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PubMed1989

Nasopharyngeal culture with quantitative analysis of pathogenes in chronic otitis media with effusion. Effects on pathogen yield of different swabs and transport methods.

The influence of different swabs and transport media on nasopharyngeal culture pathogen recovery has been studied in patients with chronic otitis media with effusion. Transport times of less than two hours have been used. Protecting the cotton wire swab with a polyethylene shealth to prevent contamination by nasal flora did not have any significant influence either on the recovery of potential pathogens or on the contaminating nasal flora. Facilitating a quantitative analysis of the nasopharyngeal culture by transporting the specimen in empty tubes gave a pathogen recovery rate similar to that with transport in Stuart medium, whereas an attempt at transporting in sodium chloride or prereduced PY broth led to significantly lower yields of Branhamella catarrhalis (p less than 0.01) and in PY broth on Haemophilus influenzae as well (p less than 0.01).

Child, Preschool↗
PubMed2006

[Reasons for recurrent respiratory tract inflammations in children].

Respiratory tract inflammations are among the most frequent diseases in children. In natural conditions, respiratory tract is constantly prone to environmental pathogens. In fighting the respiratory tract infections both non-specific and specific: humoral and cellular immune mechanisms, related to mucosa-associated lymphoid tissue (MALT), take part. In healthy subjects, the upper respiratory tract is affluent in physiological bacterial flora comprising aerobic and anaerobic bacteria, some of them potentially pathogenic. In periods of reduced immunity they can cause endogenous infections. Contrary to the upper, the lower respiratory ways are physiologically sterile. The imbalance between defense mechanisms and pathogenity of microorganisms can lead to the development of infection. Recurrent respiratory tract inflammations, due to complexity of their causes, are a problem of great importance. Early estimation of the etiology of recurrent inflammations is particularly crucial, as it allows introduction of aimed therapy and prophylactics, thus preventing the child from the development of irreversible pulmonary lesions and impairment of physical development.

Child↗
PubMed1997

Metallothioneins in brain--the role in physiology and pathology.

A symposium on the role of brain metallothioneins (MTs) in physiology and pathology was held at the 1996 Annual Society of Toxicology Meeting in Anaheim, California. The objectives of this symposium were to: (1) review the physiologic function of MTs, (2) examine the distribution of brain MTs with particular emphasis on cell-specific localization (neurons vs neuroglia), (3) discuss MT gene responsiveness upon toxic insult with metals, and (4) discuss the potential role of MTs in the etiology of neurodegenerative disorders. Dr. Cherian discussed the biochemical properties of the MTs, emphasizing structural similarities and differences between the MTs. Dr. Klaassen addressed the expression and distribution of the MTs in brains with special reference to the cell-specific localization of MTs. Dr. Aschner provided data illustrating a potential role for MTs in attenuating the cytotoxicity caused by methylmercury (MeHg) in cultured neonatal astrocytes. Dr. Palmiter discussed the properties of MT-III and the increased sensitivity of MT-III knockout mice to kainate-induced seizures. Cerebral zinc metabolism, its relationship to MT homeostasis, and its pathogenic potential in Alzheimer's disease was addressed by Dr. Bush.

Animals↗
PubMed2001

Composting of solid and sludge residues from agricultural and food industries. Bioindicators of monitoring and compost maturity.

A study to monitor the composting process, to evaluate the effectiveness of bioindicators for the quality and maturity of cured compost obtained by a mixture of winery residues, sludges from dairies and solid residues from food processing (grape-stalks, grape-dregs, rice husks), was conducted. Composting process lasting five months was monitored by chemico-physical, spectroscopic (FTIR, DTG and DSC), microbiological and enzymatic analyses. Biological activities (ATP, DHA contents and several enzymatic activities), impedance variations (DT) of mixed cultures during growth and potential pathogens (E. coli and Salmonella sp.), were determined. The phytotoxicity tests gave a germination index higher than 90% and no significant genotoxic differences between controls and the compost samples were evidenced. Pathogens were not found on the cured compost that can therefore be satisfactorily used as amendment for agricultural crops. However, no single measurement of a composting process factor, biological, chemical or physical, gave a comprehensive view of the quality of a specific composting. We proposed a tool of bioindicators of potential activity and markers in combination for integrated evaluation of monitoring of composting process and compost quality. The responses of several enzymatic activities were positive and indicative of their favorable use capable to reveal even very small changes within microbial population and activity in test and monitoring of compost programmes.

