Susceptibility of Clostridium perfringens strains from broiler chickens to antibiotics and anticoccidials

Clostridium perfringens strains isolated in 2002 from the intestines of broiler chickens from 31 different farms located in Belgium were tested for susceptibility to 12 antibiotics used for therapy, growth promotion or prevention of coccidiosis. All strains were uniformly sensitive to the ionophore antibiotics monensin, lasalocid, salinomycin, maduramycin and narasin. All were sensitive to avilamycin, tylosin and amoxicillin, while flavomycin (bambermycin) showed low or no activity. Chlortetracycline and oxytetracycline were active at very low concentrations, but low-level acquired resistance was detected in 66% of the strains investigated. Fifty percent of these strains carried the tetP(B) resistance gene, while the tet(Q) gene was detected in only one strain. One strain with high-level resistance against tetracyclines carried the tet(M) gene. Sixty-three percent of the strains showed low-level resistance to lincomycin. The lnu(A) and lnu(B) genes were each only found in one strain. Compared with a similar investigation carried out in 1980, an increase was seen in resistance percentages with lincomycin (63% against 49%) and a slight decrease with tetracycline (66% against 74%).     

Ornithobacterium rhinotracheale: A review

Ornithobacterium rhinotracheale is a relatively recently discovered bacterium of the rRNA superfamily V. It is of worldwide distribution in commercial poultry, in which it is associated with respiratory diseases, and it is also found in wild birds. Airsacculitis and pneumonia are the most common features of infection with O. rhinotracheale. These signs can be induced by aerosol in intra-tracheal or intra-thoracic administration of the organism, and can be aggravated by other factors, such as respiratory viruses, bacteria or climatic conditions. Osteitis, meningitis and joint-infections, which can be induced by intravenous application, have been associated with O. rhinotracheale, but it remains uncertain whether the organism should be regarded as a primary pathogen. The infection can be transmitted horizontally by aerosol, as well as vertically through eggs, which probably accounts for its rapid and worldwide spread. Although O. rhinotracheale is difficult to identify, some commercial identification systems have been found to be suitable, although the media used in such systems will not always support its growth. A PCR assay was also found to be suitable for identification purposes. Twelve serotypes can be distinguished within the species O. rhinotracheale, of which serotype A is the most prevalent. Genetic investigation has revealed that more species or subspecies probably exist within the genus Ornithobacterium. Therapeutic treatment of the disease can be difficult because acquired resistance against the regular antibiotics is very common within the genus. Vaccination with autogenous inactivated vaccines has been successful in reducing clinical signs, but success depends on the adjuvant used. Only potent oil adjuvants are effective in young birds with maternal antibodies, but the use of these adjuvants is known to induce some local reactions. Live vaccination is feasible, but up to now, no avirulent strains of O. rhinotracheale have been found. Vaccination of broiler breeders induced protection against experimental infection of the progeny to at least 3 weeks of age.     

Adherence of Ornithobacterium rhinotracheale to chicken embryo lung cells as a pathogenic mechanism

Ornithobacterium rhinotracheale is a bacterium that causes respiratory disease in birds and it has been isolated in countries with a large poultry production, including Mexico. The pathogenicity mechanisms of this bacterium have not been completely elucidated yet. The capacity of the bacterium to adhere to epithelial cells of chicken in vitro has been evidenced, and since this bacterium has been isolated from the lungs and air sacs of several avian species, the aim of this study was to determine if this bacterium can adhere to chicken lung cells. We used five O. rhinotracheale reference serovars (A–E) that were in contact with primary lung cells cultured from a 19-day-old chicken embryo. O. rhinotracheale adherence was evaluated through optical and transmission electron microscopies. The results revealed that O. rhinotracheale is capable of adhering to chicken embryo lung cells within 3?h of incubation with a diffuse adherence pattern. The adherence percentages of the chicken embryo lung cells were 51–96% according to the serovar of the bacterium. Relative adherence was from 4 to 8 bacteria per cell. Transmission electron microscope data revealed intracellular bacteria inside a vacuole in less than 3?h of incubation.     

