Luca Bano
@izsvenezie.it
Microviology and Diagnostic Veterinary Laboratory
Istituto Zooprofilattico Sperimentale delle Venezie
EDUCATION
PhD in Animal Pathology and Veterinary Hygiene, University of Milan
Doctor in Veterinary Medicine, University of Bologna
RESEARCH INTERESTS
Clostridia, botulism, antimicrobial resistances, animal pathology, bacterial characterization, avian pathology, rabbit pathology, bovine pathology, bacteric agents of bioterrorism
Scopus Publications
Scopus Publications
Andrea Balboni, Giovanni Franzo, Luca Bano, Lorenza Urbani, Sofia Segatore, Alessia Rizzardi, Benedetta Cordioli, Matteo Cornaggia, Alessia Terrusi, Kateryna Vasylyeva,et al.
Elsevier BV
Luigia Pinna, Annamaria Coccollone, Marcella Maxia, Luca Bano, Concetta Scalfaro, Daniela Mandas, and Manuele Liciardi
MDPI AG
Clostridium botulinum is the main causative agent of botulism in humans and animals. The ingestion of the botulinum neurotoxin, usually types C and D, has been shown to produce disease (neurological symptoms) in most botulism cases in cattle. We report an outbreak in Southern Sardinia that involved a livestock farm with 120 animals, 39 of which died. The aim of this report is to describe the course of this outbreak and the progression of symptoms up to the death of some animals; we also describe the therapeutic approach applied in this case and the analytical techniques used to diagnose the disease. Finally, we emphasize the importance of promptly proceeding with the sampling of several matrixes when a suspicion of botulism arises.
Andrea Laconi, Roberta Tolosi, Ilenia Drigo, Luca Bano, and Alessandra Piccirillo
Elsevier BV
Barbara Salerno, Matteo Cornaggia, Raffaella Sabatino, Andrea Di Cesare, Maddalena Furlan, Lisa Barco, Massimiliano Orsini, Benedetta Cordioli, Claudio Mantovani, Luca Bano,et al.
Frontiers Media SA
A side effect of antibiotic usage is the emergence and dissemination of antibiotic resistance genes (ARGs) within microbial communities. The spread of ARGs among pathogens has emerged as a public health concern. While the distribution of ARGs is documented on a global level, their routes of transmission have not been clarified yet; for example, it is not clear whether and to what extent the emergence of ARGs originates in farms, following the selective pressure exerted by antibiotic usage in animal husbandry, and if they can spread into the environment. Here we address this cutting edge issue by combining data regarding antimicrobial usage and quantitative data from selected ARGs (blaTEM, blaCTXM, ermB, vanA, qnrS, tetA, sul2, and mcr-1) encoding for resistance to penicillins, macrolides-lincosamides-streptogramins, glycopeptides, quinolones, tetracyclines, sulfonamides, and colistin at the farm level. Results suggest that dairy farms could be considered a hotspot of ARGs, comprising those classified as the highest risk for human health and that a correlation existed between the usage of penicillins and blaTEM abundances, meaning that, although the antibiotic administration is not exclusive, it remains a certain cause of the ARGs' selection and spread in farms. Furthermore, this study identified the role of calves as the main source of ARGs spread in dairy farms, claiming the need for targeted actions in this productive category to decrease the load of ARGs along the production chain.
Arianna Peruzzo, Carmen Losasso, Adriana Di Castri, Ilenia Drigo, Luca Bano, and Massimiliano Orsini
American Society for Microbiology
We report the whole-genome sequence of a Campylobacter strain that was isolated from breeding pheasants presenting “bulgy eyes” in Italy. Traditional molecular typing methods did not return any reliable result. Whole-genome sequencing and sequence comparison with known genomes did not meet the criteria for assignment to an existing species.
Ginevra Brocca, Samuele Zamparo, Tobia Pretto, Alessandro Calore, Andrea Marsella, Romy Lucon Xiccato, Matteo Cornaggia, Luana Cortinovis, Luca Bano, Anna Toffan,et al.