Agriculture↗
PubMed2006

Malignant hyperthermia in Japan: mutation screening of the entire ryanodine receptor type 1 gene coding region by direct sequencing.

BACKGROUND: Malignant hyperthermia (MH) is a disorder of calcium homeostasis in skeletal muscle triggered by volatile anesthetics or succinylcholine in susceptible persons. More than 100 mutations in the ryanodine receptor type 1 gene (RYR1) have been associated with MH susceptibility, central core disease, or both. RYR1 mutations may account for up to 70% of MH-susceptible cases. The authors aimed to determine the frequency and distribution of RYR1 mutations in the Japanese MH-susceptible population. METHODS: The authors selected 58 unrelated Japanese diagnosed as MH-susceptible for having an enhanced Ca-induced Ca release rate from the sarcoplasmic reticulum on chemically skinned muscle fibers. They sequenced the entire RYR1 coding region from genomic DNA. Muscle pathology was also characterized. RESULTS: Seven previously reported and 26 unknown RYR1 potentially pathogenic sequence variations were identified in 33 patients (56.9%). Of these patients, 48% had cores on muscle biopsy. The mutation detection rate was higher in patients with clear enhancement of Ca-induced Ca release rate (72.4%), whereas all patients with central core disease had RYR1 mutations. Six patients harbored potentially causative compound heterozygous sequence variations. CONCLUSIONS: Distribution and frequency of RYR1 mutations differed markedly from those of the North American and European MH-susceptible population. Comprehensive screening of the RYR1 gene is recommended for molecular investigations in MH-susceptible individuals, because many mutations are located outside the "hot spots." Based on the observed occurrence of compound heterozygous state, the prevalence of a possibly predisposing phenotype in the Japanese population might be as high as 1 in 2,000 people.

Adolescent↗
PubMed1998

Effect of IgA1 protease on the ability of secretory IgA1 antibodies to inhibit the adherence of Streptococcus mutans.

Secretory IgA (SIgA) is the principal immunoglobulin isotype present in the mucosal secretions of humans. SIgA is thought to play a major role in host defense at these surfaces by inhibiting the colonization of potentially pathogenic microorganisms. A number of bacteria that are mucosal pathogens of humans produce a protease that specifically cleaves the IgA1 subclass of humans and great apes at the hinge region to produce Fab and Fc fragments. In order to study the effect of IgA1 protease on the ability of SIgA1 antibodies to inhibit bacterial adherence, an in vitro assay that quantifies the adsorption of radiolabeled Streptococcus mutans to hydroxyapatite (HA) beads was employed. High titer S. mutans-specific SIgA1 and SIgA2 antibodies were induced in chimpanzee milk for use in the assay. Fab alpha1 fragments had significantly reduced ability to inhibit adherence of S. mutans to saliva-coated HA compared to intact SIgA1 or SIgA2 anti-S. mutans antibodies. These data support the potential importance of IgA1 proteases as an ecological determinant in the oral cavity and their role as a determinant of pathogenesis of pathogenic bacteria whose portal of entry is the mucosal surface.

Animals↗
PubMedDate not supplied

Mycoplasma hominis: a placental pathogen?

Current information on the role played by Mycoplasma hominis in placental inflammation was reviewed. M. hominis is associated with chorioamnionitis and funisitis, but the clinical significance of this association in not clear. Further research on the role of the organism in perinatal disease is needed. Meanwhile, in a gravely ill infant with a history of prolonged rupture of the placental membranes, chorioamnionitis, and funisitis, M. hominis should probably be considered a potential pathogen, cultures for this organism should be performed, and therapy with an antibiotic regimen effective against M. hominis should be instituted.

Amnion↗
PubMed1997

Human herpesvirus-6 infection in liver transplant recipients: documentation of pathogenicity.

