RESUMEN
Characterizing microorganisms according to different criteria is useful when investigating sources of microbiological contamination in the pharmaceutical industry. The aim of this study was to characterize 38 Acinetobacter baumannii complex strains isolated from a biopharmaceutical industry by 16S rRNA sequencing, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS), multilocus sequence typing (MLST), antimicrobial susceptibility profile, biofilm formation, and sensibility to disinfectants. Thirty-three (86.9%) strains were identified by 16S rRNA gene sequencing as A. seifertii/pitti/nosocomialis/lactucae, four (10.5%) as A. baumannii, and one (2.6%) as A. vivianii/courvalini. MALDI-TOF/MS did not identify one strain, and incorrectly identified 30/37 (81.1%) strains as A. baumannii. Strains were assigned to 12 different STs, of which nine were newly defined in this study (STs 2091-2099). Twenty-six (68.4%) strains showed resistance to amikacin and gentamicin. Thirty-three (86.8%) strains were classified as moderately or strongly adherent on polystyrene. Alcohol 70%/15 min and quaternary ammonium 0.08%/20 min were not able to eliminate the biofilm formed, but sodium hypochlorite 0.1%/15 min was efficient. In conclusion, improved methods are needed to improve the identification of Acinetobacter strains in pharmaceutical industries. This organism is of particular concern as it forms recalcitrant biofilms, leading to persistence in the manufacturing environment and increased risk of product contamination.
Asunto(s)
Acinetobacter baumannii , Tipificación de Secuencias Multilocus , ARN Ribosómico 16S/genética , Acinetobacter baumannii/genética , Amicacina , Preparaciones FarmacéuticasRESUMEN
Species identification and growth rates for a collection of Cronobacter strains from clinical and non-clinical sources have been previously reported. However, advancements in DNA sequencing-based identification methods now allow for more accurate identification. Here we report the sequence types (STs) for 24 strains of Cronobacter sakazakii and examine any possible correlation between sequence type and growth rate, which could influence risk through greater pathogen multiplication and reach of infectious doses during time between formula preparation and feeding. The most common clonal complexes (CCs) identified were C. sakazakii CC1 and CC4. CC1 strains belonged to ST1 (n = 8) and ST391 (n = 1), while CC4 included ST4 (n = 4), ST255 (n = 1) and ST295 (n = 1). Three strains were found to belong to CC100 and two were found to belong to ST64. The remaining STs identified were represented by single strains. CC4 strains have a slightly not significant tendency for faster growth rates at 25 °C; however, the small sample size suggests that more strains need to be analysed to determine if this is a true result. In conclusion, the growth rates of C. sakazakii strains do not appear to be strongly correlated to ST.
Asunto(s)
Cronobacter sakazakii , Cronobacter sakazakii/genética , Cronobacter sakazakii/crecimiento & desarrollo , Fórmulas Infantiles/microbiología , Análisis de Secuencia de ADNRESUMEN
This is the first report of acute deaths in five European brown hares (Lepus europaeus) attributed to mucoid and necrotizing typhlocolitis caused by genetically different Cronobacter (C.) turicensis strains in northeastern Austria. As this opportunistic pathogen is mainly known for causing disease in immunocompromised humans and neonates, this previously unrecognized potential for a spill over from a wildlife reservoir to humans warrants further attention.
Asunto(s)
Cronobacter , Liebres , Animales , Animales Salvajes , Brotes de Enfermedades/veterinaria , Humanos , Recién NacidoRESUMEN
Members of the Cronobacter genus include food-borne pathogens that can cause infections in infants, with a mortality rate as high as 40 to 80%. The high fatality rate of Cronobacter and its isolation from numerous types of food, especially from powdered infant formula, demonstrate the serious nature of this organism. The source tracking of Cronobacter spp. and the analysis of high-frequency species from different sources are helpful for a more targeted control. Furthermore, the persistence during food processing and storage may be attributed to strong resistance of Cronobacter spp. to environment stresses such as heat, pH, and desiccation. There are many factors that support the survival of Cronobacter spp. in harsh environments, such as some genes, regulatory systems, and biofilms. Advanced detection technology is helpful for the strict monitoring of Cronobacter spp. In addition to the traditional heat treatment, many new control techniques have been developed, and the ability to control Cronobacter spp. has been demonstrated. The control of this bacteria is required not only during manufacture, but also through the selection of packaging methods to reduce postprocessing contamination. At the same time, the effect of inactivation methods on product quality and safety must be considered. This review considers the advances in our understanding of environmental stress response in Cronobacter spp. with special emphasis on its implications in food processing.