Characterization of Ornithobacterium rhinotracheale field isolates from Hungary

Ornithobacterium rhinotracheale is a widely distributed rod-shaped Gram-negative bacterium that infects several avian species including chickens and turkeys. It is associated with respiratory signs, growth retardation, mortality, and reduced egg production, thus causing severe economic losses to the poultry industries. In this study, 37 field isolates of O. rhinotracheale, collected from various locations in Hungary between 1997 and 2015, were identified and characterized by the analysis of partial 16S rRNA gene sequences, enterobacterial repetitive intergenic consensus (ERIC)-PCR, and random amplified polymorphic DNA (RAPD) PCR assays with the OPG11, OPH19, and M13 primers. Most of the field isolates were serotype A, one was serotype B, and four were serotype D. One isolate could not be typed with antisera against serotypes A–E. In a phylogenetic analysis of the 16S rRNA sequences, the isolates formed two clusters. Thirteen distinct patterns were identified with ERIC-PCR, and the RAPD assay with the M13 primer assigned the isolates to 10 different patterns. The other two RAPD assays were unsuitable for distinguishing and grouping the isolates. Neither ERIC type nor RAPD pattern correlated with the place or year of isolation. However, the strains isolated from chickens were more heterogeneous on ERIC-PCR than the isolates recovered from turkeys. In this study, ERIC-PCR was the most discriminatory method for investigating the genetic diversity of O. rhinotracheale isolates.     

Epidemiological and pathological investigation of fowl aviadenovirus serotypes 8b and 11 isolated from chickens with inclusion body hepatitis in Spain (2011–2013)

Inclusion body hepatitis caused by different fowl aviadenovirus (FAdV) serotypes has been described in several countries in recent years. In Spain, from the spring of 2011 to 2013, an increased number of outbreaks in broiler and broiler breeder flocks from different regions occurred. The objectives of the present work were to carry out the molecular characterization of FAdV strains from Spanish inclusion body hepatitis cases and to study the pathogenicity and viral dynamics of these strains in specific pathogen-free (SPF) chickens. A total of 52 inclusion body hepatitis clinical cases, including 45 from broiler farms and seven from broiler breeder farms, were analysed by conventional polymerase chain reaction and sequencing targeting the FAdV hexon gene. From these, 37 strains were classified as FAdV type 8b, while the remaining 15 were classified as FAdV types 11 (n?=?10), 2 (n?=?4) and 8a (n?=?1). In addition, two different FAdVs belonging to the genotypes 8b and 11 were used for experimental infection. Specific pathogen-free five-day-old birds were inoculated intramuscularly with a high (10^6.5 tissue culture infective dose (TCID)₅₀/ml) or low (10⁴ TCID₅₀/ml) dose of the above-mentioned FAdVs. No mortality was observed in any of the experimental groups, and only one bird showed evident clinical signs. However, macroscopic and microscopic hepatic lesions, as well as viral DNA, were detected in birds from all infection groups. Inclusion bodies and viral DNA were also detected in the pancreas and in the small and the large intestine in some birds. Long-lasting shedding and transmission to contact birds were confirmed in all infected groups.     

Efficacy of gamithromycin against Ornithobacterium rhinotracheale in turkey poults pre-infected with avian metapneumovirus

