Gut microbiome modulates response to anti-PD-1 immunotherapy in melanoma patients

Preclinical mouse models suggest that the gut microbiome modulates tumor response to checkpoint blockade immunotherapy; however, this has not been well-characterized in human cancer patients. Here we examined the oral and gut microbiome of melanoma patients undergoing anti-programmed cell death 1 protein (PD-1) immunotherapy (n = 112). Significant differences were observed in the diversity and composition of the patient gut microbiome of responders versus nonresponders. Analysis of patient fecal microbiome samples (n = 43, 30 responders, 13 nonresponders) showed significantly higher alpha diversity (P < 0.01) and relative abundance of bacteria of the Ruminococcaceae family (P < 0.01) in responding patients. Metagenomic studies revealed functional differences in gut bacteria in responders, including enrichment of anabolic pathways. Immune profiling suggested enhanced systemic and antitumor immunity in responding patients with a favorable gut microbiome as well as in germ-free mice receiving fecal transplants from responding patients. Together, these data have important implications for the treatment of melanoma patients with immune checkpoint inhibitors.

Aerosolized ribavirin: the most expensive drug for pneumonia

Dramatic, overnight cost increases of important orphan and generic medications have recently come under public and government scrutiny. We highlight the case of aerosolized ribavirin, an important antiviral agent in hematopoietic stem cell transplantation which, because of substantial price increases, may now cost more than the transplant procedure itself.

Outcomes for and Risk Factors Associated With Vancomycin-ResistantEnterococcus faecalisand Vancomycin-ResistantEnterococcus faeciumBacteremia in Cancer Patients

Objective.

Vancomycin-resistant enterococci (VRE) are a major cause of nosocomial infection. We sought to compare vancomycin-resistant (VR)Enterococcus faecalisbacteremia and VREnterococcus faeciumbacteremia in cancer patients with respect to risk factors, clinical presentation, microbiological characteristics, antimicrobial therapy, and outcomes.

Methods.

We identified 210 cancer patients with VRE bacteremia who had been treated between January 1996 and December 2004; 16 of these 210 had VRE. faecalisbacteremia and were matched with 32 patients with VRE. faeciumbacteremia and 32 control patients. A retrospective review of medical records was conducted.

Results.

Logistic regression analysis showed that, compared with VRE. faecalisbacteremia, VRE. faeciumbacteremia was associated with a worse clinical response to therapy (odds ratio [OR], 0.3 [95% confidence interval (CI), 0.07-0.98];P= .046) and a higher overall mortality rate (OR, 8.3 [95% CI, 1.9-35.3];P= .004), but the VRE-related mortality rate did not show a statistically significant difference (OR, 6.8 [95% CI, 0.7-61.8];P= .09). Compared with control patients, patients with VRE. faecalisbacteremia were more likely to have received an aminoglycoside in the 30 days before the onset of bacteremia (OR, 5.8 [95% CI, 1.2-27.6];P= .03), whereas patients with VRE. faeciumbacteremia were more likely to have received a carbapenem in the 30 days before the onset of bacteremia (OR, 11.7 [95% CI, 3.6-38.6];P<.001). In a multivariate model that compared patients with VRE. faeciumbacteremia and control patients, predictors of mortality included acute renal failure on presentation (OR, 15.1 [95% CI, 2.3-99.2];P= .004) and VRE. faeciumbacteremia (OR, 11 [95% CI, 2.7-45.1];P<.001). No difference in outcomes was found between patients with VRE. faecalisbacteremia and control patients.

Conclusions.

VRE. faeciumbacteremia in cancer patients was associated with a poorer outcome than was VRE. faecalisbacteremia. Recent receipt of carbapenem therapy was an independent risk factor for VRE. faeciumbacteremia, and recent receipt of aminoglycoside therapy was independent risk factor forE. faecalisbacteremia.

