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1.
Am J Infect Control ; 27(5): 392-401, 1999 Oct.
Article in English | MEDLINE | ID: mdl-10511485

ABSTRACT

BACKGROUND: The soiling levels of patient-used narrow-lumened flexible endoscopes were assessed for bronchoscopes, duodenoscopes, and colonoscopes. The effect of cleaning on the soil composition and concentration was evaluated. DESIGN: Suction channels from 10 each of bronchoscopes, duodenoscopes used for endoscopic retrograde cholangiopancreatography, and colonoscopes were assessed immediately after patient use for the levels of bilirubin, hemoglobin, protein, sodium ion, carbohydrate, endotoxin, and viable bacteria. Another 10 suction channels of each type of endoscope were evaluated for the same components after routine cleaning but before processing by high-level disinfection or sterilization for subsequent clinical use. RESULTS: Recognizing that only soluble components could be quantified, the worst-case soil levels in the suction channels (the average surface area of these channels was 45.6 cm(2), 149.8 cm,(2) and 192.0 cm(2) for bronchoscopes, duodenoscopes, and colonoscopes, respectively) were protein 115 microg/cm(2), sodium ion 7.4 micromol/cm(2), hemoglobin 85 microg/cm(2), bilirubin 299 nmol/cm(2), carbohydrate 29.1 microg/cm(2), endotoxin 9852 endotoxin units/cm(2), and bacteria 7.1 (log(10)) colony-forming units (CFU)/cm(2). Colonoscopes had 4 to 5 times greater soiling on average compared with the other endoscope types. Routine cleaning reduced the levels of bilirubin to below the limits of detection for all endoscopes evaluated (limits of detection were <1 nmol/mL). After cleaning, residual hemoglobin was detectable in bronchoscopes only. After cleaning, the levels of protein, endotoxin, and sodium ion all were reduced fivefold to tenfold for all types of endoscopes. Carbohydrate was reduced to lower than the limit of detection for all endoscopes after cleaning, except the duodenoscopes. The average load of viable bacteria was reduced from 3 log(10) to 5 log(10) CFU/cm(2) (which represents 5.9-9.5 log(10) CFU/endoscope channel) after patient use to approximately 2 log(10) CFU/cm(2) (which represents 3.2-5.3 log(10) CFU/endoscope channel) after cleaning. CONCLUSIONS: These data demonstrated that cleaning effectively reduced or eliminated many components of soil, but a substantial amount of viable bacteria and protein remained. Hemoglobin levels in before samples indicated that blood was not present in high concentrations in the suction channels of the majority of flexible endoscope samples. Soil that mimics the worst-case composition from patient-used endoscopes would be ideal for simulated-use studies for such medical devices.


Subject(s)
Bronchoscopes , Colonoscopes , Duodenoscopes , Equipment Contamination/statistics & numerical data , Disinfection , Equipment Reuse , Humans , Linear Models , Sterilization , Suction
2.
Can J Infect Dis ; 10(4): 287-94, 1999 Jul.
Article in English | MEDLINE | ID: mdl-22346388

