ABSTRACT
Investment in Africa over the past year with regards to SARS-CoV-2 genotyping has led to a massive increase in the number of sequences, exceeding 100,000 genomes generated to track the pandemic on the continent. Our results show an increase in the number of African countries able to sequence within their own borders, coupled with a decrease in sequencing turnaround time. Findings from this genomic surveillance underscores the heterogeneous nature of the pandemic but we observe repeated dissemination of SARS-CoV-2 variants within the continent. Sustained investment for genomic surveillance in Africa is needed as the virus continues to evolve, particularly in the low vaccination landscape. These investments are very crucial for preparedness and response for future pathogen outbreaks. One-Sentence SummaryExpanding Africa SARS-CoV-2 sequencing capacity in a fast evolving pandemic.
ABSTRACT
The prevalence of plasmid-mediated quinolone resistance (PMQR) determinants was investigated in a Tunisian collection of 300 uropathogenic Escherichia coli. PMQR genes were detected in 68 isolates (22.7%) as follows: aac(6')-Ib-cr (n=66), qnrB1 (n=3), qnrA6 (n=1), and qnrS1 (n=1). Three isolates carried the 2 determinants aac(6')-Ib-cr and qnrB1. aac(6')-Ib-cr was usually carried on IncF-type plasmids (n=47/60) and frequently associated with blaCTX-M-15 (n=60). Substitutions in gyrA and parC genes were detected in 57.5% of strains. A major cluster including 29 isolates was individualized, 28 of them belonged to the virulent ST131 clone. In our hospital, the high prevalence of PMQR in E. coli isolates was due to horizontal transfer but also to the spread of ST131 clone.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Bacterial , Escherichia coli Infections/epidemiology , Quinolones/pharmacology , Uropathogenic Escherichia coli/drug effects , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Cluster Analysis , Escherichia coli Infections/microbiology , Female , Genes, Bacterial , Hospitals, University , Humans , Infant , Male , Middle Aged , Molecular Epidemiology , Molecular Typing , Plasmids/analysis , Prevalence , Tunisia/epidemiology , Uropathogenic Escherichia coli/classification , Uropathogenic Escherichia coli/genetics , Uropathogenic Escherichia coli/isolation & purification , Virulence Factors/genetics , Young AdultABSTRACT
BACKGROUND: The spread of MRSA strains at hospitals as well as in the community are of great concern worldwide. We characterized the MRSA clones isolated at Tunisian hospitals and in the community by comparing them to those isolated in other countries. RESULTS: We characterized 69 MRSA strains isolated from two Tunisian university hospitals between the years 2004-2008. Twenty-two of 28 (79%) community-associated MRSA (CA-MRSA) strains and 21 of 41 (51%) healthcare-associated MRSA (HA-MRSA) strains were PVL-positive. The PVL-positive strains belonged to predicted founder group (FG) 80 in MLST and carried either type IVc SCCmec or nontypeable SCCmec that harbours the class B mec gene complex. In contrast, very diverse clones were identified in PVL-negative strains: three FGs (5, 15, and 22) for HA-MRSA strains and four FGs (5, 15, 45, and 80) for CA-MRSA strains; and these strains carried the SCCmec element of either type I, III, IVc or was nontypeable. The nucleotide sequencing of phi7401PVL lysogenized in a CA-MRSA strain JCSC7401, revealed that the phage was highly homologous to phiSA2mw, with nucleotide identities of more than 95%. Furthermore, all PVL positive strains were found to carry the same PVL phage, since these strains were positive in two PCR studies, identifying gene linkage between lukS and mtp (major tail protein) and the lysogeny region, both of which are in common with phi7401PVL and phiSa2mw. CONCLUSIONS: Our experiments suggest that FG80 S. aureus strains have changed to be more virulent by acquiring phi7401PVL, and to be resistant to ß-lactams by acquiring SCCmec elements. These novel clones might have disseminated in the Tunisian community as well as at the Tunisian hospitals by taking over existing MRSA clones.
