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PubMed2005

Bronchial colonization and postoperative respiratory infections in patients undergoing lung cancer surgery.

STUDY OBJECTIVES: To evaluate the risk factors associated with postoperative respiratory infection in patients undergoing lung cancer surgery, with special emphasis on the perioperative pattern of airway colonization. DESIGN: Prospective cohort study. SETTING: Department of Pneumology and Thoracic Surgery of a tertiary hospital. PATIENTS: Seventy-eight consecutive patients undergoing lung cancer surgery were evaluated. Patients were followed up until hospital discharge or death. INTERVENTIONS: Fiberoptic bronchoscopies with bilateral protected specimen brush or bronchial aspirates were performed during anesthesia prior to the initiation of the surgical procedure. RESULTS: Sixty-five patients (83%) had perioperative bronchial colonization by either potentially pathogenic microorganisms (PPMs) [28 patients, 36%] or non-potentially pathogenic microorganisms (56 patients, 72%). The 24 patients (31%) with a postoperative respiratory infection (pneumonia, purulent tracheobronchitis, or pleural empyema) had significantly higher perioperative bronchial colonization by PPMs (15 patients [63%] vs 13 patients [24%], p = 0.003) and a higher bacterial index (mean +/- SD, 3.6 +/- 3.3 vs 0.9 +/- 1.4; p = 0.003), compared to patients without infection. The agreement between pathogens found in perioperative evaluation and during postoperative infection was total in 5 patients (21%), partial in 5 patients (21%), and no concordance in 14 patients (58%). In the multivariate analysis, the presence of perioperative airway colonization by a PPM (odds ratio [OR], 6.9; p = 0.001) and a higher postoperative pain score (OR, 4.1; p = 0.014) were independent predictors of postoperative respiratory infection. CONCLUSION: Adequate control of postoperative pain, as well as the conditions that potentially cause airway colonization by PPMs, could be beneficial in preventing postoperative respiratory infections after lung cancer surgery.

Aged↗
PubMed1988

Entamoeba histolytica: virulence potential and sensitivity to metronidazole and emetine of four isolates possessing nonpathogenic zymodemes.

The pathogenic potential of four Entamoeba histolytica isolates obtained from asymptomatic carriers and possessing nonpathogenic zymodemes was compared to four E. histolytica strains obtained from invasive cases of amebiasis and having pathogenic zymodemes. Both xenic and axenic cultures of a number of strains were tested. Determinations of cytopathogenicity were done in vitro by measuring the rates of destruction of tissue cultured monolayers of baby hamster kidney cells by intact amebae or by its cell-free extracts. The in vivo virulence was tested by assessing their capacity to form hepatic abscesses in hamsters or cecal ulcerations in rats. The results obtained show that two of the isolates from asymptomatic carriers (strains SAW 1734R clAR and WI:0385:191) were as virulent as three of the invasive ones (HM-1:IMSS, 200:NIH, and SAW 408). Two other isolates from asymptomatic carriers and one from a dysentery case were avirulent. All the E. histolytica isolates tested were similarly sensitive to metronidazole and emetine (IC50 1-10 micrograms/ml). The results indicate that the pathogenic potential of E. histolytica varies between isolates and can be affected by culture conditions and by the presence or absence of bacterial cells. These findings suggest that virulence does not necessarily correlate with a pathogenic zymodeme.

Amebiasis↗
PubMed2026

Global prevalence of hereditary hemorrhagic telangiectasia-associated variants estimated by analysis of large-scale genomic databases.

