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PubMed2007

Chemokine responses are increased in HIV-infected Malawian children with invasive pneumococcal disease.

BACKGROUND: Chemokines play an important role in the recruitment and regulation of leukocyte traffic during bacterial infection. The aims of this study were to investigate the chemokine response to invasive pneumococcal disease (IPD) and to examine the influence of HIV infection on the chemokine response, pneumococcal bacterial loads, and outcome. METHODS: We prospectively studied 95 children with IPD, and blood and cerebrospinal fluid (CSF) samples were taken at admission for the determination of chemokines, interferon-gamma (IFNgamma), and pneumococcal bacterial loads. RESULTS: Plasma CXCL8 and CCL2, CSF CXCL8 and CCL4, and IFNgamma were significantly higher in HIV-infected children than in HIV-uninfected children. Blood and CSF pneumococcal bacterial loads correlated with plasma and CSF chemokines, respectively, and were higher in HIV-infected children compared with HIV-uninfected children. Among HIV-infected children, plasma concentrations of CXCL8 and CCL2 were significantly higher in nonsurvivors than in survivors, but CCL5 was significantly lower. HIV-infected and HIV-uninfected children with IPD had higher concentrations of chemokines (except CCL5) than acutely ill HIV-infected and HIV-uninfected children with no detectable bacterial infection. Male gender and low plasma CCL2 concentrations were shown to be independently associated with survival. CONCLUSIONS: Chemokines, in particular CCL2, are associated with survival in IPD and correlate with pneumococcal bacterial loads, disease presentation, and outcome.

Adolescent↗

PubMed2006

Laboratory evaluation of the 3-bowl system used for washing-up eating utensils in the field.

OBJECTIVE: A 3-bowl system is used for washing-up eating utensils on many expeditions when running water is not available. The utensils are washed in the first bowl until they are visibly clean, rinsed in the second bowl, and disinfected in the third bowl. The objective of this study was to evaluate the efficacy of this system in reducing bacterial loads on contaminated utensils and to compare it with alternative washing-up methods. METHODS: Different washing-up systems were tested with a simulated dish washing of 5 contaminated mess tins followed by 5 uncontaminated mess tins. Porridge was used to simulate food residue and was mixed with Escherichia coli to produce bacterial contamination. Reduction of bacterial load on the mess tins was measured, as were subjective observations regarding the various systems. RESULTS: Bacterial load on contaminated tins is reduced when the 3-bowl system is used. Uncontaminated tins become contaminated in bowl 1, but this is then reduced in subsequent bowls. Disinfectant use, especially bleach, produced a marked reduction in bacterial load on contaminated and uncontaminated tins when used in bowl 2. Detergent is needed to remove grease, and a final rinse removes the smell of disinfectant. CONCLUSIONS: Overall, the most effective washing-up system in the laboratory was removal of most food residue with detergent in bowl 1, finish washing with bleach until visibly clean in bowl 2, and a final rinse in drinkable water in bowl 3. This system has advantages over the established 3-bowl system by getting mess tins clean more easily, killing potentially harmful bacteria, and removing the smell and taste of disinfectant.

Avena↗

PubMed2006

Effect of genetic background on the response to bacterial sinusitis in mice.

OBJECTIVE: To study the importance of ongoing allergen exposure and TH1/TH2 genetic background in augmented bacterial and inflammatory responses in allergic and infected mice. DESIGN: BALB/c and C57BL/6 mice were made allergic to ovalbumin. After 1 day of intranasal allergen exposure, they were inoculated intranasally with Streptococcus pneumoniae. The numbers of bacteria and inflammatory cells in the sinuses were determined, and nasal responsiveness to histamine was assessed. RESULTS: Infected BALB/c and C57BL/6 mice that received ongoing ovalbumin challenge following intraperitoneal sensitization showed significantly greater bacterial load and phagocyte level compared with the infected-only mice. Differences were diminished after the allergen challenge was stopped. Allergic and infected C57BL/6 mice showed fewer bacteria and phagocytes compared with the allergic and infected BALB/c mice. Surprisingly, in contrast to the nonallergenic C57BL/6 mice, the infected BALB/c mice showed a larger number of bacteria 28 days after infection. CONCLUSIONS: Ongoing allergic reaction augments bacterial load in both BALB/c and C57BL/6 mice and induces nasal hyperreactivity to histamine. Allergic and infected C57BL/6 mice show less allergic inflammation and bacterial load compared with allergic and infected BALB/c mice. Stopping allergen exposure reduces the response. Infected BALB/c mice, which favor a TH2 response, were less able to clear infection than C57BL/6 mice, which favor a TH1 response. Inflammation and bacterial load are affected by genetic background of mice and ongoing allergen stimulation.