Fecal colonization and infection with Pseudomonas aeruginosa in recipients of allogeneic hematopoietic stem cell transplantation

BACKGROUND

Pseudomonas aeruginosa, especially multidrug-resistant (MDR) isolates, is an important pathogen in allogeneic hematopoietic stem cell transplant (HCT) recipients. The ability to identify patients at risk for these infections and administer appropriate empiric therapy, particularly during episodes of neutropenia, may improve outcomes and also direct infection control and antimicrobial stewardship efforts. Many transplant centers obtain routine surveillance stool cultures (SSCs) from HCT recipients to test for colonization with vancomycin-resistant enterococci, and extended-spectrum beta lactamase-producing Enterobacteriaceae. Our center initiated the performance of SSCs for P. aeruginosa, because of a perceived increase in the frequency of infection with MDR strains. The aim of this study was to determine the utility of this practice.

METHODS

We conducted a 2-year (2010-2011) retrospective review of the medical records of all patients who underwent allogeneic HCT at our cancer center to (a) determine the frequency of fecal colonization with P. aeruginosa, including MDR strains; (b) to determine the overall frequency of subsequent P. aeruginosa infection, as well as the frequency of infection with MDR strains; (c) to ascertain the proportion of subsequent infections likely arising from the intestinal tract; and (d) to determine risk factors for progression from colonization to infection.

RESULTS

Of 794 study patients, 58 (7.3%) had at least 1 positive SSC for P. aeruginosa; 19/58 (32.8%) developed a subsequent pseudomonal infection (11 with matching antimicrobial resistance patterns). On the other hand, 37/736 (5%) of the patients who were not colonized, developed a pseudomonal infection. The type of infection observed was pneumonia in 26 (46%) patients, bloodstream infection in 20 (36%), urinary tract infection in 8 (14%), and infections at other sites in 2 (4%). The incidence of MDR P. aeruginosa in the entire cohort was 2.2% (18 of 794): 12 had positive SSCs and 7 of these patients later developed MDR P. aeruginosa infections. Patients with acute myelogenous leukemia were more likely to be colonized and to develop subsequent infection. No infection-related deaths were observed during the first 30 days after infection.

CONCLUSIONS

The incidence of P. aeruginosa colonization and subsequent infection was low. Patients who were not colonized had a low chance of developing P. aeruginosa infection. Most patients who developed infection did not have fecal colonization, suggesting a different source of infection. SSCs for P. aeruginosa provide incomplete information regarding the source of infection.

Vaccination guidelines after hematopoietic stem cell transplantation: practitioners' knowledge, attitudes, and gap between guidelines and clinical practice

BACKGROUND

Hematopoietic stem cell transplant (HCT) recipients are more susceptible to infections from vaccine-preventable diseases than the general population. Despite the development of international consensus guidelines addressing immunization after HCT, studies have shown that deviations from recommended immunization practices commonly occur.

METHODS

An anonymous survey aimed at determining awareness of the guidelines and attitudes toward vaccination was distributed to our HCT clinicians. In parallel, we retrospectively evaluated patients' characteristics and post-HCT vaccine administration practices from 2010 to 2013.

RESULTS

The majority of survey respondents (96%) were familiar with post-HCT vaccination protocols. Seventy-four percent of respondents reported that influenza vaccines were given to >70% of their patients, and 41% stated that they prescribed live vaccines to eligible patients. However, our pharmacy database review revealed that 38% of patients received the first series of vaccinations by the recommended 6 months post HCT, and 60% received them by 1 year after HCT. Most patients who had their vaccines withheld had relapsed disease or were undergoing treatment for graft-versus-host disease. Furthermore, we identified lower immunization rates in non-English speaking individuals, African-Americans, and Hispanic patients.

CONCLUSIONS

Survey respondents reported being aware of current guidelines; however, adherence to the recommendations varied, likely connected to conflicting data on vaccine effectiveness and a lack of clear recommendations in complex clinical scenarios. Similar to the general population, patient barriers also could have contributed to lower vaccination rates in some cases. To decrease the large gap between the post-HCT vaccination guidelines and clinical practice, further studies on vaccine effectiveness and specific populations are warranted.