Wiley
Silvia Fillo, Francesco Giordani, Elena Tonon, Ilenia Drigo, Anna Anselmo, Antonella Fortunato, Florigio Lista, and Luca Bano
MDPI AG
In animals, botulism is commonly sustained by botulinum neurotoxin C, D or their mosaic variants, which are produced by anaerobic bacteria included in Clostridium botulinum group III. In this study, a WGS has been applied to a large collection of C. botulinum group III field strains in order to expand the knowledge on these BoNT-producing Clostridia and to evaluate the potentiality of this method for epidemiological investigations. Sixty field strains were submitted to WGS, and the results were analyzed with respect to epidemiological information and compared to published sequences. The strains were isolated from biological or environmental samples collected in animal botulism outbreaks which occurred in Italy from 2007 to 2016. The new sequenced strains belonged to subspecific groups, some of which were already defined, while others were newly characterized, peculiar to Italian strains and contained genomic features not yet observed. This included, in particular, two new flicC types (VI and VII) and new plasmids which widen the known plasmidome of the species. The extensive genome exploration shown in this study improves the C. botulinum and related species classification scheme, enriching it with new strains of rare genotypes and permitting the highest grade of discrimination among strains for forensic and epidemiological applications.
Andrea Laconi, Ilenia Drigo, Nicola Palmieri, Lisa Carraro, Elena Tonon, Raffaela Franch, Luca Bano, and Alessandra Piccirillo
Elsevier BV
Campylobacter jejuni and Campylobacter coli have commonly been considered harmless commensal inhabitants of the chicken gut; however, these Campylobacter spp. are known to be able to multiply in the gut and invade other tissues, negatively affecting host health and performance. In this study, fourteen Campylobacter spp. were isolated from chickens showing foci of necrosis on the liver surface resembling lesions observed in cases of avian vibrionic hepatitis/spotty liver disease. The whole genome sequences of the fourteen isolates were analysed and their virulomes compared to those of Campylobacter reference sequences, aiming to investigate the possible association between virulence genes and the observed pathological lesions. Nine C. jejuni and five C. coli were studied. These Campylobacter shared twelve virulence factors with other isolates originated from chicken livers and hosted a higher number of virulence-associated genes in comparison to the reference genomes, including genes encoding for factors involved in adherence to and invasion of the intestinal epithelial cells. Our findings seem to point out that these twelve common virulence-associated genes, together with the presence of a high number of virulence factors involved in adherence, invasion and motility, might be responsible for the extra-intestinal spread of our isolates and the colonization of parenchymatous tissues, possibly causing the pathological lesions observed.
Cedric Woudstra, Tommi Mäklin, Yagmur Derman, Luca Bano, Hanna Skarin, Christelle Mazuet, Antti Honkela, and Miia Lindström
American Society for Microbiology
Clostridium botulinum group III is the anaerobic Gram-positive bacteria producing the deadly neurotoxin responsible for animal botulism. Here, we used long-read sequencing to produce four complete genomes from Clostridium botulinum group III neurotoxin types C, D, C/D, and D/C. The protocol to obtain high-molecular-weight DNA from C. botulinum group III is described.
Nicola Pozzato, Laura D’Este, Laura Gagliazzo, Marta Vascellari, Monia Cocchi, Fabrizio Agnoletti, Luca Bano, Antonio Barberio, Debora Dellamaria, Federica Gobbo,et al.