BACKGROUND: The new herpesvirus, human herpesvirus-6 (HHV-6), is able to cause clinical illness after transplantation; however, the pathogenic potential and the clinical features of HHV-6 have not been defined in liver transplant recipients. METHODS: We report the first cases of invasive and symptomatic infection due to HHV-6 in liver transplant recipients. RESULTS: HHV-6 infection occurred in four liver transplant recipients at a median of 50 days after transplant (range 17-90 days). Severe cytopenia was observed in all patients; leukopenia (with median leukocyte count of 1400/mm3) was the most commonly effected bone marrow lineage. One of the four patients had interstitial pneumonitis due to HHV-6. No other virus (e.g., cytomegalovirus) or another pathogen was detected in the lungs, blood, or bone marrow in any of the above patients. CONCLUSIONS: Our data suggest that HHV-6 can be a pathogen in liver transplant recipients; idiopathic bone marrow suppression is its predominant clinical sequelae. Recognition of HHV-6 infection is clinically pertinent because HHV-6 is potentially treatable with the currently available antiviral agents.

Adult↗
PubMed1992

Pyrazinamidase, CR-MOX agar, salicin fermentation-esculin hydrolysis, and D-xylose fermentation for identifying pathogenic serotypes of Yersinia enterocolitica.

We evaluated several simple laboratory tests that have been used to identify pathogenic serotypes of Yersinia enterocolitica or to indicate the pathogenic potential of individual strains. A total of 100 strains of Y. enterocolitica were studied, including 25 isolated during five outbreak investigations, 63 from sporadic cases, and 12 from stock cultures. The pyrazinamidase test, which does not depend on the Yersinia virulence plasmid, correctly identified 60 of 63 (95% sensitivity) strains of pathogenic serotypes and 34 of 37 (92% specificity) strains of nonpathogenic serotypes. Salicin fermentation-esculin hydrolysis (25 degrees C, 48 h) correctly identified all 63 (100% sensitivity) strains of the pathogenic serotypes and 34 of 37 (92% specificity) strains of the nonpathogenic serotypes. The results of the pyrazinamidase and salicin-esculin tests disagreed for only 7 of the 100 strains of Y. enterocolitica, and these would require additional testing. Congo red-magnesium oxalate (CR-MOX) agar determines Congo red dye uptake and calcium-dependent growth at 36 degrees C, and small red colonies are present only if the strain contains the Yersinia virulence plasmid. This test has proven to be extremely useful for freshly isolated cultures, but only 15 of 62 strains of pathogenic serotypes that had been stored for 1 to 10 years were CR-MOX positive. None of the 16 strains of Y. enterocolitica serotype O3 fermented D-xylose, so this test easily differentiated strains of this serotype, which now appears to be the most common in the United States. Although antisera that can actually be used to serotype strains of Y. enterocolitica are not readily available, the four simple tests described above can be used to screen for pathogenic serotypes.

Agar↗
PubMed1987

Relapse of acute purulent otitis media: antibiotic sensitivities of nasopharyngeal pathogens.

The present investigation was conducted to find out if a relapse of acute purulent otitis media is associated with a decreased sensitivity of nasopharyngeal pathogens to commonly used antimicrobial agents. All but one of 63 children with relapse included in this study yielded one or more of the classical middle ear pathogens (Streptococcus pneumoniae, Haemophilus influenzae, Branhamella catarrhalis, S. pyogenes) in their nasopharynx (NPH) secretions. S. pneumoniae was the predominating isolate from NPH (71% of the patients) as well as from middle ear effusion (53%). At a control visit 4 weeks after the start of antibiotic therapy, 91% were NPH carriers of potential pathogens and S. pneumoniae was still the most common isolate (53%). Beta-lactamase was produced by 55% of B. catarrhalis isolates from the NPH specimens on the first visit, but only by 33% of B. catarrhalis isolates on the control visit. Two NPH isolates of H. influenzae produced beta-lactamase. One isolate of S. pneumoniae (serotype 18) was intermediately sensitive to phenoxymethylpenicillin. Generally low MICs were found for erythromycin and cefaclor. H. influenzae isolates were generally sensitive to ampicillin in vitro, but only 1 isolate was fully sensitive to erythromycin. B. catarrhalis isolates were uniformly sensitive to doxycycline and trimethoprim/sulphamethoxazole. No tolerance to penicillin was demonstrated in S. pneumoniae and H. influenzae. The present data indicate that the relapse of acute otitis media is not associated with development of tolerance or resistance to therapeutic antimicrobials commonly used.

