muramidase and Pneumococcal-Infections

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Anti-Inflammatory Agents; Bacteria; Drug Synergism; Female; Fever; Genital Diseases, Female; Guinea Pigs; Haplorhini; Humans; Infections; Inflammation; Mice; Muramidase; Penicillins; Peritoneal Diseases; Phagocytosis; Pneumococcal Infections; Rabbits; Rats; Staphylococcal Infections; Urologic Diseases; Virus Diseases; Viruses

To test the synergistic effect of Cpl-711 endolysin and antibiotics for antipneumococcal activity.. A combination of Cpl-711 and different antibiotics (amoxicillin, cefotaxime, levofloxacin and vancomycin) was tested in a checkerboard assay against several multidrug-resistant Streptococcus pneumoniae strains. Mouse and zebrafish models of pneumococcal sepsis were used to confirm the in vitro data.. The activity of Cpl-711 combined with amoxicillin or cefotaxime was synergistic in the bactericidal effect against a serotype 23F multiresistant clinical isolate of S. pneumoniae. Synergy between Cpl-711 and cefotaxime was validated using both mouse and zebrafish models.. Combination of Cpl-711 and cefotaxime may help in the treatment of diseases caused by multiresistant pneumococcal strains.

Topics: Animals; Anti-Bacterial Agents; Cefotaxime; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Drug Synergism; Female; Mice; Mice, Inbred BALB C; Muramidase; Pneumococcal Infections; Recombinant Fusion Proteins; Sepsis; Streptococcus Phages; Streptococcus pneumoniae; Zebrafish

To study the biological character and pathogenic effect of a lysozyme-like protein in Streptococcus pneumoniae.. The gene knockout mutant was constructed by the long flanking homology polymerase chain reaction. The mutant containing rescue plasmid to complement the lysozyme-like gene was also constructed. The differences in biology and pathogenicity in D39 wild strain, gene knockout mutant and gene knockout mutant containing rescue plasmid were observed to identify the functions of the lysozyme-like gene.. Compared with the wild strain, the gene knockout mutant had the characteristics of slower growth, declining virulence, and obviously reduced capsule polysaccharide synthesis. Complement experiment showed when the rescue plasmid was transformed into the mutant strain, the mRNA level of hypothetical lysozyme-like gene in the gene knockout mutant containing rescue plasmid was higher than that of the wild strain. Although the levels of virulence and capsule polysaccharide synthesis could be partly complemented compared with those of the gene knockout mutant, but not reached the levels in the wild strain.. The lysozyme-like protein, a new Streptococcus pneumoniae virulence factor, may regulate the proliferation and the capsular polysaccharides synthesis of Streptococcus pneumoniae to affect expression of virulence.

Topics: Animals; Bacterial Capsules; Bacterial Proteins; Humans; Mice; Mice, Inbred BALB C; Muramidase; Pneumococcal Infections; Streptococcus pneumoniae; Virulence

Streptococcus pneumoniae colonizes the mucosal surface of the human upper respiratory tract. A colonization event is gradually cleared through phagocytosis by monocytes/macrophages that are recruited to the airway lumen. Here, we sought to define the bacterial and host factors that promote monocyte/macrophage influx and S. pneumoniae clearance using intranasal bacterial challenge in mice. We found that the recruitment of monocytes/macrophages required their expression of the chemokine receptor CCR2 and correlated with expression of the CCR2 ligand CCL2. Production of CCL2 and monocyte/macrophage recruitment were deficient in mice lacking digestion of peptidoglycan by lysozyme (LysM) and cytosolic sensing of the products of digestion by Nod2. Ex vivo macrophages produced CCL2 following bacterial uptake, digestion by LysM, and sensing of peptidoglycan by Nod2. Sensing of digested peptidoglycan by Nod2 also required the pore-forming toxin pneumolysin. The generation of an adaptive immune response, as measured by anti-pneumococcal antibody titers, was also LysM- and Nod2-dependent. Together, our data suggest that bacterial uptake by professional phagocytes is followed by LysM-mediated digestion of S. pneumoniae-derived peptidoglycan, sensing of the resulting products by Nod2, release of the chemokine CCL2, and CCR2-dependent recruitment of the additional monocytes/macrophages required for the clearance of an S. pneumoniae colonization event.

