Combined Antibiotic Treatment Research Articles

Synergistic efficacy of meropenem, ciprofloxacin and colistin antibiotics against planktonic and biofilm forms of Myroides odoratimimus bacterial isolates

PurposeIn this study, it was aimed to investigate the combined synergistic efficacy of colistin (CT), meropenem (MEM), and ciprofloxacin (CIP) antibiotics on planktonic and biofilm forms in Myroidesodoratimimus strains isolated from various clinical specimens. MethodsAntibiotic susceptibility was determined by the Kirby-Bauer disk diffusion method. In addition, minimum inhibitory concentrations (MIC) of CIP, MEM, and CT were studied using the standardized broth microdilution method. In vitro synergistic activity of antibiotics against M. odoratimimus planktonic bacteria strains was studied by the Micro Broth Checkerboard method. The microtiter plate (MtP) method was used to determine the effectiveness of antibiotics on M. odoratimimus biofilm formation. ResultsA zone of inhibition was not observed against other antibiotics used except amikacin and linezolid in all strains. While CT/MEM and CT/CIP combinations have a synergistic effect on all strains, the combination CIP/MEM has an additive effect. According to the biofilm inhibition results, all three antibiotics inhibited biofilm formation. However, the efficacy of MEM (60.3–76.5%) and CIP (60.2–77.8%) was approximately two times higher than that of CT (25.4–34.5%). In addition, the effectiveness of combinations of antibiotics on biofilm formation was examined and the percentage of inhibition was 30.8% when CT was used alone, while the biofilm inhibition rates of CT/MEM and CT/CIP were 92.4% and 91.7%, respectively. MEM/CIP combination was inhibited biofilm formation by 75.7%. ConclusionsThis study is the first report showing the efficacy of CT, MEM and CIP antibiotics, which are frequently used in clinical practice, in combination on M. odoratimimus planktonic and biofilm forms. The findings of our study are particularly guiding for combined antibiotic treatment options in immunosuppressed patients admitted to an intensive care unit (ICU). The CT/MEM combination is currently used frequently. In addition, these results are important in terms of supporting in vitro that CT/CIP and MEM/CIP combinations can also be used as a treatment option in M. odoratimimus related infections.

Surgical Treatment of Nontuberculous Mycobacterial Pulmonary Disease and a Combination of Nontuberculous Mycobacterium Pulmonary Disease and Pulmonary Tuberculosis

ObjectivesNontuberculous mycobacterial pulmonary disease (NTMPD) is an important health system problem worldwide. Surgical treatment experience is limited, and the safety of such operations is still unclarified. Therefore, improving our knowledge of NTMPD is important. DesignIn this retrospective observational study, we analyzed the medical records of 2,432 patients operated on from January 2011 through December 2017 in our hospital. There were 20 patients with NTMPD in group 1 and 23 patients with combined NTMPD and pulmonary tuberculosis in group 2. Patients received antibiotic treatment before and after surgery as per Russian Federal clinical guidelines and individual drug susceptibility. ResultsPostoperative complications occurred in 2 (10%) cases in group 1 and 4 (17.4%) in group 2, and intraoperative complications occurred in 2 (8.7%) cases in group 2. There was no 30-day mortality in both groups. After 1 year, all 40 traced patients had neither bacterial excretion nor cavities in the lungs. After 3 years and 5 years, the efficacy among 32 and 13 traced patients was 100%, respectively. ConclusionsModern surgery for small NTMPD forms is safe - helping improve outcomes for ineffective antibiotic treatment. Combined surgery and antibiotic treatment are acceptable in both the short and long term.

Establishment of a reliable in-vivo model of implant-associated infection to investigate innovative treatment options