Asunto(s)
Cronobacter sakazakii , Cronobacter , Animales , Cronobacter/genética , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Fórmulas Infantiles , PolvosRESUMEN
BACKGROUND: Kitchen sponges are a major source of cross-contamination as they can transfer foodborne pathogens, infectious agents and spoilage causing microorganisms to food contact surfaces. Several studies have revealed that university students adopt poor practices regarding food safety, hygiene, and the handling of kitchen cleaning equipment. METHODS: A total of fifty kitchen sponges were collected along with a questionnaire addressing social demographics and kitchen sponge usage by students living at the University of Sharjah dormitories. The effect of storage (3 and 10 days) on the microbial population of kitchen sponges at room temperature (21 °C) was assessed. Enterobacteriaceae isolated from sponges were identified and their antibiotic resistance determined. RESULTS: Student responses revealed that kitchen sponges used to clean food contact surfaces were also used to clean the oven (32%), sink (26%), refrigerator (10%), and to clean spills on the floor (4%). Kitchen sponges contained high counts of mesophilic aerobic bacteria (7.9 log10/cm3), coliform (7.2 log10/cm3), Enterobacteriaceae (7.3 log10/cm3) and yeasts and molds (7.0 log10/cm3). After storage of the sponges at room temperature (21 °C) for 3 and 10 days, the number of mesophilic aerobic bacteria, coliform, Enterobacteriaceae and yeasts and molds decreased by 0.4 and 1.3 log10/cm3, 0.7 and 1.4 log10/cm3, 0.4 and 1.1 log10/cm3, and 0.6 and 1.3 log10/cm3, respectively. The most frequently isolated Enterobacteriaceae were Enterobacter cloacae (56%) and Klebsiella oxytoca (16%). All E. cloacae isolates were resistant to amoxicillin, cefalotin, cefoxitin and cefuroxime axetil. CONCLUSIONS: This study showed that students living in dormitories lacked good hygienic practices and were at increased risk of food poisoning. Kitchen sponges were highly contaminated with potentially pathogenic bacteria which could be transferred from the general kitchen environment to food contact surfaces and consequently lead to food contamination.
Asunto(s)
Enterobacteriaceae/aislamiento & purificación , Contaminación de Alimentos/estadística & datos numéricos , Manipulación de Alimentos/estadística & datos numéricos , Microbiología de Alimentos , Inocuidad de los Alimentos , Estudiantes/psicología , Universidades/estadística & datos numéricos , Adulto , Recuento de Colonia Microbiana , Femenino , Humanos , Masculino , Estudiantes/estadística & datos numéricos , Emiratos Árabes Unidos , Adulto JovenRESUMEN
Cronobacter sakazakii has been documented as a cause of life-threating infections, predominantly in neonates. We conducted a multicenter study to assess the occurrence of C. sakazakii across Europe and the extent of clonality for outbreak detection. National coordinators representing 24 countries in Europe were requested to submit all human C. sakazakii isolates collected during 2017 to a study center in Austria. Testing at the center included species identification by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, subtyping by whole-genome sequencing (WGS), and determination of antimicrobial resistance. Eleven countries sent 77 isolates, including 36 isolates from 2017 and 41 historical isolates. Fifty-nine isolates were confirmed as C. sakazakii by WGS, highlighting the challenge of correctly identifying Cronobacter spp. WGS-based typing revealed high strain diversity, indicating absence of multinational outbreaks in 2017, but identified 4 previously unpublished historical outbreaks. WGS is the recommended method for accurate identification, typing, and detection of this pathogen.
