Abstract Background Surveillance data for Pseudomonas aeruginosa in the USA are distributed across systems designed for different purposes, potentially limiting standardized national surveillance of high-priority resistant phenotypes. We evaluated whether the Centers for Disease Control and Prevention (CDC) National Notifiable Diseases Surveillance System (NNDSS) can support surveillance of multidrug-resistant (MDR) P. aeruginosa and synthesized available CDC surveillance data to characterize the residual surveillance gap. Methods We reviewed the 2026 NNDSS list of nationally notifiable conditions for P. aeruginosa. Because neither P. aeruginosa infection nor a resistant phenotype was present, NNDSS case counts were unable to be analysed. We therefore conducted a descriptive secondary analysis of CDC National Healthcare Safety Network (NHSN) reports for 2018–21 and the 2022 NHSN Antimicrobial Resistance (AR) Option report. Results In 2018–21 adult NHSN data, 11.9% of tested P. aeruginosa isolates from device-associated infections were MDR, compared with 3.9% from surgical-site infections. Among central-line-associated bloodstream infection isolates, MDR proportions were highest in long-term acute-care hospitals (LTACHs, 25.3%), followed by hospital intensive-care units (14.2%), hospital wards (11.9%) and oncology units (8.5%). Among catheter-associated urinary tract infection isolates, MDR phenotype was observed in 20.8% of LTACH isolates. In the 2022 AR Option report, carbapenem non-susceptibility exceeded 10% among community-onset isolates and approached 20% among hospital-onset isolates. Conclusions NNDSS cannot currently quantify the burden of MDR P. aeruginosa, but substantial resistance surveillance is available through NHSN and the CDC AR Laboratory Network. The principal gap is not an absence of surveillance data but fragmentation across systems with different populations, denominators, objectives and reporting mechanisms.
BACKGROUND Africa remains a major epicentre of the global HIV epidemic, with Central Africa exhibiting extensive HIV-1 genetic diversity that may influence the emergence and transmission of drug resistance mutations. Following World Health Organization recommendations, Angola initiated the national transition to dolutegravir (DTG)-based antiretroviral therapy (ART) in 2021. This study evaluated the frequency, patterns and temporal trends of HIV-1 drug resistance mutations before and after DTG implementation (2019-23), while also characterizing HIV-1 genetic diversity across Angolan provinces outside Luanda. METHODS A retrospective observational analytical study comparing pre- and post-Integrase strand transfer inhibitor (INSTI) introduction periods was conducted using plasma samples and dried blood spot cards from 17 provinces of Angola. RESULTS Of the 201 samples analysed, 102 were successfully sequenced for at least one coding region [protease (n = 65); reverse transcriptase (n = 66); integrase (IN) (n = 86)], comprising 48 INSTI-naive people living with HIV and 54 INSTI-experienced people living with HIV samples. Subtype C was the most prevalent (21.6%), followed by unique recombinant forms (20.6%), A1 (15.7%), F1 (13.7%), CRF02_AG (10.8%), G (8.8%) and other subtypes or recombinants (8.8%). Resistance to non-nucleoside reverse transcriptase inhibitors was the most common (68.2%; 95% CI 56.2-78.2), followed by nucleoside reverse transcriptase inhibitors (48.5%; 95% CI 36.8-60.3). Resistance to protease inhibitors (PIs) and INSTIs was lower, observed in 1.5% (95% CI 0.3-8.2) and 3.5% (95% CI 1.2-9.8), respectively. CONCLUSIONS In this analysis, substantial HIV-1 genetic and epidemiological complexity was observed. In the context of the rapid scale-up of DTG-based ART, continued surveillance of INSTI resistance mutations has become increasingly important to inform evidence-based public health strategies aimed at preventing the transmission of drug-resistant HIV strains and optimizing ART regimens at the population level.
Abstract Objectives The two reference broth microdilution antifungal susceptibility methods, developed by the CLSI and EUCAST, were compared qualitatively and quantitatively using an international collection of 107 Candida (Candidozyma) auris clinical isolates including azole- and echinocandin-resistant isolates. Methods Inter-method agreement within ±1 twofold dilution was assessed for all drugs. Categorical agreement (CA) was evaluated for amphotericin B, anidulafungin and micafungin using the CDC tentative resistance breakpoints and the recently proposed EUCAST clinical breakpoints for C. auris. Results CLSI-EUCAST agreement was moderate to strong for itraconazole (44%), posaconazole (52%), isavuconazole (70%), voriconazole (72%), micafungin (81%), caspofungin (86%), and anidulafungin (87%), and excellent for 5-flucytosine (93%) and amphotericin B (100%). All isolates were categorized as non-resistant to amphotericin B by both methods (100% CA). CA was 92% for anidulafungin and 94% for micafungin, with 8% and 6% major errors, respectively, with CDC breakpoints classifying 33%–44% of FKS1 mutants as non-resistant. While all FKS1 mutants exceeded EUCAST ECOFF values, 11% and 28% fell at or below the corresponding CLSI ECV values for micafungin (0.5 mg/L) and anidulafungin (1 mg/L), respectively, with MICs 0.5–1 mg/L. For caspofungin, all non-wild-type isolates harboured FKS1 mutations, but 6% of isolates without FKS1 mutations had MICs 1 dilution higher than CLSI ECV for caspofungin (0.5 mg/L). Conclusions Despite high overall concordance between CLSI and EUCAST MICs, discrepancies in wild-type classification among FKS1 mutants highlight the need for harmonized interpretive criteria. Azole MIC variability further underscores the need for standardized breakpoints.
Abstract Objectives Necrotizing soft tissue infections (NSTIs) are rapidly progressive, life-threatening infections requiring prompt surgical and antimicrobial treatment. We aimed to characterize the microbiological profiles and antimicrobial resistance patterns of NSTIs and to assess their associations with 90-day mortality. Methods We retrospectively studied 212 adults with NSTIs admitted from December 2008 to May 2025. Clinical characteristics, laboratory parameters, pathogen groups and antimicrobial susceptibility patterns were compared between survivors and non-survivors. All 40 candidate factors were jointly included in ridge-penalized logistic regression, and estimation stability was assessed using bootstrap resampling. Results Overall 90-day mortality was 29.7% (63/212), and Gram-negative infections predominated (43.9%, 93/212). Mortality was 40.0% (12/30), 33.3% (31/93), and 66.7% (2/3) in Gram-positive, Gram-negative and fungal infections, respectively. Resistance analysis included 127 bacterial isolates from nine predominant taxa. Penicillin G resistance in Staphylococcus aureus and oxacillin resistance in coagulase-negative staphylococci were both 80.0%. Streptococcus pyogenes showed resistance to erythromycin and clindamycin in 75.0% and 62.5% of isolates, respectively. Among Escherichia coli isolates, ESBL positivity and resistance to levofloxacin and ciprofloxacin each occurred in 66.7%. Cefepime resistance was detected in 5.88% of Vibrio vulnificus isolates. In the jointly fitted ridge model, cardiovascular disease, hypertension, shock within 24h, coagulation measures, bilirubin, creatine kinase, potassium and lactate showed positive associations with mortality, whereas white blood cell count, albumin, CRP and PaCO2 showed inverse associations. Conclusions This long-term NSTI cohort showed Gram-negative predominance and species-specific heterogeneity in antimicrobial resistance. The ridge-penalized multivariable analysis characterized associations of microbiological categories and clinical indicators with 90-day mortality. These findings support locally tailored empirical therapy and the assessment of mortality risk.