ABSTRACT

OBJECTIVE: To monitor prospectively patients with Clostridium difficile-associated diarrhea (CAD) in a six hundred bed tertiary care hospital to determine which factors influenced the recurrence of the diarrhea. DESIGN: A prospective, nonrandomized study. After an initial diagnosis of CAD, patients were interviewed, and each week stool samples and environmental samples were monitored for the presence of toxigenic C difficile for as long as the patients remained in hospital. The relationship of concurrent antibiotics, prolonged fecal excretion of organism or toxin, and environmental contamination was assessed. PATIENTS: Over a two-and-a-half year period, 75 consecutive patients with CAD were selected and those who gave their written informed consent were enrolled. A control group to evaluate environmental contamination consisted of 75 patients with diarrhea not associated with C difficile. RESULTS: Of the 75 CAD patients, 11 (14.7%) had a recurrence of their diarrhea. Diarrhea recurrence was associated with an increased rate of prolonged excretion of toxigenic organism and/or C difficile toxin(s) (nine of 11 [81.8%] compared with nine of 64 [14.1%]; P≤0.0001; relative risk 14.25; 95% CI 3.383 to 60.023). The risk of diarrhea recurrence was not related to a specific antibiotic but to concurrent therapy. Treatment within 30 days of initial CAD-specific treatment with an antibiotic other than metronidazole or vancomycin occurred significantly more frequently in patients with recurrence of diarrhea compared with those who did not have a recurrence (eight of 11 [72.7%] compared with 22 of 64 [34.4%], P=0.022; relative risk 4; 95% CI 1.153 to 13.881). The environmental contamination rate for toxigenic C difficile in week one in the rooms of patients with diarrhea not caused by C difficile was low (two of 75 [2.6%]) compared with week one data for patients with CAD (14 of 75 [18.7%], P=0.002; relative risk 1.922; 95% CI 1.479 to 2.498). The most frequent site contaminated was the bedpan sprayer (eight of 14 [57.1%]). Pulsed field gel electrophoresis analysis of stool and environmental toxigenic isolates indicated that there was not a single endemic strain of C difficile. CONCLUSIONS: This study indicates that the recurrence of diarrhea may be related to concurrent 'other' antibiotics. Although data indicated that there was a correlation between diarrhea recurrence and prolonged fecal excretion of toxin, further studies are required to clarify the clinical significance.

3.
Am J Infect Control ; 26(5): 469-77, 1998 Oct.
Article in English | MEDLINE | ID: mdl-9795674

ABSTRACT

The aim of this study was to determine how well peracetic acid liquid chemical sterilization (LCPAS) killed test organisms in the presence of 10% fetal bovine serum and 0.65% salt challenge (RPMI-S) compared with a 100% ethylene oxide (ETO) sterilizer and an ETO hydrochlorofluorocarbon (ETO-HCFC) sterilization method with long (125 cm), narrow (3-mm internal diameter) flexible lumens as the test carrier. The inoculated lumens were dried overnight before processing. The test organisms included Mycobacterium chelonei, Enterococcus faecalis, and Bacillus subtilis. For all 3 organisms tested, the LCPAS process resulted in a 6 log10 reduction in bacterial load compared with a 2.5 log10 to 6 log10 reduction for the 100% ETO and ETO-HCFC sterilizers. Sterilization was achieved for 100%, 61%, and 67% of the lumen test carriers for the LCPAS, 100% ETO, and ETO-HCFC sterilizers, respectively. The data indicate that of the sterilization methods evaluated, LCPAS was the most effective for sterilizing narrow flexible lumens in the presence of residual inorganic and organic soil. This effectiveness was achieved through a combination of organism wash-off and peracetic acid sterilant killing of organisms. Salt was the major compounding factor for effective ETO gas sterilization, because carriers inoculated with organisms in 10% fetal bovine serum alone all were sterilized by both 100% ETO and ETO-HCFC sterilization methods. Our data support the critical need to ensure adequate precleaning of narrow flexible lumen endoscopes before any sterilization method.


Subject(s)
Disinfectants , Endoscopes/microbiology , Ethylene Oxide , Peracetic Acid , Sterilization/methods , Bacillus subtilis/growth & development , Enterococcus faecalis/growth & development , Mycobacterium chelonae/growth & development , Sterilization/instrumentation
4.
Infect Control Hosp Epidemiol ; 18(9): 641-5, 1997 Sep.
Article in English | MEDLINE | ID: mdl-9309437

