scholarly journals Inactivation Kinetics of Coxiella burnetii During High-Temperature Short-Time Pasteurization of Milk

2022 ◽  
Vol 12 ◽  
Author(s):  
Marcel Wittwer ◽  
Philipp Hammer ◽  
Martin Runge ◽  
Peter Valentin-Weigand ◽  
Heinrich Neubauer ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Q Fever ◽  
Bacterial Pathogen ◽  
Raw Milk ◽  
High Heat ◽  
Inactivation Kinetics ◽  
Causative Organism ◽  
Codex Alimentarius ◽  
High Temperature Short Time ◽  
Heat Treated

The Gram-negative, obligate intracellular bacterium Coxiella burnetii is the causative organism of the zoonosis Q fever and is known for its resistance toward various intra- and extracellular stressors. Infected ruminants such as cattle, sheep, and goats can shed the pathogen in their milk. Pasteurization of raw milk was introduced for the inactivation of C. burnetii and other milk-borne pathogens. Legal regulations for the pasteurization of milk are mostly based on recommendations of the Codex Alimentarius. As described there, C. burnetii is considered as the most heat-resistant non-spore-forming bacterial pathogen in milk and has to be reduced by at least 5 log10-steps during the pasteurization process. However, the corresponding inactivation data for C. burnetii originate from experiments performed more than 60 years ago. Recent scientific findings and the technological progress of modern pasteurization equipment indicate that C. burnetii is potentially more effectively inactivated during pasteurization than demanded in the Codex Alimentarius. In the present study, ultra-high heat-treated milk was inoculated with different C. burnetii field isolates and subsequently heat-treated in a pilot-plant pasteurizer. Kinetic inactivation data in terms of D- and z-values were determined and used for the calculation of heat-dependent log reduction. With regard to the mandatory 5 log10-step reduction of the pathogen, the efficacy of the established heat treatment regime was confirmed, and, in addition, a reduction of the pasteurization temperature seems feasible.

Determination of Thermal Inactivation Kinetics of Microorganisms with a Continuous Microflow Apparatus

2004 ◽  
Vol 67 (11) ◽  
pp. 2560-2564 ◽  
Author(s):  
C. R. LOSS ◽  
J. H. HOTCHKISS
Keyword(s):  
Thermal Inactivation ◽  
Capillary Tube ◽  
Raw Milk ◽  
Heating Time ◽  
Inactivation Kinetics ◽  
Weibull Function ◽  
Stainless Steel Capillary ◽  
Heat Treated ◽  
Native Microflora ◽  
Kinetics Of

Use of a continuous microflow submerged microcoil (CSMC) apparatus was compared with the capillary tube (CT) method for measuring the thermal inactivation kinetics of Pseudomonas fluorescens at 61°C for 3 to 29 s. Inocula were continuously pumped through a microbore (≤0.0762 cm inside diameter) thin-walled stainless steel capillary tube submerged in a heated oil bath. The heating time was set by changing the flow rate, tube dimensions, or both. With the use of microthermo-couples, the time for the inocula to reach within 1°C of the set temperature was <3 s, and shorter than that with capillary tubes or vials. Inactivation curves (61°C) for P. fluorescens prepared by the CSMC method were not different from curves prepared by the CT method, as determined by analysis of variance (P > 0.05). Inactivation of Bacillus cereus spores (105°C) and native microflora found in raw milk (72°C) over heating times of 3 to 42 s were determined by CSMC. CSMC can measure thermal inactivation kinetics of microorganisms efficiently and simply at high temperatures and in short times. Survivors can be enumerated in 1-ml volumes of heat-treated samples, making it useful for determining inactivation kinetics of low numbers of microorganisms, such as those found in high-quality raw milk. Inactivation kinetics were generally more accurately described by the Weibull function (R2 ≥ 0.97) than the linear kinetic model.

scholarly journals Identification of Coxiella burnetii in Raw Milk of Livestock Animal in Iran

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Ashraf Mohabati Mobarez ◽  
Ehsan Mostafavi ◽  
Mohammad Khalili ◽  
Saber Esmaeili
Keyword(s):  
Real Time ◽  
Coxiella Burnetii ◽  
Real Time Pcr ◽  
Q Fever ◽  
Goat Milk ◽  
Raw Milk ◽  
Molecular Evidence ◽  
Milk Samples ◽  
Sheep Milk ◽  
Dairy Animals

