A naturally inspired antibiotic to target multidrug-resistant pathogens.

Gram-negative bacteria are responsible for an increasing number of deaths caused by antibiotic-resistant infections1,2. The bacterial natural product colistin is considered the last line of defence against a number of Gram-negative pathogens. The recent global spread of the plasmid-borne mobilized colistin-resistance gene mcr-1 (phosphoethanolamine transferase) threatens the usefulness of colistin3. Bacteria-derived antibiotics often appear in nature as collections of similar structures that are encoded by evolutionarily related biosynthetic gene clusters. This structural diversity is, at least in part, expected to be a response to the development of natural resistance, which often mechanistically mimics clinical resistance. Here we propose that a solution to mcr-1-mediated resistance might have evolved among naturally occurring colistin congeners. Bioinformatic analysis of sequenced bacterial genomes identified a biosynthetic gene cluster that was predicted to encode a structurally divergent colistin congener. Chemical synthesis of this structure produced macolacin, which is active against Gram-negative pathogens expressing mcr-1 and intrinsically resistant pathogens with chromosomally encoded phosphoethanolamine transferase genes. These Gram-negative bacteria include extensively drug-resistant Acinetobacter baumannii and intrinsically colistin-resistant Neisseria gonorrhoeae, which, owing to a lack of effective treatment options, are considered among the highest level threat pathogens4. In a mouse neutropenic infection model, a biphenyl analogue of macolacin proved to be effective against extensively drug-resistant A. baumannii with colistin-resistance, thus providing a naturally inspired and easily produced therapeutic lead for overcoming colistin-resistant pathogens.

Gut microbiome in association with chemotherapy-induced toxicities among patients with breast cancer.

BACKGROUND: Little research has focused on the relationship between gut microbiome and chemotherapy-induced toxicity. METHODS: This prospective study involves 301 patients with breast cancer who had prechemotherapy stool samples collected. Gut microbiome was sequenced by shotgun metagenomics; associations with chemotherapy-induced toxicities during first-line treatment by gut microbial diversity, composition, and metabolic pathways with severe (i.e., grade ≥3) hematological and gastrointestinal toxicities were evaluated via multivariable logistic regression. RESULTS: High prechemotherapy α-diversity was associated with a significantly reduced risk of both severe hematological toxicity (odds ratio [OR] = 0.94; 95% CI, 0.89-0.99; p = .048) and neutropenia (OR = 0.94; 95% CI, 0.89-0.99; p = .016). A high abundance of phylum Synergistota, class Synergistia, and order Synergistales were significantly associated with a reduced risk of severe neutropenia; conversely, enrichment of phylum Firmicutes C, class Negativicutes, phylum Firmicutes I, and class Bacilli A, order Paenibacillales were significantly associated with an increased risk of severe neutropenia (p range: 0.012-2.32 × 10-3; false discovery rate <0.1). Significant positive associations were also observed between severe nausea/vomiting and high Chao1 indexes, ß-diversity (p < .05), 20 species belonging to the family Lachnospiraceae, Oscillospiraceae, and Ruminococcaceae (p value range: 6.14 × 10-3 to 1.33 × 10-5; false discovery rate <0.1), and three metabolic pathways involved in reductive tricarboxylic acid cycle I and cycle II, and an incomplete reductive tricarboxylic acid cycle (p < .01). Conversely, a high abundance of species Odoribacter laneus and the pathway related to the L-proline biosynthesis II were inversely associated with severe nausea/vomiting. CONCLUSIONS: Our study suggests that gut microbiota may be a potential preventive target to reduce chemotherapy-induced toxicity.

Clinical significance and outcomes of Clostridium tertium bacteremia: analysis of 62 cases in neutropenic and non-neutropenic patients.

