American journal of reproductive immunology and microbiology : AJRIM, Sep 1, 2002
ABSTRACT Pregnancy has an important impact on the maternal immune system, associated with a shift... more ABSTRACT Pregnancy has an important impact on the maternal immune system, associated with a shift in the Th1/Th2 cytokine balance towards a type-2 response. However, listeria induced Th1 type cytokines are essential in host protection against this facultative intracellular bacterium. We have analyzed and compared the kinetics of maternal serum concentrations of IFN-γ, IL-10, TNF-α, IL-6 and KC by ELISA. Serum IFN-γ levels in infected pregnant mice were significantly reduced in comparison to infected virgin animals, while IL-10 levels were increased, being significantly higher on days 3 and 6 p.i. as compared to infected virgin mice. Upon L. monocytogenes infection, circulating TNF-α concentrations were below the detection limit. However, on day 6 p.i., in pregnant mice elevated levels of TNF-α were noticed, correlating to the severity of disease. Increased concentrations of IL-6 have been shown to follow the kinetics of bacterial numbers in the liver of infected animals. Murine chemokine KC production in maternal circulation followed a similar pattern as IL-6. In comparison to virgin animals, pregnant mice mount lower levels of protective Th1 cytokines and are unable to eliminate the pathogen. Increased serum concentrations of IL-10, along with proinflammatory cytokines, may well contribute to the severity of pregnancy-associated listeriosis. Maternal serum IL-6 level showed the highest correlation with the course of infection and pregnancy outcome.
Abstract: Autoagregacija i koagregacija vane su karakteristike potencijalnih probiotičkih bakter... more Abstract: Autoagregacija i koagregacija vane su karakteristike potencijalnih probiotičkih bakterija. Autoagregacija je neophodna za adheziju na epitelne stanice crijeva. Koagregacija omogućava probiotičkim sojevima da inhibiraju potencijalno patogene ...
Journal of Maternal-fetal & Neonatal Medicine, Oct 29, 2012
Listeria monocytogenes usually causes mild maternal illness, but can be devastating to the fetus.... more Listeria monocytogenes usually causes mild maternal illness, but can be devastating to the fetus. Listeriosis in a pregnant patient successfully treated with empiric antibiotic therapy is described. After induced delivery, despite severe placental infection, a healthy infant was born. Additionally, archived placental specimens with similar pathological manifestation were evaluated for evidence of L. monocytogenes. It is important to emphasize the value of associating maternal data and clinical and laboratory findings of the newborn with the pathologic placental findings to get better results in the etiologic diagnosis of the listeriosis.
Fems Immunology and Medical Microbiology, Apr 1, 2003
Listeria monocytogenes has been recognized as a significant pathogen, occurring worldwide, capabl... more Listeria monocytogenes has been recognized as a significant pathogen, occurring worldwide, capable of causing animal and human infections. In its most severe form, listeriosis is an invasive disease that affects immunocompromised patients. Additionally, pregnant women represent a high-risk group for L. monocytogenes infection. Abortion, stillbirth or severe neonatal infection can be the serious outcome of such an infection. In an
Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Ob... more Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Obstetrics & Gynecology. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but ...
American Journal of Reproductive Immunology, Sep 2, 2007
Listeria monocytogenes infection causes serious morbidity during the fetal and neonatal period. I... more Listeria monocytogenes infection causes serious morbidity during the fetal and neonatal period. In order to determine the importance of TNF-α and TNFR1 signalling in antilisterial immunity, neonatal TNFR1 KO mice were infected with L. monocytogenes. The course of infection, pathological changes, cellular response and expression of different mediators in neonatal liver and brain were studied. Two days old TNFR1 KO mice and age-matched C57BL/6 controls were i.p. infected with actA deficient L. monocytogenes. Tissue sections were analysed using immunohistochemistry. RT-PCR was used to delineate the time course of the local, liver and brain, expression of mRNA encoding IFN-γ , TNF- , iNOS and IDO. 100% of the TNR1 KO mice succumbed while all C57BL/6 survived the infection. The impaired clearance of bacteria from the organs of TNFR1 KO mice resulted in development of necrotic hepatitis, meningoencephalitis and brain abscesses. In neonatal control mice the infection resulted in weak induction of hepatic and brain mRNA for TNF-α and IFN-γ . On contrary, in the liver of TNR1 KO mice these cytokines were not up-regulated, but IFN- γ was strongly enhanced in the brain tissue. De novo synthesis of iNOS and increased expression of mRNA for IDO were detected in the liver and brain of KO mice. C57BL/6 neonatal mice successfully face the L. monocytogenes infection. The course of listeriosis and mortality rate of TNFR1 KO mice shows the critical importance of TNFR1 in antilisterial immunity. Disturbance of the inflammatory mediators’ production implies the complex role of TNF-α in neonatal immune response against L. monocytogenes.
