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Biomedical subjects

D N Gerding

Publications and source records attributed to D N Gerding.

At least 109 records · Page 6Linked to original sources
PubMed1986

Efficacy of routine fiberoptic endoscope cleaning and disinfection for killing Clostridium difficile.

We have evaluated a standard procedure for cleaning and disinfection of endoscopes for efficacy in eradicating a spore-forming bacterial organism, Clostridium difficile. Initially, 23 endoscopes were cultured for the presence of C. difficile after hanging in storage for at least 24 hours after cleaning and disinfection. All cultures were negative. Subsequently, endoscopes used in 15 patients who had stool cultures positive for C. difficile were cultured immediately after use and again after cleaning and disinfection with 2% alkaline glutaraldehyde for 5 min. Ten of 15 (67%) endoscopes were culture positive for C. difficile immediately after use. After cleaning and disinfection, all of the endoscopes were culture negative except one, which yielded two negative cultures and two cultures showing late growth of rare C. difficile colonies, but contamination could not be ruled out. In vitro exposure to 2% alkaline glutaraldehyde for 5 min resulted in 99% or greater killing of C. difficile spores. We conclude that cleaning and a minimum of 5 min of disinfection with 2% alkaline glutaraldehyde are likely to be effective in killing C. difficile vegetative organisms and spores on endoscopes.

Aldehydes↗
PubMed1986

Detection of Clostridium difficile toxins A (enterotoxin) and B (cytotoxin) in clinical specimens. Evaluation of a latex agglutination test.

A new latex test, Culturette Brand Rapid Latex Test for detection of Clostridium difficile toxin A, was tested on 408 stool samples. In 247 frozen tissue culture supernate specimens previously obtained from patients with C. difficile-associated diarrhea (CAD), the latex test (enterotoxin) was positive in 182 (74%) as compared with 194 (79%) for the repeat tissue culture (P greater than 0.1) cytotoxin (toxin B) test. Testing of 161 fresh stool samples found the latex test superior to tissue culture (P less than 0.05) in cases of CAD (90% positivity vs. 70%), with the two tests being equal in both non-CAD diarrheal and non-diarrheal control groups. In vitro evaluation of 61 C. difficile isolates found all (100%) to be producers of enterotoxin A, while only 53 (87%) produced toxin B. The latex test for C. difficile toxin detection is a rapid, simple test for use in the diagnosis in CAD.

Bacterial Toxins↗
PubMed1986

Bacterial agglutination and polyacrylamide gel electrophoresis for typing Clostridium difficile.

Bacterial agglutination and polyacrylamide gel electrophoresis (PAGE) were methods evaluated for typing strains of Clostridium difficile. A panel of four antisera, obtained by immunizing rabbits with washed whole cells of different strains of C. difficile, produced distinctive patterns of agglutination. Ethylenediaminetetraacetate (EDTA) extracts subjected to PAGE also produced distinctive protein profiles. Excellent correlation between the two methods was observed when geographically distant isolates were typed without knowledge of their clinical origin. Both typing methods should receive further evaluation for their value as tools for epidemiological studies.

Agglutination Tests↗
PubMed1986

Ciprofloxacin, azlocillin, ceftizoxime and amikacin alone and in combination against gram-negative bacilli in an infected chamber model.

Ciprofloxacin, azlocillin, ceftizoxime, and amikacin were studied alone and in combination against six Enterobacteriaceae and six strains of Pseudomonas aeruginosa in an infected chamber model in rabbits simulating a closed space infection. In-vivo results were compared with in-vitro tests of inhibition, killing and synergy. Ciprofloxacin was the most effective single agent, with efficacy against five of the six Enterobacteriaceae when used in low doses, and two of the six pseudomonads when used in high doses. The development of in-vitro resistance to ciprofloxacin was observed during therapy in strains which failed to be eradicated. Ciprofloxacin and azlocillin together was the most effective regimen, with efficacy against eleven of the twelve strains. Synergy, as determined by chequerboard testing, did not correlate with in-vivo outcome. Unlike mezlocillin, azlocillin, ceftizoxime or amikacin, MIC testing of ciprofloxacin was predictive of in-vivo success.