Acute Disease↗
PubMed1990

The role of bacterial vaginosis as a cause of amniotic fluid infection, chorioamnionitis and prematurity--a review.

Antepartum bacterial vaginosis in pregnancy has been related to premature delivery, the recovery of microorganisms from amniotic fluid of women in premature labor with intact membranes, to histologic chorioamnionitis and to the recovery of microorganisms from the placenta or membranes. Microorganisms associated with bacterial vaginosis are commonly recovered from the amniotic fluid and chorioamnion of patients who deliver prematurely. In addition, bacterial vaginosis is associated with maternal infectious morbidity during labor and in the postpartum period. Very little is known of the pathophysiologic mechanisms by which bacterial vaginosis may cause preterm labor and/or premature rupture of the membranes. However, it is of interest to speculate on possible mechanisms. The high concentration of potentially pathogenic microorganisms in the vagina and cervix of pregnant women with bacterial vaginosis may increase the possibility of an ascending infection via the cervix, decidua, fetal membranes, maternal placenta, and amniotic fluid. Some of the bacteria associated with bacterial vaginosis such as Bacteroides sp. are particularly virulent. Certain bacteria produce enzymes that potentially could affect the fetal membranes or maternal deciduae. Bacteroides sp. and group B streptococcus produce proteases. Protease enzymes reduce the chorioamniotic membrane strength in vitro. It is even possible that a high concentration of bacteria in the lower genital tract could produce enough proteases to weaken the fetal membrane strength causing premature rupture of the membranes. Bacterial lipases could also produce tissue injury. Schwarz et al. demonstrated that lysosomes within fetal membrane cells contain phospholipase A2 in high concentrations. Phospholipase A2 is a precursor of prostaglandin synthesis and the destruction of lysosomes within deciduae or chorioamnion cells may induce prostaglandin synthesis resulting in uterine contractions. Bejar et al. found a high rate of phospholipase A2 production by Bacteroides sp., anaerobic streptococci, Fusobacterium sp., and G. vaginalis. Benett et al. demonstrated that bacterial products of group B streptococci, viridans streptococci, Escherichia coli and Bacteroides fragilis but not of Lactobacillus sp. increase the synthesis of prostaglandins in the membranes. Thus, selected bacteria, including some closely related to bacterial vaginosis may play a role in the initiation of uterine contractions by stimulating prostaglandin synthesis. In an alternative mechanism, either the release of prostaglandin in the membrane or uterine contraction could cause microbreaks of the membrane that allow bacterial colonization of the membrane.(ABSTRACT TRUNCATED AT 400 WORDS)

Amniotic Fluid↗
PubMed1999

Implications of endotracheal tube biofilm for ventilator-associated pneumonia.

OBJECTIVE: To determine the relationship between, and antibiotic resistance of, endotracheal tube (ET) biofilm and pulmonary pathogens in ventilator-associated pneumonia (VAP). SETTING: General intensive care units in two university teaching hospitals. DESIGN: The microbiology of ET biofilm and tracheal samples from patients with and without VAP were compared. For individual patients, matching pairs of pathogens were confirmed as identical and characterised for antibiotic susceptibility. PATIENTS: 40 intensive care unit patients - 20 with VAP, 20 without VAP as control. The duration of intubation (median and range) was 6.5 days (3-17) and 5 days (2-10), respectively. MEASUREMENTS AND RESULTS: Samples of tracheal secretions were taken during ventilation for bacteriological culture. Following extubation, ETs were examined for the presence of biofilm. Isolates of high pathogenic potential included Staphylococcus aureus, enterococci, Enterobacteriaceae, pseudomonads and Candida spp. Where the same microorganism was found on tracheal and ET samples by phenotyping, these were confirmed as identical by genotyping and characterised for antibiotic susceptibility in both the free floating and biofilm forms. Seventy per cent of patients with VAP had identical pathogens isolated from both ET biofilm and tracheal secretions. No pairing of pathogens was observed in control patients (p < 0.005). Susceptibility data for these pairs show that the ET acts as a reservoir for infecting microorganisms which exhibit significantly greater antibiotic resistance than their tracheal counterparts. CONCLUSION: This investigation provides further evidence for the role of ET biofilm in VAP. The difficulty in eradicating an established microbial biofilm using antibiotics implies that increased attention must be directed towards modification of the ET to prevent or substantially reduce biofilm formation.