Ornithobacterium rhinotracheale is an avian respiratory pathogen that affects turkeys. The objective of this study was to evaluate the clinical efficacy of gamithromycin (GAM) against O. rhinotracheale in turkeys. The birds were inoculated oculonasally with 10⁸ colony-forming units (cfu) of O. rhinotracheale, preceded by infection with avian metapneumovirus. In addition to a negative (CONTR?) and a positive control group (CONTR+) there were two treated groups administered GAM (6?mg/kg) either subcutaneously (GAM SC) or orally (GAM PO) by administration as a single bolus at one-day post-bacterial infection (p.b.i.). From the start of the avian metapneumovirus infection until the end of the experiment, the turkeys were examined clinically and scored daily. In addition, tracheal swabs were collected at several days p.b.i. Necropsy was performed at 4, 8 and 12 days p.b.i. to evaluate the presence of gross lesions, and to collect trachea and lung tissue samples and air sac swabs for O. rhinotracheale quantification. The clinical score of the GAM SC group showed slightly lower values and birds recovered earlier than those in the GAM PO and CONTR+ groups. O. rhinotracheale cfus were significantly reduced in tracheal swabs of the SC group between 2 and 4 days p.b.i. At necropsy, CONTR+ showed higher O. rhinotracheale cfu in lung tissues compared to the treated groups. Moreover, at 8 days p.b.i. only the lung samples of CONTR+ were positive. In conclusion, the efficacy of GAM against O. rhinotracheale was demonstrated, especially in the lung tissue. However, the PO bolus administration of the commercially available product was not as efficacious as the SC bolus.     

Monoclonal antibodies for the detection of Rhizomonas Suberifaciens causal agent of corky root of lettuce,with enzyme immunoassays

Monoclonal antibodies (MAbs) were produced to Rhizomonas suberifaciens strain CA1. Initial screening of MAbs was performed with strains CA1 and FL1 of R. suberifaciens and 82 strains of other genera in antibody capture indirect enzyme‐linked immunosorbent assay (ELISA) tests. One MAb (MAb‐Rs 1) reacted with both strains of R. suberifaciens and another (MAb‐Rs 2) only with R. suberifaciens strain CA1. Both MAbs were further screened for cross‐reactivity with 28 strains of R. suberifaciens, four strains of Rhizomonas sp., and 56 strains of unknown bacteria isolated from lettuce, prickly sowthistle and melon roots with symptoms of corky root. All these strains were tested for pathogenicity on lettuce, DNA homology with DNA of R. suberifaciens strain CA1, and cross‐reactivity with both MAbs in indirect antibody capture and indirect double antibody sandwich (DAS) ELISA tests. All strains of R. suberifaciens reacted with MAb‐Rs1 in both indirect ELISA tests, while none of the other strains reacted. In antibody capture indirect ELISA tests, MAb‐Rs2 had affinity to strains of R. suberifaciens from California and New York but not to those from Florida, Wisconsin and one from New York. In indirect DAS ELISA tests, MAb‐Rs2 reacted with all strains of R. suberifaciens. The indirect DAS ELISA tests were more sensitive than the indirect antibody capture tests.     

Major cysteine protease (cruzipain) in Z3 sylvatic isolates of <Emphasis Type="Italic">Trypanosoma cruzi</Emphasis> from Rio de Janeiro,Brazil

Trypanosoma cruzi, the etiologic agent of Chagas’ disease, is represented by a set of parasites which circulate between man, vectors, domestic and wild animals. Recently, our group isolated from Triatoma vitticeps strains of T. cruzi that were characterized as belonging to the Z3 phylogenetic lineage. Since very little is known about the biological and/or biochemical markers of sylvatic Z3 isolates, we have studied the protein and protease profiles of distinct Z3 isolates designated as SMM10, SMM53, SMM88, and SMM98. By means of sodium dodecyl sulfate-polyacrylamide gel electrophoresis, both quantitative and qualitative differences were observed in the protein profiles of these strains. All strains produced an acidic cysteine protease of 45 kDa, resembling cruzipain activity. The strain SMM10 synthesized an additional 55 kDa metalloprotease. Using Western blotting and anti-cruzipain antibody to detect cruzipain-like molecules, a 40-kDa reactive molecule was identified in all strains; in the strain SMM10, an 80-kDa protein was also reacted. Studies about cruzipain isoforms from sylvatic parasites could be valuable tools in the comprehension of the genetic variability in the pathogenesis of Chagas’ disease. S. A. O. Gomes and D. Misael contributed equally to this work.     