Asunto(s)
Cronobacter sakazakii , Infecciones por Enterobacteriaceae/epidemiología , Infecciones por Enterobacteriaceae/microbiología , Antibacterianos/farmacología , Cronobacter sakazakii/clasificación , Cronobacter sakazakii/efectos de los fármacos , Cronobacter sakazakii/genética , Farmacorresistencia Bacteriana , Infecciones por Enterobacteriaceae/historia , Europa (Continente)/epidemiología , Genoma Bacteriano , Genómica/métodos , Historia del Siglo XXI , Humanos , Recién Nacido , Masculino , Pruebas de Sensibilidad Microbiana , Tipificación Molecular , Tipificación de Secuencias Multilocus , Filogenia , Vigilancia en Salud Pública , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Secuenciación Completa del GenomaRESUMEN
Antibiotics are a key tool used nowadays in health care industry to fight against bacterial infections; however, repeated antibiotic use or misuses, have led to bacterial resistance, causing significant threats for many people with common bacterial infections. The use of probiotics to enhance gastrointestinal health has been proposed for many years. In recent years, there has been an increasing interest in the use of probiotic bacteria as alternatives for antibiotics for preventing or treating various intestinal infections. Several important underlying mechanisms responsible for the antagonistic effects of probiotics on different microorganisms include: (1) competitive exclusion for adhesion sites and nutritional sources; (2) secretion of antimicrobial substances; (3) enhancement of intestinal barrier function; and (4) immunomodulation. However, their mode of action is not very well understood and therefore a clearer understanding of these mechanisms is necessitated. This will enable appropriate probiotic strains to be selected for particular applications and may reveal new probiotic functions. The goal of this review was to highlight some studies from literature describing the probiotic interaction with several major foodborne pathogens, as well as explore the mechanisms for such probiotic-pathogen interaction. The review will conclude by presenting future perspective and challenges of probiotic application in food products.
Asunto(s)
Infecciones Bacterianas/prevención & control , Enfermedades Transmitidas por los Alimentos/prevención & control , Tracto Gastrointestinal/microbiología , Probióticos/uso terapéutico , Antibacterianos , Antibiosis , HumanosRESUMEN
Cronobacter malonaticus is a member of the genus Cronobacter which is considered an opportunistic pathogen. The significance of C. malonaticus has recently increased since it was documented to be involved in several serious neonatal infections. However, the virulence factors of C. malonaticus including their ability to adhere, invade and overcome host barriers have not been studied before. Unlike previous Cronobacter research, this study is mainly focused on C. malonaticus and is aimed to investigate its virulence characteristics that enable this species to cause adult and neonatal infections. Altogether, 20 strains were included in this study (19 clinical and one environmental strain). Our data showed that the clinical C. malonaticus has an ability to adhere and invade Caco-2, HBMEC, A549 and T24 cell lines. Moreover, the result showed that certain strains of C. malonaticus (including 1827 and 2018) were able to persist well in macrophages. However, ST7 strains 1827 and 2018 proved to be the most invasive strains among all used strains. The CDC strain 1569 (ST307) which was isolated from the blood of a fatal neonatal case showed also significant results in this study as it was able to invade all used human cells and survive and replicate within microphages. Finally, the findings of this study confirm the potential ability of C. malonaticus to cause serious infections in neonates or adults such as necrotising enterocolitis, meningitis, bacteraemia, pneumonia and urinary tract infection.
