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European Journal of Clinical Microbiology & Infectious Diseases

○ Springer Science and Business Media LLC

Preprints posted in the last 30 days, ranked by how well they match European Journal of Clinical Microbiology & Infectious Diseases's content profile, based on 15 papers previously published here. The average preprint has a 0.01% match score for this journal, so anything above that is already an above-average fit.

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Rapid Phenotypic Antibiotic Susceptibility Determination Direct From Spiked Urine Samples Shows Strong Correlation with Gold Standard for Urinary Tract Infection

Roegner, M.; Ahmadi, C.; Lyon, S.; McGee, Z.; Chittur, K.; Millirons, P.

2026-09-23 microbiology 10.64898/2026.09.21.753156 medRxiv
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GeneCapture is developing a novel, point-of-care, rapid AST technique that, when fully automated, can accomplish AST within 2 hours directly from a raw sample, representing a significant advancement in diagnostic capabilities. For this study, a panel of uropathogen isolates was collected from clinical specimens positive for urinary tract infection from various laboratories in the southern US. A selection of these isolates were then spiked into fresh clean-catch urine samples to produce mock samples covering a variety of antibiotic responses. Testing was performed on 20 strains of Escherichia coli, the cause of over 80% of UTIs, and 6 strains each of Klebsiella pneumoniae and Proteus mirabilis, the next most common causes. Each strain was tested against the susceptible, intermediate and resistant (S-I-R) breakpoints of up to 5 appropriate antibiotics including Amoxicillin-Clavulanate, Cefpodoxime, Ciprofloxacin, Nitrofurantoin and Trimethoprim-Sulfamethoxazole. The new method uses a phenotypic assessment of bacterial growth, comparing responses from bacteria treated with antibiotics at S-I-R breakpoint concentrations to untreated controls as the metric for determining susceptibility. Exposure to the drugs for only 90 minutes gave a Categorical Agreement of 98% to gold standard culture results across the resulting 247 bacteria/antibiotic pairs. Testing on separate days of nine of these strains in triplicate gave a reproducibility of 97%. The sequential steps of this novel AST - sample processing, growth, labeling, and counting - can readily be performed on an automated cartridge that is currently under development. The presented work, which took place in a laboratory setting, demonstrates the efficacy of the assay.

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Clinicians Perspectives on Fighting the Ventilator

Olivier, L.; Madzhakova, D.; Lauterbach Oprea, C.; Stollenwerk, A.; Orlikowsky, T.; Schoberer, M.

2026-10-21 pediatrics 10.64898/2026.10.20.26365990 medRxiv
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Introduction: Fighting the ventilator (FV) is characterized by a patients active counteraction of respiratory gas flow across multiple breaths during mechanical ventilation. An effective ventilation is prevented during such episodes. The objective of this exploratory study was to evaluate clinicians knowledge, perception and agreement regarding this condition. Methods: In a cross-sectional online survey, medical professionals with experience in intensive care medicine (mostly neonatal and pediatric patients) responded to 11 questions covering various clinical aspects of FV. Results: All respondents were familiar with the phenomenon and assessed it to be clinically relevant. Neonates were perceived to be predominantly affected. Promoting factors of FV included inadequate sedation and ventilation-associated factors. In clinical practice, the participants identified FV by clinical evaluation, analysis of ventilator waveforms and capnography and used both pharmacological and non-pharmacological intervention strategies. There was no consensus concerning the English terminology of the condition. Only few respondents were familiar with local guidelines to manage FV. Conclusion: Although there was consensus on the relevance of FV, diagnostics and management strategies were highly heterogeneous. Many participants agreed that poor patient-ventilator synchrony was an important cause of FV. Future work should focus on characterizing and generating evidence on FV.

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Validation of an electronic-nose sensor array in detecting C. difficile and differentiating toxin-positive from toxin-negative stool samples

Balius, P. N.; Campbell, C.; Ikrma, M.; Nguyen, H. H.

2026-10-08 infectious diseases 10.64898/2026.10.06.26364614 medRxiv
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Objective: To evaluate the specimen-level performance of a multichannel electronic nose (e-nose) sensor array in classifying stool specimens into relevant Clostridioides difficile categories. Design: Retrospective single-center validation study with reference to polymerase chain reaction (PCR) and C. difficile toxin testing. Participants: A convenience sample of 31 discarded stool specimens with PCR and confirmatory toxin testing. Categorized into PCR-positive (+)/toxin+, PCR+/toxin-negative (-), and PCR-. Methods: Specimens were sampled in controlled headspace by two e-nose sensor arrays in 10-minute sessions with 5-second sampling intervals. The primary endpoint was one-versus rest classification performance (sensitivity, specificity, positive predictive value, and accuracy) into three classes: PCR+/toxin+, PCR+/toxin-, and PCR-. Data were normalized and the region of interest was extracted for training and testing. Random forests were utilized for classification of normalized data with a test-train split at the specimen-level. Results: There were 457 unique 10-minute sampling events (147 PCR+/toxin+, 183 PCR+/toxin-, 127 PCR-). Sensors 1 and 2 captured 20,331 and 23,538 unique 5-second exposures within the region of interest, respectively. Testing data classification accuracy was 0.79 [0.78, 0.81] and 0.84 [0.83, 0.85] for Sensors 1 and 2. Sensitivity for PCR+/toxin+ exposures was 0.82 [0.79, 0.84] and 0.94 [0.92, 0.95], and specificity was 0.91[0.90, 0.93] and 0.93 [0.92, 0.94] for Sensors 1 and 2. Conclusion: An e-nose sensor array partially differentiated PCR-classified C. difficile specimen classes at the exposure level under headspace-controlled conditions. Performance was strongest for PCR+/toxin+ exposures. Findings support further prospective validation in the hospital room setting.