SAGE Publications
Laboratory tests provide essential support to the veterinary practitioner, and their use has grown exponentially. This growth is the result of several factors, such as the eradication of historical diseases, the occurrence of multifactorial diseases, and the obligation to control endemic and epidemic diseases. However, the introduction of novel techniques is counterbalanced by economic constraints, and the establishment of evidence- and consensus-based guidelines is essential to support the pathologist. Therefore, we developed standardized protocols, categorized by species, type of production, age, and syndrome at the Istituto Zooprofilattico Sperimentale delle Venezie (IZSVe), a multicenter institution for animal health and food safety. We have 72 protocols in use for livestock, poultry, and pets, categorized as, for example, “bovine enteric calf”, “rabbit respiratory”, “broiler articular”. Each protocol consists of a panel of tests, divided into ‘mandatory’ and ‘ancillary’, to be selected by the pathologist in order to reach the final diagnosis. After autopsy, the case is categorized into a specific syndrome, subsequently referred to as a syndrome-specific panel of analyses. The activity of the laboratories is monitored through a web-based dynamic reporting system developed using a business intelligence product (QlikView) connected to the laboratory information management system (IZILAB). On a daily basis, reports become available at general, laboratory, and case levels, and are updated as needed. The reporting system highlights epidemiologic variations in the field and allows verification of compliance with the protocols within the organization. The diagnostic protocols are revised annually to increase system efficiency and to address stakeholder requests.
Francesca Blasi, Carmela Lovito, Elisa Albini, Luca Bano, Gastone Dalmonte, Ilenia Drigo, Carmen Maresca, Francesca Romana Massacci, Serenella Orsini, Sara Primavilla,et al.
MDPI AG
The emergence of Clostridioides difficile as the main agent of antibiotic-associated diarrhoea has raised concerns about its potential zoonotic role in different animal species. The use of antimicrobials is a major risk factor for C. difficile infection. Here, we provide data on C. difficile infection in dairy and beef calves in Umbria, a region in central Italy. This cross-sectional study focuses on prevalence, risk factors, ribotypes, toxinotypes and antimicrobial resistance profiles of circulating ribotypes. A prevalence of 19.8% (CI95%, 12–27.6%) positive farms was estimated, and the prescription of penicillins on the farms was associated with C. difficile detection (OR = 5.58). Eleven different ribotypes were found, including the ST11 sublineages RT-126 and -078, which are also commonly reported in humans. Thirteen isolates out of 17 showed resistance to at least one of clindamycin, moxifloxacin, linezolid and vancomycin. Among them, multiple-drug resistance was observed in two isolates, belonging to RT-126. Furthermore, RT-126 isolates were positive for tetracycline resistance determinants, confirming that tetracycline resistance is widespread among ST11 isolates from cattle. The administration of penicillins increased the risk of C. difficile in calves: this, together with the recovery of multi-resistant strains, strongly suggests the need for minimising antibiotic misuse on cattle farms.
Ilenia Drigo, Elena Tonon, Simone Pascoletti, Fabrizio Anniballi, Suzanne R. Kalb, and Luca Bano
MDPI AG
Botulinum neurotoxins (BoNTs) are among the most poisonous known biological substances, and therefore the availability of reliable, easy-to use tools for BoNT detection are important goals for food safety and human and animal health. The reference method for toxin detection and identification is the mouse bioassay (MBA). An EndoPep-MS method for BoNT differentiation has been developed based on mass spectrometry. We have validated and implemented the EndoPep-MS method on a Bruker MALDI Biotyper for the detection of BoNT/C and D serotypes. The method was extensively validated using experimentally and naturally contaminated samples comparing the results with those obtained with the MBA. Overall, the limit of detection (LoD) for both C and D toxins were less than or equal to two mouse lethal dose 50 (mLD50) per 500 µL for all tested matrices with the exception of feces spiked with BoNT/C which showed signals not-related to specific peptide fragments. Diagnostic sensitivity, specificity and positive predictive value were 100% (95% CI: 87.66–100%), 96.08% (95% CI: 86.54–99.52%), and 93.33% (95% CI: 78.25–98.20%), respectively, and accuracy was 97.47% (95% CI: 91.15–99.69%). In conclusion, the tests carried out showed that the EndoPep-MS method, initially developed using more powerful mass spectrometers, can be applied to the Bruker MALDI Biotyper instrument with excellent results including for detection of the proteolytic activity of BoNT/C, BoNT/D, BoNT/CD, and BoNT/DC toxins.