The increasing number of implant-associated infections and of multiresistant pathogens is a major problem in the daily routine. In the field of osteomyelitis, it is difficult to manage a valid clinical study because of multiple influencing factors. Therefore, models of osteomyelitis with a simulation of the pathophysiology to evaluate treatment options for implant-associated infections are necessary. The aim of this study is to develop a standardized and reproducible osteomyelitis model in-vivo to improve treatment options. This study analyses the influence of a post-infectious implant exchange one week after infection and the infection progress afterward in combination with a systemic versus a local antibiotic treatment in-vivo. Therefore, the implant exchange, the exchange to a local drug-delivery system with gentamicin, and the implant removal are examined. Furthermore, the influence of an additional systemic antibiotic therapy is evaluated. An in-vivo model concerning the implant exchange is established that analyzes clinic, radiologic, microbiologic, histologic, and immunohistochemical diagnostics to obtain detailed evaluation and clinical reproducibility. Our study shows a clear advantage of the combined local and systemic antibiotic treatment in contrast to the implant removal and to a non-combined antibiotic therapy. Group genta/syst. showed the lowest infection rate with a percentage of 62.5% concerning microbiologic analysis, which is in accordance with the immunohistochemical, cytochemical, histologic, and radiologic analysis. Our in-vivo rat model has shown valid and reproducible results, which will lead to further investigations regarding treatment options and influencing factors concerning the therapy of osteomyelitis and implant-associated infections.

Changes of Lacrimal Puncta by Anterior Segment Optical Coherence Tomography after Topical Combined Antibiotic and Steroid Treatment in Cases of Inflammatory Punctual Stenosis.

Purpose To evaluate the role of medical treatment and assessing its effect on resolving epiphora and improving punctum size by high resolution AS-OCT imaging comparing punctal parameters in patients before and after treatment with topical combined antibiotic and steroid treatment in cases of inflammatory punctual stenosis. Patients and Methods. Double-blinded controlled randomized study which was conducted on two groups of patients who had acquired punctal stenosis and epiphora presented to Ophthalmology Clinics of Sohag University Hospitals in the period between Jan 2021 and April 2021. The study included 44 eyes of 50 subjects complaining of epiphora. They were divided into two groups, the epiphora group one (EG1) received eye drops containing combination of antibiotics and steroids (orchadexoline eye drops, each ml contains 5 mg chloramphenicol, 1 mg dexamethasone sodium phosphate, 0.25 mg tetryzoline hydrochloride, 2 mg hydroxypropyl methyl cellulose, 10 mg α-tocopherol acetate (vitamin E), and 8 mg macrogol 400), 5 times daily for the first week, three times daily for the next two weeks, and one time daily for another one week. The second epiphora group (EG2) received preservative-free artificial tears (sodium hyaluronate-, polyethylene-, and propylene glycol-based), three times daily for four weeks. The patients were examined before treatment, one week, one month, and one and half months later. Results Both groups were comparable regarding mean age (49 ± 13 vs 53 ± 11 years, P value = 0.2) and sex (males were 38.6% vs 31.8%, female were 61.4% vs 68.2%, P value = 0.6), respectively, with no statistically significant difference between both groups. Both groups were comparable regarding outer punctual diameter and length between the puncti before treatment. Outer punctal diameters were (EG1 228 ± 113 um, EG2 241 ± 115 um, P value = 0.5). Length between the puncti were (EG1 129 ± 73 um, EG2 137 ± 72 um, P value = 0.6). There was marked improvement of the outer punctual diameter (EG1 373 um ± 92 um, EG2 240 ± 109 um, (P value < 0.0001) and length between the puncti (EG1 217 ± 109 um, 136 ± 71 um (P value < 0.0002)) during the follow-up period. EG1 showed more improvement than EG2 when compared during the follow-up period. Conclusions Topical combined antibiotic and steroid treatment was an effective method in treating cases of inflammatory punctual stenosis as found by monitoring of punctal parameter changes by AS-OCT. AS-OCT was found to be a useful method for evaluation of the lacrimal punctal parameters especially with different treatment modalities in epiphora cases.

Superparamagnetic Iron Oxide Nanoparticles Decorated Mesoporous Silica Nanosystem for Combined Antibiofilm Therapy.

A crucial challenge to face in the treatment of biofilm-associated infection is the ability of bacteria to develop resistance to traditional antimicrobial therapies based on the administration of antibiotics alone. This study aims to apply magnetic hyperthermia together with controlled antibiotic delivery from a unique magnetic-responsive nanocarrier for a combination therapy against biofilm. The design of the nanosystem is based on antibiotic-loaded mesoporous silica nanoparticles (MSNs) externally functionalized with a thermo-responsive polymer capping layer, and decorated in the outermost surface with superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs are able to generate heat upon application of an alternating magnetic field (AMF), reaching the temperature needed to induce a change in the polymer conformation from linear to globular, therefore triggering pore uncapping and the antibiotic cargo release. The microbiological assays indicated that exposure of E. coli biofilms to 200 µg/mL of the nanosystem and the application of an AMF (202 kHz, 30 mT) decreased the number of viable bacteria by 4 log10 units compared with the control. The results of the present study show that combined hyperthermia and antibiotic treatment is a promising approach for the effective management of biofilm-associated infections.

