMNs. S. gordonii DL1 did not enhance the survival of S. gordonii SK12 exposed to PMNs. These results indicated that S. gordonii DL1 is resistant to bactericidal agents that degrade bacteria in phagolysosomes. In addition, there was no secretory factor involved in the resistance to bactericidal agents. The findings of this study may help develop treatments for infective endocarditis caused by S. gordonii.

Prophylactic use of an ultra-diluted complex on polymorphonuclear leukocyte function and respiratory scores of weaned Holstein calves immediately after grouping

The aim of the study was to evaluate the effect of an ultra-diluted complex supplementation as a prophylactic strategy on immunity, performance, and respiratory scores of weaned Holstein calves immediately after grouping. Thirty-six weaned Holstein female calves (80.4±1.3 days old; 105.6±10.4 kg) were allocated to 6 pens (n=6 per pen) in a completely randomized design experiment in a double-blind, placebo-controlled trial. During a 28 days period, animals received a total mixed ration and were enrolled into two different groups (n=18 per group): 1) Control (basal diet + calcium carbonate, top-dressed at 30 g/animal/d – ultra-diluted placebo vehicle), or 2) ultra-diluted complex (basal diet + TopVita™-Real H, top-dressed at 30 g/animal/d – Sulphur:10-60 + Viola tricolor:10-14 + Caladium seguinum:10-30 + Zincum oxydatum:10-30 + Phosphorus:10-60 + Cardus marianus:10-60 + Colibacillinum:10-30 + Podophyllum:10-30 + Vehicle: calcium carbonate; q.s. 1kg). Blood samples were collected from each heifer at enrollment and 28 days later to assess polymorphonuclear leukocyte (PMNL) function and blood cell count. Body weight was assessed at enrollment and 28 days later at the end of the study. Regarding respiratory-screening process, a calf scoring system modified for calves in group pens was used. There was no effect of prophylactic ultra-diluted treatment on PMNL, nor it affected lymphocytes count and its ratio. Besides, the ultra-diluted product did not affect body weight and ADG. Further, no effect was observed in respiratory scores throughout the study period. In conclusion, the ultra-diluted complex did not improve blood cells count and PMNL function, nor it had impact on the performance of weaned Holstein calves after grouping.

Concordance of 24- and 48-h diagnostic follow-up ascitic fluid polymorphonuclear leukocyte count in the guidance of the antibiotic therapy in spontaneous bacterial peritonitis

Background Spontaneous bacterial peritonitis (SBP) is an ascitic fluid infection in patients with liver cirrhosis in the absence of surgical causes. The drop of the ascitic fluid polymorphonuclear leukocyte count (AFPC) ≥25% of baseline 48h post-start of antibiotics is a predictor of antibiotic response. This study was designed to compare the diagnostic accuracy of AFPC 24h of antibiotic to the standard 48h. Three hundred ninety-nine SBP patients were classified into 2 groups. Group I (31.1%) are patients that lacked ≥25% drop and group II (68.9%) the opposite. Results The average age was 51.99 ±11.21 years. Most patients were males (70.9%), normotensive (75.8%), non-diabetics (50.8%), and without recent intake history of proton pump inhibitors (75.8%) and B-blockers (77%). Group II patients had statistically significant (p <0.05) serum sodium 129 (7) vs. 128 (8) and history of diabetes mellitus 60.3% vs. 39.7%. The baseline AFPC did not differ statistically between groups I and II (p>0.05). Group II patients compared to group I had statistically (p =0.001) lower AFPC 24h [800 (970) vs. 1100 (1700) cell/mm3], higher percent drop of the AFPC 24h [28.09 (24) vs. −10.17 (35)], and ≥25% drop [154 (90.6%) vs. 16 (9.4%)]. The 24h AFPC >980 cell/mm3 was associated with AFPC 48h non-response (AUROC =0.634, p =0.001, 58.87% sensitivity, 64.36% specificity). The 24-h AFPC percent drop >8% was associated with AFPC 48h response (AUROC =0.849, p=0.001, 85.82% sensitivity, 80.49% specificity). Conclusion Concordance of 24- and 48-h diagnostic follow-up ascitic fluid polymorphonuclear leukocyte count in the guidance of the antibiotic therapy.