Single-dose treatment of bacteriuria in pregnancy

Comparison of the results of single-dose treatment of urinary tract infection in women is confused by differences between published series in the duration of follow-up and in the diagnosis of infection. Pregnancy allows prolonged follow-up in a motivated population, but increases the possibility of false positive diagnosis of infection from midstream urines due to increased vulvovaginal contamination. Suprapubic aspiration (SPA) is safe in pregnancy and accurately confirms the presence or absence of bacteria in the bladder urine. Bacteriuria was diagnosed by SPA in 86 pregnant women. Thirty-seven of these were treated with a single dose of 3 g cephalexin and 49 with 3 days of cephalexin 1 g or of a combined preparation of pivmecillinam-pivampicillin. Both single-dose and 3-day treatments prevented further bacteriuria in 65% of the patients for the remainder of their pregnancies. This is similar to the results achieved with 10-day treatment. If extended trials confirm that single-dose treatment is as effective as conventional treatment with the same drug, then single-dose treatment has the advantages in pregnancy of minimal medication, good patient compliance and lack of side-effects.

The influence of renal functional changes on the intrarenal distribution and urinary kinetics of amdinocillin

The maintenance of effective therapeutic concentrations of antibiotics within the renal parenchyma is an important issue in the management of acute and chronic pyelonephritis. Available clinical data indicate that an important clinical-therapeutic correlation exists between the physiologic state of the kidney and the antibiotic concentrations that can be achieved in the medulla and papilla. Using a healthy canine model, we evaluated the influence of hydration and the state of acid-base balance upon the intrarenal distribution and urinary clearance of the semisynthetic penicillin amdinocillin. Renal physiologic activity significantly modulates the intrarenal distribution pattern of this compound. During the production of maximally acid and concentrated urine, the highest renal parenchyma levels of amdinocillin are achieved. During the latter circumstances the antibiotic undergoes distal tubular nonionic diffusion, which appears to be an important contributing factor to the high medullary and papillary concentrations of the drug. Nonetheless, at all levels of tested renal physiologic activity tissue and urine drug concentrations are adequate for the treatment of sensitive urinary pathogens.

A comparative study of Miraxid (pivmecillinam plus pivampicillin) and Augmentin (amoxycillin plus clavulanic acid) in the treatment of lower respiratory tract infections in general practice

Two treatments, pivmecillinam 200 mg plus pivampicillin 250 mg (Miraxid) given twice-daily and amoxycillin 250 mg plus clavulanic acid 125 mg (Augmentin) given three times daily were compared in two parallel groups of 388 general practice patients with acute bronchitis or acute exacerbations of chronic bronchitis. Patients with acute bronchitis (140 on Miraxid, 144 on Augmentin) received a 7-day course of treatment and those with acute exacerbations of chronic bronchitis (55 on Miraxid, 49 on Augmentin) a 10-day course of treatment. Both treatments were equally effective, with 99 (71%) patients with acute bronchitis being successfully treated with Miraxid and 107 (74%) with Augmentin. In acute exacerbations of chronic bronchitis, Miraxid was successful in 29 (53%) patients and Augmentin in 24 (49%) patients. Side-effects were reported by 26 (12%) of patients in both treatment groups. This single blind multicentre general practice study comparing twice-daily Miraxid with 3 times daily Augmentin demonstrated that both treatments were equally effective clinically and equally well tolerated.

Antimicrobial update

New and soon-to-be introduced antimicrobials are reviewed and compared with agents already in use to determine possible therapeutic and/or cost advantages. Drugs discussed are amdinocillin, ticarcillin/clavulanic acid, ceftriaxone, ceftazidime, imipenem/cilastatin, aztreonam, and quinolones.

Antimicrobial prophylaxis of travelers' diarrhea: a selected summary

This paper summarizes the published controlled studies of the prophylaxis of travelers' diarrhea in which the following drugs have been used: neomycin, nonabsorbable sulfonamides, Streptotriad, doxycycline, erythromycin, and mecillinam. These studies have shown that antimicrobial prophylaxis can be highly effective in preventing episodes of travelers' diarrhea. The protection, however, lasts only as long as the drugs are being taken; there is no evidence that subclinical infections occur while the drug is being taken. None of the data suggest that antimicrobial prophylaxis increases the probability of infection with drug-resistant enteric pathogens. In these studies few subjects have experienced adverse drug reactions; however, the number of subjects has been too small to allow determination of accurate incidence data. Antimicrobial prophylaxis for travelers' diarrhea can be effectively and safely used on an individualized basis for persons traveling to areas of high risk.

