43 research outputs found
CRISPR–cas loci profiling of Cronobacter sakazakii pathovars
Aim: Cronobacter sakazakii sequence types 1, 4, 8 and 12 are associated with outbreaks of neonatal meningitis and necrotizing enterocolitis infections. However clonality results in strains which are indistinguishable using conventional methods. This study investigated the use of clustered regularly interspaced short palindromic repeats (CRISPR)–cas loci profiling for epidemiological investigations. Materials & methods: Seventy whole genomes of C. sakazakii strains from four clonal complexes which were widely distributed temporally, geographically and origin of source were profiled. Results & conclusion: All strains encoded the same type I-E subtype CRISPR–cas system with a total of 12 different CRISPR spacer arrays. This study demonstrated the greater discriminatory power of CRISPR spacer array profiling compared with multilocus sequence typing, which will be of use in source attribution during Cronobacter outbreak investigations
Draft Genome Sequence of anEnterobacterSpecies Associated with Illnesses and Powdered Infant Formula
This is the first report of the draft genome sequence of an Enterobacter species that may have been transmitted from powdered infant formula (PIF) to infants, resulting in illness. Enterobacter spp. are currently permitted in PIF, but the transmission of this strain indicates that the microbiological criteria for PIF may need revision
Diversity of O Antigens within the Genus Cronobacter: from Disorder to Order
Cronobacter species are Gram-negative opportunistic pathogens that can cause serious infections in neonates. The lipopolysaccharides (LPSs) that form part of the outer membrane of such bacteria are possibly related to the virulence of particular bacterial strains. However, currently there is no clear overview of O-antigen diversity within the various Cronobacter strains and links with virulence. In this study, we tested a total of 82 strains, covering each of the Cronobacter species. The nucleotide variability of the O-antigen gene cluster was determined by restriction fragment length polymorphism (RFLP) analysis. As a result, the 82 strains were distributed into 11 previously published serotypes and 6 new serotypes, each defined by its characteristic restriction profile. These new serotypes were confirmed using genomic analysis of strains available in public databases: GenBank and PubMLST Cronobacter. Laboratory strains were then tested using the current serotype-specific PCR probes. The results show that the current PCR probes did not always correspond to genomic O-antigen gene cluster variation. In addition, we analyzed the LPS phenotype of the reference strains of all distinguishable serotypes. The identified serotypes were compared with data from the literature and the MLST database (www.pubmlst.org/cronobacter/). Based on the findings, we systematically classified a total of 24 serotypes for the Cronobacter genus. Moreover, we evaluated the clinical history of these strains and show that Cronobacter sakazakii O2, O1, and O4, C. turicensis O1, and C. malonaticus O2 serotypes are particularly predominant in clinical cases
The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes
Background: The most common cause of Gram-negative bacterial neonatal meningitis is E. coli K1. It has a mortality rate of 10–15%, and neurological sequelae in 30– 50% of cases. Infections can be attributable to nosocomial sources, however the pre-colonisation of enteral feeding tubes has not been considered as a specific risk factor. Methods: Thirty E. coli strains, which had been isolated in an earlier study, from the residual lumen liquid and biofilms of neonatal nasogastric feeding tubes were genotyped using pulsed-field gel electrophoresis, and 7-loci multilocus sequence typing. Potential pathogenicity and biofilm associated traits were determined using specific PCR probes, genome analysis, and in vitro tissue culture assays. Results: The E. coli strains clustered into five pulsotypes, which were genotyped as sequence types (ST) 95, 73, 127, 394 and 2076 (Achman scheme). The extra-intestinal pathogenic E. coli (ExPEC) phylogenetic group B2 ST95 serotype O1:K1:NM strains had been isolated over a 2 week period from 11 neonates who were on different feeding regimes. The E. coli K1 ST95 strains encoded for various virulence traits associated with neonatal meningitis and extracellular matrix formation. These strains attached and invaded intestinal, and both human and rat brain cell lines, and persisted for 48 h in U937 macrophages. E. coli STs 73, 394 and 2076 also persisted in macrophages and invaded Caco-2 and human brain cells, but only ST394 invaded rat brain cells. E. coli ST127 was notable as it did not invade any cell lines. Conclusions: Routes by which E. coli K1 can be disseminated within a neonatal intensive care unit are uncertain, however the colonisation of neonatal enteral feeding tubes may be one reservoir source which could constitute a serious health risk to neonates following ingestion
Capsular profiling of the Cronobacter genus and the association of specific Cronobacter sakazakii and C. malonaticus capsule types with neonatal meningitis and necrotizing enterocolitis
Background: Cronobacter sakazakii and C. malonaticus can cause serious diseases especially in infants where they are associated with rare but fatal neonatal infections such as meningitis and necrotising enterocolitis.