The clinical significance of Clostridium tertium bacteremia is still uncertain. We evaluated the incidence, clinical characteristics, and outcomes of C. tertium bacteremia and identified differences between neutropenia and non-neutropenia. All adult patients with C. tertium bacteremia in a 2700-bed tertiary center between January 2004 and November 2021 were retrospectively enrolled. The first episode of C. tertium bacteremia in each patient was included in the analysis. Among 601 patients with Clostridium species bacteremia, 62 (10%) had C. tertium bacteremia, and of these 62 patients, 39 (63%) had had recent chemotherapy, and 31 (50%) had neutropenia or hematologic malignancy. C. tertium bacteremia originated frequently from a gastrointestinal tract infection such as enterocolitis (34%), primary bacteremia (29%), and secondary peritonitis (18%), and 34% of patients had polymicrobial bacteremia. Hematologic malignancy, prior antibiotic treatment, neutropenic enterocolitis, and primary bacteremia were significantly associated with C. tertium bacteremia in neutropenic patients, whereas solid tumor, hepatobiliary disease, secondary peritonitis, polymicrobial bacteremia, and a higher frequency of eradicable infection foci were significantly associated with C. tertium bacteremia in non-neutropenic patients. There was 15% 30-day mortality. APACHE II score (adjusted odds ratio [aOR], 1.5; 95% confidence interval [CI], 1.1-2.1) and secondary peritonitis (aOR, 25.9; 95% CI, 3.0-224.7) were independent risk factors for 30-day mortality. The prevalence of C. tertium bacteremia is low, and the characteristics of C. tertium bacteremia are significantly different between neutropenic and non-neutropenic patients. Appropriate investigation for gastrointestinal mucosal injury should be performed to improve treatment outcomes in this form of bacteremia.

Clinical and microbiological profiles in post-chemotherapy neutropenic fever in hematological malignancy: exploration of clinical phenotype patterns by two-step cluster analysis.

BACKGROUND: Epidemiology of infectious diseases causing febrile illness varies geographically with human attributes. Periodic institutional surveillance of clinical and microbiological profiles in adding data to updating trends, modulating pharmatherapeutics, signifying possible excessive treatments and risk of drug resistance in post-chemotherapy neutropenic fever (NF) in hematological malignancy (HM) is limited. We aimed to review institutional clinical and microbiological data and explore clinical phenotype pattern groups among data. METHODS: Available data from 372 NF episodes were included. Demographics, types of malignancies, laboratory data, antimicrobial treatments and febrile-related outcome data such as predominant pathogens and microbiological diagnosed infections (MDIs) were collected. Descriptive statistics, two-step cluster analysis and non-parametric tests were employed. RESULTS: The occurrences of microbiological diagnosed bacterial infections (MDBIs; 20.2%) and microbiological diagnosed fungal infections (MDFIs; 19.9%) were almost equal. Gram-negative pathogens (11.8%) were comparable with gram-positive pathogens (9.9%), with gram-negative being slightly predominant. Death rate was 7.5%. Two-step cluster analysis yielded four distinct clinical phenotype pattern (cluster) groups: cluster 1 'lymphomas without MDIs', cluster 2 'acute leukemias MDBIs', cluster 3 'acute leukemias MDFIs' and cluster 4 'acute leukemias without MDIs'. Considerable NF events with antibiotic prophylaxis being not identified as MDI might have cases in low-risk with non-infectious reasons causing febrile reactions that might possibly not require prophylaxis. CONCLUSIONS: Regular institutional surveillance with active parameter assessments to signify risk levels in the post-chemotherapy stage, even prior to the onset of fever, might be an evidence-based strategy in the management of NF in HM.

Fluoroquinolone prophylaxis in patients with neutropenia at high risk of serious infections: Exploring pros and cons.

