Single-dose treatment of acute cystitis with fosfomycin tromethamine

Evaluation of Oral Amoxicillin/Clavulanate for Urinary Tract Infections Caused by Ceftriaxone Non-Susceptible Enterobacterales

Urinary tract infections (UTIs) are one of the most common infections and are frequently caused by Gram-negative organisms. The rise of resistant isolates has prompted evaluation of alternative therapies, including amoxicillin-clavulanate which has potent activity against Ambler class A enzymes. This study sought to evaluate clinical outcomes of patients with ceftriaxone non-susceptible UTIs receiving amoxicillin-clavulanate or standard of care (SOC). This was a single-center, retrospective, cohort study of adult patients with urinary tract infections caused by a ceftriaxone non-susceptible pathogen who received amoxicillin-clavulanate or SOC. The primary outcome was clinical failure at 90 days. Secondary outcomes included time to failure, isolation of a resistant organism, and hospital length of stay. Fifty-nine patients met study inclusion: 26 received amoxicillin/clavulanate and 33 received SOC. Amoxicillin-clavulanate recipients did not have higher failure rates compared to SOC recipients. For patients requiring hospital admission, hospital length of stay was numerically shorter with amoxicillin-clavulanate. The frequency of amoxicillin-clavulanate and carbapenem-resistant organisms did not differ significantly between groups. Amoxicillin-clavulanate may be a useful alternative therapy for the treatment of ceftriaxone non-susceptible Enterobacterales UTIs.

Stereospecific Radical-Mediated B12-Dependent Methyl Transfer by the Fosfomycin Biosynthesis Enzyme Fom3

Fom3, the antepenultimate enzyme in the fosfomycin biosynthetic pathway in Streptomyces spp., is a class B cobalamin-dependent radical SAM methyltransferase that catalyzes methylation of (5'-cytidylyl)-2-hydroxyethylphosphonate (2-HEP-CMP) to form (5'-cytidylyl)-2-hydroxypropylphosphonate (2-HPP-CMP). Previously, the reaction of Fom3 with 2-HEP-CMP produced 2-HPP-CMP with mixed stereochemistry at C2. Mechanistic characterization has been challenging because of insoluble expression and poor cobalamin (B12) incorporation in Escherichia coli. Recently, soluble E. coli expression and incorporation of cobalamin into Fom3 were achieved by overexpression of the BtuCEDFB cobalamin uptake system. Herein, we use this new method to obtain Fom3 from Streptomyces wedmorensis. We show that the initiator 5'-deoxyadenosyl radical stereospecifically abstracts the pro- R hydrogen atom from the C2 position of 2-HEP-CMP and use the downstream enzymes FomD and Fom4 to demonstrate that our preparation of Fom3 produces only (2 S)-2-HPP-CMP. Additionally, we show that the added methyl group originates from SAM under multiple-turnover conditions, but the first turnover uses a methyl donor already present on the enzyme; furthermore, cobalamin isolated from Fom3 reaction mixtures contains methyl groups derived from SAM. These results are consistent with a model in which Fom3 catalyzes methyl transfer from SAM to cobalamin and the resulting methylcobalamin (MeCbl) is the ultimate methyl source for the reaction.

A best practice position statement on pregnancy in chronic kidney disease: the Italian Study Group on Kidney and Pregnancy