BACKGROUND: Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder with an overwhelming hemorrhagic phenotype. It is mainly caused by variants in the ENG and ACVRL1 genes. HHT prevalence is currently estimated to be 1 in 5000 individuals, but the disease is likely underdiagnosed due to variable clinical presentation, misdiagnosis, and delayed recognition. OBJECTIVES: To estimate the global genetic prevalence of HHT-associated variants in ENG and ACVRL1. METHODS: We analyzed 3 large population-scale genomic databases: gnomAD, All of Us, and Regeneron Genetics Center-Million Exome. We considered known pathogenic and likely pathogenic variants of ENG and ACVRL1 and extended the analysis to potentially pathogenic variants passing the pathogenic criteria established by the guidelines for HHT of the American College of Medical Genetics and Genomics/Association for Molecular Pathology. RESULTS: The genetic prevalence of HHT ranged from 1.753 to 2.555 in 5000 individuals, when considering only pathogenic and likely pathogenic variants, and from 2.874 to 4.327 in 5000 individuals, when also potentially pathogenic variants were considered. CONCLUSION: This study assesses the prevalence of HHT-associated variants in the general population. Our unbiased approach demonstrates that the genetic prevalence of the disease is substantially higher than currently estimated.

Humans↗
PubMed1978

Bacteriology of expectorated sputum with quantitative culture and wash technique compared to transtracheal aspirates.

Techniques to improve the reliability of expectorated sputum culture were evaluated in 46 patients using a wash technique, quantitative culture, and a combination of washing and quantification. The wash procedure consisted of a jet of tap water over the specimen contained in a tea strainer. The true lower respiratory tract flora was determined by percutaneous transtracheal aspirates, which served as the basis for evaluating the methods of processing expectorated specimens. Either washing alone or quantification alone decreased the number of specimens with organisms that were not present in companion transtracheal aspirates; however, results that were sufficiently improved to be clearly advantageous for clinical interpretation were achieved only when washing and quantification were combined. Washed sputum specimens yielded oropharyngeal "contaminants" in concentrations exceeding 10(6) bacteria per ml in 12 of 46 specimens (26 per cent). Using this technique, only one specimen contained a misleading potential pathogen, and only one specimen failed to yield a potential pathogen that was recovered with the transtracheal aspirate. The wash procedure decreased the mean concentrations of contaminants approximately 100-fold for all specimens and 1,000-fold for purulent specimens.

Anaerobiosis↗
PubMed1979

Bacteriological quality control in human milk-banking.

The bacteriological quality of pooled human milk donated to the Oxford milk bank was analysed and the effects on bacteriology of sterilisation of the milk-collecting vessels in the home with hypochlorite solution and of Holder pasteurisation in a purpose-built human-milk pasteuriser were studied. Collecting milk in hypochlorite-sterilised vessels resulted in a significantly lower bacterial count of both pathogens and species of unlikely pathogenicity before pasteurisation and significantly increased the chance of pasteurisation giving a sterile product. Potentially pathogenic organisms grown in untreated milk were Escherichia coli, Staphylococcus aureus, and group B beta-haemolytic streptococci. Seven species of organisms of unlikely pathogenicity were also identified. Pasteurisation eliminated all potential pathogens from milk but did not reliably remove any of the species of unlikely pathogens. Banked human milk may be contaminated with bacteria which are known to be capable of producing lipases, proteases, and decarboxylases. Accurate pasteurisation, together with attention to the sterility of the collecting vessels, results in a bacteriologically safe product that retains many of the protective properties of raw milk.

Disinfection↗
PubMed1984

Evaluation of a two-hour method for screening pathogens from stool specimens.

