Survival capability of Campylobacter upsaliensis under environmental stresses.

OBJECTIVE: Campylobacter upsaliensis has been recognized as an emerging pathogen. However, little is known about its survival in the environment. To evaluate its survival capability, we estimated the reduction in viable counts of C. upsaliensis after aerobic exposure to starvation in phosphate-buffered saline (PBS), acidity (pH = 4.3), high osmolarity (4% NaCl), and dryness in wet pulp disks at different temperatures. Also, survival in dog feces and dog food at variable temperate was assessed. RESULTS: Campylobacter upsaliensis remained culturable under starvation for 4 days at 25 °C and for 10 weeks at 4 °C. C. upsaliensis was also recoverable after exposure to high osmolality for 9 days, dryness for 5 days, and acidity for 2 days, respectively. Similarly, C. upsaliensis survived in dog feces and dog food for several days at 25 °C and weeks at 4 °C. The survival capability of the organism was dependent on the water content, and also temperature. Notably, the tested C. upsaliensis strain was less resilient under all tested conditions than a C. jejuni strain used as a control. The findings showed that C. upsaliensis is able to survive under various environmental stresses, suggesting that it could pose a potential threat to public health.

Work-related increases in titer of Campylobacter jejuni antibody among workers at a chicken processing plant in Miyazaki prefecture, Japan, independent of individual ingestion of edible raw chicken meat.

Workers in poultry abattoirs may be frequently exposed to Campylobacter jejuni, which is a leading cause of bacterial food poisoning in Japan. The present study was conducted to measure the titers of IgG and IgA antibodies against C. jejuni among 104 female workers in a chicken processing plant in Miyazaki prefecture, Japan. Information regarding habitual ingestion of raw chicken meat and potential occupational risk factors was collected using a questionnaire. Acid extracts of four C. jejuni strains representing the genotypes most dominant in Miyazaki were used as antigens. The levels of both immunoglobulins measured by ELISA were not correlated with ingestion of edible raw chicken meat, the amount consumed in one sitting, or its frequency. Although age was correlated with antibody levels, the length of employment was not. Furthermore, the IgG and IgA levels in workers at the evisceration step were significantly higher than those at other locations in the plant. To identify the bacterial proteins recognized by the workers' IgG and IgA antibodies, Western blotting followed by LC/MS was conducted. Flagellin was identified as the common protein recognized in the sera of workers for whom ELISA demonstrated both the highest and lowest antibody levels. We concluded that the titers of IgG and IgA against C. jejuni in workers at the processing plant had been increased by occupational exposure to Campylobacter, regardless of raw chicken meat ingestion.

Transcellular penetration of Treponema phagedenis isolated from papillomatous digital dermatitis in polarized normal human epidermal keratinocytes in vitro.

Papillomatous digital dermatitis (PDD) is a polymicrobial infection causing lameness in dairy cattle. Culture-independent analysis has shown that Treponema phagedenis is present consistently and predominantly in the lesions. However, the pathogenesis of PDD, especially the tissue penetration pathway, has not been examined. In the present study, we investigated whether T. phagedenis strains isolated from PDD produce proteolytic enzyme (s) for disruption of the epithelial cell barrier and have the ability to translocate in polarized normal human epidermal keratinocytes (NHEK) in vitro. Ten strains of T. phagedenis isolated from lesions did not show proteolytic activity on modified skim milk agar, although a human strain of T. denticola used as a control showed such activity. The integrity of tight junctions was monitored by measurement of transepithelial electrical resistance (TER). The TER values after inoculation of the T. phagedenis strains examined did not change during the experimental period; however, apical to basolateral translocation of T. phagedenis was confirmed after 24 hr by microscopy and Treponema-specific PCR. We further confirmed that translocation of T. phagedenis was accelerated by co-inoculation with live T. denticola, but not with heat-killed organisms. Furthermore, tight junction ZO-1 protein was not lost intensity after inoculation with T. phagedenis and the organism was observed in NHEK cells using a florescence microscope. These results suggest that T. phagedenis strains may translocate via a transcellular route in vitro and that the invasion is accelerated by other bacteria, such as T. denticola, producing proteolytic activity.

Detection and identification of adhesins involved in adhesion of Campylobacter jejuni to chicken skin.

Campylobacter jejuni is the leading cause of bacterial food poisoning worldwide. Chickens are considered to be one of the major reservoirs of Campylobacter infection in humans due to colonization of their intestinal tract. When the chickens are slaughtered and processed, the entire skin of the carcass becomes contaminated with campylobacters. We observed that the number of C. jejuni attached to chicken skin was reduced significantly after treatment of the skin with sodium hydroxide followed by washing with PBS, implying that adhesion factors involved in binding to C. jejuni may exist on skin. Such potential binding-related proteins present in alkaline extracts of the skin surface were detected by a two-dimensional overlay assay and identified by liquid chromatography mass spectrometry (LC-MS). Chicken serum albumin (CSA) was identified as a major protein in these alkaline extracts and confirmed by ELISA to bind specifically to C. jejuni. Moreover, using the same approach, flagellar hook protein E (FlgE) and major outer membrane protein (MOMP) in C. jejuni were identified as bacterial adhesins that bound to the CSA. The ability to bind CSA was also confirmed using recombinant FlgE and MOMP of C. jejuni expressed in Escherichia coli. The present findings suggest that adhesins expressed on C. jejuni cells may bind specifically via proteins present on the skin, as well as by physical attachment.

Current Status of Campylobacter Food Poisoning in Japan.

According to the annual food poisoning statistics compiled by the Ministry of Health, Labour and Welfare (MHLW) in Japan, Campylobacter replaced Salmonella and Vibrio parahaemolyticus as the leading bacterium responsible for food poisoning in 2003. Although in 2006 the number of cases of Campylobacter food poisoning was 3,439 on the basis of the MHLW statistics, it was estimated to be 1,545,363 on the basis of active surveillance, suggesting that passive surveillance yields an incidence about 450 times lower than that revealed by active surveillance. Epidemiological investigations of Campylobacter food poisoning in Japan have shown that chicken meat and its products are the most important sources of infection, as is the case in other industrialized nations. Over the last two decades, the consumption of fresh raw chicken meat and liver has been increasing in Japan. Although the MHLW recommends that chicken meat should only be eaten after thorough cooking, it is likely to account for much of the increased incidence of human campylobacteriosis. In response to this situation, the Expert Committee on Microorganisms/Viruses, Food Safety Commission of Japan, Cabinet Office, Government of Japan (FSCJ) has revised the previous risk profile of C. jejuni/coli in chicken meat by adding new findings for 2018. Moreover, the MHLW revised the Poultry Slaughtering Business Control and Poultry Meat Inspection Act in 2014 aiming at stepwise introduction of the Hazard Analysis Critical Control Point (HACCP) system into poultry processing plants. Subsequently, the Japanese government amended the Food Sanitation Act in 2018, requiring all food business operators to implement hygiene control based on HACCP principles as a general rule. This paper reviews the current status of Campylobacter food poisoning due to consumption of chicken meat in Japan and extracts the issues underlying each step of the food supply chain in order to examine the implementation of effective measures for risk management.