G. Pozza, A. Pinto, S. Crovato, G. Mascarello, L. Bano, M. Dacasto, A. Battisti, B. Bartoli, L. Ravarotto, and S. Marangon
Informa UK Limited
Abstract The scientific community considers the improper use of antimicrobials in farm animals among the causes of the insurgent bacterial resistance contributing to the wider pool of resistance at the animal/human interface with serious public health implications. The present study aims to describe the current perceptions regarding antimicrobial use (AMU) and resistance (AMR) and the prescribing behaviour of two different target groups: cattle and pig veterinary practitioners working in Italy. A semi-structured questionnaire was designed and administered using the Computer-Assisted Web Interviewing method. Among the 789 participants who completed the questionnaire, 53.5% and 12.2% were cattle and pig veterinarians, respectively. Differences between the two groups emerged in their opinions concerning different topics. For example, 69.4% and 85.8% of cattle veterinarians claimed to ‘somewhat or strongly agree’ with the statements ‘prescribing broad-spectrum antibiotics in rearing farms increases AMR’ and ‘the preventive use of antibiotics fosters the development of AMR’, against the observed 59.4% and 69.8% of pig veterinarians (p = .050 and p = .000, respectively). Moreover, 26% of pig veterinarians claimed to ‘somewhat or strongly agree’ with the statement ‘alternative methods currently available could be an efficient alternative to antimicrobial treatment’, against 16.1% of cattle veterinarians (p = .022). At the same time, no differences between the two groups emerged regarding the danger inadequate AMU in animals poses on both animal and human health. From collected data, the need to provide appropriate training strategies with the aim of adopting a behaviour more consistent with the guidelines for prudent AMU in cattle and pig production systems has emerged. HIGHLIGHTS 85.8% of cattle vs. 69.8% of pig veterinarians agreed with the statement ‘the preventive use of antibiotics fosters the development of AMR’. 64.5% of cattle and 69.1% of pig veterinarians declared they suggest/prescribe alternative approaches to the use of antimicrobials. ‘Hygiene-biosecurity-management’ and ‘nutritive principles’ are the alternative strategies most suggested by cattle and pig veterinarians, respectively.
Andrea Balboni, Giovanni Franzo, Luca Bano, Stefano De Arcangeli, Alessia Rizzardi, Lorenza Urbani, Sofia Segatore, Federica Serafini, Francesco Dondi, and Mara Battilani
Frontiers Media SA
A growing number of studies suggest that the lower urinary tract of humans and dogs can harbor a urinary microbiota. Nevertheless, a certain concern has developed that the microbiota reported could be due to unaccounted contamination, especially in low-biomass samples. The aim of this study was to investigate the bacterial community which populates the urine of healthy cats using two approaches: a culture-dependent approach which consisted of the expanded quantitative urine culture (EQUC) techniques capable of identifying live bacteria not growing in standard urine cultures, and a culture-independent approach which consisted of 16S ribosomal RNA next generation sequencing (16S rRNA NGS) capable of identifying bacterial DNA and exploring microbial diversity with high resolution. To avoid confounding factors of possible bacterial contamination, the urine was sampled using ultrasound-guided cystocentesis, and several sample controls and negative controls were analyzed. The urine sampled from the 10 cats included in the study showed no bacterial growth in the EQUC procedure. Although several reads were successfully originated using 16S rRNA NGS, a comparable pattern was observed between urine samples and the negative control, and no taxa were statistically accepted as non-contaminant. Taken together, the results obtained allowed stating that no viable bacteria were present in the urine of healthy cats without lower urinary tract disease and urinary tract infections, and that the bacterial DNA detected was of contaminant origin.
Luca Bano, Matthias Kiel, Gabriele Sales, Andrew C. Doxey, Michael J. Mansfield, Haleluya T. Wami, Marco Schiavone, Ornella Rossetto, Marco Pirazzini, Ulrich Dobrindt,et al.