Topics: Adaptive Immunity; Animals; Chemokine CCL2; Humans; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Muramidase; Nod2 Signaling Adaptor Protein; Peptidoglycan; Phagocytes; Pneumococcal Infections; Receptors, CCR2; Streptococcus pneumoniae; Toll-Like Receptor 2

Lysozyme is an antimicrobial innate immune molecule degrading peptidoglycan of the bacterial cell wall. Lysozyme shows the ubiquitous expression in wide varieties of species and tissues including the tubotympanum of mammals. We aim to investigate the effects of lysozyme depletion on pneumococcal clearance from the middle ear cavity.. Immunohistochemistry was performed to localize lysozyme in the Eustachian tube. Lysozyme expression was compared between the wild type and the lysozyme M-/- mice using real time quantitative RT-PCR and western blotting. Muramidase activity and bactericidal activity of lysozyme was measured using a lysoplate radial diffusion assay and a liquid broth assay, respectively. To determine if depletion of lysozyme M increases a susceptibility to pneumococal otitis media, 50 CFU of S. pneumoniae 6B were transtympanically inoculated to the middle ear and viable bacteria were counted at day 3 and 7 with clinical grading of middle ear inflammation.. Immunolabeling revealed that localization of lysozyme M and lysozyme P is specific to some/particular cell types of the Eustachian tube. Lysozyme P of lysozyme M-/- mice was mainly expressed in the submucosal gland but not in the tubal epithelium. Although lysozyme M-/- mice showed compensatory up-regulation of lysozyme P, lysozyme M depletion resulted in a decrease in both muramidase and antimicrobial activities. Deficiency in lysozyme M led to an increased susceptibility to middle ear infection with S. pneumoniae 6B and resulted in severe middle ear inflammation, compared to wild type mice.. The results suggest that lysozyme M plays an important role in protecting the middle ear from invading pathogens, particularly in the early phase. We suggest a possibility of the exogenous lysozyme as an adjuvant therapeutic agent for otitis media, but further studies are necessary.

Topics: Animals; Disease Susceptibility; Eustachian Tube; Gene Expression Profiling; Gene Expression Regulation; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Muramidase; Otitis Media; Pneumococcal Infections; Reverse Transcriptase Polymerase Chain Reaction; RNA; Streptococcus pneumoniae

The abundance of lysozyme on mucosal surfaces suggests that successful colonizers must be able to evade its antimicrobial effects. Lysozyme has a muramidase activity that hydrolyzes bacterial peptidoglycan and a non-muramidase activity attributable to its function as a cationic antimicrobial peptide. Two enzymes (PgdA, a N-acetylglucosamine deacetylase, and Adr, an O-acetyl transferase) that modify different sites on the peptidoglycan of Streptococcus pneumoniae have been implicated in its resistance to lysozyme in vitro. Here we show that the antimicrobial effect of human lysozyme is due to its muramidase activity and that both peptidoglycan modifications are required for full resistance by pneumococci. To examine the contribution of lysozyme and peptidoglycan modifications during colonization of the upper respiratory tract, competition experiments were performed with wild-type and pgdAadr mutant pneumococci in lysozyme M-sufficient (LysM(+/+)) and -deficient (LysM(-/-)) mice. The wild-type strain out-competed the double mutant in LysM(+/+), but not LysM(-/-) mice, indicating the importance of resistance to the muramidase activity of lysozyme during mucosal colonization. In contrast, strains containing single mutations in either pgdA or adr prevailed over the wild-type strain in both LysM(+/+) and LysM(-/-) mice. Our findings demonstrate that individual peptidoglycan modifications diminish fitness during colonization. The competitive advantage of wild-type pneumococci in LysM(+/+) but not LysM(-/-) mice suggests that the combination of peptidoglycan modifications reduces overall fitness, but that this is outweighed by the benefits of resistance to the peptidoglycan degrading activity of lysozyme.

