Cefsulodin-irgasan-novobiocin Research Articles

Aeromonas nosocomial cluster: Investigation review of possible modes of transmission

Background:Aeromonas is a gram-negative rod known to be present in water, sewage and soil which may cause infections especially in immunocompromised hosts. Cases of Aeromonas gastroenteritis have been associated with warmer weather. In total, 3 patients with extensively drug resistant (XDR) Aeromonas were identified at our facility between August and September 2022 on 2 intensive care units (ICUs). Our infection prevention, microbiology, and facility teams investigated these cases to determine whether a common source could be the mode of transmission. Methods: To first determine whether patients’ Aeromonas specimens were related, whole-genome sequencing (WGS) of the clinical isolates from 3 patients was performed using the Illumina DNA Prep Kit and Illumina MiSeq. Sequencing analysis was performed using CLC Genomics Workbench for de novo assembly, single-nucleotide polymorphisms (SNP) calling, and tree generation, Geneious Prime for reference-based assembly, annotation, and quality assessment, KmerFinder for reference identification, and the Comprehensive Antibiotic Resistance Database for resistance gene detection via protein homology. Chart review revealed that patients occupied multiple rooms between 2 ICUs (Fig. 1). Because water is a known source of Aeromonas, facility records were reviewed for water intrusion events. This analysis identified several cases in the affected patient and surrounding rooms. Sinks and faucets from 10 rooms were swabbed followed by direct plating on blood, MacConkey agar, and Aeromonas-selective cefsulodin-Irgasan-novobiocin (CIN) agar plates. Lastly, the city temperatures before and after positive cases were reviewed to identify whether any correlation could be shown between temperature and timing of infection. Results: WGS analysis revealed that the 3 Aeromonas isolates (all identified as A. hydrophila) were not directly related (minimum distance, 934 SNPs) and harbored between 4 and 19 unique antimicrobial resistance genes, including co-occurring carbapenemases VIM-2 and KPC-3 in 1 isolate and OXA-232 in another. Of the 20 environmental samples, few gram-negative nonfermenting bacteria and no Aeromonas isolates were detected (Fig. 1). Elevated city did loosely proceed patient cases of Aeromonas, suggesting a possible role of higher temperature, which may have promoted the growth of Aeromonas during the periods of the 3 cases and thus may contribute to the nosocomial infections (Fig. 2). Conclusions: Although our investigation did not reveal a definitive cause for the Aeromonas cases, it did show the importance prompt identification and investigation can have on mitigating the spread of a cluster. Our facility has not identified any additional nosocomial cases. Monitoring water intrusion events and plans for remediation continue to be a priority.Disclosures: None

Prevalence, Biotyping, and Antimicrobial Resistance of Yersinia enterocolitica Isolated from Traditional Iranian Cheeses - Evaluation of Yersinia enterocolitica in Traditional Cheeses

The present study aimed to investigate the contamination rate of various traditional Iranian cheese samples with Yersinia enterocolitica. In total, 200 cheese samples were collected from the northeast of Iran, and 10 types of traditional cheese were evaluated, including Lighvan, Kurdish, lactic, Tape-Salam, Onsory, Turkmen (type one and two), Sistani, Baluchi, and Kormange. The samples were analyzed using pre-enrichment Peptone-Sorbitol-Bile (PSB) broth, Yersinia selective agar (Cefsulodin-Irgasan-Novobiocin (CIN))following polymerase chain reaction (PCR). Antimicrobial tests were carried out using 13 antibiotics on all the positive samples. From the cheese samples collected from Khorasan Razavi province, Kurdish cheese had the highest contamination rate (9/20; 45%), while the lowest contamination rate was observed in Lighvan and Onsory cheese. Also, the most commonly identified biotype was biotype 1A (23/38; 61%). Y. entrocolitica was mostly susceptible to ciprofloxacin, tetracycline, gentamicin, chloramphenicol, cefotaxime, and ceftazidime, while resistant to ampicillin and amoxicillin.