BACKGROUND: The use of fluoroquinolones to prevent infections in neutropenic patients with cancer or undergoing hematopoietic stem cell transplantation (HSCT) is a controversial issue, with international guidelines providing conflicting recommendations. Although potential benefits are clear, concerns revolve around efficacy, potential harms, and antimicrobial resistance (AMR) implications. DISCUSSION: Fluoroquinolone prophylaxis reduces neutropenic fever (NF) bloodstream infections and other serious bacterial infections, based on evidence from systematic reviews, randomized controlled trials, and observational studies in adults and children. Fluoroquinolone prophylaxis may also reduce infection-related morbidity and healthcare costs; however, evidence is conflicting. Adverse effects of fluoroquinolones are well recognized in the general population; however, studies in the cancer cohort where it is used for a defined period of neutropenia have not reflected this. The largest concern for routine use of fluoroquinolone prophylaxis remains AMR, as many, but not all, observational studies have found that fluoroquinolone prophylaxis might increase the risk of AMR, and some studies have suggested negative impacts on patient outcomes as a result. CONCLUSIONS: The debate surrounding fluoroquinolone prophylaxis calls for individualized risk assessment based on patient characteristics and local AMR patterns, and prophylaxis should be restricted to patients at the highest risk of serious infection during the highest risk periods to ensure that the risk-benefit analysis is in favor of individual and community benefit. More research is needed to address important unanswered questions about fluoroquinolone prophylaxis in neutropenic patients with cancer or receiving HSCT.

Platelets are critical for survival and tissue integrity during murine pulmonary Aspergillus fumigatus infection.

Beyond their canonical roles in hemostasis and thrombosis, platelets function in the innate immune response by interacting directly with pathogens and by regulating the recruitment and activation of immune effector cells. Thrombocytopenia often coincides with neutropenia in patients with hematologic malignancies and in allogeneic hematopoietic cell transplant recipients, patient groups at high risk for invasive fungal infections. While neutropenia is well established as a major clinical risk factor for invasive fungal infections, the role of platelets in host defense against human fungal pathogens remains understudied. Here, we examined the role of platelets in murine Aspergillus fumigatus infection using two complementary approaches to induce thrombocytopenia without concurrent neutropenia. Thrombocytopenic mice were highly susceptible to A. fumigatus challenge and rapidly succumbed to infection. Although platelets regulated early conidial phagocytosis by neutrophils in a spleen tyrosine kinase (Syk)-dependent manner, platelet-regulated conidial phagocytosis was dispensable for host survival. Instead, our data indicated that platelets primarily function to maintain hemostasis and lung integrity in response to exposed fungal antigens, since thrombocytopenic mice exhibited severe hemorrhage into the airways in response to fungal challenge in the absence of overt angioinvasion. Challenge with swollen, heat-killed, conidia was lethal in thrombocytopenic hosts and could be reversed by platelet transfusion, consistent with the model that fungus-induced inflammation in platelet-depleted mice was sufficient to induce lethal hemorrhage. These data provide new insights into the role of platelets in the anti-Aspergillus host response and expand their role to host defense against filamentous molds.

Characteristics of gram-negative bacteremia during febrile neutropenia among allogeneic hematopoietic stem cell transplant recipients on levofloxacin prophylaxis.

The aim of this study is to clarify the characteristics of gram-negative bacteremia (GNB), including extended-spectrum ß-lactamase (ESBL)-producing pathogens, among allogeneic hematopoietic stem cell transplant (allo-HSCT) recipients on levofloxacin (LVFX) prophylaxis. A retrospective analysis on GNB at the first episode of febrile neutropenia (FN) was conducted among allo-HSCT recipients (age ≥ 20 years) on 500 mg/day of oral LVFX prophylaxis. Epidemiological and microbiological features of GNB were investigated and compared between the inappropriate and appropriate empiric therapy groups. In total, FN occurred in 414 allo-HSCT cases, and bacteremia at the first episode of FN occurred in 169 cases. Overall, 29 GNB cases were documented, and the causative organisms identified were Escherichia coli in 21 cases (including 10 ESBLs), Klebsiella pneumoniae in 2, Pseudomonas aeruginosa in 2, and other in 4. The crude 30-day mortality rate was not significantly different among cases of GNB (6.9%), gram-positive bacteremia (GPB) (7.1%), or non-bacteremia (5.4%; P = 0.78). Cefepime (CFPM) was administered in all cases in the inappropriate empiric therapy group, and all causative organisms were ESBL-producing E. coli (ESBL-EC). All patients in the inappropriate empiric therapy group had a low Pitt bacteremia score (≤ 2). Thirty-day mortality did not differ significantly between the inappropriate and appropriate empiric therapy groups (1/10 vs. 1/15, P = 0.61). In conclusion, GNB was not a significant cause of death. In LVFX breakthrough ESBL-EC bacteremia among allo-HSCT recipients, the administration of CFPM as empiric therapy did not lead to significantly poor prognosis. Empiric CFPM administration might be an acceptable strategy.