The 2-h stool-screening test (SST) (API System S.A., Montalieu-Vercieu, France) was used to screen 231 organisms yielding suspicious colonies on stool differential agars for potential pathogens. All 54 salmonellae yielded correct screens. Of 14 shigellas, 9 keyed as possible Shigella spp.-Yersinia enterocolitica-rare Salmonella spp. (SYS), and 5 (all Shigella sonnei) keyed as possible S. sonnei-Y. enterocolitica-Arizona spp. (SYA). Three Arizona strains were identified as probable Salmonella spp., two were identified as SYA, and one was identified as SYS. Seven Y. enterocolitica strains keyed as SYS, and two keyed as SYA; one strain was screened out as a nonpathogen. The two Aeromonas hydrophila strains keyed as SYA, and the two Plesiomonas shigelloides strains keyed as SYS. All 63 Proteus, Morganella, Providencia, and Pseudomonas aeruginosa strains were screened out as nonpathogens. Among 80 coliforms, 37 were screened as SYA, 32 were screened as SYS, and 11 were screened as nonpathogens. On the basis of the SST, 69/80 coliforms would have been tested further. However, only 1/88 potential pathogens would have been missed, and all Proteus, Morganella, Providencia, and P. aeruginosa strains would have been excluded. The capability of the SST (when combined with a rapid identification method) of providing same-day identification of potential stool pathogens must be weighed against its inability to effectively screen out coliforms. The cost of this method is equivalent to that of a three-tube conventional screening method. The suitability of the SST for individual laboratories must be predicated on the incidence of stool pathogens and commensals in the specific setting as well as on factors related to work flow, technologist acceptability, and turnaround time.

Aeromonas↗
PubMedDate not supplied

[Quantitative bacteriology of sputum collected by a simple technic limiting salivary contamination].

A simple non-invasive method to improve the reliability of bacteriological analyses of sputum was evaluated in 25 patients with chronic bronchitis. This method consists of placing dental cotton swabs between the cheek and the gum and under the tongue at the level of the excretory salivary glands. Once these plugs are in place, the sputum is collected by coughing under the control of a physiotherapist. The quantitative bacteriological data from sputum collected by the "protected" and "unprotected" methods were compared with those from bronchial secretions collected by transtracheal aspiration, used as reference method. Oropharyngeal cells and commensal bacteria were isolated at a significantly lower frequency in sputum collected by the protected method. Considering the predominant pathogenic bacteria, an excellent correlation was obtained between transtracheal aspiration and sputum in 80% of cases when sputum was collected by protected method and in 68% of cases by unprotected method. In four patients, the transtracheal aspiration was sterile, while a potentially pathogenic organism associated with a high leukocyte numeration was identified in sputum. All the potential pathogens isolated in the positive transtracheal aspiration were recovered in the protected sputum (100%), but they could be associated with a non-predominant commensal flora (11 cases) or a potentially misleading pathogenic bacteria (2 cases).

Adult↗
PubMed2006

Positive correlation between in vivo and in vitro assays for the evaluation of Pseudomonas virulence.

Some bacterial phenotypes measured in vitro can be used to access bacterial virulence, on the premise that they are positively correlated with data from in vivo experiments. We show here that in vitro assessment of bacterial phenotypes, such as adherence and cytotoxicity, are positively correlated with data from in vivo experiments in Drosophila and can be used to assess bacterial virulence in vivo. Manipulation of environmental parameters, such as iron availability, induced changes in the phenotypes measured in vitro that correlated with changes in vivo virulence of all strains tested. Applying these assays, we demonstrate the pathogenic potential of a Pseudomonas fluorescens strain, initially isolated as a non-pathogenic milk contaminant. This strain displayed adherence and cytotoxicity comparable to those of the Pseudomonas aeruginosa pathogenic strain PAK, and colonized the infected flies as rapidly as the PAK strain. These results indicate that this "a priori" non-pathogenic bacterium is capable of escaping the host immune response, supporting the use of in vitro tests for screening of potential pathogens.

Animals↗
PubMedDate not supplied

Biohazards of investigations on the transmissible spongiform encephalopathies.

There is considerable current interest in the agents that cause the spongiform encephalopathies: scrapie, transmissible mink encephalopathy, kuru, and Creutzfeldt-Jakob disease (CJD). The unusual properties of these agents, their elusiveness, and their pathogenicity for humans (in the cases of kuru and CJD) make these agents interesting subjects of investigation but also make imperative a consideration of their potential biohazards in the laboratory. In view of both the potential pathogenicity of these agents and the potential hazards of many laboratory procedures, a series of physical containment levels, each of which corresponds to a range of composite risk factors, are suggested. The estimated composite risk factor used is a function of the potential pathogenicity or relative risk factor of the agent and the potential hazard of a laboratory procedure. The lowest risk factors (1 to 2+) correspond to levels of containment similar to those recommended by the Center for Disease Control for class II microorganisms, while the highest risk factors (5 to 8+) correspond to levels similar to those for class III microorganisms. The use of such a biohazard ranking system aids in a rational approach to selection of equipment and procedures.

