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Clostridioides difficile (formerly known as Clostridium difficile (1)) infection (CDI) is the world-leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis. (2) Clostridioides difficile can cause a wide spectrum of [...], * Context.--Clostridioides difficile infection (CDI) is the world-leading cause of infectious nosocomial diarrhea and pseudomembranous colitis. Antibiotics are the first line of treatment against CDI despite the high likelihood of antibiotic failure and/or recurrence. More data are needed to correlate clinical variables with 16S rRNA microbiome profiles in CDI-infected patients. Objective.--To determine the relationship(s) between a patient's clinical factors and the stool bacteriome of CDI-positive patients and CDI-negative patients with diarrheal symptoms. Design.--This study used stool samples and clinical data from 358 patients with nosocomial diarrhea, who were divided by their CDI diagnosis (CDI-negative: n = 180; CDI-positive; n = 178). The stool bacteriome was profiled by amplicon deep sequencing of the 16S rRNA gene, followed by correlating clinical data. Results.--The stool bacteriome was significantly different by severity assessment regardless of CDI status. Phyla and species varied significantly by CDI diagnosis. Severity, defined as a serum white blood cell count greater than 15 cells/[micro]L and/or a creatinine level greater than 1.5 mg/dL, correlated significantly with dysbiosis of the stool bacteriome profile of CDI-positive patients compared to CDI-negative patients. Serum white blood cell count was significantly higher in patients with bacterial dysbiosis, and high levels of creatinine were associated with low bacteriome diversity. Conclusions.--Clinical severity of CDI influences the stool microbiome of infected patients. To date, this study has the largest data set comparing 16S rRNA microbiome profiles and clinical variables between CDI-infected and noninfected individuals. (Arch Pathol Lab Med. 2023;147:774-785; doi: 10.5858/ arpa.2021-0636-OA)

Reverse transcriptase-polymerase chain reaction (RTPCR) is the standard method of diagnosing COVID19 in a laboratory. (1-4) RT-PCR tests for COVID-19 qualitatively detect SARS-CoV-2 RNA from patient samples. (1-4) SARS-CoV-2 is [...], Context.--Reverse transcription-polymerase chain reaction (RT-PCR) is the standard method of diagnosing COVID-19. An inconclusive test result occurs when 1 RT-PCR target is positive for SARS-CoV-2 and 1 RT-PCR target is negative for SARS-CoV-2 within the same sample. An inconclusive result generally requires retesting. One reason why a sample may yield an inconclusive result is that one target is at a higher concentration than another target. Objective.--To understand the role of subgenomic RNA transcripts in discordant results from RT-PCR tests for COVID-19. Design.--A panel of 6 droplet digital PCR assays was designed to quantify the ORF1, E-gene, and N-gene of SARS-CoV-2. This panel was used to quantify viral cultures of SARS-CoV-2 that were harvested during the eclipse phase and at peak infectivity. Eleven clinical nasopharyngeal swabs were also tested with this panel. Results.--In culture, infected cells showed higher Ngene/ORF1 copy ratios than culture supernatants. The same trends in the relative abundance of copies across different targets observed in infected cells were observed in clinical samples, although trends were more pronounced in infected cells. Conclusions.--This study showed that a greater copy number of N-gene relative to E-gene and ORF1 transcripts could potentially explain inconclusive results for some RTPCR tests on low viral load samples. The use of N-gene RTPCR target(s) as opposed to ORF1 targets for routine testing is supported by these data.

