Effectiveness of chemical sanitizers against Campylobacter jejuni-containing biofilms

Survival of Campylobacter jejuni in mixed-culture biofilms was determined after treatment with chemical sanitizers including chlorine, quaternary ammonia, peracetic acid (PAA), and a PAA/peroctanoic acid mixture (PAA/POA). Biofilm-producing bacteria (gram-positive rods, Y1 and W1) were isolated from chicken house nipple drinkers. A meat plant isolate (Pseudomonas sp.) was also included as a biofilm producer. Two-day-old biofilms grown on polyvinyl chloride (PVC) plastic coupons in R2A broth at 12 degrees C were incubated with 10(6) CFU/ml C jejuni for 6 h to allow attachment. The coupons were then rinsed and incubated in fresh media for an additional 24 h. C. jejuni-containing biofilms were detached by vortexing with glass beads in modified brucella broth, which was then enumerated for C. jejuni on selective/differential media. The presence of biofilm enhanced (P < 0.01) the attachment and survival of C. jejuni After the 24-h incubation, only 20 CFU/cm2 of C. jejuni were recovered from the control without biofilms compared to 2,500 to 5,000 CFU/cm2 in samples with preexisting biofilms. The presence of biofilm microflora decreased (P < 0.01) the effectiveness of sanitizers against C. jejuni. Chlorine was the most effective sanitizer since it completely inactivated C. jejuni in the biofilms after treatment at 50 ppm for 45 s. C. jejuni in biofilms was susceptible to all sanitizers tested but was not completely inactivated by treatment with quaternary ammonia, PAA, or PAA/POA mixture at 50 and 200 ppm for 45 s.     

Survival of Campylobacter jejuni in biofilms isolated from chicken houses

Campylobacter jejuni is a thermophilic and microaerophilic enteric pathogen associated with poultry. Biofilms may be a source of C. jejuni in poultry house water systems since they can protect constituent microorganisms from environmental stress. In this study, the viability of C. jejuni in biofilms of gram-positive chicken house isolates (P1, Y1, and W1) and a Pseudomonas sp. was determined using a cultural method (modified brucella agar) and direct viable count (DVC). Two-day biofilms grown on polyvinyl chloride (PVC) coupons in R2A broth at 12 and 23 degrees C were incubated with C. jejuni for a 6-h attachment period. Media were then refreshed every 24 h for 7 days to allow biofilm growth. Two-day biofilms of P1, Y1, and Pseudomonas spp. enhanced attachment (P < 0.01) of C. jejuni (4.74, 4.62, and 4.78 log cells/cm2, respectively) compared to W1 and controls without preexisting biofilm (4.31 and 4.22 log cells/cm2, respectively). On day 7, isolates P1 and Y1 and Pseudomonas biofilms covered 5.4, 7.0, and 21.5% of the surface, respectively, compared to 4.9% by W1. Viable C. jejuni on the surface decreased (P < 0.05) with time, with the greatest reduction occurring on surfaces without a preexisting biofilm. The number of viable C. jejuni determined by DVC was greater than that determined by the cultural method, indicating that C. jejuni may form a viable but nonculturable state within the biofilm. Both DVC and the cultural method indicate that biofilms enhance (P < 0.01) the survival of C. jejuni during incubation at 12 and 23 degrees C over a 7-day period.     

Temperature and nutrient effects on Campylobacter jejuni attachment on multispecies biofilms on stainless steel