We studied the course of Listeria monocytogenes infection in BALB/c mice challanged intragastrica... more We studied the course of Listeria monocytogenes infection in BALB/c mice challanged intragastrically (i.g.), in an attempt to mimic natural listeriosis. The systemic infection was confirmed by positive blood cultures and a high titer of bacteria in the livers of all infected mice. However, repeated lower doses increased the severity of liver infection, resulting in a pronounced necrotizing hepatitis and extreme metabolic liver disfunction according to high levels of serum aminotransferases. During the inflammatory event, chemokine concentrations typically increased more at the local site compared to systemic level. The liver to serum ratio was most pronounced in the case of MIP-1alpha, suggesting its role in the necroinflammatory response in the liver.
The impact of L. monocytogenes infection on the maternal immune response as well as on the outcom... more The impact of L. monocytogenes infection on the maternal immune response as well as on the outcome of pregnancy was studied in a murine model of pregnancy-associated listeriosis. BALB/c mice infected intravenously with L.monocytogenes on day 15 of pregnancy showed impaired bacterial elimination from the liver. The impaired maternal immune response faciliated bacterial multiplication in the placenta and, ultimately, in the fetus. Placental colonization involved all or only some of the placentas in the same uterus. Despite marked pathohistological changes and numerous bacteria, the imflammatory reaction was confined to single granulocytes, but T cells and other cellular elements necessary for effective antilisterial defence were absent. The severity of placental infection predicted whether the fetus was aborted or resorbed. Listeriae were frequently detected in the tissues of the resorbing fetuses while only occasionally from the tissues of the aborted fetuses. In conclusion, our experimental model proved insufficient maternal immune response to L. monocytogenes during pregnancy. This stresses the necessity of a rapid therapeutic intervention to prevent bacterial multiplication in the placenta.
Listeria monocytogenes is gram - positive bacterium associated with potentially serious invasive ... more Listeria monocytogenes is gram - positive bacterium associated with potentially serious invasive diseases in humans and in a variety of animal species. Because of ubiquitous distribution in the environment, L. monocytogenes may be involved in the interactions with free-living protozoa, a common representative of natural ecosystems. We investigated the interactions of haemolytic L. monocytogenes (EGD strain) with the free-living amoeba, Acanthamoeba castellanii (ATCC 30234). Survival of bacteria and amoeba was checked at regular intervals, coupled with microscopy. At 22oC, as well as at 35oC, listeria was internalized into A. castellanii but was not able to establish an intracellular lifestyle within the eucaryotic host. It was shown, by gentamicin protection assays, that L. monocytogenes could be recovered by culture only four hours after coculture establishment. L. monocytogenes had no killing effect on the amoebae but did cause rapid protozoan encysment, probably thanks to LLO production. However, the presence of amoeba enhanced the growth of listeria according to higher numbers of extra cellular bacteria when cultured with amoebae compared with growth in their absence. Higher numbers were likely sustained on metabolic waste products released during coculture. Although free-living amoeba and listeria may be found in the same environment it seems that L. monocytogenes is not maintained nor transferred in the environment by association with Acanthamoeba castellanii. However, presence of acanthamoeba seems to be beneficial for microorganism and it could thus be speculated that such cointeraction is also important for L. monocytogenes survival in its natural environment.
To explore the interaction effects of ciprofloxacin and ampicillin with nickel on the growth of b... more To explore the interaction effects of ciprofloxacin and ampicillin with nickel on the growth of bacteria, Staphylococcus aureus strain ATCC 29213, Enterococcus faecalis ATCC 29212 and Escherichia coli ATCC 25922 were used. Minimum inhibitory concentrations (MICs) were determined for nickel, ciprofloxacin and ampicillin, and the checkerboard method was used to assess their cumulative effects on bacterial growth. The interactions between the metal and antibiotics were assessed by the fractional inhibitory concentration (FIC). The MICs for ciprofloxacin and ampicillin were 0.31 and 1 mg/L for E. faecalis, 0.62 and 1 mg/L for S. aureus and 0.005 and 2.5 for E. coli, respectively. The MIC for nickel was 1000 mg/L for all bacteria. The FIC results for ciprofloxacin and nickel demonstrated an antagonistic effect of the two agents on the growth of E. coli and E. faecalis and an additive effect on S. aureus. The FICs for ampicillin and nickel demonstrated a synergistic effect on the growth of E. faecalis and E. coli. Different interactions of metals and antibiotics were observed depending on the bacteria and the type of antibiotic.
