Campylobacter spp. contamination of chicken carcasses during processing in relation to flock colonisation.

The presence and numbers of campylobacters on chicken carcasses from 26 slaughter groups, originating from 22 single-house flocks and processed in four UK plants, were studied in relation to the level of flock colonisation determined by examining the caecal contents of at least ten birds per group. The prevalence of campylobacters on carcasses from five campylobacter-negative flocks processed just after other negative flocks was low (8.0 log(10) cfu) than carcasses originating from low prevalence flocks (average of 2.3 log(10) cfu; range: <1.1 to 4.1 log(10) cfu). There was a reduction in the numbers of campylobacters on carcasses between plucking and chilling in eight of ten fully colonised flocks. In another eight flocks, a significant (P<0.001) decrease (0.8 log(10) cfu) in the number of campylobacters on carcasses from just before to after chilling was detected. Campylobacter spp. could be isolated from aerosols, particles and droplets in considerable numbers in the hanging-on, defeathering and evisceration areas but not in the chillers. This was the case even when campylobacters were not isolated from the target flock. Campylobacters on carcasses from two partly colonised flocks were either the same subtype, as determined by speciation, Multi-Locus Sequence Typing (MLST) and flaA Restricted Fragment Length Polymorphism (RFLP) typing, as those in the fully colonised flocks processed previously, although not necessarily the most prevalent ones; or were the same subtypes as those found in the caeca of the flock itself. The prevalences of the different campylobacter subtypes found on carcasses from two fully colonised flocks did not closely reflect those found in the caeca. MLST combined with flaA RFLP provided a good method for ascertaining the relatedness of strains isolated from carcasses and caecal contents. This study showed that carcass contamination is related to the within-flock prevalence of campylobacter colonisation, but that contamination from previously processed flocks was also significant, especially on carcasses from low prevalence flocks. Forced dry air cooling of carcasses reduced contamination levels.

Bacterial variants in urinary casts and renal epithelial cells.

Casts with numerous and unusually large granules were seen in the urine of a child with renal Fanconi's syndrome. When the urine sediment was sealed under a coverslip for several days, many granules changed to filamentous bacterial variants that segmented and, finally, appeared as streptococcal-like forms. When the patient's blood was cultured by a special method, bacterial variants grew consistently, and frequently reverted to parent coccal forms, although conventional cultures were negative. Variants from blood cultures had the same morphology and staining properties as granules in casts and in cystic structures found within hypertrophied renal pelvic epithelial cells. Cryptic parasitization with bacterial variants probably occurs in many nephropathies. Variants are known to produce toxins and immunogens, which could lead to mesangial and basement membrane deposits as well as to occlusive reactions in the renal microcirculation.

Antigenic and immunogenic characteristics of subcellular fractions and whole cells of a rough E. coli 0111 (J5) mutant.

Little information is available on the antigenic and immunogenic properties of an E. coli rough mutant: J5 derived from E. coli 0111:B4, and the relationship of J5 to other cross-reacting antigens of Enterobacteriaceae. Subcellular fractions of J5 and various antigen preparations were tested against antisera to Enterobacterial Common Antigen (ECA-Kunin) and to the Re mutant of S. minnesota (R595). ECA-Kunin was demonstrated in all subcellular fractions of the J5 mutant by means of indirect hemagglutination and by hemagglutination inhibition tests. This common antigen was separable from J5 LPS by ethanol fractionation and by phenol-chloroform-petroleum ether extraction. Treatment with alkali destroyed the hemagglutinating reactivity of ECA-Kunin and revealed the complex nature of J5 surface antigens; an alkalinized 20p30 fraction (containing cell wall components) contained both specific J5 antigen and an antigen which cross-reacted with S. minnesota and S. typhimurium. This antigen was shown by absorption studies to be a new common antigen other than Re LPS or ECA-Kunin. Studies of J5 LPS by ELISA demonstrated that there was a shared cross-reactive immunodeterminant between the glycolipids of J5 and Re. Accordingly, heat-killed J5 preparations were complex vaccines which were able to elicit an antibody response with at least two specificities: ECA-Kunin and the specific J5 antigen.

Antibodies to Escherichia coli 06 porins cross-react with urinary pathogens.

