First Detection and Molecular Analysis of Leishmania infantum DNA in Sand Flies of Kosovo.

Phlebotomine sand flies (Diptera: Psychodidae) are the principal vectors of phleboviruses and Leishmania spp., the causative agents of leishmaniases. The Mediterranean sand fly fauna is diverse, and leishmaniasis, mainly caused by Leishmania infantum, is endemic in the Balkan countries. Despite recent entomological surveys, only some districts of Kosovo have been sampled for sand flies, with no proof/confirmation of L. infantum. This study aimed to gain further insights into the species composition of natural sand fly populations in previously unsampled districts and areas in Kosovo without reports of leishmaniasis and to detect Leishmania DNA in sand flies. A sand fly survey was conducted in 2022 in all seven districts of Kosovo. Collected females were screened for Leishmania DNA by PCR. Positive samples were sequenced and subjected to maximum likelihood analysis with reference sequences for further molecular characterization. The trapping activities at 114 different localities resulted in 3272 caught specimens, comprising seven sand fly species of two genera, namely Phlebotomus neglectus, Ph. perfiliewi, Ph. tobbi, Ph. papatasi, Ph. simici, Ph. balcanicus and Sergentomyia minuta. Leishmania infantum DNA was detected in three individual sand flies of Ph. neglectus and Ph. perfiliewi. This study provides the most extensive sand fly survey in Kosovo and reports the first record of L. infantum DNA in sand flies, indicating autochthonous circulation of L. infantum.

Population pharmacokinetics of meropenem in patients undergoing automated peritoneal dialysis.

BACKGROUND: Meropenem is a second-line agent for the treatment of peritoneal dialysis-associated peritonitis (PD peritonitis), while information on pharmacokinetics (PK) of intraperitoneal (i.p.) meropenem is limited in this patient group. The objective of the present evaluation was to assess a pharmacokinetic rationale for the selection of meropenem doses in automated PD (APD) patients based on population PK modelling. METHODS: Data were available from a PK study in six patients undergoing APD who received a single 500 mg dose of meropenem intravenous or i.p. A population PK model was developed for plasma and dialysate concentrations (n = 360) using Monolix. Monte Carlo simulations were carried out to assess the probability of achieving meropenem concentrations above minimum inhibitory concentrations (MICs) of 2 and 8 mg/L, representing susceptible and less susceptible pathogens respectively, for at least 40% of the dosing interval (T >MIC ≥ 40%). RESULTS: A two-compartment model for each plasma and dialysate concentrations with one transit compartment for the transfer from plasma to dialysate fluid described the data well. An i.p. dose of 250 and 750 mg, for an MIC of 2 and 8 mg/L respectively, was sufficient to attain the pharmacokinetic/pharmacodynamic target (T >MIC ≥ 40%) in more than 90% patients in plasma and dialysate. Additionally, the model predicted that no relevant meropenem accumulation in plasma and/or peritoneal fluid would occur with prolonged treatment. CONCLUSION: Our results suggest that an i.p. dose of 750 mg daily is optimal for pathogens with an MIC 2-8 mg/L in APD patients.

Ecology, seasonality and host preferences of Austrian Phlebotomus (Transphlebotomus) mascittii Grassi, 1908, populations.

