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PubMed1999

Necrotising enterocolitis: is there a relationship to specific pathogens?

UNLABELLED: Outbreaks of necrotising enterocolitis (NEC) have often been related to specific pathogens such as Enterobacteriaceae. This relationship, however, remains uncertain because of the retrospective nature of the studies addressing this issue. We performed a prospective study to investigate whether there is indeed an association between NEC and specific pathogens. Between April 1993 and March 1997, stools of neonates of < 36 weeks admitted to our neonatal unit were investigated for bacteria in weekly intervals. Clinical and bacteriological data from each infant who developed NEC were compared with those from two control infants matched for gestational age and date of admission. Eighteen infants developed 19 episodes of NEC (clinical signs + air in portal vein); 8 of these had laparotomy; two died. Occurrences of NEC were homogeneously distributed over the 4-year study period. The only significant differences in the clinical course prior to NEC were a more severe stage of respiratory distress syndrome [median 2 (0-4) vs. 0 (0-3), P < 0.05] and a higher proportion of infants who had only been formula fed (63 vs. 32%, P < 0.05) in the cases. Within the last week prior to NEC, potentially pathogenic bacteria were identified in stools of all cases and 79% of controls (P < 0.05). However, there was no significant difference in the occurrence of specific pathogens or groups of pathogens in cases compared with controls. CONCLUSION: Although gut colonisation with potential pathogens appeared to be a prerequisite for the development of NEC, there were no specific bacteria associated with this disease if data from infants with NEC were compared with those from time- and gestational age-matched controls.

Case-Control Studies↗
PubMedDate not supplied

Cattle pathogen tritrichomonas foetus (Riedmüller, 1928) and pig commensal Tritrichomonas suis (Gruby & Delafond, 1843) belong to the same species.

A number of reports suggest that the sexually transmitted pathogen of cattle, Tritrichomonasfoetus, and a gastrointestinal commensal of pigs, Tritrichomonas suis, are very similar and may be co-specific. A conclusive review of the taxonomic and nomenclatural status of these species has not been presented so far. Toward this end, we reexamined and compared porcine and bovine trichomonads with regard to their morphology, pathogenic potential, and DNA polymorphism. Using light and electron microscopy, no distinguishing features between T. foetus and T. suis strains were found in size, general morphology, and karyomastigont structure. Both bovine and porcine trichomonads showed pathogenic potential in the subcutaneous mouse assays and did not separate into distinct groups according to strain virulence. Three DNA fingerprinting methods (i.e. RFLP, RAPD, and PCR-based analysis of variable-length DNA repeats) that produce species-specific DNA fragment patterns did not distinguish between the bovine and porcine strains. Sequencing of a variable 502-bp DNA fragment as well as comparison of 16S rRNA gene sequences did not reveal species-specific differences between the cattle and porcine strains. Therefore, we conclude that T. foetus and T. suis belong to the same species. To prevent confusion that may arise from T. foetus-T. suis synonymy, we propose to suppress the older name suis and maintain its accustomed junior synonym foetus as a nomen protectum for both cattle and porcine trichomonads. The case has been submitted to the International Commission on Zoological Nomenclature for ruling under its plenary power.

Animals↗
PubMed1995

Bacterial colonization of the larynx and trachea in healthy children.

Fifty healthy children were included in the study; tracheal and laryngeal aspirations were performed after oral endotracheal intubation during minor surgery. The aspirates were evaluated and examined in the same way as aspirates from children suspected of pneumonia; 31 samples were accepted for the final analysis. After culturing, specimens from 30 children exhibited growth of potential pathogenic bacteria either from the larynx, the trachea or both. Prior to culture, bacteria were seen by microscopy in 24 samples from 30 children. These results indicate that the majority of healthy children carry potential pathogenic bacteria, not only in the larynx but also to a certain extent in the trachea. We conclude that aspirates from the larynx and the trachea are of limited value in the diagnosis of bacterial pneumonia in children.

Adolescent↗
PubMed1996

Evaluation of polymerase chain reaction-restriction enzyme analysis of mycobacteria cultured in BACTEC 12B bottles.