Asunto(s)
Adhesión Bacteriana , Cronobacter/aislamiento & purificación , Cronobacter/patogenicidad , Endocitosis , Infecciones por Enterobacteriaceae/microbiología , Línea Celular , Células Epiteliales/microbiología , Humanos , Macrófagos/microbiología , Modelos Biológicos , VirulenciaRESUMEN
The air in a powdered infant formula (PIF) factory is a potential transfer medium for microorganisms. In this study, air samples from 6 main processing areas, almost covering the whole PIF processing line and 1 outdoor location, were collected from a PIF manufacturing plant during the winter and summer periods. A cultivation-based and an Illumina (San Diego, CA) high-throughput 16S rRNA sequencing method was used to investigate the community structures and distributions of bacteria in the air. High microbial diversity (25 genera, 56 species), with a dominant community including Staphylococcus, Bacillus, Acinetobacter, and Kocuria, was found by the cultivation-based method. Moreover, 104 genera were obtained from all samples by high-throughput sequencing methods. Lactococcus (32.3%), Bacillus (29.6%), and Staphylococcus (14.0%) were the preponderant genera. The indices from high-throughput sequencing results indicated that the bacterial community of the air samples was highly diverse. Significant differences in the diversity and distribution at 6 sampling locations were revealed using the 2 methods. In particular, the packaging process contained the highest proportion (39.4%) of isolated strains. The highest diversity in bacterial community structure was found in the outdoor location. More bacterial isolates and higher community diversity were observed in the summer samples compared with the winter samples. In addition, some pathogens, such as Acinetobacter baumannii, Bacillus cereus, and Staphylococcus cohnii, were mainly found in the large bag filling process, can filling, and packaging process areas. The present study provides greater insight into the microbial community and identifies potential sources of air contamination in PIF production environments and can serve as a guide to reduce the risk of microbial contamination in the production of PIF.
Asunto(s)
Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Fórmulas Infantiles/microbiología , ARN Ribosómico 16S/análisis , Animales , Bacterias , Humanos , Lactante , Recién Nacido , PolvosRESUMEN
BACKGROUND: Microbiological criteria applied to powdered infant formula (PIF) require the absence of all Cronobacter spp. Consequently, misidentification of isolates from finished products can lead to significant financial losses for manufacturers and could increase the risk of neonatal infection. Biochemical identification of suspect isolates using commercially available test panels is recommended for use by PIF manufacturers by both the US FDA and ISO standard methods for Cronobacter species; however, phenotyping can be unreliable, particularly for a genus such as Cronobacter where the taxonomy has been subject to frequent changes. This study compared the predicted identification by commonly used phenotyping kits (API20E and ID32E) for over 240 strains of Cronobacter from diverse sources, which had been identified using DNA sequence analysis. In 2015, the databases associated with the API20E and ID32E biochemical test panels were updated, including the recognition of the Cronobacter genus. Thus, the identifications from multiple versions the databases were compared to each other and to identifications based on DNA sequencing methods. RESULTS: Using previous versions of the API20E database, 90.0 % of strains (216/240) resulted in a match for the species identification; however, version 5.0 produced matches for only 82.3 % of strains (237/288). Similarly, the update to version 4.0 in the ID32E database caused the percentage of matches to drop from 88.9 % (240/270) to 43.2 % (139/322). A smaller study showed that the Vitek GN system identified all 14 strains, belonging all seven Cronobacter species, as members of the 'C. sakazakii group,' but also attributed three strains of Franconibacter helveticus and F. pulveris to this group. In silco analysis of a PCR-based method targeting ompA predicted that amplification would only occur with Cronobacter species and this method may be a feasible alternative to biochemical phenotyping. CONCLUSIONS: These results indicate that commercially available biochemical test panels are not sufficiently reliable for speciation of Cronobacter isolates. Although DNA-sequence based methods would be the more reliable approach; however, this is not currently feasible for many food microbiology laboratories. Instead, a previously published PCR-based method targeting ompA is suggested as an alternative for identification of Cronobacter species based on in silico analysis.
