Virulence Genes, Antimicrobial Resistance, and Genotypes of Campylobacter jejuni Isolated from Chicken Slaughterhouses in South Korea.

Campylobacter jejuni represents one of the leading causes of bacterial gastroenteritis in humans and is primarily linked to chicken meat contamination. In the present study, we analyzed the virulence and survival genes, antimicrobial resistance, and the clonal distribution of 50 C. jejuni isolates obtained from various sources in 14 chicken slaughterhouses across 8 provinces in South Korea from 2019 to 2022. Furthermore, we determined their genetic relatedness to human-derived isolates registered in PubMLST using multilocus sequence typing (MLST). All isolates harbored various virulence and survival genes (flhA, cadF, cdtA, cdtC, cmeA, and sodB) out of 17 tested genes, as confirmed via polymerase chain reaction analysis. Adherence factor gene virB11 was not detected in any isolate. All isolates harbored 12 or more virulence and survival genes. Antimicrobial susceptibility testing indicated that ciprofloxacin resistance was the most prevalent (84.0%), followed by nalidixic acid (82.0%) and tetracycline (52.0%) resistance. MLST analysis of the isolates revealed 18 sequence types (STs), including four new ones. Overlapping STs between chicken slaughterhouse and human-derived isolates included ST42, ST45, ST50, ST137, ST354, and ST464. Our study identified 11 clonal complexes (CCs), with CC-21 being the most prevalent in both human and chicken slaughterhouse-derived isolates. This study provides comprehensive insights into recent C. jejuni isolates from chicken slaughterhouses, including data on quinolone resistance and virulence factors. The MLST-based genetic relatedness between isolates from humans and chicken slaughterhouses in this study suggests the potential of C. jejuni transmission from chickens to humans through the food chain. This study suggests the need for improved management practices in chicken slaughterhouses to reduce the transmission of chicken slaughterhouse-derived C. jejuni to humans.

A Novel Curriculum for Internal Medicine Residents to Care for High-Need, High-Cost Patients.

OBJECTIVES: High-need, high-cost (HNHC) patients represent a small proportion of patients in the US, but result in disproportionately higher healthcare utilization. Teaching Internal Medicine (IM) resident trainees to provide high value care for HNHC patients is critical. We sought to improve resident attitudes and increase clinical skills associated with treating HNHC patients by creating a curriculum that leveraged the UCLA Extensivist Program, a patient-centered medical home for HNHC patients. METHODS: We developed a curriculum for PGY-2 and PGY-3 IM residents centered on caring for HNHC patients over the course of 6, 4h sessions during 1 academic year. Participants completed pre- and post-intervention surveys assessing self-rated attitudes and skills associated with caring for an HNHC patient population. RESULTS: Twenty-one IM residents completed the curriculum and 41 were in the control group. There were no statistically significant differences in assessed attitudes and skills, but there were trends of improvement, including a decrease in participants who agreed or strongly agreed they felt overwhelmed when seeing patients for posthospital discharge follow up (45.0% pre- to 41.7% post-intervention) and an increase in participants who agreed or strongly agreed they have the skills to successfully transition HNHC patients between inpatient and ambulatory settings (20.0% pre- to 33.3% post-intervention). Participants reported better understanding of resources available to HNHC patients, effective coordination of transitions of care, and comprehensive assessment of social determinants of health. CONCLUSION: A curriculum to improve resident attitudes and skills associated with caring for HNHC patients was successfully implemented in an IM program at a large academic medical center. The curriculum may be adapted for other training programs; long-term training woven throughout training may be important to significantly improve resident education on how to care for HNHC patients.

Tracking the contamination sources of microbial population and characterizing Listeria monocytogenes in a chicken slaughterhouse by using culture-dependent and -independent methods.