BACKGROUND: Sand flies are principal vectors of the protozoan parasites Leishmania spp. and are widely distributed in all warmer regions of the world, including the Mediterranean parts of Europe. In Central European countries, the sand fly fauna is still under investigation. Phlebotomus mascittii, a suspected but unproven vector of Leishmania infantum, is regarded as the most widely distributed species in Europe. However, many aspects of its biology and ecology remain poorly known. The aim of this study was to provide new data on the biology and ecology of Ph. mascittii in Austria to better understand its current distribution and potential dispersal. METHODS: Sand flies were collected by CDC light traps at four localities in Austria for 11 (2018) and 15 weeks (2019) during the active sand fly season. Climatic parameters (temperature, relative humidity, barometric pressure and wind speed) were retrospectively obtained for the trapping periods. Sand flies were identified by a combined approach (morphology, DNA barcoding, MALDI-TOF protein profiling), and blood meals of engorged females were analysed by DNA sequencing and MALDI-TOF mass spectrometry. RESULTS: In total, 450 individuals of Ph. mascittii were caught. Activity was observed to start at the beginning of June and end at the end of August with peaks in mid-July at three locations and early August at one location. Increased activity was associated with relatively high temperatures and humidity. Also, more individuals were caught on nights with low barometric pressure. Analysis of five identified blood meals revealed chicken (Gallus gallus) and equine (Equus spp.) hosts. Sand fly abundance was generally associated with availability of hosts. CONCLUSION: This study reports unexpectedly high numbers of Ph. mascittii at selected Austrian localities and provides the first detailed analysis of its ecology to date. Temperature and humidity were shown to be good predictors for sand fly activity. Blood meal analyses support the assumption that Ph. mascittii feeds on mammals as well as birds. The study significantly contributes to understanding the ecology of this sand fly species in Central Europe and facilitates prospective entomological surveys.

Phlebotomus (Adlerius) simici NITZULESCU, 1931: first record in Austria and phylogenetic relationship with other Adlerius species.

BACKGROUND: Phlebotomine sand flies are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). Information on sand flies in Central Europe is scarce and, to date, in Austria, only Phlebotomus mascittii has been recorded. In 2018 and 2019, entomological surveys were conducted in Austria with the aim to further clarify sand fly distribution and species composition. RESULTS: In 2019, a Ph. simici specimen was trapped in Austria for the first time. Analyses of two commonly used marker genes, cytochrome c oxidase I (coxI) and cytochrome b (cytb), revealed high sequence identity with Ph. simici specimens from North Macedonia and Greece. Phylogenetic analyses showed high intraspecific distances within Ph. simici, thereby dividing this species into three lineages: one each from Europe, Turkey and Israel. Low interspecific distances between Ph. simici, Ph. brevis and an as yet unidentified Adlerius sp. from Turkey and Armenia highlight how challenging molecular identification within the Adlerius complex can be, even when standard marker genes are applied. CONCLUSION: To our knowledge, this study reports the first finding of Ph. simici in Austria, representing the northernmost recording of this species to date. Moreover, it reveals valuable insights into the phylogenetic relationships among species within the subgenus Adlerius. Phlebotomus simici is a suspected vector of L. infantum and therefore of medical and veterinary importance. Potential sand fly expansion in Central Europe due to climatic change and the increasing import of Leishmania-infected dogs from endemic areas support the need for further studies on sand fly distribution in Austria and Central Europe in general.

Integrative Approach to Phlebotomus mascittii Grassi, 1908: First Record in Vienna with New Morphological and Molecular Insights.

Sand flies (Diptera: Psychodidae: Phlebotominae) are blood-feeding insects that transmit the protozoan parasites Leishmania spp. and various arthropod-borne (arbo) viruses. While in Mediterranean parts of Europe the sand fly fauna is diverse, in Central European countries including Austria mainly Phlebotomus mascittii is found, an assumed but unproven vector of Leishmania infantum. To update the currently understudied sand fly distribution in Austria, a sand fly survey was performed and other entomological catches were screened for sand flies. Seven new trapping locations of Ph. mascittii are reported including the first record in Vienna, representing also one of the first findings of this species in a city. Morphological identification, supported by fluorescence microscopy, was confirmed by two molecular approaches, including sequencing and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) protein profiling. Sand fly occurrence and activity were evaluated based on surveyed locations, habitat requirements and climatic parameters. Moreover, a first comparison of European Ph. mascittii populations was made by two marker genes, cytochrome c oxidase subunit 1 (COI), and cytochrome b (cytb), as well as MALDI-TOF mass spectra. Our study provides new important records of Ph. mascittii in Austria and valuable data for prospective entomological surveys. MALDI-TOF MS protein profiling was shown to be a reliable tool for differentiation between sand fly species. Rising temperatures and globalization demand for regular entomological surveys to monitor changes in species distribution and composition. This is also important with respect to the possible vector competence of Ph. mascittii.

Application errors associated with topical treatment of scabies: an observational study.

