Bridget Ehrig
@bridgetehrig.bsky.social
#OTILT Ceftazidime-avibactam and aztreonam is recommended by the IDSA guidance for treatment of Stenotrophomonas maltophilia due their complementary mechanisms. Avibactam inhibits L2 b-lactamases while aztreonam inhibits L1 b-lactamases, both of which allow aztreonam to reach the target site.
October 16, 2025 at 7:45 PM
#OTILT Ceftazidime-avibactam and aztreonam is recommended by the IDSA guidance for treatment of Stenotrophomonas maltophilia due their complementary mechanisms. Avibactam inhibits L2 b-lactamases while aztreonam inhibits L1 b-lactamases, both of which allow aztreonam to reach the target site.
#OTILT PCT is a biomarker in systemic bacterial infection, especially in respiratory infections and sepsis. But its accuracy is limited by false positives (surgery/trauma, burns, pancreatitis, immunotherapy, ESRD) and lack of validation in immunocompromised, pregnant, and neonatal populations.
October 15, 2025 at 5:49 PM
#OTILT PCT is a biomarker in systemic bacterial infection, especially in respiratory infections and sepsis. But its accuracy is limited by false positives (surgery/trauma, burns, pancreatitis, immunotherapy, ESRD) and lack of validation in immunocompromised, pregnant, and neonatal populations.
#OTILT S. ugdunensis is a coagulase-negative staphylococcus (CoNS), but unlike most, it behaves clinically like S. aureus—causing aggressive infections. Even if isolated from a single bottle, it should be treated as clinically significant. It is typically highly susceptible (~95%) to β-lactams.
October 10, 2025 at 3:48 PM
#OTILT S. ugdunensis is a coagulase-negative staphylococcus (CoNS), but unlike most, it behaves clinically like S. aureus—causing aggressive infections. Even if isolated from a single bottle, it should be treated as clinically significant. It is typically highly susceptible (~95%) to β-lactams.
#OTILT2 INSTIs can cause a mild, nonpathologic rise in serum creatinine due to inhibited tubular secretion rather than true renal injury. Other class effects include weight gain and interactions with polyvalent ions, while bictegravir/dolutegravir may also cause headache and insomnia.
October 9, 2025 at 6:49 PM
#OTILT2 INSTIs can cause a mild, nonpathologic rise in serum creatinine due to inhibited tubular secretion rather than true renal injury. Other class effects include weight gain and interactions with polyvalent ions, while bictegravir/dolutegravir may also cause headache and insomnia.
#OTILT Bilirubin acts as a potent free radical scavenger, and studies show that bilirubin nanoparticles can reduce oxidative stress and myocardial injury — supporting the cardioprotective effects observed with PIs.
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Bilirubin Nanoparticles Protect Against Cardiac Ischemia/Reperfusion Injury in Mice
Ischemia/reperfusion (I/R) injury causes overproduction of reactive oxygen species, which are the major culprits of oxidative stress that leads to inflammation, apoptosis, myocardial damage, and dysfu...
pmc.ncbi.nlm.nih.gov
October 9, 2025 at 6:43 PM
#OTILT Bilirubin acts as a potent free radical scavenger, and studies show that bilirubin nanoparticles can reduce oxidative stress and myocardial injury — supporting the cardioprotective effects observed with PIs.
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
#OTILT Allogeneic SCT (closet match) are the safest. Autologous SCT (patient’s own cells) lowers GVHD risk but increases relapse risk. Haploidentical transplants (50% match) carry high risk of GVHD and infection. Cord blood SCT lower GVHD risk (cells are adaptable) but have higher infection risk.
October 8, 2025 at 4:54 PM
#OTILT Allogeneic SCT (closet match) are the safest. Autologous SCT (patient’s own cells) lowers GVHD risk but increases relapse risk. Haploidentical transplants (50% match) carry high risk of GVHD and infection. Cord blood SCT lower GVHD risk (cells are adaptable) but have higher infection risk.
#OTILT Distributive shock (sepsis neurogenic) involves low afterload due to systemic vasodilation. Hypovolemic shock results from decreased preload and is managed with fluid resuscitation. Cardiogenic shock occurs when cardiac output is reduced and is treated with inotropes/revascularization.