Campylobacterjejuni is a thermophilic microaerophilic pathogen that is commonly found in the intestinal tract of chickens. In this study, attachment of C. jejuni 1221gfp in biofilms on stainless steel was assessed at various temperatures and with reduced nutrients. Bacteria collected from a saline rinse of processed broiler chicken carcasses were used to form initial biofilms. The whole carcass rinse (WCR) biofilms were formed by incubation of the bacteria for 16 h at 13, 20, 37, and 42 degrees C on stainless steel coupons in tryptic soy broth (TSB). The resulting biofilms were stained with Hoechst 33258 stain and visualized by epifluorescence microscopy. WCR biofilms formed at 13 degrees C yielded the highest surface area coverage (47.6%), and the lowest coverage (2.1%) was attained at 42 degrees C. C. jejuni transformed to produce green fluorescent protein (gfp) was allowed to attach to the preexisting biofilms (from WCR incubated for 16 h) at each of the four temperatures, and attached cells were enumerated by visualization with an epifluorescence microscope. Attachment of C. jejuni 1221gfp did not significantly differ (P > 0.05) among the four temperatures. C. jejuni 1221gfp was cultured only from coupons with biofilms formed at 13 and 20 degrees C. For nutrient limitation experiments, WCR biofilms were allowed to grow in 10- and 50-fold diluted TSB at 20 and 37 degrees C for 48 h. The WCR biofilm surface area coverage (approximately 2%) was greater at 37 degrees C than at 20 degrees C for both TSB concentrations. C. jejuni 1221gfp was incubated with the WCR biofilm for 48 h at 20 and 37 degrees C, and attached cells were enumerated. Attachment was significantly higher (P < 0.05) only for the treatments with 1:10 TSB at 20 degrees C and 1:50 TSB at 37 degrees C. Under reduced-nutrient conditions, C. jejuni 1221gfp was cultured only from biofilms formed at 20 degrees C. Under the conditions tested, the attachment of C. jejuni 1221gfp on stainless steel and biofilms was affected by a combination of temperature and nutrient availability, but C. jejuni culturability was affected solely by temperature.     

Demonstration of a protein synthesis in starved Campylobacter jejuni cells

For many years, environmental microbiologists working on water samples, have reported differences between bacterial counts performed by culture and by microscopy. These observations have led to the demonstration of the viable but non-culturable (VNC) state in bacteria. Some hygienist specialists underlined the risk presented by pathogenic bacteria in the VNC state. The VNC state in bacteria has been studied by a number of authors, but the relation between VNC state and bacterial stress response has not been established yet, while the VNC state is generally described in responses to adverse conditions. Campylobacter jejuni enter the VNC state in response to starvation. In our study, we searched for a protein synthesis in the first hours of the cell starvation exposure. Three Campylobacter jejuni strains were suspended in filtered, sterilized, distilled water, and incubated at 4 degrees C with gentle shaking (100 rpm). After 1, 2, 3, 4 and 5 h of starvation, C. jejuni cells were removed and subjected to a heat shock (55 degrees C, 3 min) and to a conductimetric assay. Results obtained showed that a protein synthesis occurred in the onset of the starvation period, and that these improved the nutrient assimilation and enhanced the heat resistance in starved cells.     

食源性混合菌生物被膜的形成和相互作用机制

在食品加工中,食源性病原菌生物被膜的存在会引发大量食品污染等安全问题。目前,国内外学者深入研究了单一菌生物被膜,然而对混合菌生物被膜的研究较少。本文在现有的研究基础上,归纳总结了食源性混合菌生物被膜的形成规律及混合菌生物膜中菌种间的相互作用,初步探讨了群体感应在混合菌生物膜中的作用,以期为食品领域应对和破解食源性混合菌生物被膜污染问题提供思路。     

Plant-derived compounds inactivate antibiotic-resistant Campylobacter jejuni strains