Allergens↗

PubMed2001

Tongue coating and salivary bacterial counts in healthy/gingivitis subjects and periodontitis patients.

BACKGROUND: The papillary structure of the dorsum of the tongue forms a unique ecological site that provides a large surface area favoring the accumulation of oral debris and microorganisms. These micro-organisms of the tongue may be of influence on the flora of the entire oral cavity. The normal appearance of the dorsum of the tongue is either pinkish or has a thin white coating. For the present study a scoring method was developed to describe the appearance of the dorsum of the tongue in relation to the extent of color and thickness of tongue coating. AIM: The purpose of this study was to investigate the discoloration and coating of the tongue in healthy/gingivitis subjects and periodontitis patients. Furthermore, to determine the relationship between the appearance of the tongue and the bacterial load in salivary samples. MATERIAL AND METHODS: 2 groups of patients were studied, 70 healthy/gingivitis subjects and 56 periodontitis patients. After scoring of the tongue a salivary sample of each patient was taken and analyzed using a phase-contrast microscope. RESULTS: This investigation showed that most discoloration was found on the distal part of the tongue. The mean number of bacteria per ml sample in relation to a pink, white and yellow appearance of the tongue was 948, 855 and 900 (x 10(6)) respectively. The mean number of bacteria per ml sample in relation to no, thin and thick coating was 948, 863, and 895 (x 10(6)), respectively. Analysis did not reveal a relationship between discoloration, coating thickness and total bacterial load. The mean number of bacteria per ml in healthy/gingivitis subjects was 860 and in periodontitis patients 918 (x 10(6)). CONCLUSION: No relationship between the appearance of the tongue and salivary bacterial load could be detected. There was no difference in bacterial load between the healthy/gingivitis and the periodontitis group within the present study population.

Adult↗

PubMed2005

Citropin 1.1-treated central venous catheters improve the efficacy of hydrophobic antibiotics in the treatment of experimental staphylococcal catheter-related infection.

An in vitro antibiotic susceptibility assay for Staphylococcus aureus biofilms developed on 96-well polystyrene tissue culture plates was performed to elucidate the activity of citropin 1.1, rifampin and minocycline. Efficacy studies were performed in a rat model of staphylococcal CVC infection. Silastic catheters were implanted into the superior cava. Twenty-four hours after implantation the catheters were filled with citropin 1.1 (10 microg/mL). Thirty minutes later the rats were challenged via the CVC with 1.0 x 10(6) CFU of S. aureus strain Smith diffuse. Administration of antibiotics into the CVC (the antibiotic lock technique) began 24 h later. The study included: one control group (no CVC infection), one contaminated group that did not receive any antibiotic prophylaxis, one contaminated group that received citropin 1.1-treated CVC, two contaminated groups that received citropin 1.1-treated CVC plus rifampin and minocycline at concentrations equal to MBCs for adherent cells and 1024 microg/mL in a volume of 0.1 mL that filled the CVC and two contaminated groups that received rifampin or minocycline at the same concentrations. All catheters were explanted 7 days after implantation. Main outcome measures were: minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), synergy studies, quantitative culture of the biofilm formed on the catheters and surrounding venous tissues, and quantitative peripheral blood cultures. MICs of conventional antibiotics against the bacteria in a biofilm were at least four-fold higher than against the freely growing planktonic cells. In contrast, when antibiotics were used on citropin 1.1 pre-treated cells they showed comparable activity against both biofilm and planktonic organisms. The in vivo studies show that when CVCs were pre-treated with citropin 1.1 or with a high dose of antibiotics, biofilm bacterial load was reduced from 10(7) to 10(3) CFU/mL and bacteremia reduced from 10(3) to 10(1) CFU/mL. When CVCs were treated both with citropin 1.1 and antibiotics, biofilm bacterial load was further reduced to 10(1) CFU/mL and bacteremia was not detected, suggesting 100% elimination of bacteremia and a log 6 reduction in biofilm load. Citropin 1.1 significantly reduces bacterial load and enhances the effect of hydrophobic antibiotics in the treatment of CVC-associated S. aureus infections.