ABSTRACT

OBJECTIVES: To use a serum and salt challenge in narrow-lumen carriers to evaluate a 10% ethylene oxide plus 90% hydrochlorofluorocarbon (EO-HCFC) sterilant mixture in a retrofitted 12/88 sterilizer as an alternative to the banned chlorofluorocarbon-ethylene oxide (EO) sterilant mixture. DESIGN: An EO-HCFC sterilizing gas mixture in a retrofitted 12/88 sterilizer was compared to 100% ethylene oxide (100% EO) sterilizing gas to determine its relative ability to kill seven different bacteria (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Bacillus subtilis spores, Bacillus stearothermophilus spores, Bacillus circulans spores, and Mycobacterium chelonei) in the presence or absence of a combined 10% serum and 0.65% salt challenge using both penicylinders (PC) and long narrow-lumen (LU) carriers. RESULTS: The EO-HCFC sterilant mixture (96% sterile carriers) was equivalent to the 100% EO sterilant (98% sterile carriers) for killing vegetative organisms, as well as spore suspensions, on the 27 PC and 27 LU carriers in the absence of serum and salt. In the presence of serum and salt, the EO-HCFC sterilant mixture was markedly better than the 100% EO sterilant at reducing the bacterial load on the 63 PC carriers (95% vs 62% sterile PC carriers, respectively), whereas both sterilizers were equivalent for the 63 LU carriers (49% vs 40% sterile LU carriers, respectively). Of the seven test organisms, E faecalis, B subtilis, B stearothermophilus, and B circulans were the most difficult to kill for both PC and LU carriers when serum and salt were present. CONCLUSIONS: The data presented in this report indicate that the EO-HCFC sterilant mixture is an effective alternative for gas sterilization. Indeed, the efficiency of bacterial killing for the EO-HCFC sterilant mixture was similar to that achieved by the 12/88 EO-CFC sterilant mixture.


Subject(s)
Bacteria/drug effects , Chlorofluorocarbons, Methane/pharmacology , Ethylene Oxide/pharmacology , Sterilization/methods , Colony Count, Microbial , Humans , Microbial Sensitivity Tests
5.
J Clin Microbiol ; 35(4): 862-6, 1997 Apr.
Article in English | MEDLINE | ID: mdl-9157143

ABSTRACT

Culture-negative peritonitis is a major complication for patients on continuous ambulatory peritoneal dialysis (CAPD) and precludes organism-specific therapy. The aim of the present study was to compare inoculation of 10 ml of CAPD effluent into BacT/Alert blood culture bottles (FAN [fastidious antimicrobic neutralizing], BacTAlert aerobic [BTA], and BacT/Alert anaerobic [BTAn] bottles) to our conventional method of using 50 ml of concentrated CAPD effluent to inoculate peptone broth bottles (BD bottles) and MacConkey agar and blood agar medium (BA-MAC). The FAN, BTA, and BTAn bottles were monitored automatically in the BacT/Alert blood culture instrument. A total of 207 CAPD effluents were studied, and in 97 bacteria were detected by at least one method. Compared to BTA bottles (79 of 97; 81.4%), BTAn bottles (78 of 97; 80.4%), and BD bottles (88 of 97; 90.7%), the single best broth medium for detecting bacterial growth in CAPD effluents was the FAN bottle (90 of 97 effluents; 92.8%). A total of 125 bacterial species were detected by any method, and the majority (91.8%) of CAPD effluents were infected with a single species. A combination of FAN and BTAn bottles detected 111 of 125 (88.8%) of all organisms, whereas a combination of BD bottles and BA-MAC detected 107 of 125 (85.6%) of all organisms. One or more organisms that would have been completely missed by the conventional method with BD bottles and BA-MAC were detected in 18 CAPD effluents. Of these 18 CAPD effluents, 6 showed no growth by the conventional method with BD bottles and BA-MAC. On the basis of our data, the most sensitive and least labor intensive method was direct inoculation of 10 ml of CAPD effluent into a FAN bottle and a BTAn bottle, which could be automatically monitored by the BacT/Alert blood culture instrument. On the basis of case definitions for peritonitis, the sensitivities and specificities of the methods with FAN and BTAn bottles and with BD bottles and BA-MAC were 81.1 and 98.8% and 74.5 and 96.5%, respectively.


Subject(s)
Bacteria/isolation & purification , Bacterial Infections/microbiology , Bacterial Typing Techniques/instrumentation , Peritoneal Dialysis, Continuous Ambulatory/adverse effects , Bacterial Infections/diagnosis , Bacterial Infections/etiology , Humans
6.
Microb Pathog ; 22(1): 39-46, 1997 Jan.
Article in English | MEDLINE | ID: mdl-9032761