Topics: Acetyltransferases; Amidohydrolases; Animals; Bacterial Capsules; Bacterial Proteins; Cell Wall; Female; Humans; Mice; Muramidase; Mutation; Nasopharynx; Neutrophils; Peptidoglycan; Pneumococcal Infections; Respiratory Mucosa; Respiratory Tract Infections; Streptococcus pneumoniae

Topics: Acute Disease; Administration, Intranasal; Animals; Disease Models, Animal; Female; Humans; Influenza, Human; Mice; Mice, Inbred BALB C; Muramidase; Orthomyxoviridae; Otitis Media; Pneumococcal Infections; Streptococcus pneumoniae

The in vitro and in vivo antipneumococcal activities of the main pneumococcal autolysin (LytA) and Cpl-1, a lysozyme encoded by phage Cp-1, were studied. Intraperitoneal therapy with LytA or high-dose Cpl-1 remarkably reduced peritoneal bacterial counts (>5 log(10) CFU/ml) compared with those for the controls. After intravenous injection, LytA was the most effective treatment.

Topics: Animals; Anti-Bacterial Agents; Ascitic Fluid; Bacteriophages; beta-Lactams; Colony Count, Microbial; Drug Resistance, Bacterial; Injections, Intraperitoneal; Injections, Intravenous; Mice; Microbial Sensitivity Tests; Muramidase; N-Acetylmuramoyl-L-alanine Amidase; Peritonitis; Pneumococcal Infections; Streptococcus pneumoniae

Streptococcus pneumoniae colonizes the human upper respiratory tract, and this asymptomatic colonization is known to precede pneumococcal disease. In this report, chemically defined and semisynthetic media were used to identify the initial steps of biofilm formation by pneumococcus during growth on abiotic surfaces such as polystyrene or glass. Unencapsulated pneumococci adhered to abiotic surfaces and formed a three-dimensional structure about 25 microm deep, as observed by confocal laser scanning microscopy and low-temperature scanning electron microscopy. Choline residues of cell wall teichoic acids were found to play a fundamental role in pneumococcal biofilm development. The role in biofilm formation of choline-binding proteins, which anchor to the teichoic acids of the cell envelope, was determined using unambiguously characterized mutants. The results showed that LytA amidase, LytC lysozyme, LytB glucosaminidase, CbpA adhesin, PcpA putative adhesin, and PspA (pneumococcal surface protein A) mutants had a decreased capacity to form biofilms, whereas no such reduction was observed in Pce phosphocholinesterase or CbpD putative amidase mutants. Moreover, encapsulated, clinical pneumococcal isolates were impaired in their capacity to form biofilms. In addition, a role for extracellular DNA and proteins in the establishment of S. pneumoniae biofilms was demonstrated. Taken together, these observations provide information on conditions that favor the sessile mode of growth by S. pneumoniae. The experimental approach described here should facilitate the study of bacterial genes that are required for biofilm formation. Those results, in turn, may provide insight into strategies to prevent pneumococcal colonization of its human host.

Topics: Amidohydrolases; Antigens, Bacterial; Bacterial Capsules; Bacterial Proteins; Biofilms; Carrier Proteins; Choline; DNA, Bacterial; Glass; Humans; Intracellular Signaling Peptides and Proteins; Muramidase; Mutation; N-Acetylmuramoyl-L-alanine Amidase; Pneumococcal Infections; Polystyrenes; Streptococcus pneumoniae; Teichoic Acids

We established a mouse model in which fatal pneumonia was induced by pneumococcal superinfection following influenza virus infection in chronic Pseudomonas aeruginosa infected mice. In this mouse model, influenza virus infection caused a significant increase in inflammatory cells, cytokines and severe tissue damage in the lungs of these P. aeruginosa infected mice, before pneumococcal infection. Intrapulmonary virus titres were significantly increased in mice with chronic P. aeruginosa infection, compared with control mice. Neutrophil function analysis showed significant reduction of myeloperoxidase (MPO) activity and lysozyme secretion by influenza virus infection in these mice. Our results suggest that influenza virus infection may play an important role in inducing pneumococcal pneumonia in chronic P. aeruginosa infected mice. Our results suggested that our mouse model is useful for investigating the pathogenesis of influenza virus infection in patients with chronic lung infection.

