Factors affecting the clinical relevance of Corynebacterium striatum isolated from blood cultures

This study aimed to identify clinical or microbiological factors affecting the clinical relevance of Corynebacterium striatum isolated from blood cultures. A total of 64 isolates from 51 patients identified as C. striatum by matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing were assessed. More than two blood cultures were positive in 25 (48.1%) patients. Diabetes, solid tumor, and a history of previous exposure to antibiotics were more common in patients with multiple positive blood cultures. Charlson comorbidity scores were also higher, and more isolates were recovered after 48 hours of hospital stay in patients with multiple positive blood cultures. Strains recovered from patients with multiple positive blood cultures produced significantly more biofilm. Based on multilocus sequence typing (MLST), sequence type (ST) 20 (31.3%) was the most dominant, followed by ST2 (20.3%) and ST23 (10.9%). There was no relationship between the number of positive blood culture sets and sequence typing. In multivariate analyses, Carlson comorbidity score (odds ratio [OR], 1.91; 95% confidence interval [CI], 1.09–3.36; P = 0.03) and biofilm formation were associated with multiple positive blood cultures (OR, 17.43; 95% CI, 3.71–81.91; P = 0.03). This study provides evidence that the biofilm phenotype could contribute to determining the clinical significance of C. striatum in patients with severe underlying conditions. The predominance of certain STs suggests the relatedness of C. striatum infection and the nosocomial environment.

Caprine arthritis encephalitis and caseous lymphadenitis in goats: use of bulk tank milk ELISAs for herd-level surveillance

The objective of this study was to evaluate the diagnostic performance of two ELISA tests applied to bulk tank milk (BTM) as the first part of a two-step test scheme for the surveillance of caprine arthritis encephalitis (CAE) and caseous lymphadenitis (CLA) infections in goats. The herd-level BTM tests were assessed by comparing them to the test results of individual serological samples. The potential for refining the cut-off levels for BTM tests used as surveillance tools in a population recently cleared of infection was also investigated. Data was gathered on serum (nCAE =9702 and nCLA=13426) and corresponding BTM (nCAE=78 and nCLA=123) samples from dairy goat herds enrolled in the Norwegian disease control and eradication programme 'Healthier Goats'. The results showed that the sensitivity and specificity of the CAE ELISA BTM test with respect to detecting ≥2 per cent within-herd prevalence were 72.7 per cent and 86.6 per cent, respectively. For the CLA ELISA BTM the sensitivity and specificity were 41.4 per cent and 81.7 per cent, respectively, for the same goal of detection. The results suggest that BTM testing can be applied as a cost-effective first step for early detection of CAE and CLA infection.

Serological studies on Corynebacterium pseudotuberculosis infections in goats in Baden-Wuerttemberg (Germany) and seroreactions on antigens used for newly developed enzyme-linked immunosorbent assays (ELISA)

In the present study, comprehensive data on the seroprevalence of Corynebacterium (C.) pseudotuberculosis infections in goats are presented for Baden-Wuerttemberg, a Federal State of Germany, for the first time. As a prerequisite, ELISAs based on a recombinant phospholipase D (rPLD) and whole cell antigens (WCA) were designed and validated yielding sensitivity values of 81% and 97% and specificity values of 98% and 99%, respectively. Immunisation trials in goats demonstrated a significant production of antibodies to rPLD but an evidently lower antibody production to WCA as determined in the corresponding ELISA. Moreover, immunisation with rPLD resulted in the formation of antibodies, which were also detected in the WCA ELISA. In contrast, this phenomenon was not observed with the rPLD ELISA after immunisation with WCA. Implementation of the rPLD and WCA ELISAs in a broad-based seroprevalence study in Baden-Wuerttemberg revealed positive reactions in both ELISAs in 13.2% of the 1771 goat sera tested. In 53.7% of 121 herds of which five or more animals were tested per herd there was at least one animal that showed a positive reaction in both tests.

Development and validation of an ELISA to detect antibodies to Corynebacterium pseudotuberculosis in ovine sera

