Notification of bacterial strains made available by the UK National Collection of Type Cultures in 2023

The National Collection of Type Cultures (NCTC) is a bacterial culture collection which is taxonomically and biologically diverse. NCTC holds approximately 6000 different strains from over 900 different species; among them strains originally isolated in the 19th century, strains for use as controls as stipulated EUCAST and ISO guidelines, type strains on which the description of bacterial species are based and other strains from a variety of backgrounds. The remit of NCTC is to provide authentic bacterial cultures of medical and veterinary interest to the scientific community, to support and enhance the reproducibility of scientific research and to improve global public health. To fulfil this remit, remain scientifically relevant and to preserve the legacy of contemporary medical bacteriology for future scientists, NCTC accessions strains of clinical significance: such as recently circulating and outbreak strains, diagnostic escape mutants and strains with novel antimicrobial resistance profiles. In 2018, 166 bacterial strains were accessioned into the NCTC and made available to the scientific community. These include NCTC 14052: a reference strain for emergent hyper-virulent K. pneumoniae, 4 type strains of newly described bacterial species, 82 strains accessioned from the Murray Collection of pre-antibiotic era Enterobacteriaceae and 8 strains with antimicrobial resistance mechanisms previously unrepresented in the collection, including NCTC 14208: a N. gonorrhoeae isolated from an instance of combined ceftriaxone and azithromycin treatment failure. Through literature review we have highlighted their value to the scientific community, both in their own right and in the context of bacterial strains already held by the NCTC.

The National Collection of Type Cultures (NCTC) is the world’s oldest repository of medically-relevant bacteria. NCTC contains 5,500 bacterial strains, 500 of which are anaerobes, with the collection regularly receiving new Type strains and recent clinical isolates. Fastidious anaerobes pose a unique challenge during the authentication process. NCTC must ensure that the strains are free from contamination and that the organism survives the lyophilisation process. Species-level identification of anaerobic bacterial strains is achieved using a combination of the both MALDI-TOF MS and VITEK2 instruments. This study evaluates the use of MALDI-TOF MS (Bruker) and VITEK2 (BioMerieux) to identify the anaerobic strains in the NCTC collection. 176 NCTC strains were tested on the MALDI-TOF platform and 60 strains were identified using VITEK2. MALDI-TOF was able to identify 79% anaerobes to genus-level and 64% to species-level. In comparison the VITEK2 identified 68% to genus and 46% to species-level. The main limiting factor for both these platforms is the database. This may be due to novel anaerobe species NCTC receives not being present on the databases. In the event of no identification, 16S ribosomal RNA sequencing is employed. Furthermore, detection of specific characteristics is carried out by specialist reference laboratories in Cardiff and Colindale, ensuring a robust collection of anaerobic bacteria for use in research and as control strains.

The National Collection of Type Cultures (NCTC) is the world’s oldest bacterial collection that was specifically established to provide strains globally to support scientific research. In addition to the general catalogue NCTC has a fully curated bacteriophage and plasmid archive that to date has not recently been made available to the wider scientific community. The NCTC bacteriophage collection consists of over 100 bacteriophage and their corresponding bacterial hosts which were originally deposited primarily for their value in bacterial typing. The collection consists of bacteriophage from the following hosts: Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli and Campylobacter. The NCTC Datta plasmid collection is a curated collection of over 500 unique plasmids which were originally curated to examine the biology of plasmid transfer between and within bacterial strains. The NCTC bacteriophage collection is currently being fully characterised using a range of modern methods including genomic sequencing and electron microscopy. The plasmid collection is also being characterised using genomic sequencing and restriction digest profiles. It is intended that once characterised and rebanked both the plasmid and bacteriophage collections will be made available in 2019 to scientists to support research and development. The NCTC bacteriophage and plasmid collections will both be dynamic, representing an active repositories into which microbiologists can deposit phages and plasmids to support accessibility and reproducibility in science.

Since its founding in January 1920, the National Collection of Type Cultures (NCTC) has played a fundamental role supporting microbiological research in Britain and globally. NCTC is an international repository for authenticated bacterial strains of medical and veterinary significance, making many available to researchers. Among the oldest collections of its kind still operating today, it presently holds almost 6,000 historically and microbiologically significant strains. Drawing on records of the Medical Research Council, which sponsored the NCTC, and uncataloged, previously unstudied archival holdings at the UK Health Security Agency, this article lays out and for the first time critically examines details of the establishment of the NCTC, and explores its far-reaching impacts on microbiology in the 20th century, and particularly on microbial taxonomy and classification.