Listeria monocytogenes is the etiologic agent of listeriosis, a foodborne disease that poses a threat to public health globally. Chicken meat exhibits heightened susceptibility to L. monocytogenes contamination during butchery. The persistence of this pathogen in the slaughterhouse environment enables recurring contamination of meat products. This study aimed at identifying the sources and transmission routes of L. monocytogenes contamination within an abattoir where it was consistently detected for three consecutive years (2019-2021). Furthermore, the environmental factors aiding contamination along chicken processing lines were determined by surveying the microbiome within the facility. Samples collected in 2019 to 2021 were subjected to culture-dependent analysis to assess the prevalence, serotypes, and multi-locus sequence typing (MLST) of L. monocytogenes. Additionally, the specimens collected in 2021 underwent culture-independent analysis via real-time quantitative polymerase chain reaction (qPCR) and 16S rRNA gene amplicon sequencing to identify the contamination sources and characterize the entire microbial community within the slaughterhouse. L. monocytogenes was isolated only from the clean zone, where the final slaughtering stage occurs. Most strains isolated from the final carcasses showed the same genetic cluster as the isolate in the chilling water and were assigned to MLST profile ST3. Culture-independent qPCR confirmed L. monocytogenes contamination in all samples, excluding post-scalding carcasses, prewashed post-evisceration carcasses, and the bleeding areas. Consequently, qPCR enabled more comprehensive identification of L. monocytogenes contamination points than culture-dependent approaches. Moreover, 16S rRNA gene amplicon sequencing demonstrated that psychro-tolerant and spoilage-related bacteria with L. monocytogenes-like attributes exhibited enhanced viability in the clean zone and immersion-chilling water. Metagenomics-based source tracking analysis further revealed that the shackles and chilling waters represent predominant sources of cross-contamination between different slaughterhouse zones, whereas the grading and packaging workstations and chilling water in the clean zone were deemed crucial sources affecting final carcass contamination. Collectively, these findings demonstrate through culture-dependent and -independent methods that L. monocytogenes spreads along the slaughter line, contaminating the slaughterhouse. Moreover, by investigating changes in microbial community and bacterial flow along the slaughter line within the facility, the sources influencing carcass contamination can be effectively traced.

Prevalence of asymptomatic infections of Chlamydia psittaci in psittacine birds in Korea.

Avian chlamydiosis is an acute or chronic bacterial disease of birds. Chlamydia psittaci is the primary agent of the disease. It is also an important zoonotic pathogen. Chlamydia avium and Chlamydia gallinacea have also been recognized as potential causative agents of the disease. Clinical signs of this disease can vary in severity. Asymptomatic infections of Chlamydia have commonly been reported in various birds worldwide. In this study, we investigated the distribution of Chlamydia species in healthy psittacine birds in Korea. A total of 263 samples (pharyngeal/cloacal swabs and faeces) were collected from psittacine birds of 26 species in five zoos, five parrot farms and seven parrot cafes between 2020 and 2021. Ages of these birds had a wide range (1 month to 30 years). During sample collection, no bird showed any clinical signs indicating diseases such as chlamydiosis. Samples were tested for the presence of Chlamydia spp. using real-time PCR assays. Chlamydia spp. were detected in 168 (63.9%) samples and C. psittaci was detected in 96 (36.5%) samples. However, C. avium and C. gallinacea were not detected. There were no significant differences in the prevalence of asymptomatic infections in birds among three types of housing environments. Regarding ompA genotypes, 87 C. psittaci-positive samples had genotype A based on sequence analysis (n = 28) and genotype-specific real-time PCR (n = 59). Other positive samples were untyped (n = 9). Overall findings showed high prevalence of asymptomatic infections of C. psittaci in psittacine birds in Korea, posing a significant hazard to public health.

A Multiplex PCR Assay for Differential Identification of Wild-type and Vaccine Strains of Mycoplasma gallisepticum.

Mycoplasma gallisepticum (MG) can cause respiratory disease in chickens and result in serious economic losses in the chicken industry. The use of live vaccines has been a favorable option for the control of MG infection in multi-age commercial layers and broiler breeders. There are three live vaccines, including ts-11, 6/85, and F strain, that have been commonly used in various parts of the world, including South Korea. The definitive diagnosis of the infection, therefore, requires the differentiation of wild-type field strains of MG from the vaccine strains used. Thus, we aimed to develop a novel multiplex PCR assay to discriminate between vaccine strains (ts-11, 6/85, and F strain) and wild-type field strains of MG isolated from infected chickens. We designed four novel primer sets that are each specific to MG species, ts-11, 6/85, and F strain. The multiplex PCR assay using the primer sets differentially identified wild-type and vaccine strains of MG but did not detect other avian bacteria. The detection limit of this assay was 250 fg/µL of genomic DNA of each strain tested. In addition, this assay was applied to 36 MG strains isolated from chickens over the past 20 years in South Korea. As a result, the assay identified 22 wild-type strains and 14 vaccine strains. Consequently, the novel multiplex PCR assay can discriminate between vaccine and wild-type field strains of MG and could be a valuable tool for the diagnosis of MG infection in MG-vaccinated chicken flocks.