BACKGROUND: In recent years, there has been a significant increase in scabies infestations throughout German-speaking countries. Given the high frequency of treatment failures, the question arises as to whether topical permethrin treatment is always performed correctly. PATIENTS AND METHODS: Our department uses a fluorescent test cream to teach patients on how to correctly apply topical permethrin. In the context of a prospective observational study of 21 patients, we systematically assessed and analyzed potential application errors. RESULTS: None of the participants succeeded in adequately applying the cream to the entire skin as previously instructed. The median number of regions left untreated was six (minimum: 2; maximum: 18), which included a median body surface area of 6 % (minimum: 2 %; maximum: 30 %). With regard to predilection sites of scabies, the ankles were left untreated in 62 % of cases, followed by the interdigital spaces (toes) (33 %) and the sacral region (24 %). All patients considered the pretreatment training to be very useful. CONCLUSIONS: The present findings clearly demonstrate potential shortcomings when it comes to the application of topical antiscabies treatment. This may provide a (potentially underestimated) explanation for the large number of reports on treatment failures in this regard, which falsely suggest potential treatment resistance.

Compatibility of aztreonam in four commercial peritoneal dialysis fluids.

The preferable route for treatment of peritoneal dialysis related peritonitis remains the intraperitoneal administration of antibiotics admixed to peritoneal dialysis fluids. It is important to know whether the administered drug is compatible with the PD fluids and its container. In the present study the compatibility of aztreonam with four commercial PDFs at storing temperatures and duration representative for storing conditions in the clinical settings was investigated. Aztreonam concentrations were determined using high-performance liquid chromatography. The antimicrobial activity of aztreonam was evaluated using an E. coli diffusion disk inhibition assay and P. aeruginosa time-kill curves. In Extraneal evaluated at 6 °C, 25 °C and 37 °C aztreonam was stable over the whole study period of 14 days and 24 hours, respectively. In Physioneal and Nutrineal aztreonam was stable at 6 °C for up to 14 days. Antimicrobial activity was retained in all PD fluids over the whole study period. Aztreonam remained stable and was compatible with the PD fluids, particularly with Extraneal or Nutrineal, and no compensatory dose adjustment is needed when stored for up to 14 days at refrigeration temperature before use.

Leishmania spp. seropositivity in Austrian soldiers returning from the Kosovo.

Leishmaniasis is a severe vector-borne disease with two main clinical forms, visceral leishmaniasis and cutaneous leishmaniasis. Both forms of leishmaniasis are also endemic in Mediterranean countries including the Balkan region from where mainly visceral leishmaniasis is reported. Austrian soldiers returning from Kosovo were screened for anti-Leishmania antibodies to assess the risk of infection during operations. Anti-Leishmania antibodies were detected in more than 20% of the soldiers investigated, which indicates a considerable risk of infection during missions in this area and thus suggests the application of protective measures.

Low seroprotection rate for meningococcus serogroup C in the adult HIV-1-infected population in Austria.

Current Advisory Committee on Immunization Practices (ACIP) guidelines recommend immunization of all human immunodeficiency virus (HIV)-infected patients against meningitis serotype ACWY due to recent outbreaks of meningitis C in homosexual men in the USA. Implementation of this recommendation in other countries, such as Austria is hindered by the scarce knowledge on the vaccine coverage. In this study the serostatus for meningococcus serogroup C was analyzed in 390 HIV-infected individuals residing in Austria. These individuals were representative for the Austrian HIV cohort regarding sex, age, transmission risk and HIV progression markers. Overall, 73% were on suppressive antiretroviral therapy, the mean CD4 cell count was 599 cells/µl and immunoglobulin G (IgG) seropositivity was 18% for meningococcus serogroup C. Migrants and patients who had acquired an infection via heterosexual intercourse had a higher chance for meningococcus serogroup C seropositivity. Importantly due to the well-preserved immune status of nearly all participants vaccination would be feasible in the majority of the seronegative patients. It is assumed that this measure would largely reduce the number of patients at risk for this vaccine-preventable disease.

Phlebovirus seroprevalence in Austrian Army personnel returning from missions abroad.