Amikacin↗
PubMed1986

Ketoconazole and flucytosine alone and in combination against Candida spp. in a neutropenic site in rabbits.

Ketoconazole and flucytosine were administered alone and in combination for ten days to rabbits with four candida isolates growing in subcutaneously implanted semipermeable chambers. The peak concentrations of ketoconazole in serum and in the chamber were 20.3 and 3.8 mg/l, respectively, and the concentrations of flucytosine 47.7 and 37.3 mg/l, respectively. The two drugs combined resulted in better fungistatic activity than either drug alone against all four isolates. Correlation of efficacy in the rabbit model with in-vitro MICs was good for flucytosine, but poor for ketoconazole.

Animals↗
PubMed1986

Hospital distribution, persistence, and reintroduction of related gentamicin R plasmids.

A single plasmid clone was predominantly responsible for gentamicin resistance at the Minneapolis Veterans Administration Medical Center (MVAMC) for 9 years, although two unrelated R plasmids were found. Epidemiological data and restriction endonuclease analysis of 25 plasmid isolates suggested that the clonally derived plasmid population had persisted at the hospital. However, one case of reintroduction of the original epidemic plasmid from a hospital in another state was documented 4 years after the introduction of the original plasmid to the MVAMC. Resistance by the clonally derived plasmid population was not localized geographically within the MVAMC but rather was a hospital-wide problem. Furthermore, previously described classes of DNA rearrangement of the original plasmid were also widely disseminated in the hospital, implying that spread of strains bearing index-related plasmids was relatively unimpeded within the MVAMC despite extensive barrier isolation and cohorting measures. Potential environmental reservoirs of the plasmids were identified in hospital sinks and drains, but their relation to continued patient infection is not known.

Conjugation, Genetic↗
PubMed1986

Frequency of aminoglycoside 6'-N-acetyltransferase among Serratia species during increased use of amikacin in the hospital.

The incidence of tobramycin-resistant, gentamicin-susceptible Serratia species at the Minneapolis Veterans Administration Medical Center decreased from an average 42.1 to 2.5% (P less than 0.001) during a 4.5-year period despite the predominant use of amikacin. These organisms were shown to express a 6'-N-acetyltransferase-modifying enzyme (EC 2.3.1.82). Resistance was not shown to be plasmid mediated.

Acetyltransferases↗
PubMed1986

Treatment of pulmonary sporotrichosis.

Pulmonary infection with Sporothrix schenckii is extremely rare. The small number of reported cases and lack of comparative clinical trials make assessment of treatment regimens difficult. Three modalities should be considered: Saturated solution of potassium iodide (SSKI), amphotericin B, and resective surgery. Available data suggest that SSKI is unlikely to be successful in cavitary disease or disease in immunocompromised hosts. Amphotericin B alone has been successfully used to cure cavitary pulmonary sporotrichosis, but overall cure rates probably are no higher than 50%, and the probability of cure in bilateral apical disease is dismal. Surgical resection has been successful when used alone in a small number of cases. The highest cure rates (70% to 80%) appear to be a result of management with amphotericin B or SSKI combined with resective pulmonary surgery. The dosage and duration of amphotericin B or SSKI to be used in conjunction with surgical resection is unknown.

Humans↗
PubMed1986

Clostridium difficile-associated diarrhea and colitis in adults. A prospective case-controlled epidemiologic study.

In a one-year period, 149 adult cases of Clostridium difficile-associated diarrhea and colitis were compared with 148 diarrhea-free controls. Eighty-seven percent were nosocomial and 75% were on surgical services. Endoscopy revealed pseudomembranes in 51% of the 109 cases in which stool cytotoxin was present, compared with 11% of the 40 cases that were culture-positive but cytotoxin-negative. Cases diagnosed only by stool culture showed essentially no differences from controls, 21% of whom had asymptomatic stool colonization. We estimate that only 20% of these cases had diarrhea due to C difficile. Compared with controls, cases diagnosed by the presence of cytotoxin or pseudomembranes were found to have been hospitalized longer at diarrhea onset, to have had more antecedent infections, and to have received clindamycin, multiple antimicrobials, and therapeutic antimicrobials more often than controls, but controls received prophylactic antimicrobials more frequently than cases. Cultures of the environment, patients, and personnel failed to detect a mechanism of acquisition.

