Mini Kamboj

Vancomycin-resistant Enterococcus domination of intestinal microbiota is enabled by antibiotic treatment in mice and precedes bloodstream invasion in humans

Bloodstream infection by highly antibiotic-resistant bacteria, such as vancomycin-resistant Enterococcus (VRE), is a growing clinical problem that increasingly defies medical intervention. Identifying patients at high risk for bacterial sepsis remains an important clinical challenge. Recent studies have shown that antibiotics can alter microbial diversity in the intestine. Here, we characterized these effects using 16s rDNA pyrosequencing and demonstrated that antibiotic treatment of mice enabled exogenously administered VRE to efficiently and nearly completely displace the normal microbiota of the small and large intestine. In the clinical setting, we found that intestinal domination by VRE preceded bloodstream infection in patients undergoing allogeneic hematopoietic stem cell transplantation. Our results demonstrate that antibiotics perturb the normal commensal microbiota and set the stage for intestinal domination by bacteria associated with hospital-acquired infections. Thus, high-throughput DNA sequencing of the intestinal microbiota could identify patients at high risk of developing bacterial sepsis.

The Changing Epidemiology of Vancomycin-Resistant Enterococcus (VRE) Bacteremia in Allogeneic Hematopoietic Stem Cell Transplant (HSCT) Recipients

The impact of the rising prevalence of vancomycin-resistant Enterococcus (VRE) prior to hematopoietic stem cell transplantation (HSCT) and changes in transplant techniques on risk of VREB (VRE bacteremia) early after HSCT is not known. This is a retrospective study of 247 adult patients who underwent allogeneic HSCT in the years 2008 and 2009 at the Memorial Sloan-Kettering Cancer Center. Sixty-eight of 247 (27.5%) patients were VRE colonized on pretransplant screening. VRE was the leading cause of bacteremia in the first 30 days after HSCT; 23 of 43 (53.5%) patients with positive blood cultures had VRE. Only 13 (57%) of the 23 patients with early VREB were colonized with VRE on pre-HSCT screening cultures. Mortality was directly attributable to VRE infection in 9% of patients with early VREB. VRE is emerging as the most common cause of preengraftment bacteremia in patients undergoing allogeneic HSCT, and is associated with substantial mortality. Pre-HSCT screening for VRE with stool cultures will not identify all patients who are at risk for VREB. The use of alternate agents with activity against Gram-positive bacteria for fever and neutropenia early after HSCT should be evaluated further in prospective studies.

The Risk of Tuberculosis in Patients with Cancer

Current US guidelines for the management of latent tuberculosis infection in cancer patients are based on studies from 1970s, yet much about cancer care has changed in the interim. In a review of our experience during the past 25 years, we found that incidence of tuberculosis varied significantly according to country of birth and cancer type. Foreign-born patients with underlying hematologic neoplasm had a tuberculosis rate 50-100 times higher than US-born patients, whereas US-born patients with an underlying solid tumor had the same tuberculosis rate as US-born persons without cancer. These findings may help guide the management of latent tuberculosis infection in persons with cancer.

Comparison of the Luminex xTAG RVP Fast Assay and the Idaho Technology FilmArray RP Assay for Detection of Respiratory Viruses in Pediatric Patients at a Cancer Hospital

ABSTRACT Respiratory viruses are increasingly recognized as serious causes of morbidity and mortality in immunocompromised patients. The rapid and sensitive detection of respiratory viruses is essential for the early diagnosis and administration of appropriate antiviral therapy, as well as for the effective implementation of infection control measures. We compared the performance of two commercial assays, xTAG RVP Fast (Luminex Diagnostics, Toronto, Canada) and FilmArray RVP (FA RVP; Idaho Technology, Salt Lake City, UT), in pediatric patients at Memorial Sloan-Kettering Cancer Center. These assays detect the following viruses: respiratory syncytial virus; influenza A and B viruses; parainfluenza viruses 1, 2, 3, and 4; human metapneumovirus; adenovirus; enterovirus-rhinovirus; coronaviruses NL63, HKU1, 229E, and OC43; and bocavirus. We tested a total of 358 respiratory specimens from 173 pediatric patients previously tested by direct fluorescence assay (DFA) and viral culture. The overall detection rate (number of positive specimens/total specimens) for viruses tested by all methods was 24% for DFA/culture, 45% for xTAG RVP Fast, and 51% for FA RVP. The agreement between the two multiplex assays was 84.5%, and the difference in detection rate was statistically significant (P < 0.0001). Overall, the FA RVP assay was more sensitive than the xTAG RVP Fast assay and had a turnaround time of approximately 1 h. The sensitivity, simplicity, and random-access platform make FA RVP an excellent choice for laboratory on-demand service with low to medium volume.