Pregnancy is increasingly undertaken in patients with chronic kidney disease (CKD) and, conversely, CKD is increasingly diagnosed in pregnancy: up to 3 % of pregnancies are estimated to be complicated by CKD. The heterogeneity of CKD (accounting for stage, hypertension and proteinuria) and the rarity of several kidney diseases make risk assessment difficult and therapeutic strategies are often based upon scattered experiences and small series. In this setting, the aim of this position statement of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology is to review the literature, and discuss the experience in the clinical management of CKD in pregnancy. CKD is associated with an increased risk for adverse pregnancy-related outcomes since its early stage, also in the absence of hypertension and proteinuria, thus supporting the need for a multidisciplinary follow-up in all CKD patients. CKD stage, hypertension and proteinuria are interrelated, but they are also independent risk factors for adverse pregnancy-related outcomes. Among the different kidney diseases, patients with glomerulonephritis and immunologic diseases are at higher risk of developing or increasing proteinuria and hypertension, a picture often difficult to differentiate from preeclampsia. The risk is higher in active immunologic diseases, and in those cases that are detected or flare up during pregnancy. Referral to tertiary care centres for multidisciplinary follow-up and tailored approaches are warranted. The risk of maternal death is, almost exclusively, reported in systemic lupus erythematosus and vasculitis, which share with diabetic nephropathy an increased risk for perinatal death of the babies. Conversely, patients with kidney malformation, autosomal-dominant polycystic kidney disease, stone disease, and previous upper urinary tract infections are at higher risk for urinary tract infections, in turn associated with prematurity. No risk for malformations other than those related to familiar urinary tract malformations is reported in CKD patients, with the possible exception of diabetic nephropathy. Risks of worsening of the renal function are differently reported, but are higher in advanced CKD. Strict follow-up is needed, also to identify the best balance between maternal and foetal risks. The need for further multicentre studies is underlined.

Fosfomycin: An Alternative Therapy for the Treatment of UTI Amidst Escalating Antimicrobial Resistance

INTRODUCTION

Urinary tract infections (UTIs) are the most commonly encountered infectious diseases. The current study was undertaken with a dual purpose, to provide an insight into the current scenario of the microorganisms causing UTI, their antimicrobial sensitivity patterns and also try and evaluate the activity of fosfomycin against E. coli, both ESBL producers as well as non-producers.

MATERIALS AND METHODS

The study was conducted prospectively in the Department of Microbiology of a tertiary care hospital from January to June 2014. A total of 358 isolates from the urinary samples of the patients with a diagnosis of urinary tract infection were included in the study. Antibiotic sensitivity testing and extended spectrum beta lactamase (ESBL) production testing was done as per CLSI guidelines.

RESULTS

These represented 297 (82.9%) gram-negative isolates and 61 (17%) gram-positive isolates. The 297 gram-negative isolates represented 265 (89.2%) members of the Enterobacteriaceae, 185 (69.8%) of which were Escherichia coli, 66 (24.9%) Klebsiella spp. and 14 (5.28%) Proteus spp. Non-fermentative Pseudomonas spp were isolated from 8.9% cases. Amongst the Gram negative isolates tested, 78 (21.8%) formed extended spectrum beta-lactamases. Of the total 358 isolates tested, 338 (94.4%) were found to be susceptible to fosfomycin.

CONCLUSION

Fosfomycin showed good activity against both ESBL-producing and ESBL-negative E. coli isolates. The main finding of our study is that fosfomycin exhibits excellent antimicrobial activity even against the isolates with relatively high levels of antimicrobial resistance and hence can be a useful drug in our armamentarium.

Fosfomycin induced structural change in fosfomycin resistance kinases FomA: molecular dynamics and molecular docking studies

Fosfomycin resistance kinases FomA, one of the key enzymes responsible for bacterial resistances to fosfomycin, has gained much attention recently due to the raising public concern for multi-drug resistant bacteria. Using molecular docking followed by molecular dynamics simulations, our group illustrated the process of fosfomycin induced conformational change of FomA. The detailed roles of the catalytic residues (Lys18, His58 and Thr210) during the formation of the enzyme-substrate complex were shown in our research. The organization functions of Gly53, Gly54, Ile61 and Leu75 were also highlighted. Furthermore, the cation-π interaction between Arg62 and Trp207 was observed and speculated to play an auxiliary role in the conformation change process of the enzyme. This detailed molecular level illustration of the formation of FomA·ATP·Mg·Fosfomycin complex could provide insight for both anti-biotic discovery and improvement of fosfomycin in the future.

Evaluation of three-dose fosfomycin tromethamine in the treatment of patients with urinary tract infections: an uncontrolled, open-label, multicentre study

OBJECTIVE

To evaluate the clinical and microbiological efficacy and safety of three doses of 3 g fosfomycin tromethamine administered orally to treat lower urinary tract infections.

DESIGN AND PARTICIPANTS

This prospective, uncontrolled, open-label study was conducted in 12 medical centres in China, between January and December 2011. According to the diagnosis criteria of Chinese Guidelines on Urological Infections, patients (18-70 years) with acute uncomplicated cystitis, recurrent lower urinary tract infection or complicated lower urinary tract infection received three doses of 3 g fosfomycin tromethamine orally, at days 1, 3 and 5.

