This Week in Infectious Disease — Oct 30, 2026
Generated Oct 31, 2026 · 11:05
The week's practice-changing Infectious Disease research, summarized for clinicians.
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Cefepime-Zidebactam for Infections Caused by Carbapenem-Resistant Gram-Negative Bacteria, Including Metallo-β-Lactamase Producers: A Phase 2, Open-Label, Single-Arm, Multicenter Study.
In a single-arm phase 2 trial of mostly metallo-beta-lactamase infections, cefepime-zidebactam achieved about 92 percent investigator-assessed cure and 87 percent adjudicated cure, with low mortality, pending comparative trials.
Clinical Infectious Diseases · 2026 · PubMed
This week’s papers
- 01
Cefepime-Zidebactam for Infections Caused by Carbapenem-Resistant Gram-Negative Bacteria, Including Metallo-β-Lactamase Producers: A Phase 2, Open-Label, Single-Arm, Multicenter Study.
In a single-arm phase 2 trial of mostly metallo-beta-lactamase infections, cefepime-zidebactam achieved about 92 percent investigator-assessed cure and 87 percent adjudicated cure, with low mortality, pending comparative trials.
Krishnaswami RK et al. · Clinical Infectious Diseases · 2026
From the briefingIn Clinical Infectious Diseases, Krishnaswami and colleagues report a phase 2, open-label, single-arm multicenter study of intravenous cefepime-zidebactam in adults with carbapenem-resistant gram-negative infections [1]. Of 68 qualifying isolates, more than four in five were metallo-beta-lactamase producers, mostly NDM, and complicated urinary tract infection or pyelonephritis made up a majority of the evaluable cases. Investigator-assessed clinical cure at test of cure was about 92 percent in the 60 evaluable patients, and roughly 94 percent in the subgroup with metallo-beta-lactamase pathogens. An external adjudication committee was somewhat less generous, putting cure at about 87 percent. Twenty-eight day mortality was under three percent, and serious drug-related adverse events were similarly uncommon. Those are encouraging numbers, but the design matters: there was no comparator, the cohort skewed toward urinary infections, and the adjudicated figures were post hoc, so this is signal-generating evidence rather than proof of superiority over existing combinations.
If you only have time for one paper this week, make it the cefepime-zidebactam study in Clinical Infectious Diseases [1]. It offers the first prospective clinical cure data for an agent targeting metallo-beta-lactamase producers in a population dominated by NDM, and reopens the question of what the preferred backbone for these infections should be.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 02
Cefiderocol for the treatment of bloodstream infection due to MBL-producing Enterobacterales: a single-center retrospective cohort.
Among 19 patients with metallo-beta-lactamase Enterobacterales bacteremia, cefiderocol cured 15 by day 14, but resistance emerged on therapy in three of four failures, mainly NDM/OXA-48-like Klebsiella.
Boán J et al. · International Journal of Antimicrobial Agents · 2026
From the briefingA smaller real-world counterpoint comes from the International Journal of Antimicrobial Agents, where Boán and colleagues describe 19 patients with bloodstream infection due to metallo-beta-lactamase producing Enterobacterales treated with cefiderocol at a single centre [2]. Most of these patients were immunosuppressed and Klebsiella dominated, largely VIM producers. Clinical cure by day 14 was achieved in 15 of the 19 patients, and two patients died. The finding that stands out is resistance: cefiderocol resistance emerged during therapy in three of the four patients who were not cured, mainly in Klebsiella pneumoniae co-producing NDM and OXA-48-like enzymes. With 19 patients and no comparator, this cannot define cefiderocol's place, but it adds to concern about treatment-emergent resistance in exactly the hardest isolates.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 03
Gram-Negative Bacterial Resistance.
A review of gram-negative resistance mechanisms and key pathogens argues management depends on rapid diagnostics, targeted use of newer beta-lactams, source control, and judicious treatment durations.
