In vitro activity of the lipopeptide derivative (Pal-Lys-Lys-NH), alone and in combination with antifungal agents, against clinical isolates of dermatophytes.

BACKGROUND: An increasing number of antimycotics have become available for the treatment of dermatophytoses; however, there are reports suggesting recalcitrance to therapy or resistance of a dermatophyte against conventional treatment. Lipopeptides represent novel therapeutic drugs with a new mode of action. OBJECTIVES: The aim of this study was to investigate the in vitro effects of the lipopeptide Pal-Lys-Lys-NH(2) (PAL) alone and in combination with standard antifungal agents, such as fluconazole (FLU), itraconazole (ITRA) and terbinafine (TER) against 24 clinical isolates of dermatophytes belonging to four species. METHODS: A broth microdilution method following the Clinical and Laboratory Standards Institute recommendations (M38-A) was used for testing drugs alone and in combination. RESULTS: PAL minimum inhibitory concentrations (MICs) ranged from < or = 0.25 to > 16 microg mL(-1) and they were similar to those of FLU and higher than those of either ITRA or TER. Synergy, defined as a fractional inhibitory concentration (FIC) index of < or = 0.50, was observed in 67%, 52% and 15% of PAL/ITRA, PAL/TER and PAL/FLU interactions, respectively. None of these combinations yielded antagonistic interactions (FIC index > 4). When synergy was not achieved, there was still a decrease in the MIC of one or both drugs used in the combination. CONCLUSIONS: Our study demonstrates that PAL has potential activity against dermatophytes. In addition, the in vitro activity of PAL can be enhanced upon combination with standard drugs. This lipopeptide applied in the form of lacquer, spray or ointment, could represent an interesting new therapy, particularly when combined with conventional treatment in recalcitrant or resistant dermatophyte infections.

Activity of buforin II alone and in combination with azithromycin and minocycline against Cryptosporidium parvum in cell culture.

The in vitro anti-cryptosporidial activity of buforin II alone and in combination with azithromycin and minocycline was investigated. Buforin II showed moderate activity, which increased with increasing concentration to 55.7% suppression of growth at 20 microM. Moreover, its activity was enhanced when it was combined with either azithromycin or minocycline with >90% parasite reduction at the highest concentration tested. Buforin II may be active in inhibiting Cryptosporidium parvum growth in vitro upon combination with either azithromycin or minocycline.

Short-term exposure to membrane-active antibiotics inhibits Cryptosporidium parvum infection in cell culture.

A cell culture system and double fluorogenic staining were used to study the susceptibility of Cryptosporidium parvum to membrane-active antibiotics. Buforin II and magainin II exerted a cytotoxic effect on sporozoites but did not consistently affect oocyst viability. Lasalocid and nigericin demonstrated less activity against sporozoites but reduced the infectivity of oocysts.

Inhibition of growth of Pneumocystis carinii by lactoferrins alone and in combination with pyrimethamine, clarithromycin and minocycline.

The in vitro activity of lactoferrins alone and in combination with clarithromycin, minocycline and pyrimethamine was investigated against three clinical isolates of Pneumocystis carinii. Susceptibility was tested by inoculating isolates on to cell monolayers and determining the parasite count after 72 h incubation at 37 degrees C. The culture medium was supplemented with serial dilutions of each agent. At 20 mg/L, bovine lactoferrin, the most active agent, suppressed the growth of cystic and trophic forms by >60%. Human lactoferrin, at the same concentration, suppressed the growth of cystic and trophic forms by >50%. Lactoferrins at 20 mg/L combined with clarithromycin 4 mg/L had high anti-P. carinii activity, with a >90% decrease in cystic and trophic form counts. Our study suggests that lactoferrins may inhibit P. carinii growth in vitro and act synergically with other clinically used compounds. These findings lend experimental support to the use of iron-chelating agents in the therapy of pneumocystis infections.

Treatment of murine cryptococcal meningitis with UR-9751 and UR-9746.

In these studies, we compare the efficacy of two new azole antifungals with fluconazole in a murine model of cryptococcal meningitis. Mice were infected intracranially. Beginning one day later, groups of 7-10 mice were treated through to day 10 orally with UR-9751 or UR-9746 at 0.1, 0.25, 0.5, 1 or 10 mg kg(-1) day(-1) or fluconazole at 10 mg kg(-1) day(-1). At 10 mg kg(-1) day(-1), all three drugs prolonged survival over controls, but at 1 mg kg(-1) day(-1) only UR-9746 prolonged survival. Tissue counts were more varied on mice sacrificed 8 days after infection. In general, both UR drugs were equal or more potent than fluconazole, and UR-9751 was more effective than UR-9746.

In vitro anticryptosporidial activity of ranalexin alone and in combination with other peptides and with hydrophobic antibiotics.