ABSTRACT

Haemophilus ducreyi is the causative agent of the genital ulcer disease Chancroid. Chancroid has been shown to increase the risk of heterosexual transmission of HIV. Little is known regarding the attachment or localization of this organism to human cells in either the dermal or epidermal layer. In this study the attachment of H. ducreyi to human foreskin fibroblast (HFF) cells was further characterized. Attachment was mediated by more than one mechanism. Proteinase K treatment but not trypsinization of H. ducreyi significantly reduced attachment suggesting protein involvement. In addition, purified lipooligosaccharide (LOS) was able to inhibit attachment in a dose dependent manner. It appeared that the organism binds to fibronectin in the extracellular matrix of HFF cells, since competition studies using fibronectin showed that it was able to significantly reduce attachment in a dose dependent manner whereas collagen did not. We hypothesize that the attachment of H. ducreyi involves both a protein mediator of attachment (likely pili) as well as LOS and that one or both of these bacterial components interacts with fibronectin in the extracellular matrix to mediate attachment to HFF cells.


Subject(s)
Bacterial Adhesion/drug effects , Chancroid/microbiology , Fibronectins/pharmacology , Haemophilus ducreyi/metabolism , Lipopolysaccharides/pharmacology , Antibodies, Monoclonal/pharmacology , Azides/pharmacology , Cells, Cultured , Collagen/pharmacology , Cycloheximide/pharmacology , Cytochalasin B/pharmacology , Dose-Response Relationship, Drug , Endopeptidase K/pharmacology , Extracellular Matrix/metabolism , Fibroblasts/ultrastructure , Flow Cytometry , Haemophilus ducreyi/drug effects , Haemophilus ducreyi/pathogenicity , Humans , Microscopy, Electron , Polymyxin B/pharmacology , Sialic Acids/pharmacology , Trypsin/pharmacology
7.
Infect Immun ; 64(6): 2349-52, 1996 Jun.
Article in English | MEDLINE | ID: mdl-8675349

ABSTRACT

Haemophilus ducreyi, which causes the sexually transmitted disease chancroid, produces several factors that damage human cells. We used isogenic mutants of H. ducreyi 35000 to demonstrate that the hemolytic activity and the cytotoxic effect of H. ducreyi on human foreskin fibroblasts are due to the same toxin.


Subject(s)
Cytotoxins/toxicity , Haemophilus ducreyi/pathogenicity , Hemolysin Proteins/toxicity , Cells, Cultured , Humans
8.
Infect Control Hosp Epidemiol ; 17(2): 92-100, 1996 Feb.
Article in English | MEDLINE | ID: mdl-8835444

ABSTRACT

OBJECTIVE: The performance of a standard gas sterilizer, which uses a mixture of 12% ethylene oxide (EtO) and 88% chlorofluorocarbon as the sterilizing gas (12/88), was compared to selected gas, ion plasma, and vaporized hydrogen peroxide (H2O2) sterilizers that do not use chlorofluorocarbons. The effect of serum and salt on sterilizer performance was evaluated. DESIGN: Test carriers (porcelain and stainless steel penicylinders, or 125-cm lengths of plastic tubing [internal diameter of 3.2 mm]) were inoculated with Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa, Mycobacterium chelonei, Bacillus stearothermophilus spores, Bacillus subtilis spores, and Bacillus circulans spores and then subjected to sterilization using 12/88, 100% EtO, ion plasma, or vaporized H2O2. The bacterial inoculum was prepared with and without 10% serum and 0.65% salt, and the residual bacterial load after sterilization as determined using viable counts. RESULTS: All of the sterilizers tested effected a six-log10 reduction of the bacterial inoculum on penicylinders, unless 10% serum and 0.65% salt were present, in which case the 100% EtO, vaporized H2O2, and ion plasma sterilizers were not as effective as the 12/88 sterilizer. None of the sterilizers could eradicate 10(6) CFU of all of the bacteria in 10% serum and 0.65% salt when inoculated inside a narrow lumen. CONCLUSIONS: The margin of safety for the 100% EtO, vaporized H2O2, and ion plasma sterilizers is less than that of the 12/88 sterilizer. The inability of all sterilizers, including the 12/88, to kill organisms in narrow lumens reliably when serum and salt were present raises concern about the current practice of gas sterilization of flexible endoscopes.