BACKGROUND: Phleboviruses are mainly transmitted by sand flies and infections can result in various symptoms, including meningitis and meningoencephalitis. In endemic regions, seroprevalences in humans and animals are high. Military personnel on missions in endemic areas are at increased risk of infection, however, for soldiers from central European countries, data are scarce. The aims of this study were to determine the exposure to phleboviruses of Austrian soldiers returning from missions abroad and to assess potential risk factors. A retrospective serological study was performed with sera of 753 healthy Austrian soldiers returning from missions in Bosnia and Herzegovina (BIH, n = 61), Kosovo (n = 261), Syria (n = 101) and Lebanon (n = 63) and of soldiers prior to their missions (n = 267). RESULTS: Altogether, 119 sera (15.8%, 119/753) were positive for anti-Phlebovirus IgG antibodies, with highest seroprevalences found in soldiers returning from Kosovo (20.69%, 54/261), followed by Syria (17.82%, 18/101), Lebanon (14.29%, 9/63) and BIH (11.48%, 7/61). Of the soldiers tested prior to their missions 11.61% (31/267) were positive. Of the 119 seropositive individuals, 30 (25.2%, 30/119) also had anti-Phlebovirus IgM antibodies. Phlebovirus seropositivity significantly correlated with symptoms of febrile illness during the respective mission (OR: 1.9, 95% CI: 1.1-3.4, P = 0.03) and with Leishmania seropositivity (OR: 2.7, 95% CI: 1.2-5.8, P = 0.009). Also, the outdoor activity "running" during the mission showed a strong trend towards an association with Phlebovirus seropositivity (OR: 1.9, 95% CI: 0.9-4.4, P = 0.08), and seropositivity generally increased with the duration of a mission (OR: 2.5, 95% CI: 0.9-7.5, P = 0.07). CONCLUSIONS: This study indicates that soldiers are exposed to sand flies and at significant risk for Phlebovirus infection during missions in the Mediterranean area and the Middle East. Adequate prevention measures should be applied particularly during vespertine outdoor activities.

Compatibility of ciprofloxacin with commercial peritoneal dialysis solutions.

Intraperitoneal administration of antibiotics together with peritoneal dialysis fluids (PDFs) remains the preferable route for treatment of peritoneal dialysis-related peritonitis. For home based therapy, antibiotic-containing PDFs are stored for up to two weeks and warmed up to body-temperature before administration. The present study investigated the compatibility of ciprofloxacin with five commercial PDFs at refrigeration-temperature, room-temperature and body-temperature. Ciprofloxacin concentrations were determined using high-performance liquid chromatography. Drug-diluent stability was evaluated by measurement of pH-values and visual inspection at each sampling point. The antimicrobial activity of ciprofloxacin was assessed by an E. coli disk diffusion method. Ciprofloxacin was stable at refrigeration-temperature and body-temperature in all PDFs evaluated over the whole study period of 14 days and 24 hours, respectively. At room-temperature, in contrast, ciprofloxacin demonstrated only limited stability in particular when tested in mixed Physioneal. Except for Physioneal 1.36%, no relevant drug adsorption was observed and the antimicrobial activity of ciprofloxacin was found to be preserved in each PDF at each storage condition investigated. Intraperitoneal ciprofloxacin might be used for inpatient and home based therapy of peritoneal dialysis-related peritonitis and no compensatory dose adjustment is needed when stored for up to two weeks at refrigeration-temperature before use.

Emergence of a dalbavancin induced glycopeptide/lipoglycopeptide non-susceptible Staphylococcus aureus during treatment of a cardiac device-related endocarditis.

