scholarly journals Genomic epidemiology of Escherichia coli isolates from a tertiary referral center in Lilongwe, Malawi

2020 ◽  
Author(s):  
Gerald Tegha ◽  
Emily J. Ciccone ◽  
Robert Krysiak ◽  
James Kaphatika ◽  
Tarsizio Chikaonda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Type Species ◽  
Tertiary Care ◽  
Sub Saharan Africa ◽  
Resistant Bacteria ◽  
Tertiary Care Centre ◽  
Content Type ◽  
Genomic Epidemiology ◽  
Link Type

Antimicrobial resistance (AMR) is a global threat, including in sub-Saharan Africa. However, little is known about the genetics of resistant bacteria in the region. In Malawi, there is growing concern about increasing rates of antimicrobial resistance to most empirically used antimicrobials. The highly drug resistant Escherichia coli sequence type (ST) 131, which is associated with the extended spectrum β-lactamase blaCTX-M-15 , has been increasing in prevalence globally. Previous data from isolates collected between 2006 and 2013 in southern Malawi have revealed the presence of ST131 and the blaCTX-M-15 gene in the country. We performed whole genome sequencing (WGS) of 58 clinical E. coli isolates at Kamuzu Central Hospital, a tertiary care centre in central Malawi, collected from 2012 to 2018. We used Oxford Nanopore Technologies (ONT) sequencing, which was performed in Malawi. We show that ST131 is observed more often (14.9% increasing to 32.8%) and that the blaCTX-M-15 gene is occurring at a higher frequency (21.3% increasing to 44.8%). Phylogenetics indicates that isolates are highly related between the central and southern geographic regions and confirms that ST131 isolates are contained in a single group. All AMR genes, including blaCTX-M-15 , were widely distributed across sequence types. We also identified an increased number of ST410 isolates, which in this study tend to carry a plasmid-located copy of blaCTX-M-15 gene at a higher frequency than blaCTX-M-15 occurs in ST131. This study confirms the expanding nature of ST131 and the wide distribution of the blaCTX-M-15 gene in Malawi. We also highlight the feasibility of conducting longitudinal genomic epidemiology studies of important bacteria with the sequencing done on site using a nanopore platform that requires minimal infrastructure.

scholarly journals Genomic Epidemiology of Escherichia coli Isolates from a Tertiary Referral Center in Lilongwe, Malawi

2020 ◽  
Author(s):  
Gerald Tegha ◽  
Emily J. Ciccone ◽  
Robert Krysiak ◽  
James Kaphatika ◽  
Tarsizio Chikaonda ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Care Center ◽  
Tertiary Care ◽  
Sub Saharan Africa ◽  
Resistant Bacteria ◽  
Sequencing Data ◽  
Data Repositories ◽  
Genomic Epidemiology ◽  
Public Data

ABSTRACTAntimicrobial resistance (AMR) is a global threat, including in sub-Saharan Africa. However, little is known about the genetics of resistant bacteria in the region. In Malawi, there is growing concern about increasing rates of antimicrobial resistance to most empirically used antimicrobials. The highly drug resistant Escherichia coli sequence type (ST) 131, which is associated with the extended spectrum β-lactamase blaCTX-M-15, has been increasing in prevalence globally. Previous data from isolates collected between 2006-2013 in southern Malawi have shown the presence of ST131 and the blaCTX-M-15 gene in the country. We performed whole genome sequencing (WGS) of 58 clinical E. coli isolates at Kamuzu Central Hospital, a tertiary care center in central Malawi, collected from 2012-2018. We used Oxford Nanopore Technologies (ONT) sequencing, which was performed in Malawi. We show that ST131 has become more prevalent (14.9% increasing to 32.8%) and that the blaCTX-M-15gene is occurring at a higher frequency (21.3% increasing to 44.8%). Phylogenetics show isolates are highly related between the central and southern geographic regions and confirm that ST131 isolates are contained in a single group consistent with recent expansion. All AMR genes, including blaCTX-M-15, were widely distributed across sequence types. We also identified an increased number of ST410 isolates, which in this study tend to carry a plasmid-located copy of blaCTX-M-15 gene at a higher frequency than blaCTX-M-15 occurs in ST131. This study confirms the expanding nature of ST131 and the wide distribution of the blaCTX-M-15 gene in Malawi. We also highlight the feasibility of conducting longitudinal genomic epidemiology studies of important bacteria with the sequencing done on site using a nanopore platform that requires minimal infrastructure.DATA SUMMARYThe sequencing data used for this analysis is available in public data repositories. Information on the sequences used is provided in Supplementary Table 2.

