Clofazimine as a substitute for rifampicin improves efficacy of Mycobacterium avium pulmonary disease treatment in the hollow-fiber model.

Mycobacterium avium complex pulmonary disease is treated with an azithromycin, ethambutol, and rifampicin regimen, with limited efficacy. The role of rifampicin is controversial due to inactivity, adverse effects, and drug interactions. Here, we evaluated the efficacy of clofazimine as a substitute for rifampicin in an intracellular hollow-fiber infection model. THP-1 cells, which are monocytes isolated from peripheral blood from an acute monocytic leukemia patient, were infected with M. avium ATCC 700898 and exposed to a regimen of azithromycin and ethambutol with either rifampicin or clofazimine. Intrapulmonary pharmacokinetic profiles of azithromycin, ethambutol, and rifampicin were simulated. For clofazimine, a steady-state average concentration was targeted. Drug concentrations and bacterial densities were monitored over 21 days. Exposures to azithromycin and ethambutol were 20%-40% lower than targeted but within clinically observed ranges. Clofazimine exposures were 1.7 times higher than targeted. Until day 7, both regimens were able to maintain stasis. Thereafter, regrowth was observed for the rifampicin-containing regimen, while the clofazimine-containing regimen yielded a 2 Log10 colony forming unit (CFU) per mL decrease in bacterial load. The clofazimine regimen also successfully suppressed the emergence of macrolide tolerance. In summary, substitution of rifampicin with clofazimine in the hollow-fiber model improved the antimycobacterial activity of the regimen. Clofazimine-containing regimens merit investigation in clinical trials.

Early Periprosthetic Joint Infections in Total Hip and Knee Arthroplasty: Microorganisms, Mortality, and Implant Survival Using a Combined Dataset from the Dutch Arthroplasty Register and the Dutch National Nosocomial Surveillance Network.

BACKGROUND: Periprosthetic joint infections (PJIs) can lead to higher re-revision rates and even higher mortality rates that may be associated with the responsible microorganism. We evaluated microorganisms that cause early PJIs in primary total hip and knee arthroplasty (THA and TKA), and examined mortality as well as PJI re-revision rates after these PJIs, using a combined dataset from the Dutch Arthroplasty Register (LROI) and the Dutch National Nosocomial Surveillance Network (PREZIES). Secondly, the most common microorganisms that cause PJIs were described according to patient and implant survival. METHODS: We included all PREZIES-confirmed PJIs (n = 1,648) from the combined dataset in which primary THAs and TKAs (2012 to 2018) from the LROI and PREZIES were case-level matched. Kaplan-Meier survival analyses were performed to determine mortality and PJI re-revision rates following PJI revision. RESULTS: The most prevalent microorganism in THAs and TKAs was Staphylococcus aureus (THA 34%; TKA 39%), followed by Coagulase-negative staphylococci (CoNS) (THA 20%; TKA 19%), with Staphylococcus epidermidis (THA 12%; TKA 11%) as the most common subtype, and Enterococcus species (THA 8.6%; TKA 5.9%). The 5-year mortality was 15% (95% confidence interval [CI]: 13 to 18) and 18% (CI: 14 to 21) for THA and TKA patients, respectively. The 5-year PJI re-revision rate was 28% (CI: 24 to 34) for THAs and 30% (CI: 24 to 38) for TKAs. In deceased THA patients who had a PJI, Enterococcus species (14%) were more often registered as microorganisms responsible for the PJI than S. epidermidis (8.5%). CONCLUSION: Over half of the early PJIs in THAs and TKAs in the Netherlands were caused by Staphylococcus aureus and CoNS including Staphylococcus epidermidis. Both 5-year mortality and PJI re-revision rates following PJI were relatively high.

Genomic characterization of methicillin-susceptible Staphylococcus aureus carriage in patients on home parenteral nutrition and their caregivers.

In this prospective study, patients on home parenteral nutrition were twice as likely to be colonized with Staphylococcus aureus if their caregivers were also carriers. Among S. aureus-positive patients and their caregivers, molecular analysis showed 68% genetically related strains. Despite decolonization, genetically related strains reappeared in 70% of patients.