Sixty-three Campylobacter jejuni isolates were screened for their resistance to the antibiotics ampicillin, cefaclor, ciprofloxacin, erythromycin, gentamycin, tetracycline, and trimethoprim-sulfamethoxazole. Based on this screen, the resistant strains D28a and H2a and the nonresistant strain A24a were selected for evaluation of their resistance and susceptibility to inactivation by cinnamaldehyde and carvacrol, the main constituents of plant-derived cinnamon and oregano oils, respectively. Different concentrations (0.05, 0.1, and 0.2% [vol/vol] in sterile phosphate-buffered saline) of cinnamaldehyde and carvacrol were added to C. jejuni cultures with initial populations of 10(4) CFU/ml. The samples were then mixed thoroughly and incubated at 37 degrees C. Viable bacterial populations were enumerated at incubation periods of 0, 30, 60, and 120 min. The results indicate that the extent of inhibition of microbial survival was related to both the nature and concentration of antimicrobials and the incubation time. Both cinnamaldehyde and carvacrol exhibited rapid antimicrobial activity against both antibiotic-resistant and non-resistant C. jejuni strains, at concentrations of approximately 0.1% and higher. The antimicrobial efficacy of cinnamaldehyde was greater than that of carvacrol. The possible significance of the results for microbiological food safety is discussed.     

Fate of Campylobacter jejuni in butter

An outbreak of Campylobacter enteritis was associated with a restaurant in Louisiana during the summer of 1995. Thirty cases were identified, and four required hospitalization. Campylobacter jejuni was isolated from the patients, and epidemiologic studies revealed illness associated with eating garlic butter served at the restaurant. Three batches of garlic butter prepared by the restaurant associated with the outbreak and a C. jejuni isolate obtained from a patient involved in the outbreak were used for studies to determine the fate of C. jejuni in garlic butter. Studies also were done to determine the efficacy of the heat treatment used by the restaurant to prepare garlic bread to kill C. jejuni. Garlic butter was inoculated with approximately 10(4) and 10(6) CFU/g of C. jejuni and held at 5 or 21 degrees C. Results revealed that the survival of C. jejuni differed greatly, depending on the presence or absence of garlic. At 5 degrees C, C. jejuni populations decreased to an undetectable level (<10 CFU/g) within 3 h for two batches and within 24 h for another batch. In contrast, C. jejuni could survive at 5 degrees C for 13 days in butter with no garlic. At 21 degrees C, C. jejuni populations decreased to an undetectable level within 5 h for two batches and to 50 CFU/g in 5 h for another batch. In contrast, C. jejuni was detected at 500 CFU/g at 28 h after inoculation but was undetectable at 3 days in butter with no garlic held at 21 degrees C. The heating procedure (135 degrees C, 4 min) used to make garlic bread by the implicated restaurant was determined not to be sufficient for killing C. jejuni, with the internal temperature of the buttered bread after heating ranging from 19 to 22 degrees C. This study revealed that C. jejuni can survive for many days in refrigerated butter, but large populations (10(3) to 10(5) CFU/g) are killed within a few hours in butter that contains garlic. Furthermore, the heat treatment used by the restaurant to melt garlic butter in making garlic bread was not adequate to kill C. jejuni.     

A charcoal- and blood-free enrichment broth for isolation and PCR detection of Campylobacter jejuni and Campylobacter coli in chicken

The microaerophilic nature of Campylobacter and its requirement of ～5% O(2) for growth have complicated its recovery from foods. The addition to the enrichment media of oxygen quenchers such as charcoal or blood could interfere with PCR for its detection. In this study, a two-step simple aerobic method for Campylobacter detection is proposed. A modification of the Tran blood-free enrichment broth (BFEB), in which charcoal was excluded from the medium (M-BFEB), was compared with the original formulation and other enrichment broths. Campylobacter jejuni and Campylobacter coli were screened by PCR directly from the enrichment media. Various levels of pure cultures of C. jejuni and C. coli combined with Escherichia coli were inoculated into Preston, Bolton, BFEB, and the modified BFEB (M-BFEB). In addition, Campylobacter was inoculated onto retail purchased chicken skin and recovery was quantified. Rates of recovery after 24 to 48 h of enrichment at 42 °C under aerobic incubation for BFEB and M-BFEB and microaerobic incubations for Preston and Bolton broths were determined. Overall, our results indicated that the most sensitive medium was Bolton's, followed by either BFEB or M-BFEB; the least sensitive was Preston's. M-BFEB was directly coupled to a PCR assay to detect Campylobacter, avoiding intermediate plating. Campylobacter was detected in the presence of up to 10(8) E. coli cells per ml. M-BFEB facilitated detection of both C. jejuni and C. coli artificially inoculated onto chicken skin samples. M-BFEB coupled to PCR is a rapid and attractive alternative for isolation and identification of C. coli and C. jejuni from poultry.     