Adenoviral infections in adult allogeneic hematopoietic SCT recipients: a single center experience

Disseminated adenoviral infection (AI) is associated with profound immunosuppression and poor outcome after allogeneic hematopoietic SCT (allo-HSCT). A better understanding of AI in allo-HSCT recipients can serve as a basis to develop more effective management strategies. We evaluated all adult patients who received allo-HSCT at MD Anderson Cancer Center between 1999 and 2008. Among the 2879 allo-HSCT patients, 73 (2.5%) were diagnosed with AI. Enteritis (26%) and pneumonia (24%) were the most common clinical manifestations; pneumonia was the most common cause of adenovirus-associated death. A multivariable Bayesian logistic regression showed that when the joint effects of all covariates were accounted for, cord blood transplant, absolute lymphocyte count (ALC) ≤ 200/mm(3) and male gender were associated with a higher probability of disseminated AI. The OS was significantly worse for patients with AI that was disseminated rather than localized (median of 5 months vs median of 28 months, P<0.001) and for patients with ALC ≤ 200/mm(3) (P<0.001). Disseminated AI, in patients who received allo-HSCT, is a significant cause of morbidity and mortality. Strategies for early diagnosis and intervention are essential, especially for high-risk patients.

Abstract P4-15-02: Timing of infectious complications following breast conserving therapy with catheter-based accelerated partial breast irradiation

Background: Accelerated partial breast irradiation (APBI) has been introduced as an alternative to whole breast irradiation as part of breast conserving therapy for selected patients. The long-term outcomes remain under investigation. Previous publications have emphasized early postoperative infections with APBI with less focus on delayed infection. In the current study, we evaluated patients enrolled on a prospective registry trial for infectious complications after treatment with catheter-based APBI.

Methods: Patients who underwent single-entry catheter-based APBI were identified from a single-institution prospective registry from 2009 to 2011. Data regarding treatment, patient comorbidities, complications, and outcomes were obtained from registry and retrospective chart review. Infectious complications were assessed from the date of APBI catheter insertion and were classified as early (≤30 days) or delayed (&gt;30 days). All patients were maintained on oral antibiotics while the catheter was in place.

Results: A total of 91 patients with 92 cases of primary breast cancer were enrolled on a prospective registry at a comprehensive cancer center between 2009 and 2011 and treated with single-entry catheter-based APBI. The median follow-up time was 76.2 weeks. A temporary catheter was placed at the time of initial operation in 40 cases (43.5%) and left in place a median of 6 days prior to definitive catheter insertion. There were 20 patients (21.7%) who required re-excision. Overall, breast infection occurred in 13 (14.1%) patients. Three (3.3%) patients had infection within 30 days of catheter placement and 10 (10.9%) occurred more than 30 days after catheter insertion (median 112.5 days, interquartile range 51–154). Eight patients were managed with oral antibiotics alone on an outpatient basis. The remainder required a combination of admission, intravenous antibiotics, and aspiration of abscess. One patient underwent operative drainage.

Conclusion: We found an overall infection rate of 14.1% in patients treated with catheter-based APBI. This is consistent with other reports; however, we found that the majority of infections occurred more than 30 days after definitive catheter placement. Vigilance for infectious complications must continue beyond the immediate treatment period in patients undergoing catheter-based APBI. Most infections following APBI can be managed on an outpatient basis without operative intervention.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-15-02.

The efficacy of catheters coated with minocycline and rifampin in the prevention of catheter-related bacteremia in cancer patients receiving high-dose interleukin-2

High-dose interleukin-2 (HDIL-2) has proven to be an effective treatment for metastatic renal cell carcinoma and melanoma. Previous studies have shown an increase in catheter-related bacteremia (CRB) in patients on HDIL-2. The primary objective of this study was to evaluate the effectiveness of minocycline and rifampin-coated catheters (M/R-C) in reducing CRB in cancer patients on HDIL-2. This was a retrospective study where non-coated catheters (NC-C) and M/R-C were used for the administration of HDIL-2 before and after December 2004, respectively. Data collected included demographics, cancer type, catheter type, antibiotic prophylaxis, and infection rates. A total of 107 episodes of catheter use for HDIL-2 were evaluated in 78 patients (30 episodes in patients with M/R-C vs. 77 with NC-C). A total of nine episodes of CRB were identified, all in patients with NC-C (M/R-C 0% vs. NC-C 12%; p=0.06). The median time to bacteremia was 11 days (range 1-315 days). A log-rank test showed a trend that the M/R-C group had lower probability of getting CRB than the NC-C group (p=0.06). The use of M/R-C in patients on HDIL-2 therapy for advanced melanoma and renal cell carcinoma may have reduced the risk of CRB to nil. CRB still occurred despite antibiotic prophylaxis in patients with NC-C.