Animals↗
PubMed1997

The microbial ecology and immunology of the adenoid: implications for otitis media.

The nasopharyngeal tonsil, or adenoid, is a major inductive site for the synthesis of J-chain-positive B cells that may migrate to other areas of the upper respiratory tract, such as the nasal mucosa, the parotid gland, the lacrimal gland, and the middle ear during inflammation. The production of secretory IgA by both the nasopharyngeal tonsil and the nasal mucosa plays a major role in local immune protection against bacteria and viruses. The release of cytokines from Th1 and Th2 lymphocytes must be appropriate for B cells to produce IgA. The factors or mechanisms responsible for this are not, at present, known, but it appears that there is a difference in the profiles of cytokine secretion by Th1 and Th2 lymphocytes in the adenoids in both otitis-prone, as well as nonotitis-prone children. We have suggested that if this specific immune system does not protect the host from invasion by potential pathogens, there are other modalities of therapy to protect the nasopharynx from colonization with pathogenic bacteria or viruses. These include the production of specific antibodies against bacterial surface proteins that have been identified as mucin-binding proteins. Alteration of the microbial flora with commensal organisms such as viridans streptococci can be utilized. These alpha-hemolytic streptococci probably function by producing an acid environment that prevents colonization of organisms such as nontypeable H. influenzae. Finally, the induction of specific SIgA by conserved outer membrane protein antigens of potential pathogens may be another strategy in the prevention of colonization of potential bacterial pathogens in the nasopharynx.

Adenoids↗
PubMed1983

Hemolytic Escherichia coli strains in the human fecal flora as potential urinary pathogens.

Hemolysin production is presumed to be a virulence factor in extraintestinal, e.g. urinary tract, infections caused by Escherichia coli. In order to investigate its incidence among the fecal flora, particularly in combination with other presumptive virulence factors, 369 and 373 fecal isolates from Würzburg, FRG and Lima, Peru respectively were examined. 12% of the former and 4% of the latter were hemolytic (Hly+) compared to 33% of 249 E. coli strains isolated from urinary tract infections in Würzburg. In comparison to those which were non hemolytic (Hly-), Hly+ fecal E. coli isolates were associated to a far greater extent with other factors implicated in urinary tract virulence. 41% of these Hly+ strains (cf. 8% Hly-) possessed mannose resistant hemagglutination (MRHA types V, VI, VII). In addition they belonged to the "common O serogroups" O1, O2, O4, O6, O7, O8, O18, O25, O75 in 61% of cases (cf. 25% Hly-) and they possessed K5 antigen in 13% of instances (cf. 2.5% Hly-). The occurrence of these three virulence factors among Hly+ fecal E. coli strains is very similar to that observed among E. coli urinary isolates. One may conclude that these Hly+ fecal strains constitute a "pool" of potential urinary tract pathogens.

Adult↗
PubMedDate not supplied

[Moraxella (Branhamella) catarrhalis. A common pathogenic agent].

Moraxella (Branhamella) catarrhalis, a commensal organism of the oropharyngeal flora, has been considered a potential pathogen since the early 1970s, mainly causing otitis in infants and exacerbations of chronic bronchitis in the elderly or in immunosuppressed adults. This view was initially based on the isolation of M. catarrhalis during infections: a density of at least 10(7)/ml of sputum, particularly when it exceeds that of other organisms by at least 100-fold, is considered to indicate the responsibility of M. catarrhalis. The pathogenic potential of M. catarrhalis was proven by the increase in specific serum antibodies (total, IgG, IgA) in patients infected by this organism. Given the large proportion (60 percent) of strains that produce beta-lactamase, antibiotic therapy is based on a combination of amoxycillin and clavulanic acid (or another penicillin/beta-lactamase inhibitor combination) or a third-generation cephalosporin; tetracyclines or macrolides can also be used.