Sensitizing and control of colistin-resistant E. coli O157:H7 with bacteriophage application

In these days that we are drifting into the post-antibiotic era, antibiotics called "last-resort" are begun to be used more frequently. Colistin is one of the last-resort antibiotics that act on Gram-negative bacteria. The aim of the study was to investigate antibiotic re-sensitization effect of lytic bacteriophages on colistin resistant E. coli O157:H7 in-vitro. In the study, four E. coli O157:H7 isolates (encoded 25KA, 44RA, 120RA and 168KA) were included. These isolates had different features such as harboring some of the mcr genes but not showing resistance to colistin, or demonstrating resistance to colistin without carrying any mcr genes. A lytic bacteriophage cocktail was prepared with three Myoviridae family member phages. In order to determine the effect of lytic bacteriophage application on the colistin resistance of E. coli O157:H7 strains before, during and after bacteriophage treatment, minimum inhibitory concentrations (MIC) of the isolates were determined by broth microdilution method. The results were interpreted according to EUCAST. According to the results, up to 3.6 log cfu/ml reductions in colistin resistant E. coli O157:H7 were detected within 6h incubation at 23°C. Colistin and phage combination showed synergistic effect. While strains 25KA and 168KA became susceptible to colistin, 44GA and 120RA were totally eliminated. The survivors of the phage treatment were also become sensitive to colistin. Phage-resistant mutants of 25KA and 168KA showed susceptibility to colistin (1 µg/ml and 0.5 µg/ml, respectively). In addition, 44GA and 120GA remained susceptible. The findings of this study highlight that in addition to taking advantage of the lytic activity of phages in biocontrol area, phages also play a major role in re-sensitization to a last-resort antibiotic like colistin. The results show the synergy between phage–antibiotic combination treatment and give the promising idea that this approach has the potential to extend the effective lifetime of antibiotics.

Short-term results of treatment of staphylococcal periprosthetic hip joint infection with combined antibiotics and bacteriophages treatment

Infectious complications after primary implantation of the hip joint are 0.5–3 %, and in the case of re-endoprosthetics, the risk of periprosthetic infection can reach 30 %. Also, we should not forget about the high percentage (16–20 %) of recurrence of periprosthetic infection of the hip joint, which leads to an unsatisfactory result of treatment up to amputation of a limb or even death of the patient. The reasons for the recurrence of the infectious process can be antibiotic resistance and antibiotic tolerance of microorganisms, as well as the ability of microorganisms to form biofilms on implants. In this regard, there is a constant need to search for alternative means of antimicrobial therapy, as well as to select the optimal ways of their delivery and deposition, which is of practical importance when performing surgical interventions in traumatology and orthopedics to protect the implantable structure from possible infection of the surgical site. One of the methods currently available to combat bacterial infections acquired antibiotic resistance and antibiotic tolerance is the use of natural viruses that infect bacterial bacteriophages. The above suggests a more effective suppression of periprosthetic infection, including persisters that deviate from antibiotics. It is, as a rule, associated with biofilms if used in conjunction with antibiotics and phages, when the use of bacteriophages predetermines the effectiveness of treatment. With the use of sensitive bacteriophages in the treatment of periprosthetic infections, a significant (p = 0.030) reduction in the rate of recurrence of infection (from 31 to 4.5 %) was observed. The use of lytic bacteriophages in traumatology and orthopedics is of great interest for phagotherapy of infections caused by antibiotic-resistant and biofilm-forming strains of bacteria. A clinical study using a single-stage surgical revision with simultaneous application of antibiotics and phages in the treatment of deep periprosthesis infection of the hip joint endoprosthesis, followed by 12 months follow-up for periprosthetic infection recurrence, demonstrated the effectiveness of the use of combined antibiotic and bacteriophages treatment.

Divergent Sepsis Pathophysiology in Older Adults.