Antibodies to partially purified E. coli 06 35-40 KDa porin trimers recognized the reactive epitopes in the intact porin surface molecule present in various wild-type, heterologous, urinary pathogens. The presence of lipopolysaccharide in the membrane did not shield the antibody binding sites. The reactivity was shown to be specific for porins since LPS-absorbed porin antisera reacted with porins on immunoblots and showed no reactivity with LPS. Additionally, the cross-reactions were abolished by absorption of the porin antisera with E. coli 06 containing porin trimers. These data strengthen the rationale for exploring the enhancement of immunoprotection by monoclonal antibodies to specific immunoreactive antigens in the porin molecule.

Vasectomy in rhesus monkeys I. Surgical techniques and gross observations.

Vasectomy and vaso-occlusion techniques were used in 47 male rhesus monkeys to maximize and minimize the amount of sperm allowed to escape from the vas into surrounding tissues for up to seventy-two weeks postoperatively. Body weight changes and blood clinical data indicated that the general health of all the monkeys remained good. Normal seasonal changes in body weights and testicular volumes suggested that there were no disturbances to the endocrine system and that the monkeys remained responsive to seasonal environmental stimuli. Vasectomy appears to cause no short-term deleterious effects in the rhesus monkeys, based on observations made during the seventy-two weeks that these monkeys were study after vasectomy. This conclusion agrees with the findings of other investigators.

Vasectomy in rhesus monkeys. III. Light microscopic studies of testicular morphology.

Rhesus monkeys were randomly assigned to undergo various surgical procedures. The animals were followed from one to sixty-six weeks postvasectomy, at which time they were sacrificed and their tissues prepared for light and electron microscopy. Vasectomy in the rhesus monkey, as in certain other species, appears to be a procedure not attended with widespread testicular atrophy or histologic evidence of impaired spermatogenic potential utilizing the procedures and postoperative periods studied. Why certain animals exhibited focal degenerative changes is unclear; perhaps a certain population, yet to be defined, is more sensitive to such procedures, resulting in testicular alterations. It is important that such a population and such changes be defined to predict more accurately the possibility of successful vasovasostomy and reestablishment of fertility.

Bacterial doubling time modulates the effects of opsonisation and available iron upon interactions between Staphylococcus aureus and human neutrophils.

Staphylococcus aureus was grown exponentially at two doubling times (DT), one related to in vivo (DT 60 min) and one typical of laboratory conditions (DT 24 min), and under iron-poor and iron-rich conditions. Relative to the fast-grown phenotypes, both slow-grown phenotypes exhibited low surface hydrophobicity and low protein A expression, induced poorly in non-opsonised and opsonised chemiluminescence, and survived well in whole blood killing. In particular, slow-grown, iron-poor cocci demonstrated enhanced survival in whole blood killing which correlated with significant reduction in their association with polymorphonuclear leukocytes, compared to the three other phenotypes; iron sufficiency increased the ability to stimulate polymorphonuclear leukocytes irrespective of opsonisation status. Staphylococcal DT may, by influencing surface hydrophobicity, modify interactions with immune system components.

Culture of seminal fluid in a fertility clinic.

To determine whether the culture of seminal fluid in a fertility clinic is of importance, bacterial cultures were obtained in a consecutive series of 96 patients. Routine bacteriologic cultures were performed within 1 hour of collection. Ureaplasma urealyticum (T-mycoplasma) cultures were also obtained in the last 31 of the patients in this series. Of these 96 patients, 11% showed significant bacterial growth (greater than 10(4) colonies/ml) in the semen specimens, 8% in those patients with normal semen analyses and 14% in those with abnormal analyses. Fifty-eight per cent of semen specimens were positive for U. urealyticum. In reference to normal and abnormal semen analyses the distribution was the same regardless of the presence or absence of U. urealyticum. Antibiotic treatment resulted in minor changes in motility and morphology in a few patients despite conversion to a negative culture. Cultures were also coordinated with microscopic urinalysis and the presence of white blood cells or bacteria in stained smears of semen. There were no significant differences between groups with positive or negative cultures. Trichomonas vaginalis was not seen.

Studies on sperm antigenicity, 5. In vivo and in vitro cellular reactivity in guinea pigs sensitized with fractions of human spermatozoa.