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Development and validation of a laboratory-developed test on Panther Fusion(R) system for detection of macrolide resistance in Bordetella pertussis

Sadeesh Kumar, L.; Sait, M.; Howden, B. P.; Sherry, N. L.

2026-09-25 infectious diseases 10.64898/2026.09.22.26363724 medRxiv
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Macrolides remain the first-line antimicrobial treatment for pertussis, primarily caused by Bordetella pertussis. Emergence of macrolide-resistant B. pertussis in Australia and globally presents a growing concern for clinical management. As molecular diagnosis predominates for pertussis, limited numbers of cultures are available for antimicrobial susceptibility testing. The A2037G mutation in the 23S rRNA gene is most commonly associated with macrolide resistance in B. pertussis, yet no commercial molecular assay is available for its detection. In this study, we adapted and validated a previously published real-time PCR assay as a laboratory developed test (LDT) on the Panther Fusion(R) system using Open Access functionality to detect the macrolide resistance-associated mutation in B. pertussis from culture isolates and clinical specimens. Total turnaround time was ~2.5 h for the first result and 2-3 min for subsequent results in the same batch, with an estimated cost of AUD 18 per sample, excluding labour. A total of 30 samples were included in the validation panel to assess assay performance. All isolates and clinical specimens in the validation panel produced results concordant with the expected mutation status, demonstrating 100% accuracy, sensitivity and specificity. The assay demonstrated a limit of detection of 1.5 x 103 CFU/mL (22 CFU/reaction). This Panther Fusion(R) LDT provides a rapid and fully automated approach for molecular detection of the targeted mutation associated with macrolide resistance in B. pertussis. Its integration into routine molecular workflows as a reflex test following identification of B. pertussis may facilitate timely identification of resistant infections.

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Oxazolidinone antibiotics exhibit potent in vitro activity against Gram-positive bacterial endophthalmitis isolates

Rahim, M. G.; Young, E. A.; Romanowski, E. G.; Eller, A. W.; Shanks, R. M. Q.

2026-10-06 microbiology 10.64898/2026.10.05.756736 medRxiv
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Purpose: Vancomycin-resistant Gram-positive organisms represent a potential therapeutic challenge in endophthalmitis. To evaluate alternative treatment options, the FDA-approved oxazolidinones linezolid (LZD) and tedizolid (TZD) were tested against a collection of Gram-positive bacterial endophthalmitis isolates. Methods: Minimum inhibitory concentrations (MICs) were determined using epsilometers (Etest strips) for coagulase negative staphylococci (CoNS, n=20), Staphylococcus aureus (n=18), Bacillus species (n=10), Enterococcus species (n=5), and Streptococcus pneumoniae (n=1). Available CLSI and EUCAST breakpoints were applied to determine susceptibility. Results: TZD exhibited a >5-fold reduction in median MIC compared with LZD across all organisms tested (p<0.0001). MIC90 values for CoNS were 2.0 /ml for LZD and 0.25 /ml for TZD. For S. aureus, MIC90 values were 1.5 /ml (LZD) and 0.19 /ml (TZD). For Bacillus spp., MIC90 values were 1.0 /ml (LZD) and 0.25 /ml (TZD). Among Enterococcus species, the MIC range was 0.5-4.0 /ml (LZD) and 0.064-0.75 /ml (TDZ). The single S. pneumoniae strain had a MIC of 0.5 for LZD and 0.064 for TZD. All isolates were susceptible to TZD. One Enterococcus isolate was non-susceptible to LZD; the remaining isolates were susceptible. Conclusions: LZD and TZD demonstrated in vitro activity against Gram-positive bacterial endophthalmitis isolates, with TZD displaying consistently lower MICs than LZD. These findings suggest that oxazolidinones may represent potential alternatives when vancomycin cannot be used, including infections caused by vancomycin-resistant Gram-positive organisms. Given their excellent oral bioavailability, favorable safety profile, and reported anti-virulence effects in certain pathogens, further evaluation of oxazolidinones for the treatment of intraocular infections is warranted.

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Age-Stratified Patterns of Diagnostic Delay in Pertussis

Serman, E. A.; Jayawardena, I.; Liskey, C.; LaCroix, R.; Litwin, A. H.; Obeid, J. S.; Curry, S. R.; Rennert, L.

2026-10-01 epidemiology 10.64898/2026.09.25.26364016 medRxiv
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Background: Pertussis has resurged in the post-COVID-19 era, yet diagnostic delay remains a barrier to timely treatment and transmission interruption, particularly among adults. Methods: Retrospective observational cohort study of 787 patients with confirmed pertussis from January 2016 through March 2026 across two South Carolina health systems. Electronic health record data from the 60 days preceding confirmation were used to characterize diagnostic timing (same-day vs. delayed), delay duration, and respiratory pathogen testing patterns including pertussis test modality. Results: Adults accounted for 48.4% of cases (median age 16 years [IQR 4-52]; 61.6% female). Same-day diagnosis was highest among children aged 1-4 years (75.4%) and lowest among adults aged 50 and older (approximately 50%). Among the 305 patients (38.8%) with delayed diagnosis, median delay ranged from 7-12 days in children to 22.5-26.5 days in adults aged 50 and older. Delay did not vary significantly by COVID-19 period, race, ethnicity, or insurance type. Testing breadth was greater in inpatient and emergency settings than outpatient. Pertussis testing was predominantly PCR-based in children but serologic in adults, potentially reflecting later clinical presentation relative to illness onset; however, the near-absence of PCR testing in older adults may contribute to missed diagnoses during the early illness window when PCR sensitivity is highest. Conclusions: Older adults experienced markedly delayed pertussis diagnoses compared with children. Earlier consideration of pertussis in adults with prolonged cough, including PCR testing early in illness before serologic conversion, may reduce diagnostic delay and facilitate timelier treatment and contact tracing.