Polymerase chain reaction with restriction enzyme analysis (PRA) was first tested on 15 reference strains and 50 subcultured clinical isolates of mycobacteria according to the reference algorithm by Telenti et al [1]. Next, we evaluated the application of this method to 108 isolates from liquid media (BACTEC 12B). Of them, 15 M. tuberculosis complex and 81 mycobacteria other than tuberculosis (MOTT) had comparable results with both PRA and the BACTEC 460 TB systems. However, seven M. tuberculosis complex and three potentially pathogenic MOTT were identified by PRA rather than the BACTEC TB system. PRA seems to be an efficient method for the identification of mycobacteria to the species level and a good aid to detect potentially pathogenic mycobacteria, especially in mixed mycobacterial cultures.

Humans↗
PubMed2004

[Bacterial colonization and home mechanical ventilation: prevalence and risk factors].

OBJECTIVE: To investigate the prevalence of bacterial contamination of ventilators and colonization of patients, the bacteria implicated, and predisposing factors in noninvasive home ventilation. MATERIAL AND METHODS: Forty patients on a home noninvasive ventilation program (mean [SD] age: 63.1 [12] years; time on ventilation: 30.7 [25] months; daily use: 8.1 [2] hours) were enrolled in this descriptive cross-sectional study. Microbiological samples for semiquantitative cultures were swabbed from the ventilator (mask and tubing) and the nostrils. A questionnaire was completed on the underlying disease, time on the ventilation program, type of ventilator, presence of a humidifier, and attention to ventilator cleanliness and maintenance. We defined "colonization" as the presence of microorganisms in the nostrils without evidence of a host immune response, and "contamination" as the presence of surface microorganisms (on tubing or the nasal mask). RESULTS: Potentially pathogenic bacteria were isolated from 6 ventilators (15%) and the nasal swabs of 10 patients (25%). Staphylococcus aureus was the most frequently isolated one (in 5 ventilators and 6 patients--contamination coinciding with colonization in 3 cases). Other potentially pathogenic bacteria isolated were Proteus species (from the nostrils of 2 patients) and an unidentified gram-negative bacillus from the ventilator. On analysis by underlying disease, 60% of the patients with obesity had been colonized. No other findings of note were obtained for other diseases. Contamination and colonization correlated with attention to cleanliness and maintenance of the ventilator but not with type of ventilator, time on the ventilation program, or use of a humidifier. CONCLUSIONS: Home mechanical ventilators are a potential source of nasal colonization. The most frequently encountered microorganism was S. aureus. The degree of ventilator cleaning and disinfection seems to affect contamination; thus it is necessary to impress on patients the need for adequate maintenance of their ventilators.

Adult↗
PubMed1999

Fully automated liquid culture system compared with Löwenstein-Jensen solid medium for rapid recovery of mycobacteria from clinical samples.

The aim of this study was to compare the rate of recovery of mycobacteria and the time to detection in 5208 samples using the MB/BacT culture system (Organon Teknika, USA) and Löwenstein-Jensen medium. Mycobacteria were recovered from 301 (5.7%) samples. Two hundred fifty-seven (85.3%) isolates from 114 patients were Mycobacterium tuberculosis [135 (52.5%) smear-positive, 122 (47.4%) smear-negative], and 44 (14.6%) were potentially pathogenic environmental mycobacteria. The yield with the MB/BacT was higher than that with Löwenstein-Jensen [287 (95.3%) vs. 200 (66.4%), P<0.001] for both Mycobacterium tuberculosis [247 (96.1%) vs. 187 (72.7%), P<0.001] and potentially pathogenic environmental mycobacteria [40 (90.9%) vs. 13 (29.5%), P<0.001], mainly at the expense of the smear-negative samples. Moreover, 70 (27.2%) samples were positive only in the MB/BacT, whereas ten (3.8%) samples were positive only in Löwenstein-Jensen. The number of patients with tuberculosis detected by the MB/BacT was higher than that detected by Löwenstein-Jensen medium [111 (97.3%) vs. 89 (78%), P<0.001]. In 25 (21.9%) patients the diagnosis was established solely by means of the MB/BacT. In smear-positive and smear-negative samples, the mean times to detection of Mycobacterium tuberculosis were 16.7 and 26.3 days, respectively, with Löwenstein-Jensen and 11.5 and 19.3 days, respectively, with the MB/BacT. These results indicate that the MB/BacT is more efficient and faster than Löwenstein-Jensen for the recovery of mycobacteria.

