An inconspicuous identification: Isolation and identification of a novel Pichia species presenting as fungemia following cardiac surgery.

Fungemia is common in critically ill patient populations, and is associated with a high rate of mortality, especially when caused by nonalbicans Candida species. Herein, we describe a fatal case of fungemia following cardiothoracic surgery in which the organism, initially identified as Candida inconspicua, represents a novel species: Pichia alaskaensis.

Outcomes of transplant recipients with pretransplant Nocardia colonization or infection.

BACKGROUND: Specific pretransplant infections have been associated with poor posttransplant outcomes. However, the impact of pretransplant Nocardia isolation has not been studied. METHODS: We performed a retrospective study from three centers in Arizona, Florida, and Minnesota of patients with Nocardia infection or colonization who subsequently underwent solid organ or hematopoietic stem cell transplantation from November 2011 through April 2022. Outcomes included posttransplant Nocardia infection and mortality. RESULTS: Nine patients with pretransplant Nocardia were included. Two patients were deemed colonized with Nocardia, and the remaining seven had nocardiosis. These patients underwent bilateral lung (N = 5), heart (N = 1), heart-kidney (N = 1), liver-kidney (N = 1), and allogeneic stem cell transplantation (N = 1) at a median of 283 (interquartile range [IQR] 152-283) days after Nocardia isolation. Two (22.2%) patients had disseminated infection, and two were receiving active Nocardia treatment at the time of transplantation. One Nocardia isolate was resistant to trimethoprim-sulfamethoxazole (TMP-SMX) and all patients received TMP-SMX prophylaxis posttransplant, often for extended durations. No patients developed posttransplant nocardiosis during a median follow-up of 1.96 (IQR 0.90-6.33) years. Two patients died during follow-up, both without evidence of nocardiosis. CONCLUSIONS: This study did not identify any episodes of posttransplant nocardiosis among nine patients with pretransplant Nocardia isolation. As patients with the most severe infections may have been denied transplantation, further studies with larger sample sizes are needed to better analyze any impact of pretransplant Nocardia on posttransplant outcomes. However, among patients who receive posttransplant TMP-SMX prophylaxis, these data suggest pretransplant Nocardia isolation may not impart a heightened risk of posttransplant nocardiosis.

Emergence of Inducible Macrolide Resistance in Mycobacterium chelonae Due to Broad-Host-Range Plasmid and Chromosomal Variants of the Novel 23S rRNA Methylase Gene, erm(55).

Macrolides are a mainstay of therapy for infections due to nontuberculous mycobacteria (NTM). Among rapidly growing mycobacteria (RGM), inducible macrolide resistance is associated with four chromosomal 23S rRNA methylase (erm) genes. Beginning in 2018, we detected high-level inducible clarithromycin resistance (MICs of ≥16µg/mL) in clinical isolates of Mycobacterium chelonae, an RGM species not previously known to contain erm genes. Using whole-genome sequencing, we identified a novel plasmid-mediated erm gene. This gene, designated erm(55)P, exhibits <65% amino acid identity to previously described RGM erm genes. Two additional chromosomal erm(55) alleles, with sequence identities of 81% to 86% to erm(55)P, were also identified and designated erm(55)C and erm(55)T. The erm(55)T is part of a transposon. The erm(55)P allele variant is located on a putative 137-kb conjugative plasmid, pMchErm55. Evaluation of 133 consecutive isolates from 2020 to 2022 revealed 5 (3.8%) with erm(55). The erm(55)P gene was also identified in public data sets of two emerging pathogenic pigmented RGM species: Mycobacterium iranicum and Mycobacterium obuense, dating back to 2008. In both species, the gene appeared to be present on plasmids homologous to pMchErm55. Plasmid-mediated macrolide resistance, not described previously for any NTM species, appears to have spread to multiple RGM species. This has important implications for antimicrobial susceptibility guidelines and treatment of RGM infections. Further spread could present serious consequences for treatment of other macrolide-susceptible RGM. Additional studies are needed to determine the transmissibility of pMchErm55 and the distribution of erm(55) among other RGM species.

Clinical manifestations, treatment and outcomes of patients infected with Mycobacterium haemophilum with a focus on immune reconstitution inflammatory syndrome: a retrospective multi-site study.