Rectal Culture-Based Versus Empirical Antibiotic Prophylaxis to Prevent Infectious Complications in Men Undergoing Transrectal Prostate Biopsy: A Randomized, Nonblinded Multicenter Trial.

BACKGROUND: An increase in infections after transrectal prostate biopsy (PB), related to an increasing number of patients with ciprofloxacin-resistant rectal flora, necessitates the exploration of alternatives for the traditionally used empirical prophylaxis of ciprofloxacin. We compared infectious complication rates after transrectal PB using empirical ciprofloxacin prophylaxis versus culture-based prophylaxis. METHODS: In this nonblinded, randomized trial, between 4 April 2018 and 30 July 2021, we enrolled 1538 patients from 11 Dutch hospitals undergoing transrectal PB. After rectal swab collection, patients were randomized 1:1 to receive empirical prophylaxis with oral ciprofloxacin (control group [CG]) or culture-based prophylaxis (intervention group [IG]). Primary outcome was any infectious complication within 7 days after biopsy. Secondary outcomes were infectious complications within 30 days, and bacteremia and bacteriuria within 7 and 30 days postbiopsy. For primary outcome analysis, the χ2 test stratified for hospitals was used. Trial registration number: NCT03228108. RESULTS: Data from 1288 patients (83.7%) were available for analysis (CG, 652; IG, 636). Infection rates within 7 days postbiopsy were 4.3% (n = 28) (CG) and 2.5% (n = 16) (IG) (P value = .08; reduction: -1.8%; 95% confidence interval, -.004 to .040). Ciprofloxacin-resistant bacteria were detected in 15.2% (n = 1288). In the CG, the presence of ciprofloxacin-resistant rectal flora resulted in a 6.2-fold higher risk of early postbiopsy infection. CONCLUSIONS: Our study supports the use of culture-based prophylaxis to reduce infectious complications after transrectal PB. Despite adequate prophylaxis, postbiopsy infections can still occur. Therefore, culture-based prophylaxis must be weighed against other strategies that could reduce postbiopsy infections. Clinical Trials Registration. NCT03228108.

The role of rifampicin within the treatment of Mycobacterium avium pulmonary disease.

Rifampicin is recommended for the treatment of Mycobacterium avium complex pulmonary disease alongside azithromycin and ethambutol. We evaluated the azithromycin-ethambutol backbone with and without rifampicin in an intracellular hollow fiber model and performed RNA sequencing to study the differences in adaptation. In an in vitro hollow fiber experiment, we simulated epithelial lining fluid pharmacokinetic profiles of the recommended 3-drug (rifampicin, ethambutol, and azithromycin) or a 2-drug (ethambutol and azithromycin) treatment. THP-1 cells infected with M. avium ATCC700898 were exposed to these regimens for 21 days. We determined intra- and extra-cellular bacterial load- and THP-1 cell densities on days 0, 3, 7, 14, and 21, alongside RNA sequencing. The emergence of macrolide resistance was studied by inoculating intra- and extra-cellular fractions of azithromycin-containing Middlebrook 7H10 agar plates. Complete pharmacokinetic profiles were determined at days 0 and 21. Both therapies maintained stasis of both intra- and extra-cellular bacterial populations for 3 days, whilst regrowth coinciding with the emergence of a macrolide-resistant subpopulation was seen after 7 days. THP-1 cell density remained static. Similar transcriptional profiles were observed for both therapies that were minimally influenced by exposure duration. Transcriptional response was slightly larger during 2-drug treatment. Rifampicin did not add to the antimycobacterial effect to the 2-drug therapy or suppression of emergence resistance. RNA transcription was not greatly altered by the addition of rifampicin, which may be due to strong transcriptional influence of azithromycin and host cells. This questions the role of rifampicin in the currently recommended therapy. These findings should be confirmed in clinical trials.

MGIT Enriched Shotgun Metagenomics for Routine Identification of Nontuberculous Mycobacteria: a Route to Personalized Health Care.