scholarly journals Genomic surveillance of Escherichia coli and Klebsiella spp. in hospital sink drains and patients

2020 ◽  
Vol 6 (7) ◽  
Author(s):  
Bede Constantinides ◽  
Kevin K. Chau ◽  
T. Phuong Quan ◽  
Gillian Rodger ◽  
Monique I. Andersson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Type Species ◽  
Whole Genome ◽  
Content Type ◽  
E Coli ◽  
Link Type ◽  
Antimicrobial Resistance Genes

Escherichia coli and Klebsiella spp. are important human pathogens that cause a wide spectrum of clinical disease. In healthcare settings, sinks and other wastewater sites have been shown to be reservoirs of antimicrobial-resistant E. coli and Klebsiella spp., particularly in the context of outbreaks of resistant strains amongst patients. Without focusing exclusively on resistance markers or a clinical outbreak, we demonstrate that many hospital sink drains are abundantly and persistently colonized with diverse populations of E. coli , Klebsiella pneumoniae and Klebsiella oxytoca , including both antimicrobial-resistant and susceptible strains. Using whole-genome sequencing of 439 isolates, we show that environmental bacterial populations are largely structured by ward and sink, with only a handful of lineages, such as E. coli ST635, being widely distributed, suggesting different prevailing ecologies, which may vary as a result of different inputs and selection pressures. Whole-genome sequencing of 46 contemporaneous patient isolates identified one (2 %; 95 % CI 0.05–11 %) E. coli urine infection-associated isolate with high similarity to a prior sink isolate, suggesting that sinks may contribute to up to 10 % of infections caused by these organisms in patients on the ward over the same timeframe. Using metagenomics from 20 sink-timepoints, we show that sinks also harbour many clinically relevant antimicrobial resistance genes including bla CTX-M, bla SHV and mcr, and may act as niches for the exchange and amplification of these genes. Our study reinforces the potential role of sinks in contributing to Enterobacterales infection and antimicrobial resistance in hospital patients, something that could be amenable to intervention. This article contains data hosted by Microreact.

scholarly journals Antimicrobial resistance prevalence in commensal Escherichia coli from broilers, fattening turkeys, fattening pigs and veal calves in European countries and association with antimicrobial usage at country level

2020 ◽  
Vol 69 (4) ◽  
pp. 537-547 ◽  
Author(s):  
Daniela Ceccarelli ◽  
Ayla Hesp ◽  
Jeanet van der Goot ◽  
Philip Joosten ◽  
Steven Sarrazin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Type Species ◽  
European Countries ◽  
Content Type ◽  
E Coli ◽  
Veal Calves ◽  
Link Type ◽  
Country Level ◽  
Fattening Pigs

The aim of this article is to report on antimicrobial resistance (AMR) in commensal Escherichia coli from livestock from several European countries. The relationships with antimicrobial usage (AMU) at country level and harmonized indicators to cover the most relevant AMR aspects for human health in animal production were also investigated. E. coli were isolated in faeces from broilers and fattening pigs (from nine countries), and fattening turkeys and veal calves (from three countries) and screened against a fixed antimicrobial panel. AMU data were collected at farm and average treatment incidences stratified by antimicrobial class, country and livestock species were calculated. Associations between AMR and AMU at country level were analysed. Independent of animal species, the highest resistance was observed for ampicillin, sulphamethoxazole, tetracycline and trimethoprim. E. coli from broilers showed the highest resistance level for (fluoro)quinolones, and multidrug resistance peaked in broilers and fattening turkeys. Colistin resistance was observed at very low levels with the exception of fattening turkeys. High resistance to third- and fourth-generation cephalosporins was detected in broilers and fattening turkeys. The lowest levels of resistance were for meropenem, azithromycin and tigecycline (<1 %). Significant correlations between resistance and usage at country level were detected in broilers for polymyxins and aminoglycosides, and in fattening pigs for cephalosporins, amphenicols, fluoroquinolones and polymyxins. None of the correlations observed between AMR and AMU were statistically significant for fattening turkey and veal calves. The strength of the analysis performed here is the correlation of aggregated data from the same farms at country level for both AMU and AMR within antimicrobial classes.