Adolescent↗
PubMed2006

Hormonal regulation of placental nitric oxide and pathogenesis of pre-eclampsia.

The placenta is central to foetal growth and development in mammalian pregnancy. Compromised placental function (as found in pre-eclampsia) often results in life-threatening situations for both mother and foetus. The nitric-oxide (NO) signalling cascade is important for placental function, in particular for the development of the vascular network and for maintaining vascular tone. This pathway seems to be regulated by multiple hormonal signals. Emerging evidence suggests that pathogenic mechanisms that are involved in abnormal placental function target specific molecules, such as hormone receptors, that regulate NO release and have subsequent dramatic consequences. Here, we discuss the current knowledge of NO function in the placenta, its hormonal regulation in normal pregnancy and in the pathophysiology of pre-eclampsia, its potential pathogenic mechanisms and possible use as a therapeutic target.

Animals↗
PubMed2001

Serine proteases as mediators of mosquito immune responses.

Serine proteases regulate several invertebrate defense responses, including hemolymph coagulation, antimicrobial peptide synthesis, and melanization of pathogen surfaces. These processes require the presence of serine proteases in the hemolymph where they can rapidly activate immune pathways in response to pathogen detection. Hemolymph coagulation in the horseshoe crab is controlled by several serine proteases, including two that are pathogen recognition molecules and two in the clip domain family of serine proteases. The antimicrobial peptide synthesis and melanization pathways include clip domain proteases as well as other, uncharacterized serine proteases. We have identified five serine proteases from the hemolymph of the mosquito, Anopheles gambiae. One, Sp22D, is a large protease with potential pathogen binding domains. Sp22D is expressed in three tissues that have immune functions (midgut epithelium, fat body, and hemocytes), and its transcript abundance increases after immune challenge. Sp14A, Sp14D1, and Sp14D2 are clip domain serine proteases that are similar to enzymes with presumed roles in melanization or antimicrobial peptide synthesis. They undergo changes in transcript abundance in response to infection with bacteria or malaria parasites, and they reside in a chromosomal region that has been associated with melanization of parasites. Sp18D, also a clip domain protease, is similar to a Manduca protease with a likely role in immunity, but immune challenge does not affect its mRNA abundance.

Amino Acid Sequence↗
PubMed1988

Virulence of Yersinia pseudotuberculosis isolated from pork and from the throats of swine.

Yersinia pseudotuberculosis was isolated from retail pork and from healthy swine throats. These wild-type strains and their representative cured isogenic strains were tested for the presence of plasmids and several virulence factors, and these characteristics were compared with those of virulent strains from humans. Two pork isolates (serotype IVB) and four swine isolates (serotypes IIB, IIC, III, and IVB) harbored a 42- to 48-megadalton plasmid which had similar fragmentation patterns resulting from digestion with restriction endonuclease. These six strains were lethal for mice via oral challenge and were positive in autoagglutination and calcium dependency tests. They also invaded HeLa cells and induced cytotoxicity. Histopathological examination and indirect fluorescent-antibody staining provided definite evidence of the pathogenicity of these strains when tissue sections from orally infected mice were used. The virulence factors of wild-type pork and swine isolates with the 42- to 48-megadalton plasmid were identical to those of two human isolates (serotypes IVB and VB). Hence, these pork and swine isolates should be considered potentially pathogenic for humans. The finding suggests that retail pork and swine may play an important role in the epidemiology of human infections caused by Y. pseudotuberculosis.

Agglutination Tests↗
PubMed2005

Protection of mice against lethal infection with highly pathogenic H7N7 influenza A virus by using a recombinant low-pathogenicity vaccine strain.

