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PubMed1977

Extrachromosomal inheritance in Schizosaccharomyces pombe. III. Isolation and characterization of paromomycin-resistant mutants.

In the antimycin--resistant mutant anar-8 of the fission yeast Schizosaccharomyces pombe (Sch.p.) spontaneous mutants were isolated showing high resistance to the aminoglycoside antibiotic paromomycin. All mutants were resistant to the structurally related antibiotic neomycin. Tetrad analysis, mitotic segregation analysis, and mitotic haploidization revealed extrachromosomal, very likely mitochondrial inheritance. In contrast to the rapid segregation of mitochondrial markers in zygotic clones of Saccharomyces cerevisiae (S.c.) the heteroplasmic state of diploids proved to persist for at least 50 generations after zygote formation. Stationary cultures of the paromomycin-resistant mutants parr-106 and parr-112 contain up to 6% respiratory-deficient mutants, but no reversion to paromomycin-sensitivity was observed among 1700-1800 colonies tested. The ability of mutant anar-8 to produce spontaneously respiratory-deficient mutants could be separated from the antimycin-resistant phenotype of anar-8.

Ascomycota↗
PubMed1989

The paromomycin resistance mutation (parr-454) in the 15 S rRNA gene of the yeast Saccharomyces cerevisiae is involved in ribosomal frameshifting.

The leaky expression of the yeast mitochondrial gene oxi1, containing a framshift mutation (+1), is caused by natural frameshift suppression, as shown previously (Fox and Weiss-Brummer 1980). A drastic decrease in the natural level of frameshifting is found in the presence of the parr-454 mutation, localized at the 3' end of the 15 S rRNA gene. This mutation causes resistance to the antibiotic paromomycin in the yeast strains D273-10B and KL14-4A (Li et al. 1982; Tabak et al. 1982). The results of this study imply that in the yeast strain 777-3A this mutation alone is sufficient for restriction of the level of natural frameshifting but is insufficient to confer resistance to paromomycin. A second mutation, arising spontaneously with a frequency of 10(-4) leads, in combination with the parr-454 mutation, to full paromomycin resistance in strain 777-3A.

Base Sequence↗
PubMed2005

The efficacy of an oral treatment with paromomycin against an experimental infection with Giardia in calves.

A controlled and blinded study was conducted to evaluate the efficacy and safety of a treatment with paromomycin sulphate against an experimental Giardia infection in calves. Animals were infected with 10(5)Giardia cysts of cattle origin and were either treated 11 days later with 25, 50 or 75 mg paromomycin/(kg body weight per day) during 5 consecutive days or not treated (control group). Efficacy was evaluated based on reduction in cyst excretion. Furthermore weight gain and diarrhea scores were monitored. In the group treated with 75 mg/kg per day there was a 100% reduction in cyst excretion until 9 days after the start of the treatment (D9) and a very high reduction (> or =98%) until D13. There was a high reduction (> or =93%) until D9 and D13 in the groups treated with 25 and 50 mg/kg, respectively. The cumulative cyst excretion on D13 was significantly (P<0.05) lower in the groups treated with 75 and 50 mg/kg compared to the control group. Although there was a trend towards higher weight gain and less diarrhea in the treated groups, differences between groups were not significant. No adverse reactions to the paromomycin treatment were recorded. Furthermore, the need for reliable parameters for evaluation of treatments against protozoal infections is emphasised.

Administration, Oral↗
PubMed2000

Field trial on the therapeutic efficacy of paromomycin on natural Cryptosporidium parvum infections in lambs.

The objective of this study was to evaluate the therapeutic efficacy of paromomycin against cryptosporidiosis in naturally infected lambs under field conditions. The 36 cross-bred neonatal lambs, 3-10 days old, were used. On the first day that lambs showed diarrhea (Day 1) they were randomly divided into three groups. The infected control group (14 lambs) remained unmedicated whereas the two other groups were orally medicated with paromomycin solution (Humatin((R)), Parke Davis, France): 12 lambs (Group A) at 100mg/kg per day for three consecutive days (Days 1-3) and 10 lambs (Group B) at 200mg/kg per day for two days (Days 1 and 2). Drug efficacy was assessed by evaluating the presence of diarrhea, oocyst shedding and weight gains from Days 1 to 23. The results show the efficacy of paromomycin in reducing both cryptosporidial oocyst output and severity of clinical signs. On Day 4, all unmedicated lambs remained infected and excreted large numbers of cryptosporidial oocysts (mean score: 2.5) whereas oocyst output had stopped in most medicated lambs (>60%) and low numbers of oocysts were excreted in the remaining lambs (mean score: 0.45 in Group A and 1 in Group B). Mean oocyst excretion was significantly reduced in medicated lambs from Days 2 to 5 (P<0.05). Treatment also reduced, but not completely prevented, clinical symptoms although diarrhea stopped in most medicated lambs just after drug withdrawal. The mean weight gains of Group A lambs were higher than that of unmedicated lambs throughout the study and statistically significant differences were found from Days 1 to 11 (1.99+/-0.81 versus 1.47+/-0.53) (P<0.05). By contrast, the growth rate of Group B lambs from Days 11 to 23 was impaired when compared with the two other groups (P<0.05) although no significant differences were found at the end of the study (Days 1-23).