scholarly journals Characterization of Escherichia coli obtained from patients undergoing peritoneal dialysis and diagnosed with peritonitis in a Brazilian centre

2019 ◽  
Vol 68 (9) ◽  
pp. 1330-1340 ◽  
Author(s):  
Regiane C. B. Dias ◽  
Melissa A. Vieira ◽  
Ana C. Moro ◽  
Danilo F. M. Ribolli ◽  
Aydir C. M. Monteiro ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Peritoneal Dialysis ◽  
Antimicrobial Resistance ◽  
Virulence Factor ◽  
Type Species ◽  
Content Type ◽  
E Coli ◽  
Link Type ◽  
Biofilm Production ◽  
Encoding Genes

Purpose. This study aimed to characterize 27 Escherichia coli isolates obtained from peritoneal dialysis (PD)-related peritonitis that occurred at the University Hospital of Botucatu Medical School, Brazil, between 1997 and 2015. Methodology. These isolates were characterized regarding the occurrence of 22 virulence factor-encoding genes, antimicrobial resistance and biofilm production. We then evaluated whether these factors influenced the clinical outcome. Results. Over an 18-year period, 726 episodes of PD-related peritonitis were diagnosed, with 27 of them (3.7 %) being due to E. coli . The majority of the isolates were classified in phylogroups B1 (33.3 %), B2 (30.0 %) or F (18.0 %). fimH (100.0 %), ompT (66.7 %) and irp2 (51.9 %) were the most prevalent genes, while papA, papC, iha, sat, irp2, iucD, ireA, ibe10, ompT and kpsMTII were significantly more prevalent among isolates belonging to phylogroups B2 and F (P<0.05). Non-susceptibility to quinolones was detected in six isolates, which harboured chromosomal and/or plasmid-mediated quinolone resistance determinants, while two CTX-M extended-spectrum β-lactamase-producing E. coli were identified. Virulence factor-encoding genes (alone or in combination) and antimicrobial resistance were not associated with non-resolution outcomes. However, there was a trend for the ability to produce biofilm to be associated with treatment failure, although this association was not statistically significant. Conclusion. The E. coli isolates were heterogeneous in terms of the features investigated, and were susceptible to most of the antimicrobial drugs tested, despite the unsuccessful treatment observed in more than 50.0 % of the patients. Studies including more cases could help to clarify if biofilm production can influence the outcome in patients with PD-related peritonitis.

scholarly journals Antimicrobial resistance in Shiga toxin-producing Escherichia coli other than serotype O157 : H7 in England, 2014–2016

2020 ◽  
Vol 69 (3) ◽  
pp. 379-386 ◽  
Author(s):  
Amy Gentle ◽  
Martin R. Day ◽  
Katie L. Hopkins ◽  
Gauri Godbole ◽  
Claire Jenkins
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Shiga Toxin ◽  
Type Species ◽  
Gastrointestinal Disease ◽  
Foodborne Pathogen ◽  
Content Type ◽  
E Coli ◽  
Link Type

