Comparative Bactericidal Activity Of Representative ß-Lactams Against Enterobacterales, Acinetobacter Baumannii and Pseudomonas Aeruginosa

[Posted 25/May/2022]

AUDIENCE: Infectious Disease, Internal Medicine

KEY FINDINGS: ß-Lactam sub-classes (penicillins, cephalosporins, monobactams and carbapenems) have different antibacterial effects against E. coli, K. pneumoniae, A. baumannii and P. aeruginosa. Extrapolation of in vitro pharmacodynamic findings from one species to another or one sub-class of ß-lactam to another is not justified.

BACKGROUND: There is surprisingly little comparative published data on the bactericidal action of different sub-classes of ß-lactams against aerobic Gram-negative rods, and the assumption is that all behave in the same way. Purpose of this study is to describe a systematic investigation of a representative penicillin, cephalosporin, monobactam and carbapenem against Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa.

DETAILS: Concentration-time-kill curves (TKC) were determined for three strains each of E. coli, K. pneumoniae, A. baumannii and P. aeruginosa. All strains were susceptible to the agents used. The antibiotics were piperacillin/tazobactam, ceftazidime, aztreonam and meropenem. The initial inoculum was 106 cfu/mL and TKC were determined over 48 h. The area-under-the-bacterial-kill curve to 24 h (AUBKC 24 log cfu.h/mL) and 48 h (AUBKC 48) were used to measure antibacterial effect (ABE). Population profiles before and after antibiotic exposure were recorded. Against E. coli and K. pneumoniae meropenem had a maximal ABE at >=MIC x 1 concentrations while piperacillin/tazobactam and ceftazidime had maximal effect at >=MIC x 4 and aztreonam at >=MIC x 8 concentrations. Ceftazidime, aztreonam and meropenem had less ABE against K. pneumoniae than E. coli. Against P. aeruginosa, meropenem was most bactericidal, with a maximum ABE at 8x/16 x MIC. Other ß-lactams had notably less ABE. In contrast, against A. baumannii, ceftazidime and meropenem had the greatest ABE, with a maximal effect at >=MIC x 4, concentration changes in population profiles were least apparent with E. coli.

Copyright © Oxford University Press. All rights reserved.

Source: Noel, A. R., Attwood, M., Bowker, K. E., et al. (2022). Comparative Bactericidal Activity Of Representative ß-Lactams Against Enterobacterales, Acinetobacter Baumannii and Pseudomonas Aeruginosa. Journal of Antimicrobial Chemotherapy. 2022; 77(5): 1306-1312. Published: May, 2022. DOI: 10.1093/jac/dkac026.

[Posted 15/Jun/2026]

AUDIENCE: Infectious Disease, Internal Medicine

KEY FINDINGS: Study results suggest that clinicians should initiate antiviral chemoprophylaxis for at least 70% of eligible NH residents within 2 days of outbreak detection to lower risk of hospitalization.

BACKGROUND: Influenza outbreaks in nursing homes (NHs) pose a substantial threat to older adults, often resulting in morbidity and mortality. The Centers for Disease Control and Prevention (CDC) and the Infectious Diseases Society of America (IDSA) recommend prompt postexposure prophylaxis, also termed chemoprophylaxis or prophylaxis with oseltamivir, for all residents who are not ill to limit influenza spread in NHs. Purpose of the study is to examine whether initiating antiviral chemoprophylaxis for 70% or more of eligible NH residents within 2 days of influenza outbreak detection is associated with lower all-cause mortality and hospitalization at 14 and 30 days.

DETAILS: Retrospective cohort study using a sequential cluster-randomized target trial emulation and randomize-censor-weight approach for influenza outbreaks (September 1, 2018-May 31, 2022) in 12 US NH corporations. Eligibility criteria were age 18 years or older, present on the outbreak-detection day, no antiviral use in the preceding 7 days, no influenza in the past 14 days, and complete baseline data. Residents were followed up until hospitalization or death, an NH discharge to a nonacute-care location, or the end of follow-up. Data were analyzed from February 2023 to January 2026.

Exposures: Intensive antiviral chemoprophylaxis with oseltamivir (>=70% of eligible residents within 2 days of outbreak detection) or nonintensive antiviral chemoprophylaxis (0% to <70% of eligible residents).

Outcomes were all-cause death and hospitalizations within 14 and 30 days of outbreak detection. Discrete-time hazard models with pooled logistic regression were applied to estimate weighted risks, risk differences (RDs), and risk ratios (RRs).