Anti-Bacterial Agents↗
PubMed1999

BALB/c mice produce blister-causing antibodies upon immunization with a recombinant human desmoglein 3.

Pemphigus vulgaris (PV) is an Ab-mediated autoimmune blistering disease of mucotaneous surfaces. Over 95% of the patients with PV express DR4 or DRw6, and the disease is characterized by the presence of autoantibodies directed against desmoglein 3 (Dsg 3), a protein expressed on keratinocytes. An appropriate animal model is required to understand immunoregulation and to address the role of immunogenetic components in the production of pathogenic Abs that are characteristic of PV. Therefore, we turned to the development of a mouse model. Four strains of female mice (BALB/c, DBA/1, SJL/J, and HRS/J) were screened for their ability to produce pathogenic anti-Dsg 3 Abs. We demonstrated that only BALB/c mice immunized with a full-length Dsg 3 can produce pathogenic Abs capable of causing acantholysis of human foreskin in culture and blistering in neonatal mice. This observation suggested that either H-2d or the BALB background contains the immunogenetic makeup necessary for the production of pathogenic anti-Dsg 3 Abs. No correlation was noted between a given isotype and the pathogenic potential of autoantibodies from different strains of mice. Similarly, the pattern of reactivity of Abs with a panel of 46 synthetic peptides that span the entire Dsg 3 failed to reveal any association between binding specificity and the pathogenic potential, and suggested that pathogenic Abs might recognize conformational epitopes. Moreover, our studies showed that the epitopes recognized by pathogenic Abs are contained within the extracellular Dsg 3.

Animals↗
PubMed2006

Blood pressure cuff as a potential vector of pathogenic microorganisms: a prospective study in a teaching hospital.

OBJECTIVE: To investigate the potential role of blood pressure (BP) cuffs in the spread of bacterial infections in hospitals. DESIGN: A comprehensive, prospective study quantitatively and qualitatively evaluating the bacterial contamination on BP cuffs of 203 sphygmomanometers in use in 18 hospital units from January through March 2003. SETTING: A university hospital with surgical, medical, and pediatric units. RESULTS: A level of contamination reaching 100 or more colony-forming units per 25 cm(2) was observed on 92 (45%) of inner sides and 46 (23%) of outer sides of 203 cuffs. The highest rates of contamination occurred on the inner side of BP cuffs kept in intensive care units (ICUs) (20 [83%] of 24) or on nurses' trolleys (27 [77%] of 35). None of the 18 BP cuffs presumed to be clean (ie, those that had not been used since the last decontamination procedure) had a high level of contamination. Potentially pathogenic microorganisms were isolated from 27 (13%) of the 203 BP cuffs: 20 of these microorganisms were Staphylococcus aureus, including 9 methicillin-resistant strains. The highest rates of contamination with potentially pathogenic microorganisms were observed on cuffs used in ICUs and those kept on nurses' trolleys. For 4 patients with a personal sphygmomanometer, a genetic link was found between the strains isolated from the BP cuffs and the strains isolated from the patients. CONCLUSIONS: The results of this survey highlight the importance of recognizing BP cuffs as potential vectors of pathogenic bacteria among patients and as a source of reinfection when dedicated to a single patient, emphasizing the urgent need for validated procedures for their use and maintenance.

Bacteria↗
PubMedDate not supplied

Virulence of pathogenic and non-pathogenic zymodemes of Entamoeba histolytica (Indian strains) in guinea-pigs.

Guinea-pigs were inoculated with Entamoeba histolytica strains isolated from cases of amoebic liver abscess, amoebic dysentery and asymptomatic cyst passers and the strains were classified in zymodemes by isoenzyme electrophoresis. It was observed that certain non-pathogenic zymodemes were potentially pathogenic for the guinea-pigs. The relationship of zymodemes and virulence in laboratory animals is discussed.