Introduction. Despite many ongoing surveillance projects and the recent focus on the veterinary and clinical ‘One Health’ aspects of antimicrobial resistance (AMR), evidence of the extent of any public health risk posed by animal reservoirs with respect to the transmission of resistant strains of Escherichia coli to humans remains varied and contentious. In the UK, the main zoonotic reservoir for the foodborne pathogen Shiga toxin-producing E. coli (STEC) is cattle and sheep. In this study, we adopt an alternative approach to the risk assessment of transmission of AMR E. coli from animals to humans, involving monitoring AMR in isolates of STEC, an established zoonotic, foodborne pathogen, from human cases of gastrointestinal disease. Aim. The aim of this study was to determine the genome-derived AMR profiles for STEC from human cases to assess the risk of transmission of multidrug-resistant STEC from ruminants to humans. Methodology. STEC belonging to 10 different clonal complexes (CCs) (n=457) isolated from human faecal specimens were sequenced and genome-derived AMR profiles were determined. Phenotypic susceptibility testing was undertaken on all isolates (n=100) predicted to be resistant to at least one class of antimicrobial. Results. Of the 457 isolates, 332 (72.7 %) lacked identifiable resistance genes and were predicted to be fully susceptible to 11 classes of antimicrobials; 125/332 (27.3 %) carried 1 or more resistance genes, of which 83/125 (66.4 %) were resistant to 3 or more classes of antibiotic. The percentage of isolates harbouring AMR determinants varied between CCs, from 4% in CC25 to 100% in CC504. Forty-six different AMR genes were detected, which conferred resistance to eight different antibiotic classes. Resistance to ampicillin, streptomycin, tetracyclines and sulphonamides was most commonly detected. Four isolates were identified as extended-spectrum β-lactamase producers. An overall concordance of 97.7 % (n=1075/1100) was demonstrated between the phenotypic and genotypic methods. Conclusion. This analysis provided an indirect assessment of the risk of transmission of AMR gastrointestinal pathogens from animals to humans, and revealed a subset of human isolates of the zoonotic pathogen STEC were resistant to the antimicrobials used in animal husbandry. However, this proportion has not increased over the last three decades, and thismay provide evidence that guidancepromoting responsible practice has been effective.

scholarly journals Genomic diversity of Escherichia coli isolates from backyard chickens and guinea fowl in the Gambia

2020 ◽  
Author(s):  
Ebenezer Foster-Nyarko ◽  
Nabil-Fareed Alikhan ◽  
Anuradha Ravi ◽  
Nicholas M. Thomson ◽  
Sheikh Jarju ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Type Species ◽  
Guinea Fowl ◽  
Genomic Diversity ◽  
Sub Saharan Africa ◽  
Content Type ◽  
E Coli ◽  
Link Type ◽  
Antimicrobial Resistance Gene ◽  
Sub Saharan

Chickens and guinea fowl are commonly reared in Gambian homes as affordable sources of protein. Using standard microbiological techniques, we obtained 68 caecal isolates of Escherichia coli from 10 chickens and 9 guinea fowl in rural Gambia. After Illumina whole-genome sequencing, 28 sequence types were detected in the isolates (4 of them novel), of which ST155 was the most common (22/68, 32 %). These strains span four of the eight main phylogroups of E. coli, with phylogroups B1 and A being most prevalent. Nearly a third of the isolates harboured at least one antimicrobial resistance gene, while most of the ST155 isolates (14/22, 64 %) encoded resistance to ≥3 classes of clinically relevant antibiotics, as well as putative virulence factors, suggesting pathogenic potential in humans. Furthermore, hierarchical clustering revealed that several Gambian poultry strains were closely related to isolates from humans. Although the ST155 lineage is common in poultry from Africa and South America, the Gambian ST155 isolates belong to a unique cgMLST cluster comprising closely related (38–39 alleles differences) isolates from poultry and livestock from sub-Saharan Africa – suggesting that strains can be exchanged between poultry and livestock in this setting. Continued surveillance of E. coli and other potential pathogens in rural backyard poultry from sub-Saharan Africa is warranted.

scholarly journals Antimicrobial resistance profiles of diarrhoeagenic Escherichia coli isolated from travellers returning to the UK, 2015–2017

2020 ◽  
Vol 69 (7) ◽  
pp. 932-943
Author(s):  
Megan D. Boxall ◽  
Martin R. Day ◽  
David R. Greig ◽  
Claire Jenkins
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Type Species ◽  
Antimicrobial Agents ◽  
Gastrointestinal Disease ◽  
Culture Methods ◽  
Content Type ◽  
Link Type ◽  
The Uk ◽  
Pcr Targeting