Infections in non-myeloablative hematopoietic stem cell transplantation patients with lymphoid malignancies: spectrum of infections, predictors of outcome and proposed guidelines for fungal infection prevention

The overall risk of infections is lower in patients undergoing non-myeloablative allogeneic stem cell transplantation (NST) than in conventional stem cell transplant recipients. We sought to evaluate conditions associated with increased risk of infections after NST. In 81 patients, 187 infection episodes were noted; chronic lymphocytic leukemia (138 episodes/100 person-years) and recipients of matched unrelated donor graft (128 episodes/100 person-years) had higher risk of infection. Only half of the cytomegalovirus (CMV) infections occurred 31-100 days after transplantation. Most patients with CMV infection were non-neutropenic (100%), had lymphoma (76%), were younger (<55 years; 72%) and had received matched related donor (MRD) graft (72%). However, graft-versus-host disease (GVHD) was present in only 15% of these patients. Seven (78%) of nine invasive fungal infections (IFI) were diagnosed >100 days after NST and were associated with high mortality (78%). Most patients with IFI were also not neutropenic (100%), had received MRD graft (100%), had lymphoma (78%) and were given systemic steroids (78%); unlike CMV infection, 67% of these patients also had GVHD. On the basis of our results, we propose that NST recipients with lymphoma treated with high-dose corticosteroids for GVHD be considered for antifungal prophylaxis or pre-emptive antifungal therapy.

Severe parainfluenza virus type 2 supraglottitis in an immunocompetent adult host: an unusual cause of a paramyxoviridae viral infection

Parainfluenza virus is a major cause of respiratory illness in humans, manifesting from mild upper respiratory tract infection to bronchiolitis and pneumonia, especially in children. We report - to our knowledge - the first case of a nonimmunocompromised adult patient with human parainfluenza type 2 supraglottitis immediately after returning from China.

Anti-adherence activity and antimicrobial durability of anti-infective-coated catheters against multidrug-resistant bacteria

OBJECTIVES

To investigate the anti-adherence and antimicrobial durability of anti-infective catheters against multidrug-resistant (MDR) Staphylococcus aureus (resistant to vancomycin, rifampicin and methicillin) and MDR Gram-negative bacteria (Stenotrophomonas maltophilia, Acinetobacter baumannii/calcoaceticus and Enterobacter agglomerans) that are often associated with catheter-related bloodstream infections (CRBSIs).

METHODS

Catheters impregnated with minocycline and rifampicin (M/R) or with silver-platinum and carbon (SPC) or with chlorhexidine and silver sulfadiazine (CHX/SS) were compared with non-coated catheters. Adherence of organisms was tested by using an established biofilm colonization model. All isolates were rifampicin-resistant. Antimicrobial durability was tested by soaking 1 cm segments of the catheter in serum and determining zones of inhibition against the tested organisms at weekly intervals.

RESULTS

The M/R catheters showed significantly superior anti-adherence activity and more prolonged antimicrobial durability when compared with CHX/SS-central venous catheter (CVC), SPC-CVC and uncoated control catheters against MDR and vancomycin-resistant S. aureus (MDR VRSA) (all P values < or = 0.02), MDR S. maltophilia (all P values < 0.005) and MDR A. baumannii/calcoaceticus (all P values < 0.002), respectively. M/R-CVC and CHX/SS-CVC had comparable anti-adherence and antimicrobial durability against MDR E. agglomerans, and these two were superior to SPC-CVC and the uncoated control catheters (all P values < 0.001).

CONCLUSIONS

M/R-CVC demonstrated superior anti-adherence activity and more prolonged antimicrobial durability when compared with other approved anti-infective catheters against MDR VRSA and/or MDR Gram-negative bacteria that are often associated with CRBSIs. This finding could explain their efficacy and better performance in clinical studies.

The role of vitamin B6 in the prevention of haematological toxic effects of linezolid in patients with cancer

BACKGROUND

Linezolid is the first approved synthetic oxazolidinone with activity against multidrug-resistant gram-positive pathogens. However, haematological toxic effects of linezolid frequently limit its prolonged use, especially in patients with poor marrow reserves such as those with cancer receiving chemotherapy. Previous authors have reported that administration of vitamin B6 with linezolid reversed pancytopenia in two patients.