Topics: Acute Disease; Animals; Chronic Disease; Colony Count, Microbial; Cytokines; Disease Models, Animal; Disease Susceptibility; Lung; Lung Diseases, Parasitic; Male; Mice; Mice, Inbred Strains; Muramidase; Orthomyxoviridae Infections; Peroxidase; Pneumococcal Infections; Pneumonia, Pneumococcal; Pseudomonas Infections; Superinfection

The loss of spleen may increase the incidence of overwhelming sepsis. To prevent this, splenic autotransplantation has been performed in humans and experimental animals. However, there is still controversy about the effectiveness of regenerated splenic tissue in preventing infection. This study explored the effectiveness of splenic tissue autotransplantation in restoring host defense.. Rabbits were divided into three groups: splenic autotransplantation, sham operation, and total splenectomy. Histomorphology, T-lymphocyte count, serum lysozyme levels, hemolysin titers, and pneumococcal clearance were observed as read-out parameters over 24 weeks.. Histological study showed that the white pulp was poorly developed and central arterioles were missing in the regenerated splenic tissue of the autotransplanted rabbits. The weight of regenerated spleens recovered 6 months later in the splenic autotransplantation group was 11% of that in the sham operation group and was significantly less than the weight at implantation. There was no significant difference in the number of T lymphocytes or level of serum lysozyme between the three groups. A poor antibody response by the rabbits in the splenic autotransplantation and total splenectomy groups was noted after the primary intravenous administration of sheep red blood cells compared to those of sham operation group. After the challenge with type 3 pneumococci intravenously, pneumococcal clearance from the bloodstream in the splenic autotransplantation group did not differ significantly from that in the total splenectomy group, but was markedly delayed compared with that in the sham operation group.. The low quantity and poor quality of the regenerated splenic tissue contribute to the inferior immunoprotective ability of animals autotransplanted with one-third of the original spleen. This suggests that the regenerated spleen cannot compensate for the immunological function of the original one, especially host resistance to infection.

Topics: Animals; Disease Models, Animal; Immunity; Immunohistochemistry; Lymphocyte Count; Muramidase; Organ Transplantation; Pneumococcal Infections; Rabbits; Random Allocation; Reference Values; Regeneration; Sensitivity and Specificity; Sepsis; Spleen; Splenectomy; Survival Rate; Transplantation, Autologous; Treatment Outcome

Streptococcus pneumoniae is becoming increasingly antibiotic resistant worldwide, and thus new antimicrobials are badly needed. We report the use of Cpl-1, the lytic enzyme of a pneumococcal bacteriophage, as an intravenous therapy for pneumococcal bacteremia in a mouse model. A 2000- microg dose of Cpl-1 reduced pneumococcal titers from a median of log(10) 4.70 CFU/ml to undetectable levels (

Topics: Animals; Anti-Bacterial Agents; Bacteremia; Disease Models, Animal; Drug Resistance, Bacterial; Enzyme Stability; Female; Hydrogen-Ion Concentration; Mice; Mice, Inbred BALB C; Mice, Inbred C3H; Muramidase; Nasopharynx; Pneumococcal Infections; Streptococcus Phages; Streptococcus pneumoniae

Phage-coded lysins, i.e. murein hydrolases, are enzymes that destroy the cell wall of bacteria. A rapid killing of Streptococcus pneumoniae in the nasopharynx of mice has been described recently using a phage-coded murein hydrolase (enzybiotic). The in vivo effects of a dose-ranging treatment, using either of the phage-coded lytic enzymes Cpl-1 lysozyme or the Pal amidase, have been investigated here in a murine sepsis model.. Purified Pal amidase and/or Cpl-1 lysozyme were used alone or in combination. These enzymes were injected intraperitoneally at different times after challenge with 5 x 10(7) cfu of a type 6B, antibiotic-resistant S. pneumoniae clinical isolate.. Animals challenged with 5 x 10(7) cfu of this strain alone died within 72 h, whereas a single intraperitoneal injection of Cpl-1 or Pal (200 microg; 1100 U) administered 1 h after the bacterial challenge was sufficient to effectively protect the mice, according to unpaired t-test (P<0.0001). Bacteraemia in unprotected mice reached colony counts >10(7) cfu/mL, whereas the mean colony count in lysin-protected animals was <10(6) cfu/mL over time and ultimately became undetectable. Interestingly, a synergic effect in vivo was observed with the combined use of 2.5 microg each of Cpl-1 and Pal.. Our findings suggest strongly that phage lysins protect animals from bacteraemia and death. Moreover, the simultaneous attack of the pneumococcal peptidoglycan by a lysozyme and an amidase leads to a remarkable effect through enhanced destruction of the bacterial cell wall. The benefits of therapy with enzybiotics against pneumococcus reported here might warrant the examination of alternative strategies for the treatment of diseases caused by clinically relevant pathogens.