Evaluation of the protective efficacy of the anticoccidial vaccine Coccivac-B in broilers, when challenged with Egyptian field isolates of E. tenella

The present study was performed to explore the efficacy of the commercial anticoccidial vaccine (Coccivac B®) in broiler chickens using five field strains of Eimeria tenella that were isolated from five provinces in Egypt. This study also analyzed the ITS-1-rDNA sequence of these five strains and its corresponding sequence in the vaccine. In a floor pen experiment, 216 one-day-old commercial broiler chicks were classified into vaccinated and non-vaccinated groups. Each main group was classified into six subgroups. The chicks were challenged on the 28th day of age with 10⁴ sporulated oocysts of one of the five field strains of E. tenella. Our results indicated that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella. Aligning the ITS-1 sequences from the five strains with the ITS-1 sequence of E. tenella from the vaccine revealed 96 % sequence similarity with the Kafer El-Sheikh strain, 94 % with the Gharbia strain, 90 % with the Alexandria strain, and 78 % with the Matrouh and Behera strains. While interesting, these similarity values were not useful for predicting the protection conferred by the vaccine against the five field isolates. However, based on the data reported here, we can conclude that Coccivac B® produced variable degrees of protection in the birds infected with the five different strains of E. tenella     

Resistant strains ofPseudomonas aeruginosa isolated after exposure to several beta-lactam antibiotics

Successive transfer of three clinical isolates ofPseudomonas aeruginosa in liquid medium containing serial dilutions of several beta-lactam antibiotics was used to isolate resistant variants. The alpha-carboxy-penicillins (carbenicillin and ticarcillin), the acylureidopenicillins (piperacillin and azlocillin) and cephalosporins (moxalactam, cefoperazone, cefsulodin and ceftazidime) were used as the selective antibiotics. Resistant variants were isolated from two of the three strains (strains 27 and 45), using an inoculum size of 10⁴–10⁵ CFU/ml, which showed a mean 5 to 8-fold increase in MIC for most of the selected antibiotics. The 27-carbenicillin and 27-cefsulodin resistant variants showed beta-lactamase production similar to that of the parent. However, alterations were found in outer-membrane proteins and lipopolysaccharides. With azlocillin, moxalactam and ceftazidime as the selective antibiotics, resistant variants were isolated from strains 27 and 45 which showed a stable increased constitutive beta-lactamase production. From the third strain, 9150, the only variants isolated showed a two dilution-step increase in MIC to the antibiotics tested. The betalactamase production, outer-membrane proteins and lipopolysaccharides of these variants were similar to those of the parent.     

Isolation and Characterization of Small-Colony Variants of Ornithobacterium rhinotracheale

Ornithobacterium rhinotracheale is a Gram-negative bacterium associated with respiratory diseases in many avian species, with worldwide distribution, and it causes significant economic loss to the poultry industry. In this study, the isolation and characterization of O. rhinotracheale small-colony variants (SCVs) are described for the first time. O. rhinotracheale isolates (n = 27) were recovered from tracheal samples (n = 321) collected from different avian species with clinical signs of respiratory disease. Of the 27 O. rhinotracheale isolates, 21 (77.8%) showed SCVs in their primary cultures. Five O. rhinotracheale SCV isolates showed high levels of stability and were chosen for further characterization with their wild-type (WT) isolates. Stable O. rhinotracheale SCVs were oxidase negative, while their WT isolates were positive. Growth curves for stable O. rhinotracheale SCVs indicated lower growth rates and longer lag phases than for their WT isolates. Furthermore, it was possible to increase the efficacy of the broth medium in supporting the growth of O. rhinotracheale WT isolates by supplementing it with 5% fetal bovine serum (FBS) and 2% IsoVitaleX Enrichment. Antibiotic susceptibility tests showed that O. rhinotracheale SCVs had higher MIC values than their WT isolates. This study suggests that successful antibiotic treatment of respiratory diseases associated with O. rhinotracheale must take into consideration the resistance patterns of O. rhinotracheale SCVs. Intracellular persistence in murine RAW 264.7 macrophages revealed that O. rhinotracheale SCV28 had higher survival rates than its WT isolate. Finally, small-colony variants may be important contributors to the pathogenesis of O. rhinotracheale.     