Association of GSTM1 and GSTT1 Null Genotypes with Toluene Diisocyanate-Induced Asthma.

BACKGROUND: Toluene diisocyanate (TDI) causes occupational asthma by generating oxidative stress, leading to tissue injury and inflammation. Glutathione transferases (GSTs) are detoxifying enzymes that eliminate oxidative stress. We examined whether the genotypes of the GSTM1 and GSTT1 genes are associated with TDI-induced occupational asthma (TDI-OA). METHODS: The study population consisted of 26 asthmatics with a positive response to the TDI challenge (TDI-PA) and 27 asthmatics with negative responses (TDI-NA). GSTM1 and GSTT1 null and wild-type genotypes were determined using multiplex PCR. The plasma GSTM1 and GSTT1 protein concentrations were determined using ELISA. RESULTS: The GSTM1 null genotype was more frequent in the TDI-PA than in the TDI-NA (77.8 vs. 50.0%, OR = 3.5, p=0.03), while the frequency of the GSTT1 null genotype tended to be higher in the TDI-PA than in the TDI-NA (59.3 vs. 42.3%, OR = 1.98, p=0.21). When analyzed together, the GSTM1/GSTT1 null genotype was more frequent in the TDI-PA than in the TDI-NA (48.2 vs. 15.3%, OR = 6.5, p=0.04). The decline in the FEV in 1 s after TDI challenge was higher with the GSTM1/GSTT1 null than the GSTM1 wild-type/GSTT1 null genotypes (24.29% vs. 7.47%, p=0.02). The plasma GSTM1 level was lower with the GSTM1 null than with the GSTM1 wild-type genotypes both before (13.7 vs. 16.6 ng/mg, p=0.04) and after (12.9 vs. 17.1 ng/mg, p=0.007) the TDI challenge, while the GSTT1 level was not changed with either the GSTT1 null or wild-type genotype. CONCLUSIONS: The GSTM1 null genotype, but not GSTT1 alone, may confer susceptibility to TDI-OA. However, the genetic effect of the GSTM1 null genotype may be enhanced synergistically by the GSTT1 null genotype. The genetic effect of GSTM1 was validated in the plasma as the GSTM1 protein level. Therefore, the GSTM1 and GSTT1 genotypes may be useful diagnostic markers for TDI-OA.

A multiplex real-time PCR assay for differential identification of avian Chlamydia.

Avian chlamydiosis is an acute or chronic disease of birds after infection by Chlamydia. Although Chlamydia psittaci is the primary agent of the disease, two additional species, Chlamydia avium and Chlamydia gallinacea, have also been recognized as potential disease agents. Therefore, the diagnosis of avian chlamydiosis requires differential identification of these avian Chlamydia species. The objective of the present study was to develop a multiplex real-time polymerase chain reaction (PCR) assay to rapidly differentiate between these three species of avian Chlamydia (C. psittaci, C. avium, and C. gallinacea) as well as to detect the genus Chlamydia. Specific genetic regions of the three species were identified by comparative analysis of their genome sequences. Also, the genus-specific region was selected based on 23S rRNA sequences. PCR primers and probes specific to the genus and each species were designed and integrated in the multiplex real-time PCR assay. The assay was highly efficient (94.8-100.7%). It could detect fewer than 10 copies of each target sequence of the genus and each species. Twenty-five Chlamydia control and field DNA samples were differentially identified while 20 other bacterial strains comprising 10 bacterial genera were negative in the assay. This assay allows rapid, sensitive, and specific detection of the genus and the three species of avian Chlamydia in a single protocol that is suitable for routine diagnostic purposes in avian diagnostic laboratories.

Activation of Hair Cell Growth Factors by Linoleic Acid in Malva verticillata Seed.