Asunto(s)
Técnicas de Tipificación Bacteriana/métodos , Cronobacter/clasificación , Cronobacter/fisiología , Proteínas de la Membrana Bacteriana Externa/genética , Técnicas de Tipificación Bacteriana/instrumentación , Clasificación , Simulación por Computador , Cronobacter/aislamiento & purificación , ADN Bacteriano/genética , Bases de Datos de Ácidos Nucleicos , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Genotipo , Fórmulas Infantiles/microbiología , Fenotipo , Reacción en Cadena de la Polimerasa/métodos , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
Cronobacter sakazakii is the most frequently clinically isolated species of the Cronobacter genus. However the virulence factors of C. sakazakii including their ability to overcome host barriers remains poorly studied. In this study, ten clinical isolates of C. sakazakii were assessed for their ability to invade and translocate through human colonic carcinoma epithelial cells (Caco-2) and human brain microvascular endothelial cells (HBMEC). Their ability to avoid phagocytosis in human macrophages U937 and human brain microglial cells was investigated. Additionally, they were tested for serum sensitivity and the presence of the Cronobacter plasminogen activation gene (cpa) gene, which is reported to confer serum resistance. Our data showed that the clinical C. sakazakii strains invaded and translocated through Caco-2 and HBMEC cell lines and some strains showed significantly higher levels of invasion and translocation. Moreover, C. sakazakii was able to persist and even multiply in phagocytic macrophage and microglial cells. All strains, except one, were able to withstand human serum exposure, the single serum sensitive strain was also the only one which did not encode for the cpa gene. These results demonstrate that C. sakazakii clinical isolates are able to overcome host barriers and evade the host immune response indicating their capacity to cause diseases such as necrotizing enterocolitis (NEC) and meningitis. Our data showed for the first time the ability of C. sakazakii clinical isolates to survive and multiply within human microglial cells. Additionally, it was shown that C. sakazakii clinical strains have the capacity to translocate through the Caco-2 and HBMEC cell lines paracellularly.
Asunto(s)
Cronobacter sakazakii/inmunología , Cronobacter sakazakii/patogenicidad , Infecciones por Enterobacteriaceae/inmunología , Infecciones por Enterobacteriaceae/microbiología , Células CACO-2 , Técnicas de Cultivo de Célula , Línea Celular , Cronobacter sakazakii/genética , Cronobacter sakazakii/aislamiento & purificación , Células Endoteliales/microbiología , Infecciones por Enterobacteriaceae/genética , Células Epiteliales/microbiología , Humanos , Macrófagos/inmunología , Macrófagos/microbiología , Macrófagos/patología , Meningitis/microbiología , Pruebas de Sensibilidad Microbiana , Microglía/microbiología , Microglía/patología , Factores de Virulencia/genética , Factores de Virulencia/inmunología , Factores de Virulencia/metabolismoRESUMEN
Cronobacter spp. (formerly defined as Enterobacter sakazakii) are opportunistic bacterial pathogens of both infants and adults. In this study, we analyzed 70 Cronobacter isolates from powdered infant formula (PIF) and an infant formula production facility in China to determine possible contamination routes. The strains were profiled by multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), PCR-based O-antigen serotyping, and ompA and rpoB sequence analyses. The isolates were primarily Cronobacter sakazakii (66/70) or Cronobacter malonaticus (4/70). The strains were divided into 38 pulsotypes (PTs) using PFGE and 19 sequence types (STs) by MLST. In contrast, rpoB and ompA sequence analyses divided the strains into 10 overlapping clusters each. PCR serotyping of the 66 C. sakazakii and 4 C. malonaticus strains resulted in the identification of four C. sakazakii serotypes (O1, O2, O4, and O7) and a single C. malonaticus serotype, O2. The dominant C. sakazakii sequence types from PIF and an infant formula production factory in China were C. sakazakii clonal complex 4 (CC4) (n = 19), ST1 (n = 14), and ST64 (n = 11). C. sakazakii CC4 is a clonal lineage strongly associated with neonatal meningitis. In the process of manufacturing PIF, the spray-drying, fluidized-bed-drying, and packing areas were the main areas with Cronobacter contamination. C. sakazakii strains with the same pulsotypes (PT3 and PT2) and sequence types (ST1 and ST64) were isolated both from processing equipment and from the PIF finished product.