BACKGROUND: Mycobacterium haemophilum is a nontuberculous mycobacterium with fastidious in vitro growth requirements and an increasingly reported cause of extrapulmonary disease. Timely diagnosis and management of M. haemophilum infections and the immune reconstitution inflammatory syndromes (IRIS) observed in a subset of patients during treatment remain challenging. METHODS: We conducted a retrospective chart review between January 1, 2010, and January 1, 2022 and identified 26 patients diagnosed with M. haemophilum infection at our institution. We describe their clinical presentation, diagnostic results, management, and outcomes. RESULTS: The majority of patients in our cohort had upper and/or lower extremity skin involvement, were immunosuppressed, and had generally favourable treatment outcomes. All tested M. haemophilum isolates were susceptible in vitro to clarithromycin and trimethoprim-sulfamethoxazole. Moreover, high rates of susceptibility were noted for ciprofloxacin (95%), linezolid (90%), and rifampin (85%). IRIS was identified in 31% of cases and should be considered in patients who develop worsening skin lesions or systemic symptoms following the initiation of effective antimicrobial therapy. Visualisation of acid-fast bacilli on initial tissue stains, a positive mycobacterial blood culture, and rapid de-escalation of tumour necrosis factor-α inhibitors and/or corticosteroids were more frequently encountered among patients in our cohort who developed IRIS. CONCLUSION: M. haemophilum infection should be considered among patients receiving immunomodulatory therapy who develop discoloured or nodular skin lesions involving the extremities, worsening focal arthritis, tenosynovitis, or isolated adenopathy. A heightened awareness of this pathogen's clinical and laboratory characteristics can lead to a timely diagnosis and favourable outcome.

Fungal Diagnostic Stewardship in Bronchoscopy Specimens for Immunocompetent Patients in the Intensive Care Unit.

OBJECTIVE: To evaluate the diagnostic yield of fungal smears and cultures from bronchial lavage and wash specimens obtained from immunocompetent patients in the intensive care unit (ICU) because respiratory tract samples from patients in the ICU often undergo extensive microbiological testing. PATIENTS AND METHODS: In total, we enrolled 112 immunocompetent adult patients treated in the medical and surgical ICU between July 1, 2016, and June 30, 2017. We evaluated whether the results of fungal smears and cultures of specimens obtained from bronchoscopy and bronchoalveolar lavage changed patient care. RESULTS: In total, 131 bronchoscopic specimens and 31 bronchoalveolar lavage specimens were tested for fungi. Cultures were held for an estimated 4680 culture-days. Two results changed patient therapy. In both cases, other routine tests provided the same information as fungal culture before these results were returned. CONCLUSION: In immunocompetent, critically ill patients, fungal culture of respiratory tract specimens does not add diagnostic value. Routine fungal culture of respiratory tract specimens should be discouraged in this population.

Eumycetoma caused by Cladophialophora bantiana in the United States.

A female presented in the sixth decade of life with a history of undifferentiated small cell carcinoma of the right breast in clinical remission, status-post chemotherapy and resection 6 years previously, presented with a chronic anterior knee skin nodule that grew in size over the prior 5-6 weeks. She had no history of opportunistic infections or recent immunosuppression. As it grew, the nodule became tender to touch. Examination revealed a 4-6 mm superficial purple-red nodule. Also, a similar lesion was present on the dorsum of her left foot for the past year, which also recently grew and became tender. The patient did report frequently kneeling on soil when gardening in Florida. She reported no other symptoms. Due to a concern for cutaneous metastasis of the patient's previously diagnosed small cell carcinoma of the breast, the anterior knee lesion was biopsied. Histology revealed histocyte-rich inflammation with foci of acute inflammation as well as pigmented fungal forms. Subsequent fungal culture of excised tissue grew Cladophialophora bantiana, identified by ribosomal gene DNA sequencing.

A rare case of chronic otitis externa due to Mycobacterium tuberculosis.