PRIMARY AND SECONDARY OUTCOME MEASURES

Efficacy endpoints (clinical efficacy, microbiological efficacy and overall efficacy) were evaluated on day 15. Clinical symptoms, physical signs, urinalysis, liver and kidney function, patient records and evaluation of adverse events (AEs) and serious AEs up to day 15 were evaluated for analysis of safety.

RESULTS

361 patients were included in the full analysis set, 356 in the safety analysis set and 335 in the per-protocol set (PPS). In the PPS, the clinical efficacy rates at day 15 for acute uncomplicated cystitis, recurrent lower urinary tract infection and complicated lower urinary tract infection were 94.71% (179/189), 77.22% (61/79) and 62.69% (42/67), respectively. The microbiological efficacy rates (day 15) were 97.65% (83/85), 94.44% (34/36) and 83.87% (26/31), respectively. The overall efficacy rates (day 15) were 95.29% (81/85), 77.78% (28/36) and 64.52% (20/31), respectively. 20/356 (5.6%) patients reported drug-related AEs, the most common being diarrhoea. No serious drug-related AEs were reported.

CONCLUSIONS

This fosfomycin tromethamine dosing regimen showed clinical and microbiological efficacy with some AEs and good tolerability in patients with acute uncomplicated cystitis, recurrent lower urinary tract infection and complicated lower urinary tract infection.

Different biosynthetic pathways to fosfomycin in Pseudomonas syringae and Streptomyces species

Fosfomycin is a wide-spectrum antibiotic that is used clinically to treat acute cystitis in the United States. The compound is produced by several strains of streptomycetes and pseudomonads. We sequenced the biosynthetic gene cluster responsible for fosfomycin production in Pseudomonas syringae PB-5123. Surprisingly, the biosynthetic pathway in this organism is very different from that in Streptomyces fradiae and Streptomyces wedmorensis. The pathways share the first and last steps, involving conversion of phosphoenolpyruvate to phosphonopyruvate (PnPy) and 2-hydroxypropylphosphonate (2-HPP) to fosfomycin, respectively, but the enzymes converting PnPy to 2-HPP are different. The genome of P. syringae PB-5123 lacks a gene encoding the PnPy decarboxylase found in the Streptomyces strains. Instead, it contains a gene coding for a citrate synthase-like enzyme, Psf2, homologous to the proteins that add an acetyl group to PnPy in the biosynthesis of FR-900098 and phosphinothricin. Heterologous expression and purification of Psf2 followed by activity assays confirmed the proposed activity of Psf2. Furthermore, heterologous production of fosfomycin in Pseudomonas aeruginosa from a fosmid encoding the fosfomycin biosynthetic cluster from P. syringae PB-5123 confirmed that the gene cluster is functional. Therefore, two different pathways have evolved to produce this highly potent antimicrobial agent.

Discovery and biosynthesis of phosphonate and phosphinate natural products

The P-C bonds in phosphonate and phosphinate natural products endow them with a high level of stability and the ability to mimic phosphate esters and carboxylates. As such, they have a diverse range of enzyme targets that act on substrates containing such functionalities. Recent years have seen a renewed interest in discovery efforts focused on this class of compounds as well as in understanding their biosynthetic pathways. This chapter focuses on current knowledge of these biosynthetic pathways as well as tools for phosphonate discovery.

Structural and biochemical insights into the mechanism of fosfomycin phosphorylation by fosfomycin resistance kinase FomA

