233: The Background Singers of Gram-Negative Cocci
Let's Talk Micro
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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232: What’s New at ASM Microbe 2026?
Let's Talk Micro
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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231: The Hockey Puck Bug: Moraxella catarrhalis
Let's Talk Micro
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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230: Same Gram Stain, Different Story: Neisseria meningitidis vs gonorrhoeae
Let's Talk Micro
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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229: Gram-Negative Cocci: Beyond the Plate
Let's Talk Micro
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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228: Gram-Negative Cocci: What to Do After the Gram Stain
Let's Talk Micro
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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227: When Gram-Negative Cocci Show Up: How to Think at the Bench
Let's Talk Micro
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...
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226: CLSI M100 2026 Updates
Let's Talk Micro
The CLSI M100 gets updated every year—but what do those changes actually mean for the microbiology lab? In this episode of Let’s Talk Micro, Luis is joined by Dr. April Bobenchik to break down the latest updates in the CLSI M100 2026 (36th edition) and how they translate into real-world lab practice. They walk through important breakpoint changes, including aztreonam–avibactam and updates for Acinetobacter, along with new additions like trimethoprim-sulfamethoxazole breakpoints for beta-hemolytic streptococci. Another notable update this year is the updated anaerobic antibiogram and how...
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Quick Update from Let’s Talk Micro
Let's Talk Micro
Luis here with a quick update! We’re taking a short break and will return the week of March 23rd. During this time, it’s a great opportunity to explore the archive—Let’s Talk Micro has over 200 episodes covering many topics in clinical microbiology. New episodes will be back soon. Thanks for listening and for being part of the Let’s Talk Micro community. Stay connected with Let’s Talk Micro: Website: Questions or feedback? Email me at Interested in being a guest on Let’s Talk Micro? Fill out the form here: Support the podcast:
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225: Too Many Bugs, One Culture: A CMPH Guide to Wound Cultures
Let's Talk Micro
Wound cultures are some of the most complex specimens encountered in the clinical microbiology laboratory. Unlike more straightforward cultures, wound specimens often contain multiple organisms, making it challenging to determine which microbes are clinically significant and which represent colonization. In this episode of Let’s Talk Micro, Luis is joined by Dr. Christopher Doern and Dr. Alexandra Bryson to discuss the wound culture guidelines from the Clinical Microbiology Procedures Handbook (CMPH) and how they can help laboratorians navigate these challenging cultures. Together, they...
info_outlineSeason 5 premieres today!
Antimicrobial susceptibility testing (AST) is essential for guiding effective treatment—but how has it evolved, and what challenges are we still facing?
In the first episode of this series in collaboration with bioMérieux, Dr. Andrea Prinzi joins Let’s Talk Micro to explore the evolution of AST—from early methods to modern platforms like VITEK 2. We discuss the known issue of outdated breakpoints in clinical practice, the challenges with regulatory hurdles, and the impact of the 21st Century Cures Act.
What is the Cures Act, and how does it affect the way breakpoints are adopted? Why are delays still happening? And most importantly—what can laboratories, organizations, and manufacturers do to drive change?
Tune in to understand where we’ve been, where we are, and where we need to go in the world of AST.
This episode is sponsored by bioMérieux, a global innovator in infectious disease diagnostics.
Resources from bioMérieux: https://info.biomerieux.com/clin_us_2024_ams_handbook?utm_source=podcast&utm_medium=show-notes&utm_campaign=LetsTalkMicro
Additional breakpoint links: https://doi.org/10.1128/jcm.00106-25
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