Camille Hamula

Multicenter clinical and molecular epidemiological analysis of bacteremia due to Carbapenem-Resistant Enterobacteriaceae (CRE) in the CRE epicenter of the United States

ABSTRACT Although the New York/New Jersey (NY/NJ) area is an epicenter for carbapenem-resistant Enterobacteriaceae (CRE), there are few multicenter studies of CRE from this region. We characterized patients with CRE bacteremia in 2013 at eight NY/NJ medical centers and determined the prevalence of carbapenem resistance among Enterobacteriaceae bloodstream isolates and CRE resistance mechanisms, genetic backgrounds, capsular types (cps), and antimicrobial susceptibilities. Of 121 patients with CRE bacteremia, 50% had cancer or had undergone transplantation. The prevalences of carbapenem resistance among Klebsiella pneumoniae, Enterobacter spp., and Escherichia coli bacteremias were 9.7%, 2.2%, and 0.1%, respectively. Ninety percent of CRE were K. pneumoniae and 92% produced K. pneumoniae carbapenemase (KPC-3, 48%; KPC-2, 44%). Two CRE produced NDM-1 and OXA-48 carbapenemases. Sequence type 258 (ST258) predominated among KPC-producing K. pneumoniae (KPC-Kp). The wzi154 allele, corresponding to cps-2, was present in 93% of KPC-3-Kp, whereas KPC-2-Kp had greater cps diversity. Ninety-nine percent of CRE were ceftazidime-avibactam (CAZ-AVI)-susceptible, although 42% of KPC-3-Kp had an CAZ-AVI MIC of ≥4/4 μg/ml. There was a median of 47 h from bacteremia onset until active antimicrobial therapy, 38% of patients had septic shock, and 49% died within 30 days. KPC-3-Kp bacteremia (adjusted odds ratio [aOR], 2.58; P = 0.045), cancer (aOR, 3.61, P = 0.01), and bacteremia onset in the intensive care unit (aOR, 3.79; P = 0.03) were independently associated with mortality. Active empirical therapy and combination therapy were not associated with survival. Despite a decade of experience with CRE, patients with CRE bacteremia have protracted delays in appropriate therapies and high mortality rates, highlighting the need for rapid diagnostics and evaluation of new therapeutics.

T2Candida Provides Rapid and Accurate Species Identification in Pediatric Cases of Candidemia.

OBJECTIVES The goal of this study is to assess the ability of the T2Candida platform (T2 Biosystems, Lexington, MA) to accurately identify Candida species from pediatric blood specimens with low volumes. METHODS Whole blood from 15 children with candidemia was collected immediately following blood culture draw. The amount of blood required by the system was reduced by pipetting whole blood directly onto the T2Candida cartridge. Specimens were subsequently run on the T2Dx Instrument (T2 Biosystems). RESULTS The T2Candida panel provided the appropriate result for each specimen compared with blood culture-based species identification and correctly identified 15 positive and nine negative results in 3 to 5 hours. While the time to species identification for blood culture was not reported, the T2Candida results include species data. CONCLUSIONS T2Candida can be used to efficiently diagnose or rule out candidemia using low-volume blood specimens from pediatric patients. This could result in improved time to appropriate antifungal therapy or reduction in unnecessary empirical antifungal therapy.

Whole-genome sequencing identifies emergence of a quinolone resistance mutation in a case of Stenotrophomonas maltophilia bacteremia.

ABSTRACT Whole-genome sequences for Stenotrophomonas maltophilia serial isolates from a bacteremic patient before and after development of levofloxacin resistance were assembled de novo and differed by one single-nucleotide variant in smeT, a repressor for multidrug efflux operon smeDEF. Along with sequenced isolates from five contemporaneous cases, they displayed considerable diversity compared against all published complete genomes. Whole-genome sequencing and complete assembly can conclusively identify resistance mechanisms emerging in S. maltophilia strains during clinical therapy.

First Report of Wohlfahrtiimonas chitiniclastica Isolation from a Patient with Cellulitis in the United States

ABSTRACT We report the first documented isolation of Wohlfahrtiimonas chitiniclastica from a human in the United States. Initially misidentified as Acinetobacter lwoffii by Vitek-2, the isolate was subsequently identified as W. chitiniclastica by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. While the clinical significance of the isolate in this case is unclear, it highlights the superior performance of MALDI-TOF MS for bacterial identification.

Genomic confirmation of vancomycin-resistant Enterococcus transmission from deceased donor to liver transplant recipient

In a liver transplant recipient with vancomycin-resistant Enterococcus (VRE) surgical site and bloodstream infection, a combination of pulsed-field gel electrophoresis, multilocus sequence typing, and whole genome sequencing identified that donor and recipient VRE isolates were highly similar when compared to time-matched hospital isolates. Comparison of de novo assembled isolate genomes was highly suggestive of transplant transmission rather than hospital-acquired transmission and also identified subtle internal rearrangements between donor and recipient missed by other genomic approaches. Given the improved resolution, whole-genome assembly of pathogen genomes is likely to become an essential tool for investigation of potential organ transplant transmissions.

