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result(s) for
"Lowe, Michelle"
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Outbreak of NDM-1– and OXA-181–Producing Klebsiella pneumoniae Bloodstream Infections in a Neonatal Unit, South Africa
by
Dennis, Tanya
,
Lowe, Michelle
,
Bore, Abram
in
Analysis
,
Anti-Bacterial Agents - pharmacology
,
Anti-Bacterial Agents - therapeutic use
2023
After an increase in carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections and associated deaths in the neonatal unit of a South Africa hospital, we conducted an outbreak investigation during October 2019-February 2020 and cross-sectional follow-up during March 2020-May 2021. We used genomic and epidemiologic data to reconstruct transmission networks of outbreak-related clones. We documented 31 cases of culture-confirmed CRKP infection and 14 deaths. Two outbreak-related clones (bla
sequence type [ST] 152 [n = 16] and bla
ST307 [n = 6]) cocirculated. The major clone bla
ST152 accounted for 9/14 (64%) deaths. Transmission network analysis identified possible index cases of bla
ST307 in October 2019 and bla
ST152 in November 2019. During the follow-up period, 11 new cases of CRKP infection were diagnosed; we did not perform genomic analysis. Sustained infection prevention and control measures, adequate staffing, adhering to bed occupancy limits, and antimicrobial stewardship are key interventions to control such outbreaks.
Journal Article
Diversity of SCCmec elements and spa types in South African Staphylococcus aureus mecA-positive blood culture isolates
by
Mogokotleng, Ruth
,
Lowe, Michelle
,
Perovic, Olga
in
Antibiotics
,
Antiinfectives and antibacterials
,
Antimicrobial agents
2020
Background
The prevalence of
Staphylococcus aureus
varies depending on the healthcare facility, region and country. To understand its genetic diversity, transmission, dissemination, epidemiology and evolution in a particular geographical location, it is important to understand the similarities and variations in the population being studied. This can be achieved by using various molecular characterisation techniques. This study aimed to provide detailed molecular characterisation of South African
mec
A-positive
S. aureus
blood culture isolates by describing the SCC
mec
types,
spa
types and to lesser extent, the sequence types obtained from two consecutive national surveillance studies.
Methods
S. aureus
blood culture isolates from a national laboratory-based and enhanced surveillance programme were identified and antimicrobial susceptibility testing was performed using automated systems. A real-time PCR assay confirmed the presence of the methicillin-resistance determinant,
mec
A. Conventional PCR assays were used to identify the SCC
mec
type and
spa
type, which was subsequently analysed using the Ridom StaphType™ software. Multilocus sequence typing was performed on selected isolates using conventional methods. MRSA clones were defined by their sequence type (ST), SCC
mec
type and
spa
type.
Results
A detailed description of findings is reported in this manuscript. SCC
mec
type III predominated overall followed by type IV. A total of 71 different
spa
types and 24 novel
spa
types were observed.
Spa
type t037 was the most common and predominated throughout followed by t1257. Isolates were multidrug resistant; isolates belonging to all SCC
mec
types were resistant to most of the antibiotics with the exception of type I; isolates with
spa
type t045 showed resistance to all antibiotics except vancomycin. The most diverse SCC
mec
-
spa
type complex was composed of the SCC
mec
type IV element and 53 different
spa
types.
Conclusion
Although ST data was limited, thereby limiting the number of clones that could be identified, the circulating clones were relatively diverse.