In 2003, an outbreak of highly pathogenic avian influenza occurred in The Netherlands. The avian H7N7 virus causing the outbreak was also detected in 88 humans suffering from conjunctivitis or mild respiratory symptoms and one person who died of pneumonia and acute respiratory distress syndrome. Here we describe a mouse model for lethal infection with A/Netherlands/219/03 isolated from the fatal case. Because of the zoonotic and pathogenic potential of the H7N7 virus, a candidate vaccine carrying the avian hemagglutinin and neuraminidase proteins produced in the context of the high-throughput vaccine strain A/PR/8/34 was generated by reverse genetics and tested in the mouse model. The hemagglutinin gene of the recombinant vaccine strain was derived from a low-pathogenicity virus obtained prior to the outbreak from a wild mallard. The efficacy of a classical nonadjuvanted subunit vaccine and an immune stimulatory complex-adjuvanted vaccine was compared. Mice receiving the nonadjuvanted vaccine revealed low antibody titers, lack of clinical protection, high virus titers in the lungs, and presence of virus in the spleen, liver, kidneys, and brain. In contrast, mice receiving two doses of the immune stimulatory complex-adjuvanted vaccine revealed high antibody titers, clinical protection, approximately 1,000-fold reduction of virus titers in the lungs, and rare detection of the virus in other organs. This is the first report of an H7 vaccine candidate tested in a mammalian model. The data presented suggest that vaccine candidates based on low-pathogenicity avian influenza A viruses, which can be prepared ahead of pandemic threats, can be efficacious if an effective adjuvant is used.

Adjuvants, Immunologic↗
PubMed2000

Diagnosis and treatment of opportunistic infections in immunocompromised surgical patients.

The advent of successful therapy for patients who suffer many types of organ dysfunction and failure, malignancies, and acquired immunodeficiency syndrome has led to the concurrent threat of infection due to a wide array of pathogens, particularly opportunistic microbes that rarely cause disease under routine circumstances. Among patients who are subjected to extreme degrees of immunosuppression, almost any type of bacterial, fungal, viral, protozoal, or parasitic organism can exhibit pathogenic potential and lead to devastating consequences for the host. Immunosuppressive drug therapy for the purpose of organ allograft maintenance, cancer chemotherapy, or the human immunodeficiency virus exerts potent effects upon cellular immunity. Therefore, although these groups of patients are more susceptible to all types of infectious disease processes, infections due to those pathogens that require a component of cellular immunity for their eradication, such as fungi and viruses, occur at a higher frequency than that observed among normal individuals. Of critical importance, all types of infections are associated with higher rates of morbidity and mortality in immunosuppressed patients. Currently, improved diagnostic techniques and new treatment modalities have rendered many serious infections, for which suitable therapy previously did not exist, amenable to treatment. Because of the large number of immunosuppressed patients who now lead highly productive lives, it is important for the surgical practitioner to become familiar with the modalities currently available to precisely diagnose and effectively treat opportunistic infections in immunocompromised surgical patients.

Bacterial Infections↗
PubMed2004

In vitro activities of 3-(halogenated phenyl)-5-acyloxymethyl- 2,5-dihydrofuran-2-ones against common and emerging yeasts and molds.

Three 3-(halogenated phenyl)-5-acyloxymethyl-2,5-dihydrofuran-2-ones were evaluated for activity against 191 strains of common and emerging yeasts and Aspergillus species by the broth microdilution test performed according to NCCLS guidelines. The furanone derivatives displayed broad-spectrum in vitro activity against potentially pathogenic yeasts and molds, especially Aspergillus spp. (MIC <or= 2.0 microg/ml) and fluconazole-resistant yeast isolates, including Candida glabrata and Saccharomyces cerevisiae. The 4-bromophenyl derivative was the most effective derivative against the majority of species tested, except for the Candida tropicalis and C. glabrata strains, which were more susceptible to the 3-chlorophenyl derivative. The 3,4-dichlorophenyl derivative possessed a lesser in vitro antifungal effect. The potential of further experiments on animal infection and clinical studies is supported by the relatively low cytotoxicity and acute toxicity of the 4-bromophenyl compound. Thus, the halogenated 3-phenyl-5-acyloxymethyl derivatives of 2,5-dihydrofuran-2-one represent a novel, promising group of compounds with significant activity against relevant opportunistic fungi that are pathogenic to humans.

Animals↗