The biofilm forming potential of bacterial species in the genus Campylobacter

The biofilm forming abilities of 16 strains representative of 14 of the 16 species comprising the genus Campylobacter were determined on glass, stainless steel, and polystyrene plastic. The formation of biofilms has been suggested as a means by which Campylobacter is able to persist within an inhospitable environment. Of the eight microaerophilic Campylobacter species, including two strains each of Campylobacter jejuni and Campylobacter fetus, only C. jejuni strain 81–176 reliably produced a visible biofilm on multiple surfaces. Alternately, all six strains of the anaerobic Campylobacter species reliably produced visible biofilms on multiple surfaces. Electron micrographs of the individual biofilms showed relatively homogeneous biofilms produced by the anaerobic strains, while the microaerophilic C. jejuni strain 81–176 produced a biofilm containing similar quantities of both the spiral and coccoid forms. This survey suggests a difference in the biofilm forming potentials and the morphologies of the bacteria comprising the biofilms between anaerobic and microaerophilic species of Campylobacter. Additionally, differences observed in the biofilm forming ability of two strains of C. jejuni suggest the need for a further investigation of the biofilm forming potential of this species using a larger number of strains.     

Potential competitive exclusion bacteria from poultry inhibitory to Campylobacter jejuni and Salmonella

The objective of this study was to isolate from chickens potential competitive exclusion bacteria (CE) that are inhibitory to Campylobacter jejuni or Salmonella, or to both, for subsequent development of a defined CE product for use in poultry. Adult chickens from family farms, commercial farms, and broiler chicken research centers were sampled to identify and select C. jejuni-free donor chickens. A challenge treatment, which included administering perorally 106 CFU C. jejuni per chicken and determining undetectable cecal shedding of campylobacters at 4 weeks, was important for identifying the best CE donor chickens. Screening of bacterial colonies obtained from nine donor chickens by using selective and nonselective media yielded 636 isolates inhibitory to six C. jejuni strains in vitro, with 194 isolates being strongly inhibitory. Of the 194 isolates, 145 were from ceca, and 117 were facultative anaerobic bacteria. One hundred forty-three isolates were inhibitory to six strains of Salmonella (including five different serotypes) in vitro. Of these, 41 were strongly inhibitory to all C. jejuni and Salmonella strains evaluated, and most were Lactobacillus salivarius. A direct overlay method, which involved directly applying soft agar on plates with discrete colonies from mucus scrapings of gastrointestinal tracts, was more effective in isolating CE than was the frequently practiced isolation method of picking and transferring discrete colonies and then overlaying them with soft agar. The best approach for obtaining bacteria highly inhibitory to Salmonella and C. jejuni from chickens was to isolate bacteria from ceca under anaerobic conditions. Free-range chickens from family farms were better donors of potential CE strongly inhibitory to both Salmonella and Campylobacter than were chickens from commercial farms and broiler chicken research centers.     

Phage inactivation of foodborne pathogens on cooked and raw meat

Phages infecting Salmonella Typhimurium PT160 and Campylobacter jejuni were added at a low or high (10 or 10(4)) multiplicity of infection (MOI) to either low or high (<100 or 10(4)cm(-2)) densities of host bacteria inoculated onto raw and cooked beef, and incubated at 5 and 24 degrees C to simulate refrigerated and room temperature storage. Counts of host bacteria were made throughout the incubation period, with phages being counted at the first and last sampling times. Host inactivation was variable and depended on the incubation conditions and food type. Significant host inactivations of the order of 2-3 log(10)cm(-2) at 5 degrees C and >5.9 log(10)cm(-2) at 24 degrees C were achieved compared to phage-free controls using the Salmonella phage under optimal conditions (high host cell density and MOI). These results alongside those already published indicate that phages may be useful in the control for foodborne pathogens.     