Significance: Both incidence and mortality rates of sepsis significantly increase with advanced age, and the majority of sepsis patients are late middle-aged or older. With the proportion of older adults rapidly increasing in developed countries, age-dependent sepsis vulnerability is an urgent medical issue. Due to an increasing life expectancy, postsepsis complications and health care costs are expected to increase as well. Recent Advances: Older patients suffer from higher sepsis incidence and mortality rates, likely resulting from frequent comorbidities, increased coagulation, dysgylcemia, and altered immune responses. Critical Issues: Despite a large number of ongoing clinical and basic research studies, there is currently no effective therapeutic strategy targeting older patients with severe sepsis. The disparity between clinical and basic studies is a problem, and this is largely due to the use of animal models lacking clinical relevance. Although the majority of sepsis cases occur in older adults, most laboratory animals used for sepsis research are very young. Further, despite the wide use of combination fluid and antibiotic treatment in intensive care unit (ICU) patients, most animal research does not include such treatment. Future Directions: Because sepsis is a systemic disease with multiple organ dysfunction, combined therapy approaches, not those targeting single pathways or single organs, are essential. As for preclinical research, it is critical to confirm new findings using aged animal models with clinically relevant ICU-like medical treatments. Antioxid. Redox Signal. 35, 1358-1375.

Is combined rather than single antibiotic therapy actually reasonable in patients with acute calculous cholecystitis?

Acute calculous cholecystitis (AC) is a frequently encountered emergency surgery disease and its standard treatment is cholecystectomy. In patients with high risk in surgery, antibiotic treatment (AT) is important. In routine clinical practices, antibiotics are frequently used either as single or in combination in the treatment of AC. This study examined whether or not combined antibiotic treatment (CAT) had superiority over single antibiotic treatment (SAT) in AC. Patients with cholecystitis who received treatment in the period of 2016-2019 were retrospectively examined. The treatment procedures applied, patient findings, and laboratory data were analyzed using relevant statistical software. The patients were categorized into groups based on the treatment approaches applied, and the effects of SAT and CAT on infection parameters were analyzed. In all, 184 patients received treatment for AC, with a mean age of 57.7, and the female-to-male ratio was 77:107. Of these, 139 patients received SAT and 45 received CAT. No significant difference was found in terms of effectiveness between the SAT and CAT in the patients who received early cholecystectomy treatment and those who received medical treatment with noninvasive intervention. In patients with AC, antibiotics are commonly used either as single or in combination for prophylaxis and therapeutic purposes. As no significant difference was observed between single and combined use in terms of treatment effectiveness and hospitalization duration, CAT is not recommended due to its possibility of allergic side effects, toxicity, and cost-increasing effects.

Urinary tract infection by a rare pathogen Cedecea neteri in a pregnant female with Polyhydramnios: rare case report from UAE

BackgroundCedecea neteri is a gram-negative, oxidase-negative bacillus, a rare pathogen. Few reports are emerging globally about its antimicrobial resistance pattern especially in immunocompromised individuals with comorbidities.Case presentationIn this paper, we report the first case of C. neteri causing urinary tract infection in a pregnant woman at a specialty care hospital in the Northern Emirates of Ras al Khaimah, UAE.Discussion and conclusionC. neteri is a rare and unusual pathogen, unlike routine gram-negative urinary tract pathogens from the family of Enterobacteriaceae and therefore may be missed or misidentified by routine laboratories using conventional microbiology identification techniques. Hence, Cedecea infections may be under-reported. Physicians and microbiology technicians must be aware of such a rare pathogen, as most of the isolates are multi-drug-resistant and require combined antibiotic treatment with beta-lactamase inhibitors and hence pose a treatment challenge especially in immunocompromised patients with comorbidities. In recent years, it has been reported as an emerging opportunistic pathogen.

Amikacin liposome inhalation suspension as a treatment for patients with refractory mycobacterium avium complex lung infection

ABSTRACT Introduction: Amikacin liposome inhalation suspension (ALIS) contains amikacin sulfate, an aminoglycoside antibacterial drug. It has been approved in the US as a combined antibiotic treatment for refractory MAC lung disease patients. ALIS, as an inhaled antibiotic, can deliver amikacin to the infected site effectively and reduce systemic toxicity. Areas covered: This article gives a summated review of the pharmacodynamics, pharmacokinetics, therapeutic efficacy, post-marketing surveillance, and regulatory affairs of ALIS as an add-on therapy for MAC lung disease in adults by analyzing data from preclinical studies, clinical trials and original studies. We systematically searched Medline/PubMed through October 2020. Expert opinion: Studies demonstrate that ALIS as an add-on treatment significantly improve the rate of sputum culture conversion in MAC lung disease patients compare to guideline-recommended therapy only. The ALIS treatment showed a similar risk of serious adverse events and a low chance of renal adverse events. However, ALIS was associated with more respiratory adverse events than guideline-recommended therapy only. There was not sufficient data to conclude that ALIS treatment can improve clinical outcomes; however, with the significant improvement in the microbiology outcome in MAC lung disease patients, ALIS showed its potential use as an adjunct treatment for treating MAC lung disease.