Topics: Amidohydrolases; Animals; Anti-Bacterial Agents; Antibodies, Bacterial; Bacteremia; Bacteriophages; Blotting, Western; Cell Wall; Chromatography, DEAE-Cellulose; Drug Resistance, Bacterial; Drug Synergism; Female; Mice; Mice, Inbred BALB C; Muramidase; Pneumococcal Infections

Many glucosamine residues of the pneumococcal peptidoglycan (PG) are not acetylated, which makes the PG resistant to lysozyme. A capsular type III mutant with an inactivated pgdA gene (encoding the peptidoglycan N-acetylglucosamine deacetylase A) became hypersensitive to exogenous lysozyme and showed reduced virulence in the intraperitoneal mouse model.

Topics: Amidohydrolases; Animals; Bacterial Proteins; Disease Models, Animal; Humans; Mice; Muramidase; Mutation; Pneumococcal Infections; Streptococcus pneumoniae; Virulence

N-acetylmuramyl-L-alanine amidase (NAMLAA) specifically degrades peptidoglycan, a major component of bacterial cell walls. Lysozyme degrades peptidoglycan differently by hydrolyzing the aminosugar backbone of peptidoglycan. In another study, it was shown that the two enzymes act synergistically to inactivate the inflammatory properties of peptidoglycan. The presence of lysozyme and NAMLAA was determined in serum and cerebrospinal fluid (CSF) of patients with bacterial meningitis. High concentrations of lysozyme were found in CSF while, surprisingly, NAMLAA was not present. To explain this phenomenon, the degranulation pattern of neutrophils in CSF was compared with that of neutrophils from blood. Specific granules contain lysozyme and the azurophil granules contain both lysozyme and NAMLAA. CD66b expression on the cell surface, indicative for fusion of the specific granules with the cell membrane, was higher in CSF than in blood, while the marker for the azurophil granules was lower.

Topics: Adolescent; Adult; Aged; Antigens, CD; Antigens, Neoplasm; Cell Adhesion Molecules; Cell Degranulation; Cell Membrane; Child; Child, Preschool; Female; Flow Cytometry; GPI-Linked Proteins; Haemophilus Infections; Humans; Infant; Male; Membrane Glycoproteins; Meningitis, Bacterial; Meningitis, Meningococcal; Middle Aged; Muramidase; N-Acetylmuramoyl-L-alanine Amidase; Neutrophil Activation; Neutrophils; Pneumococcal Infections

Lysozyme had no effect on the rate of multiplication of growing cultures of Streptococcus pneumoniae, but it greatly reduced the lag period that precedes autolysis of these bacteria in stationary phase. Several experiments were done to understand the mechanism of this effect. Lysozyme had no hydrolytic activity on intact cell walls, and cell walls of pneumococci grown with or without lysozyme had identical composition and susceptibility to the pneumococcal autolysin. The acceleration of stationary-phase autolysis by lysozyme involved triggering of the pneumococcal autolytic enzyme since lysozyme had no detectable effect on nonautolysing (LytA-) mutants and heat-inactivated lysozyme completely lacking enzymatic activity was as effective as the nondenatured enzyme in facilitating stationary-phase autolysis. The role of lysozyme in host defense against pneumococcal infection remains elusive.