Subject(s)
Chlorofluorocarbons , Ethylene Oxide , Hydrogen Peroxide , Sterilization/instrumentation , Analysis of Variance , Colony Count, Microbial , Endoscopy , Gases , Sterilization/methods , Sterilization/standards , Technology Assessment, Biomedical/methods , Temperature , Volatilization
9.
Infect Immun ; 63(5): 1754-61, 1995 May.
Article in English | MEDLINE | ID: mdl-7729882

ABSTRACT

To identify virulence-associated properties of Haemophilus ducreyi, 34 strains of this sexually transmitted pathogen were evaluated for in vitro phenotypic characteristics of potential relevance to chancroid pathogenesis and for their ability to produce lesions in the temperature-dependent animal model for chancroid. Of the 34 strains tested, all but three produced a cytopathic effect on human foreskin fibroblasts (HFF) and all but six strains formed large microcolonies on HFF monolayers. A subset of 12 selected strains underwent more extensive analyses and, when evaluated for both their cytadherence kinetics and growth in the presence of HFF monolayers, it was found that several of these strains had a very limited ability to attach to HFF cells. When the same 12 strains were tested in the temperature-dependent rabbit model, only the seven strains which were positive in all of these in vitro-based tests readily produced lesions. In contrast, the five strains that were noted to be deficient in one or more of the phenotypic characteristics scored in the in vitro systems did not produce lesions. This association between the traits measured in vitro and the ability to produce dermal lesions was significant (P = 0.0012). These results suggest that in vitro behavior may be used to predict the virulence potential of H. ducreyi strains. Moreover, the phenotypic characteristics described in this study are appropriate focal points for efforts to determine the molecular basis of the virulence of this pathogen.


Subject(s)
Haemophilus ducreyi/pathogenicity , Animals , Bacterial Adhesion , Cells, Cultured , Chancroid/etiology , Chancroid/microbiology , Culture Techniques , Disease Models, Animal , Male , Phenotype , Rabbits , Skin/cytology , Skin/growth & development , Skin/microbiology , Skin/pathology
10.
Pediatr Infect Dis J ; 14(5): 341-5, 1995 May.
Article in English | MEDLINE | ID: mdl-7638006

ABSTRACT

This study assessed maternal genital colonization and subsequent neonatal transmission rate of Ureaplasma urealyticum in pregnant women in an average socioeconomic population. In addition very low birth weight infants were assessed to determine whether the presence of U. urealyticum correlated with increased risk of developing respiratory problems. The study group consisted of 108 sequential full term mothers and 104 preterm mothers delivering in a tertiary care hospital in central Canada. The genital carriage rates (assessed using placental sampling) of ureaplasmas in term and preterm mothers were 25.9 and 19.2%, respectively (P = 0.3185). Acquisition of ureaplasmas in the neonatal respiratory tract of neonates occurred significantly (P = 0.0182) more often in preterm neonates (11 of 130; 8.5%) than in term neonates (2 of 110; 0.9%). Very low birth weight (VLBW) infants (< or = 1500 g) were at greater risk (P = 0.042) of acquiring ureaplasmas in their respiratory tracts (5 of 26; 19%) than larger preterm neonates (6 of 104; 5.8%). All VLBW infants with respiratory colonization by ureaplasmas (5 of 5) developed bronchopulmonary dysplasia compared with 33% (7 of 21) of VLBW neonates without ureaplasmas (P = 0.028). This difference in bronchopulmonary dysplasia development among VLBW infants was independent of further stratification by birth weight. These VLBW neonates with ureaplasmas also stayed significantly (P = 0.037) longer in the neonatal intensive care unit (43.6 +/- 10.4 days) than did other preterm neonates (22.1 +/- 20.8 days). Our results demonstrate that VLBW preterm neonates have increased risk of acquiring U. urealyticum.(ABSTRACT TRUNCATED AT 250 WORDS)