The effectiveness of a short perioperative course with pivampicillin/pivmecillinam in transurethral prostatic resection: clinical results

In a randomized control study comprising 261 patients undergoing transurethral prostatic resection (TUR), the effect of a short perioperative course with the oral combination of pivampicillin/pivmecillinam (PAPM) was analysed in 129 patients. The study was divided in 2 parts: the first 60 patients received 450 mg and the following 69 patients, 900 mg every 12 h until removal of catheter but not longer than for 1 week. 132 controls received parenterally 1 g of cefotaxime (CFT) daily throughout the study. During the first part of the study the frequency of bacteriuria in the PAPM group was 43% preoperatively and 30% 10 days postoperatively, during the second part 47% and 12%, respectively (p less than 0.025). In the CFT group the frequency of bacteriuria was reduced from 52% preoperatively to 28% postoperatively. The prophylactic effect (i.e. the protection against acquired bacteriuria) was 96% and 92% in the PAPM and the CFT groups, respectively. Preoperative bacteriuria was eliminated in 40% of the patients during first part and 69% during second part in the PAPM group, while corresponding figures were 48% and 46% in the cefotaxime group. There were 2 cases of septicemia and 5 of upper urinary tract infections throughout the study evenly distributed between the two groups. Oral pivampicillin/pivmecillinam 900 mg every 12 h was found to be a good alternative for perioperative antibiotic prophylaxis at TUR.

Therapeutic considerations in using combinations of newer beta-lactam antibiotics

The in vitro activity, pharmacokinetic interactions, and clinical efficacy of newer beta-lactam antibiotic combinations are reviewed. Combinations of beta-lactam antibiotics offer an antimicrobial spectrum similar to that of aminoglycoside-beta-lactam combinations without the renal or eighth cranial nerve toxicity of aminoglycosides. Synergistic activity with beta-lactam combinations is demonstrable in vitro against a wide variety of aerobic gram-negative bacilli, but the frequency, with which it is found is substantially less than for aminoglycoside-beta-lactam combinations. Also, in vitro antagonism can be demonstrated, particularly with combinations containing an agent capable of inducing beta lactamase. Substantial alterations in the pharmacokinetics of cefotaxime and desacetylcefotaxime have been demonstrated by the concomitant administration of mezlocillin or azlocillin. In addition, the clearance of moxalactam has been shown to be reduced by concomitant administration of piperacillin, and the clearance of oxacillin is reduced by concomitant mezlocillin therapy. Dosage reductions of these drugs may be appropriate in certain situations. Several clinical trials comparing therapy with beta-lactam combinations versus aminoglycoside-containing regimens in neutropenic patients have shown no difference in overall efficacy between the two regimens, with the possible exception of infections in persistently granulocytopenic patients and perhaps in patients with Pseudomonas aeruginosa infections. beta-lactam combinations are generally less nephrotoxic, but potentially more costly when newer compounds are included, than amino-glycoside-containing regimens. These beta-lactam combinations should be reserved for use in patients at high risk for aminoglycoside toxicity.

The effectiveness of a short perioperative course with pivampicillin/pivmecillinam in transurethral prostatic resection: bacteriological results

We analysed the bacteriological findings in 261 patients undergoing transurethral prostatic resection (TUR) and receiving either an oral course of pivampicillin/pivmecillinam (PAPM) or parenteral cefotaxime (CFT) in a randomized clinical trial. 123/261 patients had bacteriuria before TUR; 80% of the bacteria were gram-negative strains and 20% gram-positive. 88% of the strains were sensitive to PAPM and 93% to CFT but only 58% to ampicillin. The sensitivity of recurring bacteria was not influenced by the short course of PAPM or CFT. The faecal flora was influenced by the treatment with PAPM in terms of growth of Pseudomonas aeruginosa and fungi in some patients, but no resistant strains of Enterobacteriaceae were observed. The peak serum concentrations of ampicillin and mecillinam were obtained 2 hours after intake of the drug and were 4.5 micrograms/ml and 1.7 micrograms/ml respectively. The prostate tissue concentration of ampicillin and mecillinam (AM) was low.