Journal Article
Ward-specific clustering of methicillin-resistant Staphylococcus aureus spa-type t037 and t045 in two hospitals in South Africa: 2013 to 2017
by
Ismail, Arshad
,
Kwanda, Stanford
,
Lowe, Michelle
in
Antimicrobial agents
,
Antimicrobial resistance
,
Biology and life sciences
2021
Methicillin-resistant Staphylococcus aureus (MRSA) is a highly clonal pathogen causing infections in various settings. The aim of this study was to determine if healthcare-associated (HA) MRSA isolates with the same spa-type originating from two geographically distinct hospitals in South Africa were genetically related based on PFGE. Furthermore, a small subset of MRSA isolates were characterised with WGS and then compared to PFGE to determine if PFGE is still a reliable method to define outbreaks and/or transmission chains. Staphylococcus aureus isolated from blood cultures (BC) were submitted to the Centre for Healthcare-Associated Infections, Antimicrobial Resistance and Mycoses (CHARM) as part of a laboratory-based surveillance programme (GERMS-SA). The identified HA-MRSA isolates underwent molecular characterisation [Staphylococcal Chromosome Cassette (SCC) mec and spa-typing]. Pulsed-field gel electrophoresis (PFGE) was performed on selected isolates with the same spa-type. Twenty-one MRSA isolates were selected for whole-genome sequencing (WGS) based on spa-type, PFGE clustering, time and place of isolation. Eighteen percent (n = 95/529) and 33% (n = 234/710) of isolates collected, from two public tertiary academic hospitals in the Gauteng (GAU) and the Western Cape (WC) provinces, were identified as MRSA, respectively. The most dominant clone in the GAU hospital was t037-III-MRSA (43.2%; n = 41/95). The most dominant clones in the WC hospital was t037-III-MRSA (23.9%, n = 56/234) and t045-I-MRSA (23.5%, n = 55/234). The GAU-t037-III-MRSA cases and WC-t045-I-MRSA cases occurred in the paediatric patient population, whereas the WC-t037-III-MRSA cases occurred in the adult patient population. A novel spa-type (t19935) was detected in the GAU hospital. PFGE showed that the GAU- and WC-t037-III-MRSA isolates were genetically indistinguishable, as well as most of the WC-t045-I-MRSA isolates. The Vienna/Hungarian/Brazilian clone and British EMRSA-3 clone were in circulation and a low frequency of single nucleotide polymorphisms (SNP) ([less than or equal to]20) differences was observed among isolates with the same spa-type. The low number of SNP differences is suggestive of uninterrupted strain transmission and the persistence of t037-III-MRSA and t045-I-MRSA from 2013 to 2017 in the two studied hospitals. Alternative infection prevention and control strategies should be considered to supplement control efforts.
Journal Article
In Vitro Activity of Ceftolozane-Tazobactam against Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa Obtained from Blood Cultures from Sentinel Public Hospitals in South Africa
by
Perovic, Olga
,
Lowe, Michelle
,
Singh-Moodley, Ashika
in
Amides
,
Aminoglycoside antibiotics
,
Aminoglycosides
2023
Multidrug-resistant (MDR) Gram-negative bacteria are responsible for the majority of healthcare-associated infections and pose a serious threat as they complicate and prolong clinical care. A novel cephalosporin-β-lactamase-inhibitor combination, ceftolozane-tazobactam (C/T) was introduced in 2014, which improved the treatment of MDR pathogens. This study aimed to evaluate the activity of C/T against Escherichia coli (n = 100), Klebsiella pneumoniae (n = 100), and Pseudomonas aeruginosa (n = 100) blood culture isolates in South Africa (SA). Isolates were sequentially selected (2010 to 2020) from the Group for Enteric, Respiratory, and Meningeal Diseases Surveillance (GERMS) programme in SA. Organism identification was performed using the matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF MS) instrument (Microflex, Bruker Daltonics, Bremen, Germany), and antibiotic susceptibility was performed using the Sensititre instrument (Trek Diagnostic Systems, East Grinstead, UK). C/T resistance was reported in 16 E. coli, 28 K. pneumoniae and 13 P. aeruginosa isolates. Fifty percent of the C/T resistant isolates were subjected to whole-genome sequencing (WGS). According to the whole genome multilocus sequence typing (MLST) analysis, the E. coli isolates (n = 8) belonged to sequence type (ST)10, ST131, ST405, and ST410, the K. pneumoniae isolates (n = 14) belonged to ST1, ST37, ST73, ST101, ST231, ST307, ST336 and ST6065 (novel ST), and the P. aeruginosa isolates (n = 7) belonged to ST111, ST233, ST273, and ST815. The WGS data also showed that all the E. coli isolates harboured aminoglycoside (aph (3′′)-Ib, aph (6)-Id), macrolide (mdfA, mphA), and sulphonamide (sul2) antibiotic resistance genes, all the K. pneumoniae isolates harboured β-lactam (blaCTX-M-15), and sulphonamide (sul2) antibiotic resistance genes, and all the P. aeruginosa isolates harboured aminoglycoside (aph (3′)-IIb), β-lactam (PAO), fosfomycin (fosA), phenicol (catB7), quinolone (crpP), and disinfectant (qacE) antibiotic resistance genes. It is evident that E. coli, K. pneumoniae and P. aeruginosa can adapt pre-existing resistance mechanisms to resist newer β-lactam molecules and inhibitors, since these isolates were not exposed to ceftolozane-tazobactam previously.