Amphibian Proteins↗

PubMed2002

Exacerbations of chronic obstructive pulmonary disease: when are bacteria important?

The progressive course of chronic obstructive pulmonary disease (COPD) is often aggravated by exacerbations, the majority of them produced by bronchial infection. Frequent exacerbations have been demonstrated to have a negative impact on quality of life and pulmonary function in patients with COPD, particularly in active smokers. Furthermore, acute exacerbations are the most frequent cause of medical visits, hospital admissions and death among patients with chronic lung disease. Evidence indicates that the number of patients with pathogenic bacteria in respiratory secretions and the bronchial bacterial load increase during exacerbations. Furthermore, the local inflammatory response of the host parallels the increase in bacterial load. From these observations, it can be speculated that, for symptoms of acute exacerbation to appear, there must be a minimum bacterial load in the airways, i.e. a threshold above which the inflammatory reaction is severe enough to elicit clinical symptoms of exacerbation. This threshold may vary from patient to patient owing to different modifying factors. Some of these factors may be the recognised risk factors for relapse, such as increasing age, impairment of lung function, comorbid conditions or frequent exacerbations in the past. Relapse rates after ambulatory treatment of acute exacerbation of COPD may be as high as 20-25% of cases. Relapses are associated with significant mordibity and increased costs. A number of unanswered questions remain regarding exacerbations of chronic obstructive pulmonary disease. These include the role of viral infection, the importance of residual bacterial colonisation and the impact of new antibiotics on the treatment of exacerbations.

Acute Disease↗

PubMed1998

Differential pathogenic effect of two Helicobacter-like organisms in dog gastric mucosa.

Two forms of Helicobacter were detected in the gastric mucosa of twelve healthy beagle dogs. According to ultrastructural criteria they could be classified as Helicobacter bizzozeronii-like and Helicobacter felis-like species. In five animals, the light fundic load of Helicobacter bizzozeronii-like did not affect the integrity of the glandular epithelium. In three animals, the heavy bacterial load extended in the lumens of antral glands and coincided with increased intraepithelial lymphoid infiltrate. The heavy bacterial load observed in 4 animals was mixed (Helicobacter bizzozeronii-like and Helicobacter felis-like), fundic and antral, luminal and intracellular. Adherence of Helicobacter felis-like to epithelial cells and intracellular penetration were responsible for focal necrosis, and glandular atrophy might be observed. Helicobacter bizzozeronii-like thus appeared non pathogenic in beagle dogs, even when the heavy bacterial load extended to the antrum. By contrast, Helicobacter felis-like showed a constant pathogenic effect linked to its properties of adhesion and penetration into epithelial cells. A wider comparative study in humans and domestic carnivorous will determine if the latter may play a role of reservoir-host for pathogenic bacteria.

Animals↗

PubMed2005

Lipopolysaccharide-mediated protection against Klebsiella pneumoniae-induced lobar pneumonia: intranasal vs. intramuscular route of immunization.

