Genomic insights of Leclercia adecarboxylata strains linked to an outbreak in public hospitals in Mexico.

BACKGROUND: Leclercia adecarboxylata is a bacteria closely related to Escherichia coli according to its biochemical characteristics and is commonly considered non-pathogenic although a growing number of publications classify it as an emerging pathogen. Fosfomycin resistance is a common trait for L. adecarboxylata encoded by fosALA gene. OBJECTIVE: To analyze genomic traits of sixteen L. adecarboxylata strains isolated from blood culture and a bottle of total parenteral nutrition. METHODS: Twenty-eight L. adecarboxylata strains isolated from blood culture and a bottle of total parenteral nutrition were identified biochemically with a Vitek ® automated system. The strains were phenotyped by their growth on Eosin Methylene Blue agar or MacConkey agar plates. Additionally, Pulsed field gel electrophoresis (PFGE) was performed to establish the clonal relationship. The genomic DNA of sixteen strains was obtained using a Qubit ® dsDNA HS Assay Kit and sequenced on an Illumina ® MiSeq instrument. Draft genomes were assembled using PROKKA and Rast. Assemblies were submitted to Resfinder and PathogenFinder from the Center for Genomic Epidemiology in order to find resistance genes and pathogenic potential. IslandViewer4 was also used to find Pathogenicity and Phage Islands. For identification of the fosA gene, manual curation and Clustal analysis was performed. A novel FosA variant was identified. Finally, phylogenetic analysis was performed using VAMPhyRE software and Mega X. RESULTS: In this paper, we report the genomes of sixteen strains of Leclercia adecarboxylata causing an outbreak associated with parenteral nutrition in public hospitals in Mexico. The genomes were analyzed for genetic determinants of virulence and resistance. A high pathogenic potential (pathogenicity index 0.82) as well as multiple resistance genes including carbapenemics, colistin and efflux pumps were determined. Based on sequence analysis, a new variant of the fosALA gene was described. Finally, the outbreak was confirmed by establishing the clonal relationship among the sixteen genomes obtained. CONCLUSIONS: Commensal strains of L. adecarboxylata may acquire genetic determinants that provide mechanisms of host damage and go unnoticed in clinical diagnosis. L. adecarboxylata can evolve in a variety of ways including the acquisition of resistance and virulence genes representing a therapeutic challenge in patient care.

Antimicrobial resistance and antibiotic consumption in a third level pediatric hospital in Mexico City.

INTRODUCTION: The increasing resistance to antibiotics is a public health problem and an imminent therapeutic challenge in hospitals. In this report we aimed to analyze the relationship between antimicrobial resistance and antibiotic consumption in a third-level pediatric hospital. METHODOLOGY: A cross-sectional analysis was conducted using the information from the microbiology and pharmacy databases of the Pediatric Hospital "Doctor Silvestre Frenk Freund", during the period 2015-2018. Prevalence of antimicrobial resistance by microorganisms and dispensed grams of selected antibiotics were calculated annually. Antibiotic resistance trend over the time was evaluated using the Chi-square trends test and to assess the correlation between the dispensed grams of antibiotics with their antimicrobial resistance prevalence, we calculated the Pearson's coefficient (r). RESULTS: A total of 4,327 isolated bacterial samples were analyzed (56.5% Gram-positive and 44.5% Gram-negative). Most frequently isolated microorganisms were coagulase-negative staphylococci (CoNS), E. coli, K. pneumoniae, P. aeruginosa and S. aureus. We found a significant increase in resistance to clindamycin and oxacillin for CoNS and significant decrease in nitrofurantoin and amikacin resistance for E. coli and K. pneumoniae. We observed a strong positive and statistically significant correlation between amikacin resistance prevalence and amikacin dispensed grams for P. aeruginosa (r = 0.95, p = 0.05). CONCLUSIONS: The antibiotic resistance profile showed by our study highlights the need of an appropriate antibiotic control use in the Hospital setting.