Subject(s)
Bronchopulmonary Dysplasia/etiology , Infant, Premature, Diseases/etiology , Infectious Disease Transmission, Vertical , Pregnancy Complications, Infectious , Ureaplasma Infections/transmission , Ureaplasma urealyticum/isolation & purification , Adult , Bronchopulmonary Dysplasia/epidemiology , Colony Count, Microbial , Female , Humans , Infant, Low Birth Weight , Infant, Newborn , Infant, Premature , Infant, Premature, Diseases/epidemiology , Infectious Disease Transmission, Vertical/statistics & numerical data , Male , Pregnancy , Pregnancy Complications, Infectious/diagnosis , Pregnancy Complications, Infectious/epidemiology , Risk Factors , Socioeconomic Factors , Ureaplasma Infections/diagnosis , Ureaplasma Infections/epidemiology
11.
Microb Pathog ; 17(3): 167-74, 1994 Sep.
Article in English | MEDLINE | ID: mdl-7700133

ABSTRACT

This study evaluated a commercially available chemiluminescent-labelled, ribosomal RNA-directed DNA probe (CRP) as a method to quantitate attachment of H. ducreyi to human foreskin fibroblast (HFF) cells. Evaluation of four strains of H. ducreyi demonstrated that the CRP assay was unaffected by eukaryotic cells and its advantages were: (i) quantitation was done after attachment so it did not interfere with the attachment process, and (ii) it was a rapid, reliable method for quantitating bound bacteria, despite bacterial clumping. Gentamicin-killed H. ducreyi attached to both HFF cells and viable controls, suggesting that the adhesins are components constitutively present on the surface of H. ducreyi. This method may be widely applicable, since the probe recognizes most prokaryotic rRNA sequences.


Subject(s)
Bacterial Adhesion , DNA Probes , Haemophilus ducreyi/growth & development , RNA, Ribosomal , Cell Line , Colony Count, Microbial , Fibroblasts/microbiology , Haemophilus ducreyi/classification , Humans , Luminescent Measurements , Male , Polymerase Chain Reaction
12.
Sex Transm Dis ; 21(5): 247-57, 1994.
Article in English | MEDLINE | ID: mdl-7817258

ABSTRACT

BACKGROUND AND OBJECTIVES: Haemophilus ducreyi is the etiologic agent of chancroid, which is a genital ulcer disease that increases the risk of acquiring and transmitting HIV. The pathogenesis of H. ducreyi is not well understood. GOAL OF THIS STUDY: The goal of this study was to use a quantitative tetrazolium-based XTT assay to characterize the cytopathic effect of H. ducreyi on human foreskin fibroblasts. STUDY DESIGN: Haemophilus ducreyi strains 35000, R018, A77 and CIP542 were evaluated using the XTT assay. The role of attachment on resultant CPE was assessed using a wash step 2 hours post-infection. Internalization was evaluated by the gentamicin kill assay. Secreted exotoxin was studied using permeable inserts to separate the bacteria from the HFF monolayer. RESULTS: HFF cell damage did not appear to be mediated by a secreted H. ducreyi cytotoxin. Direct contact of viable H. ducreyi with HFF cells was required for cell damage. H. ducreyi strains that attached poorly could be readily removed by a wash step. This reduced their capacity to damage HFF cells significantly. Although some H. ducreyi strains attach to high levels within 4 hours, no HFF cell damage was detected by the XTT assay. However, once HFF cell damage was detected by 24 hours, it was not easily reversible, despite antibiotic treatment that eradicated H. ducreyi. Internalization of H. ducreyi by HFF cells apparently did not occur to a significant degree. CONCLUSION: This study indicates that classic "soluble exotoxins" are not likely the key component in H. ducreyi pathogenesis. Attachment or direct contact with HFF cells are required for H. ducreyi to cause a CPE.


Subject(s)
Exotoxins/metabolism , Fibroblasts/microbiology , Haemophilus ducreyi/pathogenicity , Bacterial Adhesion , Biological Assay , Cell Line , Cells, Cultured , Evaluation Studies as Topic , Haemophilus ducreyi/classification , Haemophilus ducreyi/physiology , Humans , Indicators and Reagents , Male , Penis/cytology , Serotyping , Tetrazolium Salts
13.
J Infect Dis ; 167(5): 1206-10, 1993 May.
Article in English | MEDLINE | ID: mdl-8486955

ABSTRACT

The humoral immune response to purified lipooligosaccharide (LOS) and outer membrane proteins (OMP) of Haemophilus ducreyi was evaluated. Sera from chancroid-endemic (Uganda, Kenya) and -nonendemic (Canada) countries were tested by an ELISA. The response to OMPs was cross-reactive with other Haemophilus species, and elevated levels of antibody were detected in patients that did not have chancroid. The LOS component stimulated an H. ducreyi-specific immune response that was detected only in patients with chancroid. The sensitivity of the LOS ELISA was 96% (95% confidence interval, 89.9%-100%) and the specificity was 97% (95% confidence interval, 95.8%-98.2%). Thus, the anti-H. ducreyi LOS immune response is a significant diagnostic and epidemiologic indicator.


