engleski

An outbreak of ESBL producing Salmonella Mikawasima in Split-Dalmatia County, Croatia 2020-2021

Background Non-typhoidal salmonellas usually cause mild gastroenteritis and don't require specific treatment. However, neonates and immunocompromised patients are at a high risk of developing severe disease.This study presents an outbreak of ESBL-producing Salmonella Mikawasima in Split- Dalmatia County (SDC), Croatia. Methods From April 2020 till October 2021, an unusual occurrence of S. Mikawasima in SDC was observed. A case was defined as a patient with diarrhea and an ESBLproducing S. Mikawasima in stool culture.The first case was observed in April 2020 at the Neonatal ward of the University Hospital Split (UH) followed by eleven cases during September and October 2020 at the same ward.Simultaneously, fifteen sporadic cases of the same salmonella serotype and resistotype were detected among outpatients at the Public Health Institute of Split-Dalmatia County (PHI) between May 2020 and August 2021.Cultivation was made by standard methods. Isolates were identified by MALDI TOF mass spectrometry, then serotyped. Antimicrobial susceptibility was tested by disk diffusion and Vitek 2 Compact methods. PFGE was performed according to the CDC protocol.The infection control teams at the UH and PHI were alerted to trace the source of infection. Stool samples from asymptomatic mothers and healthcare workers were obtained at the UHC, while positive outpatients were interviewed at the PHI. Croatian Food Agency was contacted to search possible food sources. Results In a total, 27 single S. Mikawasima isolates were obtained. All isolates had identical resistance (CTX-M like ESBL positive) and PFGE patterns.Surveillance stool cultures of neonates' mothers and healthcare workers were negative, except one. ESBL-producing S. Mikawasima grown from the stool specimen of an asymptomatic nurse. After her recovery, the outbreak at the Neonatal ward ended. There were no epidemiological links among positive outpatients except for two who had eaten the same package of smoked salmon. However, S. Mikawasima wasn't detected in a food chain in Croatia.

Salmonella Mikawasima, ESBL, outbreak

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