Comparison of oral, nebulized and combination antibiotic treatment of Bordetella bronchiseptica in baboons (Papio spp.).

Incidence of Bordetella pertussis, the causative agent of whooping cough, is rising in some global human populations despite high vaccination rates, and significant research is underway to address the issue. Baboons are an established model for pertussis research, but like many mammals, they can be naturally infected with Bordetella bronchiseptica. Because B.bronchiseptica interferes with B.pertussis research, it must be excluded from baboons under consideration for enrollment in pertussis studies. In addition to research-related concerns, B.bronchiseptica can sometimes cause clinical disease in baboons and other nonhuman primates. This study examined the use of antibiotics to clear B.bronchiseptica in naturally infected baboons. Thirty-five juvenile baboons were divided into five treatment groups: oral sulfamethoxazole/trimethoprim (TMS), nebulized gentamicin (gentamicin), combination (TMS+gentamicin) in positive animals, combination (TMS+gentamicin) as a prophylactic in exposed animals and no treatment (control). Combination of oral TMS and nebulized gentamicin given to positive animals was most effective, producing long-term clearance in 11 out of 12 treated animals. To avoid unnecessary use of antibiotics, our primary management strategy is screening and separating to allow natural clearance and limiting exposure to non-infected animals, but this study investigates an antibiotic regimen that could be used in special circumstances.

The effect of prescribing antibiotics with opioids on the development of opioid use disorder: a national database study

The goal of this study was to examine the impact of inpatient- or emergency department- prescribed antibiotic treatment in combination with opioids on the risk of developing opioid use disorder 12 months following discharge from the hospital. The authors conducted a propensity score-matched cohort study with data from the TriNetX Research Network database to identify adult subjects (18–65 years old) with no previous history of an opioid use disorder. Three cohorts were defined for the analyses: subjects who were prescribed an opioid, opioid in combination with an antibiotic, or an antibiotic while in the emergency department or inpatient unit, from the years 2012 to 2018. The diagnosis of an Opioid Related Disorder (F11.10–F11.20) 12 months following discharge from the emergency department or inpatient unit was then observed within the cohorts following the index event as identified by the ICD-10 procedural coding system. Primary analysis (propensity-score matched on age and sex) showed that opioids prescribed in combination with antibiotics had a protective effect against the development of opioid use disorder. This effect was consistent throughout all of the years included in this study with the smallest protective effect observed in 2018 (2012 risk ratio = 1.27 (95% CI: 1.23, 1.32); 2018 risk ratio: 1.03 (95% CI: 1.01, 1.05). These findings suggest that opioids prescribed in combination with antibiotics in the hospital setting are protective against the development of OUD at later time points following hospital discharge.

238 Vaccination with an E. coli F4/F18 Vaccine for the Prevention of F4-ETEC Post-weaning Diarrhea Resulted in Reduced Post-weaning Mortality and Antibiotic Use

Abstract Post-weaning Escherichia coli diarrhea (PWD) remains a major cause of economic losses for the pig industry. PWD, caused by enterotoxigenic E. coli (ETEC), typically provokes mild to severe watery diarrhea between 5–10 days after weaning, which may result in mortality. Most common adhesins in ETEC are F4 and F18 fimbriae. Therapy to combat PWD typically consists of antibiotic treatment in combination with ZnO (3,000 ppm). Recently, an oral live bivalent E. coli F4/F18 vaccine (Coliprotec® F4/F18; Elanco) was approved on the European market, which reduces the impact of PWD provoked by F4-ETEC and F18-ETEC. The objective was to evaluate mortality and antibiotic use following E. coli F4/F18 vaccination under field conditions. A 160-sow farm (weaning at 26 days) with diagnosed problems of PWD due to F4-ETEC was selected. Piglets were vaccinated at 21 days with the oral live bivalent E. coli F4/F18 vaccine. At weaning, no standard group medication (ZnO and antibiotics) was applied for prevention of PWD. Several performance parameters were collected: treatment incidence (TI100), mortality and days in nursery. Vaccination (n = 3 groups) was compared to a historical control (n = 3 groups) Oral E. coli F4/F18 vaccination significantly reduced TI100 (18.6 ± 6.3 days to 2.4 ± 1.9 days; P &amp;lt; 0.05) due to the reduction in days of antimicrobial group treatment. Mortality rate significantly reduced (11.2 ± 2.6% in control to 4.5 ± 1.5% in vaccinated group; P &amp;lt; 0.05) following vaccination. Days in nursery (48.5 ± 0.3 days) remained constant throughout the trial. The results show that live E. coli F4/F18 vaccination against PWD has significantly impacted mortality, in combination with a reduction in medication use. In conclusion, control of PWD through oral vaccination is a successful option in order to prevent piglets from the negative clinical outcomes of F18-ETEC infection during the post-weaning period.