Introduction. Diarrhoeagenic Escherichia coli (DEC) are difficult to distinguish from non-pathogenic commensal E. coli using traditional culture methods. The implementation of PCR targeting specific virulence genes characteristic of the five DEC pathotypes, has improved the detection of DEC in faecal specimens from patients with symptoms of gastrointestinal disease. Aim. Antimicrobial resistance (AMR) profiles of 660 strains of DEC isolated between 2015 and 2017 from UK travellers reporting symptoms of gastrointestinal disease were reviewed to look for evidence of emerging AMR associated with travellers’ diarrhoea. Methodology. All isolates of DEC were sequenced, and sequence type, serotype, pathotype markers and AMR profiles were derived from the genome data. Results. A travel history was provided for 54.1 % (357/660) of cases, of which 77.0 % (275/357) reported travel outside the UK within 7 days of onset of symptoms, and 23.0 % (82/357) reported no travel in that time frame. Of the 660 strains of DEC in this study, 265 (40.2 %) samples were identified as EAEC, 48 (7.3 %) as EIEC, 61 (9.2 %) were ETEC and 286 (43.3 %) were EPEC. EPEC caused the highest percentage of infections in children (40.6 %) whilst the highest proportion of cases reporting recent travel were infected with ETEC (86.1 %). There were 390/660 (59.0 %) isolates resistant to at least one antimicrobial on the panel tested (EIEC, 81.3 %; ETEC, n=65.6 %; EAEC, n=73.2 %; EPEC, 40.9 %) and 265/660 (40.2 %) were multidrug-resistant (EIEC, 33.3 %; ETEC, 32.8 %; EAEC, 56.2 %; EPEC, 28.0 %). Genes conferring resistance to the beta-lactams and fluroquinolones were highest in the EAEC pathotype, 56.6 and 60.7%, respectively. Conclusions. Increasing MDR, along with resistance to the fluroquinolones and the third-generation cephalosporins, in DEC causing travellers’ diarrhoea provides further evidence for the need to restrict the use of antimicrobial agents and continuous monitoring.

scholarly journals Genomic diversity of Escherichia coli isolates from non-human primates in the Gambia

2020 ◽  
Vol 6 (9) ◽  
Author(s):  
Ebenezer Foster-Nyarko ◽  
Nabil-Fareed Alikhan ◽  
Anuradha Ravi ◽  
Gaëtan Thilliez ◽  
Nicholas M. Thomson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Host Species ◽  
Type Species ◽  
The Gambia ◽  
Genomic Diversity ◽  
Multi Drug Resistance ◽  
Erythrocebus Patas ◽  
Content Type ◽  
Link Type

Increasing contact between humans and non-human primates provides an opportunity for the transfer of potential pathogens or antimicrobial resistance between host species. We have investigated genomic diversity and antimicrobial resistance in Escherichia coli isolates from four species of non-human primates in the Gambia: Papio papio (n=22), Chlorocebus sabaeus (n=14), Piliocolobus badius (n=6) and Erythrocebus patas (n=1). We performed Illumina whole-genome sequencing on 101 isolates from 43 stools, followed by nanopore long-read sequencing on 11 isolates. We identified 43 sequence types (STs) by the Achtman scheme (ten of which are novel), spanning five of the eight known phylogroups of E. coli . The majority of simian isolates belong to phylogroup B2 – characterized by strains that cause human extraintestinal infections – and encode factors associated with extraintestinal disease. A subset of the B2 strains (ST73, ST681 and ST127) carry the pks genomic island, which encodes colibactin, a genotoxin associated with colorectal cancer. We found little antimicrobial resistance and only one example of multi-drug resistance among the simian isolates. Hierarchical clustering showed that simian isolates from ST442 and ST349 are closely related to isolates recovered from human clinical cases (differences in 50 and 7 alleles, respectively), suggesting recent exchange between the two host species. Conversely, simian isolates from ST73, ST681 and ST127 were distinct from human isolates, while five simian isolates belong to unique core-genome ST complexes – indicating novel diversity specific to the primate niche. Our results are of planetary health importance, considering the increasing contact between humans and wild non-human primates.

Antimicrobial resistance genes and genetic characteristics of multidrug-resistant Escherichia coli in a veterinary hospital in Taiwan

2021 ◽  
Vol 70 (11) ◽  
Author(s):  
Lii-Tzu Wu ◽  
Xin-Xia Wu ◽  
Se-Chin Ke ◽  
Yi-Pei Lin ◽  
Ying-Chen Wu ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
Type Species ◽  
Multidrug Resistant ◽  
Content Type ◽  
E Coli ◽  
Link Type ◽  
Antimicrobial Resistance Genes ◽  
Veterinary Hospital

