Persistence of non-typeable Haemophilus Influenzae in the pharynx of children with adenotonsillar hypertrophy after treatment with azithromycin.

This study was performed in children with adenotonsillar hypertrophy to evaluate the effect of azithromycin (AZT) on the presence of NTHi in monocyte/macrophages (CD14(+) cells) of adenoids/tonsils and the persistence of NTHi after adenotonsillectomy. A total of 36 pediatric patients participated in the study: 20 children were treated with AZT before adenotonsillectomy, and 16 children did not receive the antibiotic prior to surgery. NTHi were identified by culture and PCR in swabs and tissue samples. NTHi was detected in the lysates of CD14(+) cells by fluorescence in situ hybridization (FISH) and by culture. The molecular typing was used to cluster NTHi isolates from each child. The intracellular NTHi was found in 10 (62.5%) untreated patients and was identified in three (15%) azithromycin-treated patients (P = 0.003). The proportion of the persistent NTHi strains was similar in both groups. AZT treatment followed by adenotonsillectomy did not completely eliminate NTHi from pharynges; however, it significantly reduced the risk of carriage of Haemophilus influenzae inside the CD14(+) cells.

Antimicrobial resistance and genotypes of staphylococci from bovine milk and the cowshed environment.

Investigation of antimicrobial resistance and genetic relatedness of staphylococci from milk of cows with mastitis and cowshed environment was the aim of this study. Antimicrobial resistance against 14 antimicrobials were determined by using a disc diffusion method. Genetic similarity between the most frequently isolated species was analysed by PFGE (pulsed-field gel electrophoresis). Haemolytic activity, DNase, protease and esterase production was also investigated. Coagulase-negative Staphylococcus species were isolated from 30.8% of milk samples from cows with mastitis. The most frequently isolated species was Staphylococcus xylosus and yield of these organisms was significantly associated with milk of mastitis cows. S. epidermidis was a predominant penicillin-resistant species. High frequency of resistance to lincomycin was observed among isolates of S. sciuri (54.2%) and S. xylosus (25.9%) from cows with mastitis. PFGE (pulsed-field gel electrophoresis) analysis of 29 Staphylococcus aureus isolates showed the presence of 17 PFGE pulsotypes. Isolates of S. sciuri (n = 36) had unique PFGE patterns. Some S. xylosus isolates from milk and milker's hands had the same PFGE pulsotypes, and this observation could indicate that dairyman may be a potential source of the infection. The pulsotype of each of the remaining isolates of S. xylosus suggested that they might have come from common environmental sources; however, these isolates differed in antibiotic resistance pattern or virulence traits. Therefore, knowledge about antibiotic sensitivity pattern and virulence factors of a CNS isolate, besides its genotype, may be informative in tracking the source of the infection.

Removal of methylene blue from waste water using micellar enhanced ultrafiltration.

Ultrafiltration of micellar solutions containing sodium dodecylsulfate (SDS) and oxyethylated coconut fatty acid methyl esters (OMC-10) and their binary mixtures were studied and used to recover methylene blue. This was achieved through solubilization in mixed negatively charged micelles. Under the experimental conditions used, no significant fouling of the membrane comprising of cellulose, polyethersulfone and polyvinylidene fluoride was observed, with no retardation of ultrafiltration. The introduction of a nonionic surfactant to SDS reduced the critical micelle concentration of mixed micelles and then the concentration of surfactants in the permeate, i.e., from 8.3 x 10(-3)M for SDS to 2.0 x 10(-3) M for the mixture of SDS:OMC-10 = 4:1. Such a tailored surfactant mixture enabled the authors to achieve 93-94% retention of methylene blue using a hydrophilic membrane made of cellulose. Ultrafiltration of micellar solutions could also be considered a research method, helpful in determining important parameters such as micelle loading and the micelle binding constant used to characterize micellar solutions. Additionally the distribution coefficient employed in extraction studies can be resolved.

New cytokine dressings. I. Kinetics of the in vitro rhG-CSF, rhGM-CSF, and rhEGF release from the dressings.

Wound repair-stimulatory activities of various cytokines and growth factors depend on successful delivery of these factors to the injured sites. Here were present the design and preparation of the new collagen- and polyurethane-based dressings containing the recombinant human cytokines-rhG-CSF, rhGM-CSF or rhEGF. To test the efficacy of the retrieval of the incorporated cytokines, their controlled release from the dressings was carried out over three consecutive days using polyurethane sponge as a collector of the extracts. The maximum quantities of the released rhG-CSF, rhGM-CSF and rhEGF reached approximately 25, 50, and 10%, respectively, of the total cytokine contents of the dressings, as assessed by the specific ELISA tests. These data indicate that collagen- and polyurethane dressings containing rhGM-CSF and rhG/CSF may serve as effective tools for the topical delivery of cytokines to wounded tissues.

New cytokine dressings. II. Stimulation of oxidative burst in leucocytes in vitro and reduction of viable bacteria within an infected wound.

