Cryptosporidiosis, a zoonosis caused by Cryptosporidium species, is a newly recognized coccidial protozoan infection causing severe protracted watery diarrhea in humans. In August 1981, the first case of cryptosporidiosis in a homosexual man with acquired immune deficiency syndrome (AIDS) was reported; diagnosis was determined by intestinal biopsy. It is necessary to adopt a simple laboratory diagnostic procedure to screen large numbers of suspected cases. A three-step stool examination was developed to demonstrate Cryptosporidium oocysts and the diagnostic and infective stages of the infection in 10 homosexual men with AIDS. This is a less invasive, less costly, and more sensitive test than intestinal biopsy and has been designed to prevent confusion caused by yeast cells that are frequently present in stool, leading to a false diagnosis. The examination consists of preliminary differential determination by iodine wet mount, definitive identification by modified Kinyoun acid-fast staining, and a more effective method of concentrating oocysts, by Sheather's sugar cover-slip flotation method.
Objectives To determine the prevalence, risk factors, treatments, and outcomes of bloodstream infections (BSIs) due to carbapenem-resistant Enterobacteriaceae (CRE) in adult neutropenic patients with hematologic malignancies. Methods We reviewed all BSIs between 2008–2012 in this population at two New York City oncology centers. A case-control study was conducted to identify CRE BSI risk factors, using three controls of non-CRE BSIs per case. Results CRE caused 43 (2.2%) of 1,992 BSIs overall and 4.7% of Gram-negative bacteremias. Independent risk factors for CRE BSI were prior β-lactam/β-lactamase inhibitor (adjusted odds ratio [aOR] 3.2; P=0.03) or carbapenem (aOR 3.0; P=0.05) use, current trimethoprim-sulfamethoxazole (aOR 24; P=0.001) or glucocorticoid (aOR 5.4, P=0.004) use, and having a prior CRE culture (aOR 12; P=0.03). Patients with CRE bacteremia had a median of 52 hours from culture collection until receipt of active therapy. They had a 51% BSI-related mortality rate, with a median of 4 days from bacteremia onset until death. CRE-active empirical therapy was associated with a lower 30-day mortality rate (17% vs. 59%; P=0.08). Conclusions CRE are lethal emerging causes of bacteremia in neutropenic patients. New strategies are needed to shorten the delay in administration of CRE-active agents and improve outcomes in this vulnerable population.
Carbapenem-resistant Enterobacteriaceae (CRE) are increasingly prevalent pathogens. However, little is known about their emergence in patients with hematologic malignancies. We identified 18 patients with hematologic malignancies over 3.5 years who developed bloodstream infections (BSIs) caused by CRE. Fourteen BSIs were caused by Klebsiella pneumoniae, three by Enterobacter cloacae, and one was polymicrobial. Initial empirical antimicrobial therapy was active in two patients (11%), and a median of 55 h elapsed between culture collection and receipt of an active agent. Ten patients (56%) died, including nine (69%) of 13 neutropenic patients, with a median of 4 days from culture collection until death. CRE isolates were analyzed for carbapenemase production, β-lactamase genes and outer membrane porin deletions and characterized by multilocus sequence typing and pulsed-field gel electrophoresis (PFGE). Carbapenem resistance mechanisms included Klebsiella pneumoniae carbapenemase production and CTX-M-15 production with an absent outer membrane porin protein. No isolate had ≥95% homology on PFGE, indicating a heterogeneous, non-outbreak population of isolates. CRE BSIs are emerging in patients with hematologic malignancies and are associated with ineffective initial empirical therapy, long delays in administration of active antimicrobials and high mortality rates. New diagnostic, therapeutic and preventive strategies for CRE infections in this vulnerable population are needed.
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