We present here the crystal structures of fosfomycin resistance protein (FomA) complexed with MgATP, with ATP and fosfomycin, with MgADP and fosfomycin vanadate, with MgADP and the product of the enzymatic reaction, fosfomycin monophosphate, and with ADP at 1.87, 1.58, 1.85, 1.57, and 1.85 Å resolution, respectively. Structures of these complexes that approximate different reaction steps allowed us to distinguish the catalytically active conformation of ATP and to reconstruct the model of the MgATP·fosfomycin complex. According to the model, the triphosphate tail of the nucleotide is aligned toward the phosphonate moiety of fosfomycin, in contest to the previously published MgAMPPNP complex, with the attacking fosfomycin oxygen positioned 4 Å from the γ-phosphorus of ATP. Site-directed mutagenesis studies and comparison of these structures with that of homologous N-acetyl-l-glutamate and isopentenyl phosphate kinases allowed us to propose a model of phosphorylation of fosfomycin by FomA enzyme. A Mg cation ligates all three phosphate groups of ATP and together with positively charged K216, K9, K18, and H58 participates in the dissipation of negative charge during phosphoryl transfer, indicating that the transferred phosphate group is highly negatively charged, which would be expected for an associative mechanism. K216 polarizes the γ-phosphoryl group of ATP. K9, K18, and H58 participate in stabilization of the transition state. D150 and D208 play organizational roles in catalysis. S148, S149, and T210 participate in fosfomycin binding, with T210 being crucial for catalysis. Hence, it appears that as in the homologous enzymes, FomA-catalyzed phosphoryl transfer takes place by an in-line predominantly associative mechanism.

Treatments for symptomatic urinary tract infections during pregnancy

BACKGROUND

Urinary tract infections, including pyelonephritis, are serious complications that may lead to significant maternal and neonatal morbidity and mortality. There is a large number of drugs, and combination of them, available to treat urinary tract infections, most of them tested in non-pregnant women. Attempts to define the optimal antibiotic regimen for pregnancy have, therefore, been problematic.

OBJECTIVES

The objective of this review was to determine, from the best available evidence from randomised controlled trials, which agent is the most effective for the treatment of symptomatic urinary tract infections during pregnancy in terms of cure rates, recurrent infection, incidence of preterm delivery and premature rupture of membranes, admission to neonatal intensive care unit, need for change of antibiotic, and incidence of prolonged pyrexia.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (November 2009) and reference lists of articles.

SELECTION CRITERIA

We considered all trials where the intention was to allocate participants randomly to one of at least two alternative treatments for any symptomatic urinary tract infection.

DATA COLLECTION AND ANALYSIS

Both review authors assessed trial quality and extracted data.

MAIN RESULTS

We included 10 studies, recruiting a total of 1125 pregnant women. In most of the comparisons there were no significant differences between the treatments under study with regard to cure rates, recurrent infection, incidence of preterm delivery, admission to neonatal intensive care unit, need for change of antibiotic and incidence of prolonged pyrexia. When cefuroxime and cephradine were compared, there were better cure rates (29/49 versus 41/52) and fewer recurrences (20/49 versus 11/52) in the cefuroxime group. There was only one other statistically significant difference when comparing outpatient versus inpatient treatment. Gestational age at birth was greater in women from the outpatient group (38.86 versus 37.21), while birthweight was on average greater in the inpatient group (3120 versus 2659).

AUTHORS' CONCLUSIONS

Although antibiotic treatment is effective for the cure of urinary tract infections, there are insufficient data to recommend any specific drug regimen for treatment of symptomatic urinary tract infections during pregnancy. All the antibiotics studied were shown to be very effective in decreasing the incidence of the different outcomes. Complications were very rare. All included trials had very small sample sizes to reliably detect important differences between treatments. Future studies should evaluate the most promising antibiotics, in terms of class, timing, dose, acceptability, maternal and neonatal outcomes and costs.

Clinical significance of the pharmacokinetic and pharmacodynamic characteristics of fosfomycin for the treatment of patients with systemic infections

The advancing antimicrobial drug resistance in common bacterial pathogens, along with the relative shortage of new antibacterial agents, call for the re-evaluation of available therapeutic options. Fosfomycin is an established treatment option for uncomplicated urinary tract infections. Here we review and evaluate the main pharmacokinetic and pharmacodynamic parameters of intravenously administered fosfomycin with regard to its use for systemic infections. Fosfomycin is a relatively small, hydrophilic agent with almost negligible serum protein binding. It is excreted unchanged in urine, achieving high concentrations for a prolonged period. Fosfomycin has good distribution into tissues, achieving clinically relevant concentrations in sites such as serum, soft tissue, lungs, bone, cerebrospinal fluid and heart valves. Fosfomycin has shown antimicrobial activity against biofilms, particularly in combination with fluoroquinolones. It also exerts immunomodulatory effects, mainly on lymphocyte and neutrophil function. Potentially useful properties of fosfomycin regarding its use in combination regimens include reduction in the expression of certain penicillin-binding proteins and attenuation of nephrotoxicity caused by several antimicrobial agents. In conclusion, the pharmacokinetic and pharmacodynamic properties of fosfomycin do not preclude its use for various types of systemic infections and suggest further research on relevant clinical applications of this agent.