Journal Article
Acinetobacter baumannii complex, national laboratory-based surveillance in South Africa, 2017 to 2019
by
Lowe, Michelle
,
Jallow, Sabelle
,
Perovic, Olga
in
Acinetobacter baumannii
,
Analysis
,
Antibiotics
2022
We aimed to provide an analysis of A. baumannii complex (ABC) isolated from blood cultures in South Africa. ABC surveillance was conducted from 1 April 2017 to 30 September 2019 at 19 hospital sites from blood cultures of any age and sex. Organism identification was performed using the MALDI-TOF MS and antimicrobial susceptibility testing (AST), MicroScan Walkaway System. We confirmed colistin resistance with Sensititre, FRCOL panel, and selected for whole-genome sequencing. During the study period, we identified 4822 cases of ABC, of which 2152 cases were from 19 enhanced surveillance sites were reported during the enhanced surveillance period (1 August 2018 to 30 September 2019). Males accounted for 54% (2611/4822). Of the cases with known age, 41% (1968/4822) were infants (< 1-year-old). Seventy-eight percent (1688/2152) of cases had a known hospital outcome, of which 36% (602/1688) died. HIV status was known for 69% (1168/1688) of cases, and 14% (238/1688) were positive. Eighty-two percent (1389/1688) received antimicrobial treatment in admission. Three percent (35/1389) of cases received single colistin. Four percent (75/2033) were resistant to colistin. At least 75% of the isolates (1530/2033) can be classified as extensively drug-resistant (XDR), with resistance to most antibiotics except for colistin. The majority, 83% (20/24), of the colistin-resistant isolates were of the sequence type (ST) 1. Resistance genes, both plasmid- and chromosomal- mediated were not observed. Although all isolates had, nine efflux pump genes related to antimicrobial resistance. Our surveillance data contributed to a better understanding of the natural course of A. baumannii disease, the patient characteristics among infants, and the level of resistance. At least two-thirds of the isolates were extensively drug-resistant, and four percent of isolates were resistant to colistin.
Journal Article
Bacterial and genetic features of raw retail pork meat : integrative analysis of antibiotic susceptibility, whole-genome sequencing, and metagenomics
by
Lowe, Michelle
,
Perovic, Olga
,
Strasheim, Wilhelmina
in
Amides
,
Animals
,
antibiotic residue testing
2024
The global antibiotic resistance crisis, driven by overuse and misuse of antibiotics, is multifaceted. This study aimed to assess the microbiological and genetic characteristics of raw retail pork meat through various methods, including the isolation, antibiotic susceptibility testing (AST), wholegenome sequencing (WGS) of selected indicator bacteria, antibiotic residue testing, and metagenomic sequencing. Samples were purchased from 10 pre-selected retail stores in Gauteng, South Africa. The samples were aseptically separated, with portions sent to an external laboratory for isolating indicator bacteria and testing for antibiotic residues. Identification of the isolated bacteria was reconfirmed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). AST was performed using the Microscan Walkaway system (Beckman Coulter, Brea, CA, USA). WGS and metagenomic sequencing were performed using the Illumina NextSeq 550 instrument (San Diego, CA, USA). The isolated E. coli and E. faecalis exhibited minimal phenotypic resistance, with WGS revealing the presence of tetracycline resistance genes. Both the isolated bacteria and meat samples harboured tetracycline resistance genes and the antibiotic residue concentrations were within acceptable limits for human consumption. In the metagenomic context, most identified bacteria were of food/meat spoilage and environmental origin. The resistome analysis primarily indicated beta-lactam, tetracycline and multidrug resistance genes. Further research is needed to understand the broader implications of these findings on environmental health and antibiotic resistance.
