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Leafy greens are a significant source of produce-related Shiga toxin-producing Escherichia coli (STEC) outbreaks in the United States, with agricultural water often implicated as a potential source. Current FDA outbreak detection protocols are time-consuming and rely on sequencing methods performed in costly equipment. This study evaluated the potential of Oxford Nanopore Technologies (ONT) with Q20+ chemistry as a cost-effective, rapid, and accurate method for identifying and clustering foodborne pathogens. The study focuses on assessing whether ONT Q20+ technology could facilitate near real-time pathogen identification, including SNP differences, serotypes, and antimicrobial resistance genes. This pilot study evaluated different combinations of two DNA extraction methods (Maxwell RSC Cultured Cell DNA kit and Monarch high molecular weight extraction kits) and two ONT library preparation protocols (ligation and the rapid barcoding sequencing kit) using five well-characterized strains representing diverse foodborne pathogens. High-quality, closed bacterial genomes were obtained from all combinations of extraction and sequencing kits. However, variations in assembly length and genome completeness were observed, indicating the need for further optimization. In silico analyses demonstrated that Q20+ nanopore sequencing chemistry accurately identified species, genotype, and virulence factors, with comparable results to Illumina sequencing. Phylogenomic clustering showed that ONT assemblies clustered with reference genomes, though some indels and SNP differences were observed, likely due to sequencing and analysis methodologies rather than inherent genetic variation. Additionally, the study evaluated the impact of a change in the sampling rates from 4 kHz (260 bases pair second) to 5 kHz (400 bases pair second), finding no significant difference in sequencing accuracy. This evaluation workflow offers a framework for evaluating novel technologies for use in surveillance and foodborne outbreak investigations. Overall, the evaluation demonstrated the potential of ONT Q20+ nanopore sequencing chemistry to assist in identifying the correct strain during outbreak investigations. However, further research, validation studies, and optimization efforts are needed to address the observed limitations and fully realize the technology’s potential for improving public health outcomes and enabling more efficient responses to foodborne disease threats.

Background. Nosocomial bloodstream infections (BSIs) are important causes of morbidity and mortality in the United States. Methods. Data from a nationwide, concurrent surveillance study (Surveillance and Control of Pathogens of Epidemiological Importance [SCOPE]) were used to examine the secular trends in the epidemiology and microbiology of nosocomial BSIs. Results. Our study detected 24,179 cases of nosocomial BSI in 49 US hospitals over a 7-year period from March 1995 through September 2002 (60 cases per 10,000 hospital admissions). Eighty-seven percent of BSIs were monomicrobial. Gram-positive organisms caused 65% of these BSIs, gram-negative organisms caused 25%, and fungi caused 9.5%. The crude mortality rate was 27%. The most-common organisms causing BSIs were coagulase-negative staphylococci (CoNS) (31% of isolates), Staphylococcus aureus (20%), enterococci (9%), and Candida species (9%). The mean interval between admission and infection was 13 days for infection with Escherichia coli, 16 days for S. aureus, 22 days for Candida species and Klebsiella species, 23 days for enterococci, and 26 days for Acinetobacter species. CoNS, Pseudomonas species, Enterobacter species, Serratia species, and Acinetobacter species were more likely to cause infections in patients in intensive care units (P < .001). In neutropenic patients, infections with Candida species, enterococci, and viridans group streptococci were significantly more common. The proportion of S. aureus isolates with methicillin resistance increased from 22% in 1995 to 57% in 2001 (P < .001, trend analysis). Vancomycin resistance was seen in 2% of Enterococcus faecalis isolates and in 60% of Enterococcus faecium isolates. Conclusion. In this study, one of the largest multicenter studies performed to date, we found that the proportion of nosocomial BSIs due to antibiotic-resistant organisms is increasing in US hospitals.

This study evaluates Salmonella contamination in feed mill production facilities over a 12-year period, analyzing collection events from 12 facilities predominantly located in the southeastern United States. The genomic data reveals a historical contamination rate, with 20% of collection events testing positive for Salmonella . Utilizing next generation sequencing this study evaluated the genetic diversity in the different facilities to determine whether the Salmonella serovars that were found are transient or resident. Salmonella serovars Montevideo, Ruiru, and Senftenberg were frequently detected, with Ruiru showing a particularly high predominance across multiple facilities, suggesting possible common sources of contamination including regional fishing waters and shared additives. The study also highlights the role of transportation and storage methods as a possible cause of cross-contamination. Future research should focus on identifying specific contamination sources and optimizing control measures to reduce Salmonella risks in fish meal production.