METHODS

This is an open-label study of 31 patients with cancer who received linezolid at 600 mg twice daily and vitamin B6 at 50 mg/day for at least 2 weeks mean therapy duration and they were matched to 62 control patients who received linezolid without vitamin B6 to determine whether the concomitant use of vitamin B6 attenuates the haematological toxicity of linezolid in patients with cancer.

RESULTS

Patients were matched according to age, underlying disease, duration of therapy, creatinine level and use of chemotherapy. We found no significant differences in the rate of haematological toxic effects between the two patient groups. The rate of thrombocytopenia was 13% in the vitamin B6 group and 15% in the control group (P = 0.82). Also, the rate of leucopenia was 7% versus 5%, respectively (P = 0.75). None of the patients in the vitamin B6 group had anaemia compared with 5% in the control group.

CONCLUSIONS

Vitamin B6 given at 50 mg/day may have an impact on anaemia but did not prevent linezolid-induced thrombocytopenia or leucopenia in cancer patients.

Sources and outcome of bloodstream infections in cancer patients: the role of central venous catheters

Simultaneously drawn quantitative blood cultures are used to diagnose catheter-related bloodstream infections. We conducted this study to determine the frequency with which central venous catheters were the source of bloodstream infections detected through paired positive blood cultures drawn from cancer patients and the potential for quantitative blood cultures to help predict outcome in neutropenic and non-neutropenic patients. From September 1999 to November 2000, we identified 169 patients with bloodstream infections. Of all bloodstream infections, 56% were catheter-related bloodstream infections. Gram-positive bacteremia was found to be catheter-related in 55% and 69% of patients with hematologic malignancy and solid tumors, respectively, whereas gram-negative bacteremia was catheter-related in only 19% of patients with underlying hematologic malignancy and in 60% of patients with solid tumor (P = 0.01). By multivariate analysis, poor response was associated with critical illness and persistent neutropenia (P < 0.01). In neutropenic patients with catheter-related bloodstream infections, peripheral quantitative blood cultures of >or=100 CFU/mL was also associated with poor response (P = 0.05). Central venous catheters were the major source of bloodstream infection, particularly in patients with solid tumors. In addition to critical illness and persistent neutropenia, quantitative blood cultures might be useful in predicting outcomes for neutropenic patients with catheter-related bloodstream infections.

Oral topical cidofovir: novel route of drug delivery in a severely immunosuppressed patient with refractory multidrug-resistant herpes simplex virus infection

We present a case of serious treatment-refractory acyclovir- and foscarnet-resistant herpes simplex virus (HSV) type-1 orolingual infection that responded to oral cidofovir rinses after failure of acyclovir and foscarnet therapy. The use of 3% cidofovir in a saline rinse for refractory mucosal HSV infection appears promising but needs prospective evaluation.

Risk factors associated with late cytomegalovirus reactivation after allogeneic stem cell transplantation for hematological malignancies

We analyzed the clinical factors associated with late cytomegalovirus (CMV) reactivation in a group of 269 consecutive recipients of allogeneic stem cell transplant (SCT) for hematological malignancies. Eighty-four subjects (31%) experienced late CMV reactivation, including 64 with prior early reactivation and 20 with isolated late reactivation. Multivariate analyses were conducted in patients with early CMV reactivation to identify factors associated with late recurrence. Important risk factors included lymphoid diagnosis, occurrence of graft-versus-host disease (GVHD), greater number of episodes of early reactivation, persistent day 100 lymphopenia and the use of a CMV-seronegative donor graft. We combined these risk factors in a predictive model to identify those at relatively low, intermediate and high risk. The low-risk group (15% cumulative incidence, CI) encompassed patients without early CMV reactivation, and subjects transplanted for a myeloid malignancy from a matched-related (MR) donor without subsequent acute GVHD. The high-risk patients (73% CI) met all of the following criteria: (1) received an MR graft but developed GVHD, or received a non-MR graft irrespective of GVHD; (2) had more than two episodes of early reactivation; and (3) received a CMV-seronegative graft and/or remained persistently lymphopenic at day 100 after SCT. The remaining patients had an intermediate incidence of 32%.