Topics: Animals; Bacteriolysis; Cell Wall; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Hot Temperature; In Vitro Techniques; Muramidase; N-Acetylmuramoyl-L-alanine Amidase; Peptides; Peptidoglycan; Pneumococcal Infections; Rabbits; Streptococcus pneumoniae; Time Factors

Most Streptococcus pneumoniae strains are killed by very low concentrations of penicillin and other beta-lactam antibiotics, yet middle ear inflammation and effusion persist for days to weeks after treatment in most cases of pneumococcal otitis media. To study the effect of beta-lactam antibiotic treatment on pneumococci and the middle ear inflammatory response during pneumococcal otitis media, we measured concentrations of pneumococci, inflammatory cells, and lysozyme in middle ear fluid (MEF) by using the chinchilla model. Procaine penicillin G given intramuscularly 12 and 36 h after inoculation of pneumococci into the middle ear caused a significant acceleration in the MEF inflammatory cell concentration compared with that in untreated controls, with a significant peak in the inflammatory cell concentration 24 h after pneumococcal inoculation. The lysozyme concentration in MEF also increased more rapidly in treated than in control animals. Viable pneumococci were not detected in MEF after the second dose of penicillin, but the total pneumococcal cell concentration remained unchanged for at least 45 days. Therefore, penicillin treatment accelerated middle ear inflammation while killing pneumococci, but treatment did not accelerate clearance of the nonviable pneumococcal cells from MEF. Further studies will need to define the contribution of these responses to acute and chronic tissue injury.

Topics: Animals; Chinchilla; Muramidase; Otitis Media; Penicillins; Pneumococcal Infections

Middle ear infection with Streptococcus pneumoniae is important in the pathogenesis of acute and chronic otitis media, and lysozyme in middle ear fluid (MEF) is an important inflammatory mediator in this disease. To determine the source of lysozyme during the early period of acute pneumococcal otitis media, chinchillas were irradiated to induce neutropenia, and their middle ears were inoculated with heat-killed, encapsulated pneumococci. The number of inflammatory cells and concentration of lysozyme were measured in MEF between 6 and 72 hours after inoculation. In pneumococcus-inoculated ears, the mean number of inflammatory cells but not lysozyme was significantly lower in MEF from irradiated animals than that from nonirradiated animals at 6 hours. Since lysozyme accumulated in MEF before the influx of inflammatory cells in irradiated animals, the initial release of this inflammatory mediator is most likely not from inflammatory cells; and mucosal epithelial cells, the only other known source of lysozyme in the middle ear environment, were the probable source induced by the direct stimulation of pneumococci. Inflammatory cells may contribute lysozyme later in the inflammatory response, since cellular and lysozyme concentrations in irradiated and nonirradiated animals were similar between 24 and 72 hours. These results suggest that future therapeutic interventions to limit middle ear inflammation in acute otitis media may need to recognize the direct action of pneumococcal cells or their envelope components on middle ear epithelium.

Topics: Acute Disease; Animals; Chinchilla; Leukocyte Count; Muramidase; Otitis Media with Effusion; Pneumococcal Infections

Pulmonary clearance of inhaled pneumococci is markedly impaired in neonatal rats compared with that in adult rats. To determine whether this impairment is due to a deficiency of extracellular bactericidal factors, the antipneumococcal activity of free fatty acids (FFA) in lung surfactant and the levels of lysozyme and transferrin in lavage fluids were quantified. Surfactant from adult rats averaged 68 U of antipneumococcal activity per g (dry weight) of lung, compared with less than 0.25 U for rats less than 1 week old (P less than 0.001). The kinds of FFA in surfactant of neonatal and adult rats were essentially identical, and the antipneumococcal activity of highly purified FFA from surfactant of neonatal and adult rats was also the same. However, the quantity of FFA in surfactant varied significantly with age, and rats less than 3 weeks old had much lower levels of surfactant FFA than did adults (P less than 0.001). In addition, lavage fluids from neonatal rats inhibited the antipneumococcal activity of surfactant FFA more than lavage fluids from adults did (P less than 0.02). This inhibitory activity did not appear to be due to protein binding. Lavage fluids from neonates showed an age-related deficiency of lysozyme (P less than 0.001), but lysozyme appeared to play no role in pneumococcal killing by the surfactant fraction of lavage fluids in vitro. Transferrin levels in lavage fluids were similar for neonates and adults. It was concluded that lung surfactant from neonatal rats was deficient in antipneumococcal activity, due mostly to low levels of FFA and to a lesser degree to increased levels of inhibitor(s) in lavage fluids.