Reference methods for microbiological safety assessments of cosmetics rely on culture methods that reveal colonies of live microorganisms on growth media. Rapid molecular technologies, such as qPCR, detects the presence of target DNA in samples from dead and viable cells. DNA intercalating dyes, such as propidium monoazide (PMAxx), are capable of restricting PCR amplification to viable microbial cells. Here we developed singleplex and multiplex real time (qPCR) assays for the detection of  Bacillus cereus  ( B. cereus ) using 16S rRNA and phosphatidylcholine-specific phospholipase C (PLC) gene specific sequences coupled with PMAxx. The limit of detection was determined to be ~ 1 log CFU/ml for 16S rRNA and 3 log CFU/ml for PLC detection in pure culture using an eye shadow isolate,  B. cereus  3A. We assessed the inclusivity and exclusivity of our qPCR assays using 212 strains, including 143 members of  B. cereus , 38 non-  B. cereus . and 31 non- Bacillus  species; inclusivity was 100% for the 16S rRNA and 97.9% for the PLC targets; the exclusivity was 100% for 16S rRNA and 98.6% for PLC targets. These qPCR assays were then used to assess samples of commercial cosmetics: one set of liquid face toners (N = 3), artificially contaminated with B. cereus 3A, and one set of powdered cosmetics (N = 8), previously determined to be contaminated with B. cereus . For some samples, test portions were analyzed by qPCR in parallel, with and without PMAxx treatment. All test portions were simultaneously streaked on BACARA plates to confirm viable cells of  B. cereus , according to the culture method. We found no difference in sensitivity between the singleplex and the multiplex qPCR assays ( P  > 0.05). Inoculated samples that did not recover  B. cereus  on plates still showed amplification of the DNA targets. However, that amplification was significantly delayed in PMAxx –treated samples ( P  < 0.0001) with C T  value differences of 7.82 for 16S rRNA and 7.22 for PLC. Likewise, amplification delay was significant ( P  < 0.0001) with inoculated samples that recovered  B. cereus  on plates with C T  value differences of 2.96 and 2.36 for 16S rRNA and PLC, respectively, demonstrating the presence of dead cells in the samples. All our qPCR results correlated with detection on BACARA plates (kappa, k = 0.99), independently of the presence of PMAxx in the PCR assays. Nevertheless, the amplification threshold with PMAxx dyes was significantly higher than the non-PMAxx dyes. Our findings confirm qPCR can be used for more rapid detection of microorganisms in cosmetics, including  B. cereus , and selective detection of viable cells can be improved using PMAxx dyes.

Background The Bacillus cereus group, also known as B. cereus sensu lato (s.l.) contains ubiquitous spore-forming bacteria found in the environment including strains from the B. cereus sensu stricto (s.s.) species. They occur naturally in a wide range of raw materials and in consumer products. Characterizing isolates that have survived in consumer products allows us to better understand the mechanisms that permit spores to persist and potentially cause illness. Here we characterize the draft genome sequence of B. cereus s. s. 3A-ES, originally isolated from eye shadow and since investigated in several cosmetic studies and compared it to other top ten published complete genome sequences of B. cereus s.l . members. Results The draft genome sequence of B. cereus s.s. 3A ES consisted of an average of 90 contigs comprising approximately 5,335,727 bp and a GC content of 34,988%, and with 5509 predicted coding sequences. Based on the annotation statistics and comparison to other genomes within the same species archived in the Pathosystems Resource Integration Center (PATRIC), this genome “was of good quality. Annotation of B. cereus s.s. 3A ES revealed a variety of subsystem features, virulence factors and antibiotic resistant genes. The phylogenetic analysis of ten B. cereus group members showed B. cereus s.s. 3A-ES to be a closely related homolog of B. cereus s.s. ATCC 14,579, an established reference strain that is not adapted for cosmetic microbiological studies. Survival of 3A-ES in eye shadow could be linked to predicted stress-response genes and strengthened by additional stress-response genes such as VanB-type, VanRB, CAT15/16, BcrA, BcrB, Lsa(B), and recA that are lacking in B. cereus s.s. ATCC 14,579. Conclusion Our genomic analysis of B. cereus s.s. 3A-ES revealed genes, which may allow this bacterium to withstand the action of preservatives and inhibitors in cosmetics, as well as virulence factors that could contribute to its pathogenicity. Having a well-characterized strain obtained from eye-shadow may be useful for establishing a reference strain for cosmetics testing.