Currently, nontuberculous mycobacteria (NTM) are identified using small genomic regions, and species-level identification is often not possible. We introduce a next-generation sequencing (NGS) workflow that identifies mycobacteria to (sub)species level on the basis of the whole genome extracted from enriched shotgun metagenomic data. This technique is used to study the association between genotypes and clinical manifestations to pave the way to more personalized health care. Two sets of clinical isolates (explorative set [n = 212] and validation set [n = 235]) were included. All data were analyzed using a custom pipeline called MyCodentifier. Sequences were matched against a custom hsp65 database (NGS-hsp65) and whole-genome database (NGS-WG) created based on the phylogeny presented by Tortoli et al. (E. Tortoli, T. Fedrizzi, C. J. Meehan, A. Trovato, et al., Infect Genet Evol 56:19-25, 2017, https://doi.org/10.1016/j.meegid.2017.10.013). Lastly, phylogenetic analysis was performed and correlated with clinical manifestation. In the explorative set, we observed 98.6% agreement between the line probe assay and the NGS-hsp65 database. In the validation set, 99.1% agreement between the NGS-WG and NGS-hsp65 databases was seen on the complex level. We identified a cluster of Mycobacterium marinum isolates not represented by the Tortoli et al. phylogeny. Phylogenetic analysis of M. avium complex isolates confirmed misclassification of M. timonense and M. bouchedurhonense and identified subclusters within M. avium although no correlation with clinical manifestation was observed. We performed routine NGS to identify NTM from MGIT enriched shotgun metagenomic data. Phylogenetic analyses identified subtypes of M. avium, but in our set of isolates no correlation with clinical manifestation was found. However, this NGS workflow paves a way for more personalized health care in the future.

Influenza A(H1N1)pdm09 But Not A(H3N2) Virus Infection Induces Durable Seroprotection: Results From the Ha Nam Cohort.

BACKGROUND: The extent to which influenza recurrence depends upon waning immunity from prior infection is undefined. We used antibody titers of Ha-Nam cohort participants to estimate protection curves and decay trajectories. METHODS: Households (270) participated in influenza-like-illness (ILI) surveillance and provided blood at intervals spanning laboratory-confirmed virus transmission. Sera were tested in hemagglutination inhibition assay. Infection was defined as influenza virus-positive ILI and/or seroconversion. Median protective titers were estimated using scaled-logistic regression to model pretransmission titer against infection status in that season, limiting analysis to households with infection(s). Titers were modelled against month since infection using mixed-effects linear regression to estimate decay and when titers fell below protection thresholds. RESULTS: From December 2008-2012, 295 and 314 participants were infected with H1N1pdm09-like and A/Perth/16/09-like (H3N2Pe09) viruses, respectively. The proportion protected rose more steeply with titer for H1N1pdm09 than for H3N2Pe09, and estimated 50% protection titers were 19.6 and 37.3, respectively. Postinfection titers started higher against H3N2Pe09 but decayed more steeply than against H1N1pdm09. Seroprotection was estimated to be sustained against H1N1pdm09 but to wane by 8-months for H3N2Pe09. CONCLUSIONS: Estimates indicate that infection induces durable seroprotection against H1N1pdm09 but not H3N2Pe09, which could in part account for the younger age of A(H1N1) versus A(H3N2) cases.

Endocarditis Caused by Nontypeable Streptococcus pneumoniae.

The Streptococcus pneumoniae capsule is regarded as indispensable in bacteremia. We report an infant with a ventricular septal defect and infective endocarditis caused by nontypeable S. pneumoniae. In-depth investigation confirmed a deficient capsule yet favored pneumococcal fitness for causing infective endocarditis, rather than a host immune disorder, as the cause of infective endocarditis in this case.

RNA Sequencing Elucidates Drug-Specific Mechanisms of Antibiotic Tolerance and Resistance in Mycobacterium abscessus.