Animals↗
PubMed1997

Determination of paromomycin in human plasma and urine by reversed-phase high-performance liquid chromatography using 2,4-dinitrofluorobenzene derivatization.

A sensitive high-performance liquid chromatographic method for the determination of paromomycin in human plasma and urine was developed. Paromomycin was quantitated following pre-column derivatization with 2,4-dinitrofluorobenzene (DNFB). The chromatographic separation was carried out on a C18 column at 50 degrees C using a mobile phase consisting of 64% methanol in water adjusted to pH 3.0 with phosphoric acid. The eluents were monitored by UV detection at 350 nm. The linearity of response for paromomycin was demonstrated at concentrations from 0.5 to 50 microg/ml in plasma and 1 to 50 microg/ml in urine. The relative standard deviation of the assay procedure is less than 5%.

Anti-Bacterial Agents↗
PubMed2001

Crystal structure of paromomycin docked into the eubacterial ribosomal decoding A site.

BACKGROUND: Aminoglycoside antibiotics interfere with translation in both gram-positive and gram-negative bacteria by binding to the tRNA decoding A site of the 16S ribosomal RNA. RESULTS: Crystals of complexes between oligoribonucleotides incorporating the sequence of the ribosomal A site of Escherichia coli and the aminoglycoside paromomycin have been solved at 2.5 A resolution. Each RNA fragment contains two A sites inserted between Watson-Crick pairs. The paromomycin molecules interact in an enlarged deep groove created by two bulging and one unpaired adenines. In both sites, hydroxyl and ammonium side chains of the antibiotic form 13 direct hydrogen bonds to bases and backbone atoms of the A site. In the best-defined site, 8 water molecules mediate 12 other hydrogen bonds between the RNA and the antibiotics. Ring I of paromomycin stacks over base G1491 and forms pseudo-Watson-Crick contacts with A1408. Both the hydroxyl group and one ammonium group of ring II form direct and water-mediated hydrogen bonds to the U1495oU1406 pair. The bulging conformation of the two adenines A1492 and A1493 is stabilized by hydrogen bonds between phosphate oxygens and atoms of rings I and II. The hydrophilic sites of the bulging A1492 and A1493 contact the shallow groove of G=C pairs in a symmetrical complex. CONCLUSIONS: Water molecules participate in the binding specificity by exploiting the antibiotic hydration shell and the typical RNA water hydration patterns. The observed contacts rationalize the protection, mutation, and resistance data. The crystal packing mimics the intermolecular contacts induced by aminoglycoside binding in the ribosome.

Amino Acid Motifs↗
PubMed2003

Comparison of X-ray crystal structure of the 30S subunit-antibiotic complex with NMR structure of decoding site oligonucleotide-paromomycin complex.

Aminoglycoside antibiotics that bind to 16S ribosomal RNA in the aminoacyl-tRNA site (A site) cause misreading of the genetic code and inhibit translocation. Structures of an A site RNA oligonucleotide free in solution and bound to the aminoglycosides paromomycin or gentamicin C1a have been determined by NMR. Recently, the X-ray crystal structure of the entire 30S subunit has been determined, free and bound to paromomycin. Distinct differences were observed in the crystal structure, particularly at A1493. Here, the NMR structure of the oligonucleotide-paromomycin complex was determined with higher precision and is compared with the X-ray crystal structure of the 30S subunit complex. The comparison shows the validity of both structures in identifying critical interactions that affect ribosome function.

Anti-Bacterial Agents↗
PubMed1985

Anthelmintic effects of bithionol, paromomycin sulphate, flubendazole and mebendazole on mature and immature Hymenolepis nana in mice.