Immunoprotective potential of delivered lipopolysaccharide (LPS) preparation from Klebsiella pneumoniae was determined in a murine model of lobar pneumonia. Protection was assessed with three doses of LPS (25, 50 and 100 microg; without any adjuvant) administered intranasally or intramuscularly. After evaluation of lung tissue (bacterial load and histopathology), no significant protection was observed at 25 microg with either application. A significant decrease in lung bacterial load coupled with fall in severity of lung lesions was observed with 50 microg (again both applications). At 100 microg dose, with intramuscular route, a further decrease in the lung bacterial load was shown compared to the 50 microg dose. In contrast, 100 microg LPS, when given intranasally, resulted in a higher bacterial colonization of the lung tissue and higher lung pathology; thus we recommend intramuscular instead of the intranasal route for developing protection against K. pneumoniae-mediated pneumonia with intact LPS-based vaccines.

Administration, Intranasal↗

PubMed1982

The public health aspects of roast chickens sold in take-away shops in Ibadan, Nigeria.

A study is made on the bacteriological status of ready to consume roast chicken from take-away shops in Ibadan with particular emphasis on the bacterial load and identification of Salmonella app. The total viable count method using plate count agar was used to estimate the total bacterial load while the Colworth method was used to isolate and identify the Salmonella spp. Bacterial load range from 48,000 to 132,000 per gram of chicken meat. Salmonella spp. were identified in 72% of the samples examined. To protect public health, the importance of adequate thawing of deep frozen chicken prior to roasting, hygiene of utensils and meat handlers are emphasised. Proper storage and reheating of overnight stored roast chicken are necessary to prevent food poisoning from this source.

Animals↗

PubMed1994

Bacteriological studies of open versus closed contrast medium delivery systems in angiography.

The aim of this study was to evaluate the safety of the 'open' method of contrast medium delivery in the angiographic theatre, in which contrast medium is decanted into open galley pots on sterile trolleys. The air bacterial load within the angiographic theatre was sampled before and during angiographic procedures. The relationship of staff and patient activity to bacterial load was assessed. Samples of Iopromide (Ultravist 370; Schering Pty Ltd, Sydney, NSW, Australia) decanted into galley pots were taken for bacterial culture at the end of seven patient procedures. Air bacterial loads were comparable with operating theatre levels and were heaviest during staff activity. Three of seven samples taken at the end of angiographic procedures from air-exposed galley pots yielded contaminants, but the number of bacteria was below that required to produce septicaemia under normal conditions. These results suggest that the open system of contrast medium delivery can be safely used, providing that bacterial checks of room contamination are performed and personnel entry into the theatre is strictly limited.

Air Microbiology↗

PubMed2002

Chemical sympathectomy increases numbers of inflammatory cells in the peritoneum early in murine listeriosis.

Here, we investigated the effects of sympathectomy on systemic bacterial loads following infection with Listeria monocytogenes, and on innate and specific immune responses in the peritoneum. Sympathectomy decreased systemic bacterial loads, and increased the number of peritoneal leukocytes and the percentage of peritoneal macrophages three days postinfection. This suggests that sympathectomy-induced decreases systemic bacterial loads are associated with increased recruitment of inflammatory cells into tissues during the innate immune response.

Animals↗

PubMed2001

Induction of multiple chemokine and colony-stimulating factor genes in experimental Burkholderia pseudomallei infection.