Fungal osteoarticular infections in patients treated at a comprehensive cancer centre: a 10-year retrospective review

This study reviewed retrospectively the clinical characteristics of 28 cancer patients with fungal osteoarticular infections (FOAIs) between 1995 and 2005. Most patients (26; 93%) had haematological malignancies (19 had leukaemia); half (14) were allogeneic stem-cell transplant recipients. Twelve patients (43%) had severe neutropenia (< or = 100/mm3) with a mean duration of 65 days (range 10-500 days), and ten (36%) patients had received a significant dose of corticosteroids. Most (19; 68%) FOAIs were caused by contiguous extension, while nine (32%) were associated with haematogenous spread. Pain, joint instability and local drainage were seen in 28 (100%), six (21%), and seven (25%) patients, respectively. Sixteen (57%) patients had symptoms for < 1 month. The sinuses (ten; 36%) and the vertebral spine (six; 21%) were the most common sites involved. Moulds were the predominant pathogens: Aspergillus fumigatus (two); non-fumigatus Aspergillus spp. (eight); non-specified Aspergillus spp. (three); Fusarium spp. (six); Zygomycetes (five); Scedosporium apiospermum (two); and Exserohilum sp. (one). Candida was the causative pathogen in four cases (including two cases of mixed FOAIs). Arthritis and post-operative FOAIs were both uncommon manifestations, occurring in two patients each. All patients received systemic antifungal therapy (combinations in 20 cases), and 19 cases underwent adjunctive surgery. The crude mortality rates (at 12 weeks) were 44% (9/20) in the patients who underwent surgery and antifungal therapy vs. 33% (2/6) in patients who received antifungal therapy alone (p not significant). FOAI is a rare, yet severe, manifestation of localised or systemic mycoses, caused predominantly by moulds, and is seen typically in patients with haematological malignancies.

Influence of type of cancer and hematopoietic stem cell transplantation on clinical presentation of Pneumocystis jiroveci pneumonia in cancer patients

Pneumocystis jiroveci pneumonia is a common infection in patients with AIDS but an infrequent cause of pneumonia in cancer patients. Little is known about the impact of cancer type and hematopoietic stem cell transplantation on the presentation and outcome of P. jiroveci pneumonia in cancer patients. A retrospective cohort study of all patients with cancer and P. jiroveci pneumonia cared for at The M.D. Anderson Cancer Center during 1990-2003 was conducted. Eighty episodes of P. jiroveci pneumonia in 79 patients were identified. In most (67%) episodes, patients had a hematologic malignancy. In 23 (29%) episodes, patients had undergone hematopoietic stem cell transplantation. Twenty-seven percent of patients with histopathologically confirmed P. jiroveci pneumonia had nodular infiltrates on the radiographic study. Pleural effusion and pneumothorax were more common in patients with hematopoietic stem cell transplantation than in those with solid tumors. Clinical suspicion of P. jiroveci pneumonia was less common in patients with nodular infiltrates than in those without such a radiographic finding (7 vs. 39%; p=0.002). Twenty-six of 76 (34%) patients with data available died of P. jiroveci pneumonia. Predictors of death by univariate analysis included older age, tachypnea, high APACHE II score, use of mechanical ventilation or vasopressors, lower arterial pH level, absence of interstitial component, pneumothorax, and comorbid conditions (all p<0.05). Multivariate analysis identified the use of mechanical ventilation as an independent predictor of death. Death attributable to P. jiroveci pneumonia appeared to be higher in patients with hematopoietic stem cell transplantation. The clinical presentation of P. jiroveci pneumonia in cancer patients may be affected by the category of cancer and the history of hematopoietic stem cell transplantation. P. jiroveci pneumonia remains a rare yet severe infection in cancer patients.

Rapid diagnosis of Histoplasma capsulatum endocarditis using the AccuProbe on an excised valve

Histoplasma capsulatum is an infrequent but serious cause of endocarditis. The definitive diagnosis requires culture, which may require a long incubation. We demonstrated the ability of the Histoplasma capsulatum AccuProbe to accurately identify this organism when applied directly on an excised valve that contained abundant yeast forms consistent with H. capsulatum.