In view of the encouraging results obtained from the preparation of carbon balance sheets for a number of species of Aspergilus , as reported in Part III, the work was extended to other groups and, by way of contrast, carbon balance sheets were prepared for a considerable number of species of Fusarium . It is evident from Wollenweber’s “ Monograph on the Fusaria '*(see ‘ Phytopathology ’ (1913), Vol. 3, p. 24) that the classification of the Fusaria on morphological grounds is very difficult. It was hoped that, as a result of the preparation of carbon balance sheets, some biochemical classification on the lines of the Aspergillus group might be possible, and in order to ensure that the cultures used were authentic, almost the whole of those chosen for investigation were Wollenweber’s own cultures purchased from the Centraalbureau voor Schimmelcultures at Baarn. The methods of investigation adopted were those described in Part II and applied to the Aspergillus group in Part III. The following is the history of the species of Fusarium used in this work :— *(1) F. viride (Lechm.) Wr., Catalogue No. Ag. 81. Purchased from Centraalbureau voor Schimmelcultures at Baarn. *(2) F. solani Mart. var. minus Wr., Catalogue No. Ag. 83. Purchased from Baarn. (3) F. lini Bolley, Catalogue No. Ag. 60. Purchased from British National Collection of Type Cultures, No. 1082. *(4) F. Martii App. et Wr., Catalogue No. Ag. 77. Purchased from Baarn. (5) F. species , Catalogue No. Ag. 80. Isolated at Ardeer from infected potato haulm. (6) F. dianthi Prill, et Del., Catalogue No. Ag. 69. Purchased from British National Collection of Type Cultures No. 1136. *(7) F. uncinatum Wr., Catalogue No. Ag. 75. Purchased from Baarn. ’•‘(8) F. trichothecioides Wr., Catalogue No. Ag. 73. Purchased from Baarn. *(9) F. tubercularioides (Corda) Sacc., Catalogue No. Ag. 72. Purchased from Baarn. *(10) F. coerulm (Lib.) Sacc., Catalogue No. Ag. 65. Purchased from Baarn. *(11) F. salicis Fuck., Catalogue No. Ag. 69. Purchased from Baarn. *(12) F.javanicum Koorders, Catalogue No. Ag. 78. Purchased from Baarn. *(13) F.falcatum App. et Wr., Catalogue No. Ag. 82. Purchased from Baarn. *(14) F. avenaceum (Fr.) Sacc., Catalogue No. Ag. 76. Purchased from Baarn. (15) F. sporotrichoides Sherb., Catalogue No. Ag. 58. Purchased from British National Collection of Type Cultures, No. 1296. *(16) F. sambucinum Fuck., Catalogue No. Ag. 70. Purchased from Baarn. (17) F. vasinfectum Atk., Catalogue No. Ag. 71. Purchased from Baarn. *(18) F. rhizophilum Corda, Catalogue No. Ag. 74. Purchased from Baarn. *(19) F. metachroum Ap p . et W r ., Catalogue No. Ag. 68. Purchased from Baarn. (20) F. species , Catalogue No. Ag. 61. Isolated at Ardeer from a rotting potato. *(21) F. orthoceras App . et W r ., Catalogue No. Ag. 66. Purchased from Baarn. (22) F. scirpi P amr et Fautr., Catalogue No. Ag. 79. Purchased from Baarn. (23) F. oxysporum Schlecht, Catalogue No. Ag. 67. Purchased from Baarn. Fifteen of the cultures in the above list which are marked with an asterisk were Wollenweber’s cultures purchased from Baarn. The carbon balance sheets prepared for these species are given in Tables I and II.

The National Collection of Type Cultures (NCTC) was founded on 1 January 1920 in order to fulfil a recognized need for a centralized repository for bacterial and fungal strains within the UK. It is among the longest-established collections of its kind anywhere in the world and today holds approximately 6000 type and reference bacterial strains – many of medical, scientific and veterinary importance – available to academic, health, food and veterinary institutions worldwide. Recently, a collaboration between NCTC, Pacific Biosciences and the Wellcome Sanger Institute established the NCTC3000 project to long-read sequence and assemble the genomes of up to 3000 NCTC strains. Here, at the beginning of the collection’s second century, we introduce the resulting NCTC3000 sequence read datasets, genome assemblies and annotations as a unique, historically and scientifically relevant resource for the benefit of the international bacterial research community.

100 years and counting: the National Collection of Type Cultures centenary

Campylobacteriosis incited by C. jejuni is a significant enteric disease of human beings. A person working with two reference strains of C. jejuni National Collection of Type Cultures (NCTC) 11168 developed symptoms of severe enteritis including bloody diarrhea. The worker was determined to be infected by C. jejuni. In excess of 50 isolates were recovered from the worker’s stool. All of the recovered isolates and the two reference strains were indistinguishable from each other based on comparative genomic fingerprint subtyping. Whole genome sequence analysis indicated that the worker was infected with a C. jejuni NCTC 11168 obtained from the American Type Culture Collection; this strain (NCTC 11168-GSv) is the genome sequence reference. After passage through the human host, major genetic changes including indel mutations within twelve contingency loci conferring phase variations were detected in the genome of C. jejuni. Specific and robust single nucleotide polymorphism (SNP) changes in the human host were also observed in two loci (Cj0144c, Cj1564). In mice inoculated with an isolate of C. jejuni NCTC 11168-GSv from the infected person, the isolate underwent further genetic variation. At nine loci, mutations specific to inoculated mice including five SNP changes were observed. The two predominant SNPs observed in the human host reverted in mice. Genetic variations occurring in the genome of C. jejuni in mice corresponded to increased densities of C. jejuni cells associated with cecal mucosa. In conclusion, C. jejuni NCTC 11168-GSv was found to be highly virulent in a human being inciting severe enteritis. Host-specific mutations in the person with enteritis occurred/were selected for in the genome of C. jejuni, and many were not maintained in mice. Information obtained in the current study provides new information on host-specific genetic adaptation by C. jejuni.

