Ten Clinical Pearls in Microbiology: How Effective Collaboration Optimizes Patient Care.

Medical microbiology laboratories play an essential role in patient care - appertaining to infectious diseases diagnostics and treatment, infection prevention, and antimicrobial stewardship. Collaboration between clinicians and the microbiology laboratory can promote and enhance the safety, quality, and efficiency of patient care. We review practical, evidence-informed core concepts to explicate how effective partnership between clinicians and the microbiology laboratory improves patient outcomes.

An unusual case of Brodie's abscess in the humerus of an adult female.

Brodie's abscess is a manifestation of subacute to chronic osteomyelitis, characterized as intraosseous abscess formation, usually on the metaphysis of the long tubular bones in the lower extremities of male pediatric patients. Clinically, Brodie's abscess presents with atraumatic bone pain of an insidious onset, with absence of systemic findings. Delay in diagnosis is common, as diagnostic imaging, followed by biopsy for culture and histologic examination are generally required to secure a diagnosis of Brodie's abscess. Treatment of Brodie's abscess is non-standardized, and usually consists of surgical debridement and antibacterial therapy. Despite the variability in therapeutic approaches, outcomes of Brodie's abscess treated with surgery and antibiotics are favourable. Herein we report a case of a delayed diagnosis of Brodie's abscess in the upper extremity of an adult female. While she improved with treatment of Brodie's abscess, the case serves to remind clinicians to consider this entity in adult individuals who present with atraumatic bone pain.

The addition of mammalian cell culture medium impacts nanoparticle toxicity in zebrafish.

Engineered nanomaterials (ENMs) are ubiquitous in contemporary applications, yet their environmental and human health impacts remain inadequately understood. This study addresses the challenge of identifying potential risks associated with ENM exposure by highlighting the significant variability in existing research methodologies. Without a systematic collection of toxicological data that encompasses standardized materials, relevant platforms, and assays, the task of identifying potential risks linked to ENM exposure becomes an intricate challenge. In vitro assessments often use media rich in ionic species, such as RPMI and fetal bovine serum (FBS). Zebrafish embryos, known to develop normally in low-ionic environments, were exposed to Cerium Oxide, Zinc Oxide, and Graphene Oxides in different media at varying concentrations. Here, we discovered that zebrafish embryos tolerated a mix of 80 % RPMI, 2 % FBS, and 1 % antibiotic cocktail. The results revealed that adverse effects observed in zebrafish with certain nanomaterials in Ultra-Pure (UP) water were mitigated in cell culture medium, emphasizing the importance of revisiting previously considered non-toxic materials in vitro. The zebrafish results underscore the importance of utilizing a multidimensional in vivo platform to gauge the biological activity of nanomaterials accurately.

Polymerase chain reaction negative cryptococcal meningitis.

A 61-year-old male with subacute headache was found to have cryptococcal meningitis despite a negative BioFire FilmArray meningitis/encephalitis panel. This case underscores the importance of liberal cryptococcal antigen testing, and that a negative FilmArray panel is inadequate in excluding cryptococcal meningitis, particularly in a HIV-negative host.

Recurrent amebic liver abscesses despite metronidazole treatment: A rare case report.

Amebic liver abscesses should be considered in adult males with a liver abscess and a history of travel to endemic areas. Effective treatment includes metronidazole, followed by paromomycin.

Ten common misconceptions about antibiotic use in the hospital.

Antimicrobials are one of the most administered medications in hospitals. Thoughtful and rational antibiotic prescribing by clinicians are important in reducing the adverse effects to both the host that takes the antibiotic and also the individuals in the host's community. Principles informing antibiotic prescribing in the hospital are commonly rooted in misconceptions. We review 10 common myths associated with antibacterial usage in hospitalized patients and share contemporary evidence in hopes of enhancing evidence-informed practice in this patient care setting.

Management of Pyogenic Liver Abscesses: Contemporary Strategies and Challenges.

Pyogenic liver abscesses (PLAs) are a suppurative infection of the hepatic parenchyma responsible for significant morbidity and mortality. PLAs are categorized into a variety of mechanisms: (1) via the portal vein, (2) through the biliary tract, (3) via the hepatic artery, (4) from trauma, (5) contiguously via direct extension, and (6) cryptogenically. The pathogenesis of PLA, which informs treatment, can often be discerned based on host factors, clinical presentation, and causative microorganisms. The Streptococcus anginosus group, hypervirulent Klebsiella pneumoniae , and multidrug-resistant gram-negative pathogens have emerged as microbiologically challenging organisms to treat. The identification of hypervirulent K. pneumoniae should prompt for assessment for metastatic spread and consideration of prolonged antimicrobial treatment. Abdominal imaging is indispensable in characterizing PLAs and facilitating source control interventions. Source control remains the most critical aspect of PLA management, followed by antimicrobial therapy. Empiric antibiotics for PLAs are informed by the suspected etiology of PLA formation. Duration of antimicrobial therapy is individualized and dependent on multiple components, including the success of achieving source control, host factors, mechanism of PLA development, and the illness course of the individual-factoring in clinical, biochemical, and radiographic parameters.