Adult↗
PubMed1985

Aminoglycoside resistance in gram-negative bacilli during increased amikacin use. Comparison of experience in 14 United States hospitals with experience in the Minneapolis Veterans Administration Medical Center.

Resistance to amikacin, gentamicin, and tobramycin was surveyed prospectively during controlled aminoglycoside usage in 14 hospitals. Following an initial baseline period (minimum, three months) during which gentamicin use predominated, gentamicin and tobramycin were placed on restrictive control, establishing amikacin as the aminoglycoside of general use (86 percent of total aminoglycoside usage). During an average of 35 months' restriction of gentamicin and tobramycin, significant reductions in gram-negative resistance to gentamicin (8.4 to 7.0 percent, p less than 0.001) and tobramycin (6.0 to 5.3 percent, p less than 0.01) were observed. The most significant decreases in resistance to gentamicin and tobramycin (p less than 0.001) were found for Pseudomonas aeruginosa, Klebsiella species, Serratia species, and Proteus species. Amikacin resistance among gram-negative bacilli was observed to increase marginally from 1.4 to 1.7 percent (p less than 0.05) during the surveillance period, primarily due to a significant increase in resistance among P. aeruginosa (3.0 to 3.9 percent, p = 0.05). These data were compared with data from a similar surveillance program at the 700-bed Minneapolis Veterans Administration Medical Center. Over a period of 54 months, both gentamicin and tobramycin resistance decreased significantly when amikacin was used (p less than 0.001), then increased with reintroduction of gentamicin (p less than 0.05), and decreased significantly with reintroduction of amikacin (p less than 0.001). Despite predominant amikacin use for a total of 38 months, amikacin resistance did not increase and actually decreased significantly (p less than 0.05) in the last 12 months.

Amikacin↗
PubMed1985

Clinical and endoscopic findings in patients early in the course of clostridium difficile-associated pseudomembranous colitis.

Endoscopic and clinical features are reported for 39 patients detected early in the course of pseudomembranous colitis. Disease was detected early by virtue of careful surveillance in patients in whom diarrhea developed. Early proctosigmoidoscopic findings in pseudomembranous colitis are illustrated. Clinical presentation includes development of fever, leukocytosis, abdominal pain, and even an ileus picture on radiography in addition to diarrhea.

Adult↗
PubMed1985

Acceptance of hepatitis B vaccine by hospital personnel.

Personnel at high risk of acquiring hepatitis B in two university-affiliated teaching hospitals were offered immunization against this disease. Of the 1,193 employees, 454 (38%) requested immunization. Individuals who declined or deferred immunization were sent questionnaires requesting the reasons for their decisions. Responses to the questionnaire were received from 487 of 674 personnel (72%). Most respondents (greater than 90%) indicated that they: 1) were aware of being at risk of acquiring hepatitis B, and 2) recognized the potential danger of the disease. A majority of respondents (56%) indicated that they had decided not to be immunized because they wanted to wait until more was known about the vaccine. Concern about specific side effects (eg, Guillain-Barré syndrome or acquired immunodeficiency syndrome) was cited much less often as a reason for declining immunization. Nearly one-fifth of questionnaire respondents either did not know the date of their last tetanus-diphtheria immunization or had not received a booster within the past decade.

Attitude to Health↗
PubMed1985

Relation between in vivo abscess localization and in vitro migration and adherence of neutrophils.

Rabbit peripheral blood and glycogen-stimulated peritoneal neutrophils were labeled with [111In]indium oxine and transfused intravenously into recipient rabbits with experimental abdominal abscesses due to Staphylococcus aureus. Peritoneal neutrophils harvested 4 hr after glycogen infusion localized within the abscesses to a greater extent than did peripheral blood neutrophils (P less than .002). In an in vitro chemotaxis under-agarose assay, peripheral blood neutrophils had greater random migration (P less than .002) and directed migration (P less than .01) than did peritoneal cells. In an in vitro glass slide adherence assay, peritoneal neutrophils were more adherent than were blood neutrophils (P less than .05). The discrepancy between in vivo and in vitro findings may be due to the increased adherence of peritoneal neutrophils. Glycogen-stimulated peritoneal neutrophils have been exposed in vivo to C5a, which is known to decrease migration and increase adherence in vitro of polymorphonuclear neutrophils; consequently, in vivo exposure of neutrophils to C5a may mean in vitro migration data may be misleading in predicting results in vivo.

