Medical Microbiology
http://hdl.handle.net/2263/1753
2024-03-19T05:32:44ZCharacterization of Salmonella enterica serovar Isangi from South Africa, 2020–2021
http://hdl.handle.net/2263/95244
Characterization of Salmonella enterica serovar Isangi from South Africa, 2020–2021
Myataza, Asive; Thomas, Juno; Smith, Anthony M.
BACKGROUND : We describe the genotypic characteristics and antimicrobial resistance (AMR) determinants of Salmonella
enterica serovar Isangi (Salmonella Isangi) clinical isolates in South Africa from 2020 through 2021.
METHODS : During the years 2020 to 2021, the Centre for Enteric Diseases of the National Institute for Communicable
Diseases, a national reference centre in South Africa for human infections resulting from enteric bacterial pathogens,
investigated a total of 3549 clinical isolates of Salmonella species. Whole genome sequencing (WGS) was performed
using Illumina NextSeq Technology. WGS data was analyzed using Centre for Genomic Epidemiology-based tools
and EnteroBase web-based platform. Genotypic relatedness and cluster analysis was investigated based on coregenome
multilocus sequence typing.
RESULTS : Forty-nine isolates were confirmed to be Salmonella Isangi, with most submitted from Gauteng Province
(24/49, 49%). The most prevalent sequence type was ST335 (48/49, 98%), and the remaining 1 isolate was ST216. All
ST335 isolates were genotypically multidrug-resistant (MDR), with resistance to fluoroquinolones, chloramphenicol,
trimethoprim-sulfamethoxazole and tetracycline; the ST216 isolate was resistant only to aminoglycosides. All ST335
isolates carried ESBL genes, the most common being blaCTX-M-15. Five clusters (consisting of isolates related within five
allele differences) were detected, all being ST335.
CONCLUSIONS : Most Salmonella Isangi isolates in South Africa are MDR and ESBL-positive. Ongoing monitoring
of the epidemiology and AMR profile of this serovar is important for public health and treatment guidelines.
AVAILABILITY OF DATA AND MATERIALS : All sequencing data were uploaded to the public EnteroBase platform (http://
enter obase. warwi ck. ac. uk/ speci es/ index/ sente rica) and so are freely available
to access at the EnteroBase platform. In addition, sequencing data are deposited
in the European Nucleotide Archive under the project accession numbers
PRJEB39546 and PRJEB39988.; SUPPLEMENTARY INFORMATION : Map of South Africa, showing the different provinces of the country. Provinces (regions) are indicated in different colors.
2023-11-01T00:00:00ZMolecular investigations of Mycobacterium tuberculosis genotypes among baseline and follow-up strains circulating in four regions of Eswatini
http://hdl.handle.net/2263/95243
Molecular investigations of Mycobacterium tuberculosis genotypes among baseline and follow-up strains circulating in four regions of Eswatini
Dlamini, Talent C.; Mkhize, Brenda T.; Sydney, Clive; Maningi, Nontuthuko E.; Malinga, Lesibana Anthony
BACKGROUND : The tuberculosis (TB) epidemic remains a major global health problem and Eswatini is not excluded.
Our study investigated the circulating genotypes in Eswatini and compared them at baseline (start of treatment)
and follow-up during TB treatment.
METHODS : Three hundred and ninety (n = 390) participants were prospectively enrolled from referral clinics
and patients who met the inclusion criteria, were included in the study. A total of 103 participants provided specimens
at baseline and follow-up within six months. Mycobacterium tuberculosis (M.tb) strains were detected by GeneXpert
® MTB/RIF assay (Cephied, USA) and Ziehl -Neelsen (ZN) microscopy respectively at baseline and follow-up
time-points respectively. The 206 collected specimens were decontaminated and cultured on BACTEC™ MGIT™
960 Mycobacteria Culture System (Becton Dickinson, USA). Drug sensitivity testing was performed at both baseline
and follow-up time points. Spoligotyping was performed on both baseline and follow-up strains after DNA extraction.
RESULTS : Resistance to at least one first line drug was detected higher at baseline compared to follow-up specimens
with most of them developing into multidrug-resistant (MDR)-TB. A total of four lineages and twenty genotypes were
detected. The distribution of the lineages varied among the different regions in Eswatini. The Euro-American lineage
was the most prevalent with 46.12% (95/206) followed by the East Asian with 24.27% (50/206); Indo-Oceanic at 9.71%
(20/206) and Central Asian at 1.94% (4/206). Furthermore, a high proportion of the Beijing genotype at 24.27%
(50/206) and S genotype at 16.50% (34/206) were detected. The Beijing genotype was predominant in follow-up
specimens collected from the Manzini region with 48.9% (23/47) (p = 0.001). A significant proportion of follow-up
specimens developed MDR-TB (p = 0.001) with Beijing being the major genotype in most follow-up specimens
(p < 0.000).
