Galan-Sanchez, F. | bioRxiv Science

bioRxiv2024

Performance of the BD Phoenix CPO detect assay for the detection and classification of OXA-48 producing-Escherichia coli that do not coproduce ESBL/pAmpC

Reliable detection of OXA-48-like enzymes in routine antimicrobial susceptibility testing is difficult, especially if the isolate does not coproduce other beta-lactamases. The BD Phoenix Emerge panel includes the CPO Detect Test (CPO-T), which allows simultaneous antimicrobial susceptibility testing and carbapenemase detection and characterization. We evaluated the accuracy of detection and classification of carbapenemases determined by CPO-T against a characterized set of OXA-48-producing Escherichia coli isolates that do not co-produce ESBL/pAmpC, and BD Phoenix for rapid antimicrobial susceptibility testing. A total of 51 E. coli isolates were included All the isolates were sequenced using Illumina and analyzed using Resfinder and CARD for resistance determinants, MLSTfinder for typing and Clermont Phylotyper for phylotypes. CPO-T was performed within the BD Phoenix NMIC-502 panel. Disk diffusion, with readings at 4, 6, 8 and 24 hours, was performed as reference method (RDD). The CPO-T detected carbapenemase activity in 100% of the isolates within 7 hours of incubation and 42 (82.4%) isolates were correctly assigned to the class D Ambler. For all isolates and antibiotics, BD Phoenix provided definitive susceptibility results in less than 8 hours in 64.6% of cases compared to 58.2% with RDD. Overall categorical agreement was 90.7% and 5.9% very major, 6.2% major and 3.2% minor errors were observed. Our results demonstrate that CPO-T is a reliable tool for the detection of OXA-48 in E. coli isolates that do not co-produce ESBL/pAmpC without the need for additional testing, and that BD Phoenix provides rapid results for the antibiotics most commonly used in empirical treatment. IMPORTANCEDetection of OXA-48-like enzymes in isolates that do not co-produce other beta-lactamases in routine antimicrobial susceptibility testing is difficult, and studies on these types of isolates are scarce. Our study analyzes the performance of the BD Phoenix Emerge panel, which includes the CPO detection test (CPO-T), in a characterized set of OXA-48-producing Escherichia coli isolates that do not co-produce ESBL/pAmpC, and also provide information about time to results of this system.

microbiology↗

bioRxiv2024

Genotypic Characterization and Antimicrobial Susceptibility of Human Campylobacter jejuni Isolates in Southern Spain

Campylobacter jejuni is the main cause of bacterial gastroenteritis and a public health problem worldwide. Little information is available on the genotypic characteristics of human Campylobacter jejuni in Spain. This study is based on an analysis of the resistome, virulome and phylogenetic relationship, antibiogram prediction and antimicrobial susceptibility of 114 human isolates of C. jejuni from a tertiary hospital in southern Spain from October 2020 to June 2023. The isolates were sequenced using Illumina technology, and bioinformatic analysis was subsequently performed. The susceptibility of C. jejuni isolates to ciprofloxacin, tetracycline, and erythromycin was tested. A high resistance rate was obtained for ciprofloxacin (90.6%) and tetracycline (66.7%), and a low resistance rate for erythromycin (0.85%) was detected among the C. jejuni isolates. CC-21 (n=23), ST-572 (n = 13) and ST-6532 (n=13) were the most prevalent clonal complexes (CCs) and sequence types (STs). Concerning the virulome, the cadF, ciaB, and cdtABC genes were detected in all the isolates. A prevalence of 20.1% was obtained for the genes wlaN and cstIII, which are related to the pathogenesis of Guillain-Barre syndrome (GBS). The prevalence of the main antimicrobial resistance markers detected were cmeABC (92.1%), RE-cmeABC (7.9%), the T86I substitution in gyrA (88.9%), blaOXA-61 (72.6%), tet(O) (65.8%) and ant(6)-Ia (17.1%). High antibiogram prediction rates (>97%) were obtained except for the erythromycin-resistant phenotype. This study contributes significantly to the knowledge of Campylobacter jejuni genomics for the prevention, treatment and control of infections caused by this pathogen, which is relevant to public health. ImportanceDespite being the pathogen with the greatest number of gastroenteritis cases worldwide, Campylobacter jejuni remains a poorly studied microorganism. The development of whole-genome sequencing (WGS) techniques has led to a better understanding of the genotypic characteristics of this pathogen. These techniques complement the data obtained from the phenotypic analysis of C. jejuni isolates. The zoonotic transmission of C. jejuni through the consumption of contaminated poultry implies approaching the study of this pathogen through the term "One Health." This is the first study, using WGS, conducted on human isolates of C. jejuni in Spain to date, which allows comparison of the results obtained with similar studies conducted in other countries and with animal and environmental isolates.

microbiology↗