Asunto(s)
Cronobacter/clasificación , Cronobacter/aislamiento & purificación , Microbiología Ambiental , Fórmulas Infantiles/microbiología , Proteínas de la Membrana Bacteriana Externa/genética , China , Análisis por Conglomerados , Cronobacter/genética , ADN Bacteriano/química , ADN Bacteriano/genética , ARN Polimerasas Dirigidas por ADN/genética , Electroforesis en Gel de Campo Pulsado , Manipulación de Alimentos , Genotipo , Técnicas de Genotipaje , Humanos , Datos de Secuencia Molecular , Tipificación de Secuencias Multilocus , Antígenos O/genética , Reacción en Cadena de la Polimerasa , Homología de SecuenciaRESUMEN
A re-evaluation of the taxonomic position of two strains, 1383(T) and 2249, isolated from poppy seeds and tea leaves, which had been identified as Siccibacter turicensis (formerly Cronobacter zurichensis ), was carried out. The analysis included phenotypic characterization, 16S rRNA gene sequencing, multilocus sequence analysis (MLSA) of five housekeeping genes (atpD, fusA, glnS, gyrB and infB; 2034 bp) and ribosomal MLSA (53 loci; 22â511 bp). 16S rRNA gene sequence analysis and MLSA showed that the strains formed an independent phylogenetic lineage, with Siccibacter turicensis LMG 23730(T) as the closest neighbour. Average nucleotide identity analysis and phenotypic analysis confirmed that these strains represent a novel species, for which the name Siccibacter colletis sp. nov. is proposed. The type strain is 1383(T) (â=âNCTC 14934(T)â=âCECT 8567(T)â=âLMG 28204(T)). An emended description of Siccibacter turicensis is also provided.
Asunto(s)
Camellia sinensis/microbiología , Enterobacteriaceae/clasificación , Papaver/microbiología , Filogenia , Técnicas de Tipificación Bacteriana , ADN Bacteriano/genética , Enterobacteriaceae/genética , Enterobacteriaceae/aislamiento & purificación , Genes Bacterianos , Datos de Secuencia Molecular , Tipificación de Secuencias Multilocus , Hibridación de Ácido Nucleico , Hojas de la Planta/microbiología , ARN Ribosómico 16S/genética , Semillas/microbiología , Análisis de Secuencia de ADNRESUMEN
Neonates in intensive care units often require supporting medical devices and antibiotic treatment. The intensive care treatment combined with their immature immune system, the increased permeability of mucosa, and the undeveloped microflora of the gut may render the neonates highly vulnerable to colonisation and subsequent infections when exposed to opportunistic pathogens. These infections may not only be local gastrointestinal infections, but also systematic following translocation from the gastrointestinal system. This could be particularly alarming considering that common antibiotics may not be effective if the causative strain is multi-drug resistant.This chapter reviews our information on the microbial colonization of neonatal feeding tubes. The range of organisms which have been recovered are wide, and while primarily bacterial, fungi such as Candida have also been found. The bacteria are principally Staphylococcus spp. and Enterobacteriaceae. The Enterobacteriaceae isolates are predominantly Enterobacter cancerogenus, Serratia marcescens, Enterobacter hormaechei, Escherichia coli and Klebsiella pneumoniae. Many of these isolates encode for antibiotic resistance; E. hormaechei (ceftazidine and cefotaxime) and S. marcescens strains (amoxicillin and co-amoxiclav).