Biofilm Formation Characteristics of Pseudomonas lundensis Isolated from Meat

Biofilms formations of spoilage and pathogenic bacteria on food or food contact surfaces have attracted increasing attention. These events may lead to a higher risk of food spoilage and foodborne disease transmission. While Pseudomonas lundensis is one of the most important bacteria that cause spoilage in chilled meat, its capability for biofilm formation has been seldom reported. Here, we investigated biofilm formation characteristics of P. lundensis mainly by using crystal violet staining, and confocal laser scanning microscopy (CLSM). The swarming and swimming motility, biofilm formation in different temperatures (30, 10, and 4 °C) and the protease activity of the target strain were also assessed. The results showed that P. lundensis showed a typical surface‐associated motility and was quite capable of forming biofilms in different temperatures (30, 10, and 4 °C). The strain began to adhere to the contact surfaces and form biofilms early in the 4 to 6 h. The biofilms began to be formed in massive amounts after 12 h at 30 °C, and the extracellular polysaccharides increased as the biofilm structure developed. Compared with at 30 °C, more biofilms were formed at 4 and 10 °C even by a low bacterial density. The protease activity in the biofilm was significantly correlated with the biofilm formation. Moreover, the protease activity in biofilm was significantly higher than that of the corresponding planktonic cultures after cultured 12 h at 30 °C.     

Identification of Campylobacter jejuni isolates from cloacal and carcass swabs of chickens in Thailand by a 5' nuclease fluorogenic polymerase chain reaction assay

A rapid 5' nuclease fluorogenic polymerase chain reaction (PCR) assay for identifying Campylobacter jejuni was applied to Campylobacter isolates from chicken cloacal and carcass swabs collected from three chicken farms and a slaughterhouse in Thailand. The primers and the probe were based on the sequence of the gyrA gene in C jejuni. C. jejuni isolates were identified by fluorogenic PCR assay of bacterial cells directly from Campylobacter-selective agar medium. This assay allowed the identification of C. jejuni within 1 day after colonies appeared on selective media. The fluorogenic PCR assay yielded results comparable to those of the conventional test kit (kappa = 0.76) but required less time. When the two methods disagreed with regard to species identification, results were confirmed by PCR restriction fragment length polymorphism of 23S rRNA genes. In these instances, the fluorogenic PCR assay correctly identified more isolates of C. jejuni than did the conventional test kit (six of seven isolates were unidentifiable by the conventional test kit). The fluorogenic PCR assay is a rapid and specific method that outperforms the conventional test kit in the identification of C. jejuni from environmental samples.     

Compositions of maple sap microflora and collection system biofilms evaluated by scanning electron microscopy and denaturing gradient gel electrophoresis

The bacterial microflora of maple sap and biofilms in collection system tubing were studied through the use of bacterial counts, scanning electron microscopy (SEM) of surfaces and the analysis of 16S rRNA gene by denaturing gradient gel electrophoresis (DGGE). Samples were taken at five times during the 2002 and 2003 seasons in order to follow the changes in the microflora of this complex ecosystem. Bacterial counts showed the growth of bacterial populations as the season advanced. These populations were mainly composed of psychrotrophic bacteria and Pseudomonas spp. SEM results confirmed the suspected presence of biofilms on the inner surfaces of tubing samples. Bacterial colonization and biofilm formation progressively increased during the season for both lateral and main line surfaces, and biofilms were mainly composed of rod shape bacteria. The bacterial microflora profiles obtained for sap and corresponding biofilm by DGGE showed up to 12 major bands. The Shannon-Weaver index of diversity (H) calculated from DGGE bands were statistically higher for sap samples compared to biofilm. The diversity index was relatively stable or increasing for lateral line sap and biofilm samples during the season while the diversity index for sap and biofilm samples of the main line showed a decreasing profile as the season progressed. Sequence analysis of major DGGE bands revealed the predominance of bacteria from the genera Pseudomonas, Rahnella and another, unidentified genus. The results describe the composition of sap collection system microflora as well as the formation of biofilms and will be useful for further studies on factors affecting maple product quality.     

