Detection of Salmonella Enteritidis (SE) bacterin in environmental samples from poultry houses using the RapidChek SE immunoassay

Environmental swabs from pullet houses were tested for the presence of Salmonella Enteritidis (SE) using the RapidChek SE immunoassay test. Of the 1162 samples tested in 2011, 20 samples were positive, but only two samples were confirmed positive for SE by culture. Seventeen positive samples were from pullet houses that had been vaccinated with SE bacterin 2 to 3 days prior to submission to the lab. This study investigated the detection of SE bacterin using the RapidChek SE test system. Swabs were inoculated with different amounts of a commercial SE bacterin. As little as 0.25 ml of the SE bacterin was sufficient to cause positive results with the RapidChek SE test. This finding emphasizes the need to perform bacterial isolation and identification when a positive result occurs using an immunoassay test.

Pathogenicity of Salmonella enteritidis phage types 4, 8 and 23 in specific pathogen free chicks

The pathogenicity of two isolates of Salmonella enterica serovar Enteritidis (SE) phage type (PT) 4, three of PT8 and one of PT23 was investigated in groups of 1-day-old specific pathogen free White Leghorn chicks. Two groups were crop gavaged with each culture but at two different doses. Two additional groups were given Salmonella enterica serovar Pullorum (SP) at similar doses and one further group served as uninoculated controls. Body weights were recorded at 14, 21, and 28 days postinoculation (d.p.i), and mortality was monitored throughout. In most treatment groups, the average body weights were significantly lower than the controls. Birds inoculated with SP had the highest mortality followed by those given SE PT4 of human or chicken origin. At 14 and 21 d.p.i., four chicks from each group were killed and examined for gross lesions. Selected tissues were collected for histopathology and cultured for bacteria. Dead birds had fibrinous exudate in the pericardium and also, in a few, on the liver capsule. They had enlarged livers, sometimes with congestion and white foci. At 7 d.p.i., several birds, especially those inoculated with SE PT4, had retained yolk sacs containing coagulated material. Microscopic lesions of pericarditis, myocarditis, hepatitis, splenitis, peritonitis and enteritis were present at 7 d.p.i. in most birds inoculated with SE, but was greatly variable at 14 d.p.i.. This study shows that 1-day-old SPF chicks are susceptible to various phage types of SE, with yolk-sac infection as the most prominent feature.

Evaluation of human immunodeficiency virus and hepatitis C telemedicine clinics

BACKGROUND

Geographical barriers to subspecialty care may prevent optimal care of patients living in rural areas. We assess the impact of human immunodeficiency virus (HIV) and hepatitis C telemedicine consultation on patient-oriented outcomes in a rural Veterans Affairs population.

METHODS

This was a pre- and post-intervention study comparing telemedicine with in-person subspecialty clinic visits for HIV and hepatitis C. Eligible patients resided in 2 rural catchment areas. The primary binary outcome was clinic completion. We estimated a logistic regression model with patient-level fixed effects. This approach controls for the clustering of visits by patient, uses each patient's in-person clinic experience as an internal control group, and eliminates confounding by person-level factors. We also surveyed patients to assess satisfaction and patient-perceived reductions in health visit-related time.

RESULTS

There were 43 patients who accounted for 94 telemedicine visits and 128 in-person visits. Clinic completion rates were higher for telemedicine (76%) than for in-person visits (61%). In regression analyses, telemedicine was strongly predictive of clinic completion (OR 2.2; 95% confidence interval [CI]: 1.0-4.7). The adjusted effect of telemedicine on clinic completion rate was 13% (95% CI: 12-13). Of the 30 patients (70%) who completed the survey, more than 95% rated telemedicine at the highest level of satisfaction and preferred telemedicine to in-person clinic visits. Patients reported a significant reduction in health visit-related time (median 340 minutes, interquartile range 250-440), mostly due to decreased travel time.

CONCLUSIONS

HIV and hepatitis C telemedicine clinics are associated with improved access, high patient satisfaction, and reduction in health visit-related time.