Bacteriological Techniques↗
PubMed1979

The microbial flora in extended-wear soft contact-lens wearers.

Of 857 cultures of material collected from the eyelids, conjunctivae, and contact lenses of 51 extended-wear soft-contact-lens wearers, 44 (5%) grew potential pathogens. The aphakic patients wearing contact lenses had fewer recoverable pathogens (24 of 295 or 8%) than a group of preoperative cataract patients (63 of 295 or 21%). On five occasions, positive cultures accompanied clinical symptoms, and on three occasions, repeated cultures grew the same potential pathogen.

Aphakia, Postcataract↗
PubMed1983

[Microorganisms in home-care inhalation devices].

Contamination of inhalation equipment used at home, cleaning procedures, and the occurrence of potentially pathogenic micro-organisms in mouthwash water was studied in 55 patients. Fungi in the oropharyngeal space were found in 58%, Staphylococcus aureus in 29%, Enterobacteriaceae in 47% and Pseudomonas aeruginosa in 11%. Contamination with potentially pathogenic micro-organisms occurred in 64% of inhalation equipment and inhalation solutions. In a total of 151 samples from the equipment Klebsiella was present in 14%, Enterobacter in 10%, Serratia and Acinetobacter in 11% each, Pseudomonas in 5% and Staphylococcus aureus in 4.5%. In three cases the same serotype of Ps. aeruginosa was present in the oropharyngeal cavity and inhalation equipment. In most cases the cleansing of the inhalation equipment had been inadequate. Only 36% of those questioned cleaned the equipment immediately before use, only 4 of 20 stated that they washed their hands before use. Subjective assessment of the value of inhalation treatment was either "very good" or "good" in 80%.

Aerosols↗
PubMed1988

Effects of antimicrobial therapy on sperm-mucus interaction.

Sperm-mucus interaction under in-vitro or in-vivo conditions might be affected by microorganisms colonizing the reproductive tract. In order to study the influence of antimicrobial therapy, an extensive microbial screening was performed including Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, a broad spectrum of potentially pathogenic aerobic and anaerobic bacteria, Trichomonas vaginalis, herpes simplex virus and yeasts. One-hundred-and-six couples with a mean duration of infertility of 5.5 years (range 1-12 years) and with isolation of potentially pathogenic microorganisms in semen samples and/or cervical swabs were submitted to a prospective pilot study. None of the patients displayed signs or symptoms of infection in the lower genital tract. Before and after specific therapy, based on antimicrobial susceptibility testing, sperm analyses and in-vitro sperm penetration meter tests (SPMT) (Kremer) were performed. SPMT was evaluated with cervical mucus of patients' wives, collected after a standardized oral treatment with oestrogens and, additionally, in a crossed manner with cervical mucus and spermatozoa of fertile donors. The success of antimicrobial therapy was controlled by repeating the same microbial screening and was 96%. However, there was a marked change in the microbial pattern. A comparison of the results of sperm analyses before and after treatment revealed neither significant differences for sperm volume, sperm count, propulsive motility, morphology, vitality, pH, fructose concentration or number of round cells, nor was there a significant influence on the cervical index and the number of leukocytes in cervical mucus.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Qualitative and quantitative researches into bacterial flora of respiratory apparatus (author's transl)].

The first group of data illustrated in this research concern the isolation's frequencies of bacterial strains from 7000 samples of respiratory materials examinated in two years, 1973 and 1974, by two different techniques. Significant differences were observed in the isolation's percentage of various bacterial strains; these differences, at least partly, can be attributed at the different techniques employed in two years. The second group of data is represented by results of bacterial quantitation performed in 100 samples of purulent sputum, with respectives clinical notes unknown. Potentially pathogenous strains in pure culture and at a concentration of 10(7) or higher were isolated only in 16 samples of sputum in the other samples normal bacterial flora was isolated alone or associated with potentially pathogenous strains.