Immunohistochemical and serological investigation of experimental Ornithobacterium rhinotracheale infection in chickens

Immunohistochemical techniques were used to prove that Ornithobacterium rhinotracheale was the causative agent of lesions in the air sacs and lungs in chickens, but only after infection with Newcastle Disease virus (NDV). At first, the bacteria attached to the epithelium of the air sacs. Subsequently, they infiltrated the air sacs, and caused thickening of the air sacs, the formation of oedematous and granulomatous tissue, and accumulation of macrophages. The infection peaked at 5 to 9 days, after which recovery was seen. In the lungs, some areas with bronchially-associated lymphoid tissue were affected. The other organs investigated were shown not to be affected. In the absence of NDV infection, aerosol exposure of chickens to O. rhinotracheale only resulted in minimal and temporary microscopic air sac lesions. No O. rhinotracheale cells or fragments could be detected at any time point later than 2 days post-exposure. In spite of the absence of visible lesions, chickens exposed to O. rhinotracheale without prior NDV infection reacted serologically. The duration and the titre of this immune response was indistinguishable from that obtained in chickens exposed after NDV infection. Thus, infection with O. rhinotracheale appears to be restricted to the respiratory tract, with lesions only evident in birds previously infected with NDV, even though a strong serological response can be established in the absence of prior viral infection.     

Identification and characterization of 31 isolates of <Emphasis Type="Italic">Borrelia burgdorferi</Emphasis> (Spirochaetales,Spirochaetaceae) obtained from various hosts and vectors using PCR-RFLP and SDS-PAGE analysis

Borrelia burgdorferi sensu lato, the etiologic agent of Lyme borreliosis, circulates between ticks and vertebrate hosts. Two main genospecies typically occur in the Czech Republic Borrelia garinii and Borrelia afzelii, transmitted generally by Ixodes ricinus (L., 1758) ticks. The aim of our study was to identify spirochaete isolates focusing on Borrelia burgdorferi acquired from different sources: vectors (ticks), potential vectors (mosquitoes, small mites) and hosts (wild rodents). In the years 1996–2001 a total of 2398 ticks, 72 mites (from wild rodents), 2700 mosquito adults, 1798 mosquito larvae and organ parts (kidney and spleen) of 216 wild rodents were collected from seven localities in the Czech Republic. A total of 31 spirochaete strains were isolated: 13 strains from ticks, 1 strain from mite (Haemogamasus sp.), 15 strains from rodents, 1 strain from mosquito adults and 1 strain from mosquito larva. For the genospecies identification of these isolates PCR, PCR-RFLP was used and their characterization was also performed by SDS-PAGE. By nested PCR method all except one isolated strains were detected as Borrelia burgdorferi s.l. Following PCR-RFLP molecular analysis results, tick isolates were identified as B. garinii and B. afzelii, the strain isolated from the mite was identified as B. afzelii. This is the first isolated strain of B.b.s.l. from a different mite of infraorder Parasitiformes than tick. All of rodent isolates were identified as B. afzelii; mosquito adult isolate was identified as B. afzelii. Larval isolate from mosquito is spirochaete, but does not belong to Borrelia burgdorferi sensu lato group.     

Antimicrobial Resistance Trends in Shigella Serogroups Isolated in Israel, 1990–1995

 From a total of 31 319 Shigella strains isolated in Israel between 1990 and 1996, 17 574 were sent to the National Shigella Reference Center for typing. Of these, 15 287 were identified as Shigella sonnei, 1833 as Shigella flexneri, 327 as Shigella boydii and 127 as Shigella dysenteriae. In all, 4395 strains were tested for sensitivity to ampicillin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol, nalidixic acid and ofloxacin. All strains tested were sensitive to ofloxacin, and only three strains were resistant to nalidixic acid. Only 113 of 3240 (3.5%) Shigella sonnei strains, 172 of 970 (17.7%) Shigella flexneri strains and 45 of 185 (24.3%) Shigella boydii strains tested were sensitive to four other antibiotic agents. The rates of resistance of Shigella sonnei, Shigella flexneri and Shigella boydii to trimethoprim-sulfamethoxazole were 94.4%, 51.3% and 61.6%, respectively. Rates of resistance to ampicillin among these species were 73.4%, 63.5% and 21.4%, respectively. The proportion of strains exhibiting multiple drug resistance was higher for Shigella sonnei than for the other serotypes studied. These results emphasize the need to reassess the use of antibiotic agents in the treatment of shigellosis.     