Cefmetazole as an Alternative to Carbapenems Against Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Infections Based on In Vitro and In Vivo Pharmacokinetics/Pharmacodynamics Experiments.

PURPOSE: Cefmetazole (CMZ) has received attention as a pharmaceutical intervention for extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) infections. This study aimed to investigate the pharmacokinetics/pharmacodynamics (PK/PD) characteristics of CMZ against ESBL-EC. METHODS: The susceptibility and time-killing activity of CMZ against clinically isolated ESBL-EC (EC9 and EC19) were determined in vitro. The optimal PK/PD index and its target value were calculated based on the results of a PK study in healthy mice and PD study in neutropenic murine thigh infection model mice. RESULTS: The minimum inhibitory concentrations (MICs) of CMZ against EC9 and EC19 were 2.0 and 1.0 µg/mL, respectively. Time-kill studies showed that colony-forming units decreased in a time-dependent manner at CMZ concentrations in the range of 4-64 × MIC. In in vivo PK/PD studies, the antibacterial effect of CMZ showed the better correlation with the time that the free drug concentration remaining above the MIC (fT>MIC), with the target values for a static effect and 1 log10 kill reduction calculated as 57.6% and 69.6%, respectively. CONCLUSION: CMZ possesses time-dependent bactericidal activities against ESBL-EC and is required to achieve "fT>MIC" ≥ 69.6% for the treatment of ESBL-EC infections.

Comparison of myelosuppression using the D-index between children and adolescents/young adults with acute lymphoblastic leukemia during induction chemotherapy.

BACKGROUND: Adolescents and young adults (AYAs) with acute lymphoblastic leukemia (ALL) are more likely to have chemotherapy-related complications than children. In addition, several reports have shown that infections account for most of the therapy-related mortality during cancer treatment in AYAs. Thus, we hypothesized that chemotherapy-induced myelosuppression is more severe in AYAs than in children, and the state of neutropenia was compared between children and AYAs using the D-index, a numerical value calculated from the duration and depth of neutropenia. PROCEDURE: This study retrospectively analyzed 95 patients newly diagnosed with ALL at our institution between 2007 and 2019. Of these, 81 were children (<15 years old) and 14 were AYAs (≥15 years old). The D-index and duration of neutropenia during induction chemotherapy for ALL were compared between children and AYAs. RESULTS: The median D-index of children was significantly higher than that of AYAs (8187 vs 6446, respectively, P = .017). Moreover, the median duration of neutropenia was also significantly longer in children than in AYAs (24.0 days vs 11.5 days, respectively, P = .007). CONCLUSION: Contrary to our expectations, myelosuppressive toxicity during induction chemotherapy for ALL was more severe in children than in AYAs.

The prevalence of serious bacterial infections in neutropenic immunocompetent febrile children.