Hair loss by excessive stress from work and lifestyle changes has become a growing concern, particularly among young individuals. However, most drugs for alopecia impose a plethora of side effects. We have found the powerful impact of Malva verticillata seed extracts on alleviating hair loss. This study further isolated effective chemicals in M. verticillata seed extracts by liquid silica gel column chromatography. Under the screening for the growth rate (%) of human follicles dermal papilla cells (HFDPCs), we identified linoleic acid (LA) and oleic acid in n-hexane of M. verticillate (MH)2 fraction. LA treatment activated Wnt/ß-catenin signaling and induced HFDPCs growth by increasing the expression of cell cycle proteins such as cyclin D1 and cyclin-dependent kinase 2. LA treatment also increased several growth factors, such as vascular endothelial growth factor, insulin-like growth factor-1, hepatocyte growth factor, and keratinocyte growth factor, in a dose-dependent manner. Besides, LA significantly inhibited Dickkopf-related protein expression (DKK-1), a primary alopecia signaling by dihydrotestosterone. Our findings suggest that LA treatment may alleviate a testosterone-induced signaling molecule and induces HFDPCs growth by activating Wnt/ß-catenin signaling.

Comparative Characteristics and Zoonotic Potential of Avian Pathogenic Escherichia coli (APEC) Isolates from Chicken and Duck in South Korea.

Avian pathogenic Escherichia coli (APEC) causes colibacillosis, which is an economically important disease in the poultry industry worldwide. The present study investigated O-serogroups, phylogenetic groups, antimicrobial resistance, and the existence of virulence-associated genes (VAGs) and antimicrobial resistance genes in 125 APEC isolates between 2018 and 2019 in Korea. The phylogenetic group B2 isolates were confirmed for human-related sequence types (STs) through multi-locus sequence typing (MLST). O-serogroups O2 (12.5%) and O78 (10.3%) and phylogenetic group B1 (36.5%) and A (34.5%) were predominant in chicken and duck isolates, respectively. Out of 14 VAGs, iucD, iroN, hlyF, and iss were found significantly more in chicken isolates than duck isolates (p < 0.05). The resistance to ampicillin, ceftiofur, ceftriaxone, and gentamicin was higher in chicken isolates than duck isolates (p < 0.05). The multidrug resistance (MDR) rates of chicken and duck isolates were 77.1% and 65.5%, respectively. One isolate resistant to colistin (MIC 16 µg/mL) carried mcr-1. The B2-ST95 APEC isolates possessed more than 9 VAGs, and most of them were MDR (82.4%). This report is the first to compare the characteristics of APEC isolates from chickens and ducks in Korea and to demonstrate that B2-ST95 isolates circulating in Korea have zoonotic potential and pose a public health risk.

High prevalence of a gene cluster conferring resistance to streptomycin, sulfonamide, and tetracycline in Escherichia coli isolated from indigenous wild birds.

A total of 116 Escherichia coli isolates from cecal contents of 81 indigenous wild birds in Korea were tested for antimicrobial susceptibility. Seventy-one isolates from sparrows (Passer montanus) and one isolate from doves (Columba livia) were resistant to three antimicrobials, including streptomycin, sulfonamide, and tetracycline (SSuT). PCR and subsequent sequence analysis revealed the SSuT gene cluster region (approximately 13 kb) harboring genes encoding resistance to streptomycin (strA and strB), sulfonamide (sul2), and tetracycline (tetB, tetC, tetD, and tetR). In particular, tetracycline resistance genes were located on the transposon Tn10-like element. The SSuT element-harboring E. coli can be an important source of the transmission of antimicrobial resistance to other pathogenic bacteria. Therefore, strict sanitary measures in human and animal environments are necessary to prevent the spread of resistant bacteria through fecal residues of wild birds.

High prevalence and variable fitness of fluoroquinolone-resistant avian pathogenic Escherichia coli isolated from chickens in Korea.