Among 404 outbreaks in 318 NHs, 35,086 resident-trial observations (29,683 residents; median age 78 [IQR, 68- 86] years; 60% women; 81% White; 76% vaccinated) met eligibility criteria. Intensive oseltamivir prophylaxis was randomized to 17,155 observations; 17,931 were randomized to nonintensive care. At 14 days, intensive prophylaxis vs nonintensive yielded an RD of -0.06% (95% CI, -0.73% to 0.93%) and an RR of 0.96 (95% CI, 0.56-1.57) for death, and an RD of -0.96% (95% CI, -1.78% to -0.19%) and an RR of 0.79 (95% CI, 0.64-0.96) for hospitalization. At 30 days, the hospitalization differences persisted but were less precise and there continued to be no difference in death.

Copyright © American Medical Association. All Rights Reserved.

Source: Silva, J. B. B., Hsieh, H. T., Howe, C. J., et al. Prompt and Intensive Antiviral Chemoprophylaxis in Nursing Home Influenza Outbreaks. JAMA Internal Medicine.. 2026; 186(6): 714-722. Published: June, 2026. DOI: 10.1001/jamainternmed.2026.0401

A Randomized Controlled Comparative Study

[Posted 19/May/2026]

AUDIENCE: General Surgery, Family Medicine

KEY FINDINGS: Early active treatment with isotretinoin and FMRF is safe and better than isotretinoin monotherapy over 44 weeks regarding severity, reduced erythema, and improved surface roughness in moderate-to-severe acne vulgaris. This encourages early and effective treatment of acne to mitigate acne scarring and improve patients' quality of life.

BACKGROUND: Oral isotretinoin is the standard therapy for severe acne. However, scarring may persist. Fractional microneedling radiofrequency (FMRF) improves both inflammatory lesions and scars with minimal downtime. In this study, we compare isotretinoin monotherapy and concurrent isotretinoin and FMRF for active acne regarding clinical outcomes. The GAGS scores of isotretinoin and FMRF were significantly lower than those of isotretinoin monotherapy from weeks 12-44 (-79.69% vs. -60.34% at week 44, respectively; p < 0.001). Isotretinoin and FMRF showed significantly greater lesion count reductions than isotretinoin monotherapy at follow-up visits from weeks 12-44. Isotretinoin and FMRF showed significantly lower hemoglobin levels than isotretinoin monotherapy at weeks 32 and 44 (p = 0.029 and p < 0.001, respectively). Skin surface roughness improved substantially and persistently from week 12-44.

DETAILS: In this parallel two-group comparative study, patients received either low-dose isotretinoin monotherapy for 20 weeks (n = 34) or low-dose isotretinoin concurrently with 5 monthly FMRF sessions (n = 36). Outcomes were assessed at baseline and weeks 12, 20, 24, 32, and 44. The primary endpoints were Global Acne Grading System (GAGS) scores and inflammatory/non-inflammatory lesion counts. Secondary endpoints were hemoglobin indices and skin roughness.

Copyright © Wiley Periodicals LLC. All rights reserved

Source: Disphanurat, W., Leeyangyuen, P,, and Srisantithum, B. Efficacy of Low-Dose Oral Isotretinoin Combined With Fractional Microneedle Radiofrequency Versus Low-Dose Oral Isotretinoin Monotherapy in the Treatment of Moderate-To-Severe Acne Vulgaris: A Randomized Controlled Comparative Study. Lasers in Surgery and Medicine. 2026; 58(4): 321-330. Published: April, 2026. DOI: 10.1002/lsm.70120.

A Case Report

[Posted 2/Mar/2026]

AUDIENCE: General Surgery, Infectious Disease

KEY FINDINGS: PDT mediated by MB is an effective and affordable approach for treating FEH associated with HPV in immunosuppressed patients, offering favorable outcomes and improved quality of life.

BACKGROUND: Human papillomavirus (HPV) infections are a major cause of oral lesions, and in individuals living with HIV, lesions such as focal epithelial hyperplasia (FEH) may persist or exhibit atypical features, potentially progressing to more severe conditions if untreated. Managing oral HPV lesions in immunocompromised patients is challenging, as conventional therapies may carry higher risks or show limited efficacy.

DETAILS: This study reports the case of a 49-year-old HIV-positive male with valve disease and arthritis, requiring crutches for mobility. He presented with multiple painless oral lesions, diagnosed as FEH associated with oral HPV, and had previously undergone unsuccessful treatments. Photodynamic therapy (PDT) using methylene blue (MB) and a red laser was proposed as a treatment. Topical MB-mediated PDT successfully cleared the FEH lesions, with no recurrence observed over 24 months.