American Society for Microbiology
Eubacterium tarantellae was originally cultivated from the brain of fish affected by twirling movements. Here, we present the draft genome sequence of E. tarantellae DSM 3997, which consists of 3,982,316 bp. Most protein-coding genes in this strain are similar to genes of Clostridium bacteria, supporting the renaming of E. tarantellae as Clostridium tarantellae .
Elena Circella, Antonio Camarda, Luca Bano, Giacomo Marzano, Roberto Lombardi, Francesco D’Onghia, and Grazia Greco
MDPI AG
Any human activity, even if aimed at the improvement of a natural area, can potentially affect wildlife, leading to possible short-term or long-term changes due to the human–wildlife interaction. In this study, a botulism outbreak which occurred in waterfowl in a nature reserve after a conservative environmental action is reported. More than 180 different species of wild birds, including seventy waterfowl species, live in the area. The wildlife reserve rangers built an artificial pond equipped with draining canals in the wetland in order to improve the environment of waterfowl species and to facilitate their supply of food. Then, presumably due to tidal rides, gray mullets (Mugil cephalus) arrived from the sea and settled in the pond. The number of fishes gradually increased, and several fishes died with a peak of mortality in the summer of 2017, creating a great amount of decaying organic material and the optimal conditions for Clostridium botulinum growth and toxin production. A botulism outbreak then occurred rapidly and was characterised by flaccid paralysis and sudden mortality of the birds. Seven mallard ducks (Anas platyrhynchos), 4 common teals (Anas crecca), 1 garganey (Anas querquedula), 2 wood sandpipers (Tringa glareola), 1 little egret (Egretta garzetta), 1 little grebe (Tachybaptus ruficollis), and 4 Eurasian coots (Fulica atra) were found dead. Interestingly, the toxin identified as responsible for the disease outbreak was the mosaic of type C and D toxins (C/D type). The prompt removal of the fish carcasses led to a rapid resolution of the outbreak of the disease, highlighting the relevance of a correct management for any action in environmental contexts. The conclusion is that any human activity in wildlife habitats should be carefully considered in order to assess the possible impacts and to quickly identify the possible risks of changes in wildlife population.
Gianpiero Zamperin, Adelaide Milani, Alice Fusaro, Alessia Schivo, Luca Zandonà, Luca Bano, and Isabella Monne
American Society for Microbiology
Rabbit endogenous lentivirus type K (RELIK) was discovered in the genome of the European rabbit ( Oryctolagus cuniculus ). In our study, we present three complete genome sequences of RELIK viruses generated using a target amplification approach performed on the RNA of commercial rabbits from Italy.
Cédric Woudstra, Caroline Le Maréchal, Rozenn Souillard, Fabrizio Anniballi, Bruna Auricchio, Luca Bano, Marie-Hélène Bayon-Auboyer, Miriam Koene, Isabelle Mermoud, Roseane B. Brito,et al.
Elsevier BV
Adelaide Milani, Gianpiero Zamperin, Alice Fusaro, Annalisa Salviato, Luca Bano, Luca Zandonà, Romina Brunetta, and Isabella Monne
American Society for Microbiology
Using a metagenomics approach, we were able to determine for the first time the full-genome sequence of a psittacine adenovirus 1 isolate that was recovered from the liver of a dead Senegal parrot ( Poicephalus senegalus ) in Italy. The results of the phylogenetic investigations revealed the existence of high genetic diversity among adenoviruses circulating in psittacine birds.