Susceptibility of urinary tract bacteria to fosfomycin

We evaluated the in vitro activity of fosfomycin against urinary isolates in a region in Greece that exhibits considerable antimicrobial resistance by evaluating retrospectively relevant susceptibility data retrieved from the microbiological library of the University Hospital of Heraklion, Crete, Greece. We examined 578 urinary isolates. In total, 516 (89.2%) were susceptible to fosfomycin; 415 isolates were gram negative, and 101 isolates were gram positive. Fosfomycin appears to exhibit good levels of in vitro activity against the examined urinary isolates.

Biosynthesis of phosphonic and phosphinic acid natural products

Natural products containing carbon-phosphorus bonds (phosphonic and phosphinic acids) have found widespread use in medicine and agriculture. Recent years have seen a renewed interest in the biochemistry and biology of these compounds with the cloning of the biosynthetic gene clusters for several family members. This review discusses the commonalities and differences in the molecular logic that lie behind the biosynthesis of these compounds. The current knowledge regarding the metabolic pathways and enzymes involved in the production of a number of natural products, including the approved antibiotic fosfomycin, the widely used herbicide phosphinothricin (PT), and the clinical candidate for treatment of malaria FR-900098, is presented. Many of the enzymes involved in the biosynthesis of these compounds catalyze chemically and biologically unprecedented transformations, and a wealth of new biochemistry has been revealed through their study. These investigations have also suggested new strategies for natural product discovery.

Crystal structure of fosfomycin resistance kinase FomA from Streptomyces wedmorensis

The fosfomycin resistance protein FomA inactivates fosfomycin by phosphorylation of the phosphonate group of the antibiotic in the presence of ATP and Mg(II). We report the crystal structure of FomA from the fosfomycin biosynthetic gene cluster of Streptomyces wedmorensis in complex with diphosphate and in ternary complex with the nonhydrolyzable ATP analog adenosine 5'-(beta,gamma-imido)-triphosphate (AMPPNP), Mg(II), and fosfomycin, at 1.53 and 2.2 angstroms resolution, respectively. The polypeptide exhibits an open alphabetaalpha sandwich fold characteristic for the amino acid kinase family of enzymes. The diphosphate complex shows significant disorder in loops surrounding the active site. As a result, the nucleotide-binding site is wide open. Binding of the substrates is followed by the partial closure of the active site and ordering of the alpha2-helix. Structural comparison with N-acetyl-L-glutamate kinase shows several similarities in the site of phosphoryl transfer: 1) preservation of architecture of the catalytical amino acids of N-acetyl-L-glutamate kinase (Lys9, Lys216, and Asp150 in FomA); 2) good superposition of the phosphate acceptor groups of the substrates, and 3) good superposition of the diphosphate molecule with the beta- and gamma-phosphates of AMPPNP, suggesting that the reaction could proceed by an associative in-line mechanism. However, differences in conformations of the triphosphate moiety of AMPPNP molecules, the long distance (5.1 angstroms) between the phosphate acceptor and donor groups in FomA, and involvement of Lys18 instead of Lys9 in binding with the gamma-phosphate may indicate a different reaction mechanism. The present work identifies the active site residues of FomA responsible for substrate binding and specificity and proposes their roles in catalysis.

Heterologous production of fosfomycin and identification of the minimal biosynthetic gene cluster

Fosfomycin is a clinically utilized, highly effective antibiotic, which is active against methicillin- and vancomycin-resistant pathogens. Here we report the cloning and characterization of a complete fosfomycin biosynthetic cluster from Streptomyces fradiae and heterologous production of fosfomycin in S. lividans. Sequence analysis coupled with gene deletion and disruption revealed that the minimal cluster consists of fom1-4, fomA-D. A LuxR-type activator that was apparently required for heterologous fosfomycin production was also discovered approximately 13 kb away from the cluster and was named fomR. The genes fomE and fomF, previously thought to be involved in fosfomycin biosynthesis, were shown not to be essential by gene disruption. This work provides new insights into fosfomycin biosynthesis and opens the door for fosfomycin overproduction and creation of new analogs via biomolecular pathway engineering.

