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Karen Rønø Thingholm,1 Frederik Boëtius Hertz,1,2 Anders Løbner-Olesen,3 Niels Frimodt-Møller,1 Karen Leth Nielsen11Department of Clinical Microbiology, Rigshospitalet, Copenhagen 2100, Denmark; 2Department of Clinical Microbiology, Herlev and Gentofte Hospital, Herlev 2730, Denmark; 3Department of Biology, Section for Functional Genomics and Center for Bacterial Stress Response and Persistence, University of Copenhagen, Copenhagen, DenmarkBackground: Extended spectrum beta-lactamase (ESBL)-producing Escherichia coli (E. coli) causing urinary tract infections often belong to sequence type 131 (ST131), serotype O25, carrying blaCTX-M-15.Aim: The main aim of this study was to examine the conjugational frequencies of E. coli with plasmids carrying blaCTX-M-15 to E. coli isolates from the fecal flora of healthy humans to determine whether ST131 is more likely to uptake or donate ESBL resistance compared to other E. coli clones.Methods: Donors and recipients were all clinical isolates and did not harbor plasmids with identical incompatibility groups (Inc-groups) based on in silico analyses of Inc-groups and restriction/modification systems (R/M-systems). The in vitro conjugation experiments were performed as filter conjugation with verification of transconjugants by random amplified polymorphic DNA (RAPD) PCR and blaCTX-M-15 PCR.Results: The frequencies of conjugation with blaCTX-M-15-carrying plasmids were found to be very rare with detectable conjugation frequencies in the range of 4x10−9–7x10−7 transconjugants/recipient. Recipients of O25/ST131 type yielded significantly lower conjugation frequencies compared to recipients of other O-types (P=0.004). The applied ST131/O25 donors did not yield detectable levels of transconjugants regardless of the applied recipient. Presence of sub-MIC levels of ampicillin increased plasmid transfer frequencies x100 fold (P=0.07).Conclusion: The results indicate that blaCTX-M-15 is rarely transferred by conjugation to E. coli isolates of the intestinal flora, even when the gene is plasmid-borne.Keywords: horizontal gene transfer, antimicrobial resistance, Escherichia coli, molecular typing, ST131, faecal isolates

Filip Jansåker,1,2 Jonas Bredtoft Boel,3 Sara Thønnings,1,2 Frederik Boëtius Hertz,3 Katrine Hartung Hansen,2 Niels Frimodt-Møller,2 Jenny Dahl Knudsen1,21Department of Clinical Microbiology, Hvidovre Hospital, University of Copenhagen, 2650 Hvidovre, Denmark; 2Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; 3Department of Clinical Microbiology, Herlev and Gentofte Hospital, University of Copenhagen, 2730 Herlev, DenmarkObjectives: To compare the therapeutic effect of pivmecillinam and other common oral antibiotics for community-acquired urinary tract infections (UTIs) caused by Extended Spectrum Beta-Lactamase (ESBL)- or non-ESBL-producing Escherichia coli.Methods: Retrospective cohort study from 2010 to mid-2016 with data from the regional Laboratory Database and three national databases on antibiotic prescriptions, hospital admission, and mortality, respectively. Primary care patients (≥18 years) empirically treated for UTI caused by non-ESBL- or ESBL-producing E. coli (non-ESBL and ESBL E. coli) were included. Seven antibiotics, commonly used empirically for UTI, were investigated. Treatment failure measured as the redemption of a new antibiotic prescription or admission to hospital due to UTI. Cox proportional hazard ratios and adjusted risk differences along with 95% confidence intervals were calculated for 14 and 30 days, respectively.Results: Thirty-six thousand two hundred and ninety-three (95.7%) and 1624 (4.3%) cases were included in the non-ESBL and ESBL groups, respectively. Male sex, high age, ESBL production, and resistance to empirical therapy were found to independently increase the risk of treatment failure. Compared to pivmecillinam, ciprofloxacin had significantly lower treatment failure for non-ESBL E. coli, but significantly higher treatment failure in ESBL E. coli. There was no significant difference between nitrofurantoin and pivmecillinam.Conclusion: All antibiotics seem to have a higher risk of treatment failure for UTI caused by ESBL-producing E. coli as compared to non-ESBL-producing E. coli. At present, nitrofurantoin and pivmecillinam seem to be the most relevant orally available therapies for E. coli UTI. Local resistance data should guide which of the two that should be the contemporary first-line option. Keywords: UTI, ESBL, E. coli, pivmecillinam, nitrofurantoin, cohort

