Rebecca Yee

Objectives: Helicobacter pylori infections result in significant global disease burden related to chronic gastritis, peptic ulcer disease, and gastric cancer. Optimal treatment requires knowledge of local resistance epidemiology. We characterized our patient population infected with H pylori in Washington, DC, United States, and evaluated the diagnostic utility of microbiology and surgical pathology approaches for H pylori diagnosis. Methods: A retrospective, observational study was performed from April 2015 to March 2022, consisting of patients positive for H pylori. Review of the electronic medical record for patient demographics, clinical presentation, laboratory results, and clinical management was performed. Results: Top clinical presentations in our patients with H pylori infections (n = 31, mean age 51 years) were abdominal pain (55%), gastroesophageal reflux disease (19%), and nausea/vomiting (10%), with most (84%) experiencing recurrent disease. Concordant findings (n = 105 specimens) between microbiology and surgical pathology were noted in 96% of patients. Microbiology testing provided a faster preliminary positive diagnosis by 3 days (P < .00001). For both approaches, antrum biopsy specimens demonstrated a 100% recovery rate (odds ratio [OR], 5.4). Active gastritis was the most common diagnosis (82%), which significantly increased the likelihood of H pylori seen in microbiology smears (OR, 1.7) and viable recovery of the organism (OR, 2.6) for further antimicrobial susceptibility testing. Our antibiogram revealed more than 55% resistance to first-line drugs, with 77% of our isolates being multidrug resistant. Conclusions: An accurate diagnosis of an H pylori infection is dependent on specimen site and disease severity. Appropriate biopsy collection and ordering of microbiology and surgical pathology tests maximize diagnostic utility. A local antibiogram is essential for guiding empiric therapy.

Gastroenteritis is commonly caused by viral etiologies. The inclusion of astrovirus on multiplex, syndromic gastrointestinal PCR panels allows for the detection and characterization of infected patients. This retrospective, observational, clinical study examines the epidemiology and clinical characteristics of astrovirus infections in adults from our institution in Washington D.C. (USA) over a seven-year period. Chart abstraction was performed to collect patient demographics, laboratory results, clinical presentation, and management. The overall positivity rate of astrovirus was 0.6%. Peak seasons were late winter to spring (February–April). The mean age was 32 years old (range: 18–52 years). All patients presented with gastroenteritis symptoms and were immunocompetent except one. Symptoms varied among diarrhea, abdominal pain, vomiting, and fever, but patients in age group 30–39 years experienced less vomiting (p = 0.01). Infected patients had an increase in monocytes and neutrophils and a decrease in lymphocytes (p < 0.001). Gastrointestinal co-infections were seen in 24% of our patients. In all patients, clinicians acknowledged the detection of astrovirus and discharged patients without further treatment. The median length of stay was 6 h, and no patients were admitted into the intensive care unit. We show that astrovirus infections in immunocompetent adults were associated with mild disease associated with specific cell counts and different symptoms correlated with age.

Identification of mycobacterial infections for both Mycobacterium tuberculosis and non-tuberculosis mycobacteria is important for effective patient care. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a promising tool that is used in many clinical laboratories for the identification of bacteria and yeast. This study evaluates the impact of growth media on the performance of the MALDI Biotyper^® MBT smart MS for mycobacteria identification. Increased rates of identification, particularly in non-rapid growers and pigment producers, and higher confidence scores were generated in mycobacteria isolated from solid agar, rather than liquid broth. Testing each isolate in triplicate can increase yield of detection. Using the Bruker MBT Mycobacteria Kit to process our samples for testing on the Bruker MALDI Biotyper^® instrument generated precise and accurate mycobacteria identification. These findings emphasize the importance of optimizing mycobacterial specimen processing workflows to include appropriate culture media, which can enhance mycobacterial identification and improve diagnostic accuracy.