Tamma PD · New England Journal of Medicine · 2026
From the briefingFraming both studies is a New England Journal of Medicine review by Tamma on gram-negative resistance [3], which walks through mechanisms from efflux to enzymatic inactivation and argues that management rests on timely, accurate diagnostics, targeted use of newer beta-lactam agents, source control, and judicious treatment durations. Read together, these papers suggest the pipeline for metallo-beta-lactamase infections is widening, while reminding us that neither newer agent yet has randomized evidence in bacteremic, critically ill patients.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 04
Performance of the recent Duke criteria versions in patients with suspected infective endocarditis and sufficient cardiac imaging: The more things change, the more they remain the same.
In nearly 3,500 imaged suspected endocarditis episodes, the 2023 Duke criteria raised sensitivity but lowered specificity, and roughly a third of episodes still remained classified as possible endocarditis.
Stavropoulou E et al. · Clinical Infectious Diseases · 2026
From the briefingIn Clinical Infectious Diseases, Stavropoulou and colleagues tested the 2015 Duke-ESC criteria against the newer 2023 Duke-ISCVID and 2023 Duke-ESC versions in nearly 3,500 suspected endocarditis episodes from two Swiss university hospitals, all with guideline-concordant multimodality cardiac imaging, using the Endocarditis Team's final diagnosis as the reference [4]. Both 2023 versions improved sensitivity for definite endocarditis, by roughly ten points, to the low seventies. But that gain came with lost specificity, and the proportion of episodes stuck in the possible category barely moved, remaining close to a third under the ISCVID version. The authors' title, the more things change, the more they remain the same, captures the message: the revisions catch more true cases but have not shrunk the diagnostic gray zone. This is retrospective and single-country, yet the size of the cohort makes it hard to dismiss.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 05
External Validation of the PACTO Risk Score for Infective Endocarditis in Patients With Coagulase-Negative Staphylococcal Bacteremia: A Multicenter Cohort Study.
In 302 patients with coagulase-negative staphylococcal bacteremia, the PACTO score discriminated endocarditis well, and scores below 2 carried a 98 percent negative predictive value, though prospective validation is pending.
Ramos-Martínez A et al. · Open Forum Infectious Diseases · 2026
From the briefingA more targeted tool comes from Open Forum Infectious Diseases, where Ramos-Martínez and colleagues externally validated the PACTO score in 302 adults with true coagulase-negative staphylococcal bacteremia across several Spanish hospitals [5]. The score awards points for a prosthetic valve or pacemaker, all blood culture bottles positive, community acquisition, and continuous bacteremia. About a fifth of patients had definite endocarditis, and discrimination was strong. Endocarditis prevalence climbed from under two percent in the lowest category to about 85 percent in the highest, and a score below 2 carried a negative predictive value of about 98 percent. The authors argue this supports deferring echocardiography in low-risk patients, though they themselves call for prospective validation before that becomes standard.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 06
State-of-the-Art Review: Native Joint Septic Arthritis Epidemiology, Pathogenesis, Microbiology, Diagnosis, Management, and Outcomes.
A review of native joint septic arthritis highlights the absence of validated diagnostic criteria and evidence gaps in surgical timing, treatment duration, oral step-down, and emerging molecular diagnostics.
Khodadadi RB et al. · Clinical Infectious Diseases · 2026
From the briefingRounding out the theme, Khodadadi and colleagues offer a state-of-the-art review of native joint septic arthritis, again in Clinical Infectious Diseases [6]. They emphasise that there are still no validated diagnostic criteria, that culture has real limits, and that molecular diagnostics are expanding, while flagging persistent evidence gaps in surgical timing, treatment duration, and oral step-down. Across these three papers, the common thread is that diagnostic classification remains a weak link in deep infection.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 07
Antenatal Screening for Sexually Transmitted Infections to Reduce Preterm Birth or Low Birthweight (Philani Ndiphile Study): A Randomized 3-Group Trial.
Antenatal screening for chlamydia, gonorrhoea, and trichomonas did not reduce composite preterm birth or low birthweight, though repeat screening lowered preterm birth by about a quarter as a secondary outcome.