Chronic otitis externa due to Mycobacterium tuberculosis complex is extremely rare and very few cases have been presented in the medical literature. We report here the case of an immunocompetent 68-year-old male with chronic auricular drainage, otalgia, hearing loss, external ear canal and tympanic membrane thickening for 3 years who was ultimately diagnosed with tuberculous chronic otitis externa on biopsy of external auditory canal granulation tissue using molecular diagnostic techniques. Later, sputum cultures were positive for Mycobacterium tuberculosis complex indicating disseminated tuberculosis. However, two plausible explanations could be pulmonary TB that disseminated to the ear canal with evidence of middle and outer otitis, or upper airway/nasopharyngeal involvement with direct extension into the middle and outer ear canals. Although extremely rare, extrapulmonary laryngeal head and neck tuberculosis should be considered in immunocompetent patients who present with chronic otitis without prior known exposure to tuberculosis when they fail standard therapy and in whom no other microbiologic cause can be identified.

Disseminated Mycobacterium chimaera Infection After Cardiothoracic Surgery.

Ten case reports of disseminated Mycobacterium chimaera infections associated with cardiovascular surgery were published from Europe. We report 3 cases of disseminated M chimaera infections with histories of aortic graft and/or valvular surgery within the United States. Two of 3 patients demonstrated ocular involvement, a potentially important clinical finding.

A cluster of Mycobacterium wolinskyi surgical site infections at an academic medical center.

OBJECTIVE: To study a cluster of Mycobacterium wolinskyi surgical site infections (SSIs). DESIGN: Observational and case-control study. SETTING: Academic hospital. PATIENTS: Subjects who developed SSIs with M. wolinskyi following cardiothoracic surgery. METHODS: Electronic surveillance was performed for case finding as well as electronic medical record review of infected cases. Surgical procedures were observed. Medical chart review was conducted to identify risk factors. A case-control study was performed to identify risk factors for infection; Fisher exact or Kruskal-Wallis tests were used for comparisons of proportions and medians, respectively. Patient isolates were studied using pulsed-field gel electrophoresis (PFGE). Environmental microbiologic sampling was performed in operating rooms, including high-volume water sampling. RESULTS: Six definite cases of M. wolinskyi SSI following cardiothoracic surgery were identified during the outbreak period (October 1, 2008-September 30, 2011). Having cardiac surgery in operating room A was significantly associated with infection (odds ratio, 40; P = .0027). Observational investigation revealed a cold-air blaster exclusive to operating room A as well a microbially contaminated, self-contained water source used in heart-lung machines. The isolates were indistinguishable or closely related by PFGE. No environmental samples were positive for M. wolinskyi. CONCLUSIONS: No single point source was established, but 2 potential sources, including a cold-air blaster and a microbially contaminated, self-contained water system used in heart-lung machines for cardiothoracic operations, were identified. Both of these potential sources were removed, and subsequent active surveillance did not reveal any further cases of M. wolinskyi SSI.

Mycobacterium arupense flexor tenosynovitis: case report and review of antimicrobial susceptibility profiles for 40 clinical isolates.

We describe a case of chronic tenosynovitis in the hand of a 58-year-old cattle farmer. Surgical biopsy specimens grew Mycobacterium arupense. The patient responded to surgery and antimicrobial therapy based on in vitro susceptibility testing. The antimicrobial susceptibility profiles of the isolate from this patient and 39 additional clinical isolates are presented.

Misidentification of Neosartorya pseudofischeri as Aspergillus fumigatus in a lung transplant patient.

We present a case of disseminated Neosartorya pseudofischeri infection in a bilateral lung transplant patient with cystic fibrosis. The organism was originally misidentified from respiratory specimens as Aspergillus fumigatus using colonial and microscopic morphology. DNA sequencing subsequently identified the organism correctly as N. pseudofischeri.

Pulmonary necrotizing granulomas of unknown cause: clinical and pathologic analysis of 131 patients with completely resected nodules.