Incidence, susceptibility and outcomes of candidemia in adults living in Calgary, Alberta, Canada (2010-2018).

BACKGROUND: Candidemia is increasing in frequency and is associated with high mortality. We sought to determine the burden of illness, the population it affects and its resistance profile in our region. METHODS: The Calgary Zone (CZ) provides all care for residents of Calgary and surrounding communities (~ 1.69 million) via five tertiary hospitals each served by a common single laboratory for acute care microbiology. All adult patients in the CZ with at least one Candida spp.-positive blood culture between January 1, 2010, and December 31, 2018, were identified using microbiological data from Calgary Lab Services, the laboratory that processes > 95% of all blood culture samples in the CZ, were reviewed for the study. RESULTS: The overall annual incidence of candidemia among individuals living in the CZ was 3.8 per 100,000 persons (Median age 61 years (IQR 48-72) and 221/455 (47.4%) were female). C. albicans was the most common species (50.6%), followed by C. glabrata, (24.0%). No other species accounted for more than 7% of cases. Overall mortality at 30, 90, and 365 days was 32.2, 40.1, and 48.1% respectively. Mortality rate did not differ by Candida species. Of individuals who developed candidemia, more than 50% died within the next year. No new resistance pattern has emerged in the most common Candida species in Calgary, Alberta. CONCLUSIONS: In Calgary, Alberta, the incidence of candidemia has not increased in the last decade. C. albicans was the most common species and it remains susceptible to fluconazole.

How I manage bacterial prostatitis.

BACKGROUND: Bacterial prostatitis is a highly prevalent infection responsible for significant morbidity among men. The diagnosis and treatment for bacterial prostatitis remains complicated. The difficulty in diagnosis is in part owing to the paucity of high-quality evidence that guides a clinician's interpretation of patients' history, physical examination, and laboratory findings. Treatment is challenging because of the few antimicrobials capable of prostate penetration, growing antimicrobial resistance limiting effective treatment options, and the high risk of recurrence. OBJECTIVES: We aimed to provide a useful resource for clinicians in effectively diagnosing and managing acute bacterial prostatitis (ABP) and chronic bacterial prostatitis (CBP). SOURCES: A PubMed literature search on prostatitis was performed with no restrictions on publication date. CONTENT: The epidemiology, pathophysiology, diagnosis, and treatment for ABP and CBP are explored using a clinical vignette as relevant context. IMPLICATIONS: Bacterial prostatitis can be diagnosed through a focused history and microbiological investigations. The Meares-Stamey 4-glass test or modified 2-glass test can help confirm the diagnosis if uncertainty exists. Typical uropathogens are common contributors to bacterial prostatitis but there is growing interest in exploring the role atypical and traditional non-pathogenic organisms may have. Fluoroquinolones remain first-line therapy, followed by trimethoprim-sulfamethoxazole (TMP-SMX) or doxycycline if the pathogen is susceptible. Fosfomycin has emerged as a repurposed and useful agent because of the increasing incidence of multidrug-resistant pathogens. Selection of appropriate antimicrobial regimens can be challenging and is dependent on the host, chronicity of symptoms, uropathogens' susceptibilities, antimicrobials' side effect profile, and the presence of prostatic abscesses or calcifications. ABP can typically be treated similar to other complicated urinary tract infections. However, CBP requires prolonged therapy, with a minimum of 4 weeks and up to 12 weeks of therapy.

The Golden Grapes of Wrath - Staphylococcus aureus Bacteremia: A Clinical Review.

Staphylococcus aureus bacteremia is common and associated with fatality rates approximating 25%. We provide a brief overview of S. aureus bacteremia from a clinical and microbiological lens and review the relevant evidence and literature gaps in its management. Using a case-based approach, evidence and clinical judgement are meshed to highlight and justify the 5 core interventions that ought to be performed for all cases of S. aureus bacteremia: 1) appropriate anti-staphylococcal therapy, 2) screening echocardiography, 3) assessment for metastatic phenomena and source control, 4) decision on duration of antimicrobial therapy, and 5) Infectious Diseases consultation.

Disseminated nocardiosis in an immunocompetent host with occupational exposure.

Nocardia is a genus of Gram-positive, partially acid-fast bacteria consisting of over 120 species, of which 50 are recognized as human pathogens. Nocardia spp. are common colonizers in the environment, particularly in soil and water. Nocardia spp. typically cause opportunistic infections in the immunocompetent host, although cases of nocardiosis have been described in those with a normal immune system. Nocardiosis can be localized, most often in the skin or lung, or be disseminated, with involvement of the brain, bone, and visceral organs. Treatment of nocardiosis is complex, as multiple culture-directed antibacterials with appropriate tissue penetration may need to be used for a prolonged duration. To our knowledge, we describe the first successfully treated case of disseminated Nocardia beijingensis infection in an immunocompetent host with doxycycline and trimethoprim-sulfamethoxazole and hypothesize that his occupational exposure to ubiquitous saprophytes may have led to his infection.

Burkitt Lymphoma of the Appendix Presenting With Acute Appendicitis and Acute Kidney Injury: A Case Report and Review of Literature.