Colibacillosis caused by avian pathogenic Escherichia coli (APEC) is the most common bacterial disease in poultry, resulting in significant economic losses. Resistance to fluoroquinolones has been found to be high in APEC worldwide, which has increased concerns about risks to human health as well as poultry production. In the present study, we determined the prevalence, genetic traits, and fitness traits of fluoroquinolone-resistant APEC isolated from chickens in Korea using a total of 286 APEC isolates collected between 2014 and 2017. The APEC isolates were highly resistant to nalidixic acid (86.0%), ampicillin (71.7%), tetracycline (69.6%), and sulfisoxazole (61.2%), and 132 (46.2%) of the isolates were resistant to both enrofloxacin and ciprofloxacin. These fluoroquinolone-resistant isolates showed eight mutation combinations including single- or double-point mutations in the gyrA, parC, or parE genes. The isolates with double mutations (codons 83 and 87) in gyrA and additional mutations in parC and parE showed high-level fluoroquinolone resistance (minimum inhibitory concentrations, 16-128 µg/ml). The isolates fell into four phylogenetic groups, and groups A (47/132, 35.6%) and B1 (47/132, 36.4%) were the most predominant. Nine isolates (6.8%) belonged to group B2 and included major lineages of extraintestinal pathogenic E. coli, sequence type (ST) 95 (n = 3) and ST69 (n = 2). The isolates varied in their virulence-associated gene content, biofilm formation, and intramacrophage survival. Overall, fluoroquinolone-resistant APEC in poultry poses a potential risk to public health and represents a highly diverse group of the resistant bacteria that varied in their genetic and fitness traits.

Impact of Dermanyssus gallinae infestation on persistent outbreaks of fowl typhoid in commercial layer chicken farms.

Although it has rapidly decreased since the early 2000s, fowl typhoid still occurs in commercial layer chickens, causing a significant economic loss in Korea. There is growing concern about the emergence of new pathogenic strains of the causative agent, Salmonella Gallinarum, which is able to overcome vaccine immunity. It has also been suspected that the poultry red mite, Dermanyssus gallinae, which is commonly found in layer chicken farms, may be an important cause of the recurrence of fowl typhoid in the farms. This study was conducted to examine changes in the virulence of recent isolates of S. Gallinarum obtained from layer farms and estimate the potential of the disease transmission of D. gallinae in the farms. Clinical and environmental samples and mites collected from layer farms affected by fowl typhoid between 2013 and 2018 were tested for S. Gallinarum. The isolates were characterized by genotypic analyses and in vitro virulence assays with chicken-derived cell lines. Vaccine protection against recent isolates was examined in the chickens. A total of 45 isolates of S. Gallinarum were collected and there was no evidence of changes in their virulence. It has also been demonstrated that the S. Gallinarum 9R vaccine strain widely used in Korea is still effective in controlling fowl typhoid if the susceptibility of birds to the disease is not increased by stress. Salmonella Gallinarum isolated from the outer and inner parts of D. gallinae, environmental dust, and dead birds of the same farm showed the same or closely related genotypes. Consequently, the present study indicated that the horizontal transmission and environmental persistence of S. Gallinarum and the increased disease susceptibility of chickens in layer farms could be mediated by D. gallinae, causing persistent outbreaks of fowl typhoid.

Application of carbon dioxide as a novel approach to eradicate poultry red mites.

Poultry red mites (PRMs), Dermanyssus gallinae, are one of the most harmful ectoparasites of laying hens. Because of their public health impact, safe, effective methods to eradicate PRMs are greatly needed. Carbon dioxide (CO2) was shown to eradicate phytophagous mites; however, there is no evidence that PRMs can be eradicated by CO2. Thus, the efficacy of CO2, applied by direct-spraying and dry ice-generated exposure, for eradicating PRMs was investigated. Both treatments eradicated > 85% of PRMs within 24 h and 100% of PRMs by 120 h of post-treatment. Therefore, these novel approaches may be useful for eradicating PRMs in clinical settings.

Genotypic divergence of Avibacterium paragallinarum isolates with different growth requirements for nicotinamide adenine dinucleotide.

In 2017, for the first time in Asia, we reported the isolation of variants of Avibacterium paragallinarum with atypical NAD dependency. The present study was conducted to characterize the genotypes of 24 isolates of Av. paragallinarum in Korea, including the four variants reported previously. Most of the typical isolates (19/20) showed a unique ERIC-PCR pattern with no ERIC-PCR patterns in common between the typical isolates and the variants. Furthermore, the variants shared no ERIC-PCR patterns among themselves. All the typical NAD-dependent isolates belonged to the same phylogenetic group based on both 16S rRNA and hagA gene sequences. The four variants were placed in several groups distinct from the typical isolates. In the 16S rRNA phylogenetic analysis, two of the variants were not closely aligned to any other Av. paragallinarum, isolate although they were clearly members of the genus Avibacterium. The other variants were clustered together with NAD atypical isolates from geographically diverse global locations. Compared with the Modesto reference strain AY498870, all the variants lacked a TTTTT stretch at positions 182-186 in the 16S rRNA gene and the same deletion was shown in most of the reported variants. The typical isolates and variants shared 97.3-98.2% and 95.2-97.2% nucleotide sequence similarity, for 16S rRNA and hagA, respectively. In addition, the similarities among variants were within 98.3-100% and 96.5-98.4% for the two genes, respectively. Our results indicate that the Av. paragallinarum variants with altered NAD growth requirements were genetically different and highly divergent from the typical NAD-dependent isolates.RESEARCH HIGHLIGHTS NAD variant Korean Av. paragallinarum isolates show genetic diversity, whereas typical Korean Av. paragallinarum isolates do not.The Korean variants were not closely aligned to all other Av. paragallinarum in the 16S rRNA phylogeny.NAD atypical isolates from geographically diverse global locations clustered together.Almost all variants, including all Korean variants of Av. paragallinarum, lack a specific fragment of the 16S rRNA gene.