Induction of multiple matrix metalloproteinases in human dermal and synovial fibroblasts by Staphylococcus aureus: implications in the pathogenesis of septic arthritis and other soft tissue infections

Infections of body tissue by Staphylococcus aureus are quickly followed by degradation of connective tissue. Patients with rheumatoid arthritis are more prone to S. aureus-mediated septic arthritis. Various types of collagen form the major structural matrix of different connective tissues of the body. These different collagens are degraded by specific matrix metalloproteinases (MMPs) produced by fibroblasts, other connective tissue cells, and inflammatory cells that are induced by interleukin-1 (IL-1) and tumor necrosis factor (TNF). To determine the host's contribution in the joint destruction of S. aureus-mediated septic arthritis, we analyzed the MMP expression profile in human dermal and synovial fibroblasts upon exposure to culture supernatant and whole cell lysates of S. aureus. Human dermal and synovial fibroblasts treated with cell lysate and filtered culture supernatants had significantly enhanced expression of MMP-1, MMP-2, MMP-3, MMP-7, MMP-10, and MMP-11 compared with the untreated controls (p < 0.05). In the S. aureus culture supernatant, the MMP induction activity was identified to be within the molecular-weight range of 30 to >50 kDa. The MMP expression profile was similar in fibroblasts exposed to a combination of IL-1/TNF. mRNA levels of several genes of the mitogen-activated protein kinase (MAPK) signal transduction pathway were significantly elevated in fibroblasts treated with S. aureus cell lysate and culture supernatant. Also, tyrosine phosphorylation was significantly higher in fibroblasts treated with S. aureus components. Tyrosine phosphorylation and MAPK gene expression patterns were similar in fibroblasts treated with a combination of IL-1/TNF and S. aureus. Mutants lacking staphylococcal accessory regulator (Sar) and accessory gene regulator (Agr), which cause significantly less severe septic arthritis in murine models, were able to induce expression of several MMP mRNA comparable with that of their isogenic parent strain but induced notably higher levels of tissue inhibitors of metalloproteinases (TIMPs). To our knowledge, this is the first report of induction of multiple MMP/TIMP expression from human dermal and synovial fibroblasts upon S. aureus treatment. We propose that host-derived MMPs contribute to the progressive joint destruction observed in S. aureus-mediated septic arthritis.

Trimethoprim-Sulfamethoxazole Associated Rhabdomyolysis in a Patient with AIDS: Case Report and Review of the Literature

We report a case of rhabdomyolysis associated with the use of trimethoprim-sulfamethoxazole (TMP-SMX) in a newly diagnosed AIDS patient with presumed Pneumocystis jiroveci (formerly named Pneumocystis Carinii) pneumonia. The present case is significant because of the paucity of similar cases in the literature and the relative frequency with which TMP-SMX is used today.