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Antimicrobial Resistance Patterns Of Bacterial Isolates From Neonates With Sepsis At Livingstone University Teaching Hospital, Zambia

Siaciti, L.; Siacit, M.; SIMUTANDA, C.; Tembo, N. N.

2026-09-29 pediatrics 10.64898/2026.09.27.26364139 medRxiv
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Background Neonatal sepsis remains a major cause of neonatal morbidity and mortality, particularly in low- and middle-income countries. Its management is increasingly complicated by antimicrobial resistance (AMR), while limited facility-specific data on causative bacterial pathogens and susceptibility patterns often necessitate empirical antibiotic treatment. This study assessed the prevalence of neonatal sepsis, bacterial pathogens and antimicrobial resistance patterns, and maternal, neonatal and clinical factors associated with neonatal sepsis among neonates admitted to the Neonatal Intensive Care Unit (NICU) at Livingstone University Teaching Hospital (LUTH), Zambia. Methods A retrospective cross-sectional record review was conducted among neonates admitted to the NICU at LUTH from 2020 to 2025. A total of 150 neonatal records were analysed. Neonatal, maternal, clinical, blood culture and antimicrobial susceptibility data were analysed using descriptive statistics, chi-square tests and logistic regression. Missing information was treated as missing and was not imputed; denominators were reported according to the records available for each analysis. Results Neonatal sepsis was identified in 52/150 neonates, giving a prevalence of 34.7% (95% CI: 27.5%-42.6%). Among the 52 sepsis cases, 20 had positive blood cultures, corresponding to a culture positivity rate of 38.5% (95% CI: 26.5%-52.0%); this represented 13.3% of the full study sample. Maternal fever during labour (aOR=6.822; 95% CI: 2.032-22.905; p=0.002) and caesarean delivery (aOR=2.245; 95% CI: 1.050-4.801; p=0.037) were independently associated with neonatal sepsis, while increasing birth weight was protective (aOR=0.891 per 100 g; 95% CI: 0.817-0.973; p=0.010). Escherichia coli was the most frequent isolate (5/20; 25.0%), followed by Klebsiella pneumoniae (4/20; 20.0%) and Staphylococcus aureus (4/20; 20.0%). Resistance was highest to ampicillin (15/19; 78.9%), followed by gentamicin and ceftriaxone (10/19; 52.6% each), while all 19 isolates tested against meropenem were susceptible. Conclusion The findings indicate that empirical management of neonatal sepsis at LUTH should be informed by local microbiological surveillance rather than reliance on historical first-line susceptibility assumptions. Routine blood culture and susceptibility testing, a regularly updated facility antibiogram, strengthened infection prevention and antimicrobial stewardship are required to improve treatment decisions and preserve effective antibiotics. Interpretation should consider the retrospective single-centre design, incomplete routine records and the small number of culture-positive isolates.

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Enhancing molecular and genomic approaches for Bordetella pertussis investigation and public health surveillance in Victoria, Australia

Sadeesh Kumar, L.; Sait, M.; Fachrul, M.; Judd, L. M.; Lacey, J. A.; Strachan, J.; Baines, S. L.; Howden, B. P.; Sherry, N. L.

2026-10-13 infectious diseases 10.64898/2026.10.11.26364704 medRxiv
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Bordetella pertussis is the main aetiological agent of pertussis (whooping cough), with a global resurgence of cases reported in 2024. As current pertussis diagnostics are predominantly based on molecular methods, cultured isolates are increasingly scarce, limiting traditional culture-based surveillance. To address these challenges, this study evaluated culture-independent approaches for B. pertussis surveillance and their feasibility for implementation in public health laboratory settings in Victoria, Australia. The Microbiological Diagnostic Unit Public Health Laboratory received 356 nasopharyngeal clinical specimens that were PCR-positive for Bordetella spp. from diagnostic laboratories for further characterisation during the 2024-2025 epidemic period. Culture-based approaches yielded only five B. pertussis isolates, largely due to limitations associated with specimen transport media. Four culture-independent approaches were evaluated for B. pertussis characterisation: real-time PCR assay for high-resolution Bordetella spp. differentiation (n=356), multiplex PCR amplicon sequencing assay for lineage typing (n=38), in-house laboratory developed test implemented on Panther Fusion(R) System for macrolide resistance screening (n=92) and shotgun metagenomic sequencing (n=5). The dataset was dominated by B. pertussis (330/356; 92.7%) with most strains harbouring ptxP3 (35/38; 92.1%) allele and the macrolide resistance rate was reported as 4.3% (4/92). Shotgun metagenomics was able to detect B. pertussis directly from clinical samples, but the genomic recovery was limited. Evaluation of operational performance and workflow integration highlighted method-specific strengths and limitations, informing suitability for implementation in public health laboratories. This study demonstrates the potential to integrate culture-independent approaches into public health laboratory settings to strengthen B. pertussis surveillance and inform feasible workflow design amid limited culture availability.