CONTEXT: Febrile neutropenic immunocompromised children are at a high risk of Serious Bacterial Infections (SBI). OBJECTIVE: This systematic review and meta-analysis report the prevalence of SBI in healthy children with febrile neutropenia. DATA SOURCE: PubMed, EMBASE, and Web of Science from their inception to August 2020. STUDY SELECTION: Patients with an Absolute Neutrophil Count (ANC) <1000 cells/mm3 up to 18 years of age presenting to the ED with a chief complaint of fever (temperature > 38°C) and who had a workup for SBI as defined by each study. DATA ABSTRACTION: Data from individual studies was abstracted by a subset of the authors and checked independently by the senior author. Any discrepancies were adjudicated by the joint agreement of all the authors. We calculated the prevalence of SBI by using the number of SBI's as the numerator and the total number of febrile events in patients as the denominator. Bias in our studies was quantified by the Newcastle Ottawa Scale. RESULTS: We identified 2066 citations of which five studies (1693 patients) our inclusion criteria. None of our reviewed studies consistently tested every included patient for SBI. Spectrum bias in every study resulted in a wide range of the SBI prevalence of 1.9% (<0.01% - 11%) similar to non-neutropenic children. LIMITATIONS: All of our studies were retrospective and many did not consistently screen all subjects for SBI. CONCLUSION: If the clinical suspicion is low, the risk for SBI is similar between febrile healthy neutropenic and non-neutropenic children.

Clinical Predictive Model of Multidrug Resistance in Neutropenic Cancer Patients with Bloodstream Infection Due to Pseudomonas aeruginosa.

We aimed to assess the rate and predictive factors of bloodstream infection (BSI) due to multidrug-resistant (MDR) Pseudomonas aeruginosa in neutropenic cancer patients. We performed a multicenter, retrospective cohort study including oncohematological neutropenic patients with BSI due to P. aeruginosa conducted across 34 centers in 12 countries from January 2006 to May 2018. A mixed logistic regression model was used to estimate a model to predict the multidrug resistance of the causative pathogens. Of a total of 1,217 episodes of BSI due to P. aeruginosa, 309 episodes (25.4%) were caused by MDR strains. The rate of multidrug resistance increased significantly over the study period (P = 0.033). Predictors of MDR P. aeruginosa BSI were prior therapy with piperacillin-tazobactam (odds ratio [OR], 3.48; 95% confidence interval [CI], 2.29 to 5.30), prior antipseudomonal carbapenem use (OR, 2.53; 95% CI, 1.65 to 3.87), fluoroquinolone prophylaxis (OR, 2.99; 95% CI, 1.92 to 4.64), underlying hematological disease (OR, 2.09; 95% CI, 1.26 to 3.44), and the presence of a urinary catheter (OR, 2.54; 95% CI, 1.65 to 3.91), whereas older age (OR, 0.98; 95% CI, 0.97 to 0.99) was found to be protective. Our prediction model achieves good discrimination and calibration, thereby identifying neutropenic patients at higher risk of BSI due to MDR P. aeruginosa The application of this model using a web-based calculator may be a simple strategy to identify high-risk patients who may benefit from the early administration of broad-spectrum antibiotic coverage against MDR strains according to the local susceptibility patterns, thus avoiding the use of broad-spectrum antibiotics in patients at a low risk of resistance development.

Necrotizing fasciitis in haematological patients: a different scenario.

To describe and compare the characteristics of necrotizing fasciitis (NF) in patients with and without haematological malignancy. All adult patients diagnosed with NF and treated at our hospital were included (January 2010-March 2019). Diagnosis was based on intraoperative findings or consistent clinical/radiological characteristics, and patients were classified as group A (with haematological malignancy) or group B (without haematological malignancy). Student's t (quantitative), Fisher's exact (qualitative), and Kaplan-Meyer tests were used for the statistical analysis. The study included 29 patients: 8 in group A and 21 in group B. All haematological patients had severe neutropenia (0.2 [0.02-0.5] ×109 cells/L; p < 0.001) and positive blood cultures (100% vs. 61.9%; p = 0.04) at diagnosis. Gram-negative bacilli NF was more common in group A (87.5% vs. 9.5%; p = 0.001), predominantly due to Escherichia coli (50% vs. 9.5%; p = 0.056). Surgical treatment was less common in haematological patients (5 [62.5%] vs. 21 [100%]; p = 0.015). Overall, 9 (31%) patients died: 4 (50%) in group A and 5 (23.8%) in group B (p = 0.17). The univariate analysis showed that mortality tended to be higher (OR 3.2; 95%CI 0.57-17.7; p = 0.17) and to occur earlier (2.2 ± 2.6 vs. 14.2 ± 19.9 days; p = 0.13) in haematological patients. The LRINEC index > 6 did not predict mortality in either group. In our study, NF in patients with haematological malignancies was mainly due to Gram-negative bacilli, associated to high and early mortality rates. In our experience, the LRINEC scale was not useful for predicting mortality.