Detection and characterization of a bacteriocin,putadicin T01, produced by Pseudomonas putida isolated from hot spring water

Pseudomonas strains isolated from hot spring water were tested for bacteriocin‐like substance (BLS) production using a target panel of closely related microorganisms and other Gram‐positive and Gram‐negative bacteria. Molecular identification was carried out through specific PCR and 16S RNA sequence analysis. Isolates were identified as Brevundimonas diminuta and Pseudomonas putida, the latter exhibited antimicrobial activity. Pseudomonas putida strains produce an inhibitory substance against other Pseudomonas strains and other species including food‐borne pathogens. The BLS was sensitive to the proteolytic action of proteinase K, pronase E and trypsin but resistant to α‐amylase, RNase and lipase C, reflecting its proteinaceous nature. The BLS was stable at 100 °C and also after thermal treatment at 121 °C for 15 min. Additionally, it was stable within a wide range of pH (2–10). The substance from P. putida T01 strain was bactericidal to Escherichia coli. SDS‐PAGE analysis of the partial purified supernatant of strain T01 revealed a BLS with an approximate molecular mass of 8 kDa. Therefore, the results of this study show that P. putida strain T01 produces a BLS with a higher activity spectrum, which may find application in human medicine and in minimally processed food preservation.     

Cross protection studies with Eimeria maxima strains

The purpose of this study was to determine whether differences in fecundity of Eimeria maxima isolates were related to their abilities to elicit cross-protective immunity. Immunizations were initiated by low-dose gavages of sporulated oocysts to day-old broiler chicks under conditions that allowed parasite recycling, and chickens were challenged with homologous and heterologous strains. Immunization efficacies were measured using a protective index calculated from weight gain, gross lesion score, plasma carotenoid, and NO₂^– + NO₃^– data. A 4×4 cross- immunization study of four E. maxima strains (designated A–D) showed that strain A, which displayed the lower fecundity, provided no cross-protection against the other three strains. Following several maintenance passages, the fecundity of strain A was increased to that of strain C, and infection with strain A oocysts was able to provide cross-immune protection against challenge with strain C. This study indicates that parasite fecundity is important in providing good immune stimulation, and should be carefully monitored when characterization of the unique immune potentials of Eimeria strains is undertaken.Prepared for Parasitology Research     

Strain Characterization of Candida parapsilosis Fungemia by Molecular Typing Methods

 The present study used two molecular typing methods to investigate a cluster of eight cases of Candida parapsilosis fungemia in a hospital in Rio de Janeiro, Brazil. Candida parapsilosis is an important opportunistic pathogen that is frequently involved in outbreaks of nosocomial fungemia. Identification of a common source of infection and determination of genetic relatedness among the strains involved in outbreaks are important for infection control. Candida parapsilosis strains were isolated from the bloodstream of patients housed in an intensive-care unit (n=5) and in individual rooms (n=3). An additional strain of Candida parapsilosis was isolated from a hyperalimentation infusion flask, which was implicated by molecular typing to be the source of infection. All strains were identified using morphological and biochemical methods. The genetic relationship between patients' strains and the hyperalimentation infusion strain was assessed by electrophoretic karyotype (EK) analysis and random amplification of polymorphic DNA (RAPD). Both methods resulted in patterns that allowed differentiation of the isolates. Candida parapsilosis fungemia, in three of the eight patients, resulted from a common source of infection, as demonstrated by molecular typing methods. Image analysis of EK patterns indicated that these strains were closest to Candida parapsilosis Group II, a grouping that is a less frequent clinical isolate than the major Group I strains.     