October 7, 2025 at 5:14 PM
#OTILT Distributive shock (sepsis neurogenic) involves low afterload due to systemic vasodilation. Hypovolemic shock results from decreased preload and is managed with fluid resuscitation. Cardiogenic shock occurs when cardiac output is reduced and is treated with inotropes/revascularization.
#OTILT For MRSA infections not responding to vancomycin, combination therapy with ceftaroline plus daptomycin or linezolid has shown improved clearance in persistent bacteremia. Patients with driveline infections often require indefinite therapy since the line cannot be removed.
October 6, 2025 at 7:53 PM
#OTILT For MRSA infections not responding to vancomycin, combination therapy with ceftaroline plus daptomycin or linezolid has shown improved clearance in persistent bacteremia. Patients with driveline infections often require indefinite therapy since the line cannot be removed.
#OTILT High-dose acyclovir can cause AMS due to neurotoxicity. Clinical features can include agitation, tremors, hallucinations, delirium, and even coma. Importantly, these symptoms may mimic infectious or neurologic causes such as herpes encephalitis, making diagnosis challenging.
October 2, 2025 at 4:45 PM
#OTILT High-dose acyclovir can cause AMS due to neurotoxicity. Clinical features can include agitation, tremors, hallucinations, delirium, and even coma. Importantly, these symptoms may mimic infectious or neurologic causes such as herpes encephalitis, making diagnosis challenging.
#OTILT Exposed bone in a sacral pressure ulcer does not automatically mean osteomyelitis. Antibiotics alone don’t improve outcomes unless a surgical flap procedure is performed to cover the ulcer, making treatment of the infection worthwhile.
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Osteomyelitis Complicating Sacral Pressure Ulcers: Whether or Not to Treat With Antibiotic Therapy
We conducted a systematic literature review and found no data supporting benefit of antibacterial therapy for osteomyelitis in the setting of sacral pressure ulcers absent wound coverage. If wound cov...
pmc.ncbi.nlm.nih.gov
October 1, 2025 at 4:09 PM
#OTILT Exposed bone in a sacral pressure ulcer does not automatically mean osteomyelitis. Antibiotics alone don’t improve outcomes unless a surgical flap procedure is performed to cover the ulcer, making treatment of the infection worthwhile.
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
#OTILT Obesity, inflammation, smoking, and old age can raise cystatin C and make eGFRcys appear lower than eGFRcr. If there’s >15 mL/min/1.73m² difference between the two, calculate eGFRcr-cys, which is more accurate for guiding clinical decisions.
Cite: www.kidney-international.org/article/S008...
Cite: www.kidney-international.org/article/S008...
KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease
This article is published as part of a supplement sponsored by Kidney Disease: Improving
Global Outcomes (KDIGO). The opinions or views expressed in this supplement are those
of the authors and do not...
www.kidney-international.org
September 30, 2025 at 6:01 PM
#OTILT Obesity, inflammation, smoking, and old age can raise cystatin C and make eGFRcys appear lower than eGFRcr. If there’s >15 mL/min/1.73m² difference between the two, calculate eGFRcr-cys, which is more accurate for guiding clinical decisions.
Cite: www.kidney-international.org/article/S008...
Cite: www.kidney-international.org/article/S008...
#OTILT False positives in BDG testing can occur with gauze, albumin, and β-lactam antibiotics (e.g., ampicillin-sulbactam, amox-clav). Other reported causes include IVIG, cellulose filters, and some bacterial infections, making poor specificity a major limitation.
September 29, 2025 at 5:43 PM
#OTILT False positives in BDG testing can occur with gauze, albumin, and β-lactam antibiotics (e.g., ampicillin-sulbactam, amox-clav). Other reported causes include IVIG, cellulose filters, and some bacterial infections, making poor specificity a major limitation.
#OTILT P. vulgaris (indole-positive Proteus) is included in SPACE organisms -“at risk” for inducible AmpC -but it more often produces an inducible class A β-lactamase. Clinically, it should still be managed like other SPACE organisms, since this inducible resistance can compromise β-lactam therapy
September 26, 2025 at 6:33 PM
#OTILT P. vulgaris (indole-positive Proteus) is included in SPACE organisms -“at risk” for inducible AmpC -but it more often produces an inducible class A β-lactamase. Clinically, it should still be managed like other SPACE organisms, since this inducible resistance can compromise β-lactam therapy
#OTILT Avibactam is one of the broadest β-lactamase inhibitors, covering KPC, most OXA-48, and ESBLs (but not MBLs), whereas tazobactam has narrower coverage—mainly ESBLs—and misses most carbapenemases.
