Detection of Pathogenic Bacteria From Septic Patients Using 16S Ribosomal RNA Gene-Targeted Metagenomic Sequencing.

BACKGROUND: Conventional blood cultures were compared to plasma cell-free DNA-based 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR)/next-generation sequencing (NGS) for detection and identification of potential pathogens in patients with sepsis. METHODS: Plasma was prospectively collected from 60 adult patients with sepsis presenting to the Mayo Clinic (Minnesota) Emergency Department from March through August 2019. Results of routine clinical blood cultures were compared to those of 16S rRNA gene NGS. RESULTS: Nineteen (32%) subjects had positive blood cultures, of which 13 yielded gram-negative bacilli, 5 gram-positive cocci, and 1 both gram-negative bacilli and gram-positive cocci. 16S rRNA gene NGS findings were concordant in 11. For the remaining 8, 16S rRNA gene NGS results yielded discordant detections (n = 5) or were negative (n = 3). Interestingly, Clostridium species were additionally detected by 16S rRNA gene NGS in 3 of the 6 subjects with gastrointestinal sources of gram-negative bacteremia and none of the 3 subjects with urinary sources of gram-negative bacteremia. In the 41 remaining subjects, 16S rRNA gene NGS detected at least 1 potentially pathogenic organism in 17. In 15, the detected microorganism clinically correlated with the patient's syndrome. In 17 subjects with a clinically defined infectious syndrome, neither test was positive; in the remaining 7 subjects, a noninfectious cause of clinical presentation was identified. CONCLUSIONS: 16S rRNA gene NGS may be useful for detecting bacteria in plasma of septic patients. In some cases of gram-negative sepsis, it may be possible to pinpoint a gastrointestinal or urinary source of sepsis based on the profile of bacteria detected in plasma.

Diagnostic Value of 16S Ribosomal RNA Gene Polymerase Chain Reaction/Sanger Sequencing in Clinical Practice.

BACKGROUND: Accurate microbiologic diagnosis is important for appropriate management of infectious diseases. Sequencing-based molecular diagnostics are increasingly used for precision diagnosis of infections. However, their clinical utility is unclear. METHODS: We conducted a retrospective analysis of specimens that underwent 16S ribosomal RNA (rRNA) gene polymerase chain reaction (PCR) followed by Sanger sequencing at our institution from April 2017 through March 2019. RESULTS: A total of 566 specimens obtained from 460 patients were studied. Patients were considered clinically infected or noninfected based on final diagnosis and management. In 17% of patients, 16S rRNA PCR/sequencing was positive and in 5% of patients, this test led to an impact on clinical care. In comparison, bacterial cultures were positive in 21% of patients. Specimens with a positive Gram stain had 12 times greater odds of having a positive molecular result than those with a negative Gram stain (95% confidence interval for odds ratio, 5.2-31.4). Overall, PCR positivity was higher in cardiovascular specimens (37%) obtained from clinically infected patients, with bacterial cultures being more likely to be positive for musculoskeletal specimens (P < .001). 16S rRNA PCR/sequencing identified a probable pathogen in 10% culture-negative specimens. CONCLUSION: 16S rRNA PCR/sequencing can play a role in the diagnostic evaluation of patients with culture-negative infections, especially those with cardiovascular infections.

Impact of delayed device re-implantation on outcomes of patients with cardiovascular implantable electronic device related infective endocarditis.

BACKGROUND: Optimal timing of cardiovascular implantable electronic device (CIED) re-implantation following device removal due to infection is undefined. Multinational guidelines reflect this and include no specific recommendation for this timing, while others have recommended waiting at least 14 days in cases of CIED related infective endocarditis (CIED-IE). The current work seeks to clarify this issue. METHODS: We retrospectively reviewed institutional data at Mayo Clinic, Minnesota of patients aged ≥ 18 years who developed CIED-IE from January 1, 1991 to February 1, 2016. CIED-IE was defined as echocardiogram reported device lead or valvular vegetation. Regression analyses were used to relate the risk of clinical outcomes to the interval between CIED removal and re-implantation and the location of vegetations. RESULTS: A total of 109 patients met study inclusion criteria. A majority (68.8%) of patients were men and the median age was 68.0 years. Transoesophageal echocardiogram (TEE) was performed in 95.4% of patients, with valve vegetations detected in 33.9% (n = 37). Survival analysis comparing patients in whom device re-implantation was < 14 days vs. ≥14 days, and further categorized by those with and without valve vegetation, showed a significant difference (P = 0.028); patients with valve vegetation and reimplantation interval < 14 days had the lowest (58.7%) 12-month survival. When adjusted for valve vegetation, longer time interval for reimplantation trended toward increased hospital length of stay (P = 0.079). CONCLUSION: Our findings suggest that the recommended 14-day delay between CIED extraction and re-implantation in CIED-IE patients is associated with a survival benefit, but longer length of hospital stay following re-implantation.