BACKGROUND: The cause of pulmonary necrotizing granulomas is often unclear, even after histologic examination. Our aim was to determine the clinical significance of histologically unexplained necrotizing granulomas. METHODS: Pulmonary necrotizing granulomas surgically resected at the Mayo Clinic (1994-2004) were retrieved and reviewed retrospectively. Cases in which a cause was evident at the time of initial histologic examination were excluded. The analysis cohort comprised 131 completely resected histologically unexplained pulmonary necrotizing granulomas. Clinical and laboratory information was abstracted from medical records, chest CT scans were reviewed, histologic slides were reexamined, and additional ancillary studies were performed in selected cases. RESULTS: A cause was determined on review in more than one-half of the histologically unexplained necrotizing granulomas (79 of 131, 60%) by reexamining histologic slides (47), incorporating the results of cultures (26), fungal serologies (14), and other laboratory studies (eight), and correlating histologic findings with clinical and radiologic information (13). Infections accounted for the majority (64 of 79), the most common being histoplasmosis (37) and nontuberculous mycobacterial infections (18). Noninfectious diagnoses (15 of 79) were rheumatoid nodule (five), granulomatosis with polyangiitis (Wegener) (five), sarcoidosis (four), and chronic granulomatous disease (one). Many cases remained unexplained even after extensive review (52 of 131, 40%). Most of these patients received no medical therapy and did not progress clinically or develop new nodules (median follow-up, 84 months). CONCLUSIONS: A cause, the most common being infection, can be established in many surgically resected pulmonary necrotizing granulomas that appear unexplained at the time of initial histologic diagnosis. Patients whose granulomas remain unexplained after a rigorous review have a favorable outcome. Most do not develop new nodules or progress clinically, even without medical therapy.

Detection of (1, 3)-ß-D-glucan in bronchoalveolar lavage and serum samples collected from immunocompromised hosts.

The incidence of invasive fungal infections (IFI) has increased in recent years, especially among immunocompromised hosts (ICH). In 2003, the Fungitell(®) assay received FDA clearance for the presumptive diagnosis of IFI using serum and detects (1-3)-ß-D-glucan, which is a major cell wall component of certain fungi (e.g., Candida, Aspergillus, and Pneumocystis). The goal of the current study was to assess the performance of the assay on bronchoalveolar lavage (BAL) fluid and serum to identify IFI in ICH. Patients were classified as having proven, probable, possible, or no IFI according to the European Organization for Research and Treatment of Cancer/Mycoses Study Group (EORTC/MSG) guidelines. Among 109 patients for whom the results of Fungitell were compared to the EORTC/MSG criteria, Fungitell showed a low positive predictive value for the identification of IFI from both BAL (20.0%) and serum (26.7%). However, the negative predictive value of Fungitell was significantly higher for both sample types (BAL, 83.0%; serum, 84.8%). Interestingly, the results of Fungitell were positive in BAL and serum in 7/8 (87.5%) patients diagnosed with Pneumocystis pneumonia (PcP) by real-time, non-nested PCR. These data indicate that the Fungitell assay has a low positive predictive value for the diagnosis of IFI in ICH, regardless of the specimen type that is tested. However, testing of serum samples by Fungitell may permit a rapid and noninvasive initial screening approach in patients with presumed PcP.

A multicenter evaluation of tests for diagnosis of histoplasmosis.

BACKGROUND: The sensitivity of the MVista Histoplasma antigen enzyme immunoassay (MiraVista Diagnostics) has been evaluated in disseminated histoplasmosis in patients with AIDS and in the "epidemic" form of acute pneumonia. Moreover, there has been no evaluation of the sensitivity of antigenemia detection in disseminated histoplasmosis after the implementation of methods to dissociate immune complexes and denature released antibodies. The goal of this study was to determine the sensitivity of the current antigen assay in different categories of histoplasmosis. METHODS: Urine and serum specimens obtained from 218 patients with histoplasmosis and 229 control subjects, including 30 with blastomycosis, were tested. RESULTS: Antigenuria was detected in 91.8% of 158 patients with disseminated histoplasmosis, 83.3% of 6 patients with acute histoplasmosis, 30.4% of 46 patients with subacute histoplasmosis, and 87.5% of 8 patients with chronic pulmonary histoplasmosis; antigenemia was present in 100% of 31 tested cases of disseminated histoplasmosis. Among patients with disseminated cases, antigenuria was detected more often and at higher concentrations in immunocompromised patients and those with severe disease. Specificity was 99.0% for patients with nonfungal infections (n = 130) and in healthy subjects (n = 69), but cross-reactivity occurred in 90% of patients with blastomycosis. CONCLUSIONS: The sensitivity of antigen detection in disseminated histoplasmosis is higher in immunocompromised patients than in immunocompetent patients and in patients with more severe illness. The sensitivity for detection of antigenemia is similar to that for antigenuria in disseminated infection.