Campylobacter jejuni infection in broiler chickens

Day-old, straight-run broiler chickens were procured from a hatchery located in the Pacific Northwest. The chickens were subdivided individually into nine groups of 20 chickens. The chickens were tagged, housed in isolation chambers on wire, fed commercial broiler feed, and given water ad libitum. Three isolates of Campylobacter jejuni of poultry origin and one of human origin were tested in this study. Various C. jejuni cultures were inoculated into 9-day-old chickens by crop gavage. Four groups of 20 chickens were inoculated at a dose level of 0.5 ml of 1 x 10(2) colony-forming units (CFU)/ml. The other four groups were inoculated with 0.5 ml of 1 X 10(4) CFU/ml. One group of 20 chickens was kept as an uninoculated control group. Four randomly selected chickens from each of the inoculated and uninoculated groups were necropsied at 5, 12, and 19 days postinoculation (DPI). The C. jejuni was cultured and enumerated from a composite of the upper and midintestine and the cecum. Body weights of all chicken groups at 7 days of age and at 5, 12, and 19 DPI were measured and statistically analyzed. No significant differences were present in the mean body weights (MBWs) of 7-day-old, 5 DPI, and 12 DPI male and female broiler chickens inoculated with C. jejuni at both dose levels compared with uninoculated controls. Differences in MBWs of the male and female broilers at 19 DPI were observed in some of the groups. Results of the C. jejuni culture enumeration mean (CEM) of composite intestine samples at 5 DPI from all inoculated chicken groups, irrespective of the dose level, ranged from (2.5 +/- 5.0) x 10(2) to (2.8 +/- 4.8) x 10(5) CFU/g (mean +/- SD). Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. CEM results from the composite intestine samples at 12 and 19 DPI increased by 1 log unit, or sometimes more. Results of cecum C. jejuni CEM at 5 DPI inoculated at both dose levels ranged from (2.5 +/- 5.0) x 10(6) to (1 +/- 0.0) x 10(7) CFU/g in all treatment groups irrespective of the dose level. Increases of 2-5 log units in C. jejuni CEM was present in chicken groups inoculated with 1 X 10(2) CFU of C. jejuni, and a 2- to 3-log increase was present in groups inoculated with a higher dose level of C. jejuni at 12 DPI. The results of C. jejuni CEM from cecal samples at 19 DPI were similar to chicken groups at 12 DPI. Campylobacterjejuni was not isolated from the uninoculated control chickens at 5, 12, and 19 DPI. Clinical signs of illness or gross pathologic lesions were not present in any of the chicken groups during this study. No lesions were present on histopathologic evaluations in C. jejuni-inoculated chickens or uninoculated control chickens.

High Mortality in Egg Layers as a Result of Necrotic Enteritis

A new facility was designed to hold 1.8 million birds in 10 houses; chickens were placed in five of the houses, and the remaining five houses were under construction when this outbreak occurred. An increase in mortality was reported in five houses; however, mortality in house 7 was quite high. Well-fleshed birds were suddenly found dead without a significant drop in egg production. The middle and distal intestines were distended with gas, congested, thin walled, atonic, and bluish or pale in color with sloughed mucosa in some places. Necrotic enteritis was diagnosed as the cause of increased mortality. The ingesta in the crop occasionally contained flies. The 4-wk mortality in house 7 was 6.55% with a loss of 10,898 chickens. The 4-wk mortality rate in the other houses ranged from 0.54% to 1.98%. The houses affected with necrotic enteritis were treated for coccidiosis with amprolium because low numbers of the oocysts were present in the intestinal specimens of some of the chickens. Household bleach was added to the water at a dilution of one part bleach to 1040 parts water to control bacterial contamination. The fly (Musca domestica) population was out of control. Clostridium perfringens was isolated from the alcohol-washed macerated flies caught from houses 4 and 7. Dead flies were often seen in the feed troughs. The chickens may possibly have had C. perfringens infection as a result of consumption of dead flies or their secretions/excretions. The alcohol-washed, macerated, clarified fly extract from the affected houses caused death in 11 inoculated mice and paralysis in one mouse. Similarly, illness and mortality were present in four mice inoculated with clarified intestinal contents. The bacterium isolated on anaerobic culture was identified as C. perfringens by polymerase chain reaction. The disease was brought under control after straw was added and mixed in with the litter. As a result, the litter temperature increased, causing a decrease in the fly population. This study suggests that flies in the poultry houses acted as mechanical transmitters of C. perfringens and that the development of necrotic enteritis was by ingestion of bacteria present in the flies and their secretions/excretions.

Pathogenicity of environmental origin Salmonellas in specific pathogen-free chicks