Mycobacterium abscessus is an opportunistic pathogen notorious for its resistance to most classes of antibiotics and low cure rates. M. abscessus carries an array of mostly unexplored defense mechanisms. A deeper understanding of antibiotic resistance and tolerance mechanisms is pivotal in development of targeted therapeutic regimens. We provide the first description of all major transcriptional mechanisms of tolerance to all antibiotics recommended in current guidelines, using RNA sequencing-guided experiments. M. abscessus ATCC 19977 bacteria were subjected to subinhibitory concentrations of clarithromycin (CLR), amikacin (AMK), tigecycline (TIG), cefoxitin (FOX), and clofazimine (CFZ) for 4 and 24 h, followed by RNA sequencing. To confirm key mechanisms of tolerance suggested by transcriptomic responses, we performed time-kill kinetic analysis using bacteria after preexposure to CLR, AMK, or TIG for 24 h and constructed isogenic knockout and knockdown strains. To assess strain specificity, pan-genome analysis of 35 strains from all three subspecies was performed. Mycobacterium abscessus shows both drug-specific and common transcriptomic responses to antibiotic exposure. Ribosome-targeting antibiotics CLR, AMK, and TIG elicit a common response characterized by upregulation of ribosome structural genes, the WhiB7 regulon and transferases, accompanied by downregulation of respiration through NuoA-N. Exposure to any of these drugs decreases susceptibility to ribosome-targeting drugs from multiple classes. The cytochrome bd-type quinol oxidase contributes to CFZ tolerance in M. abscessus, and the sigma factor sigH but not antisigma factor MAB_3542c is involved in TIG resistance. The observed transcriptomic responses are not strain-specific, as all genes involved in tolerance, except erm(41), are found in all included strains.

The Effect of Different Types of Prostate Biopsy Techniques on Post-Biopsy Infectious Complications.

PURPOSE: The aim of our study was to compare infectious complication rates between different prostate biopsy techniques with various number of biopsy cores. MATERIALS AND METHODS: In this retrospective study, all patients from 2 hospitals who underwent prostate biopsy between 2012 and 2019 were identified. Cohorts with different types of prostate biopsies were compiled within these hospitals. Primary outcome measure was any registered infectious complication within 7 days post-biopsy. Secondary outcomes were infectious complications within 30 days, hospitalization and bacteremia. To compare the risk of infection following different prostate biopsy techniques, data was fitted into a logistic regression model adjusting for potential confounders. RESULTS: In total, 4,233 prostate biopsies in 3,707 patients were included. After systematic transrectal ultrasound-guided prostate biopsy (TRUSPB; 12±1.4 biopsy cores), 4.0% (2,607) of all patients had infectious complications within 7 days post-biopsy. Transperineal magnetic resonance imaging (MRI)-ultrasound fusion guided prostate biopsy (16±3.7 biopsy cores) was associated with significantly lower infection rates than systematic TRUSPB (adjusted OR: 0.29 [0.09-0.73] 95% confidence interval [CI]). Transrectal targeted MRI-ultrasound fusion guided prostate biopsy (3.1±0.8 biopsy cores) and transrectal targeted in-bore MRI guided prostate biopsy (2.8±0.8 biopsy cores) also showed fewer infectious complications than systematic TRUSPB (adjusted OR: 0.41 [0.12-1.12] 95% CI and 0.68 [0.37-1.20] 95% CI, respectively). CONCLUSIONS: Transperineal prostate biopsy, or transrectal prostate biopsy with reduced number of biopsy cores, could lower the risk of infectious complications.

The Benzimidazole SPR719 Shows Promising Concentration-Dependent Activity and Synergy against Nontuberculous Mycobacteria.