Recently, we have developed the new dressings containing rhG-CSF or rhGM-CSF. In the present study we investigated either in vitro or in vivo biological activity of the dressings. Human whole blood samples were incubated with extracts from the collagen- or polyurethane-based dressings containing rhG-CSF or/and rhGM-CSF and phagocytic and oxidative metabolic activities were quantitated using Phagotest or Bursttest kits. The results indicate that both the number of phagocyting cells and the intensity of phagocytosis per cell, as well as the level of the oxidative burst in particular, were stimulated by one or both of the cytokines extracted. Next, the experimental skin wounds in mice were infected with 107 CFU of Pseudomonas aeruginosa strain ATCC 27853 and treated locally with the rhG-CSF-containing dressing. The analysis of the biopsies taken from the wounds indicated that in mice treated with the cytokine-containing dressing on the third day the log of CFU per biopsy was 5.0 vs. 6.2 in the control (P<0.001), and on the 8th day was lower than 4 vs. 5.4 in control (P<0.0001). Our findings clearly suggest that the newly designed dressings containing the incorporated CSFs can be used as effective topical cytokine-delivery system in the treatment of bacterial infections in wounds.

Antibacterial activity of liposome-encapsulated antibiotics against Pseudomonas aeruginosa attached to the matrix of human dermis.

The present studies were undertaken to compare the antibacterial activity of liposome vesicles containing amikacin, ciprofloxacin or polymyxin B in the removal of P. aeruginosa organisms from microcolonies growing on sections of the matrix of human dermis. Encapsulation efficiency of antimicrobials inside cationic liposomes was 30% for amikacin, 50% for ciprofloxacin, and 100% for polymyxin B. The sections of dermis were colonized for 72 h with P. aeruginosa strains isolated from burn wounds. After that time, an intense growth of microorganisms on the dermis surface was observed. The sessile organisms were treated (with mild shaking) with solutions of either liposomal or free amikacin, ciprofloxacin, and polymyxin B for 1 h, and also with a mixture of liposomal or free ciprofloxacin and polymyxin B (1:1) for 20 min. After treatment with liposomal antimicrobials, the mean per cent of viable cells attached to the dermis was 48.7% for liposomal amikacin, 17.4% for liposomal ciprofloxacin, 19.1% for liposomal polymyxin B, and 3.6% for a mixture of liposomal ciprofloxacin and liposomal polymyxin B. Removal of P. aeruginosa from microcolonies growing on the dermal matrix was more effective when liposomal formulations were used compared to the free antibiotics. Therefore, cleansing of the contaminated matrix of human dermis with liposomal ciprofloxacin, liposomal polymyxin B or with the mixture of both liposomal antibiotics seems to increase the efficacy at the removal of attached bacterial cells.

Release of antibiotics from collagen dressing.

Our new collagen dressing has been developed recently. Three types (A, B, and C) of the dressing were prepared in this study. Each type contained bacitracin, neomycin or colistin. The antibiotic was input into: i. collagen sponge (CS)--type A, ii. layer of limited hydrophobicity (LLH)--type B, and iii. into both CS and LLH layers--type C. The final concentration of the antibiotic that resulted from the loading level was 2 mg/cm2 for the dressings of type A and B and 4 mg/cm2 for the dressing of type C. The antibiotics were then extracted from the pieces of dressings for two days through dialysis membrane. Susceptibility of 54 bacterial strains (S. aureus, P. aeruginosa, and Acinetobacter) isolated from burn wounds were tested to the three antibiotics used for preparation of the dressings. The results of the study evidenced that efficiency of released of antibiotics into the extracts depended on the kind of antibiotic and on the type of dressing. The concentration of the antibiotics proved to be much higher than MIC90 values of the bacterial isolates tested in respect to their susceptibility. The dressing containing mixture of the three antibiotics in two layers--CS and LLH is now considered as potentially effective for care of infected wounds. It may be useful for the treatment of infected wounds or for profilaxis of contaminated wounds, ensuring: i. sufficient antimicrobial activity in wound, and ii. optimal wound environment for the presence of collagenic biomaterial on the damaged tissue.

Maturation and survival of spermatozoa in the epididymis of pregnenolone treated hypophysectomized rats.

Adult hypophysectomized male rats were injected daily with 2 mg pregnenolone for 30 days. In these rats the testosterone concentrations in peripheral blood (0.5 ng/ml) and testes (46 ng/g) were appreciably lower than in intact rats (4.1 ng/ml and 167 ng/g, respectively). In hypophysectomized animals treated with pregnenolone the testes and epididymides were much better maintained than the prostates and seminal vesicles. High concentrations of dihydrotestosterone were found to be present in the head (12 ng/g) and body (8 ng/g) of the epididymis of these rats. Although the number of spermatozoa in the distal part of the epididymis of pregnenolone-treated hypophysectomized rats was only 23% of the number found in intact control animals, the spermatozoa were fertile.