[Fundamental and clinical studies on fosfomycin sodium in the field of obstetrics and gynecology]

Fosfomycin sodium (FOM-Na) was studied both fundamentally and clinically in the field of obstetrics and gynecology with following results. It showed good transference into the uterine tissues when given intravenously. The peak concentrations achieved in the uterine tissues following intravenous administration of 2 g of FOM-Na were 26.56 to 53.48 micrograms/g when given as one shot injection and 20.16 to 39.47 micrograms/g as drip infusion. In the serum of vein and uterine artery, peak concentrations of 163.6 to 143.40 micrograms/ml and 120 to 113.12 micrograms/ml were reached following one shot injection and drip infusion, respectively. In general, FOM-Na concentrations in the uterine tissues showed similar changes as those observed for serum concentrations. Clinically, FOM-Na was used in the treatment of 17 cases of obstetrical and gynecological infections at 2 g per dose twice daily as intravenous drip infusions. In all of these cases, good clinical efficacy was obtained. No side effects were observed.

[Value of the aminoglycoside-fosfomycin combination. Apropos of a case of bacterial endocarditis]

The authors report a case of Staphylococcus epidermidis prosthetic valve endocarditis. After two unsuccessful treatments, the association Gentamicin-Fosfomycin provided adequate serum bactericidal titers and had a good efficacy.

A multicenter, randomized parallel double-blind study comparing three antibiotics, cephemic-cofosfolactamine, fosfomycin and cephalexin, in the treatment of systemic infections

In the present multicenter, randomized and double-blind study, performed on 127 hospitalized patients, we compared the effects of three antibiotics (cephemic cofosfolactamine, cephalexin and fosfomycin) in the treatment of acute or recurrent systemic infections. Results show that the percentage of recoveries of clinical symptoms and of bacterial eradications were significantly higher, and associated with a lower rate of side effects in the patients treated by cephemic cofosfolactamine than in those treated by cephalexin or fosfomycin.

Experimental and preliminary clinical experience with absorbable calcium phosphate granules containing an antibiotic or antiseptic for the local treatment of osteomyelitis

Experimental studies on dogs with staphylococcal osteomyelitis showed that it is possible to reduce florid bone suppuration by the use of hydroxyapatite granules containing an antibiotic or antiseptic. In our series the use of flucloxacillin hydroxyapatite granules was superior to other treatment methods. Twelve patients were treated with thorough sequestrectomy, reliable wound closure and suitable stabilization supplemented with an implant of antibiotic or antiseptic hydroxyapatite granules, and an autologous spongiosa graft for large bone cavities or for discontinuity between the bone ends. The results of this preliminary study showed the treatment to be effective.

Protective effect of fosfomycin against aminoglycoside ototoxicity

The protective effect of fosfomycin against aminoglycoside (dibekacin)-induced ototoxicity was studied in rats. Rats were injected with 100 or 50 mg/kg of dibekacin with or without 500 mg/kg of fosfomycin for 60 or 120 consecutive days. Inner ear damage appeared to be more reduced histopathologically in animals given both dibekacin and fosfomycin than in animals given dibekacin alone. Similarly, renal damage appeared to be reduced histopathologically and functionally by the combined administration of dibekacin and fosfomycin. The mechanism of reduced ototoxicity may be as follows: fosfomycin inhibits the accumulation of dibekacin in the kidney, and reduces its concentration in the kidney and serum. Consequently, the amounts of dibekacin reaching the inner ear are decreased, and ototoxicity is reduced.

Chronic granulomatous disease: uptake and intracellular activity of fosfomycin in granulocytes

In chronic granulomatous disease (CGD) polymorphonuclear leukocytes (PMN) are unable to kill phagocytized catalase-positive bacteria. Therefore, patients with CGD are prone to infections and dependent on antimicrobial agents able to penetrate PMN membranes and to act intracellularly. Owing to their good lipid solubility, trimethoprim/sulfamethoxazole and rifampicin passively diffuse the membrane. In contrast, fosfomycin is transported actively into the cell. In normal PMN, it reaches cellular-to-extracellular ratios of 1.83 after 15 min, in CGD-PMN 2.18 after 30 min. At concentrations between 16 and 200 mg/liter, fosfomycin was able to kill staphylococci surviving within CGD-PMN, thus compensating for the bactericidal deficiency in CGD. A combination of low concentrations of fosfomycin (8 mg/liter) plus rifampicin (0.06 mg/liter) was more effective at the intracellular level than either agent alone. Apart from a stimulation of PMN-chemiluminescence of yet unknown significance, the agent did not interfere with other neutrophil functions. Clinical investigations are indicated to study whether fosfomycin can be added to the small number of antibiotics useful in CGD.