Nontuberculous mycobacterial pulmonary disease (NTM-PD) is emerging worldwide. Currently recommended multidrug treatment regimens yield poor outcomes, and new drugs and regimens are direly needed. SPR719, the active moiety of SPR720, is a new benzimidazole antibiotic with limited data on antimycobacterial activity. We determined MICs and MBCs against 138 clinical and reference strains of M. avium complex (MAC), M. kansasii, M. abscessus, M. xenopi, M. malmoense, and M. simiae and determined synergy with antimycobacterial drugs by checkerboard titrations. To study pharmacodynamics, we performed time-kill kinetics assays of SPR719 alone and in combinations against M. avium, M. kansasii, and M. abscessus and assessed synergy by response surface analysis according to Bliss independence. SPR719 showed potent activity against MAC (MIC90, 2 mg/liter) and M. kansasii (MIC90, 0.125 mg/liter) and modest activity against M. abscessus (MIC90, 8 mg/liter); its activity is bacteriostatic and concentration-dependent. We recorded a potential for combination therapy with ethambutol against M. kansasii and M. avium and synergy with clarithromycin against M. abscessus Ethambutol increased the SPR719 kill rate against M. kansasii but only prevented SPR719 resistance in M. avium SPR719 is active in vitro against NTM; its activity is strongest against M. kansasii, followed by MAC and M. abscessus SPR719 shows promise for combination therapy with ethambutol against MAC and M. kansasii and synergy with clarithromycin against M. abscessus The parent drug SPR720 could have a role especially in MAC pulmonary disease treatment. Further studies in dynamic models and trials are ongoing to advance clinical development.

An In Vitro Perspective on What Individual Antimicrobials Add to Mycobacterium avium Complex Therapies.

For Mycobacterium avium complex pulmonary disease (MAC-PD), current treatment regimens yield low cure rates. To obtain an evidence-based combination therapy, we assessed the in vitro activity of six drugs, namely, clarithromycin (CLR), rifampin (RIF), ethambutol (EMB), amikacin (AMK), clofazimine (CLO), and minocycline (MIN), alone and in combination, against Mycobacterium avium and studied the contributions of individual antibiotics to efficacy. The MICs of all antibiotics against M. avium ATCC 700898 were determined by broth microdilution. We performed kinetic time-kill assays of all single drugs and clinically relevant two-, three-, four-, and five-drug combinations against M. avium. Pharmacodynamic interactions of these combinations were assessed using area under the time-kill curve-derived effect size and Bliss independence. Adding a second drug yielded an average increase of the effect size (E) of 18.7% ± 32.9%, although antagonism was seen in some combinations. Adding a third drug showed a smaller increase in effect size (+12.2% ± 11.5%). The RIF-CLO-CLR (E of 102 log10 CFU/ml · day), RIF-AMK-CLR (E of 101 log10 CFU/ml · day), and AMK-MIN-EMB (E of 97.8 log10 CFU/ml · day) regimens proved more active than the recommended RIF-EMB-CLR regimen (E of 89.1 log10 CFU/ml · day). The addition of a fourth drug had little impact on effect size (+4.54% ± 3.08%). In vitro, several two- and three-drug regimens are as effective as the currently recommended regimen for MAC-PD. Adding a fourth drug to any regimen had little additional effect. In vitro, the most promising regimen would be RIF-AMK-macrolide or RIF-CLO-macrolide.

Thioridazine Is an Efflux Pump Inhibitor in Mycobacterium avium Complex but of Limited Clinical Relevance.

Treatment of Mycobacterium avium complex pulmonary disease (MAC-PD) is challenging partly due to high efflux pump expression. Thioridazine might block these efflux pumps. We explore the efficacy of thioridazine against M. avium isolates using MICs, time-kill combination assays, ex vivo macrophage infection assays, and efflux assays. Thioridazine is bactericidal against M. avium, inhibits intracellular growth at 2× MIC, and blocks ethidium bromide efflux. However, its toxicity and low plasma concentrations make it unlikely to add efficacy to MAC-PD therapy.

A Trial of Itraconazole or Amphotericin B for HIV-Associated Talaromycosis.