The combination of pivampicillin and pivmecillinam versus pivampicillin alone in the treatment of acute pyelonephritis

96 patients with clinical symptoms of acute pyelonephritis were randomized to 2 weeks treatment with either a fixed combination of pivampicillin and pivmecillinam or to pivampicillin alone. If needed, treatment was first started with the respective parenteral equivalents of the drugs. Acute pyelonephritis was bacteriologically verified in 57 patients, in whom Escherichia coli was isolated in 80% of the cases, Klebsiella in 7% and Proteus mirabilis in 5%. 22 of the 39 patients excluded did not have significant bacteriuria (less than 10(8) c.f.u./l). Combination treatment was superior to pivampicillin/ampicillin alone, in terms of clinical effect, with successful treatment being noted in 93% in the combination group and in 53% in the ampicillin group (p = 0.002). The combination was also more effective bacteriologically and it did not select resistant strains in the urinary tract. Ampicillin treatment alone, was, however, associated with a significant increase in urinary strains resistant to ampicillin and to mecillinam. Unsuccessful responders had a significantly higher mean age (p less than 0.01) than successful responders. No serious side-effects were noted.

[Comparative study of the chemotherapeutic effectiveness of mecillinam, ampicillin and their combination in coli bacillary pyelonephritis in rats]

The chemotherapeutic effect of mecillinam and ampicillin was studied comparatively on rats with hematogenic obturation colibacillary pyelonephritis. The antibiotics were administered intragastrically in a dose of 100 mg/kg for 7 days. The treatment was started 24 hours after infection. When the drugs were used in combination their doses were twice as lower. When used alone mecillinam and ampicillin had a significant effect which was practically the same. A marked increase in the therapeutic effect was observed with the use of the antibiotics in combination: sterilization of the tissues of the affected kidney and prevention of development of macroscopic lesions in it in all the animals.

Nalidixic acid and pivmecillinam for treatment of acute lower urinary tract infections

Women, 15-45 years of age, with symptoms of lower urinary tract infection (UTI) were randomly treated with nalidixic acid (1 g X 3) or pivmecillinam (200-400 mg X 3) for three or seven days, respectively. Therapeutic failure, relapse, or reinfection occurred among 18% of 82 women, even though the isolated strains of gram-negative rods in these patients were susceptible in vitro to the antibiotics used. Therapeutic failure, i.e. no effect or at best only a minor effect on the symptoms, was registered in 10 of 13 cases of UTI caused by Staphylococcus saprophyticus and treated with nalidixic acid, which was consistent with the high minimum inhibitory concentrations (MIC) (128-512 micrograms/ml) of this antibiotic. S. saprophyticus was isolated in 9 of 12 patients during treatment with nalidixic acid. On the other hand, pivmecillinam therapy was clinically effective in 16 of 18 patients with UTI caused by S. saprophyticus, even though the MIC of mecillinam to these strains was considerably higher (8-64 micrograms/ml) than that vis-à-vis gram-negative rods. Thus the clinical effect of pivmecillinam was significantly better than that of nalidixic acid in cases of UTI caused by S. saprophyticus. The organism was not isolated from 14 patients receiving pivmecillinam therapy.

Comparison of long-term, low-dose pivmecillinam and nitrofurantoin in the control of recurrent urinary tract infection in children. An open, randomized, cross-over study

Thirty-five children with a history of vesicoureteric reflux or with recurrent urinary tract infections were randomly allocated to low-dose prophylactic treatment with pivmecillinam or nitrofurantoin. After 6-10 months they were crossed over to the alternate drug for another 6 months, but only 24 completed the study because of lack of compliance or intolerance to nitrofurantoin. There was no significant difference in the long-term prophylactic effect between the two drugs, the overall infection rate being 0.7/patient-year. Pivmecillinam was significantly better tolerated than nitrofurantoin (P = 0.01). Nitrofurantoin effected no major change in the faecal flora, and nearly all urinary infections occurring during long-term treatment were caused by Escherichia coli. In contrast, a marked reduction of E. coli and a marked increase in Gram-positive cocci were found in the faecal flora during treatment with pivmecillinam. Seventy per cent of infections were caused by Streptococcus faecalis and only 20% by E. coli during pivmecillinam treatment (P = 0.001).