Empiric and Novel Chemotherapeutic Therapy with Combination Antibiotic Treatment in a Child with Facial Cellulitis Secondary to Odontogenic Abscess

Empiric and Novel Chemotherapeutic Therapy with Combination Antibiotic Treatment in a Child with Facial Cellulitis Secondary to Odontogenic Abscess

Evaluating the potential efficacy and limitations of a phage for joint antibiotic and phage therapy of Staphylococcus aureus infections

In response to increasing frequencies of antibiotic-resistant pathogens, there has been a resurrection of interest in the use of bacteriophage to treat bacterial infections: phage therapy. Here we explore the potential of a seemingly ideal phage, PYOSa, for combination phage and antibiotic treatment of Staphylococcus aureus infections. This K-like phage has a broad host range; all 83 tested clinical isolates of S.aureus tested were susceptible to PYOSa Because of the mode of action of PYOSa, S. aureus is unlikely to generate classical receptor-site mutants resistant to PYOSa; none were observed in the 13 clinical isolates tested. PYOSa kills S. aureus at high rates. On the downside, the results of our experiments and tests of the joint action of PYOSa and antibiotics raise issues that must be addressed before PYOSa is employed clinically. Despite the maintenance of the phage, PYOSa does not clear populations of S. aureus Due to the ascent of a phenotyically diverse array of small-colony variants following an initial demise, the bacterial populations return to densities similar to that of phage-free controls. Using a combination of mathematical modeling and in vitro experiments, we postulate and present evidence for a mechanism to account for the demise-resurrection dynamics of PYOSa and S. aureus Critically for phage therapy, our experimental results suggest that treatment with PYOSa followed by bactericidal antibiotics can clear populations of S. aureus more effectively than the antibiotics alone.

The eternal dilemma of antitoxin antibiotics for skin and soft tissue infection.

In standard clinical practice, combined antibiotic treatment is used to treat severe skin and soft tissue infections (SSTIs), whereby one of the drugs is usually a protein synthesis inhibitor antibiotic. However, evidence for this practice is only based on data from 'in vitro' studies, animal models and case reports. There are no randomized controlled trials. In the light of several new drugs marketed for the treatment of these infections, there is a need to revise the state of the art. New reviews and systematic appraisals of the literature exist on the use of protein synthesis inhibitor antibiotics to treat severe SSTI. Several 'in vitro' studies have assessed the efficacy of some of the new drugs. Combination therapy, including an adjuvant protein synthesis inhibitor antibiotic for toxin suppression, should be used both in patients with severe SSTI and in those with moderate infection and risk factors for methicillin-resistant positive- or Panton-Valentine leukocidin positive-Staphylococcus aureus infection.

Establish axenic cultures of armored and unarmored marine dinoflagellate species using density separation, antibacterial treatments and stepwise dilution selection

Academic research on dinoflagellate, the primary causative agent of harmful algal blooms (HABs), is often hindered by the coexistence with bacteria in laboratory cultures. The development of axenic dinoflagellate cultures is challenging and no universally accepted method suit for different algal species. In this study, we demonstrated a promising approach combined density gradient centrifugation, antibiotic treatment, and serial dilution to generate axenic cultures of Karenia mikimotoi (KMHK). Density gradient centrifugation and antibiotic treatments reduced the bacterial population from 5.79 ± 0.22 log10 CFU/mL to 1.13 ± 0.07 log10 CFU/mL. The treated KMHK cells were rendered axenic through serial dilution, and algal cells in different dilutions with the absence of unculturable bacteria were isolated. Axenicity was verified through bacterial (16S) and fungal internal transcribed spacer (ITS) sequencing and DAPI epifluorescence microscopy. Axenic KMHK culture regrew from 1000 to 9408 cells/mL in 7 days, comparable with a normal culture. The established methodology was validated with other dinoflagellate, Alexandrium tamarense (AT6) and successfully obtained the axenic culture. The axenic status of both cultures was maintained more than 30 generations without antibiotics. This efficient, straightforward and inexpensive approach suits for both armored and unarmored dinoflagellate species.