In the present study, we demonstrated the emergence of dalbavancin non-susceptible and teicoplanin-resistant Staphylococcus aureus small colony variants which were selected in vivo through long-term treatment with dalbavancin. A 36-year-old man presented with a cardiac device-related S. aureus endocarditis and received long-term therapy with dalbavancin. Consecutively, two glycopeptide/lipoglycopeptide susceptible and two non-susceptible S. aureus isolates were obtained from blood cultures and the explanted pacemaker wire. The isolates were characterized by: standard typing methods, antimicrobial susceptibility testing, auxotrophic profiling, proliferation assays, scanning and transmission electron microscopy, as well as whole genome sequencing. The isolated SCVs demonstrated a vancomycin-susceptible but dalbavancin non-susceptible and teicoplanin-resistant phenotype whereof the respective MICs of the last isolate were 16- and 84-fold higher than the susceptible strains. All four strains were indistinguishable or at least closely related by standard typing methods (spa, MLST, and PFGE), and whole genome sequencing revealed only eight sequence variants. A consecutive increase in cell wall thickness (up to 2.1-fold), an impaired cell separation with incomplete or multiple cross walls and significantly reduced growth rates were observed in the present study. Therefore, the mutations in pbp2 and the DHH domain of GdpP were identified as the most probable candidates due to their implication in the biosynthesis and metabolism of the staphylococcal cell wall. For the first time, we demonstrated in vivo induced dalbavancin non-susceptible/teicoplanin resistant, but vancomycin and daptomycin susceptible S. aureus SCVs without lipopeptide or glycopeptide pretreatment, thus, indicating the emergence of a novel lipoglycopeptide resistance mechanism.

Compatibility of linezolid with commercial peritoneal dialysis solutions.

PURPOSE: Results of a compatibility and stability study of linezolid admixed in commercial peritoneal dialysis (PD) solutions stored at various temperatures are reported. METHODS: Test samples were prepared by adding linezolid i.v. injection (2 mg/mL) to infusion bags of 4 PD solutions (Extraneal, Nutrineal, Physioneal 40 Glucose 1.36%, and Physioneal 40 Glucose 2.27%, all from Baxter Healthcare Corporation). Assessments were conducted at various time points during storage of test samples at refrigeration temperature (6 °C) or room temperature (25 °C) for 14 days and at body temperature (37 °C) for 24 hours. Linezolid concentrations over time were determined by high-performance liquid chromatography, physical compatibility was determined by pH measurement and visual inspection, and antimicrobial activity was monitored by a disk diffusion method. The influence of solution warming by heating plate on drug stability was investigated. RESULTS: Linezolid was stable in all tested solutions for 14 days at refrigeration and room temperatures and for 24 hours at body temperature. No linezolid adsorption to container material was detected. There were only minor variations in pH values, and visual inspection revealed no diluent abnormalities. With 1 exception, antimicrobial activity of >90% was retained in all PD solution samples for the duration of the study under all temperature conditions. CONCLUSION: Linezolid injection 2 mg/mL remained stable and was compatible with the PD solutions studied for up to 2 weeks at refrigeration or room temperature and up to 24 hours at body temperature.

Predictors for influenza vaccine acceptance among patients with inflammatory rheumatic diseases.

BACKGROUND: Patients with inflammatory rheumatic diseases are at higher risk for influenza and current guidelines recommend vaccination for this group of patients. The aim of this study was to evaluate the vaccination coverage and predictors for influenza vaccination among patients with inflammatory rheumatic diseases. METHODS: This survey was conducted at the outpatient rheumatology clinic at the Medical University of Vienna between July and October 2017. All patients diagnosed with an inflammatory rheumatic disease and receiving immunosuppressive therapy were asked to complete a questionnaire about their influenza vaccination status for 2016/17. RESULTS: 490 patients with rheumatic diseases completed a questionnaire (33% male, mean age 55.3 years). The influenza vaccination rate for the previous season was 25.3% (n = 124/490). Predictors for a positive influenza vaccination status were higher age (Adjusted Odds Ratio 5.0, 95% Confidence Interval 2.4-10.4) and treatment with biological disease-modifying antirheumatic drugs (AOR 2.0, 95% CI 1.3-3.1). Patients who received a recommendation for influenza vaccination by their general practitioner were significantly more likely to be vaccinated than those who did not (57% vs. 15%, AOR 6.6, 95% CI 4.1-10.8); even more so if they received a recommendation by their rheumatologist (62% vs. 19%, AOR 9.0, 95% CI 4.9-16.5). The main reasons for patients to decline influenza vaccination were fear of side effects (36%), concerns that vaccination might not be effective due to their immunosuppressed condition (38%) or that it might worsen the rheumatic disease (20%). CONCLUSIONS: A moderate influenza vaccination rate of 25.3% was detected among patients with inflammatory rheumatic diseases. Recommendation of the influenza vaccine by a physician exerts the most effective impact on a positive vaccination status.