Melioidosis is a disease of the tropics caused by the facultative intracellular bacterium Burkholderia pseudomallei. In human infection, increased levels of IFN-gamma in addition to the chemokines interferon-gamma-inducible protein 10 (IP-10) and monocyte interferon-gamma-inducible protein (Mig) have been demonstrated. However, the role of these and other chemokines in the pathogenesis of melioidosis remains unknown. Using BALB/c and C57BL/6 mice as models of the acute and chronic forms of human melioidosis, the induction of mRNA was assessed for various chemokines and CSF (G-CSF, M-CSF, GM-CSF, IP-10, Mig, RANTES, MCP-1, KC and MIP-2) in spleen and liver following B. pseudomallei infection. Patterns of chemokine and CSF induction were similar in liver and spleen; however, responses were typically greater in spleen, which reflected higher tissue bacterial loads. In BALB/c mice, high-level expression of mRNA for all chemokines and CSF investigated was demonstrated at day 3 postinfection, correlating with peak bacterial load and extensive infiltration of leucocytes. In contrast, increased mRNA expression and bacterial numbers in C57BL/6 mice were greatest between 4 and 14 days following infection. This paralleled increases in the size and number of abscesses in liver and spleen of C57BL/6 mice at days 3 and 14 postinfection. Earlier induction of cytokine-induced neutrophil chemoattractant (KC), macrophage inflammatory protein-2 (MIP-2), monocyte chemoattractant protein-1 (MCP-1), granulocyte-macrophage CSF (GM-CSF) and macrophage CSF (M-CSF) mRNA was demonstrated in spleen, while MIP-2, MCP-1, IP-10 and Mig were demonstrated in liver of BALB/c mice when compared to spleen and liver of C57BL/6. The magnitude of cellular responses observed in the tissue correlated with increased levels of the chemokines and CSF investigated, as well as bacterial load. Compared with C57BL/6 mice, greater infiltration of neutrophils was observed in liver and spleen of BALB/c mice at day 3. In contrast, early lesions in C57BL/6 mice predominantly comprised macrophages. These results suggest that the inability of BALB/c mice to contain the infection at sites of inflammation may underlie the susceptible phenotype of this mouse strain towards B. pseudomallei infection.

Animals↗

PubMed2001

Comparative study of treatment with penicillin, ceftriaxone, trovafloxacin, quinupristin-dalfopristin and vancomycin in experimental endocarditis due to penicillin- and ceftriaxone-resistant Streptococcus pneumoniae.

The efficacy of different antibiotics was compared in an experimental model of aortic valve endocarditis in rabbits, using a serotype 19 strain of Streptococcus pneumoniae resistant to penicillin (MIC 12 mg/L) and ceftriaxone (MIC 12 mg/L). The results were compared with those of a control group, which received no treatment. One hundred and nineteen animals were treated with one of the following antibiotic regimens: im procaine penicillin G at a dosage of 300,000 U/kg weight/12 h (16 animals); iv trovafloxacin, 13.3 mg/kg/12 h (31 animals); iv ceftriaxone, 75 mg/kg/24 h (21 animals); iv vancomycin, 20 mg/kg/12 h (15 animals) and im quinupristin-dalfopristin, 30 mg/kg/8 h (20 animals). All the antibiotics used in this study proved to be efficient in reducing numbers of S. pneumoniae and in increasing the percentage of aortic vegetations that were rendered sterile compared with the control group. Penicillin at the dosage used in our study was capable of achieving serum concentrations two or three times greater than the MIC, thus demonstrating its effectiveness as an antibiotic for this endocarditis model. No significant difference was observed between the effects of vancomycin, quinupristin-dalfopristin and penicillin. Vancomycin proved to be more efficient than trovofloxacin in reducing the bacterial load and increasing the numbers sterilized. There was also a tendency for this antibiotic to be more effective than ceftriaxone in reducing the bacterial load of the vegetations. There was a statistically significant correlation between the weight of the vegetations and their bacterial load. In the light of these results, vancomycin and quinupristin-dalfopristin may be considered suitable alternatives to penicillin for the treatment of penicillin-resistant S. pneumoniae endocarditis.

Animals↗

PubMed2006

[Immune response and protective efficacy induced by fusion protein ESAT6-CFP10 of M.tuberculosis in mice].