Coxiella burnetii is the causative agent of Q fever in humans and animals. This study aimed to determine the frequency of C. burnetii in milk samples of dairy animals (goats, sheep, and cattle) in some selected regions in Iran, where there is no information about prevalence of C. burnetii. In this study, 162 individual milk samples were collected from 43 farms in three provinces (Tehran, Hamadan, and Mazandaran). Real-time PCR was used for the detection of IS1111a element of C. burnetii. In total, 23 of 162 samples (14.2%, 95% confidence interval (CI): 9.65–20.2%) were positive for C. burnetii by real-time PCR. C. burnetii was detected in 10.17% (95% CI: 4.74–20.46) of goat milk samples. In sheep milk samples, 18.6% (95% CI: 9.74–32.62) were positive, and C. burnetii was detected in 15% (95% CI: 8.1–26.11) of cattle milk samples. Molecular evidence of the presence of C. burnetii was seen in milk samples of dairy animals in all the studied regions. These findings demonstrated that C. burnetii infection, especially in raw milk samples, deserves more attention from the health care system and veterinary organization in Iran.

scholarly journals Prevalence of Coxiella Burnetii in Dairy Herds - Diagnostic Methods and Risk to Humans - A Review

2014 ◽  
Vol 58 (3) ◽  
pp. 337-340 ◽  
Author(s):  
Monika Szymańska-Czerwińska ◽  
Krzysztof Niemczuk ◽  
Agata Mitura
Keyword(s):  
Coxiella Burnetii ◽  
Disease Transmission ◽  
Q Fever ◽  
Raw Milk ◽  
Diagnostic Methods ◽  
Diagnostic Tools ◽  
Serological Tests ◽  
Prevalence Studies ◽  
Source Of Infection ◽  
Infection Dynamics

Abstract Q fever is a zoonotic disease caused by Coxiella burnetii. The main source of infection are ruminants (cattle, sheep, and goats). C. burnetii is excreted via birth products, vaginal mucus, milk, and faeces. Raw milk is considered useful for epidemiological examinations of animals and evaluation of infection dynamics at the herd level. This article summarises data on prevalence studies on C. burnetii in bulk-tank milk in different European countries with the means of serological tests and PCR. It also summarises the results of studies to evaluate the actual risk of disease transmission to humans through consumption of raw milk. Moreover, the available diagnostic tools for detection C. burnetii infection are presented.

Avoidance of the NLRP3 Inflammasome by the Stealth Pathogen, Coxiella burnetii

2020 ◽  
pp. 030098582098136
Author(s):  
Martha A. Delaney ◽  
Andreas den Hartigh ◽  
Samuel J. Carpentier ◽  
Timothy P. Birkland ◽  
Donald P. Knowles ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Q Fever ◽  
Bacterial Pathogen ◽  
In Vivo Model ◽  
Caspase 1 ◽  
Type Iv ◽  
Clinical Resistance ◽  
Nlrp3 Inflammasomes

Coxiella burnetii, a highly adapted obligate intracellular bacterial pathogen and the cause of the zoonosis Q fever, is a reemerging public health threat. C. burnetii employs a Type IV secretion system (T4SS) to establish and maintain its intracellular niche and modulate host immune responses including the inhibition of apoptosis. Interactions between C. burnetii and caspase-1-mediated inflammasomes are not fully elucidated. This study confirms that C. burnetii does not activate caspase-1 during infection of mouse macrophages in vitro. C. burnetii–infected cells did not develop NLRP3 and ASC foci indicating its ability to avoid cytosolic detection. C. burnetii is unable to inhibit the pyroptosis and IL-1β secretion that is induced by potent inflammasome stimuli but rather enhances these caspase-1-mediated effects. We found that C. burnetii upregulates pro-IL-1β and robustly primes NLRP3 inflammasomes via TLR2 and MyD88 signaling. As for wildtype C. burnetii, T4SS-deficient mutants primed and potentiated NLRP3 inflammasomes. An in vivo model of pulmonary infection in C57BL/6 mice was developed. Mice deficient in NLRP3 or caspase-1 were like wildtype mice in the development and resolution of splenomegaly due to red pulp hyperplasia, and histologic lesions and macrophage kinetics, but had slightly higher pulmonary bacterial burdens at the greatest measured time point. Together these findings indicate that C. burnetii primes but avoids cytosolic detection by NLRP3 inflammasomes, which are not required for the clinical resistance of C57BL/6 mice. Determining mechanisms employed by C. burnetii to avoid cytosolic detection via NLRP3 inflammasomes will be beneficial to the development of preventative and interventional therapies for Q fever.

