Search

• Multidrug resistance in important food pathogens abounds. • Antimicrobial potential of extracts of Loxostylis alata was explored. • L. alata reduced bacterial cell attachment and biofilm biomass. • Anti-biofilm activity is an alternative mechanism to overcome bacterial infection. Bacterial biofilms pose health challenges both in clinical environments and the food industry. Major foodborne bacterial pathogens form biofilms on surfaces and persist, causing infections in humans that may be difficult to treat. Conventional use of antibiotics is fast becoming ineffective due to emerging resistance of pathogens to antibiotics. Previous studies have demonstrated the antimicrobial potential of Loxostylis alata A. Spreng. ex Rchb. extracts against a range of bacterial pathogens. The inhibitory effects of methanol and aqueous extracts of L. alata and an antibacterial compound (5-demethyl sinensetin) isolated from the leaves on the growth and development of microbial biofilms was investigated against clinical isolates of Enterobacter cloacae, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis and reference strains of Bacillus cereus, Salmonella Enteritidis and Salmonella Typhimurium using the crystal violet (CV) assay. The Kirby-Bauer disk diffusion method was utilized to determine antibiotic susceptibility and resistance profiles of the four clinical and three reference isolates. E. cloacae was resistant to tetracycline and doxycycline and P. mirabilis was resistant to colistin while E. coli and K. pneumoniae were pan-susceptible to all the antibiotics screened. The hot water extract reduced biofilm adhesion from 7% to >50% for the clinical isolates and the ATCC strains, except for S. Typhimurium. The methanol extract inhibited the growth of preformed biofilms of S. Enteritidis and S. Typhimurium by >50% and also reduced the biofilm biomass in S. Enteritidis and E. coli by >50%. The plant extracts and compound were able to reduce initial cell attachment and biofilm biomass, although inhibition of growth in a preformed biofilm was not attained. [ABSTRACT FROM AUTHOR]

The severity of cashew nut allergy was dichotomized into mild to moderate cashew nut allergy (i.e. oFASS-3 grade 1 and 2) versus severe cashew nut allergy (i.e. oFASS-3 grade 3). Patients with a severe cashew nut allergy tended to have higher median IgE levels against both cashew nut extract and Ana o 3 than patients with mild to moderate cashew nut allergy, but this was not statistically significant ( I p i = .43 vs. I p i = .42, respectively; Figure 2). Keywords: Ana o 3; cashew nut allergy; cashew nut extract; diagnostic value; severity EN Ana o 3 cashew nut allergy cashew nut extract diagnostic value severity 880 882 3 08/14/23 20230801 NES 230801 Key messages We undertook a diagnostic test accuracy study in 43 adults with a suspected cashew nut allergy. [Extracted from the article]

The objectives of this study were to examine the diversity of Staphylococcus spp. recovered from bovine intramammary infections and humans working in close contact with the Animals and to evaluate the susceptibility of the staphylococcal isolates to different antimicrobials. A total of 3,387 milk samples and 79 human nasal swabs were collected from 13 sampling sites in the KwaZulu-Natal province of South Africa. In total, 146 Staph. aureus isolates and 102 coagulase-negative staphylococci (CNS) were recovered from clinical and subclinical milk samples. Staphylococcus aureus was isolated from 12 (15.2%) of the human nasal swabs and 95 representative CNS were recovered for further characterization. The CNS were identified using multiplex- PCR assays, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and tuf gene sequencing. Seven Staphylococcus spp. were identified among the CNS of bovine origin, with Staph. chromogenes (78.4%) predominating. The predominant CNS species recovered from the human nasal swabs was Staph. epidermidis (80%) followed by Staph. chromogenes (6.3%). The antimicrobial susceptibility of all staphylococcal isolates was evaluated using disk diffusion and was supplemented by screening for specific antimicrobial resistance genes. Ninety-eight (67.1%) Staph. aureus isolates of bovine origin were pansusceptible; 39 (26.7%) isolates were resistant to a single class, and 7 (4.8%) isolates were resistant to 2 classes of antimicrobials. Two Staph. aureus (1.4%) isolates were multidrug-resistant. Resistance to penicillin was common, with 28.8% of the bovine and 75% of the human Staph. aureus isolates exhibiting resistance. A similar observation was made with the CNS, where 37.3% of the bovine and 89.5% of the human isolates were resistant to penicillin. Multidrug-resistance was common among the human CNS, with 39% of the isolates exhibiting resistance to 3 or more classes of antimicrobials. The antimicrobial susceptibility results suggest that resistance among staphylococci causing bovine intramammary infections in South Africa is uncommon and not a significant cause for concern. In contrast, antimicrobial resistance was frequently observed in staphylococcal isolates of human origin, highlighting a possible reservoir of resistance genes. Continued monitoring of staphylococcal isolates is warranted to monitor changes in the susceptibility of isolates to different classes of antimicrobials. [ABSTRACT FROM AUTHOR]

