Quarterly Round-up of Notable Articles (March 2025–May 2025)
Year: 2025
Type: article
Abstract: THE FOURTH INTERNATIONAL CONSENSUS GUIDELINES ON THE MANAGEMENT OF CYTOMEGALOVIRUS IN SOLID ORGAN TRANSPLANTATION This article[1] represents the fourth update of international consensus guidelines on the management of cytomegalovirus (CMV) in solid organ transplant (SOT) recipients. The panel evaluated current research and clinical practices and used the GRADE system to rate the quality and strength of their recommendations. The article is structured into several thematic sections. Diagnostics The guidelines recommend CMV serologic testing (IgG only) for both donors and recipients prior to transplantation, forming the basis of risk stratification. High-risk patients are donor-positive/recipient-negative (D+/R–), while low-risk are D–/R–. The preferred diagnostic modality is CMV-quantitative nucleic acid amplification testing (QNAT), calibrated to the WHO standards, using either plasma or whole blood (but consistently one type per patient). The document discourages the use of CMV IgM testing and viral cultures for routine diagnosis. For tissue invasive disease, histopathology and immunohistochemistry remain the gold standards, supplemented by QNAT in specific tissues (e.g., bronchoalveolar lavage in lung transplants) Prevention The guidelines outline three core strategies for CMV prevention in SOT recipients: universal prophylaxis, preemptive therapy, and surveillance after prophylaxis (a hybrid approach). The choice depends on CMV serostatus, organ type, immunosuppressive intensity, and center resources. Universal prophylaxis This involves administering antivirals (typically valganciclovir) to all at-risk patients (those who have received lymphocyte-depleting antibodies, second signal inhibitors (e.g., belatacept), and other potent immunosuppression including desensitization or ABO-incompatible protocols (rituximab, bortezomib, eculizumab), and plasmapheresis and other desensitization agents starting within 10 days posttransplant. Letermovir, a newer option with fewer hematologic side effects, is recommended particularly for kidney recipients intolerant to ganciclovir. Valacyclovir may be used in kidney transplants where other options are unsuitable. Duration varies by organ and risk level: Kidney (D+/R–): 6 months Lung (D+/R–): 12 months Liver, pancreas, heart (D+/R–): 3–6 months R + recipients: Typically 3 months. Preemptive therapy This strategy monitors CMV DNA levels weekly and initiates treatment once a predefined threshold is reached. It is effective in preventing disease when minimizing drug exposure, resistance, and cost. However, it requires robust infrastructure and patient compliance. Lower thresholds are recommended for high-risk patients (D+/R–). Surveillance after prophylaxis Used mainly in high-risk patients, this approach resumes weekly monitoring after stopping prophylaxis (usually for 8–12 weeks) to detect late-onset CMV. Though not backed by trial data, many centers adopt it to catch delayed infections. Additional considerations mTOR inhibitors may reduce CMV risk and are an option for low-risk, seropositive recipients Secondary prophylaxis is reserved for select high-risk patients with prior CMV disease or profound immunosuppression For rejection treatment or intensified immunosuppression, prophylaxis is preferred due to higher CMV risk. Treatment For established CMV infection, the recommended antivirals include intravenous ganciclovir and oral valganciclovir. Treatment decisions are guided by viral load levels and kinetics. A change of ≥0.5 log10 IU/mL in DNAemia is considered clinically significant, and a majority of experts reported starting treatment for DNAemia at levels of 2–3.2 log10 IU/mL (100–1500 IU/mL) in plasma for D+/R– patients. The document emphasizes individualized thresholds for initiating therapy due to variability across assay platforms and specimen types. Resistance management is briefly touched upon, with references to alternative therapies for refractory cases. CMV-specific immune assay testing CMV-specific CMI assays can help resolve unclear serology, particularly in pediatric cases or after recent transfusions. While not yet standardized for routine use, CMI testing may guide decisions in ambiguous cases or in determining risk of recurrence. The guidelines also note emerging interest in RNA-based QNATs and neutralizing antibody assays, though these are not yet mainstream. Secondary prophylaxis and recurrence The authors address CMV recurrence posttreatment, particularly in high-risk patients. While secondary prophylaxis is not routinely recommended, it may be used in selected patients (e.g., those with high initial viral loads or augmented immunosuppression). The article discourages “mini-dose” valganciclovir due to concerns over subtherapeutic exposure and resistance development. Special populations and future directions Special