Several enzyme-linked immunosorbent assays (ELISAs) have been developed for the detection of antibodies to Corynebacterium pseudotuberculosis, the causative agent of caseous lymphadenitis (CLA). However, none are commercially available in the UK. It was therefore necessary to develop a new, economic ELISA for use in a research project studying the epidemiology of CLA in UK sheep. The ELISA with its diagnostic qualities is presented. The ELISA was developed using sonicated C. pseudotuberculosis and optimised to detect total antibody or IgG class antibody in serum. Receiver operating characteristic (ROC) curves were obtained and the area under the ROC curve was used to compare the sensitivity and specificity of the two ELISAs. Both versions of the ELISA were evaluated on a panel of 150 positive reference sera and 103 negative reference sera. Using the test at 100% specificity, the sensitivity of detection of total antibody was 71% (95% confidence interval 63-78%), and the sensitivity of detection of IgG antibody to C. pseudotuberculosis was 83% (76-89%), which compares favourably with other reported ELISA tests for CLA in sheep. The sensitivity of the IgG antibody assay may be higher because of the greater affinity of IgG class antibodies compared with the IgM antibodies also detected by the total antibody ELISA. The results of ROC analysis indicated that the IgG isotype ELISA was more accurate than the total antibody ELISA. The efficiency of the test was greatest when serum samples were run in a dilution series than when any single serum dilution was used. The ELISA is considered to be suitable for application in field studies of CLA in UK sheep.

Effects of different stressors in haematological variables in cultured Oreochromis aureus S

Since haematological variables can be used to assess the health state in cultured fish, a haematological characterization of clinically healthy Oreochromis aureus was done to establish the reference indices of this species. Fish were subjected to different stressed conditions (bacterial infection, nitrite intoxication, malachite green overdose) to study the changes in the haematological indices and its relation with the health condition. This species showed microcytic anaemia under experimental bacterial infection by Corynebacterium sp.; anaemia, neutrophilia and erythrocytes deformation following nitrite intoxication and medication overdose with malachite green.

Experimental Corynebacterium pseudotuberculosis mastitis in dairy cows

The inoculation of 2000 colony-forming units of Corynebacterium pseudotuberculosis into one teat canal of each of three cows resulted in severe, chronic, pyogranulomatous mastitis. Within three days the cows had a reduced haematocrit, haemoglobin concentration and red cell count. The anaemia was initially normocytic, normochromic and non-regenerative, and was associated with a brief peak of neutrophilia; a regenerative response became evident two to three weeks later. Clinical signs of mastitis appeared seven to 14 days after the inoculation, with a peak of high fever, more severe anaemia, a second peak of neutrophilia and the complete cessation of milk production from all quarters; extensive and severe pyogranulomatous mastitis developed in the inoculated quarters. No other lesions were detected postmortem, and C pseudotuberculosis was cultured from the affected quarters but not from the supramammary lymph nodes and viscera.

An interferon-gamma assay for diagnosis of Corynebacterium pseudotuberculosis infection in adult sheep from a research flock

The optimal method of control of caseous lymphadenitis of sheep caused by Corynebacterium pseudotuberculosis is eradication of infection by identification and removal of infected carrier animals. Current serological approaches to identification of infected sheep are generally hampered by low sensitivity and specificity of available tests. The objective of this study was to develop a whole blood assay for detection of C. pseudotuberculosis-infected sheep, based on detection of IFN-gamma response to whole cell C. pseudotuberculosis antigens, and to determine the reliability of the assay. A commercially available bovine interferon-gamma assay enzyme-linked immunosorbent assay was used and the test optimised using experimentally infected sheep. The assay was also tested on known CLA-negative sheep. Setting a IFN-gamma optical density cut-off at 0.100 as positive under the conditions used, the test detected C. pseudotuberculosis experimentally infected sheep over a 450-day period with a reliability of 95.7%. It identified known non-infected sheep with a reliability of 95.5%. Repeated vaccination of three uninfected sheep with a commercially available bacterin-toxoid vaccine did not interfere with the assay. The IFN-gamma response of sheep whole blood to C. pseudotuberculosis antigens offers promise for use in a test-and-removal approach to eradication of CLA in sheep.

Effect of the interval between shearing and dipping on the spread of Corynebacterium pseudotuberculosis infection in sheep

OBJECTIVE

To determine whether the spread of Corynebacterium pseudotuberculosis infection to sheep in dips could be controlled by increasing the time between shearing and dipping.

DESIGN

A controlled treatment trial where only the time between shearing and dipping was varied. ANIMALS AND PROCEDURE: One hundred and ninety-five sheep were found to be negative for C. pseudotuberculosis exposure by assay of CLA toxin antibody, were divided into four treatment groups. Each was shorn at either 0, 2, 4 or 8 weeks before dipping in a solution containing C. pseudotuberculosis. Blood samples were taken 6 weeks after dipping and sheep were slaughtered 12 weeks after dipping. A fifth smaller group of 14 sheep shorn 26 weeks before dipping, was also exposed to C. pseudotuberculosis and was slaughtered with the other sheep.

RESULTS

The occurrence of caseous lymphadenitis abscesses did not differ between groups or with sheep shorn 26 weeks before dipping. The proportion of sheep that seroconverted to the C. pseudotuberculosis toxin and cell wall ELISA was larger in sheep dipped immediately after shearing than in sheep in the other groups.