AIM: To study murine humoral and cellular immune response induced by fusion protein ESAT6-CFP10 and to examine its protective efficacy against M. tuberculosis (MTB) in mice. METHODS: BALB/c mice were immunized subcutaneously on the back with fusion protein ESAT6-CFP10 that was transferred to nitro cellulose (NC) membrane beforehand. Stimulation index (SI) of the spleen lymphocytes of the immunized mice was measured by MTT colorimetry. The level of IFN-gamma and IL-2 and CTL upon antigen-specific stimulation were detected. The vaccinated BALB/c mice were intravenously infected with MTB H37Rv (10(5) CFU/mouse). Four weeks later the number of CFU in spleens was determined. RESULTS: The titer of serum specific antibody in BALB/c mice immunized with fusion protein ESAT6-CFP10 was 1:6,400. The SI of fusion protein immunized group (1.90+/-0.15) was significantly higher than that of saline-immunized group (0.9+/-0.15). The level of IFN-gamma and IL-2 induced by the fusion protein was 1.792+/-19 ng/L and 0.211+/-11 ng/L respectively, which was significantly higher than that of saline-immunized group and lower than that of BCG-immunized group. The specific killing activity of splenocytes was 36%. Compared with the saline-immunized mice (bacterial load was 6.51+/-0.13), MTB number (bacterial load was 5.24+/-0.15) was reduced dramatically in the spleens of BALB/c mice immunized with the fusion protein, but the protective efficacy of the mice immunized with BCG was higher than that of ESAT6-CFP10 vaccinated group. CONCLUSION: Fusion protein ESAT6-CFP10 can be used as a candidate for novel vaccines.

Animals↗

PubMed2002

IL-18 contributes to host resistance against infection with Pseudomonas aeruginosa through induction of IFN-gamma production.

Pseudomonas aeruginosa keratitis destroys the cornea in susceptible (B6), but not resistant (BALB/c) mice. To determine mechanisms mediating resistance, the role of IFN-gamma, IL-12, and IL-18 was tested in BALB/c mice. RT-PCR analysis detected IFN-gamma mRNA expression levels in cornea that were significantly increased at 1-7 days postinfection. IL-18 mRNA was detected constitutively in cornea and, at 1-7 days postinfection, levels were elevated significantly, while no IL-12 mRNA was similarly detected. To test whether IL-18 contributed to IFN-gamma production, mice were treated with anti-IL-18 mAb. Treatment decreased corneal IFN-gamma mRNA levels, and bacterial load and disease increased/worsened, compared with IgG-treated mice. To stringently examine the role of IFN-gamma in bacterial killing, knockout (-/-) vs wild-type (wt) mice also were tested. All corneas perforated, and bacterial load was increased significantly in -/- vs wt mice. Because disease severity was increased in IFN-gamma(-/-) vs IL-18-neutralized mice, and since IL-18 also induces production of TNF, we tested for TNF-alpha in both groups. ELISA analysis demonstrated significantly elevated corneal TNF-alpha protein levels in IFN-gamma(-/-) vs wt mice after infection. In contrast, RT-PCR analysis of IL-18-neutralized vs IgG-treated infected mice revealed decreased corneal TNF-alpha mRNA expression. Next, to resolve whether TNF was required for bacterial killing, TNF-alpha was neutralized in BALB/c mice. No difference in corneal bacterial load was detected in neutralized vs IgG-treated mice. These data provide evidence that IL-18 contributes to the resistance response by induction of IFN-gamma and that IFN-gamma is required for bacterial killing.

Animals↗

PubMed1989

T-cell-mediated protection of mice against virulent Mycobacterium tuberculosis.

We sought to protect CBA mice against tuberculosis using in vivo transfer of a T-cell line previously shown to be capable of I-A-restricted recognition of peritoneal macrophages infected in vitro with Mycobacterium tuberculosis. This line induces total bacteriostasis in vitro. In mice that received 500 rads of irradiation 48 h before infection, the T-cell line caused significant prolongation of life when given intravenously with a challenge dose of 5 x 10(6) organisms. Similar experiments with two other T-cell lines showed that these lines offered no protection. Bacterial load at the time of death was inversely related to the time of survival. Thus, death occurred at a lower bacterial load in adoptively protected mice, implying the contribution of an immunopathological component in these animals. The protective T-cell line, which was CD4+ CD8-, had no effect on the rate of growth of strain BCG in CBA nu/nu mice or M. tuberculosis in fully T-cell-deprived mice. This could indicate that CD8+ cells play a role in this system or that there is a need for the recruitment of interleukin 2-producing cells in the recipient. Experiments with monoclonal antibodies to selectively deplete T-cell subsets in normal CBA mice showed that depletion of CD4+ cells strikingly shortened survival, whereas depletion of CD8+ cells did not. However, CD8-depleted mice died with a lower bacterial load than those found in nondepleted controls, and the lesions in CD8-depleted mice were histopathologically distinct. These results suggest that the CD8+ cells either down-regulate bacteriostasis or cause immunopathology in this model and that it is the CD4+ cells that are the major protective subset in long-term protection experiments.

