Genetic and Phenotypic Variation of Campylobacter jejuni NCTC11168 Caused by flhA Mutation during Laboratory Passage / 生物医学与环境科学（英文）

OBJECTIVE@#Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research. In this report, two distinguished phenotypic isolates (CJ1Z, flhA mutant strain, lawn; CJ2S, flhA complemented strain, normal colony) appeared during laboratory passages for NCTC11168.@*METHODS@#Phenotypic assessments, including motility plates, transmission electron microscopy, biofilm formation assay, autoagglutination assay, and genome re-sequencing for these two isolates (CJ1Z, flhA mutant strain; CJ2S, flhA complemented strain) were carried out in this study.@*RESULTS@#Transmission electron microscopy revealed that the flagellum was lost in CJ1Z. Phenotypic assessments and genome sequencing of the two isolates were performed in this study. The capacity for biofilm formation, colony auto-agglutination, and isolate motility was reduced in the mutant CJ1Z. Comparative genomic analysis indicated a unique native nucleotide insertion in flhA (nt, 2154) that caused the I719Y and I720Y mutations and early truncation in flhA.@*CONCLUSION@#FlhA has been found to influence the expression of flagella in C. jejuni. To the best of our knowledge, this is the first study to describe the function of the C-terminal of this protein.

Caracterización de cepas de Campylobacter jejuni obtenidas desde carne de pollo y heces de aves de corral de la zona central de Chile / Characterization of Campylobacter jejuni samples coming form poultry meat and feces

Background Campylobacter jejuni is one of the main causal agents of food borne diseases. Infections with this pathogen are mainly caused by chicken meat consumption. Aim To characterize antibiotic resistance and virulence factors in C. jejuni strains obtained from chicken meat and poultry feces in Central Chile. Material and Methods The presence of C. jejuni in 30 meat and 40 feces samples from poultry was studied. From these samples, we obtained 40 strains which were characterized at the molecular level for the presence of 16 genes involved in virulence using PCR. In parallel, antibiotic resistance for ciprofloxacin, nalidixic acid, tetracycline, erythromycin, azithromycin, chloramphenicol y ampicillin was analyzed. Results Twenty and 63% of feces and chicken meat samples were positive for C. jejuni, respectively. Moreover, a high percentage of strains showed antibiotic resistance, where 27% of strains were resistant to all tested antibiotics, except for azithromycin. Finally, 10% of the strains coming from feces contained 14 out of 16 virulence genes evaluated. Only 23% of the strains did not contain any of these genes. Conclusions A high percentage of feces and chicken meat samples are contaminated with C. jejuni. Moreover, these strains show a high genetic and phenotypic diversity represented by their antibiotic resistance profiles and the presence of virulence factors.

Presencia de serotipos de Campylobacter jejuni O:19 en la cadena avícola Argentina / Campylobacter jejuni O:19 serotype in Argentine poultry meat supply chain

Las especies termotolerantes de Campylobacter han tomado gran relevancia en los últimos años debido a que son los principales agentes zoonóticos causantes de enfermedades transmitidas por alimentos. Adicionalmente, Campylobacter jejuni serotipo O:19 ha sido relacionado con el desarrollo del síndrome posdiarreico de Guillain-Barré. El objetivo de este trabajo fue determinar la proporción de cepas de C. jejuni que se corresponden con el serotipo O:19 dentro de las aisladas en diferentes etapas de 3 cadenas de producción de carne aviar en la provincia de Santa Fe. Se observó que el 18% del total de cepas de C. jejuni recuperadas (10/55) pertenecían al serotipo O:19; estas se aislaron en 4 de las 5 etapas de producción de carne aviar elegidas a los fines de este estudio. Este hallazgo da cuenta de un riesgo importante para la salud pública de los consumidores y debería ser considerado en los estudios epidemiológicos de Campylobacter, para implementar en forma urgente medidas de control sobre este microorganismo.

Thermotolerant species of Campylobacter have been focus of attention in the last years because they are the major agent causing zoonotic foodborne diseases. In addition, Campylobacter jejuni O:19 serotype was associated with Guillain Barré syndrome. The aim of this study was to determine the proportion of C. jejuni O:19 serotype isolated at different stages of three poultry meat supply chain in Santa Fe, Argentina. The analysis showed that 18% of isolated C. jejuni belong to serotype O:19. It was also determined that the presence of these strains is given in almost all production stages. These results reflect a significant risk to public health of consumers. Epidemiological studies of Campylobacter should be considered to establish a risk manager policy.