Candida albicans↗
PubMed2004

Listeria monocytogenes: comparative interpretation of mouse virulence assay.

Being an opportunistic bacterial pathogen, Listeria monocytogenes demonstrates significant strain variations in virulence and pathogenicity. The availability of laboratory procedures to ascertain the pathogenic potential of L. monocytogenes bacteria would greatly enhance the control and prevention of listerial infections. As a method that measures all virulent determinants, mouse virulence assay has been frequently used for assessing L. monocytogenes virulence. The pathogenic potential of a given L. monocytogenes strain as determined by mouse virulence assay is often calculated from mouse mortality data in combination with colony forming units (CFUs) derived from plate counts, and expressed by medium lethal dose (LD(50)). In this report, we describe an alternative method [i.e., relative virulence (%)] that does not involve CFU estimation, and is comparable to LD(50) for interpretation of mouse virulence assay for L. monocytogenes. The relative virulence (%) is obtained by dividing the number of dead mice with the total number of mice tested for a particular strain using a known virulent strain (e.g., L. monocytogenes EGD) as reference. Besides providing a more direct interpretation in comparison with LD(50) values for mouse virulence assay, this method requires fewer dosage groups per L. monocytogenes strain, and eliminates CFU estimation that is step subject to variations between runs and also between laboratories.

Animals↗
PubMed1997

Teicoplanin in cardiac surgery: intraoperative pharmacokinetics and concentrations in cardiac and mediastinal tissues.

The concentrations of teicoplanin in the sera and mediastinal and heart tissues of 23 patients undergoing cardiac surgery were measured after two regimens of teicoplanin administration. Intraoperative pharmacokinetic parameters were also obtained. Patients were randomized into two groups. Those in group 1 were given teicoplanin at 6 mg x kg(-1) intravenously at the time of induction of anesthesia. Patients in group 2 were given teicoplanin at 12 mg x kg(-1) during the same period. The maximum concentration in serum (71 +/- 20 and 131 +/- 44 mg x l(-1)), the minimum concentration in serum (3.6 +/- 1.3 and 6.8 +/- 2.1 mg x l(-1)), the area under the concentration-time curve (AUC) from 0 to 12 h (108 +/- 20 and 217 +/- 38 microg x h x ml(-1)), and the AUC from 0 h to infinity (154 +/- 36 and 292 +/- 77 microg x h x ml(-1)) were twice as high after 12-mg x kg(-1) injections as after 6-mg x kg(-1) injections. No differences in mean residence time (9.7 +/- 4.9 and 8.4 +/- 2.7 h) or terminal half-life (8.5 +/- 3.8 and 7.5 +/- 2.3 h) were observed. Teicoplanin penetrated mediastinal and heart tissues but not sternal bone, where the antibiotic was detectable in only 1 of 13 patients in group 1 and 2 of 10 patients in group 2. In group 1, 7 of 13 patients had teicoplanin concentrations in tissue that were lower than the MIC for 90% of the strains of potential pathogens tested (MIC90) that cause infection after cardiac surgery. All of the patients in group 2 but one had teicoplanin concentrations in tissue (other than in sternal bone) far in excess of the MIC90 for the potential pathogens. In conclusion, the 12-mg x kg(-1) regimen of teicoplanin is followed by a significant increase in teicoplanin concentrations in heart and mediastinal tissues and should be preferred to the 6-mg x kg(-1) regimen if teicoplanin is selected for antimicrobial prophylaxis in open heart surgery.

Adult↗
PubMed2006

Acanthamoeba isolates belonging to T1, T2, T3, T4 and T7 genotypes from environmental freshwater samples in the Nile Delta region, Egypt.

The free-living amoebae of the genus Acanthamoeba include non-pathogenic and pathogenic species and has been recently classified into 15 different genotypes, T1-T15. In this study, a survey was conducted in order to determine the presence and pathogenic potential of free-living amoebae of Acanthamoeba genus in freshwater sources associated with human activities in the Nile Delta region, Egypt. Identification of Acanthamoeba was based on the morphology of cyst and trophozoite forms and PCR amplification with a genus specific primer pair. The pathogenic potential of Acanthamoeba isolates was characterized using temperature and osmotolerance assays and PCR reactions with two primer pairs specific to Acanthamoeba pathogenesis. Isolates genotypes were also determined after ribosomal DNA sequencing. These data revealed that isolates belong to T1, T2, T3, T4 and T7 genotypes. As expected, T4 isolates exhibited the most pathogenic traits and were osmotolerant, temperature tolerant and expressed extracellular serine proteases. This is the first report presenting environmental distribution of Acanthamoeba genotypes in Egypt.