American journal of reproductive immunology and microbiology : AJRIM, Sep 1, 2002
ABSTRACT Pregnancy has an important impact on the maternal immune system, associated with a shift... more ABSTRACT Pregnancy has an important impact on the maternal immune system, associated with a shift in the Th1/Th2 cytokine balance towards a type-2 response. However, listeria induced Th1 type cytokines are essential in host protection against this facultative intracellular bacterium. We have analyzed and compared the kinetics of maternal serum concentrations of IFN-γ, IL-10, TNF-α, IL-6 and KC by ELISA. Serum IFN-γ levels in infected pregnant mice were significantly reduced in comparison to infected virgin animals, while IL-10 levels were increased, being significantly higher on days 3 and 6 p.i. as compared to infected virgin mice. Upon L. monocytogenes infection, circulating TNF-α concentrations were below the detection limit. However, on day 6 p.i., in pregnant mice elevated levels of TNF-α were noticed, correlating to the severity of disease. Increased concentrations of IL-6 have been shown to follow the kinetics of bacterial numbers in the liver of infected animals. Murine chemokine KC production in maternal circulation followed a similar pattern as IL-6. In comparison to virgin animals, pregnant mice mount lower levels of protective Th1 cytokines and are unable to eliminate the pathogen. Increased serum concentrations of IL-10, along with proinflammatory cytokines, may well contribute to the severity of pregnancy-associated listeriosis. Maternal serum IL-6 level showed the highest correlation with the course of infection and pregnancy outcome.
Abstract: Autoagregacija i koagregacija vane su karakteristike potencijalnih probiotičkih bakter... more Abstract: Autoagregacija i koagregacija vane su karakteristike potencijalnih probiotičkih bakterija. Autoagregacija je neophodna za adheziju na epitelne stanice crijeva. Koagregacija omogućava probiotičkim sojevima da inhibiraju potencijalno patogene ...
Journal of Maternal-fetal & Neonatal Medicine, Oct 29, 2012
Listeria monocytogenes usually causes mild maternal illness, but can be devastating to the fetus.... more Listeria monocytogenes usually causes mild maternal illness, but can be devastating to the fetus. Listeriosis in a pregnant patient successfully treated with empiric antibiotic therapy is described. After induced delivery, despite severe placental infection, a healthy infant was born. Additionally, archived placental specimens with similar pathological manifestation were evaluated for evidence of L. monocytogenes. It is important to emphasize the value of associating maternal data and clinical and laboratory findings of the newborn with the pathologic placental findings to get better results in the etiologic diagnosis of the listeriosis.
Fems Immunology and Medical Microbiology, Apr 1, 2003
Listeria monocytogenes has been recognized as a significant pathogen, occurring worldwide, capabl... more Listeria monocytogenes has been recognized as a significant pathogen, occurring worldwide, capable of causing animal and human infections. In its most severe form, listeriosis is an invasive disease that affects immunocompromised patients. Additionally, pregnant women represent a high-risk group for L. monocytogenes infection. Abortion, stillbirth or severe neonatal infection can be the serious outcome of such an infection. In an
Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Ob... more Advertisement. Close Window. Close Window. Thank you for choosing to subscribe to the eTOC for Obstetrics & Gynecology. Enter your Email address: Wolters Kluwer Health may email you for journal alerts and information, but ...
American Journal of Reproductive Immunology, Sep 2, 2007
Listeria monocytogenes infection causes serious morbidity during the fetal and neonatal period. I... more Listeria monocytogenes infection causes serious morbidity during the fetal and neonatal period. In order to determine the importance of TNF-α and TNFR1 signalling in antilisterial immunity, neonatal TNFR1 KO mice were infected with L. monocytogenes. The course of infection, pathological changes, cellular response and expression of different mediators in neonatal liver and brain were studied. Two days old TNFR1 KO mice and age-matched C57BL/6 controls were i.p. infected with actA deficient L. monocytogenes. Tissue sections were analysed using immunohistochemistry. RT-PCR was used to delineate the time course of the local, liver and brain, expression of mRNA encoding IFN-γ , TNF- , iNOS and IDO. 100% of the TNR1 KO mice succumbed while all C57BL/6 survived the infection. The impaired clearance of bacteria from the organs of TNFR1 KO mice resulted in development of necrotic hepatitis, meningoencephalitis and brain abscesses. In neonatal control mice the infection resulted in weak induction of hepatic and brain mRNA for TNF-α and IFN-γ . On contrary, in the liver of TNR1 KO mice these cytokines were not up-regulated, but IFN- γ was strongly enhanced in the brain tissue. De novo synthesis of iNOS and increased expression of mRNA for IDO were detected in the liver and brain of KO mice. C57BL/6 neonatal mice successfully face the L. monocytogenes infection. The course of listeriosis and mortality rate of TNFR1 KO mice shows the critical importance of TNFR1 in antilisterial immunity. Disturbance of the inflammatory mediators’ production implies the complex role of TNF-α in neonatal immune response against L. monocytogenes.