Methods: This study used 104 whole genome sequenced strains, covering all seven species in the genus, to analyse capsule associated clusters of genes involved in the biosynthesis of the O-antigen, colanic acid, bacterial cellulose, enterobacterial common antigen (ECA), and a previously uncharacterised K-antigen.
Results: Phylogeny of the gnd and galF genes flanking the O-antigen region enabled the defining of 38 subgroups which are potential serotypes. Two variants of the colanic acid synthesis gene cluster (CA1 and CA2) were found which differed with the absence of galE in CA2. Cellulose (bcs genes) were present in all species, but were absent in C. sakazakii sequence type (ST) 13 and clonal complex (CC) 100 strains. The ECA locus was found in all strains. The K-antigen capsular polysaccharide Region 1 (kpsEDCS) and Region 3 (kpsMT) genes were found in all Cronobacter strains. The highly variable Region 2 genes were assigned to 2 homology groups (K1 and K2). C. sakazakii and C. malonaticus isolates with capsular type [K2:CA2:Cell+] were associated with neonatal meningitis and necrotizing enterocolitis. Other capsular types were less associated with clinical infections. Conclusion: This study proposes a new capsular typing scheme which identifies a possible important virulence trait associated with severe neonatal infections. The various capsular polysaccharide structures warrant further investigation as they could be relevant to macrophage survival, desiccation resistance, environmental survival, and biofilm formation in the hospital environment, including neonatal enteral feeding tubes
NEW POSSIBILITIES OF FIRE PREVENTION IN WOODEN HISTORICAL MONUMENTS. THE WATER MIST EXTINGUISHING SYSTEM
Fire poses a constant threat to historical monuments, especially wooden sacral objects. Each year statistics prepared by the State Fire Brigade services list new destroyed objects. The diminished entries in the register and inventory encompass both categories of historical monuments – mobile and immobile. For many years now, the number of fires of historical objects has maintained a steady level of about 150. The future retention of such a threat will signify that in the coming ten years some 1500 monuments will simply disappear from the map of Poland.
In 2003 the Polish market has noted the appearance of new, extremely noteworthy technological solutions specially devised for the protection of historical wooden architecture, including a permanent fire extinguishing installation.
The first installation of this sort was applied in the church of St. Sebastian in Wieliczka. The extinguishing system control was installed next to the side entrance. The water supply and pneumatic set was placed in a concrete subterranean receptacle built in the church plot, thus resolving the localisation of the hydrophores, gas cylinders, valves and other elements of water supply. The reinforced concrete chamber required an area of only 10 sq. m.
The hydrophore chamber adjoins an additional hydrant attachment. Depending on the local sources supplying the system with water its utilization may assume assorted forms. On the one hand, it makes it possible to fill the receptacles (in case of a water shortage in the course of extinguishing a fire) and, on the other hand, it can be used by special units which, upon arrival, can pump water into the whole extinguishing system.
The pipe installation is built partially of oxidized steel pipes and copper. Vertical pipes were introduced into the attic by means of a passage through the sacristy. The pipes were concealed with the battens and thus rendered them totally invisible. The church elevation contains only slightly discernible small mist nozzles. Owing to the height of the outer walls the nozzles are placed on two levels: halfway up the walls and underneath the eaves, together with heat detectors. The aesthetic execution of whole installation made it possible to avoid impairing the historical monument.
The first extremely important step towards an active protection of wooden architecture against fire has been made. The owners of historical monuments, conservators and designers have been provided with a new instrument – the water mist extinguishing system. An additional source of satisfaction is the fact that this is a Polish solution, to be taken into consideration in all plans dealing with the complex tasks of an anti-fire protection of historical monuments