Comparison of the etiologic, microbiologic, clinical and outcome characteristics of febrile vs. non-febrile neutropenia in hospitalized immunocompetent children.

We compared the etiologic, microbiologic, clinical, and outcome picture among febrile and non-febrile immunocompetent children hospitalized during 2013-2015 with acute neutropenia (absolute neutrophil count < 1.5 × 109/L). Serious bacterial infections (SBI) were defined as culture-positive blood, urine, cerebrospinal fluid, articular fluid or stool infections, pneumonia, brucellosis, and rickettsiosis. Overall, 664 children < 18 years of age were enrolled; 407 (62.2%) had fever > 38.0 °C and 247 (37.8%) were non-febrile at admission. There were 425 (64.0%), 125 (18.8%), 48 (7.2%), and 66 (9.9%) patients aged 0-24 months, 2-6, 7-12, and > 12 years, respectively. No differences were recorded in the distribution of febrile vs. non-febrile patients among the age groups nor among the 3 neutropenia severity groups (< 0.5, 0.5-1.0 and 1.0-1.5 × 109/L). SBI infections were diagnosed in 98 (14.8%) patients, with higher rates among febrile patients vs. non-febrile patients (16.8% vs. 11.5%, P = 0.06). Brucellosis and rickettsiosis were diagnosed in 15.4% and 23.1% tests performed, respectively. 295/688 (42.9%) virologic examinations returned positive. Among patients < 24 months, more febrile ones had viral infectious compared with afebrile patients (P = 0.025). Acute leukemia was diagnosed in 6 patients. Neutropenia resolved in 163/323 (50.5%) patients during a 1-month follow-up. No differences were recorded in neutropenia resolution between febrile and non-febrile children among all 3 severity groups. Severe neutropenia was rare and occurred mainly in very young patients. SBIs were more common among febrile patients compared with non-febrile patients, but there was no association between severity of neutropenia or its resolution and the presence or absence of fever at diagnosis.

Utility of anaerobic bottles for the diagnosis of bloodstream infections.

BACKGROUND: Obligate anaerobes usually account for less than 10% of bacteria recovered from blood cultures (BC). The relevance of routine use of the anaerobic bottle is under debate. The aim of this study was to evaluate the utility of anaerobic bottles for the diagnosis of bloodstream infections (BSI). METHODS: We conducted a 6-month, retrospective, monocentric study in a tertiary hospital. All positive BC were grouped into a single episode of bacteremia when drawn within 7 consecutive days. Bacteremia were classified into contaminants and BSI. Charts of patients with BSI due to obligate anaerobes were studied. RESULTS: A total of 19,739 blood cultures were collected, 2341 of which (11.9%) were positive. Anaerobic bottles were positive in 1528 (65.3%) of all positive BC but were positive alone (aerobic bottles negative) in 369 (15.8%). Overall 1081 episodes of bacteremia were identified, of which 209 (19.3%) had positive anaerobic bottles alone. The majority 126/209 (60.3%) were contaminants and 83 (39.7%) were BSI. BSI due to facultative anaerobes, obligate aerobes and obligate anaerobes were identified in 67 (80.7%), 3 (3.6%) and 13 (15.7%) of these 83 episodes, respectively. BSI due to obligate anaerobic bacteria were reported in 9 patients with gastro-intestinal disease, in 3 with febrile neutropenia and in 1 burned patient. CONCLUSIONS: Anaerobic bottles contributed to the diagnosis of a significant number of episodes of bacteremia. Isolated bacteria were mostly contaminants and non-obligate anaerobic pathogens. Rare BSI due to obligate anaerobes were reported mainly in patients with gastro-intestinal disorders and during febrile neutropenia.