Incidence of Yersina enterocolitica in sheep in the south region of Iraq

Yersiniosis is a zoonotic disease which infects many animal species. A preliminary study was done to detect the incidence of Yersinia enterocolitica in sheep. One thousand and two hundred fecal samples were collected randomly from sheep in four governorates in the southern region of Iraq: Thi-Qar, Al-Muthana, Messan and Basrah, in the period from July 2016 to June-2017. Enrichment Yersinia broth at 4°C for 48 hours was used for isolation of Yersinia enterocolitica. Selective Cefsulodin Irgasan Novobiocin and non selective media were used for bacterial culture. The identification of Yersinia enterocolitica was based on colony morphology and biochemical characters, API 20E and VITEK2 compact systems were used for the same purpose also. Data were analyzed by using SAS, Version 9-1. Chi- square test was used for comparison. The total isolation rate of Y. enterocolitica was 5.16% (62). High and low rates of isolation were recorded in Al-Muthana (6. 01%) and Basrah (3.86%). Similarly a significant high isolation rate was recorded in diarrheic sheep (17.4%), moreover the infection rate increased significantly (9.5%) in the young sheep (1day to 6 month's age). Furthermore, the recovery rate of Y. enterocolitica increased significantly during the cold months (12%) as compared with temperate and hot months (spring and summer), at the same instance, non significant variation among sex difference was detected. Fever, diarrhea and mild to moderate degree of dehydration were the most common clinical manifestations observed on the infected animals. Conclusively sheep were considered a source of infection to other species including human being, and the spread of microorganism increased markedly in the cold and wet environment.

Detection of Yersinia enterocolitica in Retail Chicken Meat, Mashhad, Iran.

Poultry meat is one of the most important sources of infection of Yersinia spp. for humans. The aim of the present study was to evaluate the incidence of Yersinia enterocolitica in chicken meat by using culture method on selective medium and confirmation by PCR assay. Also, biochemical methods were used for biotyping. A total of 100 chicken thigh meat samples were collected randomly from retail outlets in Mashhad, Iran. Samples were enriched in Peptone-Sorbitol-Bile (PSB) broth and then cultured on Cefsulodin-Irgasan-Novobiocin (CIN) agar containing antibiotics supplement. The DNA was extracted from suspected colonies of Yersinia spp. and then PCR test using specific primers for 16S rRNA gene of Yersinia enterocolitica was performed. In this study, 30% of chicken meat was contaminated with Yersinia spp. by culture method and 25% of chicken meat was contaminated with Yersinia enterocolitica. Biotyping of isolated colonies showed that all of the isolates belonged to biotype 1A. Culture and detection of Yersinia spp. from food samples traditionally take 4 days. Due to high accuracy and speed of PCR assay, it is a good alternative method for microbiological techniques. In conclusion, poultry meat can act as a source of Y. enterocolitica and could be considered as a public health hazard.

Evaluation of a modified Cefsulodin-Irgasan-Novobiocin agar for isolation of Yersinia spp.

Y. enterocolitica and Y. pseudotuberculosis are important food borne pathogens. However, the presence of competitive microbiota makes the isolation of Y. enterocolitica and Y. pseudotuberculosis from naturally contaminated foods difficult. We attempted to evaluate the performance of a modified Cefsulodin-Irgasan-Novobiocin (CIN) agar in the differentiation of Y. enterocolitica from non-Yersinia species, particularly the natural intestinal microbiota. The modified CIN enabled the growth of Y. enterocolitica colonies with the same efficiency as CIN and Luria-Bertani agar. The detection limits of the modified CIN for Y. enterocolitica in culture medium (10 cfu/ml) and in artificially contaminated pork (104 cfu/ml) were also comparable to those of CIN. However, the modified CIN provided a better discrimination of Yersinia colonies from other bacteria exhibiting Yersinia-like colonies on CIN (H2S-producing Citrobacter freundii, C. braakii, Enterobacter cloacae, Aeromonas hydrophila, Providencia rettgeri, and Morganella morganii). The modified CIN exhibited a higher recovery rate of Y. enterocolitica from artificially prepared bacterial cultures and naturally contaminated samples compared with CIN. Our results thus demonstrated that the use of modified CIN may be a valuable means to increase the recovery rate of food borne Yersinia from natural samples, which are usually contaminated by multiple types of bacteria.