Filip Jansåker,1,2 Niels Frimodt-Møller,3 Thomas L Benfield,2,4 Jenny Dahl Knudsen1,3 1Department of Clinical Microbiology, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark; 2Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; 3Department of Clinical Microbiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark; 4Department of Infectious Diseases, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark Purpose: The pharmacokinetic properties of mecillinam (MEC) for urinary tract infections are excellent, and the resistance rate in Enterobacteriaceae is low compared to other recommended antibiotics. The oral prodrug pivmecillinam (P-MEC) has been used successfully as first choice for cystitis in the Nordic countries for many years. Norwegian and Danish guidelines also recommend P-MEC for acute uncomplicated pyelonephritis (AUP) and intravenous (IV) MEC for suspected urosepsis (only in Denmark). Here, we wish to present an updated investigation on the clinical data behind these recommendations together with sparse but more current clinical data.Methods: Prospective clinical trials evaluating MEC as monotherapy or in polytherapy with one other beta-lactam (mostly ampicillin [AMP]) for pyelonephritis or bacteremia were reviewed. Outcomes of primary interest were clinical and bacteriological success and relapse, respectively. Search databases used were PubMed, Cochrane Library, and Embase.Results: Twelve clinical studies (1979–2015) were included in this integrated literature review. Clinical success was seen in 38/51 (75%) patients treated with MEC as monotherapy and in 152/164 (93%) patients treated with MEC and one other beta-lactam. Bacteriological success was seen in 35/47 (74%) and 117/167 (70%) patients treated with MEC alone and with one other beta-lactam, respectively. In complicated infections, bacteriological success was much lower. Clinical relapse rate was not well described. Several uropathogenic bacteremia cases were treated successfully with MEC alone (ie, 10/15 [67%] and 13/15 [87%] for clinical and bacteriological success, respectively) or with one other beta-lactam (ie, 57/65 [88%] and 53/63 [84%] for clinical and bacteriological success, respectively). However, data on bacteremia are very sparse. Adverse reactions were few and mild (73/406 [18%]) and primarily seen when AMP was co-administered (69/73 [95%]). No serious adverse reactions were reported.Conclusion: IV MEC or oral P-MEC for 14 days may be suitable for the treatment of AUP and pediatric pyelonephritis. Randomized controlled trials using a single standardized dose of P-MEC compared to other current recommendations are warranted. Similarly, more evidence is required before MEC should be recommended for bacteremia or sepsis due to Enterobacteriaceae. Keywords: pyelonephritis, mecillinam, review, pivmecillinam, amdinocillin

Abstract Background Magnetic Resonance Imaging (MRI) methods were evaluated as a tool for the study of experimental meningitis. The identification and characterisation of pathophysiological parameters that vary during the course of the disease could be used as markers for future studies of new treatment strategies. Methods Rats infected intracisternally with S. pneumoniae (n = 29) or saline (n = 13) were randomized for imaging at 6, 12, 24, 30, 36, 42 or 48 hours after infection. T1W, T2W, quantitative diffusion, and post contrast T1W images were acquired at 4.7 T. Dynamic MRI (dMRI) was used to evaluate blood-brain-barrier (BBB) permeability and to obtain a measure of cerebral and muscle perfusion. Clinical- and motor scores, bacterial counts in CSF and blood, and WBC counts in CSF were measured. Results MR images and dMRI revealed the development of a highly significant increase in BBB permeability (P < 0.002) and ventricle size (P < 0.0001) among infected rats. Clinical disease severity was closely related to ventricle expansion (P = 0.024). Changes in brain water distribution, assessed by ADC, and categorization of brain 'perfusion' by cortex ΔSI(bolus) were subject to increased inter-rat variation as the disease progressed, but without overall differences compared to uninfected rats (P > 0.05). Areas of well-'perfused' muscle decreased with the progression of infection indicative of septicaemia (P = 0.05). Conclusion The evolution of bacterial meningitis was successfully followed in-vivo with MRI. Increasing BBB-breakdown and ventricle size was observed in rats with meningitis whereas changes in brain water distribution were heterogeneous. MRI will be a valuable technique for future studies aiming at evaluating or optimizing adjunctive treatments