BIOFILM FORMATION BY SALMONELLA SPP. ON CANTALOUPE MELONS**

The ability of two strains of Salmonella to form biofilms on whole cantaloupe melons was investigated. Ten microliters of bacterial suspensions was spot‐inoculated onto cantaloupe melon rinds in pre‐marked areas, and the cantaloupe melons were held at either 10 or 20C. Biofilm formation was monitored using scanning electron microscopy on excised portions of the cantaloupe melon rind at 2, 24, 48, 72 and 144 h postinoculation. Micrographs indicated that biofilm formation occurred rapidly following introduction of cells (2 h at 20C) onto the cantaloupe melon rind. A fibrillar material was visible after just 2 h at 20C, and cells were embedded in extracellular polymeric material after 24 h at either temperature. These results indicate that a human pathogen is capable of forming a biofilm on plant tissue and that biofilm formation may be responsible for the increased recalcitrance of bacteria to aqueous sanitizers.     

Influence of inoculation levels and processing parameters on the survival of Campylobacter jejuni in German style fermented turkey sausages

This study investigated the influence of inoculum levels and manufacturing methods on the survival of Campylobacter (C.) jejuni in raw fermented turkey sausages. Sausages were prepared and inoculated with C. jejuni. After inoculation, these sausages were processed and ripened for 8 days. Samples were taken throughout the ripening process. The presence of C. jejuni was established bacteriologically. Additionally, lactic acid bacteria were enumerated, pH values and water activity were measured to verify the ripening process. To detect changes in genotype and verify the identity of the recovered clones, AFLP analysis was carried out on the re-isolated strains. Whereas no C. jejuni were detectable when inoculating the sausages with the lowest inoculum (0.08-0.44 log(10) cfu/g sausage emulsion), C. jejuni were detectable for 12-24h by enrichment when inoculated with approximately 2 log(10) cfu/g. After inoculation with 4 and 6 log(10) cfu/g respectively, C. jejuni were detectable without enrichment for 12-48 h and by enrichment for 144 h at the most. The greatest decrease of the C. jejuni population occurred during the first 4 h of ripening. Only a very high inoculum level allowed the survival of the organism during a fermentation process and during ripening to pose a potential risk for consumers. Lower initial Campylobacter inoculums will be eliminated during proper ripening of the sausages, if sufficient decrease in water activity and pH-value is ensured.     

Detection of Campylobacter jejuni in naturally contaminated chicken skin by melting peak analysis of amplicons in real-time PCR

Contamination of poultry by Campylobacter spp. is a significant source of human diarrheal diseases. Traditional methods currently used to detect Campylobacter in foods are time-consuming and labor-intensive. In this study, primers designed for the Campylobacter jejuni cadF gene sequence were used in a SYBR Green I real-time PCR assay as an alternative to a conventional bacteriological method for the rapid detection of C. jejuni from poultry. Twelve portions of chicken purchased from two local grocery stores and 39 portions obtained from a commercial processing plant were examined. Samples of the skin were enriched in Bolton broth at 37 degrees C for 3 h and then at 42 degrees C for 9, 21, or 45 h under microaerobic conditions. DNA was extracted from 1-ml aliquots of the enrichment cultures using 1% Triton X-100. The DNA was used as the template in a real-time polymerase chain reaction (PCR) assay. After 24 h of enrichment, C. jejuni was isolated from 13 samples and all of the positive cultures were also detected by the real-time PCR procedure. C. jejuni was detected by both methods from samples artificially contaminated with 1 or 10 CFU of C. jejuni per 10 g, after 24 h of enrichment. The real-time PCR method was found to be sensitive and specific. It significantly reduced the time required for the detection of C. jejuni in poultry following enrichment of samples.     