[Preventive effect of fosfomycin on the renal toxicity of cisplatin]

Cisplatin caused toxic effects in adult male rats, such as renal disturbance, decrease of platelet and WBC, increase of RBC, elevation of GPT and GOT activity, decrease of plasma protein and albumin, loss of body weight gain and lethal effect when treated intravenously with 1 mg/kg/day of cisplatin for 12 days. Fosfomycin (FOM) exerted preventive effects on the renal disturbance, the changes in blood cells and plasma protein and the lethal effect induced by cisplatin when treated with a combination of FOM and cisplatin. However, FOM did not prevent the cisplatin-induced effects on GPT and GOT activity and body weight gain. These results suggest that FOM prevents the cisplatin-induced disturbance of renal and hematopoietic function but does not the cisplatin-induced hepatic disturbance.

Bactericidal activity of cefotaxime and fosfomycin in cerebrospinal fluid during the treatment of rabbit meningitis experimentally induced by methicillin-resistant Staphylococcus aureus

The purpose of this study was to evaluate the therapeutic effect of cefotaxime (CTX) and fosfomycin (FOS), alone or in combination, in an experimental meningitis, with cerebrospinal fluid (CSF) concentrations of the two antibiotics reproducing those obtained in human CSF during bacterial meningitis. With a dose of 50 mg/kg of CTX and 100 mg/kg of FOS injected i.v. (CTX over 0.5 h and FOS over 3 h), CSF concentrations were comparable to those observed in man. In a series of five rabbits per treatment group, the bacterial population was counted before and after treatment (two doses with a six-hour interval) with CTX, FOS or CTX + FOS (CTX over 0.5 h before the end of FOS infusion). By the 12th hour of treatment, the percentage of bacteria surviving in CSF compared to the initial population was 4.35% for CTX, 0.20% for FOS and 0.19% for CTX + FOS. Thus, it seemed that CTX + FOS was not more active than FOS alone. In another series of four rabbits per group, the bactericidal effect was followed at T0, T6, T12, T24 and T48 after treatment (two doses with a six-hour with a six-hour interval). With CTX, a variable drop in bacterial count from one rabbit to the other occurred during the first 12 h, and then a bacteriostasis followed. With FOS, a quick bactericidal effect was observed during the first 12 h, becoming slower during the following 36 h (0.03% of bacteria surviving at the 48th hour). With CTX and FOS in combination, a quick bactericidal effect was achieved, remaining steady over a 48-hour period (0.001% of bacteria surviving at the 48th hour).

Reduction of cisplatin ototoxicity by fosfomycin in animal model

The protective effect of fosfomycin against cisplatin-induced ototoxicity was studied in rats. Sixty-four Fischer rats were injected intravenously with daily doses of 1, 2, 5, and 10 mg/kg of cisplatin with or without 300 mg/kg of fosfomycin for a varying period from 1 to 10 days. The total dose of 10 mg/kg of cisplatin was given equally in all animals. Inner ear damage appeared to be more reduced histopathologically in animals given both cisplatin and fosfomycin than in animals given cisplatin alone. Similarly, renal damage appeared to be reduced histopathologically and functionally by the combined administration of cisplatin and fosfomycin.

[Diffusion of fosfomycin into the cerebrospinal fluid in purulent meningitis]

Cerebrospinal fluid levels of fosfomycin were measured in 10 patients with bacterial meningitis. Fosfomycin 200 mg/kg/day was administered in three 4-hour intravenous infusions. The antibiotic was associated with amoxicillin in 9 patients and with cefotaxime in one. Cerebrospinal fluid was obtained on the 2nd and 5th days of treatment, 2 hours after the end of the infusion. The mean CSF fosfomycin levels were 31 mg/l on the 2nd day and 37.2 mg/l on the 5th day. These levels were higher than the MIC 90 for most bacteria encountered in meningitis. Fosfomycin could be used to treat some cases of bacterial meningitis, but always in association with another antibiotic.

Other antibiotics

This is a survey of the pharmacokinetics and mechanisms of action, orthopedic use, antimicrobial activity, and adverse reactions to erythromycin, lincomycin and clindamycin, tetracycline, chloramphenicol, polymyxins, vancomycin, and fosfomycin. Although these antibiotics are rarely preferred to more active drugs such as the beta-lactams or aminoglycosides in orthopedic sepsis, they are nevertheless highly beneficial and in some situations can be the first-choice drug.