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Genomic Epidemiology and Genetic Relatedness of Antimicrobial-Resistant Morganella morganii in Community and Hospital Settings in Bangladesh

Rahman, T.; Khan, T.; Haider, A.; Moon, S. B.; Samia, N. S. N.; Mah-E-Muneer, S.; Mamun, G. M. S.; Chowdhury, F.; Rahman, M.; Jubair, M.

2026-09-29 infectious diseases 10.64898/2026.09.23.26363554 medRxiv
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Morganella morganii is an opportunistic pathogen with intrinsic and acquired antimicrobial resistance, but its genomic epidemiology remains poorly characterized in Bangladesh. We sequenced and compared genomes of 47 stool-derived M. morganii isolates from hospital (n = 29) and community (n = 18) participants in urban Dhaka. Susceptibility testing showed frequent resistance to imipenem (70.2%) and cefuroxime (97.9%), while all isolates were resistant to colistin. Resistance to meropenem (6.4%) and ertapenem (2.1%) was uncommon. Based on acquired non-susceptibility across tested antimicrobial categories, 18/47 (38.3%) isolates were multidrug-resistant, including 15/29 (51.7%) hospital-derived and 3/18 (16.7%) community-derived isolates. Genomic analysis identified 17 {beta}-lactamase alleles including Morganella-associated chromosomal {beta}-lactamases and acquired resistance determinants, with blaOXA-1, blaDHA-21, blaCTX-M-15, and blaTEM-1 predominating. However, no recognized acquired carbapenemase genes were detected. Among 44 non-{beta}-lactam resistance genes, tetB was most frequent. Phylogenomic and average nucleotide identity analyses classified 31 isolates as M. morganii subsp. morganii and 16 as the subsp. intermedius lineage. Considerable population diversity was observed, with 33 distinct sequence types among the 47 isolates and no clear clustering by hospital or community origin. The subsp. intermedius isolates showed greater genomic heterogeneity than subsp. morganii, with a minimum within-group average nucleotide identity of 94.2%. Single nucleotide variant (SNV) analysis identified several closely related isolate groups, including an ST1 pair differing by 10 SNVs and collected three days apart within the same hospital, although direct transmission could not be established. Virulence-associated gene profiles differed between subspecies, with hemolysin- and toxin-associated genes predominantly detected among subsp. morganii isolates and largely absent from subsp. intermedius. Overall, these findings reveal substantial genomic diversity, a considerable burden of multidrug resistance, and subspecies-associated differences in virulence gene content among M. morganii circulating in Dhaka, while the frequent imipenem-non-susceptible but carbapenemase-negative phenotype highlights the need to investigate alternative carbapenem resistance mechanisms.

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Genetic Relationships of Third-Generation Cephem Resistant Escherichia coli in Humans, Dogs and Cattle using a Novel Clonotyping Assay

Legenza, L.; Jonaitis, E. M.; Lee, J. D.; Sokourenko, E. V.; Tchesnokova, V.; Hite, J. L.; Gao, S.; Olson, B. J.; Fritsche, T. R.

2026-09-25 infectious diseases 10.64898/2026.09.23.26363816 medRxiv
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Antimicrobial resistance is a global One Health threat connecting antimicrobial use in human health, animal husbandry, and companion animal health with concern for persistence in environmental reservoirs. Complicating this threat is the gap that exists in our understanding of the intersection of antimicrobial resistance among humans and our companion and food production animals. This study applies a visual and statistical approach to further understand antimicrobial resistance characteristics and relatedness of Escherichia coli found in humans, dogs and cattle. The primary study collection included third-generation cephem resistant (3GCR) E. coli isolates recovered from human, dog, and cattle gastrointestinal specimens and secondarily human and dog isolates recovered from infection sources, primarily urinary tract infections. We previously reported on the transferable gene targets encoding for 3GCR in colonizing isolates and here further identified the familial-like clonal group of each resistant isolate using a novel clonotype diagnostic (septatyping). Together, this approach identified distinct genetic signatures among these 3GCR isolates, many of which are peculiar to their respective host species. We found that the overlap measured by the correlation in abundance of shared clonotypes of resistant E. coli among hosts revealed statistically greater similarity between dogs and humans than between cattle and humans. Yet, the reservoir of AMR genes was highest in cattle and secondarily dogs. While these findings demonstrate that clonotypes of 3GCR E. coli in humans, dogs and cattle display significant host specificity, transient colonization from a host enriched with resistant strains may still pose considerable risk of horizontal transfer of resistance genes between hosts living in proximity to each other.

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Data Reduction in SARS-CoV-2 Amplicon Sequencing: Effects of Read Subsampling and Normalization on Consensus Quality, Lineage Assignment, and Computational Burden

Ortega, Y.; Gupta, P.; Olinares-Perdomo, O.; Oakeson, K. F.; Young, E. L.