Prevalence of virulence genes in strains of Campylobacter jejuni isolated from human, bovine and broiler

Campylobacter jejuni isolates of different origins (bovine, broiler meat, human) were screened by polymerase chain reaction for the presence of 4 genes cdtB, cst-II, ggt, and virB11, previously linked to virulence such as adherence, invasion, colonization, molecular mimicry, and cytotoxin production. In addition, the isolates were screened for the presence of the global gene regulator csrA linked to oxidative stress responses, biofilms formation, and cell adhesion. All the C. jejuni isolates were positive for cdtB gene. The csrA gene was detected in 100% and 92% of C. jejuni isolates from human and animal origin and the virB11 gene was detected in 7.3% and 3.6% isolates from chicken and human respectively. All isolates from bovine were negative for the virB11 gene. The isolates showed a wide variation for the presence of the remaining genes. Of the C. jejuni recovered from human 83.6%, and 32.7% were positive for cst-II, and ggt respectively. Out of the isolates from chicken 40% and 5.5% isolates revealed the presence of cst-II, and ggt, respectively. Finally of the C. jejuni isolates from bovine, 97.7% and 22.7% were positive for cst-II, and ggt respectively. We conclude that the genes of this study circulate among humans and animals. These results led us to hypothesize that the isolates associated with enteritis (cdtB positives) are not selected by environmental or host-specific factors. On the other hand, the high frequencies of csrA gene in C. jejuni show that this gene is important for the survival of C. jejuni in animals and humans.

Detection of CDT toxin genes in Campylobacter spp. strains isolated from broiler carcasses and vegetables in São Paulo, Brazil

Campylobacteriosis is a worldwide distributed zoonosis. One of the main virulence factors related to Campylobacter spp. in animals and humans is the cytolethal distending toxin (CDT), encoded by three adjacent genes (cdtA, cdtB, cdtC). The occurrence of Campylobacter spp. in samples of vegetables has not been reported in Brazil yet, and has seldom been described in the international literature. The detection of CDT in these strains has not been reported, either. The objectives of the present study were to determine the occurrence of Campylobacter spp. strains carrying virulence factors in samples of poultry and vegetables (lettuce and spinach) from different points of sale, thus verifying if vegetables are as an important vehicle for potentially virulent Campylobacter spp. strains as poultry. Twenty four strains were identified as Campylobacter jejuni by phenotypic and genotypic methods: 22 from broiler carcasses and two from lettuce samples. Three strains were identified as Campylobacter coli: two from broiler carcasses and one from lettuce. The presence of the cdt genes were detected in 20/24 (83.3%) C. jejuni strains, and 3/3 (100%) C. coli strains. The isolation of Campylobacter spp. strains with the cdt gene cluster in lettuce samples points to a new possible source of contamination, which could have an impact in the vegetable production chain and risk to public health. Results show that potentially virulent C. jejuni and C. coli strains remain viable in samples of broiler carcasses and vegetables at the points of sale.

Análisis molecular de la resistencia a fluoroquinolonas y macrólidos en aislados de Campylobacter jejuni de humanos, bovinos y carne de ave / Molecular analysis of fluoroquinolones and macrolides resistance in Campylobacter jejuni isolates from humans, bovine and chicken meat

Background: Campylobacter sp.- one of the leading causes of bacterial food-borne gastrointestinal illness worldwide- is increasingly resistant to fluoroquinolone and macrolide antimicrobials, which has become a major concern for public health. Objective: To describe the susceptibility patterns of Campylobacter jejuni strains to erythromycin and ciprofloxacin and to explore the origin of its resistance in human isolates. Material and Method: In this study, fifty-five ciprofloxacin and erythromycin susceptibility patterns of C. jejuni strains isolated from humans with diarrheal disease, performed by broth microdilution MIC, were compared with 55 and 44 isolates from chicken meat and bovines respectively, obtained from the Metropolitan Region, Chile. Results: Of the 55 human isolates of C. jejuni, 33 (60%) were resistant to ciprofloxacin and all were sensitive to erythromycin. Of the 55 isolates from chicken meat, 32 (58.2%) were resistant to ciprofloxacin and 1.8% were resistant to erythromycin. Of the 44 isolates of C. jejuni from cattle, 8 (18.2%) were resistant to ciprofloxacin and all were sensitive to erythromycin. Four PFGE patterns matched with certain resistance profiles and grouped isolates from human and animal. Conclusion: The findings showed continued effectiveness of erythromycin for campylobacteriosis and a high percentage of C. jejuni strains ciprofloxacin-resistant. This is interesting because it is considered that the presence of ciprofloxacin resistant strains in broiler meat can be in part the source of resistance to this antimicrobial in humans.