Moonlighting Toxic shock syndrome is a rare, potentially fatal illness that can be caused by the release of toxins from Staphylococcus bacteria. The toxic particles are encoded by discrete genetic units called pathogenicity islands, which reside passively in the host chromosome, under the control of the global repressor Stl, unless activated by a helper phage. It is now shown that a non-essential and specific protein from the helper phage 80α is responsible for de-repression of the pathogenicity island, thereby providing the mechanism for the first step of its mobilization. The proteins involved are 'moonlighters', because they have two different and genetically distinct activities. Through a remarkable evolutionary adaptation, various related pathogenicity islands co-opt entirely unrelated phage proteins to aid in their mobilization. Staphylococcal superantigens can lead to toxic shock syndrome. They are encoded on pathogenicity islands and with the aid of helper phages can be excised and packaged into highly transmissable phage particles. Here it is shown that a specific, non-essential helper phage protein is responsible for derepression of the pathogenicity island, thereby providing the mechanism for the first step of its mobilization. Staphylococcal superantigen-carrying pathogenicity islands (SaPIs) are discrete, chromosomally integrated units of ∼15 kilobases that are induced by helper phages to excise and replicate. SaPI DNA is then efficiently encapsidated in phage-like infectious particles, leading to extremely high frequencies of intra- as well as intergeneric transfer 1 , 2 , 3 . In the absence of helper phage lytic growth, the island is maintained in a quiescent prophage-like state by a global repressor, Stl, which controls expression of most of the SaPI genes 4 . Here we show that SaPI derepression is effected by a specific, non-essential phage protein that binds to Stl, disrupting the Stl–DNA complex and thereby initiating the excision-replication-packaging cycle of the island. Because SaPIs require phage proteins to be packaged 5 , 6 , this strategy assures that SaPIs will be transferred once induced. Several different SaPIs are induced by helper phage 80α and, in each case, the SaPI commandeers a different non-essential phage protein for its derepression. The highly specific interactions between different SaPI repressors and helper-phage-encoded antirepressors represent a remarkable evolutionary adaptation involved in pathogenicity island mobilization.

Although eye area cosmetics contain preservatives, contamination can still occur during or after manufacture or through use. Understanding the likelihood of bacterial survival in eye creams begins with sensitive and accurate methods for the detection of bacterial contamination; therefore, we investigated optimal culture conditions, including neutralizers, dilution broths, and selective media for the detection of Bacillus in eye cream. Samples of three different brands of eye creams were first mixed with Tween 80, Tween 20, or a blend of Tween 60 and Span 80, then neutralized and non-neutralized samples were individually inoculated with B. cereus strains, B. mycoides, a mislabeled B. megaterium, B. subtilis or B. thuringiensis at a final concentration of 5 log CFU/g. The inoculated samples, with and without neutralizers, were spiral-plated and incubated at 30 °C for 24 h to 48 h. Presumptive colonies of Bacillus were enumerated on U. S. Food and Drug Administration Bacteriological Analytical Manual (FDA-BAM) referenced agars Bacillus cereus rapid agar (BACARA) and mannitol-egg yolk-polymixin agar (MYP). Our results show significant differences among the neutralizers, plates, and products. The combination of Tryptone- Azolectin-Tween and Tween 80 (TAT and T80) produced higher levels of Bacillus, estimated at 4.18 log CFU/g compared to growth on Modified letheen broth and Tween 80, which produced 3.97 log CFU/g (P < 0.05). Colony counts of B. cereus cells on MYP agar were significantly higher, than those on BACARA agar, showing an average of 4.25 log CFU/g versus 3.84 log CFU/g, respectively (P < 0.05). The growth of the strain mislabeled B. megaterium ATCC 6458 on B. cereus selective agars BACARA and MYP agar led us to further investigations. We identified bi-pyramidal crystals among colonies of the strain, and subsequent PCR identified the cry 1 gene, indicating that strain was actually B. thuringiensis subps. kurstaki.