Enterococcus cecorum infections in broiler breeders and their offspring: molecular epidemiology

Increased mortality and problems with lameness were reported in Dutch broiler flocks from the year 2008 onwards. Therefore, a field inventory, including 10 affected broiler flocks, nine corresponding broiler breeder flocks and five hatcheries, was carried out. The onset of clinical signs (lameness and increased mortality) started at about 2 weeks of age. The flock mortality varied from 3.1 to 8.1% at slaughter. Post-mortem lesions of broiler flocks were characterized by the occurrence of pericarditis/hydropericardium, arthritis and femoral head necrosis. Enterococcus cecorum was isolated from approximately 30% of the lesions. In the broiler breeders, E. cecorum was not isolated from any of the lesions. However, it was isolated from 31 out of 65 (47%) cloacal swabs, from two out of 65 (3%) oviduct samples, from one out 65 (1.5%) bone marrow samples and from two out of 25 (8%) blood samples. E. cecorum was not isolated from the air samples or dead-in-shell originating from the hatcheries involved. In total, 78 isolates were subjected to further typing by means of tRNA intergenic spacer PCR and confirmed as E. cecorum. The genetic relatedness of these cocci was subsequently studied using pulsed-field gel electrophoresis. The banding patterns of approximately 68% of E. cecorum isolates originating from parent stock flocks were clonal to one or more isolates of the same or other parent flocks. In contrast, isolates originating from their diseased offspring showed much greater genetic variation. Therefore, the vertical transmission of E. cecorum could not be demonstrated.     

Prevalence and severity of osteochondrosis of the free thoracic vertebra in three modern broiler strains and the Athens Canadian Random Bred control broiler

Osteochondrosis (OCD) results from a disturbance of endochondral ossification in articular cartilage and is an important cause of lameness in several animal species, including chickens. OCD lesions in the free thoracic vertebra (FTV) of chickens are essential to the pathogenesis of pathogenic Enterococcus cecorum. The goal of this study was to determine the prevalence of OCD in the FTV among three modern broiler chicken crosses (strains A/A, A/B, and C/C) and Athens Canadian Random Bred (ACRB) chickens, which served as the control group. The effect of sex, age, strain, body weight, and incubation temperature profile on OCD severity for each group was determined. At 2, 4, 6, and 8 weeks of age, the FTV of 10 male and 10 female birds from each strain exposed to either optimal or low-early, high-late incubation temperature profiles were collected and scored histologically for OCD lesion severity. OCD spectrum lesions were detected in >70% of all strain/sex combinations, including the ACRB controls. No association was observed between mean OCD score and broiler strain, incubation temperature profile, sex, age, or body weight. These findings indicate that OCD of the FTV is common in broiler chickens with similar prevalence observed in broilers with modern genetics and the ACRB broilers which represent 1950s broiler genetics. As the parameters examined did not have a statistical correlation with OCD, additional work is needed to understand factors that contribute to development of OCD in chickens.     

Analysis of the 5.8S rRNA and internal transcribed spacers regions of the variant <Emphasis Type="BoldItalic">Naegleria fowleri</Emphasis> Thai strain

The aim of this study was to analyze the internal transcribed spacers regions (ITS) of the of 5.8S ribosomal RNA (rRNA) gene of four isolants of Naegleria fowleri. Three of four Thai strains were isolated from patients and one from the environment. All four strains were confirmed to be N. fowleri by species-specific PCR using DNA extracted using a QIAamp DNA mini kit. The ITS lengths observed were ITS1, 85 bp; ITS2, 106 bp; and 5.8S, 176 bp. Five discriminating deca-nucleotide primers A1, A15, B10, B12, and B15 were used in this study. Specific prominent bands were observed after PCR with each primer: 600 bp with A1; 615 bp with A15; 1580 bp with B10; 930 and 510 bp with B12; and 310 bp with B15. All sequences were compared with the Japanese J16-1-42E sequence in the Genbank database. After alignment, our sequences contained only 0.5% variation from the J16-1-42 sequence. The ITS main products of the strain from the environment were similar to those of the three strains from Thai patients. The four Thai strains have essentially the same 5.8S rRNA genes as Cattenom Japanese J16(1) 42E strain.