CONCLUSIONS

Delaying dipping until 8 weeks after shearing did not decrease the C. pseudotuberculosis infection rate due to dipping. Sheep dipped immediately after shearing developed higher concentrations of antibody to C. pseudotuberculosis than sheep when dipping occurred between 2 and 8 weeks and later after shearing.

Caseous lymphadenitis in goats: the pathogenesis, incubation period and serological response after experimental infection

Twenty goats, in two groups of 10, were injected intradermally with Corynebacterium pseudotuberculosis. The doses of infection were 1 x 10(5) and 5 x 10(4) colony-forming units (cfu) for groups 1 and 2, respectively. Thereafter, a goat from each group was killed every 2-3 days and examined for gross and microscopic caseous lesions in the draining lymph nodes. Bands or zones of macrophages and polymorphonuclear granulocytes were observed microscopically on the second day of infection in both groups. Gross caseous lesions were observed from days 8 and 9 of infection, respectively. Positive bacterial agglutination test and haemolysis inhibition test titres were detected after 15-17 days and 20-25 days of infection, respectively. These results indicated that caseous lymphadenitis is a subacute disease with an incubation period of 8-9 days, but that it is not detectable serologically until after 15 days of infection.

Development of an ELISA for the diagnosis of Corynebacterium pseudotuberculosis infections in goats

An ELISA was developed for the diagnosis of Corynebacterium pseudotuberculosis infections in goats. A bacterial whole cell extract was used as solid-phase antigen, and serum from a culture-positive animal served as the internal reference standard. The well-to-well and assay-to-assay variations were determined to be 12.7 and 33.0%, respectively. A cut off value was determined by parallel testing of 142 sera (112 ELISA-positive, 30 ELISA-negative) in a Western blot, and the correlation between both tests was highly significant (K=0, 93). In addition, the reliability of the ELISA for the detection of infected herds was proven in a double blind study testing 910 sera from 74 goat herds.

Acute-phase proteins in perinatal human plasma

Plasma from eight newborns (4 pre-term and 4 full-term) with early-onset (< 72 h) sepsis and six apparently healthy controls was analyzed. The presence of spots identified as haptoglobin and serum amyloid A protein was the electrophoretic result most consistently associated with disease. Time course monitoring showed rises, peaks and declines of spot intensity as expected for acute-phase proteins induced by transient stimuli. Haptoglobin beta chains appear to be undersialated in pre-term newborns, whereas post-translational modifications of alpha chains and serum amyloid A protein are similar to those observed in adults. The undersialation of beta chain and occurrence of alpha chain phenotypes different from those found in maternal serum indicate that perinatal haptoglobin originates from neonatal synthesis.

Corynebacterium jeikeium bacteremia at a tertiary care center

During a six-year period 23 patients with isolation of Corynebacterium jeikeium (formerly known as Corynebacterium group JK) from one or more blood cultures at a university hospital were identified. Cases occurred sporadically without time- or ward-related clustering. Review of the cases showed that most infections were nosocomial, that most of the patients had underlying malignant disease, had a chronic intravascular catheter implanted, had been pretreated with antibiotics, and were neutropenic at the time the blood cultures were drawn. Patients with only one versus those with more than one positive blood culture differed in some important aspects. Patients with only one positive blood culture were less likely to have acute leukemia, had significantly higher neutrophil counts and a shorter duration of preceding antibiotic treatment, and all had other probable causes of infection and fever. The mortality also appeared to be lower in these patients. Despite the possibility of increasing frequency of blood cultures positive for C. jeikeium, severe infections due to this organism continue to be largely confined to neutropenic patients with hematologic malignancy.

Alterations in the phospholipid composition and morphology of ovine erythrocytes after intravenous inoculation of Corynebacterium pseudotuberculosis

Corynebacterium pseudotuberculosis produces a sphingomyelin-specific phospholipase D exotoxin that is a major determinant in the pathogenesis of caseous lymphadenitis. The effect of this exotoxin on erythrocytes was assessed during experimentally induced infection of sheep. Blood was drawn at timed intervals, and the phospholipid composition of erythrocytes was determined by use of high-performance liquid chromatographic analysis of membrane extracts. Erythrocyte morphology was determined by use of transmission electron microscopy. Significant (P less than or equal to 0.05) decreases in erythrocyte membrane sphingomyelin content and significant (P less than or equal to 0.05) increases in phosphatidylglycerol content were observed 30 minutes after IV inoculation of C pseudotuberculosis. The concentration of other phospholipids remained unchanged. Initially, spherostomatocytes were formed that later became pitted at the cell surface. These pits or invaginations appeared as numerous vacuoles at the periphery of thin-sectioned cells. Pitting became progressively worse, leading to an extensive scalloped cell surface. Alterations in the phospholipid composition and morphology of ovine erythrocytes may contribute to pathophysiologic findings in sheep with acute infection induced by C pseudotuberculosis.