2026-10-07 infectious diseases 10.64898/2026.10.05.26363801 medRxiv
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Background: Amplicon-based next-generation sequencing is a cornerstone of viral genomic surveillance, but it often produces datasets with highly uneven read coverage due to PCR amplification bias. This leads to excessive data generation and substantial computational overhead for downstream bioinformatic analysis. Results: We evaluated the efficacy of two data reduction strategies on 220 SARS-CoV-2 clinical specimens and 12 wastewater samples: random subsampling with SeqKit and read depth normalization with BBNorm. FASTQ files were reduced to target depths from 10X to 10,000X to compare genome coverage, lineage assignment concordance, and computational resource usage. Both strategies markedly reduced total processing time. For clinical isolates, read depth normalization corrected for amplification bias resulting in highly concordant lineage assignments at a target depth of just 200X. Random subsampling preserved inherent bias but produced reliable assignments at depths over 500X. Reducing target depths below 500X in complex wastewater mixtures severely degraded variant deconvolution accuracy and heavily skewed lineage abundance profiles for both methods. Conclusion: Both random subsampling and read depth normalization successfully reduce computational overhead while preserving key clinical sequencing metrics at appropriate reduction settings. The optimal method depends on the analytical goal, ranging from computationally lightweight random subsampling for rapid lineage assignment, to read depth normalization for generating high-quality consensus sequences. However, aggressive data reduction should be avoided in environmental surveillance, where maintaining a high baseline sequencing depth is critical for accurate mixed-variant deconvolution.

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Detecting measles virus in hospital air during a local outbreak

Barbian, H. J.; Funk, M.; Black, S. R.; Hayden, M. K.; Zelencik, S.; Borah, B. F.; Zhang, D.; Bartlett, A. H.; Kociolek, L. K.; Rosenthal, A.; Farhat, N.; McSorley, V. E.; Kittner, A.

2026-09-27 infectious diseases 10.64898/2026.09.25.26363929 medRxiv
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In 2024, Chicago experienced a measles virus outbreak. Air samples collected as part of routine respiratory virus surveillance from three hospitals that received measles patients were retrospectively analyzed. Measles virus was detected in air samples from one emergency department across five weeks when measles patients were present and another when no known cases were present. Two of three viral sequences derived from air samples were identical to measles patients. The source of one diverging sequence could not be identified and may represent a case not identified by traditional surveillance methods. Air sampling may supplement measles investigation, surveillance and response.

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Effectiveness of nirsevimab against hospitalization for RSV bronchiolitis according to RSV lineages

Barbier, M.; Levy, C.; Cohen, R.; Valtuille, Z.; Assad, Z.; Yang, J.-s.; Fafi, I.; Lenglart, L.; Bechet, S.; Osei, L.; Launay, E.; Gras Le Guen, C.; Gajdos, V.; Jeziorski, E.; De Pontual, L.; Basmaci, R.; Rameix-Welti, M.-A.; Ouldali, N.; Fourati, S.; French RSV Surveillance Network,

2026-09-29 pediatrics 10.64898/2026.09.28.26364231 medRxiv
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Importance: Nirsevimab, a monoclonal antibody against RSV, was implemented in France in September 2023. Recently, rare resistance-associated substitutions were described in RSV but the effectiveness according to lineages remains unclear. Objective: We aimed to estimate the effectiveness of nirsevimab against hospitalization for RSV bronchiolitis according to RSV lineages. Design: We conducted a multicenter test-negative case-control study from October 15, 2023 to March 15, 2025. Setting: This study was based on data from three national multicentric prospective studies. The 12 participating centers were secondary or tertiary hospital with a pediatric department located in France. Participants: We included all children younger than 12 months who were hospitalized for RSV bronchiolitis in one of the participating centers in France during the two first RSV epidemic seasons following the implementation of nirsevimab (from October 15, 2023 to February 29, 2024, and from October 10, 2024 to March 15, 2025). Main outcomes and measures: The main outcome of the study was the RSV test result of bronchiolitis cases. RSV whole-genome sequencing was performed using a tiled amplicon approach covering the complete viral genome, as previously described in the POLYRES studies. We estimated the effectiveness of nirsevimab by a multivariable logistic regression model adjusted for potential confounders. We estimated the adjusted risk of immunization failure for each lineage by calculating relative odds ratio to a reference lineage. A range of sensitivity analyses were conducted. Results: We included 3019 infants with bronchiolitis among which 2273 had a positive RSV test (case patients) and 746 had a negative RSV test (control patients). Overall, 373/2273 (16.4%) case patients were immunized by nirsevimab versus 423/746 (56.7%) control patients. The adjusted effectiveness of nirsevimab against hospitalization for bronchiolitis was 88.4% (95% CI, 84.5-91.4) with RSV-B and 79.4% (95% CI, 73.7-83.8) with RSV-A. The risk of immunization failure was 3.2-fold (95% CI 1.8-5.7) higher for lineages derived from A.D.3 than for lineages derived from B.D.4.1. Conclusion and relevance: In this multicentric case-control study, we observed that nirsevimab effectiveness was variable across RSV lineages, with a lower effectiveness against A.D.3 lineages compare to others. Further surveillance is needed to confirm these findings and assess their implication on RSV lineages epidemiology as nirsevimab use expands.

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Population pharmacokinetics of child-friendly dispersible amoxicillin/clavulanate tablets in African children with severe community acquired pneumonia

van Dyk, J.; Gebreyesus, M. S.; Clements, M.; Standing, J.; Moore, D.; Dangor, Z.; Waggie, Z.; Spittle, B.; Mulenga, V.; Chabala, C.; Mujuru, H.; Buck, W. C.; Sidat, M.; Sacarlal, J.; Bielicki, J. A.; Musiime, V.; Xu, H.; Madhi, S. A.; Sharland, M.; Denti, P.; Wasmann, R. E.; MRCCTU PediCAP,