BACKGROUND: Talaromyces marneffei infection is a major cause of human immunodeficiency virus (HIV)-related death in South and Southeast Asia. Guidelines recommend initial treatment with amphotericin B deoxycholate, but this drug has substantial side effects, a high cost, and limited availability. Itraconazole is available in oral form, is associated with fewer unacceptable side effects than amphotericin, and is widely used in place of amphotericin; however, clinical trials comparing these two treatments are lacking. METHODS: In this open-label, noninferiority trial, we randomly assigned 440 HIV-infected adults who had talaromycosis, confirmed by either microscopy or culture, to receive either intravenous amphotericin B deoxycholate (amphotericin) (219 patients), at a dose of 0.7 to 1.0 mg per kilogram of body weight per day, or itraconazole capsules (221 patients), at a dose of 600 mg per day for 3 days, followed by 400 mg per day, for 11 days; thereafter, all the patients received maintenance therapy with itraconazole. The primary outcome was all-cause mortality at week 2. Secondary outcomes included all-cause mortality at week 24, the time to clinical resolution of talaromycosis, early fungicidal activity, relapse of talaromycosis, development of the immune reconstitution inflammatory syndrome (IRIS), and the side-effect profile. RESULTS: The risk of death at week 2 was 6.5% in the amphotericin group and 7.4% in the itraconazole group (absolute risk difference, 0.9 percentage points; 95% confidence interval [CI], -3.9 to 5.6; P<0.001 for noninferiority); however, the risk of death at week 24 was 11.3% in the amphotericin group and 21.0% in the itraconazole group (absolute risk difference, 9.7 percentage points; 95% CI, 2.8 to 16.6; P=0.006). Treatment with amphotericin was associated with significantly faster clinical resolution and fungal clearance and significantly lower rates of relapse and IRIS than itraconazole. The patients who received amphotericin had significantly higher rates of infusion-related reactions, renal failure, hypokalemia, hypomagnesemia, and anemia than patients in the itraconazole group. CONCLUSIONS: Amphotericin was superior to itraconazole as initial treatment for talaromycosis with respect to 6-month mortality, clinical response, and fungicidal activity. (Funded by the Medical Research Council and others; IVAP Current Controlled Trials number, ISRCTN59144167 .).

Efficacy and safety of selective decontamination of the digestive tract (SDD) to prevent recurrent hepatic cyst infections in polycystic liver disease: a retrospective case series.

BACKGROUND: Hepatic cyst infection is a complication of polycystic liver disease (PLD) that causes substantial morbidity. Repetitive infection is frequent and is increasingly difficult to treat. As translocated gut bacteria are considered the cause, we hypothesize that selective decontamination of the digestive tract (SDD) reduces recurrence of hepatic cyst infection. METHODS: We performed a retrospective, observational study in two referral centres. All patients with PLD treated with SDD for hepatic cyst infection were included. Efficacy was determined by calculating the infection incidence (hepatic cyst infections per month) before and during SDD therapy. Adverse events were scored according to the Common Terminology Criteria for Adverse Events (CTCAE). RESULTS: We identified eight patients who received SDD (88% female, 88% polycystic kidney disease). The median age was 65 years (IQR: 51-74 years). SDD lowered the median incidence from 0.09 episodes per month (IQR: 0.06-0.25 episodes per month) to 0.01 episodes per month (IQR: 0.00-0.05 episodes per month) (P = 0.12). Discontinuation of SDD led to rapid recurrence of cyst infection (71% within 6 weeks). SDD consisted of polymyxins with/without aminoglycosides. The median SDD treatment duration was 20 months (range: 3-89 months). Six patients (75%) developed adverse events [CTCAE Grade 1 (gastrointestinal: n = 3) or Grade 3 (ototoxicity: n = 1; fungal infection: n = 1)], mostly attributable to aminoglycosides; one patient developed polymyxin E resistance. CONCLUSIONS: SDD prophylaxis provides a novel strategy for limiting recurrent hepatic cyst infection in PLD patients. However, adverse events are frequent and curtail its use. As most were attributable to aminoglycosides, polymyxin E is considered the preferred therapy.

Inhaled tigecycline is effective against Mycobacterium abscessus in vitro and in vivo.