CONCLUSION : Eswatini has a high M.tb genotypic diversity. A significant proportion of the TB infected participants
had the Beijing genotype associated with MDR-TB in follow-up specimens and thus indicate community wide
transmission.
AVAILABILITY OF DATA AND MATERIALS : The datasets used and/or analysed during the current study are available from
the corresponding author on reasonable request.; SUPPLEMENTARY MATERIAL. Baseline findings. SUPPLEMENTARY MATERIAL. Follow-up findings.
2023-08-29T00:00:00ZPopulation-based genomic surveillance of Pseudomonas aeruginosa causing bloodstream infections in a large Canadian health region
http://hdl.handle.net/2263/95193
Population-based genomic surveillance of Pseudomonas aeruginosa causing bloodstream infections in a large Canadian health region
Peirano, Gisele; Matsumara, Yasufumi; Nobrega, Diego; Church, Deirdre; Pitout, Johann D.D.
Please read abstract in the article.
DATA AVAILABILITY : Sequence data was uploaded to NCBI (BioProject PRJNA988909).; CODE AVAILABILITY : Sequence data is available at NCBI (BioProject PRJNA988909).
2024-03-01T00:00:00ZPotential for maternally administered vaccine for infant group B streptococcus
http://hdl.handle.net/2263/94684
Potential for maternally administered vaccine for infant group B streptococcus
Madhi, Shabir A.; Anderson, Annaliesa S.; Absalon, Judith; Radley, David; Simon, Raphael; Jongihlati, Babalwa; Strehlau, Renate; Van Niekerk, Anika M.; Izu, Alane; Naidoo, Niree; Kwatra, Gaurav; Ramsamy, Yogandree; Said, Mohamed; Jones, Stephanie; Jose, Lisa; Fairlie, Lee; Barnabas, Shaun L.; Newton, Ryan; Munson, Samantha; Jefferies, Zahra; Pavliakova, Danka; Silmon de Monerri, Natalie C.; Gomme, Emily; Perez, John L.; Scott, Daniel A.; Gruber, William C.; Jansen, Kathrin U.
BACKGROUND : Natural history studies have correlated serotype-specific anti–capsular polysaccharide (CPS) IgG in newborns with a reduced risk of group B streptococcal disease. A hexavalent CPS–cross-reactive material 197 glycoconjugate vaccine (GBS6) is being developed as a maternal vaccine to prevent invasive group B streptococcus in young infants.
METHODS : In an ongoing phase 2, placebo-controlled trial involving pregnant women, we assessed the safety and immunogenicity of a single dose of various GBS6 formulations and analyzed maternally transferred anti-CPS antibodies. In a parallel seroepidemiologic study that was conducted in the same population, we assessed serotype-specific anti-CPS IgG concentrations that were associated with a reduced risk of invasive disease among newborns through 89 days of age to define putative protective thresholds.
RESULTS : Naturally acquired anti-CPS IgG concentrations were associated with a reduced risk of disease among infants in the seroepidemiologic study. IgG thresholds that were determined to be associated with 75 to 95% reductions in the risk of disease were 0.184 to 0.827 μg per milliliter. No GBS6-associated safety signals were observed among the mothers or infants. The incidence of adverse events and of serious adverse events were similar across the trial groups for both mothers and infants; more local reactions were observed in the groups that received GBS6 containing aluminum phosphate. Among the infants, the most common serious adverse events were minor congenital anomalies (umbilical hernia and congenital dermal melanocytosis). GBS6 induced maternal antibody responses to all serotypes, with maternal-to-infant antibody ratios of approximately 0.4 to 1.3, depending on the dose. The percentage of infants with anti-CPS IgG concentrations above 0.184 μg per milliliter varied according to serotype and formulation, with 57 to 97% of the infants having a seroresponse to the most immunogenic formulation.
CONCLUSIONS : GBS6 elicited anti-CPS antibodies against group B streptococcus in pregnant women that were transferred to infants at levels associated with a reduced risk of invasive group B streptococcal disease.
2023-07-01T00:00:00Z