2026-09-23 pediatrics 10.64898/2026.09.18.26362138 medRxiv
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BackgroundSevere community-acquired pneumonia (CAP) remains a leading cause of mortality in children under five. The PediCAP trial evaluated oral step-down therapy using dispersible amoxicillin or amoxicillin/clavulanate tablets in African children hospitalised with severe CAP. Dispersible tablet formulations are preferred in children; however, pharmacokinetic data for oral amoxicillin/clavulanate in paediatric populations remain limited. We characterised the pharmacokinetics of 4:1, 7:1, and 14:1 dispersible amoxicillin/clavulanate tablets in children enrolled in the PediCAP trial and predicted target attainment under different dosing schemes. MethodsChildren were randomised within 24 hours of starting intravenous antibiotics to oral step-down therapy with weight-banded dosing of twice-daily amoxicillin/clavulanate (4:1, 7:1, or 14:1). Plasma concentrations were quantified following intensive sampling and analysed using nonlinear mixed-effects modelling with allometric scaling and postmenstrual age-dependent clearance maturation. Pharmacodynamic indices included %fT>MIC for amoxicillin and %fT>Ct for clavulanate. ResultsA total of 157 children (median [range] age, 12 [2-70] months; weight, 8.4 [4.0-22.0] kg) contributed 707 paired concentrations. Amoxicillin was described by a two-compartment model and clavulanate by a one-compartment model, both with sequential zero-and first-order absorption. Typical clearance for an 8-kg individual at full maturation was 11.8L/h for amoxicillin and 6.1L/h for clavulanate. Pharmacokinetics were similar between the formulation ratios. Weight-banded dosing achieved balanced exposures across weight groups. Amoxicillin achieved 40%fT>MIC for MICs[&le;]2mg/L. A proposed clavulanate target of 20%fT>0.5mg/L was achieved in most children even at the lowest amoxicillin/clavulanate ratio. ConclusionWeight-banded dosing using dispersible amoxicillin/clavulanate tablets provide consistent exposure profiles in African children with severe CAP. SUMMARYPopulation pharmacokinetic modelling of dispersible amoxicillin/clavulanate tablets (4:1, 7:1, 14:1) in 157 African children with severe pneumonia showed weight-banded dosing achieved consistent and adequate amoxicillin and clavulanate exposures across formulations.

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National trends of unique-PCV20 / PCV21 serotypes, common PCV20-PCV21 and non-vaccine serotypes causing invasive pneumococcal disease in adults in Spain during the period 2009-2026

Garcia-Gonzalez, E.; Sempere, J.; Llamosi, M.; Perez-Garcia, C.; Ubeda, A.; Sanchez-Honrado, A.; Agullo, L.; Ardanuy, C.; Perez-Fernandez, L.; Ocampo-Sosa, A.; Ramos-Sevillano, E.; Brown, J. S.; Domenech, M.; Yuste, J.

2026-09-24 infectious diseases 10.64898/2026.09.22.26363691 medRxiv
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Objectives: To evaluate the epidemiological evolution of unique pneumococcal serotypes covered by either PCV20 or PCV21, common serotypes by both vaccines and non-vaccine serotypes in adults. Methods: We characterized all national IPD clinical isolates from January 2009 to June 2026. Results: The highest burden of IPD was caused by serotypes shared between PCV20 and PCV21 with serotypes 3 and 8 the most prevalent in adults of all ages. During the pre-pandemic period, IPD caused by unique-PCV20 serotypes declined probably due to herd protection by paediatric vaccination with PCVs. In contrast, unique-PCV21 serotypes increased in incidence accounting for more cases than unique-PCV20 serotypes. However, after the COVID-19 pandemic, a different pattern was observed with unique-PCV20 serotypes increasing in incidence due a marked rise in IPD caused by serotypes 4 and 14 that has progressively reduced the gap in disease coverage. In adults aged 18-64 years, the fraction of disease that could be prevented with PCV20/PCV21 changed from 5% in favour of PCV21 (years 2022/2023) to 15% in favour of PCV20 (year 2026) whereas in adults [&ge;]65 years the vaccine contribution declined from 20% in favour of PCV21 (year 2022) to 8% in 2026. Conclusions: IPD trends in adults have changed after the COVID-19 pandemic, especially in recent years. Our study emphasizes the rapid re-emergence of infections caused by traditional PCV7 serotypes especially serotypes 4 and 14 and reinforce the idea that the use of broader PCVs must be accompanied by an increase in the uptake rates in adults of all ages.

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Temporal Trends in Antimicrobial Resistance Among Clinically Important Pathogens in Iraq, 2021-2024: Implications for Empirical Antimicrobial Therapy

Darweesh, O.; Ahmed, H.; Al-Jawadi, H. K.; Kheder, R. K.; Alwiswasi, N. N.; Hameed, S. M.; Mohammed, H. F.; Kurdi, A. I. B.

2026-10-02 epidemiology 10.64898/2026.09.30.26364389 medRxiv
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To characterise temporal changes in antimicrobial resistance (AMR) among clinically important bacterial pathogens in Iraq during 2021-2024 and examine their implications for empirical antimicrobial therapy and stewardship. We conducted a retrospective longitudinal analysis of aggregated national AMR surveillance data for Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. Annual resistance proportions were evaluated across clinically relevant antimicrobials. Temporal change was characterised using absolute percentage-point changes and exploratory linear regression. Resistance trajectories were interpreted in relation to empirical treatment options and antimicrobial stewardship. The analysis included 92,338 organism records: 40,496 (43.9%) E. coli, 24,621 (26.7%) S. aureus, 18,223 (19.7%) K. pneumoniae and 8,998 (9.7%) P. aeruginosa. In 2024, ceftriaxone resistance reached 82.9% in E. coli and 65.2% in K. pneumoniae, while ciprofloxacin resistance was 55.4% and 57.9%, respectively. Meropenem resistance reached 37.4% in K. pneumoniae and 62.3% in P. aeruginosa. Conversely, resistance declined for amoxicillin-clavulanate in E. coli (83.5% in 2021 to 57.2% in 2024) and piperacillin-tazobactam in P. aeruginosa (46.4% to 32.9%). Several pathogen-antimicrobial combinations showed marked year-to-year variation, and no temporal trend remained statistically significant after false discovery rate correction. Resistance to several agents central to empirical therapy remains high in Iraq, while substantial carbapenem resistance constrains reliance on carbapenem escalation when resistance to other {beta}-lactams is suspected. Heterogeneous trajectories indicate that empirical recommendations should not rely on single-year national antibiograms alone and support regular integration of national and local resistance surveillance into empirical treatment and antimicrobial stewardship strategies.