Fluorometric Analysis of Alkaline Phosphatase Inactivation Correlated to Salmonella and Listeria Inactiviation

1992 ◽  
Vol 55 (12) ◽  
pp. 960-963 ◽  
Author(s):  
KARL F. ECKNER
Keyword(s):  
Alkaline Phosphatase ◽  
Bacterial Pathogen ◽  
Raw Milk ◽  
Fluorometric Assay ◽  
Pathogen Inactivation ◽  
Milk Samples ◽  
Test Conditions ◽  
Heat Treated ◽  
D Values ◽  
Salmonella Senftenberg

The correlation between alkaline phosphatase (ALP) inactivation and bacterial pathogen inactivation in raw milk was studied using a newly Association of Official Analytical Chemists-approved fluorometric assay (AOAC 991.24). Fresh, raw milk was inoculated with Listeria monocytogenes Scott A and Salmonella senftenberg 775W at levels of approximately 1 × 104 and 1 × 106 CFU/g milk, respectively. Milk was heat treated to target temperatures of 63 ± 0.5°C, 65 ± 0.5°C, 67 ± 0.5°C, 68 ± 0.5°C, or 71 ± 0.5°C in five trials. The D values calculated for S. senftenberg 775W ranged from 4.6 at 63°C to 0.17 at 71 °C with z values of 5.0 to 6.7. The D values calculated for L. monocytogenes Scott A ranged from 8.4 at 63°C to 0.19 at 71°C with z value of 4.8 to 6.1. Concomitantly, ALP concentration was monitored using a fluorometric assay. The inactivation rates of the test microbes were greater than or equal to that of alkaline phosphatase over the temperature range tested. The fluorometric assay exhibited excellent accuracy, precision, reproducibility, and repeatability under the test conditions. Viable test pathogens were isolated from milk samples with ALP levels corresponding to legal pasteurization requirements of < 500 milli-Units/L ALP activity assayed fluorometrically (=1.0μg phenol per mL/15 min) when inoculated with 1 × 106 CFU/g milk.

scholarly journals Seroprevalence and risk factors for Coxiella burnetii, the causative agent of Q fever in the dromedary camel (Camelus dromedarius) population in Algeria

2017 ◽  
Vol 84 (1) ◽  
Author(s):  
Mohammed H. Benaissa ◽  
Samir Ansel ◽  
Abdallah Mohamed-Cherif ◽  
Karima Benfodil ◽  
Djamel Khelef ◽  
...  
Keyword(s):  
Risk Factors ◽  
Logistic Regression ◽  
Coxiella Burnetii ◽  
Q Fever ◽  
Herd Size ◽  
Farm Animals ◽  
Enzyme Linked Immunosorbent Assay ◽  
Causative Organism ◽  
Dromedary Camel ◽  
Factors Associated

Query (Q) fever is a globally distributed zoonotic disease caused by Coxiella burnetii, a bacterial agent for which ruminants are the most prevalent natural reservoir. Data regarding Q fever infection in camels in Algeria are limited. Therefore, a survey to detect seroprevalence of C. burnetii antibodies was conducted among healthy camel populations in a vast area in southeastern Algeria to determine distribution of the Q fever causative organism and to identify risk factors associated with infection. Between January and March 2016, blood samples were collected from 184 camels and serum samples were subsequently analysed using a commercial Enzyme-Linked Immunosorbent Assay (ELISA) kit. At the time of blood collection, a questionnaire investigating 13 potential predisposing factors associated with C. burnetii seropositivity was completed for every dromedary camel and herd. Results were analysed by a chi-square (χ2) test and multivariate logistic regression. The seroprevalence of C. burnetii at the animal level was 71.2% (95% CI: 65.2–78.3) and 85.3% (95% CI: 72.8–97.8) at the herd level. At the animal level, differences in seroprevalence were observed because of herd size, animal age, animal sex, presence of ticks and contact with other herds. A multivariable logistic regression model identified three main risk factors associated with individual seropositivity: (1) age class > 11 years (OR = 8.81, 95% CI: 2.55–30.41), (2) herd size > 50 head (OR = 4.46, 95% CI: 1.01–19.59) and (3) infestation with ticks (OR 2.2; 95% CI: 1.1–4.5). This study of seroprevalence of C. burnetii infection in camels in Algeria revealed a high seroprevalence of Q fever in camel populations in southeastern Algeria and provided strong evidence that Q fever represents an economic, public health and veterinary concern. Appropriate measures should be taken to prevent the spread of C. burnetii and to reduce the risk of Q fever in farm animals and humans in this agro-ecologically and strategically important region of North Africa.