Journal Article
Whole-genome sequencing of human and porcine Escherichia coli isolates on a commercial pig farm in South Africa
by
Lowe, Michelle
,
Etter, Eric M. C.
,
Smith, Anthony M.
in
Animals
,
Antibiotic resistance
,
Antibiotics
2024
Escherichia coli is an indicator micro-organism in One Health antibiotic resistance surveillance programs. The purpose of the study was to describe and compare E. coli isolates obtained from pigs and human contacts from a commercial farm in South Africa using conventional methods and whole-genome sequencing (WGS). Porcine E. coli isolates were proportionally more resistant phenotypically and harbored a richer diversity of antibiotic resistance genes as compared to human E. coli isolates. Different pathovars, namely ExPEC (12.43%, 21/169), ETEC (4.14%, 7/169), EPEC (2.96%, 5/169), EAEC (2.96%, 5/169) and STEC (1.18%, 2/169), were detected at low frequencies. Sequence type complex (STc) 10 was the most prevalent (85.51%, 59/169) among human and porcine isolates. Six STcs (STc10, STc86, STc168, STc206, STc278 and STc469) were shared at the human–livestock interface according to multilocus sequence typing (MLST). Core-genome MLST and hierarchical clustering (HC) showed that human and porcine isolates were overall genetically diverse, but some clustering at HC2–HC200 was observed. In conclusion, even though the isolates shared a spatiotemporal relationship, there were still differences in the virulence potential, antibiotic resistance profiles and cgMLST and HC according to the source of isolation.
Journal Article
An outbreak of cutaneous abscesses caused by Panton-Valentine leukocidin-producing methicillin-susceptible Staphylococcus aureus among gold mine workers, South Africa, November 2017 to March 2018
by
Naicker, Serisha
,
Lowe, Michelle
,
De Abreu, Cecilia
in
Abscess
,
Abscesses
,
Antimicrobial agents
2020
Background
We aimed to describe an outbreak of cutaneous abscesses caused by Panton-Valentine leukocidin (PVL)-producing methicillin-susceptible
Staphylococcus aureus
(MSSA) among gold mine workers.
Methods
In February 2018, we retrospectively reviewed a random sample of 50 medical records from 243 cases and conducted face-to-face interviews using a structured questionnaire. Pus aspirates were sent to the National Institute for Communicable Diseases from prospectively-identified cases (November 2017–March 2018). Nasopharyngeal swabs were collected during a colonisation survey in February 2018.
Staphylococcus aureus
isolates were screened with a conventional PCR for
lukS/F
-PV. Pulsed-field gel electrophoresis (PFGE) was performed to determine the genetic relatedness among the isolates. A sample of isolates were selected for whole genome sequencing (WGS). We conducted an assessment on biological risks associated with mining activities.
Results
From January 2017 to February 2018, 10% (350/3582) of mine workers sought care for cutaneous abscesses. Forty-seven medical files were available for review, 96% were male (
n
= 45) with a mean age of 43 years (SD = 7). About 52% (24/46) were involved in stoping and 28% (13/47) worked on a particular level. We cultured
S. aureus
from 79% (30/38) of cases with a submitted specimen and 14% (12/83) from colonisation swabs. All isolates were susceptible to cloxacillin. Seventy-one percent of
S. aureus
isolates (30/42) were PVL-PCR-positive. Six PFGE clusters were identified, 57% (21/37) were closely related. WGS analysis found nine different sequence types. PFGE and WGS analysis showed more than one cluster of
S. aureus
infections involving closely related isolates. Test reports for feed and product water of the mine showed that total plate counts were above the limits of 1000 cfu/ml, coliform counts > 10 cfu/100 ml and presence of faecal coliforms. Best practices were poorly implemented as some mine workers washed protective clothing with untreated water and hung them for drying at the underground surface.