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Ceftazidime/Avibactam and Ceftolozane/Tazobactam: Second-generation β-Lactam/β-Lactamase Inhibitor Combinations
Ceftolozane/tazobactam and ceftazidime/avibactam are second-generation β-lactam/β-lactamase combination antibiotics with in vitro activity against multidrug-resistant gram-negative bacteria, including...
pmc.ncbi.nlm.nih.gov
September 25, 2025 at 6:06 PM
#OTILT Avibactam is one of the broadest β-lactamase inhibitors, covering KPC, most OXA-48, and ESBLs (but not MBLs), whereas tazobactam has narrower coverage—mainly ESBLs—and misses most carbapenemases.
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
Cite: pmc.ncbi.nlm.nih.gov/articles/PMC...
#OTILT Lactulose lowers ammonia by converting it to ammonium, which is trapped in the gut and excreted, while rifaximin reduces ammonia production by killing gut bacteria. Together, they decrease systemic ammonia levels, which is key in managing hepatic encephalopathy.
September 24, 2025 at 6:53 PM
#OTILT Lactulose lowers ammonia by converting it to ammonium, which is trapped in the gut and excreted, while rifaximin reduces ammonia production by killing gut bacteria. Together, they decrease systemic ammonia levels, which is key in managing hepatic encephalopathy.
#OTILT Cirrhosis causes scarring that obstructs blood flow through the liver, leading to portal hypertension. This increased pressure forces blood into collateral veins (varices) in the esophagus or stomach, which can rupture and cause GI bleeding, often presenting as coffee-ground emesis.
September 23, 2025 at 3:33 PM
#OTILT Cirrhosis causes scarring that obstructs blood flow through the liver, leading to portal hypertension. This increased pressure forces blood into collateral veins (varices) in the esophagus or stomach, which can rupture and cause GI bleeding, often presenting as coffee-ground emesis.
#OTILT- There is an increased risk of neurological dysfunction associated with cefepime vs. piperacillin-tazobactam; however, no significant difference in AKI incidence - as demonstrated by the ACORN Trial.
Cite: Incidence - as demonstrated by the ACORN Trial.
jamanetwork.com/journals/jam...
Cite: Incidence - as demonstrated by the ACORN Trial.
jamanetwork.com/journals/jam...
Cefepime vs Piperacillin-Tazobactam in Adults Hospitalized With Acute Infection
This randomized clinical trial compares the use of cefepime vs piperacillin-tazobactam and the risk of acute kidney injury and neurological dysfunction in adults hospitalized with acute infection.
jamanetwork.com
September 22, 2025 at 7:15 PM
#OTILT- There is an increased risk of neurological dysfunction associated with cefepime vs. piperacillin-tazobactam; however, no significant difference in AKI incidence - as demonstrated by the ACORN Trial.
Cite: Incidence - as demonstrated by the ACORN Trial.
jamanetwork.com/journals/jam...
Cite: Incidence - as demonstrated by the ACORN Trial.
jamanetwork.com/journals/jam...
#OTILT First-line hepC tx (Mavyret and Epclusa) are pan-genotypic. If a pt develops hepC again, genotyping is useful since it determines whether infection is a recurrence or a new infection - which guides whether the pt should receive standard first-line therapy again or move to a salvage regimen.
September 19, 2025 at 7:43 PM
#OTILT First-line hepC tx (Mavyret and Epclusa) are pan-genotypic. If a pt develops hepC again, genotyping is useful since it determines whether infection is a recurrence or a new infection - which guides whether the pt should receive standard first-line therapy again or move to a salvage regimen.
#OTILT- Voriconazole is primarily metabolized by CYP2C9 and CYP2C19, with CYP2C19 genetic polymorphisms leading to significant variability in drug levels. Poor metabolizers can develop elevated concentrations and toxicity, while rapid metabolizers may have subtherapeutic exposure.