Topics: Aging; Animals; Animals, Newborn; Anti-Infective Agents; Bronchoalveolar Lavage Fluid; Fatty Acids, Nonesterified; Muramidase; Pneumococcal Infections; Pulmonary Surfactants; Rats; Rats, Inbred Strains; Transferrin

The sequential cytologic and biochemical events of middle ear effusion (MEE) were studied in experimental models of serous otitis media (SOM) and purulent otitis media (POM) in chinchilla. In the SOM model, the initial appearance of neutrophils was followed by macrophages. In the POM model, neutrophils were the predominant cells in MEE and the number of neutrophils was about 100-fold higher than in the SOM model. The activity of lysozyme in MEE was higher in POM than in SOM and correlated with the number of neutrophils and mononuclear phagocytes. The results of the present study suggest that neutrophils and mononuclear phagocytes are one of the main sources for lysozyme levels in MEE during otitis media.

Topics: Animals; Chinchilla; Muramidase; Otitis Media; Otitis Media with Effusion; Otitis Media, Suppurative; Pneumococcal Infections; Time Factors

Examination of 329 pneumococcal strains showed that 41.2 per cent of the cultures had lysozyme activity. The frequency of the lysozyme feature depended on the method used. The lysozyme active strains were more frequently isolated from patients than from healthy persons and characterized by antibiotic resistance. The lysozyme feature correlated with the pneumococcal virulence with respect to albino mice, capacity for capsule formaiton and resistance to phagocytosis.

Topics: Animals; Anti-Bacterial Agents; Drug Resistance, Microbial; Ecology; Enzyme Activation; Mice; Muramidase; Phagocytosis; Pneumococcal Infections; Streptococcus pneumoniae; Virulence

The changes in intraneutrophilic and plasma concentrations of the three antibacterial proteins lysozyme, lactoferrin, and myeloperoxidase were studied sequentially during acute bacterial infection in nine patients. Intraneutrophilic concentrations of the three proteins were decreased by more than 50% during the 1st week of infection, followed by a slow increase over the following 2 weeks. Nadir values coincided with maximal toxic granulation of the neutrophils. The data suggest that neutrophilic granulocytes are deficient during early bacterial infection, possibly because of deficient synthesis of antibacterial proteins in the bone marrow, and that neutrophil toxic granulation is the visual counterpart of this defect. The plasma concentrations of the three proteins showed considerable differences: whereas plasma lysozyme did not show any sequential changes, plasma myeloperoxidase was high at the start of infection and quickly decreased towards normal values, and plasma lactoferrin, high in the first samples, showed a secondary peak 1 week after onset of disease, before normalization was seen. These differences may result from differences in the signals are specific for the individual antibacterial protein and not for the different types of neutrophil granules.

Topics: Adult; Aged; Bacterial Infections; Blood Bactericidal Activity; Humans; Lactoferrin; Lactoglobulins; Meningitis; Middle Aged; Muramidase; Neutrophils; Peroxidase; Peroxidases; Pneumococcal Infections; Time Factors

Topics: Bacteriological Techniques; Conjunctivitis; Enterobacteriaceae Infections; Humans; Moraxella; Muramidase; Pneumococcal Infections; Proteus Infections; Staphylococcal Infections; Streptococcal Infections

Topics: Animals; Clostridium Infections; Clostridium tetani; Drug Synergism; Female; Male; Mice; Microbial Sensitivity Tests; Muramidase; Penicillins; Placenta; Pneumococcal Infections; Pregnancy; Staphylococcal Infections; Staphylococcus; Streptococcus pneumoniae

Topics: Animals; Anti-Bacterial Agents; Bacteria; Drug Resistance, Microbial; Drug Synergism; Mice; Muramidase; Pneumococcal Infections; Staphylococcus