A biomathematical model of immune response and barrier function in mice with pneumococcal lung infection.

Pneumonia is one of the leading causes of death worldwide. The course of the disease is often highly dynamic with unforeseen critical deterioration within hours in a relevant proportion of patients. Besides antibiotic treatment, novel adjunctive therapies are under development. Their additive value needs to be explored in preclinical and clinical studies and corresponding therapy schedules require optimization prior to introduction into clinical practice. Biomathematical modeling of the underlying disease and therapy processes might be a useful aid to support these processes. We here propose a biomathematical model of murine immune response during infection with Streptococcus pneumoniae aiming at predicting the outcome of different treatment schedules. The model consists of a number of non-linear ordinary differential equations describing the dynamics and interactions of the pulmonal pneumococcal population and relevant cells of the innate immune response, namely alveolar- and inflammatory macrophages and neutrophils. The cytokines IL-6 and IL-10 and the chemokines CCL2, CXCL1 and CXCL5 are considered as major mediators of the immune response. We also model the invasion of peripheral blood monocytes, their differentiation into macrophages and bacterial penetration through the epithelial barrier causing blood stream infections. We impose therapy effects on this system by modelling antibiotic therapy and treatment with the novel C5a-inactivator NOX-D19. All equations are derived by translating known biological mechanisms into equations and assuming appropriate response kinetics. Unknown model parameters were determined by fitting the predictions of the model to time series data derived from mice experiments with close-meshed time series of state parameters. Parameter fittings resulted in a good agreement of model and data for the experimental scenarios. The model can be used to predict the performance of alternative schedules of combined antibiotic and NOX-D19 treatment. We conclude that we established a comprehensive biomathematical model of pneumococcal lung infection, immune response and barrier function in mice allowing simulations of new treatment schedules. We aim to validate the model on the basis of further experimental data. We also plan the inclusion of further novel therapy principles and the translation of the model to the human situation in the near future.

Treatment and Outcomes of Children With Febrile Urinary Tract Infection Due to Extended Spectrum Beta-lactamase-producing Bacteria in Europe: TOO CUTE Study.

The prevalence of extended-spectrum beta-lactamase producing Εnterobacteriaceae (ESBL-PE) is increasing globally. ESBL-PE are an important cause of urinary tract infections (UTIs) in children. We aimed to characterize the clinical presentation, treatment and outcomes of childhood UTI caused by ESBL-PE in Europe. Multicenter retrospective cohort study. Children 0 to 18 years of age with fever, positive urinalysis and positive urine culture for an ESBL-PE uropathogen, seen in a participating hospital from January 2016 to July 2017, were included. Primary outcome measure: day of defervescence was compared between (1) initial microbiologically effective treatment (IET) versus initial microbiologically ineffective treatment (IIT) and (2) single initial antibiotic treatment versus combined initial antibiotic treatment. Clinical and microbiologic failure of initial treatment. We included 142 children from 14 hospitals in 8 countries. Sixty-one children had IET and 77 IIT. There was no statistical difference in time to defervescence for effective/ineffective groups (P = 0.722) and single/combination therapy groups (P = 0.574). Two of 59 (3.4%) and 4/66 (6.1%) patients exhibited clinical failure during treatment (P = 0.683) when receiving IET or IIT, respectively. Eight of 51 (15.7%) receiving IET and 6/58 (10.3%) receiving IIT patients (P = 0.568) had recurring symptoms/signs suggestive of a UTI. Recurrence of a UTI occurred 15.5 days (interquartile range, 9.0-19.0) after the end of treatment. Time to defervescence and clinical failure did not differ between IET/IIT groups. Non-carbapenem beta-lactam antibiotics may be used for the empiric treatment of ESBL febrile UTIs, until susceptibility testing results become available.