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Nasopharyngeal aspirates and stool sample collection for molecular tuberculosis testing in children with severe pneumonia - a mixed methods study

Bhatta, B.; Bunnet, D.; Coleman, M.; Massom, D. M.; Djaha, J.; Banga, M.-F. L.; Kaing, S.; Voss de Lima, Y.; Mbalazi, K.; Komena, E.; Kwedi-Nolna, S.; Cumbe, S.; Natukunda, N.; Shankalala, P.; Nanfuka, M.; Roucher, C.; Lounnas, M.; Huyen Ton Nu Nguyet, M.; Vessiere, A.; Maillard, A.-L.; Ngu, E.; Joshi, B.; Borand, L.; Moh, R.; Khosa, C.; Chabala, C.; Mwanga-Amumpere, J.; Taguebue, J.-V.; Wobudeya, E.; Bonnet, M.; Marcy, O.; Orne-Gliemann, J.

2026-09-27 infectious diseases 10.64898/2026.09.24.26363964 medRxiv
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Background: Child-friendly sample collection methods are needed to improve microbiological tuberculosis diagnosis in children. We assessed the feasibility, diagnostic yield, safety, tolerability, and acceptability of nasopharyngeal aspirates (NPA) and stool sample collection for XpertMTB/RIF Ultra (Ultra) testing in children <5 years with severe pneumonia in six high tuberculosis incidence countries. Methods: We conducted a cross-sectional mixed-methods study (10/2020-03/2021) nested within the TB-Speed Pneumonia trial (NCT03831906) in 15 tertiary hospitals. Uptake and diagnostic yield of NPA and stool, sampled by trained nurses, were computed. Nurses documented NPA feasibility and related adverse events. NPA tolerability was assessed through discomfort/distress/pain scales completed by nurses, parents/caregivers, and children >3 years. Individual interviews investigated nurses and parents/caregivers perceptions and experiences of both procedures. Results: Of 542 children enrolled, 541 (99.8%) and 423 (75.5%) had NPA and stool samples successfully collected, respectively; 8 (1.5%) had positive Ultra on any sample, 8 (1.5%) on NPA, and 3 (0.6%) on stool samples. Nurses reported that NPA was difficult to collect in 27 (5.0%) children. 130 (24%) children had bloodstained NPA samples and <5% experienced transient heart rate deceleration, digestive or respiratory distress during NPA. Median nurse-assessed tolerability scores were 1/10 [0,3] before and 5/10 [2,6] during NPA. Although most respondents perceived NPA as painful, all appreciated that NPA aimed to improve child health. Nurses reported that NPA and stool collection was quicker, less invasive than gastric aspiration. Parents/caregivers trusted nurses skills and valued the novelty of NPA. All respondents easily engaged in stool collection, but were frustrated to depend on children passing stool. Nurses underlined that continuous staff training and mentoring would sustain feasibility and self-efficacy in obtaining adequate samples. Conclusions: NPA and stool are viable specimen collection options for microbiological diagnosis of tuberculosis in young children <5 years with severe pneumonia in high tuberculosis incidence countries.

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Safety, usability, patient comfort, and exploratory biofilm outcomes of the superhydrophilic antifouling LubriShield(R) Foley catheter: a randomised controlled trial

Romero, A. I.; Madhusudhan, S.; Krishnakumar, M.; Sambasivam, R.; Surkov, S.; Wirsen, P.; Bergström, L.; Brookes, G.; Leire, K.; Andersson, J.