Amebiasis↗
PubMed2024

Filamentous bacteria-induced sludge bulking can alter antibiotic resistance gene profiles and increase potential risks in wastewater treatment systems.

Sludge bulking caused by filamentous bacteria is a prevalent issue in wastewater treatment systems. While previous studies have primarily concentrated on controlling sludge bulking, the biological risks associated with it have been overlooked. This study demonstrates that excessive growth of filamentous bacteria during sludge bulking can significantly increase the abundance of antibiotic resistance genes (ARGs) in activated sludge. Through metagenomic analysis, we identified specific ARGs carried by filamentous bacteria, such as Sphaerotilus and Thiothrix, which are responsible for bulking. Additionally, by examining over 1,000 filamentous bacterial genomes, we discovered a diverse array of ARGs across different filamentous bacteria derived from wastewater treatment systems. Our findings indicate that 74.84% of the filamentous bacteria harbor at least one ARG, with the occurrence frequency of ARGs in these bacteria being approximately 1.5 times higher than that in the overall bacterial population in activated sludge. Furthermore, genomic and metagenomic analyses have shown that the ARGs in filamentous bacteria are closely linked to mobile genetic elements and are frequently found in potentially pathogenic bacteria, highlighting potential risks posed by these filamentous bacteria. These insights enhance our understanding of ARGs in activated sludge and underscore the importance of risk management in wastewater treatment systems.

Sewage↗
PubMed1993

Microbiologic and clinical aspects of a trial of once daily cefixime compared with twice daily cefaclor for treatment of acute otitis media in infants and children.

In this randomized, investigator-blinded multicenter study, tympanocentesis for acute otitis media with effusion in 137 ears from 108 children, 6 months to 12 years of age, revealed 84 definite pathogens and 32 potential pathogens. Twenty-nine aspirates from 23 subjects were sterile. Of the 116 isolates 42 (36%) were Streptococcus pneumoniae, 24 (21%) were Haemophilus influenzae, 9 (8%) were Moraxella catarrhalis, 9 (8%) were Streptococcus pyogenes and 1 (1%) was Staphylococcus aureus. Twenty-two (19%) definite pathogens produced beta-lactamase. Patients were randomized to cefixime (8 mg/kg/day daily) or cefaclor (40 mg/kg/day divided into two doses). Efficacy was determined by pneumatic otoscopy and tympanometry at the end of therapy visit on Days 11 to 14 and up to 4 weeks of follow-up. At end of therapy subjects with definite pathogens exhibited a satisfactory clinical outcome in 26 of 36 (72%) ears for cefaclor and 40 of 48 (83%) ears for cefixime recipients (P = 0.12). For ears with beta-lactamase-producing isolates there were no (0 to 12) cefixime failures but 4 of 10 cefaclor failures (P = 0.03). Diarrhea/loose stools were more frequent in cefixime (16 of 58) than cefaclor (4 of 50) recipients. One cefixime subject required discontinuation of drug. Overall efficacy for treatment of acute otitis media with effusion was not different; however, cefixime appeared more effective for infections caused by beta-lactamase-producing organisms.

Acute Disease↗
PubMed1996

Immune response to Fusobacterium nucleatum and Prevotella intermedia in patients with infectious mononucleosis.

The role of four oral flora organisms (Fusobacterium nucleatum, Prevotella intermedia, Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans) was investigated in 22 patients with infectious mononucleosis. Immunoglobulin-G class antibody titres to these organisms were measured by enzyme-linked immunosorbent assay. Serum levels in the patients were determined at day 1 and 42-56 days later. Significantly higher antibody levels to F. nucleatum and Pr. intermedia were found in the second serum sample of patients as compared to their first sample. The elevated antibody levels to F. nucleatum and Pr. intermedia, known oral pathogens, suggest a potential pathogenic role for these organisms in the pharyngo-tonsillitis associated with infectious mononucleosis.

Adolescent↗