Malaria elimination relies on detection of Plasmodium falciparum histidine-rich proteins 2/3 (HRP2/3) through rapid diagnostic tests (RDTs) and treatment with artemisinin combination therapies (ACTs). Data from the Horn of Africa suggest increasing hrp2/3 gene deletions and ACT partial resistance kelch13 (k13) mutations. To assess this, 233 samples collected during a national survey from 7 regions of Ethiopia were studied for hrp2/3 deletions with droplet digital polymerase chain reaction (ddPCR) and k13 mutations with DNA sequencing. Approximately 22% of the study population harbored complete hrp2/3 deletions by ddPCR. Thirty-two of 44 of k13 single-nucleotide polymorphisms identified were R622I associated with ACT partial resistance. Both hrp2/3 deletions and k13 mutations associated with ACT partial resistance appear to be co-occurring, especially in Northwest Ethiopia. Ongoing national surveillance relying on accurate laboratory methods are required to elaborate the genetic diversity of P. falciparum. [ABSTRACT FROM AUTHOR]

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious agent, with the propensity to cause severe respiratory illness. At the time of this writing, the global coronavirus [...], * Context.--The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious agent, with the propensity to cause severe illness. While vaccine uptake has been increasing in recent months, many regions remain at risk of significant coronavirus disease 19 (COVID-19)-related health care burden. Health systems will continue to benefit from the availability of a variety of clinical and laboratory models when other triaging models are equivocal. Objective.--To validate previously reported clinical laboratory abnormalities seen in COVID-19 patients and identify what laboratory parameters might be outcome predictive. Design.--We undertook an observational study of hospital-admitted COVID-19 patients (n = 113), looking at a broad selection of clinical, laboratory, peripheral blood smear, and outcome data during discrete discovery and validation periods from March 2020 to November 2020. Results.--We confirmed the findings of previous studies noting derangement of a variety of laboratory parameters in COVID-19 patients, including peripheral blood morphologic changes. We also devised a simple-to-use decision tree by which patients could be risk stratified on the basis of red blood cell count, creatinine, urea, and atypical plasmacytoid lymphocyte ("covidocyte") count. This outcome classifier performed comparably to the World Health Organization clinical classifier and the neutrophil-lymphocyte ratio. Conclusions.--Our data add to the increasing number of studies cataloguing laboratory changes in COVID-19 and support the clinical utility of incorporating blood morphologic assessment in the workup of hospitalized COVID-19 patients.

Entamoeba histolytica and Giardia lamblia are anaerobic protozoan parasites that cause amebiasis and giardiasis, two of the most common diarrheal diseases worldwide. Current therapy relies on metronidazole, but resistance has been reported and the drug has significant adverse effects. Therefore, it is critical to search for effective, better-tolerated antiamebic and antigiardial drugs. We synthesized several examples of a recently reported class of Hsp90 inhibitors and evaluated these compounds as potential leads for antiparasitic chemotherapy. Several of these inhibitors showed strong in vitro activity against both E. histolytica and G. lamblia trophozoites. The inhibitors were rescreened to discriminate between amebicidal and giardicidal activity and general cytotoxicity toward a mammalian cell line. No mammalian cytotoxicity was found at >100 μM for 48 h for any of the inhibitors. To understand the mechanism of action, a competitive binding assay was performed using the fluorescent ATP analogue bis-ANS (4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfonic acid dipotassium salt) and recombinant E. histolytica Hsp90 preincubated in both the presence and absence of Hsp90 inhibitors. There was significant reduction in fluorescence compared to the level in the control, suggesting that E. histolytica Hsp90 is a selective target. The in vivo efficacy and safety of one Hsp90 inhibitor in a mouse model of amebic colitis and giardiasis was demonstrated by significant inhibition of parasite growth at a single oral dose of 5 mg/kg of body weight/day for 7 days and 10 mg/kg/day for 3 days. Considering the results for in vitro activity and in vivo efficacy, Hsp90 inhibitors represent a promising therapeutic option for amebiasis and giardiasis.

In Haiti (2011 population ≅9.7 million), malaria is endemic. Approximately 30,000 malaria infections are confirmed annually among ≅200,000 estimated malaria cases, mainly Plasmodium falciparum infections (1). On January 12, 2010, [...]

Malaria is a parasitic, vector-borne disease that causes ≅ 1 million deaths each year and substantial global public health costs (1,2). The disease was previously endemic in North America, with [...]

Salmonella enterica serovar Heidelberg ranks among the top 3 serovars isolated from persons infected with Salmonella in Canada (1). It is more frequently reported in North America than in other [...]