Detection, enumeration and characterization of Yersinia enterocolitica 4/O:3 in pig tonsils at slaughter in Northern Italy

Tonsils from 150 pigs slaughtered at 270days or older were tested for Yersinia enterocolitica with different cultural methods. Samples were collected in three different abattoirs of Northern Italy between April and November 2012 and were analysed by direct plating on cefsulodin–irgasan–novobiocin (CIN) agar and by enrichment procedures following the ISO 10273:2003 reference method. Twenty-three (15.3%) samples were positive: 22 tonsils (14.7%) were positive for human pathogenic Y. enterocolitica bio-serotype 4/O:3 and one tonsil (0.7%) for Y. enterocolitica bio-serotype 1A/7,8-8,8,19. Seventeen samples out of 23 (73.9%) were positive by direct plating method. Among the enrichment procedures, the best recovery rate (8 positives out of 23; 34.8%) was obtained by the two-day enrichment in peptone–sorbitol–bile (PSB) broth followed by plating on CIN agar plates. The two-day enrichment in PSB followed by potassium hydroxide (KOH) treatment before plating onto CIN agar gave 7 positives out of 23 (30.4%), decreasing to 3 positives (13.0%) without KOH treatment. The worst results were obtained by prolonged (five days) enrichment in PSB, with or without KOH treatment, followed by plating on CIN agar: 4.3% (1 out of 23) and 0.0% recovery rates, respectively. The mean concentration was 1.9×104CFU/g, with a minimum of 1.0×102CFU/g and a maximum of 5.8×104CFU/g, thus demonstrating that tonsils may play an important role in contamination of pluck sets, carcasses, and slaughterhouse environment.Prevalence of virulence genes among the Y. enterocolitica 4/O:3 isolates was as follows: 12/22 (54.5%) for yadA, 21/22 (95.5%) for ail, 21/22 (95.5%) for inv and 22/22 (100%) for ystA.All Y. enterocolitica 4/O:3 isolates were sensitive to amoxicillin/clavulanic acid, ciprofloxacin and ceftazidime and resistant to ampicillin and cephalotin. High proportions of 4/O:3 isolates (95%) were sensitive to cefotaxime, gentamicin, kanamicin and nalidixic acid. High levels of resistance were observed to sulphonamide compounds (91%), streptomycin (64%) and chloramphenicol (55%). Multi-resistant isolates were very common; resistance to three or more antimicrobials was observed in 91% (20/22) of 4/O:3 isolates. High level of resistance to chloramphenicol was possibly due to coresistance to tiamphenicol, which was detected in 100% of the isolates.XbaI-PFGE detected four clusters among the 22 Y. enterocolitica 4/O:3 isolates. The most represented accounted for 77% (17/22) of the isolates, the second most common was found in 14% (3/22) of the isolates and the two other profiles were observed in single isolates. The comparison with a selection of human isolates supported the role of the pig as reservoir of 4/O:3 Y. enterocolitica.

Within-batch prevalence and quantification of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis in tonsils of pigs at slaughter

Yersiniosis is a common bacterial zoonosis in Europe and healthy pigs are known to be the primary reservoir of human pathogenic Yersinia enterocolitica and Y. pseudotuberculosis. However, little information is available about the prevalence of these pathogens within pig batches at time of slaughter. The tonsils of 7047 fattening pigs, belonging to 100 farms, were aseptically collected immediately after evisceration in two Belgian slaughterhouses. The batch size varied between 70 and 930 pigs. On average, 70 pigs were sampled per batch. The tonsils were examined by direct plating on cefsulodin–irgasan–novobiocin (CIN) agar plates and the number of suspect Yersinia colonies was counted. Pathogenic Y. enterocolitica serotype O:3 were found in tonsils of 2009 pigs (28.5%), originating from 85 farms. The within-batch prevalence in positive farms ranged from 5.1 to 64.4%. The number of Y. enterocolitica in positive pigs varied between 2.01 and 5.98log10CFUg−1 tonsil, with an average of 4.00log10CFUg−1 tonsil. Y. pseudotuberculosis was found in seven farms, for which the within-batch prevalence varied from 2 to 10%. In five of these farms, both Y. enterocolitica and Y. pseudotuberculosis were simultaneously present. Human pathogenic Yersinia spp. are widespread in slaughter pig batches in Belgium as 87% of the tested batches were infected with these pathogens at the time of slaughter. The large variation of the prevalence between batches may lead to different levels of contamination of carcasses and risks for public health.