We studied the course of Listeria monocytogenes infection in BALB/c mice challanged intragastrica... more We studied the course of Listeria monocytogenes infection in BALB/c mice challanged intragastrically (i.g.), in an attempt to mimic natural listeriosis. The systemic infection was confirmed by positive blood cultures and a high titer of bacteria in the livers of all infected mice. However, repeated lower doses increased the severity of liver infection, resulting in a pronounced necrotizing hepatitis and extreme metabolic liver disfunction according to high levels of serum aminotransferases. During the inflammatory event, chemokine concentrations typically increased more at the local site compared to systemic level. The liver to serum ratio was most pronounced in the case of MIP-1alpha, suggesting its role in the necroinflammatory response in the liver.
The impact of L. monocytogenes infection on the maternal immune response as well as on the outcom... more The impact of L. monocytogenes infection on the maternal immune response as well as on the outcome of pregnancy was studied in a murine model of pregnancy-associated listeriosis. BALB/c mice infected intravenously with L.monocytogenes on day 15 of pregnancy showed impaired bacterial elimination from the liver. The impaired maternal immune response faciliated bacterial multiplication in the placenta and, ultimately, in the fetus. Placental colonization involved all or only some of the placentas in the same uterus. Despite marked pathohistological changes and numerous bacteria, the imflammatory reaction was confined to single granulocytes, but T cells and other cellular elements necessary for effective antilisterial defence were absent. The severity of placental infection predicted whether the fetus was aborted or resorbed. Listeriae were frequently detected in the tissues of the resorbing fetuses while only occasionally from the tissues of the aborted fetuses. In conclusion, our experimental model proved insufficient maternal immune response to L. monocytogenes during pregnancy. This stresses the necessity of a rapid therapeutic intervention to prevent bacterial multiplication in the placenta.
Listeria monocytogenes is gram - positive bacterium associated with potentially serious invasive ... more Listeria monocytogenes is gram - positive bacterium associated with potentially serious invasive diseases in humans and in a variety of animal species. Because of ubiquitous distribution in the environment, L. monocytogenes may be involved in the interactions with free-living protozoa, a common representative of natural ecosystems. We investigated the interactions of haemolytic L. monocytogenes (EGD strain) with the free-living amoeba, Acanthamoeba castellanii (ATCC 30234). Survival of bacteria and amoeba was checked at regular intervals, coupled with microscopy. At 22oC, as well as at 35oC, listeria was internalized into A. castellanii but was not able to establish an intracellular lifestyle within the eucaryotic host. It was shown, by gentamicin protection assays, that L. monocytogenes could be recovered by culture only four hours after coculture establishment. L. monocytogenes had no killing effect on the amoebae but did cause rapid protozoan encysment, probably thanks to LLO production. However, the presence of amoeba enhanced the growth of listeria according to higher numbers of extra cellular bacteria when cultured with amoebae compared with growth in their absence. Higher numbers were likely sustained on metabolic waste products released during coculture. Although free-living amoeba and listeria may be found in the same environment it seems that L. monocytogenes is not maintained nor transferred in the environment by association with Acanthamoeba castellanii. However, presence of acanthamoeba seems to be beneficial for microorganism and it could thus be speculated that such cointeraction is also important for L. monocytogenes survival in its natural environment.
To explore the interaction effects of ciprofloxacin and ampicillin with nickel on the growth of b... more To explore the interaction effects of ciprofloxacin and ampicillin with nickel on the growth of bacteria, Staphylococcus aureus strain ATCC 29213, Enterococcus faecalis ATCC 29212 and Escherichia coli ATCC 25922 were used. Minimum inhibitory concentrations (MICs) were determined for nickel, ciprofloxacin and ampicillin, and the checkerboard method was used to assess their cumulative effects on bacterial growth. The interactions between the metal and antibiotics were assessed by the fractional inhibitory concentration (FIC). The MICs for ciprofloxacin and ampicillin were 0.31 and 1 mg/L for E. faecalis, 0.62 and 1 mg/L for S. aureus and 0.005 and 2.5 for E. coli, respectively. The MIC for nickel was 1000 mg/L for all bacteria. The FIC results for ciprofloxacin and nickel demonstrated an antagonistic effect of the two agents on the growth of E. coli and E. faecalis and an additive effect on S. aureus. The FICs for ampicillin and nickel demonstrated a synergistic effect on the growth of E. faecalis and E. coli. Different interactions of metals and antibiotics were observed depending on the bacteria and the type of antibiotic.
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