Chronic obstructive pulmonary disease (COPD) is characterised by the occurrence of exacerbations triggered by infections. The aim of this study was to determine the composition of the lung microbiome and lung virome in patients with COPD in an African setting and to compare their composition between the stable and exacerbated states. Twenty-four adult COPD patients were recruited from three hospitals. Sputum was collected and bacterial DNA was extracted. Targeted metagenomics was performed to determine the microbiome composition. Viral DNA and RNA were extracted from selected samples followed by cDNA conversion. Shotgun metagenomics sequencing was performed on pooled DNA and RNA. The most abundant phyla across all samples were Firmicutes and Proteobacteria. The following genera were most prevalent: Haemophilus and Streptococcus. There were no considerable differences for alpha and beta diversity measures between the disease states. However, a difference in the abundances between disease states was observed for: (i) Serratia (3% lower abundance in exacerbated state), (ii) Granulicatella (2.2% higher abundance in exacerbated state), (iii) Haemophilus (5.7% higher abundance in exacerbated state) and (iv) Veillonella (2.5% higher abundance in exacerbated state). Virome analysis showed a high abundance of the BeAn 58058 virus, a member of the Poxviridae family, in all six samples (90% to 94%). This study is among the first to report lung microbiome composition in COPD patients from Africa. In this small sample set, no differences in alpha or beta diversity between stable and exacerbated disease state was observed, but an unexpectedly high frequency of BeAn 58058 virus was observed. These observations highlight the need for further research of the lung microbiome of COPD patients in African settings. [ABSTRACT FROM AUTHOR]

Introduction: Klebsiella pneumoniae with OXA-48-like enzymes were introduced into Tshwane Tertiary Hospital (TTH) (Pretoria, South Africa) during September 2015, causing nosocomial outbreaks.Methods: PCR methodologies and WGS were used to characterize K. pneumoniae with carbapenemases (n = 124) from TTH (July 2015-December 2016).Results: PCR was used to track K. pneumoniae ST307 with OXA-181 among 60% of carbapenemase-positive isolates in different wards/units over time and showed the transmission of IncX3 plasmids to other K. pneumoniae clones. WGS identified different ST307 clades: 307_OXA181 (consisting of two lineages, A and B) with OXA-181 on IncX3 plasmids (named p72_X3_OXA181) and clade 307_VIM with VIM-1 on IncFII plasmids. Clade 307_OXA181 lineage B was responsible for the rapid increase and transmission of OXA-181 K. pneumoniae in various wards/units throughout TTH, while the numbers of clade 307_OXA181 lineage A and clade 307_VIM remained low. Separate outbreaks were due to K. pneumoniae ST17 and ST29 with p72_X3_OXA181 plasmids.Conclusions: The high-risk clone K. pneumoniae ST307 with OXA-181 rapidly spread to different wards/units despite infection and prevention measures. ST307 clades and lineages seemingly acted differently in outbreak situations. This study also highlighted the threat of promiscuous plasmids such as p72_X3_OXA181. [ABSTRACT FROM AUTHOR]

Abstract: This study was designed to characterize extended-spectrum beta-lactamase (ESBL)–producing extra-intestinal pathogenic Escherichia coli (E.coli) (ExPEC) associated with urinary tract infections in nine different geographic regions of Zimbabwe over a 2-year period (2017–2019). A total of 48 ESBL-positive isolates from urine specimen were selected for whole-genome sequencing from 1246 Escherichia coli isolates biobanked at the National Microbiology Reference laboratory using phenotypic susceptibility testing results from the National Escherichia coli Surveillance Programme to provide representation of different geographical regions and year of isolation. The majority of ESBL E. coli isolates produced cefotaximase-Munich (CTX-M)-15, CTX-M-27, and CTX-M-14. In this study, sequence types (ST) 131 and ST410 were the most predominant antimicrobial-resistant clones and responsible for the increase in ESBL–producing E. coli strains since 2017. Novel ST131 complex strains were recorded during the period 2017 to 2018, thus showing the establishment and evolution of this antimicrobial-resistant ESBL clone in Zimbabwe posing an important public health threat. Incompatibility group F plasmids were predominant among ST131 and ST410 isolates with the following replicons recorded most frequently: F1:A2:B20 (9/19, 47%), F2:A1: B (5/19, 26%), and F1:A1:B49 (8/13, 62%). The results indicate the need for continuous tracking of different ESBL ExPEC clones on a global scale, while targeting specific STs (e.g. ST131 and ST410) through control programs will substantially decrease the spread of ESBLs among ExPEC. [ABSTRACT FROM AUTHOR]