Preemployment screening for tuberculosis in a large health care setting: comparison of the tuberculin skin test and a whole-blood interferon-γ release assay.

OBJECTIVE: Determine the performance of an interferon-γ release assay in a health care occupational surveillance program. METHODS: From January 11, 2005, through January 31, 2006, all new employees (n = 652) undergoing standard, preemployment evaluation at Mayo Clinic, Rochester, Minnesota were evaluated for tuberculosis using a standard process of symptom screening combined with tuberculin skin test (TST) and QuantiFERON-TB Gold test (QFT-G). RESULTS: Comparing the results of QFT-G directly to TST, QFT-G showed an overall agreement of 92.5%. CONCLUSIONS: False-positive TST were the most significant issue affecting agreement, and in a low-tuberculosis prevalence population, the need for an effective strategy offering low false-positive results may be best met by combining the TST with QFT-G.

Evaluation of three commercial latex agglutination kits and a commercial enzyme immunoassay for the detection of cryptococcal antigen.

We compared the performance of the Meridian CALAS, Wampole Crypto-LA, Murex Cryptococcus latex agglutination assay, and the Meridian Premier EIA for the detection of cryptococcal antigen in serum and CSF. The assays demonstrated similar performance characteristics based on concordance values > or = 93% but important differences were noted in endpoint titers.

Deactivation of the dimorphic fungi Histoplasma capsulatum, Blastomyces dermatitidis and Coccidioides immitis using hydrogen peroxide vapor.

Hydrogen peroxide vapour (HPV) has been proposed as an alternative to formaldehyde fumigation for the decontamination of biosafety level (BSL) III laboratories. The aim of this study was to evaluate the efficacy of HPV against the dimorphic fungi Histoplasma capsulatum, Blastomyces dermatitidis and Coccidioides immitis. Working inside a class II biological safety cabinet (BSC) within a BSL III laboratory, inocula containing approximately 5-log(10) cfu/ml from the mould form of each organism suspended in RPMI medium were deposited on stainless steel discs and allowed to air dry. The organisms were exposed to HPV inside a BSC using a BIOQUELL ClarusS HPV generator. In three replicate experiments, individual discs were transferred into liquid media at timed intervals during a 105 minute HPV exposure period. Control- and HPV-exposed discs were incubated in RPMI media at 30 degrees C for 6 weeks to determine if any viable organisms remained. Positive cultures were confirmed using specific nucleic acid hybridization probes. Results indicate that H. capsulatum, B. dermatitidis and C. immitis were killed within 30 minutes of HPV exposure.

Use of hydrogen peroxide vapor for deactivation of Mycobacterium tuberculosis in a biological safety cabinet and a room.

Mycobacterium tuberculosis is an important human pathogen that is routinely cultured in clinical and research laboratories. M. tuberculosis can contaminate surfaces and is highly resistant to disinfection. We investigated whether hydrogen peroxide vapor (HPV) is effective for the deactivation of M. tuberculosis on experimentally contaminated surfaces in a biological safety cabinet (BSC) and a room. Biological indicators (BIs) consisting of an approximately 3-log(10) inoculum of M. tuberculosis on stainless steel discs and a 6-log(10) inoculum of Geobacillus stearothermophilus were exposed to HPV in BSC time course experiments and at 10 locations during room experiments. In three separate BSC experiments, M. tuberculosis BIs were transferred to growth media at 15-min intervals during a 180-min HPV exposure period. No M. tuberculosis BIs grew following 30 min of HPV exposure. In three separate room experiments, M. tuberculosis and G. stearothermophilus BIs were exposed to HPV for 90, 120, and 150 min, respectively. BIs for both microorganisms were deactivated in all 10 locations following 90 min of HPV exposure. HPV provides an alternative to traditional decontamination methods, such as formaldehyde fumigation, for laboratories and other areas contaminated with M. tuberculosis.