Management of typhoid

Typhoid fever is still a major problem in developing Third World countries where socioeconomic conditions and standards of hygiene are still well below standard. Prophylaxis is far from satisfactory. However, recent developments using live oral vaccines are encouraging. Specific treatment for the disease consists of chloramphenicol or co-trimoxazole; amoxycillin and ampicillin are inferior agents but are of value in several situations because their potential toxic effects are less marked. Most other agents also have drawbacks or are relatively ineffective. In the severely toxic patient, corticosteroids seem to affect prognosis favourably. Of the many other acute complications of typhoid fever, ileal perforation is the most serious; there is still controversy concerning the respective roles of conservative and surgical management, but it is clear that individual cases must be assessed on their merit. Amoxycillin, because it is very rapidly absorbed and produces very high blood concentrations, is probably the best antibiotic for the carrier state.

A clinical comparison of pivmecillinam plus pivampicillin (Miraxid) and a triple tetracycline combination (Deteclo) in respiratory infections treated in general practice

Seven-day courses of either pivmecillinam 200 mg plus pivampicillin 250 mg (Miraxid) or a combination of tetracycline hydrochloride, chlortetracycline hydrochloride and demeclocycline hydrochloride (Deteclo) 300 mg, both given twice daily, were compared in a multicentre general practice study in 408 patients with symptoms of upper or lower respiratory tract infection. Patients were stratified into four diagnostic groups: sinusitis, otitis media, throat infections, and acute bronchitis and randomly allocated to treatment within these groups. Assessment at 7 days showed no difference in clinical efficacy between the two treatments where 193 of the 208 infections receiving Miraxid (93%) were rated as either cured or improved compared with 181 of the 201 infections treated with Deteclo (90%). At 7 days, the percentage of patients completely free of symptoms was the same for both groups (66%). The mean time for symptoms to clear was 3.9 days in the Miraxid group and 4.0 days in the Deteclo group. Side-effects were reported by significantly fewer patients in the Miraxid group (9.3%) than the Deteclo group (17.5%) (p less than 0.05) and six patients in the latter group failed to complete the course of treatment. Miraxid given twice daily for respiratory tract infections is as effective as Deteclo but causes significantly fewer side-effects.

A multi-centre general practice clinical evaluation of pivmecillinam plus pivampicillin ('Miraxid') and co-trimoxazole ('Septrin') in respiratory tract infections

Seven-day courses of either 200 mg pivmecillinam plus 250 mg pivampicillin or co-trimoxazole (800 mg sulphamethoxazole plus 160 mg trimethoprim) given twice daily were compared in a multi-centre general practice study in 318 patients with signs and symptoms of upper or lower respiratory tract infection. Patients were stratified into four diagnostic groups (sinusitis, otitis media, throat infections, and acute bronchitis) and randomly allocated to treatment within these groups. Assessments at Day 7 showed that both treatments were equally effective clinically, 154 (91%) patients in the pivmecillinam plus pivampicillin group showing clinical cure or improvement and 142 (88%) patients in the co-trimoxazole group. Side-effects were reported by 19 (11.9%) patients in the pivmecillinam plus pivampicillin group and by 24 (15.8%) patients in the co-trimoxazole group. Two patients in the pivmecillinam plus pivampicillin group and 4 patients in the co-trimoxazole group stopped treatment.

Changes during travel in the composition and antibiotic resistance pattern of the intestinal Enterobacteriaceae flora: results from a study of mecillinam prophylaxis against travellers' diarrhoea

A randomized double-blind study was carried out in a group of Danish students visiting Mexico for 2 weeks to investigate the efficacy of mecillinam when given orally in preventing travellers' diarrhoea. The subjects took either 200 mg mecillinam daily as a single dose or placebo for 14 days. Nine (56%) out of 16 taking placebo and 3 (19%) out of 16 taking mecillinam developed travellers' diarrhoea (p less than 0.05). The pathogenic aetiology was not ascertained. A complete change in the Enterobacteriaceae flora took place during travel. A highly antibiotic-resistant Enterobacteriaceae flora was acquired in Mexico in subjects on mecillinam prophylaxis as well as on placebo. Selection of mecillinam-resistant bacteria was minimal.