Clinical chemotherapeutic evaluation of fosfomycin plus amoxicillin (co-fosfolactamine): a prospective double-blind clinical trial

Seventy-three hospitalized patients with urinary tract infections (UTI) were included in a double-blind study and received at random either fosfomycin or fosfomycin plus amoxicillin (CFL) in a pre-fixed combination, in order to evaluate the effectiveness of the CFL. CFL was administered orally to 39 patients at the daily dosage of 1 g every 8 h for 6 days (666 mg of fosfomycin and 334 mg of amoxicillin) while fosfomycin was given orally to 34 patients at the daily dosage of 666 mg every 8 h for 6 days. A bacteriological cure was observed in 97.4% of the patients treated with CFL, while in the fosfomycin group the bacterial eradication was obtained only in 82.3% (P less than 0.05). CFL showed a more rapid bactericidal activity than fosfomycin. In addition, CFL was more effective than fosfomycin against "difficult" Gram-negative bacteria such as Proteus spp. and Pseudomonas aeruginosa. Both antibiotics were well tolerated. Our limited experience revealed that CFL induces a negligible degree of resistant strains, and fewer than fosfomycin. Thus we conclude that CFL seems to be a useful antibiotic combination in the treatment of UTI.

[Clinical trial of fosfomycin for Campylobacter enteritis]

Forty-three children and 4 adults with Campylobacter enteritis were studied in the treatment of fosfomycin (FOM). FOM was administered per orally in doses ranging from 50 to 100 mg/kg/day for children and 3 g/day for adults for 5 days. Main symptoms such as diarrhea and fever were disappeared within 2 days on the average. Campylobacter jejuni in stool specimen disappeared within a week in 95% of these patients. The duration of main symptoms and the period of positive stool culture were evidently shortened in FOM-treated group compared with non-treated group. All of the isolated strains were sensitive to FOM by mono-concentration disk method. MIC50 of these strains remained between 1.56 and 3.13 micrograms/ml. None of these MIC was beyond 12.5 micrograms/ml.

[Pharmacokinetics and clinical studies of fosfomycin in bile duct infections]

Serum and bile levels of fosfomycin sodium (FOM-Na) were evaluated and the pharmacokinetic parameters were estimated in 10 patients with various forms of biliary drainage (PTCD or T-tube). Clinical trials of FOM-Na were also performed in another 11 patients with bile duct infections and the clinical efficacy was estimated. Mean serum level of FOM-Na after drip infusion of 2 g fosfomycin sodium was 145.43 micrograms/ml at 1 hour, meanwhile bile level was 31.49 micrograms/ml at 2 hours. Serum level of FOM-Na was interpreted by the pharmacokinetic analysis after the damping GAUSS-NEWTON method using the one-compartment open model and bile level of FOM-Na by the damping GAUSS-NEWTON method and deconvolution method. Mean Vd was 12.16 L/body and half-time of serum level was 1.75 hours. Lag-time of bile level was 0.9 hour, Tmax 2.01 hours. The clinical efficacy of FOM-Na was determined excellent without any adverse effect. FOM-Na was remarkably effective in 91% of the patients. Hence, the first choice of FOM-Na against bile duct infections could be recommended.

[Can fosfomycin reduce the nephrotoxicity of aminoglycosides?]

Fosfomycin is an active antibiotic on Gram positive and Gram negative bacteria with a low toxicity in animals. To treat severe infections, it is recommended to associate fosfomycin with gentamicin. Wistar rats were given one of the following regimens for eight days : 100, 500 or 1 000 mg/kg fosfomycin, 50 mg/kg gentamicin or dibekacin, association of 100, 500, or 1 000 mg/kg fosfomycin and 50 mg/kg gentamicin or dibekacin. Control rats were given a saline solution. No renal histological alterations were identified with fosfomycin 100 mg/kg. Tubular dilatation and brush border rarefaction were observed with fosfomycin 500 and 1 000 mg/kg. These abnormalities did not seem related to fosfomycin itself but rather to the sodium load induced by fosfomycin treatment. A decrease in alanine aminopeptidase activity was noted for all doses of fosfomycin. Renal concentrations of gentamicin and dibekacin were not decreased by concomitant administration of fosfomycin. Fosfomycin, 100 mg/kg, did not change the nephrotoxic potential of gentamicin or dibekacin. Fosfomycin, 500 mg/kg, protected the kidney from the action of gentamicin or dibekacin. This effect seemed to be more pronounced for dibekacin than for gentamicin. Fosfomycin, 1 000 mg/kg, did not induce a more protective effect against the nephrotoxicity of these two aminoglycosides. Thus, we observed that fosfomycin combined with gentamicin or dibekacin reduced the degree of proximal tubular cell alterations, induced less modifications in alanine aminopeptidase, less lysosomal alterations, and a minor modification in sphingomyelinase activity.