scholarly journals Tick-Borne Encephalitis Virus, Coxiella burnetii & Brucella spp. in Milk, Kazakhstan

2016 ◽  
Vol 8 (1) ◽  
Author(s):  
John Hay ◽  
Christina Farris ◽  
Phil Elzer ◽  
Alexei Andrushchenko ◽  
Sue Hagius ◽  
...  
Keyword(s):  
Coxiella Burnetii ◽  
Q Fever ◽  
Raw Milk ◽  
Encephalitis Virus ◽  
Western Kazakhstan ◽  
Tick Borne Encephalitis ◽  
Tick Borne Encephalitis Virus ◽  
Species Specific ◽  
Positive Results ◽  
Positive Controls

Raw milk was collected from cows in western Kazakhstan in winter 2014-2015. Samples were defatted and frozen at -20C, then tested as follows. For tick-borne encephalitis virus, 65 samples were tested using the VectorBest TBEV antigen capture kit, with 9% positive. For Coxiella burnetii, 50 samples were assayed using a species-specific qPCR assay and all were negative, though positive controls were consistently positive. For Brucella spp., PCR, ELISA and FPA testing is ongoing, with some positive results. These data suggest that consumption of raw cow's milk in western Kazakhstan is a risk factor for tick-borne encephalitis and brucellosis. The risk for Q fever appears to be small during winter, but may be present at other times of the year.

Coxiella burnetii infection in a patient did not involve tick bite

2020 ◽  
Author(s):  
changwoo kim ◽  
Choon Mee Kim ◽  
Na Ra Yun ◽  
Dong-Min Kim
Keyword(s):  
16S Rrna ◽  
Serum Sample ◽  
Coxiella Burnetii ◽  
Q Fever ◽  
Spotted Fever ◽  
Bacterial Species ◽  
Raw Milk ◽  
Human Infection ◽  
Haemaphysalis Longicornis ◽  
Igg Antibody

Abstract Background: Coxiella burnetii that causes Q fever in humans is transmitted through contaminated aerosols or consumption of raw milk from infected animals. Ticks are known to be vectors of C. burnetii, but their role in human infection is still controversial. Method: In this study, an epidemiological investigation was conducted on a 60-year-old man hospitalized with fever. Polymerase chain reactions (PCRs) were performed on the blood sample of the patient and the four ticks collected from the patient to diagnose vector-borne infectious diseases. Indirect immunofluorescence assays (IFAs) were performed on the serum sample to detect IgG and IgM antibodies specific to Q fever, spotted fever, Lyme disease, and anaplasmosis. Results: The ticks collected were identified as adult female Haemaphysalis longicornis. All PCRs performed on blood specimens yielded negative results, except for the Coxiella sp.-specific 16S rRNA nested PCR (N-PCR). Coxiella 16S rRNA N-PCR and sequencing results confirmed the presence of C. burnetii. IFA results indicated that the serum sample showed ≥ 4-fold increase in both IgM and IgG antibody titers against Q fever. PCR results were positive only for three ticks and showed the presence of C. endosymbiont. The phylogenetic tree showed that ticks had Coxiella-like bacteria and the patient had C. burnetii. The ticks carrying Coxiella-like bacteria were Haemaphysalis symbionts. Conclusions: Even though the patient and ticks were all positive to Coxiella sp.-specific 16S rRNA N-PCR, since different bacterial species were isolated from the patient and the ticks, we concluded that he was not infected with C. burnetii through tick bites.