Isolation of Yersinia Enterocolitica O:9 From Cows Positive in Serological Examination of Bovine Brucellosis

Abstract The paper presents the results of bacteriological and molecular investigations on the presence of Y. enterocolitica O:9 in the head, mammary and genital lymph nodes, spleen, liver, and uterus samples originating from 58 cows slaughtered due to the positive results of serological examinations for brucellosis. All samples were cultured for Brucella and Y. enterocolitica and examined in multiplex PCR assay (mPCR), in order to identify the universal 16S rRNA Brucella sp. marker and amplify the perosamine synthetase (per) gene, specific for Y. enterocolitica O:9 only. Out of 58 examined animals, in 23 cases the presence of Y. enterocolitica was demonstrated. Typical Yersinia-suspected colonies were seen after 24-48 h incubation on Cefsulodin-Irgasan- Novobiocin (CIN) Yersinia selective solid medium. The mPCR analysis confirmed the presence of predicted amplicon of 312 bp, typical for Y. enterocolitica O:9 in 20 out of 58 lymph node samples tested and similarly, as in bacteriological examination, other samples were negative. The presence of the 16S rRNA gene of Brucella, generating the amplicon of 905 bp, was not observed in any of the samples tested.

Thermal inactivation of Yersinia enterocolitica in pork slaughter plant scald tank water

The objective of this study was to establish the time–temperature combinations required to ensure the thermal inactivation of Yersinia enterocolitica during scalding of pork carcasses. A 2 strain cocktail of Y. enterocolitica (bioserotypes 2/O:5,27 and 1A/O:6,30) was heat treated at 50, 55 and 60°C in samples of scald tank water obtained from a commercial pork slaughter plant. Samples were removed at regular intervals and surviving cells enumerated using (i) Cefsulodin–Irgasan–Novobiocin Agar (CIN) supplemented with ampicillin and arabinose and (ii) Tryptone Soya Agar (TSA), overlaid with CIN agar with ampicillin and arabinose. The data generated was used to estimate D- and z-values and the formula Dx=log−1(log D60−((t2−t1)/z)) was applied to calculate thermal death time–temperature combinations from 55 to 65°C. D50, D55 and D60-values of 45.9, 10.6 and 2.7min were calculated from the cell counts obtained on CIN agar, respectively. The corresponding D-values calculated from the TSA/CIN counts were 45.1, 11 and 2.5min, respectively. The z-value was 7.8. It was concluded that a time–temperature combination of 2.7min at 60°C is required to achieve a 1 log reduction in Y. enterocolitica in pork scald tank water. The predicted equivalent at 65°C was 0.6min. This study provides data and a model to enable pork processors to identify and apply parameters to limit the risk of carcass cross-contamination with Y. enterocolitica in pork carcass scald tanks.

