Dataset Information

Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element.

ABSTRACT: Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus sequence typing (MLST), capsular polysaccharide typing and in vitro antimicrobial susceptibility testing. We analysed the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS from East Africa in order to investigate the level of genetic exchange between GBS populations in the region. Camel GBS sequence types (STs) were distinct from other STs reported so far. We mapped specific STs and capsular types to major disease complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with acquisition of the tetM gene that is carried on a Tn916-like element, and observed primarily among GBS isolated from mastitis. The presence of tetM within different MLST clades suggests acquisition on multiple occasions. Wound infections and mastitis in camels associated with GBS are widespread and should ideally be treated with antimicrobials other than tetracycline in East Africa.

SUBMITTER: Fischer A

PROVIDER: S-EPMC3850529 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element.

Fischer Anne A Liljander Anne A Kaspar Heike H Muriuki Cecilia C Fuxelius Hans-Henrik HH Bongcam-Rudloff Erik E de Villiers Etienne P EP Huber Charlotte A CA Frey Joachim J Daubenberger Claudia C Bishop Richard R Younan Mario M Jores Joerg J

Veterinary research 20131001

Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role in the nutritional sustainability for millions of people. Their health status is therefore of utmost importance for the people living in this region. Streptococcus agalactiae, a Group B Streptococcus (GBS), is an important camel pathogen. Here we present the first epidemiological study based on genetic and phenotypic data from African camel derived GBS. Ninety-two GBS were characterized using multilocus ...[more]

PMID: 24083845

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Project description:Three vancomycin-resistant streptococcal strains carrying vanG elements (two invasive Streptococcus agalactiae isolates [GBS-NY and GBS-NM, both serotype II and multilocus sequence type 22] and one Streptococcus anginosus [Sa]) were examined. The 45,585-bp elements found within Sa and GBS-NY were nearly identical (together designated vanG-1) and shared near-identity over an ~15-kb overlap with a previously described vanG element from Enterococcus faecalis. Unexpectedly, vanG-1 shared much less homology with the 49,321-bp vanG-2 element from GBS-NM, with widely different levels (50% to 99%) of sequence identity shared among 44 related open reading frames. Immediately adjacent to both vanG-1 and vanG-2 were 44,670-bp and 44,680-bp integrative conjugative element (ICE)-like sequences, designated ICE-r, that were nearly identical in the two group B streptococcal (GBS) strains. The dual vanG and ICE-r elements from both GBS strains were inserted at the same position, between bases 1328 and 1329, within the identical RNA methyltransferase (rumA) genes. A GenBank search revealed that although most GBS strains contained insertions within this specific site, only sequence type 22 (ST22) GBS strains contained highly related ICE-r derivatives. The vanG-1 element in Sa was also inserted within this position corresponding to its rumA homolog adjacent to an ICE-r derivative. vanG-1 insertions were previously reported within the same relative position in the E. faecalis rumA homolog. An ICE-r sequence perfectly conserved with respect to its counterpart in GBS-NY was apparent within the same site of the rumA homolog of a Streptococcus dysgalactiae subsp. equisimilis strain. Additionally, homologous vanG-like elements within the conserved rumA target site were evident in Roseburia intestinalis. Importance: These three streptococcal strains represent the first known vancomycin-resistant strains of their species. The collective observations made from these strains reveal a specific hot spot for insertional elements that is conserved between streptococci and different Gram-positive species. The two GBS strains potentially represent a GBS lineage that is predisposed to insertion of vanG elements.

Project description:BackgroundThe clinical significance of group B streptococcus (GBS) was different among different clonal complexes (CCs), accurate strain typing of GBS would facilitate clinical prognostic evaluation, epidemiological investigation and infection control. The aim of this study was to construct a practical and facile CCs prediction model for S. agalactiae.MethodsA total of 325 non-duplicated GBS strains were collected from clinical samples in Xinhua Hospital, Shanghai, China. Multilocus sequence typing (MLST) method was used for molecular classification, the results were analyzed to derive CCs by Bionumeric 8.0 software. Antibiotic susceptibility test was performed using Vitek-2 Compact system combined with K-B method. Multiplex PCR method was used for serotype identification. A total of 45 virulence genes associated with adhesion, invasion, immune evasion were detected by PCR method and electrophoresis. Three types of features, including antibiotic susceptibility (A), serotypes (S) and virulence genes (V) tests, and XGBoost algorithm was established to develop multi-class CCs identification models. The performance of proposed models was evaluated by the receiver operating characteristic curve (ROC).ResultsThe 325 GBS were divided into 47 STs, and then calculated into 7 major CCs, including CC1, CC10, CC12, CC17, CC19, CC23, CC24. A total of 18 features in three kinds of tests (A, S, V) were significantly different from each CC. The model based on all the features (S&A&V) performed best with AUC 0.9536. The model based on serotype and antibiotic resistance (S&A) only enrolled 5 weighed features, performed well in predicting CCs with mean AUC 0.9212, and had no statistical difference in predicting CC10, CC12, CC17, CC19, CC23 and CC24 when compared with S&A&V model (all p > 0.05).ConclusionsThe S&A model requires least parameters while maintaining a high accuracy and predictive power of CCs prediction. The established model could be used as a promising tool to classify the GBS molecular types, and suggests a substantive improvement in clinical application and epidemiology surveillance in GBS phenotyping.

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Dataset Information

Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element.

Publications

Camel Streptococcus agalactiae populations are associated with specific disease complexes and acquired the tetracycline resistance gene tetM via a Tn916-like element.

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