Abscess↗
PubMed1985

Mezlocillin, ceftizoxime, and amikacin alone and in combination against six Enterobacteriaceae in a neutropenic site in rabbits.

Closed-space, locally neutropaenic infection sites were simulated in rabbits by implanting subcutaneous semipermeable chambers inoculated with 5 X 10(4) cfu/ml of Escherichia coli (one strain), Citrobacter diversus (one strain), Klebsiella pneumoniae (two strains) or Serratia marcescens (two strains). Four hours after inoculation, treatment was begun with amikacin (15 mg/kg), mezlocillin (100 mg/kg), or ceftizoxime (50 mg/kg) alone or in two-drug combinations. Antibiotics were given intramuscularly every 6 h for 16 doses. Chambers were sampled for bacterial counts at the start of therapy, and 20, 44, and 92 h thereafter. Blood and chamber antibiotic levels were determined during the treatment course. In-vivo results were compared to in-vitro tests of inhibition, killing and synergism. Ceftizoxime alone was successful in vivo (greater than 6 log reduction in count) against the three strains of klebsiella and citrobacter, mezlocillin against one serratia strain, and amikacin alone against none of the strains. The best in-vitro correlation was with the minimum inhibitory concentration (MIC) at a high (10(8] inoculum for the beta-lactams and with the anaerobic MIC for amikacin. Among combinations, amikacin plus mezlocillin alone was successful against the three strains of klebsiella and serratia, but neither amikacin nor mezlocillin added to ceftizoxime were more successful than ceftizoxime alone. In-vitro chequerboard synergism was not predictive of in-vivo success. Mezlocillin alone was inactivated in vivo by all the strains except Ser. marcescens, and the E. coli strain inactivated both mezlocillin and ceftizoxime alone and in combination.

Agranulocytosis↗
PubMed1985

In vitro activity of ciprofloxacin combined with azlocillin.

A ciprofloxacin plus azlocillin broth microdilution checkerboard was evaluated against 125 aerobic gram-negative and gram-positive bacteria. Synergism (sigma FIC less than or equal to 0.5) occurred among 56% of Pseudomonas aeruginosa, 30% of Acinetobacter species, and 40% of Staphylococcus aureus studied. Antagonism (sigma FIC greater than or equal to 2) was present in less than 1% of the organisms.

Anti-Bacterial Agents↗
PubMed1985

Microdilution aminoglycoside susceptibility testing of Pseudomonas aeruginosa and Escherichia coli: correlation between MICs of clinical isolates and quality control organisms.

The monthly variation in geometric mean MICs (GMICs) of amikacin, tobramycin, and gentamicin for Escherichia coli and Pseudomonas aeruginosa laboratory controls and clinical isolates was followed for 30 months. For 19 months, MICs were determined by using Micro-Media system (MMS; Micro-Media Systems, Inc., Potomac, Md.) microdilution panels, and for the other 11 months, MicroScan (MS; American Scientific Products, McGaw Park, Ill.) MIC test panels were used. The aminoglycoside GMICs for control E. coli and P. aeruginosa were significantly lower with the MS system than with the MMS system. A significant correlation was observed between the GMICs for controls and clinical isolates more frequently with the MMS system than with the MS system. Differences are believed to be related to the criteria used in the selection of quality control strains.

Amikacin↗
PubMed1984

Plasmid macroevolution in a nosocomial environment: demonstration of a persistent molecular polymorphism and construction of a cladistic phylogeny on the basis of restriction data.

Descendants of a gentamicin resistance plasmid first isolated from the Minneapolis Veterans Administration Hospital in 1975 persisted at the hospital until 1983. During this extended period of time several macroevolutionary variants arose and two classes of variants were shown to persist with the initial plasmid. It was possible to construct a cladistic phylogeny on the basis of restriction endonuclease cleavage patterns of the initial and variant plasmids. Additionally, a plasmid polymorphism comprised of members of the plasmid classes was shown to persist at the hospital throughout the endemic period.

Cross Infection↗