Subject(s)
Antibodies, Bacterial/immunology , Bacterial Outer Membrane Proteins/immunology , Chancroid/immunology , Haemophilus ducreyi/immunology , Lipopolysaccharides/immunology , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Infant , Male
14.
Infect Immun ; 61(5): 1735-42, 1993 May.
Article in English | MEDLINE | ID: mdl-8478062

ABSTRACT

Haemophilus ducreyi is the etiologic agent of the localized genital ulcer disease known as chancroid. The pathogenesis of this organism is poorly understood. The role of attachment in the disease process has not been evaluated. In this study, 125I-H. ducreyi was used to quantitatively evaluate the interaction of virulent and avirulent H. ducreyi strains with human foreskin cells. Using this in vitro model system, we demonstrated that, at 22 and 35 degrees C, the attachment of virulent H. ducreyi 35000 to human foreskin cells was significantly more marked than that of avirulent H. ducreyi A77. Although H. ducreyi penetrated between human foreskin cells, internalization was not a major component. Our competition assay data suggest that the attachment mechanism of H. ducreyi may be similar to that of Neisseria gonorrhoeae. We speculate that the attachment and microcolony formation of virulent H. ducreyi may provide a mechanism for bacterial localization and evasion of host defenses.


Subject(s)
Bacterial Adhesion , Chancroid/microbiology , Haemophilus ducreyi/pathogenicity , Penis/microbiology , Bacterial Proteins/analysis , Cell Line , Epithelium/microbiology , Haemophilus ducreyi/chemistry , Humans , In Vitro Techniques , Male , Microscopy, Electron , Microscopy, Electron, Scanning , Temperature
15.
Sex Transm Dis ; 19(6): 309-14, 1992.
Article in English | MEDLINE | ID: mdl-1492255

ABSTRACT

Serodiagnosis of chancroid is limited by the cross-reactivity of Haemophilus ducreyi with Haemophilus influenzae and Haemophilus parainfluenzae. This research describes an adsorption enzyme immunoassay (EIA) that assesses the humoral immune response of North Americans and Africans to H. ducreyi. Adsorption effectively removed anti-H. influenzae and anti-H. parainfluenzae antibodies, revealing that North American control sera had no residual anti-H. ducreyi reactivity. However, African control sera still had a residual anti-H. ducreyi response. Assessment of the duration of the humoral immune response in sera from African patients with chancroid showed that the humoral antibodies persisted for up to 8 months after the diagnosis. This may explain the lack of specificity of the adsorption EIA in areas where chancroid is endemic. The detection of the humoral immune response was affected by the strain of H. ducreyi used, with indigent strains being most useful. Using H. ducreyi 35000 for Canadian sera, the sensitivity of the adsorption EIA was 100% and the specificity was 88%. For African sera, H. ducreyi strain R018 was used, and the adsorption EIA had a sensitivity of 81% and a specificity of only 23%. These data reveal that the existing humoral response in a country where chancroid is endemic differs from that in a country where it is not, and that care must be used interpreting unadsorbed humoral immune responses. The adsorption EIA approach may prove useful as an epidemiologic tool for definition of existing (past and present) levels of exposure to H. ducreyi.