Conclusions
PVL-producing MSSA caused an outbreak of cutaneous abscesses among underground workers at a gold mining company. To our knowledge, no other outbreaks of PVL-producing
S. aureus
involving skin and soft tissue infections have been reported in mining facilities in South Africa. We recommend that worker awareness of infection prevention and control practices be strengthened.
Journal Article
Method to Assess Farm-Level Vaccine and Antibiotic Usage Utilizing Financial Documentation: A Pilot Study in a Commercial Pig Farm in South Africa From 2016 to 2018
by
Lowe, Michelle
,
Etter, Eric M. C.
,
Perovic, Olga
in
Agricultural production
,
Agricultural sciences
,
Agriculture
2022
The purpose of the study was to develop a blueprint using financial documentation to describe and quantify vaccine and antibiotic usage (ABU). This method was piloted in a commercial pig farm in South Africa, with the ultimate hope to serve as a tool in a future species-specific vaccine and ABU surveillance system. Data collection was based on templates from the European Surveillance of Veterinary Antimicrobial Consumption (ESVAC) network and the World Organisation for Animal Health (WOAH). Invoices from 2016 to 2018 were used as the main data source. In addition, monthly statement of accounts were used to check for missing invoices. An inventory check was done to ensure that the correct antibiotic concentrations were used in subsequent calculations. Livestock counts and slaughter statistics were also collected to be used as denominator data. Cost calculations for the procurement of antibiotics and vaccines were also done. The study showed that veterinary medicinal products were purchased only from a single veterinary practice. A total of 291 invoices were issued over 3 years, of which 2.75% (8/291) were missing and could therefore not be used in quantification. Tetracyclines (453.65 ± 25.49 kg and 135.16 ± 3.31 mg/kg), followed by quinoxalines (258.33 ± 8.04 kg and 77.07 ± 3.93 mg/kg) were used in the highest amounts, both in terms of weight (kg) and adjusted for animal biomass (mg/kg). Vaccines used on the farm targeted seven different diseases, namely enzootic pneumonia, erysipelas, ileitis, infectious infertility, leptospirosis, neonatal pig diarrhea and porcine circovirus disease. An average of 103 546 vaccine dosages was purchased for ZAR1 302,727 ( $ 84,620 1 ) per year, whereas the average cost for the procurement of antibiotics was ZAR 907,372 ($69,561) per year. The study showed that invoices and monthly statement of accounts, in combination with an inventory check and on-farm production statistics, are useful data sources to quantify vaccine and ABU in the absence of veterinary prescriptions. In addition, vaccinating pigs were more expensive than administering antibiotics.
Journal Article
Self-organizing innovation networks, mobile knowledge carriers and diasporas
by
Williams, Allan M.
,
Cudworth, Katherine
,
Lowe, Michelle S.
in
Business innovation
,
Diaspora
,
Diasporas
2012
This paper provides insights from the UK’s pioneering boutique hotel chain, Hotel du Vin (HduV) to explore the dynamics of self-forming innovation networks within the service sector. In particular, it focuses on HduV’s diaspora of spin-off and follow-on enterprises, examining the nature of innovation and creativity, and the significant role of human mobility in knowledge transfer and in the dynamic reconfiguration of such networks. Through the use of participative’ research methods and ‘close dialogue’, it provides a contribution to understanding processes of innovation in an underresearched industry—utilizing the concept of ‘diasporas’ to encapsulate the temporality and spatiality of those processes. In particular, it explores the various re-uses and re-combinations of the organizational processes and value propositions that defined the innovatory nature of the original chain, showing how those re-combinations were critical to the entrepreneurial nature of the diasporic network which developed around HduV
Journal Article