[Isolation of Corynebacterium JK from the blood of neutropenic patients with septic diseases]

The authors report on the isolation of Corynebacterium JK from the blood of two neutropenic patients with hematological malignancy. In Hungary this paper is the first to discuss the microbiology of the organism and clinical manifestations of the group JK Coryneform infection. The clinical significance of this organism in the nosocomial infections of compromised patients and the association of the infection with the use of plastic devices has been emphasized. The sensitivity of the multiresistant coryneform bacterium to vancomycin may help to make the microbiological diagnosis and to select the drug for therapy.

Corynebacterium pseudotuberculosis infection in goats. VII. Clinical, pathological, serological and hematological changes after subcutaneous inoculation of the organism

Six castrated male kids from 2 herds free from caseous lymphadenitis, were inoculated subcutaneously with about 1 million colony forming units of a Corynebacterium pseudotuberculosis strain isolated from goat. The animals exhibited a febrile response and marked inflammatory reaction at the inoculation site during the first days after infection. Post mortem examination carried out 2 months after inoculation revealed abscesses in the regional lymph node (Inn. subiliaci) of all animals, in 3 of which lesions also appeared in other lymph nodes. The antibody titre (mean value) in the bacterial agglutination test peaked during the first 2 weeks following inoculation, while the titre in the hemolysis inhibition test began to rise from 2–3 weeks after the infection and continued to increase during the rest of the investigation period (9 weeks after inoculation). Hemoglobin and hematocrit levels decreased significantly after inoculation, and remained below the preinfection levels for 2 weeks. A significant leucocytosis was also seen during the same period.

The present investigation indicates that subcutaneous inoculation with C. pseudotuberculosis might be a suitable challenge system to study the efficacy of vaccines against caseous lymphadenitis in goats.

Characterization of lectin-binding lymphocytes in goats with caseous lymphadenitis

Numbers of lymphoid cells bearing markers for peanut agglutinin, wheat germ agglutinin, and anti-immunoglobulin G in healthy goats and in goats with caseous lymphadenitis were determined by use of immunofluorescent techniques. Results indicated that, when compared with healthy goats, diseased goats had normal numbers of anti-immunoglobulin G-positive cells (B cells), had significantly reduced numbers of peanut agglutinin-positive cells (T cells), and had fewer cells with receptor sites for Lens culinaris agglutinin and concanavalin A. Compared with healthy goats, numbers of peanut agglutinin-positive cells in goats with caseous lymphadenitis indicated that the goats may have had a compromised cell-mediated immunity.

[Clinical and hematological studies in experimental Corynebacterium infection in sheep]

Investigation were carried out with 24 sheep divided into groups of 12 animals each. The first group was subjected to the intrajoint infection via the lateral recess of the tarsum, using 2 cm3 of a 24-hour broth culture of Corynebacterium pyogenes for each animal, and the second one--to the i/v injection of 2 to 4 cm3 of the same broth culture. The clinical state and the morphologic changes in the blood were followed up in the course of 28 days. It was found that with such experimental suppurative surgical infection, caused by Corynebacterium pyogenes, there set in changes in the body temperature, and the pulse and respiration rates regardless of the route of infection. Both the haemoglobin and the erythrocyte count dropped, and the erythrocyte sedimentation rate rose, and the latter was found to be due to the change in the total erythrocyte count. The intrajoint infection of the sheep led the rise of the total leukocyte count, while the i/v infection lowered it. Both test groups displayed aneosinophilia, neutrophilia, lymphopenia, and rise of the monocyte count, which depended on the way of infection and its clinical course. The suppurative surgical infection caused by intrajoint introduction of these bacteria set in at a slower rate and lasted for a longer time as against the single i/v infection.

Serum proteins of normal goats and goats with caseous lymphadenitis

Values for total serum proteins and relative percentages of albumin, alpha 1-globulin, alpha 2-globulin, beta-globulin, and gamma-globulin were determined for the goat. These normal values were compared with those obtained for goats infected with Corynebacterium pseudotuberculosis. Goats chronically infected with C pseudotuberculosis show significantly higher total serum protein values than normal goats, apparently due to increased gamma-globulins. This higher protein value is also associated with a decrease in serum alpha 2- and beta-globulins.