Sequential Transmission of Salmonella in the Slaughtering Process of Chicken in Korea.

Salmonella is one of the most common foodborne pathogens worldwide. Salmonella infections in humans are mainly associated with consumption of poultry products contaminated with this foodborne pathogen. Therefore, strict sanitary measures are necessary to control Salmonella contamination during the slaughtering process of poultry. The objective of this study was to determine the occurrence and transmission of Salmonella at a series of steps in the slaughtering process of chicken. A total of 601 samples were collected from a series of slaughtering steps (10 sampling sites) of 26 chicken slaughterhouses throughout Korea. Salmonella was isolated from samples and its distribution was analyzed along the slaughtering process. Isolates from each sampling site were tested for susceptibility to 15 antibiotics by the broth microdilution method. They were also genotypically characterized by pulsed-field gel electrophoresis (PFGE). Salmonela was isolated from 168 out of 601 samples. Sixteen serotypes were identified while six isolates were untypable. Salmonella enterica serovars Montevideo (n = 29) and Virchow (n = 27) were the most common serotypes out of 119 nonredundant isolates. Relatively high contamination rates of Salmonella were found in shackles (75.0%), feathers near plucking machine (68.5%), and feces from crates (44.0%). Twenty-three antibiotic resistance patterns were recognized and 40 (33.6%) isolates were resistant to five or more antibiotics. The same serotypes of Salmonella were distributed along the slaughtering process of each Salmonella-positive slaughterhouse. Most of those isolates belonging to the same serotype had identical or closely related PFGE profiles. They also shared common antibiotic resistance patterns. Overall findings of this study indicated that Salmonella were sequentially transmitted through the chicken slaughtering process. PRACTICAL APPLICATION: This study provides useful information on the distribution and transmission of Salmonella serotypes through the chicken slaughtering process. Overall findings indicated the need for routine microbiological monitoring along the slaughtering process. This study also showed that on-farm control of Salmonella is needed to obtain Salmonella-free chicken carcasses.

Antibiotic Susceptibility, Genetic Diversity, and the Presence of Toxin Producing Genes in Campylobacter Isolates from Poultry.

This study examined antibiotic susceptibility, genetic diversity, and characteristics of virulence genes in Campylobacter isolates from poultry. Chicken (n = 152) and duck (n = 154) samples were collected from 18 wet markets in Korea. Campylobacter spp. isolated from the carcasses were identified by PCR. The isolated colonies were analyzed for antibiotic susceptibility to chloramphenicol, amikacin, erythromycin, tetracycline, ciprofloxacin, nalidixic acid, and enrofloxacin. The isolates were also used to analyze genetic diversity using the DiversiLabTM system and were tested for the presence of cytolethal distending toxin (cdt) genes. Campylobacter spp. were isolated from 45 poultry samples out of 306 poultry samples (14.7%) and the average levels of Campylobacter contamination were 22.0 CFU/g and 366.1 CFU/g in chicken and duck samples, respectively. Moreover, more than 90% of the isolates showed resistance to nalidixic acid and ciprofloxacin. Genetic correlation analysis showed greater than 95% similarity between 84.4% of the isolates, and three cdt genes (cdtA, cdtB, and cdtC) were present in 71.1% of Campylobacter isolates. These results indicate that Campylobacter contamination should be decreased to prevent and treat Campylobacter foodborne illness.

Kinetic Behavior of Campylobacter jejuni in Beef Tartare at Cold Temperatures and Transcriptomes Related to Its Survival.