Successful treatment of fulminant Clostridioides difficile infection with emergent fecal microbiota transplantation in a patient with acute myeloid leukemia and prolonged, severe neutropenia.

We present a patient with acute myeloid leukemia and prolonged, severe neutropenia who developed fulminant Clostridioides difficile infection refractory to medical therapy and was high-risk for surgical intervention. He was treated with fecal microbiota transplantation (FMT) for life-saving cure. The patient had subsequent clinical improvement, however, developed multidrug-resistant Pseudomonas aeruginosa bacteremia 2 days post-procedure. We describe subsequent investigation of this event that found this bacteremia was not related to the donor stool administered during FMT. This case adds to the literature that FMT could be considered in heavily immunocompromised patients with fulminant Clostridioides difficile infection where maximal medical therapy has been ineffective and surgery may carry an excessively high mortality risk.

Clinical features and outcome of hepatosplenic fungal infections in children with haematological malignancies.

Hepatosplenic fungal infection (HSFI) is a severe invasive fungal infection observed during neutrophil recovery in patients with acute leukaemia treated with intensive chemotherapy. Retrospective analysis including all paediatric haematological malignancies patients with HSC treated in Children Cancer Hospital Egypt (2013-2018). Twenty-five patients with acute leukaemia developed HSFI (19 patients diagnosed as hepatosplenic candidiasis). Most of the cases (92%) occurred during the induction phase. Organs affected were as follows: liver in 18 patients, renal in 13 patients, spleen in 12 patients, skin in four patients and retina in one patient. Five (20%) patients had proven HSC, 14 (56%) probable and six (24%) possible HSFI. Ten patients had a PET-CT for response assessment. Candida tropicalis was the most common isolated spp. from blood/tissue culture. Six (24%) patients developed HSFI on top of antifungal prophylaxis. Steroids were given in 12 (52%) patients with HSFI as immune reconstitution syndrome (IRS). Caspofungin was the first line of treatment in 14 (56%) patients, liposomal amphotericin B in six (24%) patients and azoles in five (20%) patients. HSFI was associated with delayed of intensification phase of chemotherapy (median 42 days). The success rate was reported in 24 patients with complete response (68%) and partial response in (28%) patients, while failure (death) seen in 1(4%) patient. HSC is still a major challenge in paediatric leukaemias patients with impact on treatment delay and survival outcome. PET scan, non-culture diagnostics and steroid role evidence in IRS are growing. Antifungal stewardship for screening, early detection for high-risk patients and better response assessment is challenging.

Synergistic Effect of a Pleuromutilin Derivative with Tetracycline against Streptococcus suis In Vitro and in the Neutropenic Thigh Infection Model.

Tetracycline (TET) has been widely used in the treatment of Streptococcus suis (S. suis) infection. However, it was found that the efficacy of many antibiotics in S. suis decreased significantly, especially tetracycline. In this study, GML-12 (a novel pleuromutilin derivative) was used in combination with TET against 12 S. suis isolates. In the checkerboard assay, the TET/GML-12 combination exhibited synergistic and additive effects against S. suis isolates (n = 12). In vitro time-killing assays and in vivo therapeutic experiments were used to confirm the synergistic effect of the TET/GML-12 combination against S. suis strains screened based on an FICI ≤ 0.5. In time-killing assays, the TET/GML-12 combination showed a synergistic effect or an additive effect against three isolates with a bacterial reduction of over 2.4-log10 CFU/mL compared with the most active monotherapy. Additionally, the TET/GML-12 combination displayed potent antimicrobial activity against four isolates in a mouse thigh infection model. These results suggest that the TET/GML-12 combination may be a potential therapeutic strategy for S. suis infection.