Medina-Marino A et al. · Clinical Infectious Diseases · 2026
From the briefingThe Philani Ndiphile study in Clinical Infectious Diseases, led by Medina-Marino, randomized over 2,200 pregnant women in South Africa to one-time screening for chlamydia, gonorrhoea, and trichomonas, screening repeated at 30 to 34 weeks, or syndromic management [7]. Neither screening strategy reduced the primary composite of preterm birth or low birthweight, and neither affected low birthweight alone. The two-time strategy did reduce preterm birth by about a quarter, but that was a secondary outcome, so it is hypothesis-generating rather than decisive. The trial tempers expectations that antenatal STI screening by itself will move birth outcomes.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 08
Does pre-treatment with doxycycline improve the efficacy of combination minocycline and metronidazole for macrolide-resistant Mycoplasma genitalium infections?
Minocycline plus metronidazole cured about 81 percent of macrolide-resistant Mycoplasma genitalium infections, and doxycycline pre-treatment did not significantly improve overall cure in this larger cohort.
Htaik K et al. · Antimicrobial Agents and Chemotherapy · 2026
From the briefingIn Antimicrobial Agents and Chemotherapy, Htaik and colleagues examined a 14-day regimen of minocycline plus metronidazole for macrolide-resistant Mycoplasma genitalium in 262 patients [8]. An earlier, smaller dataset from the same group had hinted that seven days of doxycycline pre-treatment boosted cure; in this larger cohort it did not, with cure around 80 percent with or without doxycycline. Patients who had failed prior regimens did appear to benefit from pre-treatment, and cervicovaginal infections responded better than urethral ones. This is observational, but it positions a generic, widely accessible combination as a credible option for dual-class resistant infection.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 09
Virological outcomes, resistance profile and viral evolution of lenacapavir-based regimens in heavily treatment-experienced people: data from the PRESTIGIO Registry.
In nine heavily treatment-experienced people with multidrug-resistant HIV, lenacapavir regimens maintained or achieved suppression in most, with high-level resistance emerging only in one poorly adherent patient.
Santoro MM et al. · Journal of Antimicrobial Chemotherapy · 2026
From the briefingFinally, from the Journal of Antimicrobial Chemotherapy, Santoro and colleagues report real-world resistance data on the long-acting capsid inhibitor lenacapavir in nine heavily treatment-experienced people with multidrug-resistant HIV from the Italian PRESTIGIO Registry [9]. Over a median of about 20 months, both patients who started suppressed stayed suppressed, and six of the seven viremic patients achieved suppression. One poorly adherent patient developed Q67K and K70H, conferring a roughly two-thousand-fold loss of susceptibility. With nine patients this is a case series, but it suggests limited viral evolution with adherence and high-level resistance without it.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
- 10
Impact of a large measles outbreak associated with transmission in the Americas and Canada's loss of measles elimination status: descriptive cohort study.
An Ontario measles outbreak of 2,377 mostly unvaccinated cases in under-vaccinated communities caused hospitalisations and an infant death, spread internationally, and contributed to Canada losing elimination status.
Wilson SE et al. · BMJ · 2026
From the briefingWe close with public health. In the BMJ, Wilson and colleagues describe the Ontario measles outbreak that contributed to Canada losing its elimination status [10]. Over 49 weeks there were 2,377 cases, and about nine in ten cases occurred in historically under-vaccinated communities, with limited spillover into the broader population. Nearly three quarters of cases were in people aged 19 or younger, and close to nine in ten cases were unvaccinated. There were 166 hospital admissions, 10 congenital infections, one case of encephalitis, and one infant death. Sequencing identified a novel strain later detected in the United States, Mexico, and the Netherlands. The authors argue that elimination is fragile where long-standing immunity gaps persist across interconnected communities, and that culturally appropriate engagement is central to closing them.
Written by AI from the published abstract, for healthcare professionals. Not medical advice; check the paper before acting on it.
The full briefing
This AudioScholar briefing is generated by artificial intelligence for healthcare professionals and trainees. It is not medical advice.
Welcome to This Week in Infectious Disease. This week we're covering 10 notable papers spanning treatment of carbapenem-resistant gram-negative infections, diagnostic tools for endocarditis and joint infection, and sexually transmitted infections, HIV, and the return of measles. Let's dive in.