BACKGROUND: Mycobacterium abscessus causes chronic pulmonary infections. Owing to its resistance to most classes of antibiotics, treatment is complex and cure rates are only 45%. Tigecycline is active against M. abscessus, but severe toxicity and the need for IV administration limit its use. OBJECTIVES: To assess the potential of inhaled tigecycline as a treatment for M. abscessus pulmonary disease, by measuring its efficacy in a mouse model of chronic M. abscessus pulmonary disease, establishing the intracellular activity of tigecycline against M. abscessus in human macrophages and measuring the activity of tigecycline in the sputum of cystic fibrosis patients. METHODS: We infected GM-CSF knockout mice with M. abscessus by intrapulmonary aerosol. Infected mice were treated with tigecycline in 0.25, 1.25 and 2.5 mg doses, by inhalation, or untreated, for 28 days. Tigecycline was added to human peripheral blood-derived macrophages infected with M. abscessus to assess its intracellular activity. We performed a time-kill kinetics experiment of tigecycline against M. abscessus with and without sputum of cystic fibrosis patients. RESULTS: Inhaled tigecycline proved highly effective against M. abscessus in GM-CSF knockout mice. The effect was dose dependent. Tigecycline showed potent activity against M. abscessus in macrophages and retained most of its activity in the presence of sputum of cystic fibrosis patients. CONCLUSIONS: Inhaled tigecycline may represent a viable treatment option for M. abscessus pulmonary disease, where treatment outcomes are currently very poor. A stable and safe formulation is required to proceed to further pharmacodynamic studies and ultimately clinical trials.

Is there a role for tedizolid in the treatment of non-tuberculous mycobacterial disease?

BACKGROUND: Pulmonary infections caused by non-tuberculous mycobacteria (NTM) are hard to treat and have low cure rates despite intensive multidrug therapy. OBJECTIVES: To assess the feasibility of tedizolid, a new oxazolidinone, for the treatment of Mycobacterium avium and Mycobacterium abscessus. METHODS: We determined MICs of tedizolid for 113 isolates of NTM. Synergy with key antimycobacterial drugs was assessed using the chequerboard method and calculation of the FIC index (FICI). We performed time-kill kinetics assays of tedizolid alone and combined with amikacin for M. abscessus and with ethambutol for M. avium. Human macrophages were infected with M. abscessus and M. avium and subsequently treated with tedizolid; intracellular and extracellular cfu were quantified over time. RESULTS: NTM isolates generally had a lower MIC of tedizolid than of linezolid. FICIs were lowest between tedizolid and amikacin for M. abscessus (FICI = 0.75) and between tedizolid and ethambutol for M. avium (FICI = 0.72). Clarithromycin and tedizolid showed initial synergy, which was abrogated by erm(41)-induced macrolide resistance (FICI = 0.53). Tedizolid had a weak bacteriostatic effect on M. abscessus and combination with amikacin slightly prolonged its effect. Tedizolid had concentration-dependent activity against M. avium and its efficacy was enhanced by ethambutol. Both combinations had a concentration-dependent synergistic effect. Tedizolid could inhibit the intracellular bacterial population of both M. avium and M. abscessus. CONCLUSIONS: Tedizolid should be further investigated in pharmacodynamic studies and clinical trials for M. avium complex pulmonary disease. It is less active against M. abscessus, but still promising.

Prostate biopsy techniques and pre-biopsy prophylactic measures: variation in current practice patterns in the Netherlands.

BACKGROUND: The clinical landscape of prostate biopsy (PB) is evolving with changes in procedures and techniques. Moreover, antibiotic resistance is increasing and influences the efficacy of pre-biopsy prophylactic regimens. Therefore, increasing antibiotic resistance may impact on clinical care, which probably results in differences between hospitals. The objective of our study is to determine the (variability in) current practices of PB in the Netherlands and to gain insight into Dutch urologists' perceptions of fluoroquinolone resistance and biopsy related infections. METHODS: An online questionnaire was prepared using SurveyMonkey® platform and distributed to all 420 members of the Dutch Association of Urology, who work in 81 Dutch hospitals. Information about PB techniques and periprocedural antimicrobial prophylaxis was collected. Urologists' perceptions regarding pre-biopsy antibiotic prophylaxis in an era of antibiotic resistance was assessed. Descriptive statistical analysis was performed. RESULTS: One hundred sixty-one responses (38.3%) were analyzed representing 65 (80.3%) of all Dutch hospitals performing PB. Transrectal ultrasound guided prostate biopsy (TRUSPB) was performed in 64 (98.5%) hospitals. 43.1% of the hospitals (also) used other image-guided biopsy techniques. Twenty-three different empirical prophylactic regimens were reported among the hospitals. Ciprofloxacin was most commonly prescribed (84.4%). The duration ranged from one pre-biopsy dose (59.4%) to 5 days extended prophylaxis. 25.2% of the urologists experienced ciprofloxacin resistance as a current problem in the prevention of biopsy related infections and 73.6% as a future problem. CONCLUSIONS: There is a wide variation in practice patterns among Dutch urologists. TRUSPB is the most commonly used biopsy technique, but other image-guided biopsy techniques are increasingly used. Antimicrobial prophylaxis is not standardized and prolonged prophylaxis is common. The wide variation in practice patterns and lack of standardization underlines the need for evidence-based recommendations to guide urologists in choosing appropriate antimicrobial prophylaxis for PB in the context of increasing antibiotic resistance.