Prevalence and Etiology of Community-acquired Pneumonia in Immunocompromised Patients.

BACKGROUND: The correct management of immunocompromised patients with pneumonia is debated. We evaluated the prevalence, risk factors, and characteristics of immunocompromised patients coming from the community with pneumonia. METHODS: We conducted a secondary analysis of an international, multicenter study enrolling adult patients coming from the community with pneumonia and hospitalized in 222 hospitals in 54 countries worldwide. Risk factors for immunocompromise included AIDS, aplastic anemia, asplenia, hematological cancer, chemotherapy, neutropenia, biological drug use, lung transplantation, chronic steroid use, and solid tumor. RESULTS: At least 1 risk factor for immunocompromise was recorded in 18% of the 3702 patients enrolled. The prevalences of risk factors significantly differed across continents and countries, with chronic steroid use (45%), hematological cancer (25%), and chemotherapy (22%) the most common. Among immunocompromised patients, community-acquired pneumonia (CAP) pathogens were the most frequently identified, and prevalences did not differ from those in immunocompetent patients. Risk factors for immunocompromise were independently associated with neither Pseudomonas aeruginosa nor non-community-acquired bacteria. Specific risk factors were independently associated with fungal infections (odds ratio for AIDS and hematological cancer, 15.10 and 4.65, respectively; both P = .001), mycobacterial infections (AIDS; P = .006), and viral infections other than influenza (hematological cancer, 5.49; P < .001). CONCLUSIONS: Our findings could be considered by clinicians in prescribing empiric antibiotic therapy for CAP in immunocompromised patients. Patients with AIDS and hematological cancer admitted with CAP may have higher prevalences of fungi, mycobacteria, and noninfluenza viruses.

Mainly Post-Transplant Factors Are Associated with Invasive Aspergillosis after Allogeneic Stem Cell Transplantation: A Study from the Surveillance des Aspergilloses Invasives en France and Société Francophone de Greffe de Moelle et de Thérapie Cellulaire.

Invasive aspergillosis (IA) occurs in up to 23% of allogeneic hematopoietic stem cell transplantation (HSCT) patients. Although transplant procedures have changed over time, more late cases of IA are being observed. The objective of this study was to identify the pre- and post-transplant factors of IA in a large cohort of HSCT patients mainly transplanted with reduced-intensity conditioning. This multicenter, case-control study was carried out using data collected between 2005 and 2010 by the Surveillance des Aspergilloses Invasives en France program (Institut Pasteur, Paris) and the European Society for Blood and Marrow Transplantation ProMISe registry. Four control subjects without IA were individually matched to each case based on the center, patient age, and year of the transplant. We identified 185 cases of probable and proven IA and 651 control subjects. The median date of IA after the transplant was 133 days, with 35 cases (19%) of early IA (before day 40), 33 cases (18%) of late IA (days 40 to 100), and 117 cases (63%) cases of very late IA (after day 100). In the multivariate analysis early IA was significantly associated with a lack of engraftment, whereas late and very late IA were significantly associated with more than grade II acute graft-versus-host disease (GVHD); very late IA was also significantly associated with relapse and secondary neutropenia. Two-thirds of IA cases occurred more than 100 days after HSCT with different risk factors from those occurring earlier. Prophylactic strategies should consider the specific risk factors for late and very late IA, especially GVHD, relapse after transplant, and secondary neutropenia.

In Vivo Pharmacodynamics of Omadacycline against Staphylococcus aureus in the Neutropenic Murine Thigh Infection Model.

Omadacycline is a novel aminomethylcycline antibiotic with potent activity against Staphylococcus aureus, including methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA). We investigated the pharmacodynamic activity of omadacycline against 10 MSSA/MRSA strains in a neutropenic murine thigh model. The median 24-h area under the concentration-time curve (AUC)/MIC values associated with net stasis and 1-log kill were 21.9 and 57.7, respectively.