We start with metallo-beta-lactamase producers, the resistance mechanism that still leaves clinicians with the fewest options. In Clinical Infectious Diseases, Krishnaswami and colleagues report a phase 2, open-label, single-arm multicenter study of intravenous cefepime-zidebactam in adults with carbapenem-resistant gram-negative infections [1]. Of 68 qualifying isolates, more than four in five were metallo-beta-lactamase producers, mostly NDM, and complicated urinary tract infection or pyelonephritis made up a majority of the evaluable cases. Investigator-assessed clinical cure at test of cure was about 92 percent in the 60 evaluable patients, and roughly 94 percent in the subgroup with metallo-beta-lactamase pathogens. An external adjudication committee was somewhat less generous, putting cure at about 87 percent. Twenty-eight day mortality was under three percent, and serious drug-related adverse events were similarly uncommon. Those are encouraging numbers, but the design matters: there was no comparator, the cohort skewed toward urinary infections, and the adjudicated figures were post hoc, so this is signal-generating evidence rather than proof of superiority over existing combinations. A smaller real-world counterpoint comes from the International Journal of Antimicrobial Agents, where Boán and colleagues describe 19 patients with bloodstream infection due to metallo-beta-lactamase producing Enterobacterales treated with cefiderocol at a single centre [2]. Most of these patients were immunosuppressed and Klebsiella dominated, largely VIM producers. Clinical cure by day 14 was achieved in 15 of the 19 patients, and two patients died. The finding that stands out is resistance: cefiderocol resistance emerged during therapy in three of the four patients who were not cured, mainly in Klebsiella pneumoniae co-producing NDM and OXA-48-like enzymes. With 19 patients and no comparator, this cannot define cefiderocol's place, but it adds to concern about treatment-emergent resistance in exactly the hardest isolates. Framing both studies is a New England Journal of Medicine review by Tamma on gram-negative resistance [3], which walks through mechanisms from efflux to enzymatic inactivation and argues that management rests on timely, accurate diagnostics, targeted use of newer beta-lactam agents, source control, and judicious treatment durations. Read together, these papers suggest the pipeline for metallo-beta-lactamase infections is widening, while reminding us that neither newer agent yet has randomized evidence in bacteremic, critically ill patients.
Our second theme is diagnosis in deep-seated staphylococcal and bacterial infection, where the tools we rely on are imperfect. In Clinical Infectious Diseases, Stavropoulou and colleagues tested the 2015 Duke-ESC criteria against the newer 2023 Duke-ISCVID and 2023 Duke-ESC versions in nearly 3,500 suspected endocarditis episodes from two Swiss university hospitals, all with guideline-concordant multimodality cardiac imaging, using the Endocarditis Team's final diagnosis as the reference [4]. Both 2023 versions improved sensitivity for definite endocarditis, by roughly ten points, to the low seventies. But that gain came with lost specificity, and the proportion of episodes stuck in the possible category barely moved, remaining close to a third under the ISCVID version. The authors' title, the more things change, the more they remain the same, captures the message: the revisions catch more true cases but have not shrunk the diagnostic gray zone. This is retrospective and single-country, yet the size of the cohort makes it hard to dismiss. A more targeted tool comes from Open Forum Infectious Diseases, where Ramos-Martínez and colleagues externally validated the PACTO score in 302 adults with true coagulase-negative staphylococcal bacteremia across several Spanish hospitals [5]. The score awards points for a prosthetic valve or pacemaker, all blood culture bottles positive, community acquisition, and continuous bacteremia. About a fifth of patients had definite endocarditis, and discrimination was strong. Endocarditis prevalence climbed from under two percent in the lowest category to about 85 percent in the highest, and a score below 2 carried a negative predictive value of about 98 percent. The authors argue this supports deferring echocardiography in low-risk patients, though they themselves call for prospective validation before that becomes standard. Rounding out the theme, Khodadadi and colleagues offer a state-of-the-art review of native joint septic arthritis, again in Clinical Infectious Diseases [6]. They emphasise that there are still no validated diagnostic criteria, that culture has real limits, and that molecular diagnostics are expanding, while flagging persistent evidence gaps in surgical timing, treatment duration, and oral step-down. Across these three papers, the common thread is that diagnostic classification remains a weak link in deep infection.