Yersinia enterocolitica in sheep - a high frequency of biotype 1A

BackgroundPigs are regarded as the main reservoir for human pathogenic Yersinia enterocolitica, which is dominated by bioserotype 4/O:3. Other animals, including sheep, have occasionally been reported as carriers of pathogenic strains of Y. enterocolitica. To our knowledge, this is the first study performed in the Nordic countries in which the presence of Y. enterocolitica in sheep is investigated.MethodsTonsils and faecal samples collected from sheep slaughtered on the island Gotland (Sweden) from September 2010 through January 2011 were analysed for presence of Y. enterocolitica. In an attempt to maximize recovery, several cultural strategies were applied. Various non-selective media were used and different temperatures and durations of the enrichment were applied before subculturing on Cefsulodin Irgasan Novobiocin (CIN) agar. Presumptive Y. enterocolitica colonies were subjected to urease, API 20E and agglutination test. Yersinia enterocolitica isolates were biotyped, serotyped, and tested for pathogenicity using a TaqMan PCR directed towards the ail-gene that is associated with human pathogenic strains of Y. enterocolitica.ResultsThe samples collected from 99 sheep yielded 567 presumptive Y. enterocolitica colonies. Eighty urease positive isolates, from 35 sheep, were identified as Y. enterocolitica by API 20E. Thirty-four of 35 further subtyped Y. enterocolitica isolates, all from faecal samples, belonged to biotype 1A serotype O:5, O:6. O:13,7 and O:10. One strain was Yersinia mollaretii serotype O:62. No human pathogenic strains of Y. enterocolitica were found in the investigated sheep. Other species identified were Y. kristensenii (n = 4), Y. frederiksenii/intermedia (n = 3), Providencia rettgeri (n = 2), Serratia marcescens (n = 1) and Raoultella ornithinolytica (n = 1).ConclusionsThis study does not support the hypothesis that sheep play an important role in transmission of the known human pathogenic Y. enterocolitica in the studied geographical region. However, because there are studies indicating that some strains of Y. enterocolitica biotype 1A may cause disease in humans, the relative importance of sheep as carriers of human pathogenic strains of Y. enterocolitica remains unclear. Tonsils do not appear to be favourable sites for Y. enterocolitica biotype 1A in sheep.

Effect of Sampling and Short Isolation Methodologies on the Recovery of Human PathogenicYersinia enterocoliticafrom Pig Tonsils

The objective of this study was to determine the effect of sampling (swab samples compared to destructive samples) on isolation rates of human pathogenic Yersinia enterocolitica from pig tonsils. Moreover, the relative efficiency of different rapid, routinely applicable isolation methods was evaluated. Therefore, swab and destructive samples from tonsils of 120 pigs at slaughter were analyzed in parallel using direct plating and different enrichment methods. Salmonella-Shigella-desoxycholate-calcium chloride (SSDC) agar, cefsulodin-irgasan-novobiocin (CIN) agar, and Yersinia enterocolitica chromogenic medium (YeCM) were used as selective agar media. For enrichment, irgasan-ticarcillin-potassium chlorate (ITC) broth and peptone-sorbitol-bile (PSB) broth were incubated at 25°C for 48 h. Overall, 55 tonsils (45.8%) were positive for Y. enterocolitica bioserotype 4/O:3. Recovery was significantly higher using the destructive method compared to the swabbing method. Direct plating resulted in 47 and 28 Y. enterocolitica-positive destructive and swab samples, respectively. Alkali treatment of PSB and ITC enrichment broths significantly increased recovery of pathogenic Y. enterocolitica from destructive tonsil samples. The performance of YeCM for qualitative and quantitative isolation of pathogenic Y. enterocolitica from pig tonsils was equal to SSDC and CIN. In conclusion, direct plating and ISO 10273: 2003 with minor modifications are suitable and rapid methods for isolation of pathogenic Y. enterocolitica from destructive tonsil samples.

English

The objective of this study is to investigate the prevalence and determine the antimicrobial susceptibility pattern of Yersinia species in beef meat and chicken meat samples in different seasons. In this study 379 pieces of beef and chicken meats were examined for the presence of Yersinia species between April 2007 and March 2008. 25 g of homogenized food samples was pre-enriched in PBS then it was cultured on cefsulodin-irgasan-novobiocin (CIN) agar. Susceptibility testing of bacterial strains was performed at 28ËšC by the agar diffusion method. Yersinia spp. was isolated from 60 of 379 (15.8%) beef meat and chicken meat samples. Y. entrocolitica was found in 48 of 60 (80%) positive samples. The rate of other 3 Yersinia spp, Y. ferederiksenii, Y. intermedia, Y. kristensenii, were 7(11%), 4(6%) and1 (0.01%) out of 60 isolates, respectively. 98% of isolates were susceptible to choloramphenicol and gentamicin. The most antibiotic resistance belongs to cephalothine (98%). Our results showed that isolation ratio of Y. enterocolitica and the other species is higher in cold climates. The majority of isolates were resistant to cephalothine. The most active pharmacologic agents were chloramphenicol, gentamicin and trimetoprim.   Key words: Yersinia enterocolitica, antimicrobial susceptibility, beef meat, chicken.