Acanthamoeba↗
PubMed1992

Potential for local and systemic bacterial infection in some occupational groups in Benin City, Nigeria.

BACKGROUND: Many Third World countries may not have adequate facilities for rapid sensitivity testing of antibiotics as an aid to diagnosis and chemotherapy. It may therefore be valuable to relate bacterial carriage on the skin to type of work a person does. METHODS: Given areas of skin in workers from 10 occupational groups were sampled. The bacteria obtained were analyzed after growth on appropriate media. The sensitivity profiles of potential pathogens isolated from these groups, as well as of those (Staphylococcus aureus only) isolated from patients with certified infections, were carried out and the results were analyzed. RESULTS: Staphylococcus aureus constituted the most widely and frequently isolated potential pathogen. Proteus mirabilis, Escherichia coli, and Klebsiella species were also frequent colonizers of skin. There was a statistical relationship between work type and overall prevalence of bacteria on skin (p less than 0.01). Most isolates of the work groups were highly sensitive to gentamicin and cefuroxine but not to penicillin G, ampicillin, and trimethoprim plus sulfamethoxazole; isolates from infected persons were generally more resistant than were the community-acquired ones. CONCLUSIONS: A relationship may exist between the types of bacteria carried on the skin and the type of work in which a person is engaged.

Bacteria↗
PubMed2000

Evaluation of antimicrobial treatment in mechanically ventilated patients with severe chronic obstructive pulmonary disease exacerbations.

OBJECTIVE: To study microbial and susceptibility patterns and antimicrobial treatment responses in patients with severe, acute exacerbations of chronic obstructive pulmonary disease requiring mechanical ventilation. DESIGN: Microbial investigation using tracheobronchial aspirates, bronchoscopy with a protected specimen brush, and bronchoalveolar lavage, as well as paired serologies. Evaluation of antimicrobial treatment by results of the initial investigation, susceptibility testing, and a repeated microbial investigation (tracheobronchial aspirates, bronchoscopy with a protected specimen brush, and bronchoalveolar lavage) after 72 hrs. SETTING: A respiratory intensive care unit of a 1,000-bed teaching hospital. PATIENTS: Fifty severely exacerbated and mechanically ventilated patients with chronic obstructive pulmonary disease. INTERVENTIONS: Initial empirical antimicrobial treatment according to clinical judgment. MEASUREMENTS AND MAIN RESULTS: Overall, 36 of 50 patients (72%) had evidence of a microbial origin. Community-acquired endogenous pathogens were present in 70% of patients, and Gram-negative enteric bacilli and Pseudomonas/Stenotrophomonas species were present in 30%. All five isolates of Streptococcus pneumoniae were resistant to penicillin (three intermediately and two highly), and three were resistant to multiple antibiotics. Pseudomonas species revealed multiresistance in four of nine isolates (44%), and Stenotrophomonas maltophilia revealed multiresistance in one of two isolates. Antimicrobial treatment was modified according to diagnostic results in 11 of 31 patients (36%) with potentially pathogenic microorganisms. In patients who underwent a repeat investigation after 72 hrs, 24% of the initially present and potentially pathogenic microorganisms persisted. Inappropriate initial antimicrobial therapy was associated significantly with bacterial persistence (p < .002). CONCLUSIONS: Considering the diversity of microbial pathogens and the resistance rates especially to S. pneumoniae in this patient population, antimicrobial treatment should be based on the constant study of local microbial and susceptibility patterns along with routine microbial investigation of the individual patient.

Aged↗
PubMedDate not supplied

Infection prophylaxis for the patient with cancer.