Luca Bano, Elena Tonon, Ilenia Drigo, Marco Pirazzini, Angela Guolo, Giovanni Farina, Fabrizio Agnoletti, and Cesare Montecucco
MDPI AG
The presence of botulinum neurotoxin-producing Clostridia (BPC) in food sources is a public health concern. In favorable environmental conditions, BPC can produce botulinum neurotoxins (BoNTs) outside or inside the vertebrate host, leading to intoxications or toxico-infectious forms of botulism, respectively. BPC in food are almost invariably detected either by PCR protocols targeted at the known neurotoxin-encoding genes, or by the mouse test to assay for the presence of BoNTs in the supernatants of enrichment broths inoculated with the tested food sample. The sample is considered positive for BPC when the supernatant contains toxic substances that are lethal to mice, heat-labile and neutralized in vivo by appropriate polyclonal antibodies raised against purified BoNTs of different serotypes. Here, we report the detection in a food sample of a Clostridium tetani strain that produces tetanus neurotoxins (TeNTs) with the above-mentioned characteristics: lethal for mice, heat-labile and neutralized by botulinum antitoxin type B. Notably, neutralization occurred with two different commercially available type B antitoxins, but not with type A, C, D, E and F antitoxins. Although TeNT and BoNT fold very similarly, evidence that antitoxin B antiserum can neutralize the neurotoxic effect of TeNT in vivo has not been documented before. The presence of C. tetani strains in food can produce misleading results in BPC detection using the mouse test.
Fabrizio Agnoletti, Romina Brunetta, Luca Bano, Ilenia Drigo, and Elena Mazzolini
Elsevier BV
Reliable indicators of antimicrobial consumption (AMC) measured with harmonised data and supported by indicators for antimicrobial resistance (AMR) at herd level are necessary to target antimicrobial misuse in food-producing animals. AMC data in 2010-2015 in 32 Italian industrial rabbit holdings weighted with semester production and standardised with animal daily doses (ADDs) were collected. Herd-level AMR against eight antimicrobials was assessed in Escherichia coli, Enterococcus faecalis and Enterococcus hirae collected in 2014-2015. Escherichia coli were assessed for mcr-1 and mcr-2 genes. To produce 1 kg of live rabbit, a mean of 71.8 ADDs was used. Overall AMC reduced over time (P < 0.05) owing to lowering consumption of tetracyclines (P < 0.05) and colistin (P < 0.01), but consumption of quinolones (P < 0.05), bacitracin (P < 0.01) and sulfonamides (P = 0.017) increased. All except one indicator E. coli were wild-type for cefotaxime, whereas 97% displayed reduced susceptibility to tetracyclines, 89% to trimethoprim, 63% to enrofloxacin, 24% to chloramphenicol and 21% to colistin. mcr-1 was detected in 50/320 E. coli isolates from 15/32 holdings; mcr-2 was not detected in 58 isolates with colistin MIC ≥ 2 mg/L. All 305 enterococci were wild-type for ampicillin, ciprofloxacin and vancomycin and displayed reduced tetracycline susceptibility. The mean antimicrobial resistance index (ARI) was 0.5 for E. coli and 0.3 for enterococci. ARI was significantly correlated with AMC at herd level for enterococci (P = 0.008) but not E. coli where high ARI levels were found in a few holdings with low AMC.
Cédric Woudstra, Caroline Le Maréchal, Rozenn Souillard, Fabrizio Anniballi, Bruna Auricchio, Luca Bano, Marie-Hélène Bayon-Auboyer, Miriam Koene, Isabelle Mermoud, Roseane B. Brito,et al.
Elsevier BV
Clostridium botulinum group III is mainly responsible for botulism in animals. It could lead to high animal mortality rates and, therefore, represents a major environmental and economic concern. Strains of this group harbor the botulinum toxin locus on an unstable bacteriophage. Since the release of the first complete C. botulinum group III genome sequence (strain BKT015925), strains have been found to contain others mobile elements encoding for toxin components. In this study, seven assays targeting toxin genes present on the genetic mobile elements of C. botulinum group III were developed with the objective to better characterize C. botulinum group III strains. The investigation of 110 C. botulinum group III strains and 519 naturally contaminated samples collected during botulism outbreaks in Europe showed alpha-toxin and C2-I/C2-II markers to be systematically associated with type C/D bont-positive samples, which may indicate an important role of these elements in the pathogenicity mechanisms. On the contrary, bont type D/C strains and the related positive samples appeared to contain almost none of the markers tested. Interestingly, 31 bont-negative samples collected on farms after a botulism outbreak revealed to be positive for some of the genetic mobile elements tested. This suggests loss of the bont phage, either in farm environment after the outbreak or during laboratory handling.