Introducción: El incremento de la resistencia en Campylobacter sp. (una de las principales causas de gastroenteritis bacteriana de origen alimentario) a fluoro-quinolonas y macrólidos, es un problema en salud pública. Objetivo: Conocer los patrones de susceptibilidad in vitro de Campylobacter jejuni a eritromicina y ciprofloxacina y conocer el origen de su resistencia en aislados de humanos. Material y Método: En este estudio, se compararon las susceptibilidades a ciprofloxacina y eritromicina -CIM efectuadas por microdilución en caldo- de 55 aislados de C. jejuni provenientes de humanos con enterocolitis, con 55 aislados de carne de pollo y 44 de bovinos obtenidos en la Región Metropolitana, Chile. Resultados: De 55 aislados de C. jejuni de humanos, 33(60%) presentaron resistencia a ciprofloxacina y todos presentaron susceptibilidad a eritromicina. De 55 aislados procedentes de carne de pollo, 32 (58,2%) presentaron resistencia a ciprofloxacina y un aislado resultó resistente a eritromicina (1,8%). De 44 aislados de bovinos, 8(18,2%) presentaron resistencia a ciprofloxacina y todos resultaron sensibles a eritromicina. Cuatro patrones de electroforesis a campo pulsado coincidieron en sus perfiles de resistencia y agruparon aislados de origen humano y animal. Conclusiones: Los resultados muestran que eritromicina continúa siendo efectiva para el tratamiento de la campilobacteriosis y que existe un alto porcentaje de cepas resistentes a ciprofloxacina. Se considera probable que la presencia de cepas resistentes a ciprofloxacina en la carne de pollo puede ser en parte el origen de la resistencia a este fármaco en humanos.

Genotipificación y resistencia antibacteriana de cepas de Campylobacter spp aisladas en niños y en aves de corral / Genotyping and antibacterial resistance of Campylobacter spp strains isolated in children and in free range poultry

Poultry is a main reservoir and source of human infection in campylobacteriosis. Three hundred and forty one stool samples (291 human, 50 avian) were analyzed. In the human group, 220 samples were collected from children with acute diarrheal disease (183 inpatients, 37 outpatients) and 71 from healthy children. Erythromycin and ciprofloxacin agar dilution MIC tests, Penner serotyping and RAPD-PCR genotyping were performed on 23 strains isolated. C. jejuni was reported only in patients with acute diarrhea (5.4 percent inpatients, 2.2 percent outpatients). Campylobacter prevalence in poultry was 34 percent. Cross-resistance to nalidixic acid and ciprofloxacin was found in 33.3 percent of human samples and 11.8 percent of animal samples. Human samples could not be typed using the Penner method. F serotype was the most expressed in poultry. We obtained a total of 14 genotypes (4 / 5 human and 10/15 avian). In conclusion, the predominant species in poultry and humans was C. jejuni, a significant amount of quinolone-resistant human and avian samples were obtained, and avian genotypes and serotypes were not found in human samples. The latter would mean that another source of infection could exist; therefore other reservoirs must be studied.

Las aves de consumo constituyen uno de los principales reservorios y fuente de infección humana de la campilo-bacteriosis. Se analizaron 341 muestras de deposiciones, 291 humanas y 50 aviares. De las muestras, 220 de niños con síndrome diarreico agudo-SDA (183 hospitalizados y 37 consultantes ambulatorios) y 71 niños sanos. A las 23 cepas obtenidas se les realizó CIM por dilución en agar a eritromicina y ciprofloxacina, serotipificación de Penner y genotipiicación por RAPD-PCR. Se encontró Campylobacterjejuni sólo en pacientes con SDA, de ellos 5,4 por ciento ambulatorios y 2,2 por ciento hospitalizados. En aves, la prevalencia de Campylobacter spp., fue de 34 por ciento. Hubo resistencia cruzada a ácido nalidixico y ciprofloxacina en 33,3 por ciento cepas de origen humano y 11,8 por ciento animal. Las cepas humanas fueron no tipiicables por el método de Penner. Predominó entre las aves el serotipo F. Se obtuvo un total de 14 genotipos (4/5 humanos y 10/15 aviares). En conclusión, la especie predominante en aves de corral y en humanos fue C. jejuni, existiendo una alta prevalencia de cepas de origen humano y aviar resistentes a quinolonas. Los genotipos y serotipos aviares no fueron encontrados en cepas de origen humano, lo que indica que podría existir otra fuente de infección, por lo que se requiere estudiar otros reservorios.