Two hundred sixty 1-d-old specific pathogen-free (SPF), Single Comb White Leghorn chicks were used in this study to determine pathology caused by Salmonella enteritidis (SE) isolated from a poultry environment. The chicks were subdivided into 10 equal groups of 26 chicks each. Eight groups of chicks were inoculated individually with 0.5 mL of brain heart infusion broth culture containing 1 x 10(6) cfu of SE phage type (PT) -8 (1, 2, 3), SE PT5 A (1, 2), or SE PT4 (Ch-env-CA, chicken-CA, and human) by crop gavage. One group of 26 chicks were inoculated with 1 x 10(6) cfu of Salmonella pullorum per bird by crop gavage. Another group of 26 chicks were kept as an uninoculated control group. All the chicks were observed daily for clinical signs and mortality. Salmonella was reisolated from different organs at 7, 14, 21, and 28 postinoculation (DPI). All of the chicks were weighed individually at each interval. Two chicks at random from each group were euthanised and necropsied at each DPI for gross pathology. Selected tissues were examined for histopathological changes at 7 and 14 DPI. Dead chicks were examined for gross and histopathological lesions. Mortality rates were 30.7, 15.3, and 7.6% in the groups inoculated with S. pullorum, SE PT5A, and SE PT4 (chicken-CA), respectively. No mortality or clinical sign were observed in other treatment groups or in uninoculated control groups. Cecal pouches were found to be the ideal organ for reisolation of Salmlonella at acute or chronic infection compared with other organs. Mean body weights were reduced to 1.8 to 12.6% in inoculated groups compared with the uninoculated control group. The consistent gross and hispathological lesions were of peritonitis, perihepatitis, yolk sac infection, and enteritis. Subclinical Salmlonella infection identified in this study resulted in reduced body weights of inoculated birds compared with uninoculated controls.

Enhanced extracellular growth of Staphylococcus aureus in the presence of selected linear peptide fragments of human interleukin (IL)-1beta and IL-1 receptor antagonist

Replication of Staphylococcus aureus is significantly enhanced in the presence of recombinant interleukin (IL)-1beta. In this study, specific binding of IL-1beta to the surface of S. aureus significantly increased growth of S. aureus in the presence of IL-1beta and IL-1ra in a concentration-dependent manner. Although IL-1ra enhanced the growth of S. aureus, there was a significant reduction in IL-1beta-mediated growth enhancement of S. aureus when 25-fold excess amounts of IL-1ra (in comparison with the IL-1beta concentration) were present in the culture medium. Thus, IL-1beta may influence the growth of S. aureus through a receptor-mediated event. By using 5 linear peptides spanning limited regions of IL-1beta, the growth-promoting regions were localized to amino acid residues 118-147 and 208-240. These results build on the newly evolved concept of direct interactions between the soluble mediators of inflammation and infectious agents.

Cytokines IL-1beta, IL-6, and TNF-alpha enhance in vitro growth of bacteria

We have previously reported that in acute respiratory distress syndrome (ARDS), nonsurvivors have persistent elevation in pulmonary and circulating proinflammatory cytokine levels over time and a high rate of nosocomial infections antemortem. In these patients, none of the proven or suspected nosocomial infections caused a transient or sustained increase in plasma proinflammatory cytokine levels above preinfection values. We hypothesized that cytokines secreted by the host during ARDS may favor the growth of bacteria. We conducted an in vitro study of the growth of three bacteria clinically relevant in nosocomial infections, evaluating their in vitro response to various concentrations of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6. We found that all three bacterial species showed concentration-dependent growth enhancement when incubated with one or more tested cytokines and that blockade by specific neutralizing cytokine MoAb significantly inhibited cytokine-induced growth. When compared with control, the 6-h growth response (cfu/ml) was maximal with IL-1beta at 1,000 pg for Staphylococcus aureus (36 +/- 16 versus 377 +/- 16; p = 0.0001) and Acinetobacter spp. (317 +/- 1,147 versus 1,124 +/- 147; p = 0.002) and with IL-6 at 1,000 pg for Pseudomonas aeruginosa (99 +/- 50 versus 509 +/- 50; p = 0.009). The effects of cytokines were seen only with fresh isolates and were lost with passage in vitro on bacteriologic medium without added cytokines. In this study we provide additional evidence for a newly described pathogenetic mechanism for bacterial proliferation in the presence of exaggerated and protracted inflammation.