This multiagency report developed by the Interagency Collaboration for Genomics for Food and Feed Safety provides an overview of the use of and transition to whole genome sequencing (WGS) technology for detection and characterization of pathogens transmitted commonly by food and for identification of their sources. We describe foodborne pathogen analysis, investigation, and harmonization efforts among the following federal agencies: National Institutes of Health; Department of Health and Human Services, Centers for Disease Control and Prevention (CDC) and U.S. Food and Drug Administration (FDA); and the U.S. Department of Agriculture, Food Safety and Inspection Service, Agricultural Research Service, and Animal and Plant Health Inspection Service. We describe single nucleotide polymorphism, core-genome, and whole genome multilocus sequence typing data analysis methods as used in the PulseNet (CDC) and GenomeTrakr (FDA) networks, underscoring the complementary nature of the results for linking genetically related foodborne pathogens during outbreak investigations while allowing flexibility to meet the specific needs of Interagency Collaboration partners. We highlight how we apply WGS to pathogen characterization (virulence and antimicrobial resistance profiles) and source attribution efforts and increase transparency by making the sequences and other data publicly available through the National Center for Biotechnology Information. We also highlight the impact of current trends in the use of culture-independent diagnostic tests for human diagnostic testing on analytical approaches related to food safety and what is next for the use of WGS in the area of food safety.

This study aimed to evaluate the potential of Oxford Nanopore Technologies (ONT) GridION with Q20+ chemistry as a rapid and accurate method for identifying and clustering foodborne pathogens. The study focuses on assessing whether ONT Q20+ technology could offer near real-time pathogen identification, including SNP differences, serotypes, and antimicrobial resistance genes, to overcome the drawbacks of existing methodologies. This pilot study evaluated different combinations of two DNA extraction methods (Maxwell RSC Cultured Cell DNA kit, and Monarch high molecular weight extraction kits) and two ONT library preparation protocols (ligation and the rapid barcoding sequencing kit) using five well-characterized strains representing diverse foodborne pathogens. The results showed that any combination of extraction and sequencing kits produced high-quality closed bacterial genomes. However, there were variations in assembly length and genome completeness based on different combinations of methods, indicating the need for further optimization. in silico analyses demonstrated that the Q20+ nanopore sequencing chemistry accurately identified species, genotyped, and detected virulence factors comparable to Illumina sequencing. Phylogenomic clustering methods showed that ONT assemblies clustered with reference genomes, although some indels and SNP differences were observed. There were also differences on SNP accuracy among the different species. The observed SNP differences were likely due to sequencing and analysis processes rather than genetic variations in the sampled bacteria. The study also compared a change in the basecaller model with the previous model (SUP 4Khz 260 bps) and found no significant difference in accuracy (SUP 5Khz 400 bps). In conclusion, the evaluation of ONT Q20+ nanopore sequencing chemistry demonstrated its potential as an alternative for rapid and comprehensive bacterial genome analysis in outbreak investigations. However, further research, verification studies, and optimization efforts are needed to address the observed limitations to adopt and fully realize the impact of nanopore sequencing on public health outcomes and more efficient responses to foodborne disease threats.

Staphylococcal pathogenicity island SaPl1 is excised from genomic DNA and extrachromosomal copies are amplified during the vegetative growth of staphylococcal phage 80α. The amplified genetic element is subsequently encapsidated and transduced at very high frequency. Previous studies have demonstrated that the transducing particles have virions with tails that appear identical to those of helper phage 80α but have smaller capsids, commensurate with the smaller genome of the SaPl (Lindsay et al., 1998). The morphology of the transducing particles, coupled with the observation that the genomic sequence of SaPl1 (GenBank U93688) does not reveal any obvious phage structural proteins, has led to the hypothesis that SaPl1 is encapsidated in a virion comprised of 80α structural proteins. Analysis of SaPl1 transducing particles supports this hypothesis. Further investigation of 80α genes involved in SaPl1 mobilization was accomplished by selection of phage mutants resistant to SaPl1 interference. Two classes of SaPl1 interference resistant (sir) mutants were obtained, and point mutations were identified in two adjacent genes. In order to confirm the roles of these genes, an in-frame deletion of each candidate gene was constructed in an 80α prophage. All mutant phage and deletion constructs were evaluated for phage replication, SaPl1 replication, SaPl1 transduction and SaPl1 interference. One gene (ORF21) was required for 80α growth and replication, but was not required for SaPl1 growth or replication. The second gene (ORF22) was not essential for phage replication, but was required for SaPl1 replication and high frequency transduction. The product of this gene was subsequently shown to be required for SaPl1 excision.