Laryngeal histoplasmosis in a kidney transplant recipient.

Histoplasma capsulatum is an endemic fungus that most oftenly causes a self-limiting illness but can result in severe infections in immunocompromised patients including pulmonary or extra-pulmonary disease. Rarely it can also cause a chronic progressive infection of the larynx. Herein, we report a case of laryngeal histoplasmosis in a kidney transplant patient who presented with progressive symptoms of several weeks of hoarseness, dysphagia and odynophagia. Laryngoscopic examination revealed thick plaques in the oropharynx with surrounding hyper-erythema and histopathology showed numerous intracellular yeasts forms consistent with H capsulatum. Patient was initiated on treatment with itraconazole. Infection of the larynx due to H capsulatum is highly uncommon and therefore can result in an inappropriate or delayed diagnosis. A review of literature showed four previously reported cases of laryngeal histoplasmosis in patients with solid organ transplant. This is the first case series of laryngeal histoplasmosis in transplant recipients.

Clinical Approach to Evaluation of Underlying Cardiac Device Infection in Patients Hospitalized with Bacteremia.

More than 400,000 cardiac implantable electronic devices (CIEDs), including permanent pacemakers, implantable cardioverter-defibrillators, and cardiac resynchronization therapy devices, are implanted every year in the United States (US). Infection is a serious complication of CIED therapy and is associated with high morbidity and mortality. While CIED pocket infection can be diagnosed based on clinical exam findings, positive blood culture may be the only manifestation of CIED lead infection. Thus, management of bacteremia in patients living with CIEDs requires special consideration. This review summarizes contemporary data in the context of the recently updated 2023 Duke-International Society for Cardiovascular Infectious Diseases Criteria for Infective Endocarditis. We have synthesized these data into an algorithmic approach to streamline the diagnostic evaluation of CIED infection in patients presenting with bacteremia.

Chorea as an unusual presenting feature of anti-phospholipid syndrome.

Anti-phospholipid syndrome (APS) can manifest as primary disease or secondary to connective tissue diseases, such as systemic lupus erythematosus (SLE). It is characterized by recurrent arterial or venous thrombosis, thrombocytopenia, haemolytic anaemia, or positive Coombs' test, and recurrent pregnancy loss in females. Common neurological abnormalities include stroke, cognitive deficits and white matter lesions. We present an unusual case of secondary APS associated with SLE, that presented at our clinic with chorea. To the best of our knowledge this is a first such case reported from Pakistan. APS must be ruled out in any patient of SLE who presents with stroke or any other neurological abnormality regardless of the age at presentation. Moreover, unusual neurological presentations, such as chorea, should always be kept in mind in order to promptly diagnose and treat APS owing to its high morbidity and mortality.

Predictors of Bloodstream Infection in Patients Presenting With Cardiovascular Implantable Electronic Device Pocket Infection.

BACKGROUND: Generator pocket infection is the most frequent presentation of cardiovascular implantable electronic device (CIED) infection. We aim to identify predictors of underlying bloodstream infection (BSI) in patients presenting with CIED pocket infection. METHODS: We retrospectively reviewed all adults with CIED pocket infection cared for at our institution from January 2005 through January 2016. The CIED pocket infection cases were then subclassified as with or without associated BSI. Variables with P values <.05 at univariate analysis were included in a multivariable model to identify independent predictors of underlying BSI. RESULTS: We screened 429 cases of CIED infection, and 95 met the inclusion criteria. Of these, 68 cases (71.6%) were categorized as non-BSI and 27 (28.4%) as BSI. There were no statistically significant differences in patient comorbid conditions or device characteristics between the 2 groups. In multivariable analysis, the presence of systemic inflammatory response syndrome criteria (tachycardia, tachypnea, fever or hypothermia, and leukocytosis or leukopenia) and hypotension were independent predictors of underlying BSI in patients presenting with CIED pocket infection. Overall, patients in the non-BSI group who did not receive pre-extraction antibiotics had a higher frequency of positive intraoperative pocket/device cultures than those with pre-extraction antibiotic exposure (79.4% vs 58.6%; P = .06). CONCLUSIONS: Patients with CIED pocket infection who meet systemic inflammatory response syndrome criteria and/or are hypotensive at admission are more likely to have underlying BSI and should be started on empiric antibiotics after blood cultures are obtained. If these features are absent, it may be reasonable to withhold empiric antibiotics to optimize yield of pocket/device cultures during extraction.