In vitro delayed type hypersensitivity was demonstrated with peritoneal exudate cells from guinea pigs immunized with different preparations of human and guinea pig seminal components emulsified with complete Freund's adjuvant-H37Ra. The seminal components were intact human spermatozoa (HuSp); intact guinea pig spermatozoa (GPSp); human seminal plasma (HuSePlFr); and fractions of human spermatozoa obtained by centrifugation of the homogenate at 5,000 X g (5S30 and 5p30), at 20,000 X g (20S30 and 20p30), and at 144,000 X g (144p120). Cellular sensitivity was demonstrated in vivo by skin testing and in vitro by the macrophage inhibition technique. Peritoneal exudate cells from guinea pigs sensitized with fractions 5p30 and 20p30 elicited a delayed hypersensitivity reaction which could be detected only with intact human spermatozoa. Other human spermatozoal fractions (5S30, 20S30, and 144p120) were weak immunogens. Sensitization of guinea pigs with fractions of human spermatozoa, in addition to causing delayed hypersensitivity reactions, elicited low titers of spermatoxic antibodies. Antibodies to human spermatozoal fractions 5S30, 5p30, 20S30, and 20p30 cross-reacted with intact human spermatozoa and intact guinea pig spermatozoa. It is postulated that the existence of "spermatozoa-specific" coating antigen(s) derived from other components of the reproductive tract might be responsible for human spermatozoal antigenicity.

Growth of Salmonella enteritidis in artificially contaminated eggs: the effects of inoculum size and suspending media.

Growth profiles of two isolates of Salmonella enteritidis phage type (PT) 4 inoculated into either the albumen of whole shell eggs or into separated albumen were found to be markedly affected by the size of the inoculum and the composition of the medium used to suspend the cells prior to inoculation. Using our model with an inoculum of two cells, multiplication of the Salmonella was not seen in 93% of eggs held at 20 degrees C for 8 days. In approximately 7% of eggs, however, growth occurred during the 8 days of storage. If the inoculum equaled or exceeded 25 cells per egg when eggs were subsequently stored at 20 degrees C, or 250 cells per egg when eggs were stored at 30 degrees C, high levels of growth of Salmonella in the egg occurred significantly more frequently than when the inoculum was two cells. High levels of growth were also seen more frequently if the inoculum was suspended in buffered peptone water or maximal recovery diluent rather than in phosphate buffered saline. Growth of Salmonella in separated albumen occurred very infrequently (1.1% of samples) at low inoculum levels and did not become significant until the inoculum was 250 cells or greater. Growth in the albumen was unaffected by the composition of the suspending medium. Provided that the inoculum was approximately 2 cells per egg and the bacteria were suspended in PBS, observed growth profiles of S. enteritidis inoculated into the albumen of whole eggs resembled those in naturally contaminated eggs.

Prevalence of antibiotic resistance and serotypes in pneumococci in England and Wales: results of observational surveys in 1990 and 1995.

OBJECTIVE: To assess the prevalence of antibiotic resistance and serotype distribution among pneumococci in England and Wales in 1990 and 1995. DESIGN: Observational surveys in March 1990 and March 1995. During two weeks in each survey period all pneumococci isolated in public health laboratories in England and Wales were collected and assessed for sensitivity to antibiotics and the distribution of serogroups or serotypes. SETTING: The network of public health laboratories throughout England and Wales. SUBJECTS: 1127 individual patient isolates of Streptococcus pneumoniae obtained during the two surveys. MAIN OUTCOME MEASURES: Sensitivity or resistance to a range of antibiotics; serogroup or serotype. RESULTS: The prevalence of intermediate or full resistance to penicillin increased from 1.5% in 1990 to 3.9% in 1995 and resistance to erythromycin increased from 2.8% to 8.6%. About 92% of isolates belonged to serogroups or serotypes included in the currently available pneumococcal vaccine. CONCLUSION: Resistance to penicillin and erythromycin has increased among pneumococci in England and Wales. Continued surveillance to assess further increases in the prevalence of pneumococcal resistance to antibiotics is essential.

A high oxfendazole dose to control porcine cysticercosis: pharmacokinetics and tissue residue profiles.

