227: When Gram-Negative Cocci Show Up: How to Think at the Bench
Release Date: 04/02/2026
Let's Talk Micro
In Part 2 of this hantavirus series, Luis continues the conversation with Dr. Ryan Relich and Dr. Stephanie Seifert by focusing on the recent Andes virus cruise ship outbreak and what makes this hantavirus different from others. The discussion explores the outbreak investigation, the evidence for person-to-person transmission, and why the Andes virus has received so much attention from the public health community. Ryan and Stephanie also discuss diagnostic testing, including PCR and serology, the role of public health laboratories, current treatment options, prevention strategies, and how...
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Hantaviruses have recently been in the headlines, but what exactly are they and how do they spread? In Part 1 of this hantavirus series, Luis is joined by Dr. Ryan Relich and Dr. Stephanie Seifert for a deep dive into the world of hantaviruses. The conversation explores the basics of hantaviruses, including their ecology, rodent reservoirs, transmission, and the diseases they cause in humans. The guests also discuss Old World vs New World hantaviruses, hantavirus pulmonary syndrome (HPS), environmental risk factors, climate influences, and why these infections may be underdiagnosed. From deer...
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Workforce shortages continue to impact clinical laboratories across the country, especially in rural healthcare settings. In this episode of Let’s Talk Micro, Luis is joined by Kenzi Haigler to discuss an innovative high school laboratory program designed to introduce students to laboratory medicine early and help strengthen the future workforce pipeline. Kenzi shares her journey into the laboratory profession, her experiences working in rural healthcare, and the unique challenges small hospitals face when it comes to staffing, training, and retaining laboratory professionals. She also...
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In this episode of Let’s Talk Micro, we close out our gram-negative cocci series by talking about the “background singers” of the group—the organisms that quietly show up on respiratory cultures and oral flora plates every day. We explore the world of non-pathogenic Neisseria species, along with rod-shaped and coccobacillary Neisseria and Moraxella that break the classic gram-negative diplococci rule. From commensals and opportunistic pathogens to their role in respiratory cultures and bench identification, this episode focuses on how to think through these isolates in the clinical...
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This week, Let’s Talk Micro is pausing the Gram-negative cocci series to talk about one of the biggest microbiology meetings of the year: ASM Microbe 2026. Luis is joined by Dr. Bobbi Pritt and Dr. Robert Tibbetts to discuss what attendees can expect from this year’s meeting in Washington, DC. The conversation covers the new meeting structure, important trends in clinical microbiology, sessions and workshops geared toward medical laboratory scientists, networking opportunities, and tips for getting the most out of the conference experience. They also discuss hot topics such as AI-driven...
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In this episode of Let’s Talk Micro, we continue our gram-negative cocci series with a closer look at Moraxella catarrhalis—better known at the bench as the hockey puck bug. We break down what makes this organism unique, from its classic sliding colony morphology to how it behaves in different patient populations. Is it a colonizer or a pathogen? The answer depends on the clinical context. We walk through its role in pediatric infections like otitis media and sinusitis, its significance in adults—especially in COPD—and how to interpret its presence in respiratory cultures. As always,...
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In this week’s episode, we continue our series on gram-negative cocci and take a closer look at two of the most important organisms: Neisseria meningitidis and Neisseria gonorrhoeae. On the Gram stain, they may look the same—but clinically, they represent very different scenarios. We walk through colonization, transmission, and key virulence factors, and connect them to the infections they cause—from meningitis and invasive disease to mucosal and disseminated gonococcal infections. We also bring it back to the bench, discussing specimen source, testing approaches like NAAT and culture,...
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In this episode we continue our gram-negative cocci series by moving beyond the plate and into modern identification methods. From traditional systems like VITEK and RapID NH to MALDI-TOF and molecular testing, we explore how these organisms are identified in today’s clinical microbiology lab. We also break down the role of NAATs and syndromic panels in detecting organisms like Neisseria meningitidis and Neisseria gonorrhoeae, especially in situations where culture may be delayed or negative. This episode focuses on how these tools fit into real-world workflows—highlighting their...
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In this episode of Let’s Talk Micro, we continue our gram-negative cocci series by focusing on what to do after the Gram stain. You’ve identified gram-negative cocci—now what? We take a practical, bench-focused approach to working these organisms up, covering key culture media like blood agar, chocolate agar, and selective media such as Modified Thayer-Martin and Martin-Lewis. We also review collection and transport considerations, including JEMBEC and CO₂ requirements for Neisseria gonorrhoeae. We then dive into commonly used tests, including ONPG for differentiating Neisseria...
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In this episode of Let’s Talk Micro, we kick off a new series on gram-negative cocci by starting where it all begins—the Gram stain. Seeing gram-negative diplococci on a smear can feel intimidating, especially when you’re on the bench and need to make the right call. In this episode, we focus on how to approach that moment with confidence. We walk through the key organisms you’ll encounter, including Neisseria, Moraxella, and Veillonella, and discuss how morphology, specimen source, and clinical context all come together to guide your thinking. We also revisit a correction from a...
info_outlineIn this episode of Let’s Talk Micro, we kick off a new series on gram-negative cocci by starting where it all begins—the Gram stain.
Seeing gram-negative diplococci on a smear can feel intimidating, especially when you’re on the bench and need to make the right call. In this episode, we focus on how to approach that moment with confidence. We walk through the key organisms you’ll encounter, including Neisseria, Moraxella, and Veillonella, and discuss how morphology, specimen source, and clinical context all come together to guide your thinking. We also revisit a correction from a previous episode regarding carbohydrate utilization in Neisseria species.
This episode is all about building a strong foundation—how to think before jumping to identification.
Stay tuned for the next episode, where we’ll dive into the media and tests used to identify these organisms in the lab.
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