Dalbavancin for treatment of implant-related methicillin-resistant Staphylococcus aureus osteomyelitis in an experimental rat model.

Dalbavancin is a new semisynthetic lipoglycopeptide with improved antimicrobial activity against various gram-positive pathogens. It demonstrates an extensive plasma half-life which permits outpatient parenteral antimicrobial therapy with weekly intervals and might therefore be an excellent treatment alternative for patients requiring prolonged antimicrobial therapy. The present study investigated dalbavancin monotherapy in an experimental implant-related methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis model. A clinical MRSA isolate and a Kirschner-wire were inserted into the proximal tibia of anaesthetized Sprague-Dawley rats. Four weeks after infection 34 animals were treated over 4 weeks with either dalbavancin (20 mg/kg loading-dose; 10 mg/kg daily), vancomycin (50 mg/kg twice daily) or left untreated. Twenty-four hours after the last treatment dose tibial bones and Kirschner-wires were harvested for microbiological examination. Based on quantitative bacterial cultures of osseous tissue, dalbavancin was as effective as vancomycin and both were superior to no treatment. No emergence of an induced glycopeptide-/lipoglycopeptide- resistance was observed after a treatment period of four weeks with either dalbavancin or vancomycin. In conclusion, monotherapy with dalbavancin was shown to be as effective as vancomycin for treatment of experimental implant-related MRSA osteomyelitis in rats, but both antimicrobials demonstrated only limited efficacy. Further studies are warranted to evaluate the clinical efficacy of dalbavancin for the treatment of periprosthetic S. aureus infections.

Pharmacokinetics of the P-gp Inhibitor Tariquidar in Rats After Intravenous, Oral, and Intraperitoneal Administration.

BACKGROUND AND OBJECTIVE: P-glycoprotein (P-gp), a transmembrane transporter expressed at the blood-brain barrier, restricts the distribution of diverse central nervous system-targeted drugs from blood into brain, reducing their therapeutic efficacy. The third-generation P-gp inhibitor tariquidar (XR9576) was shown to enhance brain distribution of P-gp substrate drugs in humans. Oral bioavailability of tariquidar was found to be low in humans requiring the compound to be administered intravenously, which hinders a broader clinical use. The objective of the present study was to investigate the plasma pharmacokinetics of tariquidar in rats after single intravenous, oral, and intraperitoneal administration. METHODS: Two different tariquidar formulations (A and B) were used, both at a dosage of 15 mg/kg, respectively. Formulation A was a solution and formulation B was a microemulsion which was previously shown to improve the oral bioavailability of the structurally related P-gp inhibitor elacridar in mice. RESULTS: In contrast to human data, the present study found a high bioavailability of tariquidar in rats after oral dosing. Oral bioavailability was significantly higher (p = 0.032) for formulation B (86.3%) than for formulation A (71.6%). After intraperitoneal dosing bioavailability was 91.4% for formulation A and 99.6% for formulation B. CONCLUSION: The present findings extend the available information on tariquidar and provide a basis for future studies involving oral administration of this compound.

Influence of different peritoneal dialysis fluids on the in vitro activity of fosfomycin against Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa.

Peritonitis is still the main infectious complication among patients on peritoneal dialysis. For treatment of peritoneal dialysis-related peritonitis, the intraperitoneal administration of antibiotics admixed to peritoneal dialysis fluids (PDFs) should be preferred. However, the influence of diverse PDFs on the activity of frequently used antibiotics has been investigated insufficiently. Thus, the present study set out to investigate the in vitro activity of fosfomycin against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus in commercially available PDFs. Time-kill curves in four different PDFs (Dianeal®, Extraneal®, Nutrineal®, and Physioneal®) were performed over 24 h with two different concentrations of fosfomycin (150 and 400 mg/L) and without antibiotics as control. Cation-adjusted Mueller Hinton broth (CA-MHB) was used as a comparator solution. In blank PDFs, bacterial growth of each organism evaluated was reduced when compared to CA-MHB. For S. aureus in blank Physioneal®, a reduction under the limit of detection was observed within 24 h. The activity of fosfomycin was reduced in all PDFs when compared to CA-MHB except for P. aeruginosa in Nutrineal® where the activity of fosfomycin was increased when investigated at 400 mg/L. Against E.coli, bactericidal activity was demonstrated in Extraneal®, Nutrineal®, and Physioneal®. Fosfomycin resistance (MIC > 1024 mg/L) was observed for P. aeruginosa in CA-MHB at both concentrations and in Nutrineal® at 150 mg/L. Fosfomycin is active in PDFs particularly against the frequently isolated enterobacterium E. coli. The choice of the respective PDF considerably influences the microbiological outcome in vitro. Further studies are warranted to investigate the clinical relevance of these findings.