This study was conducted to examine the kinetic behavior of Campylobacter jejuni in raw beef tartare by using mathematical models and to identify genes related to C. jejuni survival at cold temperatures. C. jejuni was inoculated onto beef tartare samples, stored at 4, 10, 15, 25, and 30°C, plated on modified charcoal-cefoperazone-deoxycholate agar, and enumerated. The survival data was fitted to the Weibull model to calculate delta (δ), which is the time required for the first 1-log reduction of the cells. The Davey model was then fitted to the δ to evaluate the effect of temperature. To evaluate the performance of the developed model, the root mean square error (RMSE) was calculated by comparing the observed data with the predicted data. The mRNA was extracted from samples stored at 4 and 30°C under aerobic and anaerobic conditions, and the expression of oxidative stress response and stress response genes was evaluated. C. jejuni survived in beef tartare longer at 4°C (δ = 657.1 ± 79.6 min) than at other temperatures (9.7 ± 11.2 to 465.7 ± 139.3°C) even under aerobic conditions. The RMSE (0.475) suggested that the developed model was appropriate to describe the kinetic behavior of C. jejuni. Quantitative real-time PCR results revealed that oxidative stress and stress response genes were related to C. jejuni survival at cold temperatures, even under aerobic conditions. These results indicate that the model will be useful for describing the kinetic behavior of C. jejuni in beef tartare and that this pathogen can survive at cold temperatures because of the expression of the sodB, katA, and clpP genes.

Quantitative Microbial Risk Assessment for Campylobacter Foodborne Illness in Raw Beef Offal Consumption in South Korea.

This study evaluated the risk of Campylobacter foodborne illness caused by the intake of raw beef offal in South Korea. The prevalence of Campylobacter spp. in raw beef offal (liver and tripe) was investigated by plating samples on modified charcoal-cefoperazone-deoxycholate agar with Preston enrichment broth. Data were collected about storage temperature and length of storage of raw beef offal, and probabilistic distributions for the data were determined, using @RISK software. Predictive models were developed to describe the fate of Campylobacter in raw beef offal, and the amount and frequency of consumption and dose-response model were surveyed. Subsequently, these data were used to estimate the risk of Campylobacter foodborne illness caused by the intake of raw beef offal. Of 80 beef offal samples, 1 (1.25%) was contaminated with Campylobacter jejuni . Predictive models were used for exposure assessment. An exponential distribution was selected to represent beef offal consumption by people who eat this occasionally, with a mean of 60.2 g and 3.6% monthly consumption frequency. Simulations using @RISK predicted that the probability of Campylobacter foodborne illness per person per month is 1.56 × 10-5 for home consumption and 1.74 × 10-5 for restaurant consumption in South Korea, which indicates the risk of Campylobacter foodborne illness by intake of raw beef offal in South Korea.

Inhibition of autophagy in peripheral blood mononuclear cells by vaginal fluid from women with a malignant adnexal mass.

Inhibition of autophagy is a characteristic of ovarian cancer. We determined whether inhibition of autophagy by vaginal fluid could provide a non-invasive test for cancer risk stratification in women presenting with an adnexal mass. Vaginal fluid supernatants from 90 women undergoing evaluation for a suspicious adnexal mass were incubated with peripheral blood mononuclear cells (PBMCs) obtained from healthy women under conditions that induce autophagy. Rapamycin, an autophagy inducer, was added to some cultures. After 48 hr the cells were collected, lysed and assayed by ELISA for intracellular p62 concentration. p62 is a cytoplasmic protein that is consumed during autophagy induction. Its concentration is inversely proportional to the extent of autophagy induction. Clinical information including pathological diagnoses was obtained after completion of laboratory studies. Mean p62 levels were 9.4 ng/ml in the 21 women with a subsequent malignant diagnosis, 4.5 ng/ml in the eight women with a borderline tumor diagnosis and 3.6 ng/ml in the 61 women with benign disease (p < 0.0001, malignant vs. others). When rapamycin was added to the vaginal fluid-PBMC co-incubation, p62 levels in samples from women with a malignant diagnosis decreased to 3.3 ng/ml, a level comparable to what was observed with the nonmalignant samples. Vaginal fluid inhibition of autophagy can differentiate between women with malignant and benign adnexal masses.