The in vitro activity of ranalexin alone and in combination with other cationic peptides, macrolides, rifampin, and rifabutin was investigated against a clinical isolate of Cryptosporidium parvum. Susceptibility tests were performed by inoculation of the isolate onto cell monolayers and determining the parasite count after 48 h of incubation at 37 degrees C. Antibiotic-free cultures were used as controls in the study. Ranalexin showed low anticryptosporidial activity: it suppressed the growth of parasites by > or = 40% at 50 microM. Ranalexin showed enhanced activity when it was combined with noninhibitory concentrations of other compounds: a 74.4-94.1% reduction in the number of parasites was observed when ranalexin 50 microM was combined with magainin II 50 microM, indolicidin 50 microM, clarithromycin 8 mg/l, azithromycin 8 mg/l, rifampin 8 mg/l, and rifabutin 8 mg/l. The results suggest that ranalexin may be effective in inhibiting Cryptosporidium parvum growth in vitro upon combination with other peptides and hydrophobic antibiotics.

In-vitro activity of polycationic peptides against Cryptosporidium parvum, Pneumocystis carinii and yeast clinical isolates.

The in-vitro activity of magainin II, indolicidin and ranalexin against 14 clinical isolates of eukaryotic microorganisms was evaluated. Antifungal susceptibility testing was performed by broth microdilution, and activity against Pneumocystis carinii and Cryptosporidium parvum was determined by inoculation on to cell monolayers. For yeasts, peptide MICs and MFCs ranged from 6.25 to > 50 mg/L. Ranalexin showed the highest activity against Candida spp., while magainin II demonstrated greatest anticryptococcal activity. The peptides suppressed the growth of P. carinii by > or = 50% and > or = 90% at 5 and 50 microM, respectively, with the exception of indolicidin. Ranalexin, the most effective compound against C. parvum, suppressed its growth by > or = 40% at 50 microM.

Infection due to Absidia corymbifera in a patient with a massive crush trauma of the foot.

We report the case of a patient with a massive crushing trauma of the right foot who developed a local infection due to Absidia corymbifera. Systemic and local antifungal therapy with ketoconazole associated with hyperbaric oxygen therapy (HBO) yielded a rapid clinical and microbiological resolution. Controlled clinical studies are warranted to further elucidate the potential utility of HBO/antifungal combination therapy.

In-vitro activity of lytic peptides alone and in combination with macrolides and inhibitors of dihydrofolate reductase against Pneumocystis carinii.

The in-vitro activity of cecropin P1, magainin II, indolicidin and ranalexin alone and in combination with macrolides and dihydrofolate reductase inhibitors (DHFRs) was investigated against six clinical isolates of Pneumocystis carinii. The susceptibility tests were performed by inoculation of the isolates on to cell monolayers and determining the parasite count after 72 h incubation at 37 degrees C. The culture medium was supplemented with serial dilutions of each agent. The four peptides suppressed the growth of cysts and trophozoites by > or = 50% at 20 microM and 2 microM, respectively, with the exception of indolicidin (cysts: IC50, 20 microM; trophozoites: IC50, 20 microM). The IC90 values of all peptides for either cysts or trophozoites were observed at a concentration of 20 microM. Our data showed that the activity of lytic peptides remained virtually unchanged when they were tested either alone or in combination with macrolides and DHFRs, with the exception of ranalexin: a cysts/trophozoites reduction in the range 77.3-85.1% was observed when ranalexin 2 microM was combined with 4 mg/L of macrolides. Our study suggests that lytic peptides may be effective in inhibiting the growth of P. carinii in vitro. In addition some of these compounds seem to have an effective interaction with hydrophobic antibiotics.

Treatment of histoplasmosis with MK-991 (L-743,872).

BALB/c nu/+ immunocompetent and athymic (nu/nu) mice were infected intravenously with yeast cells of Histoplasma capsulatum. Mice were either given water (controls) intraperitoneally (i.p.) or given MK-991 i.p. once daily or twice daily. Protection was measured as prolonged survival or reduction in tissue counts. MK-991 was protective in immunocompetent mice, prolonging survival and reducing counts in spleen and livers at a dose as low as 0.05 mg/kg of body weight/day. MK-991 was modestly effective in athymic mice at a higher dose, 5 mg/kg/day. These studies suggest that MK-991 may be appropriate for clinical development in histoplasmosis.

Chronic pain: its treatment in geriatric and younger patients.

The response of geriatric patients to a multidisciplinary chronic pain rehabilitation program was measured by comparing outcome data on 17 older patients (55 to 78 years) to data on 20 younger patients (29 to 48 years) treated in the same program. Pretreatment data were obtained at an initial evaluation, and posttreatment data were obtained at the most recent follow-up contact, usually at 12 months after treatment. Treatment outcome was assessed on the basis of eight quantitative measures: pain ratings; health care utilization; activity tolerance; daily "up time"; hours per week spent in paid employment, housework, volunteer work, or school; medication intake; SCL-90R somatization, depression, and anxiety scores; and an overall summary measure. Pretreatment data indicated that older and younger groups were similar on both demographic variables and clinical status. There was a larger percentage of women in the older group. The older patients were initially somewhat more impaired than the younger ones, with nearly four times the rate of health care utilization and almost two times higher medication intake. Both groups improved significantly from pretreatment to posttreatment on most of the eight measures. Older patients showed a greater decrease in health care utilization. Women and men did not respond differentially to treatment. The data indicated that geriatric patients can benefit from chronic pain rehabilitation programs at least as much as, if not more than, younger patients.