Use of the quantitative antibiogram method for assessing nosocomial transmission of ESBL-producing Enterobacterales in a French hospital.

BACKGROUND: Extended-spectrum beta-lactamase-producing Enterobacterales (eESBL) have high prevalence in hospitals, but real-time monitoring of nosocomial acquisition through conventional typing methods is challenging. Moreover, patient-to-patient transmission varies between the main species, namely Escherichia coli and Klebsiella pneumoniae, which draws into question the relevance of applying identical preventive measures. AIM: To detect eESBL cross-transmission events (CTEs) using the quantitative antibiogram (QA) method in combination with epidemiological data (combined QA method), and to determine the effectiveness of standard or contact precautions for eESBL species. METHODS: First, a validation set was used to compare the relevance of the combined QA method with a combination of pulsed-field gel electrophoresis and epidemiological data (combined PFGE method). Next, a 4-year retrospective analysis was conducted to detect eESBL CTEs in hospitalized patients. Two species were screened - ESBL E. coli (ESBL-Ec) and ESBL K. pneumoniae (ESBL-Kp). During the study, standard precautions alone were applied to patients with ESBL-Ec, whereas contact precautions were applied for patients with ESBL-Kp. FINDINGS: As a proof of concept, use of the combined QA method and the combined PFGE method for the detection of CTEs gave identical results for E. coli, and similar results for at least 75% of K. pneumoniae. Overall, 722 patients with ESBL-Ec isolates and 280 patients with ESBL-Kp isolates were included in the retrospective analysis. Nine and 23 CTEs were identified for E. coli and K. pneumoniae, respectively, involving 20 (2.7%) and 36 (12.8%) patients, respectively. CONCLUSION: The combined QA method constitutes a rapid tool for epidemiological surveillance to detect CTEs. In the study hospital, standard precautions are sufficient to prevent acquisition of ESBL-Ec, whereas contact precautions must be implemented to prevent acquisition of ESBL-Kp.

Clustered cases of infections due to an uncommon methicillin-resistant Staphylococcus aureus originating in a maternity ward.

OBJECTIVE: We aimed to report a community outbreak of an uncommon methicillin-resistant Staphylococcus aureus (MRSA) originating in a maternity ward. PATIENTS AND METHODS: Cases were defined by epidemiological, clinical, and microbiological investigations. Microbiological investigations included phenotypic analysis, molecular typing, and whole-genome sequencing. To control the outbreak, we applied both national recommendations to prevent in-hospital transmission and the French High Council for Public Health guidelines on the management of community-acquired MRSA infections. RESULTS: Between March and July 2016, seven patients with MRSA infections were identified: six skin and soft tissue infections and one pulmonary infection, including six microbiologically confirmed infections. Infections occurred in community settings, but a link with the same maternity ward was found for all patients. All MRSA strains had a t690 spa type, were tetracycline-resistant, and produced Panton-Valentine leukocidin. All isolates belonged to the sequence type 88 (ST88). CONCLUSION: This outbreak highlights the largely underestimated risk of healthcare-associated infections in maternity wards. Healthcare workers should be aware of the importance of standard hygiene precautions and use of alcohol-based hand sanitizers for neonates and mothers.