The anthelmintic effects of anti-tapeworm drugs, bithionol, paromomycin sulphate, flubendazole and mebendazole on immature and mature Hymenolepis nana in mice were compared. Immature worms were not affected by paromomycin sulphate or flubendazole administered for 12 consecutive days (days one to 12 after infection) at 100 mg/kg/day but 48% and 100% of H. nana were eliminated from mice by bithionol and mebendazole respectively, at the same dosage regimen. Bithionol, paromomycin sulphate, flubendazole and mebendazole given at 100 mg/kg/day for five consecutive days (days 12 to 16 after infection) eliminated 32%, 29%, 36% and 100% of mature worms respectively. 10 and 20 mg of mebendazole/kg/day for five consecutive days (days 12 to 16 after infection) had little effect on mature worms whereas 50 and 100 mg/kg/day for the same period eliminated 99% and 100% of mature worms, respectively. ED50 of mebendazole in the elimination of mature H. nana was 14 or 15 mg/kg/day for five days from the reduction in dry weight or in number of worms recovered respectively. The effects of mebendazole given 2 to 4 days, 8 to 10 days or 13 to 15 days after infection at 100 mg/kg/day were compared. Very low, if any, activity of the drug given 2 to 4 days after infection was seen, whereas the drug given 8 to 10 days or 13 to 15 days after infection eliminated 84% and 86% of H. nana respectively.

Animals↗
PubMed1984

Effect of ethanol, phenol, formamide, dimethyl sulfoxide, paromomycin, and deuterium oxide on the fidelity of translation in a brain cell-free system.

The effects of six different agents (ethanol, phenol, formamide, dimethyl sulfoxide, heavy water, and a misreading-inducing antibiotic, paromomycin) on the activity and the accuracy of poly(U) translation have been compared under a range (2.5-12 mM) of Mg2+ concentrations in a rat brain cell-free system. The effect of most of these agents was remarkably sensitive to the Mg2+ concentration under which the assay was made. Ethanol decreased the fidelity of translation, and the efficiency of ethanol was increased 3-10-fold by higher Mg2+ concentrations. The effect of paromomycin was identical with that of ethanol, despite its very different structure. Formamide, a "RNA denaturant", increased the accuracy of translation under all Mg2+ concentrations tested. Dimethyl sulfoxide, another type of RNA denaturant, decreased the accuracy of translation under all Mg2+ concentrations tested. Phenol increased the accuracy of translation at high Mg2+ concentrations but decreased it at low Mg2+ concentrations. D2O did not change to any appreciable extent the accuracy of translation, at all the Mg2+ concentrations used. There exists a cooperativity between the effects of Mg2+ and ethanol, Mg2+ and paromomycin, and Mg2+ and dimethyl sulfoxide on the fidelity of translation; no such cooperativity was detected between Mg2+ and formamide and between Mg2+ and D2O. The differential effects of dimethyl sulfoxide and formamide are interpreted in terms of their different dielectric constants. The dielectric constant of dimethyl sulfoxide is higher than that of water, while that of formamide is low er.

Animals↗
PubMed1998

MTO1 codes for a mitochondrial protein required for respiration in paromomycin-resistant mutants of Saccharomyces cerevisiae.

Mutations in MTO1 express a respiratory defect only in the context of a mitochondrial genome with a paromomycin-resistance allele. This phenotype is similar to that described previously for mss1 mutants by Decoster, E., Vassal, A., and Faye, G. (1993) J. Mol. Biol. 232, 79-88. We present evidence that Mto1p and Mss1p are mitochondrial proteins and that they form a heterodimer complex. In a paromomycin-resistant background, mss1 and mto1 mutants are inefficient in processing the mitochondrial COX1 transcript for subunit 1 of cytochrome oxidase. The mutants also fail to synthesize subunit 1 and show a pleiotropic absence of cytochromes a, a3, and b. In vivo pulse labeling of an mto1 mutant, however, indicate increased rates of synthesis of other mitochondrial translation products. The respiratory defective phenotype of mto1 and mss1 mutants is not seen in a paromomycin-sensitive genetic background. The visible absorption spectra of such strains indicate a higher ratio of cytochromes b/a and elevated NADH- and succinate-cytochrome c reductase activities. To explain these phenotypic characteristics, we proposed that the Mto1p.Mss1p complex plays a role in optimizing mitochondrial protein synthesis in yeast, possibly by a proofreading mechanism.

Anti-Bacterial Agents↗
PubMed1989

Studies on the topical treatment of experimental cutaneous leishmaniasis: the therapeutic effect of methyl benzethonium chloride and the aminoglycosides, gentamicin and paromomycin.