Every medicine is medicine; exploring inappropriate antibiotic use at the community level in rural Ghana.

BACKGROUND: Inappropriate antibiotic use is an important driver of antibiotic resistance. This study sought to explore inappropriate antibiotic use and confusing antibiotics with other medicines in Ghana using ethnomethodology research approach. METHODS: This was an explorative study involving 15 in-depth interviews among health professionals and private dispensers and eight focus group discussions among 55 community members. Qualitative data were coded using Nvivo 12, thematically analysed and presented as narratives with quotes to support the findings. RESULTS: Self-medication was common and antibiotics were used to treat specific diseases but respondents were not aware these were 'antibiotics'. Various antibiotics were used for indications that in principle do not require systemic antibiotics, like stomach ache and sores on the body. Antibiotics, in particular tetracycline and metronidazole, were poured into "akpeteshie" (local gin) to treat hernia and perceived stomach sores (stomach ulcer). These practices were copied/learnt from various sources like over-the-counter medicine sellers, family, friends, radio/television, drug peddlers, pharmacies and doctors. Medicines in capsules were referred to as 'topaye' or 'abombelt' in Twi (local dialect) and perceived to treat pain associated with diseases. Antibiotics in capsules were described with colours which appeared confusing as some capsules with different drugs in them have similar colours. CONCLUSION: Inappropriate antibiotic use were influenced by general lack of knowledge on antibiotics and identification of antibiotics by colours of capsules which leads to confusion and could lead to inappropriate antibiotic use. There is the need for public health education on appropriate antibiotic use and standardization of appearance of antibiotics and other drugs to optimize use.

Auranofin Activity Exposes Thioredoxin Reductase as a Viable Drug Target in Mycobacterium abscessus.

Nontuberculous mycobacteria (NTM) are highly drug-resistant, opportunistic pathogens that can cause pulmonary disease. The outcomes of the currently recommended treatment regimens are poor, especially for Mycobacterium abscessus New or repurposed drugs are direly needed. Auranofin, a gold-based antirheumatic agent, was investigated for Mycobacterium tuberculosis Here, we test auranofin against NTM in vitro and ex vivo We tested the susceptibility of 63 NTM isolates to auranofin using broth microdilution. Next, we assessed synergy between auranofin and antimycobacterial drugs using the checkerboard method and calculated the fractional inhibition concentration index (FICI). Using time-kill kinetics assays (TK), we assessed pharmacodynamics of auranofin alone and in combination with drug combinations showing the lowest FICIs for M. abscessus CIP 104536. A response surface analysis was used to assess synergistic interactions over time in TKs. Primary isolated macrophages were infected with M. abscessus and treated with auranofin. Finally, using KEGG Orthology, we looked for orthologues to auranofins drug target in M. tuberculosisM. abscessus had the lowest auranofin MIC50 (2 µg/ml) among the tested NTM. The lowest average FICIs were observed between auranofin and amikacin (0.45) and linezolid (0.50). Auranofin exhibited concentration-dependent killing of M. abscessus, with >1-log killing at concentrations of >2× MIC. Only amikacin was synergistic with auranofin according to Bliss independence. Auranofin could not lower the intracellular bacterial load in macrophages. Auranofin itself may not be feasible for M. abscessus treatment, but these data point toward a promising, unutilized drug target.