ABSTRACTHere, we report on the 47 bacterial strains made available by the National Collection of Type Cultures in 2021, alongside a commentary on these strains and their significance.

Here, we report on the one hundred and twenty-five bacterial strains made available by the National Collection of Type Cultures in 2022 alongside a commentary on the strains, their provenance and significance.

This annotation contains a series of amendments and additions to the National Collection of Type Culture data on strains held in the National Collection of Type Cultures which are given in “A list of type and reference strains of bacteria,” (Sneath and Skerman 1966). Amendments or additions to the data of other Culture Collections are not included. It is suggested that copies of the list should be emended to avoid errors until a revised list is published.

On the basis of long-term experience with the preservation of the pathogenic bacteria of the Czechoslovak National Collection of Type Cultures, it is concluded that the suspending medium is a factor of primary importance in the preservation of these organisms in the freeze-dried state. The primary index of suspending medium effectiveness is the level of protection it affords against the adverse effects of low (subzero) temperatures, dehydration, long-term storage, and rehydration. A number of simple and compound suspending media were studied for their protective effects on cultures from over 50 genera of predominantly pathogenic bacteria. The results indicate that not only each bacterial genus and species but also frequently every strain of a given serological type must be looked upon as a distinct biological entity, the preservation of the viability, activity, and desirable characters of which must be tested in different protective media in preliminary experiments. Heat testing (at 75 to 100 C) of freeze-dried cultures kept under high vacuum is recommended as a good indicator of adequate protection provided by a suspending medium. With the freeze-drying technique used, the best results for the largest number of species were obtained with a mixture of calf serum or defibrinated sheep blood and lactose solution (to a final concentration of 5 to 10%) and Annear’s peptone-containing medium. Individual suspending media were evaluated in relation to individual strains, and recommendations are made as to the preferred medium on the basis of control tests performed at 5-, 10-, and 15-year intervals.

To identify and make available through the National Collection of Type Cultures (NCTC) a set of reference isolates for the clonal complexes of Campylobacter jejuni. The development of a multilocus sequence typing scheme for C. jejuni enabled the genetic characterization of a large number of isolates (n = 814) from cases of human disease, animals, birds and their food products. The nucleotide sequence data were used to assign each isolate an allelic profile or sequence type (ST) and examine the C. jejuni population structure in terms of clonal complexes. The clonal complexes consisted of an abundant central or founder genotype (ST), after which the complex was named, together with very closely related, generally less abundant genotypes differing from the founder at one, two or three loci. The clonal complex is an informative unit for the study C. jejuni epidemiology. It provides data which enabled the choice of 13 C. jejuni founder isolates for submission to the NCTC as a representative cross-section of the C. jejuni population. These 13 isolates provide a defined resource for further research into aspects of C. jejuni biology such as genomic diversity, virulence and adaptation to particular hosts or environmental survival. This isolate collection is available through the NCTC and provides a resource for further research.

Raoultella terrigena is a bacterial species associated with soil and aquatic environments; however, sporadic cases of opportunistic disease in humans have been reported. Here, we report the first two complete genome sequences from clinical strains isolated from human sources that have been deposited in the National Collection of Type Cultures (NCTC).

Fluorescent amplified fragment length polymorphism (FAFLP) analysis was applied to genetically fingerprint 'working culture control strains' used by accredited food microbiology laboratories. A working culture control strain is defined as a subculture from a strain initially obtained from an authenticated source [such as the National Collection of Type Cultures (NCTC)] that is maintained for use with routine testing within the laboratory. Working culture control strains from eight food examination laboratories, representing four bacterial species, were analysed by FAFLP; these were Salmonella Nottingham, Staphylococcus aureus, Listeria monocytogenes and Bacillus cereus. The resultant FAFLP profiles of the eight working culture control strains for each of these species were compared against the appropriate freeze-dried ampoules obtained directly from NCTC. FAFLP results demonstrated that within 50% of working cultures analysed, several laboratories were routinely using working cultures that were genetically different from the original reference NCTC strains. This study highlights the need for laboratories to review the protocols used to process and maintain control strains and working cultures, with a potential view to utilize single-use quality control materials.