Enrichment media for isolation of Campylobacter jejuni from inoculated ground beef and chicken skin under normal atmosphere

The efficiency of Hunt broth containing Oxyrase was compared with the gas replacement method for detection of Campylobacter jejuni in inoculated ground beef and chicken skin. Five strains of C. jejuni were inoculated individually into samples and cultured with various media under conditions generated by either flushing with a mixture of gases or supplementing with Oxyrase. Oxyrase media added with 7% lysed blood, 2.5% charcoal, or 6% ground cooked meat were compared with examinations from chicken skin samples. Campylobacter counts from enrichments were performed at 6, 12, 20, and 28 h of incubation. From inoculated ground beef, counts at 20 h increased by 4 to 7 log CFU/ml depending on strains and initial concentration of inocula. The efficiencies of Hunt medium using gassing and those with Oxyrase added were similar (P > 0.05). Broth containing 0.15 U/ml of Oxyrase without blood effectively supported the growth of all strains (P > 0.05). From inoculated chicken skin, 20-h incubation counts increased by 3.0 to 7.5 log CFU/ml for the gassing method and by 2.7 to 7.3 log CFU/ml for supplementation with 0.6 U/ml of Oxyrase and blood. The addition of 7% lysed sheep blood provided better Campylobacter growth than supplementing with 2.5% charcoal or 6% ground cooked meat. Enrichment media incorporating with Oxyrase is a simple, convenient, and time-saving method to replace flushing with mixed gas for isolation of Campylobacter jejuni.     

The physiology of Campylobacter species and its relevance to their role as foodborne pathogens

Campylobacter jejuni and C. coli are recognised as the leading causes of bacterial foodborne diarrhoeal disease throughout the development world. While most foodborne bacterial pathogens are considered to be relatively robust organisms, as a consequence of the necessity to survive the inimical conditions imposed by food processing and preservation, Campylobacter species have uniquely fastidious growth requirements and an unusual sensitivity to environmental stress. Campylobacters also lack many of the well characterised adaptive responses that can be collated with resistance to stress in other bacteria. The aim of this review is to outline the unusual physiology of campylobacters (C. jejuni and C. coli) and to describe how this influences their role as foodborne pathogens.     

Media for the aerobic resuscitation of Campylobacter jejuni

The microaerophilic nature of Campylobacter jejuni has complicated its recovery from human and animal sources. In this study, enhancement of the growth and aerotolerance of C. jejuni ATCC 35921 in nutrient broth no. 2 (NB2) was investigated. The efficiency of recovery of C. jejuni in NB2 containing FBP (0.025% [each] ferrous sulfate, sodium metabisulfite, and sodium pyruvate), 5% laked horse blood, hemin, Oxyrase, or activated charcoal in an aerobic atmosphere was compared with that obtained under microaerophilic incubation. The shortest lag time (lamda) for cells grown aerobically was observed with NB2 supplemented with FBP, 5% laked horse blood, 0.01 g/liter of hemin, or 0.15 U/ml of Oxyrase. The efficacy of these media to resuscitate C. jejuni cells in late exponential phase, as well as cells subjected to stress induced by cold, heat, starvation, or acid, was determined in aerobic or microaerobic atmospheres. The h of cells grown aerobically in NB2 containing both FBP and blood was similar to that obtained in the same medium incubated in a microaerobic environment (P > 0.05). However, the X was longer during aerobic growth when low numbers of cells (approximately 1 log CFU/ml) in late exponential phase were used as the initial inoculum. The best recovery of stressed C. jejuni was observed in NB2 supplemented with FBP and blood and incubated aerobically. Enrichment in media incorporating FBP and 5% laked horse blood is a simple, convenient, and time-saving method to replace microaerophilic incubation methods for the resuscitation of C. jejuni.