scholarly journals Two Systems for Targeted Gene Deletion in Coxiella burnetii

2012 ◽  
Vol 78 (13) ◽  
pp. 4580-4589 ◽  
Author(s):  
Paul A. Beare ◽  
Charles L. Larson ◽  
Stacey D. Gilk ◽  
Robert A. Heinzen
Keyword(s):  
Coxiella Burnetii ◽  
Gene Deletion ◽  
Q Fever ◽  
Shuttle Vector ◽  
Bacterial Pathogen ◽  
Host Cells ◽  
Suicide Plasmid ◽  
Content Type ◽  
Targeted Gene Deletion ◽  
Flanking Regions

ABSTRACTCoxiella burnetiiis a ubiquitous zoonotic bacterial pathogen and the cause of human acute Q fever, a disabling influenza-like illness.C. burnetii's former obligate intracellular nature significantly impeded the genetic characterization of putative virulence factors. However, recent host cell-free (axenic) growth of the organism has enabled development of shuttle vector, transposon, and inducible gene expression technologies, with targeted gene inactivation remaining an important challenge. In the present study, we describe two methods for generating targeted gene deletions inC. burnetiithat exploit pUC/ColE1ori-based suicide plasmids encodingsacBfor positive selection of mutants. As proof of concept,C. burnetiidotA anddotB, encoding structural components of the type IVB secretion system (T4BSS), were selected for deletion. The first method exploited Cre-lox-mediated recombination. Two suicide plasmids carrying different antibiotic resistance markers and aloxPsite were integrated into 5′ and 3′ flanking regions ofdotA. Transformation of this strain with a third suicide plasmid encoding Cre recombinase resulted in the deletion ofdotAunder sucrose counterselection. The second method utilized a loop-in/loop-out strategy to deletedotAanddotB.A single suicide plasmid was first integrated into 5′ or 3′ target gene flanking regions. Resolution of the plasmid cointegrant by a second crossover event under sucrose counterselection resulted in gene deletion that was confirmed by PCR and Southern blot. ΔdotAand ΔdotBmutants failed to secrete T4BSS substrates and to productively infect host cells. The repertoire ofC. burnetiigenetic tools now allows ready fulfillment of molecular Koch's postulates for suspected virulence genes.

scholarly journals Validation of a Novel Commercial ELISA Test for the Detection of Antibodies against Coxiella burnetii

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1075
Author(s):  
Salvatore Ledda ◽  
Cinzia Santucciu ◽  
Valentina Chisu ◽  
Giovanna Masala
Keyword(s):  
Diagnostic Accuracy ◽  
Phase Ii ◽  
Coxiella Burnetii ◽  
Q Fever ◽  
Animal Health ◽  
Elisa Test ◽  
Clinical Diagnostics ◽  
Complex Life Cycle ◽  
Enzyme Linked Immunosorbent Assay ◽  
Specificity And Sensitivity

Q fever is a zoonosis caused by Coxiella burnetii, a Gram-negative pathogen with a complex life cycle and a high impact on public and animal health all over the world. The symptoms are indistinguishable from those belonging to other diseases, and the disease could be symptomless. For these reasons, reliable laboratory tests are essential for an accurate diagnosis. The aim of this study was to validate a novel enzyme-linked immunosorbent assay (ELISA) test, named the Chorus Q Fever Phase II IgG and IgM Kit (DIESSE, Diagnostica Senese S.p.A), which is performed by an instrument named Chorus, a new device in medical diagnostics. This diagnostic test is employed for the detection of antibodies against C. burnetii Phase II antigens in acute disease. Our validation protocol was performed according to the Italian Accreditation Body (ACCREDIA) (Regulation UNI CEI EN ISO/IEC 17025:2018 and 17043:2010), OIE (World Organization for Animal Health), and Statement for Reporting Studies of Diagnostic Accuracy (STARD). Operator performance was evaluated along with the analytical specificity and sensitivity (ASp and ASe) and diagnostic accuracy of the kit, with parameters such as diagnostic specificity and sensitivity (DSp and DSe) and positive and negative predictive values (PPV and NPV), in addition to the repeatability. According to the evaluated parameters, the diagnostic ELISA test was shown to be suitable for validation and commercialization as a screening method in human sera and a valid support for clinical diagnostics.

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