Amdinocillin: a novel penicillin. Antibacterial activity, pharmacology and clinical use

Amdinocillin is a novel penicillin whose antibacterial activity is derived from its ability to bind specifically and avidly to Penicillin Binding Protein-2 (PBP 2). Other beta-lactams bind almost exclusively to PBPs 1 and 3. This unique feature has prompted many investigators to predict that amdinocillin would aggressively synergize with other antimicrobials, particularly other beta-lactams. Certain features of these predictions have been realized. Amdinocillin is active alone against many gram-negative organisms. Pseudomonas and non-fermenting gram-negative bacteria, however, are usually resistant. Amdinocillin, in combination with many beta-lactams, exhibits marked synergy against many enterobacteriaceae. No such synergy can be demonstrated for gram-positive organisms or pseudomonas species. Amdinocillin is not beta-lactamase stable. Organisms which produce high levels of plasma-mediated beta-lactamase are resistant to the drug. Amdinocillin is widely distributed to most tissues of the body. It is removed by renal tubular secretion which results in prodigious levels of the drug in the urine. Co-administration of probenecid results in markedly elevated plasma levels of amdinocillin and delays its excretion. Amdinocillin has a plasma half-life of about one hour in patients with grossly normal renal function. Its half-life increases to 3 to 6 hours in anephric patients. The spectrum of adverse reactions observed with amdinocillin is similar to that of other penicillins. Amdinocillin, as a single agent, is effective in the treatment of urinary tract infections caused by susceptible strains of E. coli and klebsiella and enterobacter species. When amdinocillin is used in concert with other antimicrobials, synergy can frequently be demonstrated but it is essentially limited to gram-negative aerobic organisms. At present, insufficient data are available to precisely profile the utility of amdinocillin, either alone or in combination, in the treatment of systemic infections.

[Travellers' diarrhea. Current data on the role of enterotoxigenic Escherichia coli]

50 to 70% of diarrheas contracted during travel in hot countries are due to an enterotoxigenic E. coli having the dual acquired ability to adhere to the intestinal epithelium and to produce an enterotoxin. This produces a liquid diarrhea, usually banal for the traveller but which can sometimes be serious in young children of developing nations. The genes coding for the above two characteristics are carried by a plasmid. Other colibacilli, enteropathogenic or entero-invasive, can also cause diarrhea; being liquid in the former case and dysenteriform in the latter. Other bacteria such as the vibrions and perhaps Aeronomonas, can also secrete an enterotoxin. The role of invasive organisms and viruses is briefly discussed. The prophylaxis is fairly illusive and treatment of the mild forms is usually symptomatic.

A comparison of pivmecillinam/pivampicillin and co-trimoxazole in hospitalized patients with acute exacerbations of chronic bronchitis

Forty-nine hospitalized patients with acute exacerbations of chronic bronchitis were randomly allocated a ten-day course of either pivmecillinam/pivampicillin or co-trimoxazole. Both treatments were equally effective clinically (pivmecillinam/pivampicillin successful in 72% of cases; co-trimoxazole in 70%) and in their ability to eradicate pus from sputum (pivmecillinam/pivampicillin 84%; co-trimoxazole 74%). One patient taking co-trimoxazole ceased therapy because of persistent nausea and vomiting. No side-effects were observed in the pivmecillinam/pivampicillin group.

Pivmecillinam, co-trimoxazole and oral mecillinam in gastroenteritis due to Vibrio spp

The comparative efficacy of antibacterial therapy with pivmecillinam or cotrimoxazole and general supportive care only was studied in patients with severe bacterial gastroenteritis. Overall, treatment with antibiotics proved significantly superior to rehydration alone in 42 children. Active therapy also had a statistically beneficial effect in children infected with Vibrio cholerae and V. parahaemolyticus. Pivmecillinam and co-trimoxazole were equally effective. Pivmecillinam and oral mecillinam appeared to be of equal value in a further 22 adults infected by Vibrio spp. No side-effects were recorded in any of the subjects treated. Further investigations with pivmecillinam and oral mecillinam are advocated.