Pathogenicity of Salmonella enteritidis phage types 4, 8, and 23 in broiler chicks

Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each. Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage. Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE. One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S. pullorum. A group of 30 chicks were kept as uninoculated controls. Chicks were observed daily for clinical signs and mortality. All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI). Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI. Gross lesions were recorded and selected tissues were collected for histopathology. The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S. pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin. Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23. Variable mortality was evident in groups inoculated with the lower dose of salmonella. The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups. The lower mean body weights were present in all treatment groups compared with uninoculated controls. No illness or mortality was observed in uninoculated control groups.

Oral staphylococcus in older subjects with rheumatoid arthritis

OBJECTIVE

To determine if Staphylococcus aureus and Staphylococcus epidermidis, etiologic bacterial agents to late prosthetic joint infections (LPJI), are more prevalent in the oral flora of older individuals with rheumatoid arthritis (RA) than in an age and gender-matched nonarthritic control population (NA).

DESIGN

Cultures were obtained from the nares, oropharynx, saliva, tongue, and gingival crevice, and the results were compared between older patients with RA and controls.

SETTING

University of Michigan Medical Center, Ann Arbor, VA Medical Center, and University of Michigan School of Dentistry.

PARTICIPANTS

A total of 111 community-dwelling subjects with a diagnosis of RA and 83 gender-matched control subjects.

MEASUREMENTS

Colistin nalidixic acid agar plates with 5% sheep's blood were inoculated and incubated. Isolates were speciated using the API Staph Trac micro method and catalase and coagulase tests.

MAIN RESULTS

Individuals with RA had a higher prevalence of S. aureus isolated from the oral cavity. However, only the oropharynx and tongue revealed higher rates; all other sites were insignificant. The presence of oral S. aureus was associated with xerostomia. Staphylococcus epidermidis was not detected from any of the oral sites sampled. Sixty-two percent (10/16) of the S. aureus isolates from the RA subjects were resistant to penicillin and ampicillin, whereas none were resistant to a cephalosporin.

CONCLUSIONS

These findings suggest that rheumatoid arthritis may be a risk factor for LPJI in older prosthetic joint patients undergoing invasive dental procedure in the posterior oral cavity. This increased risk is caused, in part, by a higher prevalence of S. aureus in the posterior oral cavity. The prevalence and the antibiotic resistance of S. aureus must be considered when determining the need for chemoprophylaxis.

The epidemiology of enterococci

The enterococci are emerging as a significant cause of nosocomial infections, accounting for approximately 10% of hospital acquired infections. They are found as normal inhabitants of the human gastrointestinal tract, but may also colonize the oropharynx, vagina, perineal region and soft tissue wounds of asymptomatic patients. Until recently, evidence indicated that most enterococcal infections arose from patients' own endogenous flora. Recent studies, however, suggest that exogenous acquisition may occur and that person-to-person spread, probably on the hands of medical personnel, may be a significant mode of transmission of resistant enterococci within the hospital. The use of broad-spectrum antibiotics, especially cephalosporins, is another major factor in the increasing incidence of enterococcal infections. These findings suggest that barrier precautions, as applied with other resistant nosocomial pathogens, along with more judicial use of antibiotics may be beneficial in preventing nosocomial spread of resistant enterococci.

Clostridium difficile plasmid isolation as an epidemiologic tool

A large hospital outbreak of Clostridium difficile diarrhea at the Minneapolis Veterans Administration Medical Center (MVAMC) was studied by plasmid profile typing. Plasmids were obtained from 30 (37%) of 82 clinical isolates from MVAMC patients and 10 (67%) of 15 non-MVAMC isolates. While bacteriophage plus bacteriocin typing and polyacrylamide gel electrophoresis (PAGE) plus bacterial agglutination typing proved more universally applicable, plasmid profiles may be useful for tracing isolated epidemic outbreaks, reinfections and relapses caused by plasmid-bearing strains.