The gastrointestinal tract is one of the most common sites for extranodal Burkitt lymphomas (BLs), but an appendiceal BL is extremely rare. We describe a case of appendiceal BL presenting with acute appendicitis and acute kidney injury. A 15-year-old obese male presented to the emergency department with fever and right-sided abdominal pain. WBC count was slightly increased, and a CT scan of the abdomen showed features of ruptured appendicitis and peritonitis. The patient was placed on antibiotics, and an interval appendectomy was planned. The patient developed a worsening acute kidney injury one day later, requiring a laparoscopic appendectomy. Gross examination of the appendix revealed a dilated, firm, sausage-like appendix with a hemorrhagic serosa and a firm mesoappendix. Microscopic examination of the appendix showed a dense diffuse infiltration of monomorphic medium-sized atypical lymphoid cells with round nuclei, dispersed chromatin, and small nucleoli. Few scattered macrophages created a vague "starry sky" appearance. Many mitotic figures were seen. The lesion also involved the mesoappendix. Immunohistochemical analysis showed that the lymphoma expressed CD10, CD20, and BCL6 but was negative for CD34, BCL2, and TdT. Later, the fluorescence in situ hybridization (FISH) analysis detected an IGH-MYC (8;14) fusion. A final diagnosis of appendicular Burkitt lymphoma was made. Two weeks later, a bone marrow biopsy performed for staging showed involvement of bone marrow by BL. The patient lost follow-up after that due to the transfer of care to another hospital.

Principles of empiric antimicrobial usage and dosing: Lessons learned.

A lack of clinical response to empiric antimicrobials behooves the clinician to reflect further on diagnostic considerations. When prescribing antibiotics, determining the correct dose, most optimal route of administration, and considering the pharmacokinetic properties of the drug with respect to clinical and patient factors are crucial.

Epidemiology and risk factors for pyogenic liver abscess in the Calgary Health Zone revisited: a population-based study.

BACKGROUND: Pyogenic liver abscess (PLA), although uncommon in North America, is associated with significant morbidity and mortality. We sought to re-examine the epidemiology, risk factors, and outcomes of PLA in a large, diverse Canadian health zone. METHODS: All Calgary Health Zone (CHZ) residents aged ≥20 with PLA between 2015 and 2017 were identified. Incidence and mortality rates were calculated using census data. Risk factors for PLA were identified using a multivariate analysis. Data was compared to 1999-2003 data, also collected in the CHZ. RESULTS: There were 136 patients diagnosed with PLA between 2015 and 2017. Incidence rate during this period increased significantly relative to 1999-2003 (3.7 vs 2.3 cases/100,000 population, p < 0.01), however, mortality rates remained similar. The microbiological composition of PLA did not change over this 15-year time period but the number of antimicrobial resistant isolates did increase (8% vs 1%, p = 0.04). The greatest risk factors for PLA relative to general populations included current malignancy, liver-transplant, end-stage renal disease, and cirrhosis. Thirty-day mortality was 7.4% and independent risk factors included polymicrobial bacteremia, absence of abscess drainage, congestive-heart failure, a history of liver disease, and admission bilirubin. CONCLUSIONS: Pyogenic liver abscess is a health concern with rising incidence rate. The increasing prevalence of comorbidities in our population and factors that are associated with risk of PLA suggests this will continue to be an emerging diagnosis of concern. Increasing prevalence of antibiotic resistant organisms compounding unclear optimal treatment regimens is an issue that requires urgent study.

Forgoing transesophageal echocardiogram in selected patients with complicated Staphylococcus aureus bacteremia.

Infective endocarditis (IE) has been increasingly recognized as an important complication of Staphylococcus aureus bacteremia (SAB), leading to a low threshold for echocardiography and extended treatment with anti-staphylococcal agents. However, outside of IE, many indications for prolonged anti-staphylococcal therapy courses are present. We sought to determine the frequency in which findings from a transesophageal echocardiogram (TEE) changed clinical SAB management in a large Canadian health region. Residents (> 18 years) with SAB from 2012 to 2014 who underwent transthoracic echocardiogram (TTE) and TEE were assessed. Patients potentially benefiting from an extended course of anti-staphylococcal agents were defined a priori. Patient demographics, treatment (including surgical), and clinical outcomes were extracted and evaluated. Of the 705 episodes of SAB that underwent a screening echocardiogram, 203 episodes underwent both a TTE and TEE, of which 92.1% (187/203) contained an a priori indication for extended anti-staphylococcal therapy. Regardless of TEE results, actual duration of therapy did not differ in SAB episodes that had ≥ 1 extended anti-staphylococcal therapy criteria (36.7 days, IQR 23.4-48.6 vs. 43.8 days, IQR 33.3-49.5, p = 0.17). Additionally, there were no cases in which TEE was utilized as the sole reason to shorten duration of therapy or proceed to surgery for those with SAB. Routine performance of TEE may be unnecessary in all SAB as many patients have pre-existing indications for extended anti-staphylococcal therapy independent of TEE findings. An algorithm to selectively identify cases of SAB that would benefit from TEE can reduce resource and equipment expenditure and patient risks associated with TEE.