Despite major advances in treatment, patients with cancer still are plagued by infections. Anti-infection prophylaxis begins with attempts to enhance host defenses, minimize natural barrier alterations, and reduce the number of pathogenic organisms in the patient's environment. Prevention of infection via immunomodulation also is effective to some extent. Immunoglobulin administration, leukocyte transfusion, vaccines, and lithium carbonate are integral parts of this approach to prophylaxis. Antimicrobial modulation also has been attempted. Oral nonabsorbable antibiotics have been used to reduce the number of potentially pathogenic gastrointestinal organisms. Systemic antibiotics have been evaluated for their prophylactic efficacy in patients with cancer. Obstacles to effective systemic prophylaxis include the risk of developing resistant populations of microorganisms and the inordinately large number of potentially pathogenic organisms. The oncology nurse must assume specific responsibilities when administrating prophylactic regimens. There are three crucial issues to be considered: risk factors, aspects of cost and reimbursement, and availability of the most recent treatment options.

Anti-Bacterial Agents↗
PubMed1997

Randomized studies with interferon in chronic myelogenous leukemia (CML) and comparative molecular aspects. German CML Study Group.

Four randomized prospective studies on interferon alpha (IFN) in CML report varying degrees of prolongation of the chronic phase of CML and of survival as compared to conventional therapies. There is agreement that IFN prolongs survival as compared to standard busulfan. There is disagreement, however, as to which degree IFN is superior to hydroxyurea. Whereas the randomized studies of the Italian cooperative group and of the British MRC find a statistically significant survival advantage of IFN over hydroxyurea of about 20 months, this difference is only 10 months in the German randomized study and not significant. One reason for this difference might be the more intensive treatment schedule for the hydroxyurea control group in the German study. Other reasons might be differences in risk profiles between the patient groups studied and in strategies of IFN therapy. About 1% of the human genome consists of retroviral or retroviral-like sequences. By analogy to animal models, endogenous retroviruses might also have pathogenic potential in human disease. The transposon-like structure of retroviruses that enables them to integrate at almost any position in the host genome and the capability of retroviruses to serve as efficient vehicles of cellular genes are in support of a pathogenic potential. Furthermore, particles resembling retroviruses have been observed long ago in human embryonic and malignant tissues and cell lines. Sequence information and the transcriptional activity of the endogenous sequences argue against the possibility that these sequences are only fossil relics of early evolutionary periods. Most of the sequences appear to be inactivated by stop codons or frameshifts, making the genomic localization of open reading frames with biological activity difficult. Up to now, mutagenesis by insertion of retroviral-like sequences in sporadic cases of human disease appears to be the only example of pathogenic relevance of retroviruses in man.

Antineoplastic Agents↗
PubMed1983

The significance of group B streptococci in neonatal pneumonia.

Thirty-eight infants admitted to a neonatal intensive care unit because of pneumonia (14 patients) and pulmonary maladaption syndrome (PMA) (24 patients) were included in the study. Samples of potentially pathogenic, facultatively anaerobic bacteria were taken from the external ear, blood, throat, nasopharynx, umbilicus and gastric aspirates of the children, and from urethra and cervix of the mothers. Group B streptococci (GBS) and Escherichia coli were the only potentially pathogenic bacteria isolated from the infants. Out of 14 infants with pneumonia 11 (79%) harboured one of these bacteria, in contrast to 3 out of 24 (13%) with PMA (P less than 0.001). GBS was found in 8/14 infants with pneumonia and in 1/24 infants with PMA (P less than 0.001). The respective frequencies for Escherichia coli were 3/14 and 2/24 (not significant). The infant and/or the mother in 10/14 pneumonia cases harboured GBS, in contrast to 4/24 pairs in the PMA group (P less than 0.001). The levels of antibodies against GBS in sera of mothers to infants with pneumonia did not differ from the antibody levels in control sera (parturient GBS-carriers giving birth to healthy infants). The results gave evidence for an important manifestation of neonatal GBS-infection: pneumonia without septicemia. The incidence of the disease is estimated to be 1:25 parturient GBS-carriers. Finally, maternal fever, gestational age above 42 weeks, more severe respiratory difficulties and the occurrence of severe changes in fetal heart rate during the first stage of labour were found to be typical characteristics of pneumonia, as compared to PMA.

Escherichia coli↗