2009 H1N1 influenza infection in cancer patients and hematopoietic stem cell transplant recipients

OBJECTIVES Although usually mild, 2009 H1N1 Influenza has caused up to 6000 deaths in the US. To determine outcome in patients with cancer and/or hematopoietic stem cell transplant (HSCT), we reviewed our recent experience at Memorial Sloan-Kettering Cancer Center (MSKCC). METHODS During the initial NYC outbreak (May 19-June 30, 2009), all respiratory samples at MSKCC were tested for 2009 H1N1 influenza by DFA, culture, and RT-PCR. Medical records were reviewed for all cases. RESULTS During the 6-week period, 45(11%) of 394 tested patients were diagnosed with 2009 H1N1 Influenza. These included 29(17%) of 167 patients with hematologic conditions compared to 16(7%) of 226 with solid tumors (P < 0.01). 21(22%) of 96 tested HSCT recipients were positive. Cough (93%) and fever (91%) were common. Of 29 patients who were radiographically assessed, 8(27%) had lower airway disease. 17(37%) were hospitalized. None required mechanical ventilation. No deaths were attributed to influenza. All treated patients tolerated antiviral medication. CONCLUSIONS 2009 H1N1 Influenza caused mild symptoms in most patients with cancer and/or HSCT. None died or required mechanical ventilation. Immunosuppression from cancer or its treatment including HSCT may not be a substantial risk for poor outcome, however further studies are needed to validate our results.

Evaluation of the Cepheid Xpert Clostridium difficile Epi assay for diagnosis of Clostridium difficile infection and typing of the NAP1 strain at a cancer hospital.

ABSTRACT Clostridium difficile is the most common cause of health care-associated diarrhea. Accurate and rapid diagnosis is essential to improve patient outcome and prevent disease spread. We compared our two-step diagnostic algorithm, an enzyme immunoassay for glutamate dehydrogenase (GDH) followed by the cytotoxin neutralization test (CYT) with a turnaround time of 24 to 48 h, versus the Cepheid Xpert C. difficile Epi assay, a PCR-based assay with a turnaround time of <1 h. In the first phase of the study, only GDH-positive stool samples were tested by both CYT and Xpert PCR. Discordant results were resolved by toxigenic culture. In the second phase, all stool samples were tested by GDH and Xpert PCR. Only GDH-positive stools were further tested by CYT. Genotypic characterization of 45 Xpert PCR-positive stools was performed by sequencing of the tcdC gene and PCR ribotyping. In phase 1, the agreement between the GDH-CYT and the GDH-Xpert PCR was 72%. The sensitivities and specificities of GDH-CYT and GDH-Xpert PCR were 57% and 97% and 100% and 97%, respectively. In phase 2, the agreement between GDH-CYT and Xpert PCR alone was 95%. As in phase 1, sensitivity of the Xpert PCR was higher than that of the GDH-CYT. The correlation between PCR-ribotyping, sequencing, and Xpert PCR for detection of NAP1 strains was excellent (>90%). The excellent sensitivity and specificity and the rapid turnaround time of the Xpert PCR assay as well as its strain-typing capability make it an attractive option for diagnosis of C. difficile infection.

Relapse Versus Reinfection: Surveillance of Clostridium difficile Infection

Molecular typing was used to examine surveillance definitions for recurrent Clostridium difficile-associated diarrhea. Among 102 patients, 85 had a second episode within 8 weeks, 88% of which were relapses. Of 49 second episodes occurring after > 8 weeks, 65% were relapses. Categorization of a recurrent episode occurring after >8 weeks as a new infection may misrepresent the majority of episodes for surveillance.

Nosocomial infections in patients with cancer

Nosocomial infections are those that become evident 48 h or more after a patient is admitted for treatment in a hospital or in another health-care setting. These infections cause substantial morbidity and mortality in patients who are immunosuppressed. Over the past few decades, understanding of host vulnerability has improved and more rigorous management and infection-control practices have been adopted for treating susceptible populations. Despite efforts, outbreaks continue to occur. In this Review, we outline current knowledge of the incidence and microbiology of various nosocomial infections in patients with cancer-a large, immunosuppressed population.

Emergence of Daptomycin-Resistant VRE: Experience of a Single Institution

Recent surveillance from US hospitals shows that more than 99.5% of vancomycin-resistant enterococci (VRE) isolates remain susceptible to daptomycin. This report describes emergence of daptomycin-resistant VRE at a major cancer center. The percentage of patients with daptomycin-resistant VRE bacteremia increased from 3.4% in 2007 to 15.2% in 2009 ([Formula: see text]). Without susceptibility data, empiric daptomycin therapy for VRE infections should be used with caution.

Clinical characterization of human metapneumovirus infection among patients with cancer

BACKGROUND Human metapneumovirus is a recently discovered RNA virus that typically causes respiratory disease in children. It has been linked to severe lower airway disease in hematopoietic stem cell and solid-organ transplant recipients. hMPV infection in a large population of patients with underlying cancer and varying degrees of immunosuppression has not been reported. We sought to characterize hMPV infection in patients with cancer. METHODS Review of all cases of hMPV infection from two seasons (2005-6 and 2006-7) detected by DFA and/or real-time PCR at MSKCC, a tertiary cancer center in New York City. RESULTS Among MSKCC patients with cancer, 51 (2.7%) of 1899 patients were positive for hMPV, including 3.2% with hematologic neoplasm and 1.7% with solid tumors. More children (4.5%) were positive than adults (2.2%). PCR detected twice as many cases as DFA. Cough and fever were common complaints. The longest shedding period was 80 days. 40 patients received radiographic evaluation; of these, 22 showed abnormalities including patchy (11), ground glass (5), and interstitial infiltrates (4). CONCLUSIONS hMPV causes a nonspecific respiratory illness and was found in more than 2% of all tested persons with cancer. PCR detected substantially more cases than DFA. Unlike previous reports, we observed no fatalities due to hMPV, including 22 HSCT recipients with the infection.