Asunto(s)
Infecciones Bacterianas/microbiología , Biopelículas/crecimiento & desarrollo , Nutrición Enteral/instrumentación , Consorcios Microbianos/fisiología , Micosis/microbiología , Infecciones Bacterianas/etiología , Infecciones Bacterianas/prevención & control , Nutrición Enteral/efectos adversos , Contaminación de Equipos/prevención & control , Contaminación de Alimentos/prevención & control , Humanos , Fórmulas Infantiles/administración & dosificación , Recién Nacido , Micosis/etiología , Micosis/prevención & controlRESUMEN
BACKGROUND: Following the association of Cronobacter spp. to several publicized fatal outbreaks in neonatal intensive care units of meningitis and necrotising enterocolitis, the World Health Organization (WHO) in 2004 requested the establishment of a molecular typing scheme to enable the international control of the organism. This paper presents the application of Next Generation Sequencing (NGS) to Cronobacter which has led to the establishment of the Cronobacter PubMLST genome and sequence definition database (http://pubmlst.org/cronobacter/) containing over 1000 isolates with metadata along with the recognition of specific clonal lineages linked to neonatal meningitis and adult infections RESULTS: Whole genome sequencing and multilocus sequence typing (MLST) has supports the formal recognition of the genus Cronobacter composed of seven species to replace the former single species Enterobacter sakazakii. Applying the 7-loci MLST scheme to 1007 strains revealed 298 definable sequence types, yet only C. sakazakii clonal complex 4 (CC4) was principally associated with neonatal meningitis. This clonal lineage has been confirmed using ribosomal-MLST (51-loci) and whole genome-MLST (1865 loci) to analyse 107 whole genomes via the Cronobacter PubMLST database. This database has enabled the retrospective analysis of historic cases and outbreaks following re-identification of those strains. CONCLUSIONS: The Cronobacter PubMLST database offers a central, open access, reliable sequence-based repository for researchers. It has the capacity to create new analysis schemes 'on the fly', and to integrate metadata (source, geographic distribution, clinical presentation). It is also expandable and adaptable to changes in taxonomy, and able to support the development of reliable detection methods of use to industry and regulatory authorities. Therefore it meets the WHO (2004) request for the establishment of a typing scheme for this emergent bacterial pathogen. Whole genome sequencing has additionally shown a range of potential virulence and environmental fitness traits which may account for the association of C. sakazakii CC4 pathogenicity, and propensity for neonatal CNS.
Asunto(s)
Cronobacter/genética , Genoma Bacteriano , Tipificación de Secuencias Multilocus , Algoritmos , Cronobacter/clasificación , Cronobacter sakazakii/clasificación , Cronobacter sakazakii/genética , Bases de Datos Genéticas , Ligamiento Genético , Sitios Genéticos , Genotipo , Secuenciación de Nucleótidos de Alto Rendimiento , Filogenia , Análisis de Secuencia de ADNRESUMEN
The genus Arcobacter is composed of 17 species which have been isolated from various sources. Of particular interest are A. butzleri, A. cryaerophilus, and A. skirrowii, as these have been associated with human cases of diarrhea, the probable transmission routes being through the ingestion of contaminated drinking water and food. To date, only limited studies of virulence traits in this genus have been undertaken. The present study used 60 Arcobacter strains isolated from different sources, representing 16 of the 17 species of the genus, to investigate their ability to adhere to and invade the human intestinal cell line Caco-2. In addition, the presence of five putative virulence genes (ciaB, cadF, cj1349, hecA, and irgA) was screened for in these strains by PCR. All Arcobacter species except A. bivalviorum and Arcobacter sp. strain W63 adhered to Caco-2 cells, and most species (10/16) were invasive. The most invasive species were A. skirrowii, A. cryaerophilus, A. butzleri, and A. defluvii. All invasive strains were positive for ciaB (encoding a putative invasion protein). Other putative virulence genes were present in other species, i.e., A. butzleri (cadF, cj1349, irgA, and hecA), A. trophiarum (cj1349), A. ellisii (cj1349), and A. defluvii (irgA). No virulence genes were detected in strains which showed little or no invasion of Caco-2 cells. These results indicate that many Arcobacter species are potential pathogens of humans and animals.
Asunto(s)
Arcobacter/genética , Arcobacter/patogenicidad , Adhesión Bacteriana , Proteínas Bacterianas/genética , Arcobacter/clasificación , Arcobacter/fisiología , Proteínas Bacterianas/metabolismo , Células CACO-2 , Humanos , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , Análisis de Secuencia de ADN , Especificidad de la Especie , VirulenciaRESUMEN
Cronobacter spp. (formerly Enterobacter sakazakii) can be isolated from a wide range of foods and environments, and its association with neonatal infections has drawn considerable attention from regulatory authorities. The principle route of neonatal infection has been identified as the ingestion of contaminated infant formula. A number of methods have been developed to identify Cronobacter spp., however these were before the most recent (2012) taxonomic revision of the genus into seven species. In this study, phenotyping, protein profiling and molecular methods were used to identify Cronobacter strains which had been recently isolated from ingredients used in the preparation of infant formula. Pulsed field gel electrophoresis revealed that different Cronobacter strains had been recovered from the same food products. All isolates were identified as Cronobacter sakazakii according to four genus specific PCR-probes and protein profiling using MALDI-TOF analysis. However, 16S rDNA sequence analyses and fusA allele sequencing gave more accurate identification: four strains were C. sakazakii, one strain was Cronobacter malonaticus and the remaining strain was Cronobacter universalis. Multilocus sequence typing showed the strains were different sequence types. These results demonstrate the presence of different Cronobacter species in food ingredients used in the preparation of infant formula, and also the need for molecular identification and profiling methods to be revised according to taxonomic revisions.