recommendations are provided for thoracic organ transplants, pediatric recipients, and patients undergoing xenotransplantation. Future research priorities include harmonization of serologic assays, validation of CMV-CMI testing, and development of CMV diagnostic tools suitable for resource-limited settings. Comment These guidelines represent a comprehensive and timely update that addresses critical gaps in CMV management posttransplant. A major strength lies in their international, multidisciplinary authorship, and adherence to an evidence-based grading framework. The emphasis on assay standardization and viral load kinetics reflects a maturing understanding of CMV biology and its clinical implications. However, the breadth of the document may challenge practical implementation, particularly in resource-limited settings where access to commercial QNAT platforms and newer antivirals like letermovir is constrained. Moreover, the need for individualized thresholds due to assay variability undermines uniform clinical application, pointing to a persistent gap in diagnostic harmonization. Despite these limitations, the guidelines offer a well-structured, evidence-informed roadmap for improving CMV-related outcomes in transplant patients. COMPARATIVE EFFICACY AND SAFETY OF TREATMENT REGIMENS FORPNEUMOCYSTIS JIROVECII PNEUMONIA IN PEOPLE LIVING WITH HIV: A SYSTEMATIC REVIEW AND NETWORK META-ANALYSIS OF RANDOMIZED CONTROLLED TRIALS Methodology This study[2] presents a comprehensive systematic review and frequentist network meta-analysis (NMA) aimed at evaluating the efficacy and safety of various treatment regimens for Pneumocystisjirovecii pneumonia (PCP) in people living with HIV (PWH). The authors assessed data from 14 randomized controlled trials (RCTs) conducted between 1983 and 1996, involving 1788 patients and 27 treatment arms. Objectives and scope The primary aim was to determine which treatment regimens offer the best combination of treatment efficacy (measured by failure and mortality) and tolerability (measured by treatment discontinuation due to toxicity). The authors also sought to identify alternatives to the standard first-line drug, trimethoprim–sulfamethoxazole (TMP-SMX), which is associated with high rates of adverse effects. RCTs comparing at least two PCP treatment regimens in adult HIV-positive individuals were included. The study followed PRISMA and Cochrane Handbook guidelines. Excluded were pediatric studies, noncomparative trials, and studies on prophylaxis or corticosteroids. Efficacy analysis – Treatment failure Direct comparisons: TMP-SMX was significantly more effective than atovaquone and trimetrexate/leucovorin. Network rankings (surface under the cumulative ranking curve analysis [SUCRA]): Clindamycin/primaquine, IV pentamidine, and TMP-SMX each scored 0.8, with clindamycin/primaquine ranked highest based on probability (34.6%). Efficacy analysis – All-cause mortality Direct comparison: TMP-SMX showed lower mortality than atovaquone Network rankings Dapsone + TMP ranked highest for reducing mortality (SUCRA: 0.8; 37.6% probability) IV pentamidine closely followed TMP-SMX remained among the top contenders but showed no definitive superiority in the network. Safety and tolerability Toxicity risk: TMP-SMX was consistently associated with the highest toxicity Direct comparisons: Significant improvements in tolerability were seen with dapsone + TMP, atovaquone, and inhaled pentamidine Network rankings Inhaled pentamidine was the best tolerated (SUCRA: 0.9) Followed by trimetrexate/folinic acid and atovaquone TMP-SMX ranked lowest. Subgroup and sensitivity analyses No significant differences emerged in sensitivity testing Subgroup analysis by severity was not feasible due to inconsistent reporting Bias risk was moderate; about half the trials were open-label All studies predate widespread antiretroviral therapy (ART) and included primarily young, white, male patients, limiting generalizability to modern, diverse populations. Comment This article represents a methodologically robust and clinically valuable contribution to the optimization of PCP treatment in HIV-positive individuals. By applying a network meta-analytic approach, the authors have successfully ranked available treatment options based on both efficacy and tolerability, a practical innovation over traditional pairwise meta-analyses. The most striking finding is the lack of clear overall superiority of TMP-SMX, long regarded as the standard of care. While it remains most effective, its inferior safety profile is significant. This insight calls for a reappraisal of its universal first-line status, particularly in patients with renal insufficiency, hypersensitivity, or other risk factors for toxicity. The rankings provide a nuanced picture. Clindamycin/primaquine and IV pentamidine emerge as strong alternatives for efficacy, while inhaled pentamidine and atovaquone offer better safety. Such information