Compatibility of Meropenem with Different Commercial Peritoneal Dialysis Solutions.

♦ BACKGROUND: Intraperitoneal administration of antimicrobial agents is recommended for the treatment of peritoneal dialysis (PD)-related peritonitis. For home-based antimicrobial therapy it is common to supply patients with PD fluid bags with admixed antibiotic. Thus, the compatibility of meropenem with different PD fluids (PDFs), namely Extraneal, Physioneal 1.36% and Physioneal 2.27% (all Baxter Healthcare Corp., Deerfield, IL, USA), was investigated under varying storage conditions. ♦ METHODS: Meropenem (Venus Pharma, Werne, Germany) was stored at 6°C and 25°C over 14 days and at 37°C over 24 hours. Drug concentration over time was determined using high performance liquid chromatography, drug activity by a diffusion disk method, diluent stability by visual inspection and drug adsorption was calculated. Blank PD fluids and deionized water were used as comparator solutions. ♦ RESULTS: Compared to water, the stability of meropenem was minimally lower in Extraneal but markedly reduced in both Physioneal solutions. No significant drug adsorption was detected for any PDF investigated. ♦ CONCLUSIONS: Meropenem is stable and compatible with Extraneal and might be stored for up to a week at refrigeration temperature (6°C). A loss of ~20% of meropenem after 2 days at room temperature should be considered. Mixed Physioneal appears not suitable for storage at any temperature after meropenem has been admixed. A considerable drug degradation due to the warming up to body temperature through heating plates should further be taken into account in clinical practice.

Influence of Different Peritoneal Dialysis Fluids on the In Vitro Activity of Cefepime, Ciprofloxacin, Ertapenem, Meropenem and Tobramycin Against Escherichia Coli.

♦ BACKGROUND: Peritonitis is a major problem among patients on peritoneal dialysis (PD). The influence of diverse PD fluids on the activity of frequently used antibiotics has been insufficiently investigated. Thus, the present study set out to investigate the impact of different PD fluids on the activity of cefepime, ciprofloxacin, ertapenem, meropenem, and tobramycin against Escherichia coli. ♦ METHODS: Time-kill curves in 4 different PD fluids (Dianeal PDG4, Extraneal, Nutrineal PD4 and Physioneal 40, all Baxter Healthcare Corp., Deerfield, IL, USA) were performed over 24 hours with 4 different concentrations (1 × minimum inhibitory concentration [MIC], 4 × MIC, 8 × MIC, 30 × MIC) of each antibiotic evaluated and without antibiotics as control. Cation-adjusted Mueller Hinton broth (CA-MHB) was used as comparator solution. ♦ RESULTS: In all PD fluids investigated, bacterial growth and antimicrobial activity of all antibiotics tested was significantly reduced compared with the CA-MHB comparator solution. Except at high concentrations of 30 × MIC, cefepime, ertapenem and meropenem demonstrated a strongly reduced activity in all PD fluids investigated. Ciprofloxacin and tobramycin were highly active and bactericidal in all PD fluids and demonstrated dose-dependent activity. ♦ CONCLUSION: The antimicrobial activity of cefepime, ertapenem and meropenem is limited or even nullified in certain PD fluids in vitro, whereas ciprofloxacin and tobramycin show excellent activity. The choice of PD fluids can impact the activity of antimicrobial agents and might influence microbiological outcome. Further studies are required to verify the clinical relevance of our findings.