BALB/c mice infected with either Leishmania major or Leishmania mexicana were treated twice a day for 10 days with an ointment containing 15% gentamicin or paromomycin, with or without 12% methylbenzethonium chloride (MBCl). It was found that topical application of either paromomycin or MBCl cured the parasite lesion, and that combined treatment with the two compounds had an additive effect. However, after four days' therapy there was a severe inflammatory response at the treatment site, and in most experiments mice relapsed and renewed lesion growth was observed. It is suggested that a non-specific inflammatory reaction may be an important component of the therapeutic response. In further experiments, L. major infected mice treated with paromomycin and MBCl which had cured but not relapsed 58 days after treatment were challenged with a similar dose of the homologous parasite. Lesions developed 16 days post-infection, and the number of parasites recovered from these lesions was similar to that recovered from lesions in control mice. Therefore no protective immunity had been induced by chemotherapy.

Administration, Topical↗
PubMed1998

In-vitro activities of paromomycin and lasalocid evaluated in combination against Cryptosporidium parvum.

Using a chemiluminescence immunoassay, paromomycin and lasalocid were shown to inhibit Cryptosporidium parvum growth in Madin-Darby canine kidney cells in a concentration-dependent manner. The median effective concentrations (EC50s) for paromomycin and lasalocid were 1184 mg/L and 0.4 mg/L, respectively. Neither drug was cytotoxic to host cells at concentrations up to five times their EC50s. Drug combination studies were conducted and the resulting data were analysed by the median-effect principle and combination index method. Statistically significant synergy was observed when combinations of paromomycin and lasalocid were used at ratios of 5000:1 and 2500:1. A possible mechanism for synergy is discussed.

Animals↗
PubMed2006

Comparison between the efficacy of photodynamic therapy and topical paromomycin in the treatment of Old World cutaneous leishmaniasis: a placebo-controlled, randomized clinical trial.

BACKGROUND: The optimal treatment for cutaneous leishmaniasis (CL) is not known. Topical paromomycin is one of the many drugs that have been suggested for the treatment of CL caused by Leishmania major. Recently, topical photodynamic therapy (PDT) has been reported to be effective in the treatment of CL. AIMS: To compare the parasitological and clinical efficacy of PDT vs. topical paromomycin in patients with Old World CL caused by L. major in Iran. METHODS: In this trial, 60 patients with the clinical and parasitological diagnosis of CL were recruited and were randomly divided into three treatment groups of 20 subjects each. Group 1 was treated with weekly topical PDT, and groups 2 and 3 received twice-daily topical paromomycin and placebo, respectively. The duration of treatment was 4 weeks for all groups. These groups were followed for 2 months after the end of treatment. RESULTS: In total, 57 patients with 95 lesions completed the study. At the end of the study, complete improvement was seen in 29 of 31 (93.5%), 14 of 34 (41.2%) and 4 of 30 lesions (13.3%) in groups 1, 2 and 3, respectively (P<0.001). At the same time point, 100%, 64.7% and 20% of the lesions had parasitological cure in group 1, 2 and 3, respectively (P<0.001). CONCLUSION: Topical PDT can be used safely as a rapid and highly effective alternative treatment choice for Old World CL in selected patients.

Administration, Topical↗
PubMed1995

Chemoprophylaxis of Cryptosporidium parvum infection with paromomycin in kids and immunological study.

The anticryptosporidial activity of paromomycin, a natural antibiotic weakly absorbed when administered per os, was assessed in goat kids experimentally infected once via the oral route with 10(6) Cryptosporidium parvum oocysts. Paromomycin used prophylactically at a dose of 100 mg/kg of body weight per day from day-1 to day 10 (day 0 was the inoculation day) prevented infection during the period of drug administration. A delayed low infection was suggested by an antibody rise, but the infection developed below the microscopic detection limits. This low parasite development induced a partial immunity in kids, which reacted immunologically to a challenge on day 21 without symptoms or detectable oocyst shedding. So, paromomycin is a good candidate for field trials because it is prophylactically effective against experimental C. parvum infection and well tolerated by animals. This drug would be useful in an adapted form as an anticryptosporidial agent for neonatal ruminants.

Animals↗
PubMed1998

Comparative efficacy evaluation of dicationic carbazole compounds, nitazoxanide, and paromomycin against Cryptosporidium parvum infections in a neonatal mouse model.