Oxfendazole (OFZ) is efficacious for porcine cysticercosis at 30 mg/kg. OFZ is not registered to be used at this dose. The assessment of the OFZ and metabolites [(fenbendazole sulphone (FBZSO2), fenbendazole (FBZ)] plasma pharmacokinetic and tissue residue profiles after its oral administration to pigs and the withdrawal period for human consumption were reported. Forty-eight pigs allocated into two groups received OFZ (30 mg/kg) orally as a commercial (CF) or as experimental formulation (SMF). Samples (blood, muscle, liver, kidney and fat) were collected over 30 days post-treatment and analyzed by HPLC. OFZ was the main compound recovered in plasma, followed by FBZSO2 and low FBZ concentrations. OFZ AUC0-LOQ (209.9±33.9 µg·h/ml) and Cmax (5.40±0.65 µg/ml) parameters for the CF tended to be higher than those for the SMF (AUC0-LOQ: 159.4±18.3 µg h/ml, Cmax: 3.80±0.35 µg/ml). The highest total residue (OFZ+FBZSO2+FBZ) concentrations were quantified in liver, followed by kidney, muscle and fat tissue. FBZSO2 residue levels were the highest found in muscle (0.68±0.39 µg/g) and fat (0.69±0.39 µg/g). In liver and kidney the highest residues corresponded to FBZ (5.29±4.36 µg/g) and OFZ (2.86±0.75 µg/g), respectively. A withdrawal time of 17 days post-treatment was established before tissues are delivered for human consumption.

Reduction of irrelevant and redundant data from TFRs for EEG signal classification.

Time-frequency representations (TFR) are one of the most popular characterization methods for non-stationary biosignals. Despite of their potential advantages, these representations suffer of large quantity of redundant and irrelevant data which makes them difficult to use for classification purposes. In this work, a methodology for reduction of irrelevant and redundant data is explored. This approach consists on removing irrelevant data, applying a relevance measure on the t-f plane that measures the dependence of each t-f point with the class labels. Then, principal component analysis (PCA) and partial least squares (PLS) are used as non-supervised and supervised linear decomposition approaches to reduce redundancy of remaining t-f points. Results show that the proposed methodology improves the performance of classifier up to 3% when no relevance and redundancy on TFRs is reduced.

Sources of Campylobacter spp. colonizing housed broiler flocks during rearing.

The study aimed to identify sources of campylobacter in 10 housed broiler flocks from three United Kingdom poultry companies. Samples from (i) the breeder flocks, which supplied the broilers, (ii) cleaned and disinfected houses prior to chick placement, (iii) the chickens, and (iv) the environments inside and outside the broiler houses during rearing were examined. Samples were collected at frequent intervals and examined for Campylobacter spp. Characterization of the isolates using multilocus sequence typing (MLST), serotyping, phage typing, and flaA restriction fragment length polymorphism typing was performed. Seven flocks became colonized during the growing period. Campylobacter spp. were detected in the environment surrounding the broiler house, prior to as well as during flock colonization, for six of these flocks. On two occasions, isolates detected in a puddle just prior to the birds being placed were indistinguishable from those colonizing the birds. Once flocks were colonized, indistinguishable strains of campylobacter were found in the feed and water and in the air of the broiler house. Campylobacter spp. were also detected in the air up to 30 m downstream of the broiler house, which raises the issue of the role of airborne transmission in the spread of campylobacter. At any time during rearing, broiler flocks were colonized by only one or two types determined by MLST but these changed, with some strains superseding others. In conclusion, the study provided strong evidence for the environment as a source of campylobacters colonizing housed broiler flocks. It also demonstrated colonization by successive campylobacter types determined by MLST during the life of a flock.

Filterable cell-associated cryptic bacterial forms in immunologic renal diseases.

Blood and urine derived from patients with certain types of nephritis contain filterable (0.22 mu.) bacterial forms, which heretofore have not been considered as possible etiologic agents in those diseases. Furthermore, these cryptic bacterial forms are overlooked by conventional culture techniques. It is hypothesized that the organisms and/or host-cell-variant-bacterial antigen complexes could be the initiators of immunopathologic events in various types of immunologic renal diseases.