Francesca Romana Massacci, Chiara Francesca Magistrali, Lucilla Cucco, Ludovica Curcio, Luca Bano, PierMario Mangili, Eleonora Scoccia, Magne Bisgaard, Bent Aalbæk, and Henrik Christensen
Elsevier BV
In rabbit, P. multocida is considered a predominant pathogenic agent; despite this, few data on the molecular epidemiology are available so far. The aim of this work was to characterize P. multocida isolates from rabbit affected by various diseases in Italy. Comparison was made to reference strains from other countries. Thirty-nine isolates were tested using PCRs to detect the genes coding capsular antigens, virulence factors and lipopolysaccharide structures (LPS). Multilocus sequence typing (MLST) was performed and 19 STs registered that belonged to 9 clonal complexes. Italian isolates were all related to P. multocida subsp. P. multocida. Three sequence types dominated (ST9, ST50 and ST74). The isolates were assigned to capsular types A (20/39), D (9/39) and F (10/39), to virulence genes pfhA (13/39), hgbB (21/39) and pfhA+hgbB (4/39) (one without virulence factors) and the isolates either belonged to the LPS genotypes 3 (22/39) or 6 (17/39). The clonal relationships of the Italian strains from rabbit had similarity to previously reported rabbit isolates that belonged to ST9, ST74, ST204 and ST206, however, they differed from other rabbit references strains that belonged to six other STs. In particular, ST9 with capsular type F has been previously reported from diseased rabbit in Czech Republic and ST74 has been observed for older rabbit isolates. ST50 has probably been reported from Spain. ST9 and ST50 have previously also been reported from birds and pig, respectively, whereas ST74 has exclusively been reported from pig. It remains to be investigated if the isolates obtained from diseased rabbit in Italy represent introductions from other host or they are primarily of rabbit origin.
Luca Bano, Ilenia Drigo, Elena Tonon, Simone Pascoletti, Cinzia Puiatti, Fabrizio Anniballi, Bruna Auricchio, Florigio Lista, Cesare Montecucco, and Fabrizio Agnoletti
Elsevier BV
Animal botulism is primarily due to botulinum neurotoxin (BoNT) types C, D or their chimeric variants C/D or D/C, produced by Clostridium botulinum group III, which appears to include the genetically indistinguishable Clostridium haemolyticum and Clostridium novyi. In the present study, we used matrix-assisted laser desorption-ionization time-of-flight mass spectrometry (MALDI TOF MS) to identify and characterize 81 BoNT-producing Clostridia isolated in 47 episodes of animal botulism. The instrument's default database, containing no entries for Clostridium botulinum, permitted reliable identification of 26 strains at the genus level. Although supplementation of the database with reference strains enhanced the instrument's ability to identify the neurotoxic strains at the genus level, resolution was not sufficient to recognize field strains at species level. Characterization by MALDI TOF confirmed the well-documented phenotypic and genetic differences between Clostridium botulinum strains of serotypes normally implicated in human botulism (A, B, E, F) and other Clostridium species able to produce BoNTs type C and D. The chimeric and non-chimeric field strains grouped separately. In particular, very low similarity was found between two non-chimeric type C field strains isolated in the same outbreak and the other field strains. This difference was comparable with the differences among the various Clostridia species included in the study. Characterization by MALDI TOF confirmed that BoNT-producing Clostridia isolated from animals are closely related and indistinguishable at the species level from Clostridium haemolyticum and Clostridium novyi reference strains. On the contrary, there seem to be substantial differences among chimeric and some non-chimeric type C strains.