Qualitative and Quantitative Detection of Human Pathogenic Yersinia enterocolitica in Different Food Matrices at Retail Level in Bavaria

Yersinia enterocolitica is a major foodborne pathogen and the third most important bacteriological cause of diarrhea in Germany. However, studies investigating the occurrence of human pathogenic Y. enterocolitica in food at the retail level are very rare. Most of the studies published so far show qualitative but not quantitative data concerning the prevalence of this human pathogen. In this study the qualitative and quantitative assessment of human pathogenic Y. enterocolitica in different food matrices was investigated. For the qualitative analysis we used an enrichment method according to the International Organisation of Standardization (ISO) standard in combination with a real-time polymerase chain reaction (PCR) method detecting the ail gene of Y. enterocolitica. After detecting Y. enterocolitica in a sample, a quantitative investigation on Cefsulodin-Irgasan-Novobiocin (CIN) Agar was done to get information about the contamination level of the different samples. During the years 2008 and 2009, 446 samples of pork and pork products, 51 samples of game meat, and 61 raw milk samples were investigated for the presence of human pathogenic Y. enterocolitica. The samples were collected at the retail level in Bavaria. From the pork samples investigated, 81 samples (18%) were positive for the ail gene by real-time PCR, but human pathogenic Y. enterocolitica O:3 were found only in 46 (10%) pork samples by culture; the concentration in the samples ranged between 0.04 cfu/g and 2.30 × 10(5) cfu/g. Three game meat samples were positive by real-time PCR, but not by the cultural detection. All raw milk samples were negative by real-time PCR and culture.

Evaluation of isolation methods for pathogenic Yersinia enterocolitica from pig intestinal content

The aim of this study was to evaluate the efficiency of four isolation methods for the detection of pathogenic Yersinia enterocolitica from pig intestinal content. The four methods comprised of 15 isolation steps using selective enrichments (irgasan-ticarcillin-potassium chlorate and modified Rappaport broth) and mildly selective enrichments at 4 or 25 degrees C. Salmonella-Shigella-desoxycholate-calcium chloride agar, cefsulodin-irgasan-novobiocin agar were used as plating media. The most sensitive method detected 78% (53/68) of the positive samples. Individual isolation steps using cold enrichment as the only enrichment or as a pre-enrichment step with further selective enrichment showed the highest sensitivities (55-66%). All isolation methods resulted in high numbers of suspected colonies not confirmed as pathogenic Y. enterocolitica. Cold enrichment should be used in the detection of pathogenic Y. enterocolitica from pig intestinal contents. In addition, more than one parallel isolation step is needed. The study shows that depending on the isolation method used for Y. enterocolitica, the detected prevalence of Y. enterocolitica in pig intestinal contents varies greatly. More selective and sensitive isolation methods need to be developed for pathogenic Y. enterocolitica.