HHV-8 infection can be asymptomatic in immunocompetent individuals but poses significant risks in immunocompromised patients. As an oncovirus, it can lead to Kaposi sarcoma (KS), primary effusion lymphoma, and multicentric Castleman disease (MCD). While the association between HHV-8 and HIV is well-established, other co-infections remain underexplored due to the low incidence of HHV-8 infections. This retrospective, observational study examines twelve individuals infected with HHV-8 over seven years, focusing on patterns of co-infection and the diagnostic need for clinical management. The average age for all patients included in this study was 56 years, and a majority were male (92%). Over a majority presented with fever, night sweats, fatigue, dyspnea, and lymphadenopathy. MCD was the most common diagnosis (42%), followed by KS in the context of MCD (33%). Nearly all patients (92%) were HIV and Epstein-Barr Virus positive, with a total of 43 co-infections identified, including viral (72%), bacterial (16%), parasitic (7%), and fungal (5%) pathogens. Bacterial co-infections were more prevalent in patients diagnosed with KS than in those with MCD (p = 0.02). Given the burden of various co-infections, our findings highlight the need for comprehensive diagnostic testing to guide optimal clinical management and improve patient outcomes.

Diagnosis of Bordetella pertussis is made by using polymerase chain reaction (PCR) to detect insertion sequence 481 (IS 481 ). However, IS 481 is found in both B. pertussis and Bordetella holmesii . In a recent study, Cole et al. (Microbiol Spectr 12:e00783-24. https://doi.org/10.1128/spectrum.00783-24 ) compared the accuracy of assays performed at two different commercial laboratories that used IS 481 as a molecular target against a multiplex PCR assay performed at the Centers for Disease Control and Prevention (CDC) that can differentiate the different Bordetella species. The results demonstrated that the overall agreement among the assays from the commercial laboratories and the CDC was 85%. Only a small percentage (1.4%) of specimens positive for IS 481 were identified as B. holmesii . This study suggests that PCR tests using IS 481 as a target provide reliable diagnosis for pertussis. However, end users should recognize the limitations of PCR testing for pertussis including the inability to differentiate and monitor transmission of non-pertussis Bordetella species.

SARS-CoV-2 infection of immunocompromised individuals often leads to prolonged detection of viral RNA and infectious virus in nasal specimens, presumably due to the lack of induction of an appropriate adaptive immune response. Mutations identified in virus sequences obtained from persistently infected patients bear signatures of immune evasion and have some overlap with sequences present in variants of concern. We characterized virus isolates obtained greater than 100 days after the initial COVID-19 diagnosis from two COVID-19 patients undergoing immunosuppressive cancer therapy, wand compared them to an isolate from the start of the infection. Isolates from an individual who never mounted an antibody response specific to SARS-CoV-2 despite the administration of convalescent plasma showed slight reductions in plaque size and some showed temperature-dependent replication attenuation on human nasal epithelial cell culture compared to the virus that initiated infection. An isolate from another patient—who did mount a SARS-CoV-2 IgM response—showed temperature-dependent changes in plaque size as well as increased syncytia formation and escape from serum-neutralizing antibodies. Our results indicate that not all virus isolates from immunocompromised COVID-19 patients display clear signs of phenotypic change, but increased attention should be paid to monitoring virus evolution in this patient population.

The rapid rise in increasingly resistant bacteria has become a major threat to public health. Antimicrobial susceptibility testing (AST) is crucial in guiding appropriate therapeutic decisions and infection prevention practices for patient care. However, conventional culture-based AST methods are time-consuming and labor-intensive. Therefore, rapid AST approaches exist to address the delayed gap in time to actionable results. There are two main types of rapid AST technologies— phenotypic and genotypic approaches. In this review, we provide a summary of all commercially available rapid AST platforms for use in clinical microbiology laboratories. We describe the technologies utilized, performance characteristics, acceptable specimen types, types of resistance detected, turnaround times, limitations, and clinical outcomes driven by these rapid tests. We also discuss crucial factors to consider for the implementation of rapid AST technologies in a clinical laboratory and what the future of rapid AST holds.