Local outbreak of extended-spectrum ß-lactamase SHV2a-producing Pseudomonas aeruginosa reveals the emergence of a new specific sub-lineage of the international ST235 high-risk clone.

BACKGROUND: Pseudomonas aeruginosa is a major bacterial pathogen responsible for hospital-acquired infections. Although its epidemiology is considered as non-clonal, certain international high-risk multidrug-resistant clones have been recognized. AIM: From the first report of an intra-hospital outbreak due to an SHV2a-producing P. aeruginosa strain, to describe the emergence of a new ST235-specific lineage harbouring this rare extended-spectrum ß-lactamase (ESBL). METHODS: Between May and October 2018, four patients hospitalized in the cardiovascular intensive care unit of a French teaching hospital were infected by a multidrug-resistant P. aeruginosa isolate. Serotype and antimicrobial susceptibility were tested; multi-locus sequence type (MLST), core genome MLST, and resistome were determined through whole genome sequencing. A phylogenetic analysis based on single nucleotide polymorphism was performed using available ST235 genomes. FINDINGS: The four strains were susceptible to colistin, ciprofloxacin, ceftazidime-avibactam, and ceftolozane-tazobactam. blaSHV2a was identified in each genome of this ST235-O11 serotype cluster that showed an identical cgMLST profile (0-2 out of 4162 different alleles). The phylogenic analysis of 162 ST235 genomes showed that only four other strains harboured a blaSHV2a, originating from France and USA, clustering together although being different from the outbreak strains. CONCLUSIONS: Among the ST235 P. aeruginosa strains, a sub-lineage sharing a common genetic background and harbouring the blaSHV2a ESBL seems to emerge from different locations, yielding secondary local outbreaks.

Vascular graft infection due to Pasteurella multocida.

BACKGROUND: Vascular graft infections are infrequent complications with important morbidity and mortality rates. Pasteurella multocida, a Gram negative bacillus, is a normal oral commensal of many animals. For mankind, it is a pathogenous bacillus which is rarely implicated in vascular grafts. CASE REPORT: We report hereafter the fourth case introduced in the international literature about vascular graft infections caused by P. multocida. The patient was successfully treated with a combination of a surgical graft change and a 6 weeks bi-antibiotic therapy. DISCUSSION: There is fours case reported in litterature with quite different antibiotic drugs and duration. CONCLUSION: P. multicoda graft infection should be long with initial intravenous drug and mainteance traitement should not be required.