Copyright © Wiley Periodicals LLC. All rights reserved

Source: de Araújo, J. C., Paiva, H. C., Faara, P. M. M., et al. Long-Term Control of Human Papillomavirus-Related Focal Epithelial Hyperplasia in an Human Immunodeficiency Virus-Positive Patient Using Methylene Blue-Mediated Photodynamic Therapy. A Case Report. Lasers in Surgery and Medicine. 2026; 58(2): 70-73. Published: February, 2026. DOI: 10.1002/lsm.70091

[Posted 15/Dec/2025]

AUDIENCE: Gastroenterology, Infectious Disease

KEY FINDINGS:

• Vote Margin: The ACIP voted 8-3 to end the universal HepB birth dose recommendation.
• New Guidance: Vaccination at birth is recommended only for infants of mothers who are positive for HepB or have unknown status.
• Negative Mothers: Mothers who test negative are advised to consult their healthcare provider to decide the timing of their child's vaccination.
• Policy Impact: A change in the recommendation, if approved by the CDC Director, could affect state policies and private insurance coverage of the vaccine.

BACKGROUND: The Hepatitis B (HepB) vaccine has historically been universally recommended for all infants at birth by the Centers for Disease Control and Prevention's Advisory Committee on Immunization Practices (ACIP). This policy ensures protection against perinatal transmission and helps reduce the overall disease burden.

DETAILS: The CDC's Advisory Committee on Immunization Practices (ACIP) recently held a vote to reconsider the universal recommendation for the HepB vaccine at birth. The panel voted by a margin of 8-3 to cease the blanket recommendation that all infants receive the vaccine at birth. The new guidance maintains the recommendation only for infants whose mothers test positive for the infection or have unknown status. Mothers who test negative for Hepatitis B would be advised to "talk with their healthcare provider and decide themselves when to vaccinate their child." The discussion involved controversy, including a newly appointed ACIP member without medical training who reportedly argued against the universal birth dose, claiming vaccines had "never tested (the vaccines) appropriately." Dr. Cody Meissner, the sole continuing ACIP member, criticized the proposed change, stating "no rational science [had] been presented" to justify it. The ACIP voted in favor of changing the recommendations. These recommendations must now go to the CDC director for approval. While states ultimately set their own immunization policies, they generally rely on CDC guidelines. A change in ACIP recommendations can also influence insurance coverage, as most private insurers are required to cover recommended vaccines.

Reference: MacKenzie, M. ACIP Votes to End Hepatitis B Vaccine Recommendation for All Newborns. Healthcare Purchasing News. 2025; Published: December 6, 2025.

[Posted 28/Aug/2025]

AUDIENCE: Neurology, Pediatric, Neurosurgery

KEY FINDINGS: Infants up to 6 weeks of age with genetically diagnosed SMA who were treated with risdiplam before the development of clinical signs or symptoms appeared to have better functional and survival outcomes at 12 and 24 months than untreated infants in natural history studies. Larger, controlled studies with longer follow-up are needed to further understand the relative efficacy and safety of presymptomatic treatment of SMA with risdiplam.

BACKGROUND: Risdiplam, an oral pre–messenger RNA splicing modifier, is an efficacious treatment for persons with symptomatic spinal muscular atrophy (SMA). The safety and efficacy of risdiplam in presymptomatic disease are unclear.

DETAILS: Authors conducted an open-label study of daily oral risdiplam (with the dose adjusted to 0.2 mg per kilogram of body weight) in infants 1 day (birth) to 42 days of age with genetically diagnosed SMA but without strongly suggestive clinical signs or symptoms. The primary outcome, assessed in infants with two SMN2 copies and a baseline ulnar compound muscle action potential (CMAP) amplitude of at least 1.5 mV, was the ability to sit without support at month 12. Natural history studies have shown that the majority of infants with two SMN2 copies who are untreated would have a severe SMA phenotype (type 1), would never sit independently, would receive permanent ventilation and feeding support, or would die by 13 months of age. Secondary outcomes that were assessed over a period of 24 months included survival, ventilatory support, motor milestones, the development of clinically manifested SMA, feeding, and growth. A total of 26 infants with two, three, or four or more copies of SMN2 were enrolled. After 12 months of treatment, 21 infants (81%) could sit unsupported for 30 seconds, 14 (54%) could stand alone, and 11 (42%) could walk alone. A total of 4 of 5 infants (80%; 95% confidence interval, 28 to 100) with two SMN2 copies and a baseline ulnar CMAP amplitude of at least 1.5 mV were able to sit without support for at least 5 seconds. Three infants were withdrawn from the study by a parent or caregiver after the month 12 visit. Of 23 infants who completed 24 months of treatment, all were alive without the use of permanent ventilation or feeding support. Over a period of 24 months, nine treatment-related adverse events were reported in 7 infants; none of these events were serious.

Copyright © Massachusetts Medical Society. All rights reserved.

Source: Finkel, R. S., Servais, L., Vlodavets, D., et al. (2024). Risdiplam in Presymptomatic Spinal Muscular Atrophy. N Engl J Med. 2025; 393(7): 671-682. Published: August 13, 2025. DOI: 10.1056/NEJMoa2410120.