Yersinia enterocolitica in slaughter pig tonsils: Enumeration and detection by enrichment versus direct plating culture

Tonsil samples from 139 slaughter pigs were examined for the presence of pathogenic Yersinia enterocolitica by enrichment procedures based on the standard method ISO 10273:2003. In addition, samples were tested by direct plating method to evaluate its efficiency compared to the enrichment culture methods and to quantify the level of contamination in porcine tonsils. In total, 52 samples (37.4%) were positive for pathogenic Y. enterocolitica, all belonging to bioserotype 4/O:3. Fifty out of the 52 positive samples (96.2%) were detected by direct plating. Enumeration showed an average concentration of 4.5 log 10 CFU g −1 and 4.4 log 10 CFU g −1 tonsil on Salmonella- Shigella-desoxycholate-calcium chloride (SSDC) and cefsulodin-irgasan-novobiocin (CIN) agar plates, respectively. The enrichment procedures recommended by the ISO 10273:2003 method were not optimal for the isolation of pathogenic Y. enterocolitica from pig tonsils: two days enrichment in irgasan-ticarcillin-potassium chlorate (ITC) broth resulted in an isolation rate of 84.6%, while 5 days enrichment in peptone-sorbitol-bile (PSB) broth recovered only 59.6% of positive samples. Reducing the enrichment time in PSB from 5 to 2 days resulted in a significantly higher recovery rate (94.2%) and might serve as an appropriate enrichment protocol for the isolation of pathogenic Y. enterocolitica from pig tonsils. Compared to enrichment culture methods, results based on direct plating can be obtained in a shorter time course and provide quantitative data that might be needed for further risk assessment studies.

Prevalence of Yersinia enterocolitica in Market Weight Hogs in the United States

Pigs are the major animal reservoir for Yersinia enterocolitica strains, which are potentially pathogenic for humans. The goals of this study were (i) to estimate the individual animal and on-farm prevalences of Y. enterocolitica in hogs based on tonsil samples collected during National Animal Health Monitoring System Swine 2002 study and (ii) to use these data with data previously published for fecal samples to determine on-farm risk factors for Y. enterocolitica. Tonsil swabs (1,218) and fecal samples (2,847) were collected on 124 farms located in the top 17 pork-producing states. Ten percent of tonsils (122 of 1,218 samples) were positive in irgasan-tiracillin-chlorate (ITC) enrichment broth by real-time PCR, but only 5.6% of samples (68 of 1,218) were positive after subculture on the more selective cefsulodin-irgasan-novobiocin (CIN) agar. For tonsils, the on-farm prevalence based on real-time PCR detection of the ail gene in ITC enrichment broth cultures was 32% (32 of 100 premises sampled); the prevalence based on subculture in CIN agar was 19.6% (20 of 102 premises). Results of bacteriological isolation and real-time PCR analysis of tonsils and feces were combined to estimate prevalence (individual animal and farm), which was subsequently correlated with 40 farm management practices. Four factors and their accompanying odds ratios (ORs) were identified in the final regression model: location in a central state (OR =0.3), vaccination for Escherichia coli (OR = 3.0), percentage of deaths due to scours (OR = 3.5), and presence of meat or bone meal in grower-finisher diet (OR = 4.1).

A new chromogenic agar medium for detection of potentially virulent Yersinia enterocolitica

Several outbreaks of foodborne yersiniosis have been documented and this disease continues to be source of infections transmitted through foods. The selective agars most commonly used to isolate Yersinia enterocolitica in clinical, food and environmental samples, cefsulodin–irgasan–novobiocin (CIN) and MacConkey (MAC) agars, lack the ability to differentiate potentially virulent Y. enterocolitica from other Yersinia that may be present as well as some other bacterial spp. This study proposes the use of an agar medium, Y. enterocolitica chromogenic medium (YeCM), for isolation of potentially virulent Y. enterocolitica. This agar contains cellobiose as the fermentable sugar, a chromogenic substrate and selective inhibitors for suppression of colony formation by many competing bacteria. All strains of potentially virulent Yersinia of biotypes 1B, and biotypes 2-5 formed convex, red bulls-eye colonies on YeCM that were very similar to those described for CIN agar. However, Y. enterocolitica biotype 1A and other related Yersinia formed colonies that were purple/blue on YeCM while they formed typical red bulls-eye colonies on CIN agar. When a mixture of potentially virulent Y. enterocolitica biotype 1B, Y. enterocolitica biotype 1A and 5 other bacterial species was used to artificially contaminate tofu and then spread-plated on three selective agars, Y. enterocolitica biotype 1B colonies were easily distinguished from other strains on YeCM. However, Y. enterocolitica biotype 1B colonies were indistinguishable from many other colonies on CIN and only distinguishable from those of C. freundii on MAC. When colonies were picked and identified from these agars, typical colonies from YeCM were confirmed only as Y. enterocolitica biotype 1B. Typical colonies on CIN and MAC were found to belong to several competing species and biotypes.