Ethical dilemma of recovering organs before donor death.

Organ transplant has had a momentous effect in improving global health over the years. However, there exists a sizeable discrepancy between the supply and demand of organs, especially in developing countries, where lack of expertise, financial constraints, and inadequate transplant facilities have been obstacles. According to current practice, donors must be dead before unpaired vital organs can be recovered. Equal health warrants needs-based health care for everyone. Recovering viable organs from donors while they are alive, but with death inevitable, may be significant to persons on waiting lists. Future policies in organ transplantation must be made after thorough consideration of all aspects of donation and dealing with the inequalities of health care. These pose a challenge for medicolegal and ethical organizations.

Anaplastic large cell lymphoma: the most common T-cell lymphoma in pakistan.

OBJECTIVE: To study the prevalence and immunohistochemical profile of the subtypes of anaplastic large cell lymphomas (ALCLs) at a major referral center of Pakistan. METHODS: Epidemiological data for all mature T-cell non-Hodgkin's lymphoma (NHL) diagnosed between 1st January 2005 and 30th June 2010 at the Aga Khan University Department of Histopathology were reviewed and analyzed with SPSS v17.0. RESULTS: A total of 178 specimens were diagnosed as mature T- and NK- cell NHL during the period. Of these 100 (56.2%) were diagnosed as systemic ALCL. These tumors were of either T- or null-cell type with consistent (100%) expression of CD30 (Ki-1). Forty three (43%) cases were further classified as ALK positive, fifty (50%) as ALK negative and seven (7%) were not tested for ALK expression. The mean age of the ALK positive group was 26.7 years as compared to the ALK negative of 35.6 years. The gender ratio of ALK positive cases was 2.3:1 (M:F) as compared to the 2.5:1 ratio seen in the ALK negative cases. There were no significant differences in the nodal and extra-nodal involvement patterns between ALK+ and ALK- groups but epithelial membrane antigen was positive more often in the ALK positive group. CONCLUSION: Compared to other published studies, this proportion of ALCL within the mature T- and NK- cell lymphoma category was found to be alarmingly high and calls for attention. Further studies should be conducted in our region, which in turn would enable clinicians to successfully battle against this neoplastic disease.

Antimicrobial Photodynamic Therapy with Functionalized Fullerenes: Quantitative Structure-activity Relationships.

Photosensitive dyes or photo sensitizers (PS) in combination with visible light and oxygen produce reactive oxygen species that kill cells in the process known as photodynamic therapy (PDT). Antimicrobial PDT employs PS that is selective for microbial cells and is a new treatment for infections. Most antimicrobial PS is based on tetrapyrrole or phenothiazinium structures that have been synthesized to carry quaternary cationic charges or basic amino groups. However we recently showed that cationic-substituted fullerene derivative were highly effective in killing a broad spectrum of microbial cells after illumination with white light. In the present report we compared a new group of synthetic fullerene derivatives that possessed either basic or quaternary amino groups as antimicrobial PS against Gram-positive (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli) and fungi (Candida albicans). Quantitative structure-function relationships were derived with LogP and hydrophilic lipophilic balance parameters. Compounds with non-quaternary amino groups tended to form nanoaggregates in water and were only effective against S. aureus. The most important determinant of effectiveness was an increased number of quaternary cationic groups that were widely dispersed around the fullerene cage to minimize aggregation. S. aureus was most susceptible; E. coli was intermediate, while C. albicans was the most resistant species tested. The high effectiveness of antimicrobial PDT with quaternized fullerenes suggest they may have applications in treatment of superficial infections (for instance in wounds and burns) where light penetration into tissue is not problematic.