September 18, 2025 at 8:10 PM
#OTILT- Voriconazole is primarily metabolized by CYP2C9 and CYP2C19, with CYP2C19 genetic polymorphisms leading to significant variability in drug levels. Poor metabolizers can develop elevated concentrations and toxicity, while rapid metabolizers may have subtherapeutic exposure.
#OTILT Linezolid 600 mg once daily can be used as suppressive therapy, with similar rates of culture conversion (85.6% vs 95.1%, p=0.0948) and tx success (76.1% vs 89.5%, p=0.0695) compared to higher doses. However, once-daily dosing is associated with less myelosuppression (19.6% vs 50%, p<0.0001).
September 17, 2025 at 6:16 PM
#OTILT Linezolid 600 mg once daily can be used as suppressive therapy, with similar rates of culture conversion (85.6% vs 95.1%, p=0.0948) and tx success (76.1% vs 89.5%, p=0.0695) compared to higher doses. However, once-daily dosing is associated with less myelosuppression (19.6% vs 50%, p<0.0001).
#OTILT CLABSI occurs when bacteria seeds the bloodstream via an indwelling catheter. If the infection is due to S. epidermidis, treatment duration is 5–7 days after removal of the line. If the infection is caused by S. aureus, even if the line is removed, at least 14 days of therapy is required
September 16, 2025 at 7:49 PM
#OTILT CLABSI occurs when bacteria seeds the bloodstream via an indwelling catheter. If the infection is due to S. epidermidis, treatment duration is 5–7 days after removal of the line. If the infection is caused by S. aureus, even if the line is removed, at least 14 days of therapy is required
#OTILT I learned that blood culture negative endocarditis (BCNE) can occur when infective endocarditis is caused by organisms that do not grow in routine blood or valve cultures, like Bartonella spp., Coxiella burnetii, Chlamydia spp. + Tropheryma whipplei.
Cite: www.ahajournals.org/doi/10.1161/...
Cite: www.ahajournals.org/doi/10.1161/...
Blood Culture–Negative Endocarditis: A Scientific Statement From the American Heart Association | Journal of the American Heart Association
www.ahajournals.org
September 15, 2025 at 6:38 PM
#OTILT I learned that blood culture negative endocarditis (BCNE) can occur when infective endocarditis is caused by organisms that do not grow in routine blood or valve cultures, like Bartonella spp., Coxiella burnetii, Chlamydia spp. + Tropheryma whipplei.
Cite: www.ahajournals.org/doi/10.1161/...
Cite: www.ahajournals.org/doi/10.1161/...
#OTILT A PET-CT scan measures glucose metabolism in tissues, which is why patients follow a low-glucose diet before. Sites of high uptake indicate increased metabolism, such as immune cells or rapidly dividing tumor cells. This makes PET-CT useful in both oncology and infection/inflamm imaging.
September 12, 2025 at 6:22 PM
#OTILT A PET-CT scan measures glucose metabolism in tissues, which is why patients follow a low-glucose diet before. Sites of high uptake indicate increased metabolism, such as immune cells or rapidly dividing tumor cells. This makes PET-CT useful in both oncology and infection/inflamm imaging.
#OTILT - Clindamycin plays a key role in necrotizing fasciitis because it suppresses GAS toxin production. Empirically, it can be combined with a broad β-lactam to cover polymicrobial causes, but once group A streptococcus is confirmed, guidelines recommend narrowing to penicillin + clindamycin.
September 11, 2025 at 6:10 PM
#OTILT - Clindamycin plays a key role in necrotizing fasciitis because it suppresses GAS toxin production. Empirically, it can be combined with a broad β-lactam to cover polymicrobial causes, but once group A streptococcus is confirmed, guidelines recommend narrowing to penicillin + clindamycin.
#OTILT: Patient's with diabetic foot infections undergoing amputation: antibiotic duration depends on residual infection: 3–5 days if both infected bone and soft tissue are fully resected, 10–14 days if residual soft tissue infection remains, and up to 6 weeks if residual osteomyelitis is present.
September 10, 2025 at 7:01 PM
#OTILT: Patient's with diabetic foot infections undergoing amputation: antibiotic duration depends on residual infection: 3–5 days if both infected bone and soft tissue are fully resected, 10–14 days if residual soft tissue infection remains, and up to 6 weeks if residual osteomyelitis is present.