Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia

Introduction: Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin resistant (Optr) S. pneumoniae identification is essential....

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Main Authors: Sonia Ktari, Nour El Houda Ben Ayed, Sonda Maalej, Basma Mnif, Faouzia Rhimi, Adnene Hammami
Format: Article
Language:English
Published: The Journal of Infection in Developing Countries 2021-05-01
Series:Journal of Infection in Developing Countries
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Online Access:https://jidc.org/index.php/journal/article/view/13106
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author Sonia Ktari
Nour El Houda Ben Ayed
Sonda Maalej
Basma Mnif
Faouzia Rhimi
Adnene Hammami
author_facet Sonia Ktari
Nour El Houda Ben Ayed
Sonda Maalej
Basma Mnif
Faouzia Rhimi
Adnene Hammami
author_sort Sonia Ktari
collection DOAJ
description Introduction: Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin resistant (Optr) S. pneumoniae identification is essential. Methodology: Atypical pneumococci were characterized using optochin susceptibility, bile solubility based on spectrophotometric reading, serotyping, pulsed field gel electrophoresis (PFGE), 16S rRNA sequencing and PCR-based assays targeting pneumococcal genes lytA, ply, pspA, cpsA, Spn9802 and Spn9828. Results: Optical density values for the bile solubility test suggest the identification of four Optr S. pneumoniae and one Streptococcus pseudopneumoniae. All Optr pneumococci harbored cpsA, lytA, ply, Spn9802, Spn9828 and pspA genes. Only ply, spn9802 and Spn9828 genes were detected in S. pseudopneumoniae. The 16S rRNA sequencing differentiates between these two species. Optr S. pneumoniae strains belonged to different genotypes and serotypes (14, 19A, 3 and 9V). Three Optr S. pneumoniae isolates were typed as pspA family 2, while one belonged to pspA family 1. Sequencing of the atpA and atpC gene of the Optr variants revealed three mutations in the ATPase a-subunit (L99I, M23V and V52I) and one mutation in ATPase c-subunit (V48I). Conclusions: Our data indicate that bile OD-values provides an accurate, fast and easy method to discriminate between Optr S. pneumoniae and other Streptococcus mitis group. Moreover molecular techniques, confirming the bile test, can be used in order to prevent these atypical pneumococci and alert clinical microbiologists of the presence of these strains in the community.
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spelling doaj-art-b5f91d7885934644a8406ad7ef7264212025-08-20T02:57:21ZengThe Journal of Infection in Developing CountriesJournal of Infection in Developing Countries1972-26802021-05-01150510.3855/jidc.13106Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in TunisiaSonia Ktari0Nour El Houda Ben Ayed1Sonda Maalej2Basma Mnif3Faouzia Rhimi4Adnene Hammami5Laboratory of Microbiology, Medical School of Sfax, TunisiaHabib Bourguiba University Hospital, Sfax, TunisiaHabib Bourguiba University Hospital, Sfax, TunisiaHabib Bourguiba University Hospital, Sfax, TunisiaHabib Bourguiba University Hospital, Sfax, TunisiaHabib Bourguiba University Hospital, Sfax, Tunisia Introduction: Streptococcus pneumoniae can be responsible for severe human infections. Optochin resistance has been a potential cause of misidentification of pneumococcus and other members of the mitis group. Hence, rapid and easy optochin resistant (Optr) S. pneumoniae identification is essential. Methodology: Atypical pneumococci were characterized using optochin susceptibility, bile solubility based on spectrophotometric reading, serotyping, pulsed field gel electrophoresis (PFGE), 16S rRNA sequencing and PCR-based assays targeting pneumococcal genes lytA, ply, pspA, cpsA, Spn9802 and Spn9828. Results: Optical density values for the bile solubility test suggest the identification of four Optr S. pneumoniae and one Streptococcus pseudopneumoniae. All Optr pneumococci harbored cpsA, lytA, ply, Spn9802, Spn9828 and pspA genes. Only ply, spn9802 and Spn9828 genes were detected in S. pseudopneumoniae. The 16S rRNA sequencing differentiates between these two species. Optr S. pneumoniae strains belonged to different genotypes and serotypes (14, 19A, 3 and 9V). Three Optr S. pneumoniae isolates were typed as pspA family 2, while one belonged to pspA family 1. Sequencing of the atpA and atpC gene of the Optr variants revealed three mutations in the ATPase a-subunit (L99I, M23V and V52I) and one mutation in ATPase c-subunit (V48I). Conclusions: Our data indicate that bile OD-values provides an accurate, fast and easy method to discriminate between Optr S. pneumoniae and other Streptococcus mitis group. Moreover molecular techniques, confirming the bile test, can be used in order to prevent these atypical pneumococci and alert clinical microbiologists of the presence of these strains in the community. https://jidc.org/index.php/journal/article/view/13106S. pneumoniaeS. pseudopneumoniaeoptochin resistancebile solubilitymolecular techniques
spellingShingle Sonia Ktari
Nour El Houda Ben Ayed
Sonda Maalej
Basma Mnif
Faouzia Rhimi
Adnene Hammami
Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia
Journal of Infection in Developing Countries
S. pneumoniae
S. pseudopneumoniae
optochin resistance
bile solubility
molecular techniques
title Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia
title_full Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia
title_fullStr Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia
title_full_unstemmed Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia
title_short Clinical optochin resistant Streptococcus pneumoniae and Streptococcus pseudopneumoniae strains in Tunisia
title_sort clinical optochin resistant streptococcus pneumoniae and streptococcus pseudopneumoniae strains in tunisia
topic S. pneumoniae
S. pseudopneumoniae
optochin resistance
bile solubility
molecular techniques
url https://jidc.org/index.php/journal/article/view/13106
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