The efficacies of dicationic carbazole compounds, nitazoxanide (NTZ), and paromomycin were evaluated against the AUCp1 isolate of Cryptosporidium parvum by using a neonatal mouse model. Compounds were solubilized or suspended in deionized water and administered orally by gavage to neonatal mice at a constant dose rate on days 0 to 5 (treatment started on day 0). Dose rates varied for individual carbazole compounds but ranged from 0.65 to 20 mg/kg of body weight. NTZ was tested at 100 and 150 mg/kg, and paromomycin was tested at 50 mg/kg. Efficacies were determined by comparing numbers of oocysts present in treated versus control mice at necropsy examination on day 6. Demonstrable efficacy was observed for several carbazole compounds, based on significant reductions in the numbers of oocysts recovered from treated mice versus control mice. Compounds 1, 7, and 10 (19.0 mg/kg) reduced oocyst passage in treated mice to less than 5% of that in control mice. Treatment with compounds 6, 8, and 9 (17.0 mg/kg) resulted in reductions of oocyst output to less than 10% of that in controls. Although they were not comparable in efficacy to compounds 1, 6, 7, 8, 9, and 10, treatment with other carbazole compounds resulted in statistically significant reductions in oocyst output in treated versus control mice. Compound 1 retained efficacy resulted in reduction of oocyst output to approximately 6% of that in controls when the dose was reduced to 5 mg/kg. Further reductions in the dose rate resulted in considerable reductions in anticryposporidial activity. Likewise, the efficacies of compounds 9 and 10 were reduced substantially when the doses were lowered to one-half the screening dose. Paromomycin yielded excellent activity (reduction of oocyst output to <2% of that in controls) at a dose of 50 mg/kg. NTZ yielded moderate efficacy as powder and injectable formulations administered at 100 mg/kg orally (reduction of oocyst output to 42 and 26% of that in controls, respectively). Oral administration of the injectable formulation of NTZ at a dose of 150 mg/kg resulted in improved efficacy (oocyst output, <5% of that in controls).

Animals↗
PubMed2000

Early bactericidal activity of paromomycin (aminosidine) in patients with smear-positive pulmonary tuberculosis.

The early bactericidal activity of the aminoglycoside paromomycin (aminosidine) in doses of 7.5 and 15 mg/kg of body weight was measured in 22 patients with previously untreated smear-positive pulmonary tuberculosis. The fall in log(10) CFU per milliliter of sputum per day during the first 2 days of treatment for 7 patients receiving a paromomycin dosage of 7.5 mg/kg/day was 0.066, with a standard deviation (SD) of 0.216 and confidence limits from -0.134 to 0.266, and that for 15 patients receiving 15 mg/kg/day was 0.0924, with an SD of 0.140 and confidence limits from 0.015 to 0.170. The difference between the mean and zero was not significant for the 7. 5-mg/kg dose group but was significant for the 15-mg/kg dose group (t = 2.55, P = 0.023). Since paromomycin has no cross-resistance with streptomycin and has no greater toxicity than other aminoglycosides, these results suggest that it has the potential to substitute for streptomycin in antituberculosis regimens and may be a particularly valuable addition to the drug armamentarium for the management of multidrug-resistant tuberculosis.

Adolescent↗
PubMed1997

Pilot studies of azithromycin, letrazuril and paromomycin in the treatment of cryptosporidiosis.

Pilot studies of the safety and efficacy of 3 drugs thought to have anticryptosporidial activity were carried out to determine whether any of them are suitable for large-scale clinical trials. Open studies of the use of azithromycin, letrazuril and paromomycin in patients with acquired immunodeficiency syndrome (AIDS) and confirmed cryptosporidial diarrhoea for at least a month. Azithromycin 500 mg daily was ineffective. Letrazuril 150-200 mg daily was associated with an improvement in symptoms in 40% of patients treated and cessation of excretion of cryptosporidial oocysts in the stool in 70%; however biopsies remained positive. Paromomycin therapy was associated with a complete resolution of diarrhoea in 60% of patients treated and some improvement in symptoms in a further 5% but it did not eliminate the infection. None of the drugs had any major toxicities. Dose escalation studies of azithromycin should be performed. Letrazuril should be further investigated for efficacy in double-blind placebo-controlled trials. Paromomycin appears to result in prolonged symptomatic remission of cryptosporidial diarrhoea, but has no effect on cryptosporidial cholangitis.

AIDS-Related Opportunistic Infections↗
PubMed1999

Acute renal failure in four cats treated with paromomycin.

Acute renal failure was diagnosed in 4 cats receiving paromomycin orally for treatment of infectious enteritis. All 4 cats responded to fluid therapy and recovered normal or near-normal renal function; however, 3 of the cats subsequently became deaf and developed cataracts. Toxicoses were attributed to a combination of an excessive dosage of paromomycin and absorption of the drug across injured intestinal mucosal epithelium. Pharmacokinetic studies are needed to further define the disposition of paromomycin after oral administration to cats.

Acute Kidney Injury↗