Subject(s)
Antibody Formation , Antibody Specificity , Chancroid/immunology , Haemophilus ducreyi/immunology , Immunoenzyme Techniques , Adolescent , Adult , Canada , Chancroid/diagnosis , Child , Child, Preschool , Cross Reactions , Female , Humans , Immunoglobulin A/biosynthesis , Immunoglobulin G/biosynthesis , Immunoglobulin M/biosynthesis , Infant , Infant, Newborn , Kenya , Male , Time Factors , Uganda
16.
Can J Infect Dis ; 3(4): 173-8, 1992 Jul.
Article in English | MEDLINE | ID: mdl-22514366

ABSTRACT

The authors compared the activity of daptomycin with that of ampicillin, penicillin, teicoplanin and vancomycin against 304 strains of Enterococcus species isolated from blood and urine. Daptomycin was as active as penicillin against Enterococcus faecalis: 90% of strains were inhibited by 2 mg/L. Daptomycin was more active than vancomycin (90% minimal inhibitory concentration [MIC(90)] 2 mg/L; 90% minimal bactericidal concentration [MBC(90)] 8 mg/L) but was less active than teicoplanin (MIC(50) 0.25; MBC(90) 8 mg/L) or ampicillin (MIC(90) 1 mg/L; MBC(90) 2 mg/L) against E faecalis. In time-kill studies daptomycin was not more rapidly bactericidal than ampicillin or penicillin but was significantly more rapidly bactericidal than either teicoplanin or vancomycin. In combination with gentamicin, daptomycin has activity similar to that of penicillin, vancomycin and teicoplanin. Daptomycin may be a suitable alternative to penicillin in patients allergic to penicillins or for the treatment of enterococcal infections caused by beta-lactamase-producing enterococci.

17.
Can J Infect Dis ; 1(3): 97-100, 1990.
Article in English | MEDLINE | ID: mdl-22553449

ABSTRACT

The proportion of enterococci isolated from blood and urine cultures that were highly resistant to gentamicin and streptomycin were determined. No blood or urine isolates highly resistant to gentamicin were seen in 1983, whereas by 1986-87 25% of blood and 17% of urine isolates were highly resistant. The rapid emergence of gentamicin resistance has serious implications for patients with life threatening enterococcal disease.

18.
Diagn Microbiol Infect Dis ; 12(5): 437-40, 1989.
Article in English | MEDLINE | ID: mdl-2515026

ABSTRACT

We compared the in vitro activity of lomefloxacin with that of other agents against 336 strains of Haemophilus influenzae and Branhamella catarrhalis isolated from the respiratory tract of a predominantly adult and in-patient population. H. influenzae strains were usually not serotypable. No strains were resistant to lomefloxacin; all strains tested were susceptible to 0.25 micrograms/ml. The lomefloxacin MIC50 and MIC90 was 0.125 micrograms/ml.


Subject(s)
Anti-Bacterial Agents/pharmacology , Fluoroquinolones , Haemophilus influenzae/drug effects , Moraxella catarrhalis/drug effects , Quinolones , 4-Quinolones , Administration, Oral , Anti-Bacterial Agents/administration & dosage , Humans
19.
Diagn Microbiol Infect Dis ; 12(3 Suppl): 83S-86S, 1989.
Article in English | MEDLINE | ID: mdl-2507222

ABSTRACT

The in vitro activity of lomefloxacin, a new difluorinated quinolone antimicrobial was compared to comparative agents against organisms causing sexually transmitted diseases. Against Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum, Neisseria gonorrhoeae, and Haemophilus ducreyi, lomefloxacin exhibited MIC90 of 2.0, 8.0, 8.0, less than or equal to 0.015, and 0.003 micrograms/ml, respectively. Overall, the lomefloxacin activity was very similar to ciprofloxacin.


Subject(s)
Anti-Infective Agents/pharmacology , Bacteria/drug effects , Fluoroquinolones , Quinolones , 4-Quinolones , Bacteria/isolation & purification , Chlamydia trachomatis/drug effects , Chlamydia trachomatis/isolation & purification , Evaluation Studies as Topic , Haemophilus/drug effects , Haemophilus/isolation & purification , Humans , Microbial Sensitivity Tests , Mycoplasma/drug effects , Mycoplasma/isolation & purification , Neisseria gonorrhoeae/drug effects , Neisseria gonorrhoeae/isolation & purification , Sexually Transmitted Diseases, Bacterial/diagnosis , Sexually Transmitted Diseases, Bacterial/microbiology , Ureaplasma
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