TY - JOUR
T1 - Laboratory-acquired infections of Salmonella enterica serotype Typhi in South Africa
T2 - Phenotypic and genotypic analysis of isolates
AU - GERMS-SA Surveillance Network
AU - Smith, Anthony Marius
AU - Smouse, Shannon Lucrecia
AU - Tau, Nomsa Pauline
AU - Bamford, Colleen
AU - Moodley, Vineshree Mischka
AU - Jacobs, Charlene
AU - McCarthy, Kerrigan Mary
AU - Lourens, Adré
AU - Keddy, Karen Helena
AU - Quan, Vanessa
AU - Nanoo, Ananta
AU - Gottberg, Anne von
AU - Dreyer, Andries
AU - Smith, Anthony Marius
AU - Sooka, Arvinda
AU - Miller, Cecilia
AU - Sriruttan, Charlotte
AU - Cohen, Cheryl
AU - Ihekweazu, Chikwe
AU - Mollendorf, Claire von
AU - Radebe, Frans
AU - Ntshoe, Genevie
AU - Hunt, Gillian
AU - Gouveia, Linda de
AU - Erasmus, Linda
AU - Smith, Marshagne
AU - Bodiba, Martha
AU - Khumalo, Mbhekiseni
AU - Modise, Motshabi
AU - Ismail, Nazir
AU - Govender, Nelesh
AU - Page, Nicola
AU - Perovic, Olga
AU - Murangandi, Oliver
AU - Crowther-Gibson, Penny
AU - Mutevedzi, Portia
AU - Manesen, Riyadh
AU - Mpembe, Ruth
AU - Iyaloo, Samantha
AU - Lengana, Sarona
AU - Madhi, Shabir
AU - Walaza, Sibongile
AU - Lindani, Sonwabo
AU - Meiring, Susan
AU - Motladiile, Thejane
AU - Chetty, Verushka
AU - Haumann, Carel
AU - Hanise, Patricia
AU - Vasaikar, Sandeep
AU - Nchabeleng, Maphoshane
N1 - Publisher Copyright:
© 2017 The Author(s).
PY - 2017/9/29
Y1 - 2017/9/29
N2 - Background: Workers in clinical microbiology laboratories are exposed to a variety of pathogenic microorganisms. Salmonella species is among the most commonly reported bacterial causes of laboratory-acquired infections. We report on three cases of laboratory-acquired Salmonella enterica serotype Typhi (Salmonella Typhi) infection which occurred over the period 2012 to 2016 in South Africa. Methods: Laboratory investigation included phenotypic and genotypic characterization of isolates. Phenotypic analysis included standard microbiological identification techniques, serotyping and antimicrobial susceptibility testing. Genotypic analysis included the molecular subtyping methodologies of pulsed-field gel electrophoresis analysis, multilocus sequence typing and whole-genome sequencing (WGS); with WGS data analysis including phylogenetic analysis based upon comparison of single nucleotide polymorphism profiles of isolates. Results: All cases of laboratory-acquired infection were most likely the result of lapses in good laboratory practice and laboratory safety. The following critical issues were highlighted. There was misdiagnosis and misreporting of Salmonella Typhi as nontyphoidal Salmonella by a diagnostic laboratory, with associated public health implications. We highlight issues concerning the importance of accurate fluoroquinolone susceptibility testing and interpretation of results according to updated guidelines. We describe potential shortcomings of a single disk susceptibility screening test for fluoroquinolone susceptibility and suggest that confirmatory minimum inhibitory concentration testing should always be performed in cases of invasive Salmonella infections. These antimicrobial susceptibility testing issues resulted in inappropriate ciprofloxacin therapy which may have been responsible for failure in clearance of pathogen from patients. Salmonella Typhi capsular polysaccharide vaccine was not protective in one case, possibly secondarily to a faulty vaccine. Conclusions: Molecular subtyping of isolates proved effective to investigate the genetic relatedness of isolates. Molecular subtyping data interpreted together with epidemiological data allowed us to pinpoint the most likely sources for our cases of laboratory-acquired infection.
AB - Background: Workers in clinical microbiology laboratories are exposed to a variety of pathogenic microorganisms. Salmonella species is among the most commonly reported bacterial causes of laboratory-acquired infections. We report on three cases of laboratory-acquired Salmonella enterica serotype Typhi (Salmonella Typhi) infection which occurred over the period 2012 to 2016 in South Africa. Methods: Laboratory investigation included phenotypic and genotypic characterization of isolates. Phenotypic analysis included standard microbiological identification techniques, serotyping and antimicrobial susceptibility testing. Genotypic analysis included the molecular subtyping methodologies of pulsed-field gel electrophoresis analysis, multilocus sequence typing and whole-genome sequencing (WGS); with WGS data analysis including phylogenetic analysis based upon comparison of single nucleotide polymorphism profiles of isolates. Results: All cases of laboratory-acquired infection were most likely the result of lapses in good laboratory practice and laboratory safety. The following critical issues were highlighted. There was misdiagnosis and misreporting of Salmonella Typhi as nontyphoidal Salmonella by a diagnostic laboratory, with associated public health implications. We highlight issues concerning the importance of accurate fluoroquinolone susceptibility testing and interpretation of results according to updated guidelines. We describe potential shortcomings of a single disk susceptibility screening test for fluoroquinolone susceptibility and suggest that confirmatory minimum inhibitory concentration testing should always be performed in cases of invasive Salmonella infections. These antimicrobial susceptibility testing issues resulted in inappropriate ciprofloxacin therapy which may have been responsible for failure in clearance of pathogen from patients. Salmonella Typhi capsular polysaccharide vaccine was not protective in one case, possibly secondarily to a faulty vaccine. Conclusions: Molecular subtyping of isolates proved effective to investigate the genetic relatedness of isolates. Molecular subtyping data interpreted together with epidemiological data allowed us to pinpoint the most likely sources for our cases of laboratory-acquired infection.
KW - Genotyping
KW - Laboratory-acquired infection
KW - MLST
KW - Molecular subtyping
KW - PFGE
KW - Salmonella Typhi
KW - South Africa
KW - WGS
KW - Whole-genome sequencing
UR - http://www.scopus.com/inward/record.url?scp=85030237488&partnerID=8YFLogxK
U2 - 10.1186/s12879-017-2757-2
DO - 10.1186/s12879-017-2757-2
M3 - Article
C2 - 28962627
AN - SCOPUS:85030237488
SN - 1471-2334
VL - 17
JO - BMC Infectious Diseases
JF - BMC Infectious Diseases
IS - 1
M1 - 656
ER -