In-vitro activity of Sch 34343 against nosocomial pathogens: methicillin-resistant staphylococci, gentamicin-susceptible and -resistant Streptococcus faecalis, Clostridium difficile and Bacteroides fragilis

The in-vitro activity of Sch 34343, a new beta-lactam antimicrobial, was studied in vitro by quantitative broth dilution methods. It was found to have good antibacterial activity against four emerging problem pathogens: methicillin-resistant Staphylococcus aureus, Streptococcus faecalis isolates showing high level resistance to gentamicin (and other aminoglycosides), Clostridium difficile (the cause of pseudomembranous colitis), and Bacteroides fragilis. On the basis of these promising results, Sch 34343 merits further in-vitro and in-vivo study to define its potential usefulness in treatment of infections with these pathogens in humans.

Epidemic Shiga bacillus dysentery in Central Africa

An outbreak of dysentery began late in 1979 in Central Africa and spread to involve a major portion of Zaire as well as Rwanda and Burundi. We traveled to a mission hospital in northeast Zaire during the epidemic and isolated Shigella dysenteriae, type 1, from most of the patients studied. All isolates were resistant to ampicillin, tetracycline, chloramphenicol, sulfathiazole, and streptomycin but sensitive to trimethoprim-sulfamethoxazole. Antimicrobial resistance was transferable to Escherichia coli, and at least three plasmids were identified in the donor Shigella isolates by using agarose gel electrophoresis. One was coded for ampicillin, tetracycline, and chloramphenicol resistance while a second conferred resistance to ampicillin and chloramphenicol but not tetracycline. A third large plasmid of approximately 120 megadaltons could not be transferred to E. coli recipients. All S. dysenteriae isolates yielded identical kinetic growth curves when analyzed on the Abbot MS-2 Research System. This is the most extensive outbreak of dysentery caused by S. dysenteriae reported since the Central American epidemic of 1969, and the first epidemic caused by a strain resistant to ampicillin.

Effects of subinhibitory antibiotics on bactericidal activity of chronic granulomatous disease granulocytes in vitro

Experiments were performed on leukocytes from patients with chronic granulomatous disease (CGD), incubated with subinhibitory concentrations of antibiotics (clindamycin, methicillin and N-demethyl-lincomycin). Results indicate a minor enhancement of bactericidal activity. This improvement occurred in both CGD homozygotes and one heterozygote and may indicate a future role for the use of low dose antibiotics to augment immune defences such as granulocyte function.

Epidemic occurrence of neonatal necrotizing enterocolitis

In case-control studies of three epidemics of neonatal necrotizing enterocolitis (NEC) in three different high-risk nurseries in three states, no particular risk factor was associated with affected infants or their mothers. Epidemic cases had higher birth weights and Apgar scores and fewer perinatal difficulties than those previously reported for sporadic cases. Seven infants fed primarily breast milk were not protected against disease. Early antibiotic therapy was associated with a significantly decreased risk of disease in one outbreak. In two hospitals, affected infants who received antibiotic therapy during the first three days of life had a significantly later disease onset. The occurrence of the disease in epidemics and the decreased risk or modification of disease with antibiotic therapy support an infectious etiology for NEC.

Inhibitory effect of heparin on gentamicin concentrations in blood

In monitoring gentamicin concentrations in the blood of patients with renal insufficiency, the assayed antibiotic concentration was found to be lower when the sample was drawn as heparinized plasma rather than as serum. This lowering of gentamicin concentrations by heparin was studied further by adding increasing doses of heparin and various amounts of gentamicin to human serum. With a range of 2 to 100 units of heparin per ml, gentamicin concentrations in the serum were lowered by 9 to 14%; with higher heparin concentrations, an even greater and increasing inhibition was noticed, reaching 56% for 1,000 units/ml. This inhibitory effect of heparin on gentamicin was reversible by dilution, indicating that it was not due to degradation or to formation of an inactive chemical complex. Underestimation by the laboratory of gentamicin concentrations in blood is likely to be greatest with capillary tubes, with which the concentration of heparin is especially high. With clinical heparinization, the amount of active heparin in the blood does not exceed 10 units/ml and is for the most part under 3 units/ml; thus, therapeutically significant inhibition of the antibiotic is unlikely in patients receiving anticoagulation.