Retrospective report of antimicrobial susceptibility observed in bacterial pathogens isolated from ocular samples at Mount Sinai Hospital, 2010 to 2015

BackgroundAntimicrobial resistance has emerged as a major threat to global public health. Thus, the surveillance of changes in antimicrobial resistance in local and global settings is a paramount necessity. While many studies have tracked antimicrobial resistance, only a small percentage surveyed ocular isolates. The purpose of this study was to report the in vitro susceptibility of bacterial pathogens isolated from ocular samples in New York, NY from 2010 to 2015.MethodsA retrospective review of ocular isolates was conducted. All organisms were collected by 25 separate inpatient wards and outpatient clinics, and were analyzed by the clinical microbiology laboratory at Mount Sinai Hospital. Clinical Laboratory and Standards Institute (CLSI) guidelines were followed for susceptibility testing and breakpoint interpretations.ResultsA total of 549 bacterial organisms were isolated from 1664 cultures (33%) during the 6-year study period. Of these, 358 isolates (65.2%) underwent susceptibility testing. 182 (50.8%) isolates were Gram-positive. The most common Gram-positive bacterium was Staphylococcus aureus (62.1%). Methicillin-resistance decreased in S. aureus isolates (31.3% in 2010, 14.1% in 2015) but was without significant change (p = 0.25). When analyzing all S. aureus isolates recovered during the study period, there were significantly more methicillin-resistant S. aureus (MRSA) isolates resistant to fluoroquinolones (p <0.0001), erythromycin (p <0.0001), and trimethoprim/sulfamethoxazole (TMP/SMZ; p <0.05). Overall, Streptococcus pneumoniae isolates showed reduced susceptibility to erythromycin, but were otherwise susceptible to the other antimicrobials tested. Haemophilus influenzae (26.1%) and Pseudomonas aeruginosa (23.9%) were the most common Gram-negative bacteria isolated. Resistance to ampicillin and TMP/SMZ was observed in several of the H. influenzae isolates. P. aeruginosa isolates did not show high resistance overall, however, it was noted that isolates resistant to meropenem were also resistant to other antimicrobials (p < 0.01).ConclusionOverall, antimicrobial resistance was infrequent for the Gram-negative and Gram-positive bacteria analyzed. While the MRSA isolates demonstrated increased resistance to multiple antimicrobial classes, this is expected for this pathogen. Due to the continued use of broad-spectrum oral and systemic antimicrobials to treat ocular infections, findings of this study and other surveillance studies specific to ocular isolates should be used as resources in effective decision making in the treatment of ocular disease.

Genetic Basis of Emerging Vancomycin, Linezolid, and Daptomycin Heteroresistance in a Case of Persistent Enterococcus faecium Bacteremia

ABSTRACT Whole-genome sequencing was used to examine a persistent Enterococcus faecium bacteremia that acquired heteroresistance to three antibiotics in response to prolonged multidrug therapy. A comparison of the complete genomes before and after each change revealed the emergence of known resistance determinants for vancomycin and linezolid and suggested that a novel mutation in fabF, encoding a fatty acid synthase, was responsible for daptomycin nonsusceptibility. Plasmid recombination contributed to the progressive loss of vancomycin resistance after withdrawal of the drug.

A case of Strongyloides hyperinfection syndrome in the setting of persistent eosinophilia but negative serology

Strongyloides stercoralis is a unique intestinal nematode with the ability to replicate and complete its life cycle without leaving the host. We report a fatal case of Strongyloides hyperinfection syndrome in a patient who had persistent eosinophilia for several years but negative Strongyloides serology. Our case suggests that ELISA serologies cannot solely be relied upon to diagnose Strongyloides stercoralis infection; history and clinical judgment remain crucial to this diagnosis.

Community-Acquired Cavitary Pseudomonas Pneumonia Linked to Use of a Home Humidifier

Pseudomonas aeruginosa is an opportunistic pathogen that rarely causes pneumonia in otherwise healthy patients. We describe a case of community-acquired P. aeruginosa pneumonia in a previously healthy individual who likely acquired the infection from a home humidifier.

Report of two paediatric cases of central line infections caused by species of the genus Kocuria

Introduction: Species of the genus Kocuria are Gram-positive cocci of the family Micrococcacceae that are ubiquitous in the environment and part of the normal skin and oral flora in humans. A paucity of cases have been reported of Kocuria as human pathogens and there are currently no evidence-based guidelines for managing these uncommon infections. Case presentation: We present two paediatric cases of central line infections with species of the genus Kocuria that required line removal despite antimicrobial therapy. Conclusion: Species of the genus Kocuria are uncommon human pathogens that have rarely been reported to cause opportunistic infections in both adult and paediatric populations. The cases presented here add to the growing body of literature documenting the pathogenicity of these organisms and the possible need for line removal to achieve clinical cure in central line-associated bacteraemia caused by species of the genus Kocuria.