The pregnant wilderness traveler

BACKGROUND

Travel during pregnancy, especially, when it involves potentially hazardous activities in remote areas, often raises serious concerns regarding the health and safety risks involved.

METHOD

The authors have researched the available medical literature to identify these risks and present the current recommendations for their prevention and treatment.

RESULTS

Topics addressed include some political and social issues, insurance, basic comfort measures, complications of pregnancy, infectious diseases, environmental exposures, and trauma. Preventive measures include pre-travel evaluation and teaching, possible modifications of the itinerary, vaccinations and medications. Also briefly discussed are the handling of obstetrical emergencies in the field and medical evacuation of the pregnant patient.

CONCLUSIONS

The authors conclude that many trips of this nature can be made relatively safe for the pregnant traveler, but she may need to accept some precautions and modifications of the itinerary that might not otherwise be necessary.

Urinary Tract Infections During Pregnancy

OBJECTIVE

To provide a comprehensive review of urinary tract infections (UTIs) during pregnancy. All aspects of UTIs, including epidemiology, pathogenesis, resistance, clinical features, diagnosis, treatment, and prevention, were reviewed.

DATA SOURCES

MEDLINE (1966–August 2003) and Cochrane Library searches were performed using the key search terms urinary tract infection, pyelonephritis, cystitis, asymptomatic bacteriuria, and resistance.

STUDY SELECTION AND DATA EXTRACTION

All article abstracts were evaluated for relevance. Only articles pertaining to pregnancy were included. The majority of published literature were review articles; the number of original clinical studies was limited.

DATA SYNTHESIS

UTIs are the most common bacterial infections during pregnancy. They are characterized by the presence of significant bacteria anywhere along the urinary tract. Pyelonephritis is the most common severe bacterial infection that can lead to perinatal and maternal complications including premature delivery, infants with low birth weight, fetal mortality, preeclampsia, pregnancy-induced hypertension, anemia, thrombocytopenia, and transient renal insufficiency. Enterobacteriaceae account for 90% of UTIs. The common antibiotics used are nitrofurantoin, cefazolin, cephalexin, ceftriaxone, and gentamicin.

CONCLUSIONS

Therapeutic management of UTIs in pregnancy requires proper diagnostic workup and thorough understanding of antimicrobial agents to optimize maternal outcome, ensure safety to the fetus, and prevent complications that lead to significant morbidity and mortality in both the fetus and the mother.

Treatments for symptomatic urinary tract infections during pregnancy

BACKGROUND

Urinary tract infections, including pyelonephritis, are serious complications that can result in significant maternal and neonatal morbidity and mortality. There is a large number of drugs, and combination of them, available to treat urinary tract infections, most of them tested in non-pregnant women. Attempts to define the optimal antibiotic regimen for pregnancy has, therefore, been problematic.

OBJECTIVES

The objective of this review was to try to determine, from the best available evidence from randomized control trials, which agent is most effective for the treatment of symptomatic urinary tract infections during pregnancy in terms of cure rates, recurrent infection, incidence of preterm delivery and premature rupture of membranes, admission to neonatal intensive care unit, need for change of antibiotic, and incidence of prolonged pyrexia.

SEARCH STRATEGY

The Cochrane Pregnancy and Childbirth Group trials register (January 2003) and reference lists of articles were searched.

SELECTION CRITERIA

All trials were considered where the intention was to allocate participants randomly to one of at least two alternative treatments for any symptomatic urinary tract infection.

DATA COLLECTION AND ANALYSIS

Both reviewers assessed trial quality and extracted data.

MAIN RESULTS

Eight studies were included, recruiting a total of 905 pregnant women. In most of the comparisons there were no significant differences between studied treatments with regard to cure rates, recurrent infection, incidence of preterm delivery and premature rupture of membranes, admission to neonatal intensive care unit, need for change of antibiotic and incidence of prolonged pyrexia. Only when cefuroxime and cephradine were compared, were there better cure rates (29/49 versus 41/52) and less recurrences (20/49 versus 11/52) in the cefuroxime group, but the sample size is insufficient to ensure that differences found in the effect of the drugs were real.