Cepas de Campylobacter jejuni resistentes a quinolonas aisladas de humanos, gallinas y pollos / Quinolone resistant Campylobacter jejuni strains isolated from humans and from poultry

Se compararon 8 aislamientos de Campylobacter jejuni provenientes de humanos con enfermedad diarreica aguda, con 23 aislamientos de cloaca de gallinas y pollos obtenidos de zonas próximas a la ciudad de Rosario, todos resistentes a la ciprofloxacina. Las muestras se sembraron en agar selectivo y se incubaron en microaerofilia a 42 °C. Las colonias se identificaron con el método tradicional. Los aislamientos se conservaron a -70 °C en caldo cerebro corazón con 17% v/v de glicerina. La clonalidad se determinó por RAPD-PCR, utilizando el primer 1254 (Stern NJ). Se interpretaron los aislamientos como clones distintos cuando diferían en una banda de amplificación. Se obtuvieron 5 clones diferentes. Los patrones I, II y V fueron aislados en criaderos industriales de pollos y en humanos (el II también en un establecimiento de gallinas ponedoras de huevos). En un gallinero familiar se obtuvo el patrón I. El patrón III sólo se obtuvo de humanos. El patrón IV se halló en uno de los criaderos pero no en humanos. Se pudo determinar que 93.5% de las cepas se aislaron tanto de animales como de humanos, por lo que se considera posible que la colonización de criaderos con cepas resistentes a los antimicrobianos pudiera ser el origen de la infección de humanos.

Eight quinolone resistant Campylobacter jejuni strains isolated from humans with diarrheal disease were compared with 23 isolates from chicken and from laying hens. Samples were cultured on selective agar in microaerophilia, identified by conventional tests, and conserved in 17% glycerol at -70 °C. Clones were determined by RAPD-PCR employing the 1254 primer (Stern NJ). Five patterns were obtained. Patterns I, II, and V were found in both poultry and human isolates. Pattern I was obtained from poultry in a domestic henhouse. Pattern III was only obtained from humans whereas pattern IV was only obtained from poultry. A 95.3% of clones were found in both, humans and poultry. According to these results colonization by quinolone resistant strains could be the origin of this human infection, acquired by ingestion.

Comparative analysis of cultural isolation and PCR based assay for detection of Campylobacter jejuni in food and faecal samples

In the present study, the efficacy of polymerase chain reaction (PCR) based on mapA gene of C. jejuni was tested for detection of Campylobacter jejuni in naturally infected as well as spiked faecal and food samples of human and animal origin. Simultaneously, all the samples were subjected to the cultural isolation of organism and biochemical characterization. The positive samples resulted in the amplification of a DNA fragment of size ~589 bp in PCR assay whereas the absence of such amplicon in DNA extracted from E. coli, Listeria, Salmonella and Staphylococcus confirmed the specificity of the primers. Of randomly collected 143 faecal samples comprising human diarrheic stools (43), cattle diarrheic faeces (48) and poultry faecal swabs (52) only 4, 3 and 8, respectively, could be detected by isolation whereas 6, 3 and 10, respectively, were found positive by PCR. However, among food samples viz. beef (30), milk (35), cheese (30), only one beef sample was detected both by culture as well as PCR. Additionally, PCR was found to be more sensitive for C. jejuni detection in spiked faecal and food samples (96.1 percent each) as relative to culture isolation which could detect the organism in 86.7 percent and 80 percent samples, respectively. The results depicted the superior efficacy of PCR for rapid screening of samples owing to its high sensitivity, specificity and automation potential.

Cell cycle arrest & apoptosis of epithelial cell line by cytolethal distending toxin positive Campylobacter jejuni.