Abstract Background Despite bacteraemia is present in the majority of patients with pneumococcal, little is known about the influence of the systemic infection on the meningeal inflammatory response. Methods To explore the role of systemic infection on the meningeal inflammation, experimental meningitis was induced by intracisternal injection of ~1 × 106 CFU Streptococcus pneumoniae, type 3, and the 26 rabbits were either provided with ~1 × 106 CFU S. pneumoniae intravenously at 0 hour ("bacteraemic" rabbits, n = 9), immunized with paraformaldehyde-killed S. pneumoniae for 5 weeks prior to the experiment ("immunized" rabbits", n = 8), or not treated further ("control" rabbits, n = 9). WBC and bacterial concentrations were determined in CSF and blood every second hour during a 16 hours study period together with CSF IL-8 and protein levels. We also studied CSF and blood WBC levels in 153 pneumococcal meningitis patients with and without presence of bacteraemia. Results As designed, blood bacterial concentrations were significantly different among three experimental groups during the 16 hours study period (Kruskal Wallis test, P < 0.05), whereas no differences in CSF bacterial levels were observed (P > 0.05). Blood WBC decreased in bacteraemic rabbits between ~10–16 hours after the bacterial inoculation in contrast to an increase for both the immunized rabbits and controls (P < 0.05). The CSF pleocytosis was attenuated in bacteraemic rabbits as compared to the two other groups between 12–16 hours from time of infection (P < 0.017), despite accelerated CSF IL-8 levels in bacteraemic rabbits. In patients with pneumococcal meningitis, no significant difference in CSF WBC was observed between patients with or without bacteraemia at admission (n = 103, 1740 cells/μL (123–4032) vs. n = 50, 1961 cells/μL (673–5182), respectively, P = 0.18), but there was a significant correlation between CSF and blood WBC (n = 127, Spearman rho = 0.234, P = 0.008). Conclusion Our results suggest that a decrease in peripheral WBC induced by enhanced bacteraemia in pneumococcal meningitis results in an attenuated CSF pleocytosis.

There has been a dramatic increase in the prevalence of antibiotic-resistant bacteria worldwide. In the Scandinavian countries at least 90% of total antibiotic use relates to outpatients and therefore it has become increasingly important to know the antibiotic prescription pattern of general practitioners (GPs) in order to implement and monitor changes in antibiotic prescribing. The aim of the present study was to evaluate the prescription patterns of GPs in Denmark, Norway and Sweden. In order to achieve a reasonable comparison, a questionnaire consisting of 7 case reports concerning upper and lower respiratory tract infections, urinary tract infections and skin and soft tissue infections was sent to 1,000 GPs in the 3 countries. In general, the guidelines for the treatment of bacterial infections in the individual countries were followed by the responders. In all 3 countries, penicillin V was still the drug most frequently used in upper and lower respiratory tract infections. The greatest difference in prescribing patterns among the countries was seen in the treatment of urinary tract infections, recurrent pharyngeal tonsillitis, acute otitis media and acute exacerbation of chronic bronchitis. There were also differences in the dosing regimens, length of treatment and use of diagnostic techniques.