Our third theme covers sexually transmitted infections and HIV, with one sobering trial and two treatment datasets. The Philani Ndiphile study in Clinical Infectious Diseases, led by Medina-Marino, randomized over 2,200 pregnant women in South Africa to one-time screening for chlamydia, gonorrhoea, and trichomonas, screening repeated at 30 to 34 weeks, or syndromic management [7]. Neither screening strategy reduced the primary composite of preterm birth or low birthweight, and neither affected low birthweight alone. The two-time strategy did reduce preterm birth by about a quarter, but that was a secondary outcome, so it is hypothesis-generating rather than decisive. The trial tempers expectations that antenatal STI screening by itself will move birth outcomes. In Antimicrobial Agents and Chemotherapy, Htaik and colleagues examined a 14-day regimen of minocycline plus metronidazole for macrolide-resistant Mycoplasma genitalium in 262 patients [8]. An earlier, smaller dataset from the same group had hinted that seven days of doxycycline pre-treatment boosted cure; in this larger cohort it did not, with cure around 80 percent with or without doxycycline. Patients who had failed prior regimens did appear to benefit from pre-treatment, and cervicovaginal infections responded better than urethral ones. This is observational, but it positions a generic, widely accessible combination as a credible option for dual-class resistant infection. Finally, from the Journal of Antimicrobial Chemotherapy, Santoro and colleagues report real-world resistance data on the long-acting capsid inhibitor lenacapavir in nine heavily treatment-experienced people with multidrug-resistant HIV from the Italian PRESTIGIO Registry [9]. Over a median of about 20 months, both patients who started suppressed stayed suppressed, and six of the seven viremic patients achieved suppression. One poorly adherent patient developed Q67K and K70H, conferring a roughly two-thousand-fold loss of susceptibility. With nine patients this is a case series, but it suggests limited viral evolution with adherence and high-level resistance without it.
We close with public health. In the BMJ, Wilson and colleagues describe the Ontario measles outbreak that contributed to Canada losing its elimination status [10]. Over 49 weeks there were 2,377 cases, and about nine in ten cases occurred in historically under-vaccinated communities, with limited spillover into the broader population. Nearly three quarters of cases were in people aged 19 or younger, and close to nine in ten cases were unvaccinated. There were 166 hospital admissions, 10 congenital infections, one case of encephalitis, and one infant death. Sequencing identified a novel strain later detected in the United States, Mexico, and the Netherlands. The authors argue that elimination is fragile where long-standing immunity gaps persist across interconnected communities, and that culturally appropriate engagement is central to closing them.
If you only have time for one paper this week, make it the cefepime-zidebactam study in Clinical Infectious Diseases [1]. It offers the first prospective clinical cure data for an agent targeting metallo-beta-lactamase producers in a population dominated by NDM, and reopens the question of what the preferred backbone for these infections should be.
Here is what this week's evidence adds up to in Infectious Disease. First, cefepime-zidebactam shows high cure rates in mostly urinary metallo-beta-lactamase infections, but single-arm data leave its comparative value unsettled, and a small cefiderocol cohort flags emergent resistance in NDM and OXA-48 co-producers. Second, the 2023 Duke criteria improve sensitivity at the cost of specificity without shrinking the possible endocarditis category, while the PACTO score now has external, though retrospective, support for risk-stratifying coagulase-negative staphylococcal bacteremia. Third, a randomized trial found antenatal STI screening did not reduce its composite birth outcome, with only a secondary signal for preterm birth after repeat screening. Fourth, minocycline plus metronidazole cures roughly four in five macrolide-resistant Mycoplasma genitalium infections, and doxycycline pre-treatment added no clear overall benefit. Fifth, measles re-establishment in a country with elimination status is no longer theoretical, and lenacapavir resistance in a tiny registry series appeared only alongside poor adherence.
That's your roundup for This Week in Infectious Disease. The full transcript and references are available on the episode page. This is an AI-curated summary — for clinical decisions, always consult primary sources and current guidelines. See you next week.
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