The prevalence of pathogenic Yersinia enterocolitica among diarrhea patients in Jos, Nigeria

One hundred and fifty (150) stool samples from diarrhoeic children and adults seeking for medical attention (including hospitalized patients) in Vom Christain Hospital (VCH), Mandela Clinic (MC) Vom and Dagott Family Health Clinic (DFHC) Vom were screened for Yersinia enterocolitica infection between August 2005 and August 2006. The isolation methods adopted were direct plating on MacConkey Agar (MCA), Deoxycholate Citrate Agar (DCA) and cold enrichment method using phosphate buffered saline prior to subculture onto selective solid culture media (Cefsulodin Irgasan Novobiocin [CIN] agar). Out of the 150 samples screened, 6 (15%) were positive. The incidence of the infection was highest among those aged 1 - 10 years 3 (7.5%), followed by 21 - 31 years 2 (5%) and 11 - 20 years 1 (2.5%). Serotyped and biotyped, pathogenic Y. enterocolitica (2/O: 9. 4/O: 9) were susceptible to ciprofloxin, floxavid, streptomycin and tetracycline.

The prevalence of pathogenic Yersinia enterocolitica among diarrhea patients in Jos, Nigeria

One hundred and fifty (150) stool samples from diarrhoeic children and adults seeking for medical attention (including hospitalized patients) in Vom Christain Hospital (VCH), Mandela Clinic (MC) Vom and Dagott Family Health Clinic (DFHC) Vom were screened for Yersinia enterocolitica infection between August 2005 and August 2006. The isolation methods adopted were direct plating on MacConkey Agar (MCA), Deoxycholate Citrate Agar (DCA) and cold enrichment method using phosphate buffered saline prior to subculture onto selective solid culture media (Cefsulodin Irgasan Novobiocin [CIN] agar). Out of the 150 samples screened, 6 (15%) were positive. The incidence of the infection was highest among those aged 1 - 10 years 3 (7.5%), followed by 21 - 31 years 2 (5%) and 11 - 20 years 1 (2.5%). Serotyped and biotyped, pathogenic Y. enterocolitica (2/O: 9. 4/O: 9) were susceptible to ciprofloxin, floxavid, streptomycin and tetracycline.

SIMULTANEOUS RECOVERY AND DETECTION OF FOUR HEAT‐INJURED FOODBORNE PATHOGENS IN GROUND BEEF AND MILK BY A FOUR‐COMPARTMENT THIN AGAR LAYER PLATE

ABSTRACT A four‐compartment thin agar layer (4‐TAL) system was developed to improve operation efficiency and recover injured foodborne pathogens simultaneously. The system consisted of a layer of nonselective agar overlaid on four different selective agars (xylose lysine desoxycholate [XLD], cefsulodin irgasan novobiocin [CIN], modified Oxford medium [MOX] and MacConkey sorbitol agar [MSA]) housed in a four‐compartment petri dish. We applied this system to simultaneously recover heat‐injured (55C, 10 min) Escherichia coli O157:H7 (MSA), Listeria monocytogenes (MOX), Salmonella Typhimurium (XLD) and Yersinia enterocolitica (CIN) from ground beef and pasteurized milk. No significant difference (P > 0.05) occurred between the single recovery unit (nonselective agar overlaid on one selective agar in a standard petri dish) and the 4‐TAL for detecting four heat‐injured pathogens in tested samples. Both TAL methods showed greater recovery of four heat‐injured pathogens than the pathogen‐specific selective media (P < 0.05). The 4‐TAL system appears to be efficient for recovery and detection of injured pathogens in food in terms of operation, material and labor costs, and space of incubation.