Rosoxacin and cinoxacin, two new compounds structurally related to nalidixic acid, were investigated in dogs. Our primary interest was in the beneficial effects of the two drugs when used in the treatment of urinary tract infections. The distribution of rosoxacin and cinoxacin was investigated in prostatic tissue, prostatic interstitial fluid, and prostatic secretion, and in vaginal and female urethral secretions. Concentrations of both antibiotics were also measured in plasma, various tissues, and spinal fluid. The amounts of rosoxacin and cinoxacin in all tested tissues, fluids, and secretions were in the range of the minimal inhibitory concentrations for most Gram negative organisms found in urinary tract infections. This suggested possible beneficial effects of these drugs when the infection involves the above tissues. Rosoxacin concentration ratios were higher than those of cinoxacin relative to plasma concentration in prostatic, vaginal, and urethral secretions, as well as in prostatic and other tissue. These ratio differences were explained by the different physiochemical properties of the two drugs.

The pharmacokinetics of mezlocillin were examined after single 2- and 4-g intravenous injections to three groups of male patients with creatinine clearances of I >/= 60, II = 21 to 59, and III

Netilmicin and amikacin, two recently developed aminoglycosides, were compared in a prospective, randomized study of 57 male patients with complicated urinary tract infections. Both drugs were administered intramuscularly every 12 h for 7 to 10 days, netilmicin at 2 mg/kg and amikacin at 7.5 mg/kg. The two groups were comparable as to infecting bacteria and underlying pathology of the urinary tract. No patients had indwelling catheters. All microorganisms isolated were sensitive to both antibiotics. A total of 69% of the patients treated with netilmicin and 57% of the patients treated with amikacin were cured of the infection, as defined by a negative culture at 7 days after discontinuation of treatment. No major side effects were recorded, and no significant changes were noted in parameters of renal function. Of the patients treated with amikacin, 21% experienced temporary local pain at the injection site; no such effect was noted in the netilmicin-treated group. Therefore, netilmicin appeared to be as effective and better tolerated than did amikacin in the treatment of complicated urinary tract infection.

Single-dose versus conventional six-day therapy with sulfamethizole for asymptomatic urinary tract infection in pregnant women was investigated in a prospective, randomised open study. During a nine-month period 4,274 pregnant women were screened for significant bacteriuria, which was found in 123 (2.9%), of whom only five had symptoms of urinary tract infection. Seventy-nine of the patients had a second urine culture performed, revealing significant counts of the same bacteria in only 41. These 41 patients were randomly allocated to one of the two treatment groups. Control urine cultures one week and 4-6 weeks after start of treatment revealed the same cure rates of approximately 50% in both groups. Single-dose treatment is not inferior to conventional therapy; future study is needed to find the best single-dose regimen.

The in vitro antibacterial activities of penicillin, ampicillin, piperacillin, azlocillin, vancomycin, erythromycin, clindamycin, gentamicin, streptomycin, cefotaxime, and ceftriaxone against 198 S. faecalis strains were investigated, employing an agar dilution technique. Results were generally in accord with those of other studies. Ampicillin and penicillin showed equal activities. Twenty percent of the strains were resistant to erythromycin, which correlated with resistance to clindamycin. The activity of cefotaxime was fairly good, but the clinical importance of this observation warrants further investigation. Twenty percent showed high-level resistance to streptomycin. High-grade resistance to gentamicin was noted for one isolate only, making gentamicin the first-choice aminoglycoside for combination treatment at present.

Eighty-five rabbits were injected in one knee with Staphylococcus aureus in order to study the time-related changes in untreated septic arthritis up to 3 months. In the synovial membrane a severe release of lysosomal enzymes was observed. The activity was mainly located in and around lining cells and leucocytes in the pannus demonstrating increasing destructive characteristics. This resulted in marginal erosion and undermining of the cartilage border visible from Day 5 continuing gradually to total joint destruction after 5 weeks. The glycosaminoglycan depletion was observed at the surface of the cartilage at Day 2 and was total after 2 weeks. Our infection model should permit comparison of different therapeutic measures.