Animals↗

PubMed2003

Vaccine-induced reduction of Helicobacter pylori colonization in mice is interleukin-12 dependent but gamma interferon and inducible nitric oxide synthase independent.

Previous studies with mice have shown that major histocompatibility complex class II (MHC-II) is required for protection from Helicobacter pylori, while MHC-I and antibodies are not. Thus, CD4(+) T cells are presumed to play an essential role in protective immunity via secretion of cytokines. To determine which cytokines are associated with a reduction of bacterial load in immunized mice, gastric cytokine expression was examined by semiquantitative reverse transcription-PCR in protected (defined as > or =2-log-unit decrease in bacterial load) and unprotected mice 4 weeks after challenge. Elevated levels of mRNA for interleukin-12p40 (IL-12p40), gamma interferon (IFN-gamma), tumor necrosis factor alpha, and inducible nitric oxide synthase (iNOS) were associated with protection in immunized-challenged (I/C) mice, but Th2 cytokine (IL-4, IL-5, IL-10, and IL-13) and chemokine (KC, MIP-2, and MCP-1) expression was not associated with protection. Despite the association of IFN-gamma and iNOS message with protection, I/C mice genetically lacking either of these products were able to reduce the bacterial load as well as the wild-type I/C controls. The I/C mice lacking IL-12p40 were not protected compared to unimmunized-challenged mice. All I/C groups developed gastritis. We conclude that neither IFN-gamma nor iNOS is essential for vaccine-induced protection from H. pylori infection. The p40 subunit of IL-12, which is a component of both IL-12 and IL-23, is necessary for protection in immunized mice. These findings suggest a novel IFN-gamma-independent function of IL-12p40 in effective mucosal immunization against H. pylori.

Administration, Intranasal↗

PubMed2026

High within-herd prevalence and assessment of production impacts of Coxiella burnetii in postpartum cattle from a Scottish dairy herd.

Coxiella burnetii is endemic in Great Britain dairy herds but detailed investigations of C. burnetii epidemiology and impacts on livestock production in this region are scarce. The objectives of this cross-sectional study were to first determine the within-herd prevalence of C. burnetii on a commercial Scottish dairy farm with prior detection of C. burnetii and second assess the relationship between pathogen load and individual health and performance traits. Vaginal swabs were collected from cows up to seven days postpartum. DNA extracts were tested for C. burnetii by IS1111 qPCR assay. Generalized linear models were used to estimate the relationships between bacterial load and health and performance traits. A total of 313 swabs were collected between 15 December 2022 and 06 July 2023, of which 301 (96.1%) had detectable C. burnetii DNA with Ct ≤ 40. The Ct values observed (12.9-38.7) corresponded to estimated genome equivalents per reaction of < 1 to ∼2.5 million genomes. Higher bacterial loads were seen in primiparous compared to multiparous cows. Higher bacterial loads were also more likely in cows that had experienced one or more negative reproductive outcomes, including abortion, premature delivery, prolonged gestation, stillbirth and dystocia. The direction of causation underlying the observed associations and representativeness of findings from this single herd require further investigation. This study provides insights into the within-herd dynamics of C. burnetii and evidence generated through sampling and diagnostic testing approaches that can inform future work to characterize the epidemiology and impacts of this infection in Great Britain dairy cattle and globally.

Cattle↗