Abstract South Africa’s fourth COVID-19 wave was driven predominantly by three lineages (BA.1, BA.2 and BA.3) of the SARS-CoV-2 Omicron variant of concern. We have now identified two new lineages, BA.4 and BA.5. The spike proteins of BA.4 and BA.5 are identical, and comparable to BA.2 except for the addition of 69-70del, L452R, F486V and the wild type amino acid at Q493. The 69-70 deletion in spike allows these lineages to be identified by the proxy marker of S-gene target failure with the TaqPath™ COVID-19 qPCR assay. BA.4 and BA.5 have rapidly replaced BA.2, reaching more than 50% of sequenced cases in South Africa from the first week of April 2022 onwards. Using a multinomial logistic regression model, we estimate growth advantages for BA.4 and BA.5 of 0.08 (95% CI: 0.07 - 0.09) and 0.12 (95% CI: 0.09 - 0.15) per day respectively over BA.2 in South Africa.
Abstract The SARS-CoV-2 epidemic in southern Africa has been characterized by three distinct waves. The first was associated with a mix of SARS-CoV-2 lineages, while the second and third waves were driven by the Beta (B.1.351) and Delta (B.1.617.2) variants, respectively 1–3 . In November 2021, genomic surveillance teams in South Africa and Botswana detected a new SARS-CoV-2 variant associated with a rapid resurgence of infections in Gauteng province, South Africa. Within three days of the first genome being uploaded, it was designated a variant of concern (Omicron, B.1.1.529) by the World Health Organization and, within three weeks, had been identified in 87 countries. The Omicron variant is exceptional for carrying over 30 mutations in the spike glycoprotein, which are predicted to influence antibody neutralization and spike function 4 . Here we describe the genomic profile and early transmission dynamics of Omicron, highlighting the rapid spread in regions with high levels of population immunity.
Patients already colonized with multidrug-resistant (MDR) Gram-negative bacteria (GNB) on admission to critical care units may be an important source of transmission of these bacteria in hospitals. We sought to determine the prevalence of MDR GNB colonization in patients, staff and the ward environment and to assess the risk factors for colonization of patients in wards.The study was conducted from April 2021 to July 2021 in a teaching hospital in Ghana. MDR GNB were isolated from rectal, and hand swabs were taken from patients on admission and after 48 h. Swabs from HCW's hands and the ward environment were also taken. Risk factors for colonization with MDR GNB were assessed using univariate and multivariate analysis.MDR GNB rectal colonization rate among patients was 50.62% on admission and 44.44% after 48 h. MDR GNB were isolated from 6 (5.26%) and 24 (11.54%) of HCW's hand swabs and environmental swabs, respectively. Previous hospitalization (p-value = 0.021, OR, 95% CI= 7.170 (1.345-38.214) was significantly associated with colonization by MDR GNB after 48 h of admission. Age (21-30 years) (p-value = 0.022, OR, 95% CI = 0.103 (0.015-0.716) was significantly identified as a protective factor associated with a reduced risk of rectal MDR GNB colonization.The high colonization of MDR GNB in patients, the carriage of MDR GNB on HCW's hands, and the contamination of hospital environments highlights the need for patient screening and stringent infection prevention and control practices to prevent the spread of MDR GNB in hospitals.
ObjectivesThis study delineated the clonal lineages, antibiotic resistome and plasmid replicon types in multidrug-resistant K. pneumoniae isolates from a teaching hospital in Ghana.MethodsIdentification and antibiotic susceptibility testing were done using the MALDI-TOF MS and Vitek-2 automated system. Genomic DNA extraction was carried out using the NucliSens easyMAG® (BioMérieux) kits and the DNA was subjected to whole genome sequencing (WGS) using the Illumina MiSeq platform.ResultsOf the 200 isolates obtained, 37 were identified as K. pneumoniae of which 9 were resistant to all second and third-generation cephalosporins. These 9 isolates selected for further genomic analysis were characterized by the presence of 8 diverse sequence types (STs), capsular polysaccharide serotypes (K types and wzi allelic types) and multiple genes encoding resistance to β-lactams (blaCTX-M-15, blaSHV-11, blaTEM-1B, blaOXA-1), aminoglycosides (aac(3)-IIa, strB, strA, aadA16), fluoroquinolones/quinolones (qnrB66, oqxA, oqxB) and other antibiotic classes. Resistance genes were associated with plasmids, predominantly IncFIB(K) and ColRNAI. Multiple and diverse mutations in quinolone resistance-determining regions of gyrA (S83Y, D87A) and parC (S80I, N304S) in isolates resistant to ciprofloxacin (MIC ≥ 4 mg/mL) were found. Global phylogenomic analysis affirmed the diverse clonal clustering and origin of these isolates.ConclusionsThe varied clonal clusters and resistome identified in the multidrug-resistant K. pneumoniae isolates is a major threat to the management of infections in Ghana. The molecular characterization of antibiotic resistance is thus imperative to inform strategies for containment.
The underlying resistance mechanisms, defence systems, mobilome, virulome, clonality and global phylogenetic relationship of a novel sequence type (ST) 658 Aeromonas hydrophilia (A34a) isolated from a pig abattoir in South Africa was determined using whole-genome sequence (WGS) technology.Following isolation on chromogenic agar (CHROMID® CARBA SMART), microbial identification and antibiotic susceptibility testing were performed using a VITEK®2 platform. Genotyping involved WGS performed with an Illumina MiSeq platform.The antibiotic resistome agreed with the resistance phenotype of the isolate and included antibiotic resistance determinants for β-lactams (blaCPHA3 and blaOXA-724). BLASTn analysis of resistome-encoding contigs affirmed chromosomally-mediated resistance. BURST algorithmic analysis identified the novel ST658 as a satellite variant. Virulome analysis predicted virulence genes of Aeromonas whose expression are critical for establishing infection in the host. Global phylogenomic analyses showed strain A34a is closely related to two international isolates from Sri Lanka (Ae25) and the USA (RU34A), although there is little to suggest that it was imported from abroad.This is the first report on the genomic analysis of a novel ST658 A. hydrophilia, offering useful insights into its pathogenicity and global phylogenetics.
Enterococci are among the most common opportunistic hospital pathogens. This study used whole-genome sequencing (WGS) and bioinformatics to determine the antibiotic resistome, mobile genetic elements, clone and phylogenetic relationship of
The worldwide proliferation of life-threatening metallo-β-lactamase (MBL)-producing Gram-negative bacteria is a serious concern to public health. MBLs are compromising the therapeutic efficacies of β-lactams, particularly carbapenems, which are last-resort antibiotics indicated for various multidrug-resistant bacterial infections.
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