empowers clinicians to tailor treatments according to individual patient needs, especially in complex or high-risk cases. Note on surface under the cumulative ranking curve analysis rankings versus actual efficacy While actual effectiveness is measured by outcomes like treatment failure in head-to-head comparisons (e.g., TMP-SMX being better than atovaquone), SUCRA rankings estimate how likely each treatment is to be the best overall across all studies. So, a drug like clindamycin/primaquine may rank highest (34.6% chance) even if it hasn’t clearly outperformed others in direct trials. Thus, probability rankings guide relative positioning but do not replace clinical effect estimates. The limitations of the study are as follows: All data are drawn from older studies (pre-1996), lacking modern ART-era context Demographic homogeneity (predominantly white, male, and North American populations) undermines global applicability Low-dose TMP-SMX was not evaluated in any trials, despite increasing observational evidence indicating it may offer comparable efficacy with fewer side effects. Treatment duration (21 days) remains arbitrary and based on limited historical data Corticosteroid usage would skew the outcomes as well. The article rightly calls for modern RCTs that reflect today’s HIV treatment standards and include underrepresented groups. Until such data become available, the current NMA provides the best comparative evidence to support more personalized, flexible, and safer treatment approaches for PCP in PWH. RECENT EMERGENCE OF CEPHALOSPORIN-RESISTANTSALMONELLA TYPHIIN INDIA DUE TO THE ENDEMIC CLONE ACQUIRING INCFIB (K) PLASMID ENCODING BLACTX-M-15 GENE Methodology This study[3] examined 142 Salmonellatyphi isolates from febrile patients in Gujarat, India (2022–2023), to investigate rising cephalosporin resistance. Antimicrobial susceptibility testing confirmed that nearly all isolates were resistant to ceftriaxone, ciprofloxacin, ampicillin, and co-trimoxazole. Whole-genome sequencing was performed using Illumina and Oxford Nanopore platforms. Genotyping identified a novel subclade (4.3.1.2.2) within H58 lineage II. Most isolates (140/142) formed a tight phylogenetic cluster, indicating recent clonal spread. Resistance genes, including the blaCTX-M-15 gene, were located on an IncFIB(K) plasmid that also carried several other resistance determinants. Plasmid stability assays confirmed long-term retention even without antibiotic pressure. Comparative analysis showed similarity to resistance plasmids in Escherichiacoli and Shigella, suggesting horizontal gene transfer. Comment This study provides compelling genomic evidence of a rapidly emerging threat: the local clonal expansion of a cephalosporin-resistant S. typhi strain in India. The detection of the blaCTX-M-15 gene on a stable IncFIB (K) plasmid within a newly defined subclade (genotype 4.3.1.2.2) marks a significant shift in the antimicrobial resistance profile of S. typhi, particularly within the previously less plasmid-prone H58 lineage II. One of the study’s major strengths lies in its integration of high-resolution genomic tools, combining short-read and long-read sequencing for accurate identification of plasmid structures and resistance genes. The use of SNP-based phylogenetics, plasmid stability assays, and comparative plasmid genomics offers a thorough and multiangle characterization of the resistant clone. The findings challenge previous assumptions that lineage II of H58 was less likely to acquire or retain large resistance plasmids due to fitness costs. The observed high plasmid stability, even in the absence of antibiotic pressure, suggests that under the right selective conditions, such as high antibiotic usage, S. typhi can overcome those limitations. This positions India on a potentially similar trajectory to Pakistan’s XDR typhoid outbreak, where cephalosporin resistance rapidly became endemic. The study, however, has some constraints. Its geographic focus is limited to Gujarat, and without clinical outcome data (e.g., treatment failure or hospitalization rates), the direct impact of resistance on patients remains unclear. In addition, while the plasmid’s similarity to those found in E. coli and Shigella points to horizontal gene transfer, the absence of donor strain identification makes the exact transmission pathway speculative. Despite these limitations, the study’s implications are significant. It highlights the need for immediate public health responses, including national scale-up of typhoid conjugate vaccines and enhanced genomic surveillance. If not addressed early, this resistant clone could compromise the remaining oral treatment options and trigger a new wave of difficult-to-treat typhoid in India. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.
Author: Sujata Rege
Language: English
Subfield: Epidemiology
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
OpenAlex ID: W4411713656