2026-10-05 urology 10.64898/2026.09.29.26364294 medRxiv
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Background: Indwelling urinary catheters can cause pain, urethral irritation and trauma and provide surfaces for microbial colonisation and biofilm formation. The LubriShield(R) Foley catheter incorporates a covalently bonded, superhydrophilic antifouling hydrogel designed to reduce surface friction and limit biofilm accumulation without releasing an antimicrobial agent. This study evaluated its safety and clinical performance compared with an uncoated silicone Foley catheter, including usability and patient comfort, and explored catheter-associated microbial colonisation and biofilm formation. Methods: This prospective, randomised, single-blind, single-centre controlled clinical investigation enrolled 33 adults requiring indwelling urinary catheterisation for 72 hours to 14 days. Participants received either the LubriShield(R) Foley catheter (n = 16) or an uncoated Sterimed all-silicone Foley catheter (n = 17). The primary endpoint was safety based on adverse-event reporting; the prespecified safety criterion was the absence of a serious adverse device effect in the LubriShield(R) group. Secondary endpoints included investigator-rated ease and functionality of catheter insertion and removal and participant-reported pain and irritation/discomfort assessed using 0-10 numerical rating scales. Urine microbiology, catheter colonisation and catheter-level biofilm measurements were exploratory endpoints. Analyses were performed in the as-treated population. Numerical rating scale outcomes were compared using two-sided Mann-Whitney U tests; exploratory biofilm analyses used permutation tests with bootstrap confidence intervals. Results: No serious adverse events or serious adverse device effects occurred. Nine non-serious adverse events were reported and resolved completely. At least one adverse event occurred in 4/16 (25.0%) participants in the LubriShield(R) group and 4/17 (23.5%) participants in the control group. The prespecified safety criterion, defined as the absence of a SADE in the LubriShield(R) group, was met. LubriShield(R) was rated more favourably for ease of insertion (p = 0.0096), functionality during insertion (p = 0.0051), ease of removal (p = 0.0037) and functionality during removal (p = 0.0085). Participants reported significantly less pain and irritation/discomfort during insertion, while the catheter was indwelling and during removal (all p < 0.05). Outcomes 7 {+/-} 1 days after catheter removal were similar between groups. Absolute biofilm biomass and bacterial and fungal loads did not differ significantly. In a post hoc exploratory normalised analysis, the biofilm-to-bacterial-load ratio was lower with LubriShield(R) (median 0.052 vs 0.080; permutation p = 0.043), although the bootstrap 95% confidence interval for the between-group difference included zero. Conclusions: The LubriShield(R) Foley catheter demonstrated a favourable short-term safety profile and was associated with improved investigator-rated usability and participant-reported comfort compared with an uncoated silicone Foley catheter. A post hoc exploratory analysis was compatible with reduced biofilm accumulation relative to bacterial load, but this finding is hypothesis-generating only and requires confirmation in larger, adequately powered studies with prespecified biofilm endpoints.

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Cefazolin versus Antistaphylococcal Penicillins for Methicillin-Susceptible Staphylococcus aureus Bacteremia: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Pozzebon, F.; Pacheco, G.; Cabral, G.; Dias, B.; Macedo, R.; Assis, A.

2026-10-13 infectious diseases 10.64898/2026.10.12.26365331 medRxiv
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Purpose: To compare the efficacy and safety of intravenous cefazolin versus antistaphylococcal penicillins for the treatment of MSSA bacteremia in adults using evidence exclusively from randomized controlled trials. Methods: We searched 5 databases for RCTs comparing definitive intravenous cefazolin with ASPs (oxacillin, cloxacillin, flucloxacillin, nafcillin) in adults with MSSA bacteremia. Primary outcomes were 90-day all-cause mortality and acute kidney injury (AKI). Secondary outcomes included adverse event-related treatment discontinuation and persistent bacteremia (>72h). Dichotomous outcomes were synthesized as risk ratios (RRs) with 95% confidence intervals (CIs) using random-effects models with Paule-Mandel estimation and Hartung-Knapp-Sidik-Jonkman inference. Fixed-effect Mantel-Haenszel models were performed as sensitivity analyses. Results: Two RCTs randomized 1,656 participants (SNAP, n = 1,341; CloCeBa, n = 315), of whom 1,579 contributed to the 90-day mortality analysis. There was no statistically significant difference in 90-day mortality (RR 0.90, 95% CI 0.57-1.41; I2 = 0%). Both trials favoured cefazolin for acute kidney injury, but the random-effects estimate was highly imprecise (RR 0.26, 95% CI 0.00-939,970.59; I2 = 81.7%). Treatment discontinuation also favoured cefazolin directionally, although the random-effects estimate was imprecise (RR 0.24, 95% CI 0.00-24.41; I2 = 36.2%). Microbiological outcomes were synthesized narratively because definitions and assessment time points differed between trials. Conclusion: Randomized evidence supports cefazolin as a potential definitive treatment option when adequate source control, appropriate antimicrobial dosing, and clinical monitoring can be achieved. However, the limited number of trials and imprecision in pooled estimates warrant cautious interpretation.

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Wastewater metagenomic sequencing enables broad pathogen and resistome monitoring in Lagos, Nigeria

Parker, E.; Oladipo, F.; Levy, J. I.; Ope-Ewe, O. O.; Soumare, H.; Andersen, K.; Happi, A. N.; Happi, C. T.

2026-09-23 epidemiology 10.64898/2026.09.22.26363641 medRxiv
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Population-scale pathogen surveillance is limited worldwide, particularly in resource-constrained settings, where clinical systems only monitor select priority pathogens and reach only those who can access healthcare. Wastewater-based epidemiology addresses many of these gaps, offering cost-effective surveillance that is adaptable across diverse implementation contexts. In Lagos, Nigeria, a high enteric pathogen burden coincides with a complex sanitation landscape. However, circulating pathogen diversity in Lagos is largely uncharacterised outside of outbreak contexts. Here we characterize human-associated pathogen diversity in Lagos with virus-enriched metagenomic and metatranscriptomic sequencing of untreated wastewater sampled from open drainage canals from July-August 2024. We detected a diverse human-associated virome dominated by enteric adenoviruses, astroviruses and caliciviruses. We recovered numerous partial and near-complete genomes from pathogens of public health concern, including noroviruses, enteroviruses and sapoviruses. Although our enrichment targeted viruses, we detected diverse bacterial pathogens, including recurrent detection of Vibrio cholerae, other enteric bacteria, and zoonotic pathogens such as Streptococcus suis. We also detected antimicrobial resistance genes, including aminoglycoside, beta-lactam and fluoroquinolone resistance and clinically important genes such as mcr. Together, these results establish a regional baseline of pathogen diversity and demonstrate the utility of virus-enriched sequencing for integrated wastewater surveillance.