Asunto(s)
Cronobacter/clasificación , Cronobacter/genética , Contaminación de Alimentos , Microbiología de Alimentos , Fórmulas Infantiles , Técnicas de Tipificación Bacteriana , Secuencia de Bases , Cronobacter/aislamiento & purificación , ADN Bacteriano/genética , Genotipo , Humanos , Lactante , Factor G de Elongación Peptídica/genética , Fenotipo , Análisis por Matrices de Proteínas , ARN Ribosómico 16S/análisis , Análisis de Secuencia de ADN , Espectrometría de Masa por Láser de Matriz Asistida de Ionización DesorciónRESUMEN
The accuracy of the Cronobacter biotyping scheme was compared with the 7-loci multilocus sequence typing scheme. Biotyping did not reliably assign species level identification, as only half (17/31) of the biotype variants were unique to any of the seven Cronobacter species and the remaining biotypes were shared across the genus.
Asunto(s)
Cronobacter/clasificación , Cronobacter/genética , Tipificación de Secuencias Multilocus/métodos , ADN Bacteriano/química , Variación Genética , Especificidad de la EspecieRESUMEN
A re-evaluation of the taxonomic position of five strains, one assigned to Cronobacter sakazakii (strain 1330(T), isolated from spiced meat purchased in Slovakia), two previously assigned to Cronobacter genomospecies 1 (strains NCTC 9529(T) and 731, isolated from water and a leg infection, respectively) and two previously assigned to Cronobacter turicensis (strains 96 and 1435, isolated from onion powder and rye flour, respectively) was carried out. The analysis included phenotypic characterization, 16S rRNA gene sequencing and multilocus sequence analysis (MLSA) of seven housekeeping genes (atpD, fusA, glnS, gltB, gyrB, infB, ppsA; 3036 bp). 16S rRNA gene sequence analysis and MLSA showed that strain 1330(T) formed an independent phylogenetic lineage in the MLSA, with Cronobacter dublinensis LMG 23823(T) as the closest neighbour. DNA-DNA reassociation and phenotypic analysis revealed that strain 1330(T) represented a novel species, for which the name Cronobacter condimenti sp. nov. is proposed (type strain 1330(T) = CECT 7863(T) = LMG 26250(T)). Strains NCTC 9529(T), 731, 96 and 1435 clustered together within an independent phylogenetic lineage, with C. turicensis LMG 23827(T) as the closest neighbour in the MLSA. DNA-DNA reassociation and phenotypic analysis confirmed that these strains represent a novel species, for which the name Cronobacter universalis sp. nov. is proposed (type strain NCTC 9529(T) = CECT 7864(T) = LMG 26249(T)).
Asunto(s)
Cronobacter/clasificación , Cronobacter/aislamiento & purificación , Infecciones por Enterobacteriaceae/microbiología , Microbiología de Alimentos , Pierna/microbiología , Productos de la Carne/microbiología , Microbiología del Agua , Niño , Cronobacter/genética , ADN Bacteriano/genética , Humanos , Masculino , Datos de Secuencia Molecular , Filogenia , ARN Ribosómico 16S/genética , EslovaquiaRESUMEN
A 7-loci (3,036 nt) multilocus sequence typing scheme was applied to 41 clinical isolates of Cronobacter sakazakii. Half (20/41) of the C. sakazakii strains were sequence type (ST) 4, and 9/12 meningitis isolates were ST4. C. sakazakii ST4 appears to be a highly stable clone with a high propensity for neonatal meningitis.