Background & objectives: Campylobacter jejuni is the leading cause of gastroenteritis worldwide; cytolethal distending toxin (CDT) being an important virulence determinant. As its role in pathogenesis remains unclear, this study aims to investigate cell cycle arrest and apoptosis by CDT (+ve) and CDT (-ve) C. jejuni isolates on HeLa cells. Methods: Culture supernatants and lysates from 10 C. jejuni isolates [CDT (+ve) and CDT (-ve), five each] were incubated with HeLa cells. CDT activity on HeLa cells was confirmed by cell distension, cell cycle arrest by flowcytometry, and apoptosis by DNA fragmentation and flowcytometry. Results: Culture supernatant and lysate of only CDT (+ve) C. jejuni isolates produced cell distension. For CDT (+ve) and CDT (-ve) isolates, the cells at G2/M phase after 24, 48 and 72 h were 25.8 ± 3.79 per cent and 11.2 ± 0.58 per cent, 72.9 ± 2.44 and 14.3 ± 1.88 per cent, 93.5 ± 0.54 per cnet and 18.0 ± 1.80 per cent respectively (P<0.001). All CDT (+ve) isolates induced DNA fragmentation. Apoptosis induced by CDT (+ve) C. jejuni was significantly greater than CDT (-ve) (26.3 ± 3.49 % vs. 10.4 ± 1.01% at 24 h, 43.9 ± 2.40% vs. 17.6 ± 0.88% at 48 h, 68.4 ± 1.61% vs. 28.4 ± 1.62% at 72 h); (P<0.001). Interpretation & conclusion: The present study shows that CDT (+ve) C. jejuni contributes to the pathogenesis through epithelial cell G2/M phase arrest and apoptosis.

Survey of chicken abattoir for the presence of Campylobacter jejuni and Campylobacter coli

The genus Campylobacter is of great importance to public health because it includes several species that may cause diarrhea. These species may be found in water, food and in the intestinal tract of chickens. This study investigated the presence of Campylobacter jejuni and Campylobacter coli in chicken abattoirs in São Paulo State, Brazil. A total of 288 samples of feces, feathers, scald water, evisceration water, chiller water, and the rinse water of eviscerated, not eviscerated and chilled carcasses were collected in six chicken abattoirs. Polymerase Chain Reaction (PCR) was performed in Campylobacter spp.-positive isolates using the gene HIP, specific for hippuricase enzyme from Campylobacter jejuni and aspartokinase gene, specific to detect Campylobacter coli. The percentage of positive isolates of Campylobacter jejuni was 4.9 percent (14/288). Isolation was greater in feces samples (22 percent, 8/36). One sample was positive for the species C. coli. In conclusion, the results indicate that it is necessary to improve quality control for Campylobacter spp. in chicken abattoirs.

O gênero Campylobacter tem grande destaque em saúde pública, principalmente por pertencerem a este gênero várias espécies que podem causar diarréia. Estas espécies podem ser encontradas em amostras de água, alimentos e no trato intestinal das aves. Este estudo investigou a presença de Campylobacter jejuni e Campylobacter coli em abatedouros de aves no Estado de São Paulo. As 288 amostras foram coletadas em seis estabelecimentos e incluíram: fezes; penas; água de escaldamento, de evisceração e de resfriamento; e água de enxaguadura de carcaça não eviscerada, eviscerada e resfriada. Após o isolamento microbiológico das amostras positivas de Campylobacter spp. foi realizada uma Reação em Cadeia da Polimerase (PCR) utilizando o gene HIP, da hipuricase, específico para Campylobacter jejuni e o gene da enzima aspartoquinase, específico para Campylobacter coli. A porcentagem de amostras positivas para Campylobacter spp. foi de 4,9 por cento (14/288), sendo que o isolamento foi maior em amostras de fezes (22 por cento, 8/36). Foi isolada uma amostra positiva para C. coli. Em conclusão, os resultados indicam que há uma necessidade de melhorar a qualidade higiênico-sanitária do controle de Campylobacter em abatedouros de aves.

Ab initio gene identification: prokaryote genome annotation with GeneScan and GLIMMER.

We compare the annotation of three complete genomes using the ab initio methods of gene identification GeneScan and GLIMMER. The annotation given in GenBank, the standard against which these are compared, has been made using GeneMark. We find a number of novel genes which are predicted by both methods used here, as well as a number of genes that are predicted by GeneMark, but are not identified by either of the nonconsensus methods that we have used. The three organisms studied here are all prokaryotic species with fairly compact genomes. The Fourier measure forms the basis for an efficient non-consensus method for gene prediction, and the algorithm GeneScan exploits this measure. We have bench-marked this program as well as GLIMMER using 3 complete prokaryotic genomes. An effort has also been made to study the limitations of these techniques for complete genome analysis. GeneScan and GLIMMER are of comparable accuracy insofar as gene-identification is concerned, with sensitivities and specificities typically greater than 0.9. The number of false predictions (both positive and negative) is higher for GeneScan as compared to GLIMMER, but in a significant number of cases, similar results are provided by the two techniques. This suggests that there could be some as-yet unidentified additional genes in these three genomes, and also that some of the putative identifications made hitherto might require re-evaluation. All these cases are discussed in detail.