Introduction. Antimicrobial resistance associated with animal hosts is easily transmitted to humans either by direct contact with resistant organisms or by transferring resistance genes into human pathogens. Gap statement. There are limited studies on antimicrobial resistance genes and genetic elements of multidrug-resistant (MDR) Escherichia coli in veterinary hospitals in Taiwan. Aim. The aim of this study was to investigate antimicrobial resistance genes in multidrug-resistant Escherichia coli from animals. Methodology. Between January 2014 and August 2015, 95 multidrug-resistant Escherichia coli isolates were obtained from pigs (n=66), avians (n=18), and other animals (n=11) in a veterinary hospital in Taiwan. Susceptibility testing to 24 antimicrobial agents of 14 antimicrobial classes was performed. Antimicrobial resistance genes, integrons, and insertion sequences were analysed by polymerase chain reaction and nucleotide sequencing. Pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing were used to explore the clonal relatedness of the study isolates. Results. Different antimicrobial resistance genes found in these isolates were associated with resistance to β-lactams, tetracycline, phenicols, sulfonamides, and aminoglycosides. Fifty-five of 95 E. coli isolates (55/95, 57.9 %) were not susceptible to extended-spectrum cephalosporins, and bla CTX-M-55 (11/55, 20.0 %) and bla CMY-2 (40/55, 72.7 %) were the most common extended-spectrum β-lactamase (ESBL) and AmpC genes, respectively. Both bla CTX-M and bla CMY-2 were present on conjugative plasmids that contained the insertion sequence ISEcp1 upstream of the bla genes. Plasmid-mediated FOX-3 β-lactamase-producing E. coli was first identified in Taiwan. Forty isolates (40/95, 42 %) with class 1 integrons showed seven resistance phenotypes. Genotyping of 95 E. coli isolates revealed 91 different XbaI pulsotypes and 52 different sequence types. PFGE analysis revealed no clonal outbreaks in our study isolates. Conclusion. This study showed a high diversity of antimicrobial resistance genes and genotypes among MDR E. coli isolated from diseased livestock in Taiwan. To our knowledge, this is the first report of plasmid-mediated ESBL in FOX-3 β-lactamase-producing E. coli isolates in Taiwan. MDR E. coli isolates from animal origins may contaminate the environment, resulting in public health concerns, indicating that MDR isolates from animals need to be continuously investigated.

PBP4 and PBP5 are involved in regulating exopolysaccharide synthesis during Escherichia coli biofilm formation

Microbiology ◽  
2021 ◽  
Vol 167 (3) ◽  
Author(s):  
Sathi Mallick ◽  
Shanti Kiran ◽  
Tapas Kumar Maiti ◽  
Anindya S. Ghosh
Keyword(s):  
Escherichia Coli ◽  
Biofilm Formation ◽  
Type Species ◽  
Pentose Phosphate ◽  
Bacterial Cells ◽  
Surface Adhesion ◽  
Content Type ◽  
Penicillin Binding Proteins ◽  
E Coli ◽  
Link Type

Escherichia coli low-molecular-mass (LMM) Penicillin-binding proteins (PBPs) help in hydrolysing the peptidoglycan fragments from their cell wall and recycling them back into the growing peptidoglycan matrix, in addition to their reported involvement in biofilm formation. Biofilms are external slime layers of extra-polymeric substances that sessile bacterial cells secrete to form a habitable niche for themselves. Here, we hypothesize the involvement of Escherichia coli LMM PBPs in regulating the nature of exopolysaccharides (EPS) prevailing in its extra-polymeric substances during biofilm formation. Therefore, this study includes the assessment of physiological characteristics of E. coli CS109 LMM PBP deletion mutants to address biofilm formation abilities, viability and surface adhesion. Finally, EPS from parent CS109 and its ΔPBP4 and ΔPBP5 mutants were purified and analysed for sugars present. Deletions of LMM PBP reduced biofilm formation, bacterial adhesion and their viability in biofilms. Deletions also diminished EPS production by ΔPBP4 and ΔPBP5 mutants, purification of which suggested an increased overall negative charge compared with their parent. Also, EPS analyses from both mutants revealed the appearance of an unusual sugar, xylose, that was absent in CS109. Accordingly, the reason for reduced biofilm formation in LMM PBP mutants may be speculated as the subsequent production of xylitol and a hindrance in the standard flow of the pentose phosphate pathway.

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