REVIEWER'S CONCLUSIONS

Although antibiotic treatment is effective for the cure of urinary tract infections, there are insufficient data to recommend any specific treatment regimen for symptomatic urinary tract infections during pregnancy. All the antibiotics studied were shown to be very effective in decreasing the incidence of outcomes measured. Complications were very rare. All included trials had very small sample sizes to try to detect important differences between treatments. Future studies should evaluate the most promising antibiotics, in terms of class, timing, dose, acceptability, maternal and neonatal outcomes and costs.

The new antibiotics

It is easy to become overwhelmed by the amount of information available on the new antibiotics and difficult to keep abreast of the appropriate indications for each of them. For most patients with community-acquired infections, the first-line agent is usually not one of the newer agents, but a standard regimen, or at times, no antibiotic at all. The development of resistance is likely to parallel the extent to which these agents are prescribed. They should be used only when standard treatment fails, when compliance with treatment is a real and serious issue, or when the patient has a real allergic reaction to the standard regimen.

Comparison of single-dose fosfomycin and a 7-day course of nitrofurantoin in female patients with uncomplicated urinary tract infection

This multicenter clinical trial compared single-dose fosfomycin tromethamine with a 7-day course of nitrofurantoin for the treatment of acute uncomplicated lower urinary tract infection (UTI) in female patients. Healthy females with symptoms of acute uncomplicated UTI were enrolled in a double-masked, randomized clinical trial. Assessable patients had >10(5) colony-forming units per milliliter of a uropathogen in a clean-voided midstream urine sample. Patients received a single 3-g dose of fosfomycin tromethamine plus 7 days of placebo capsules or a single 3-g dose of placebo plus 7 days of nitrofurantoin monohydrate/macrocrystal 100-mg capsules. Treatment efficacy was assessed by both bacteriologic and clinical response 5 to 11 days after the initial treatment dose (visit 2) and 5 to 11 days (visit 3) and 4 to 6 weeks (visit 4) after the last day of medication. Of the 749 patients initially enrolled in the study, 375 received fosfomycin and 374 received nitrofurantoin. There were no clinical differences in patient characteristics between the 2 groups at study entry. Overall, 94% of pretreatment isolates were susceptible to fosfomycin and 83% were susceptible to nitrofurantoin. Bacteriologic cure rates at the first follow-up visit (5 to 11 days after initiation of treatment) were 78% and 86% for fosfomycin and nitrofurantoin, respectively (P = 0.02). At visit 3 (1 week posttreatment), they were 87% and 81% for fosfomycin and nitrofurantoin, respectively (P = 0.17). Both treatment groups had an 80% overall clinical success rate (cure and improvement). Twenty patients (5.3%) who received fosfomycin and 21 patients (5.6%) who received nitrofurantoin reported an adverse effect related to study medication. The most common side effects related to fosfomycin treatment were diarrhea (2.4%), vaginitis (1.8%), and nausea (0.8%). Both bacteriologic and clinical cure rates observed with a single 3-g dose of fosfomycin were comparable to those achieved with a 7-day course of nitrofurantoin in female patients with acute uncomplicated UTI.

Short-term therapy of acute uncomplicated cystitis

Short-term therapy, including single-dose treatment and up to 3-day courses, can be considered the treatment of choice in premenopausal women with acute uncomplicated cystitis, because of similar effectiveness, better tolerance and compliance, and lower cost as compared with conventional therapy. Several studies with trimethoprim alone or in combination with a sulfonamide, usually sulphamethoxazole, and with fluoroquinolones with moderately long half-lives, such as ciprofloxacin, enoxacin, lomefloxacin and ofloxacin, suggested that results obtained with a single dose may be inferior to those with a 3-day course, and therefore that the latter may be better. Longer therapy was not considered to be necessary. On the other hand, fluoroquinolones with longer half-lives, such as fleroxacin, pefloxacin and rufloxacin, as single-dose therapy may be as effective as other standard regimens. Fosfomycin trometamol may also be suitable for single-dose therapy. Agents that have not been shown effective in any of these short-term regimens should no longer be used for the treatment of acute cystitis.