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C T Keane

Publications and source records attributed to C T Keane.

At least 55 records · Page 3Linked to original sources
PubMed1994

Pre-formed urease activity of Helicobacter pylori as determined by a viable cell count technique--clinical implications.

The pre-formed urease activity of three NCTC reference strains and five clinical isolates of Helicobacter pylori was determined at room temperature (21 degrees C) and 37 degrees C by a viable cell count technique with a conventional urea slope test (Christensen's agar) as well as the commercial CLO-test. The urease activity of two gastroduodenal commensals, Proteus mirabilis and Klebsiella pneumoniae, was also tested. H. pylori strains produced positive reactions with viable cell counts of 10(6)-10(8) cfu within 30 min and with counts of 10(3)-10(6) cfu within 2 h. For some strains, smaller numbers of organisms were needed with the CLO-test than with the conventional test, and incubation of the CLO-test strips at 37 degrees C slightly decreased the number of organisms required for positive results. P. mirabilis produced a positive result on urea slopes with an initial inoculum of 10(7)-10(8) cfu at 2 h, but no positive reaction occurred for K. pneumoniae at 12 h, even with an initial inoculum of 10(11) cfu. However, both P. mirabilis and K. pneumoniae gave a positive result after incubation for 24 h with initial inocula of < 10(1) cfu and 10(3)-10(4) cfu respectively. Incubation at 37 degrees C significantly reduced the inoculum size of these organisms required for a positive result after incubation for 4 h when tested with the slopes, but not with the CLO-test. These findings indicate that H. pylori possesses much greater pre-formed urease activity than P. mirabilis and K. pneumoniae. False negative results for clinical detection of H. pylori in gastroduodenal biopsies may be due to small numbers of organisms, especially after treatment with antimicrobial agents, and false positive results may arise from gastroduodenal commensals or contaminants.

Colony Count, Microbial↗
PubMed1994

Antibiogram-resistogram typing scheme for methicillin-resistant Staphylococcus aureus.

An antibiogram-resistogram (AR) typing scheme that can simply and rapidly differentiate methicillin-resistant Staphylococcus aureus (MRSA) isolates has been devised. Susceptibility to antibiotics and chemicals was determined by disk diffusion testing. Three disk diffusion methods and three control S. aureus strains were evaluated. A modified Stokes' technique in which S. aureus ATCC 25923 replaced S. aureus NCTC 6571 as the control organism was chosen. Susceptibility patterns against 18 antibiotics and four chemicals were used to determine AR types. AR subtypes were determined with reference to knowledge of the local MRSA population so that plasmid loss would not result in misclassification. AR typing was compared with phage typing and plasmid profiling and found to be more discriminatory than either of these typing methods. Representative isolates of the most frequently occurring AR patterns were further characterised by investigating enterotoxin production, MICs of gentamicin and amikacin, and restriction endonuclease analysis of plasma DNA, to determine whether apparently different strains could have the same AR pattern and to devise confirmatory tests for any such similar patterns. One pattern was shared by two strains but isolates could be differentiated by susceptibility to minocycline. This typing scheme can be used in the diagnostic laboratory and results may be obtained within 24 h.

Anti-Bacterial Agents↗
PubMed1994

Evaluation of an antibiogram-resistogram typing scheme for methicillin-resistant Staphylococcus aureus.

Between Dec. 1992 and Aug. 1993, the MRSA population in the Federated Dublin Voluntary Hospitals and St James's Hospital group was studied with an antibiogram-resistogram (AR) typing scheme in which AR patterns were determined by testing susceptibility to 22 antibiotics and chemicals by a modified Stokes' disk diffusion technique. The typing scheme divided this MRSA population into 31 AR types but 90% of isolates belonged to seven types. Isolates belonging to the most frequently occurring types (AR types 13 and 14) differed only in their reaction to lincomycin (or clindamycin) and could not be distinguished by phage typing, plasmid profiling or restriction endonuclease analysis. The AR typing scheme showed that the incidence of different AR types varied in different hospitals and changed during the study period. This typing method differentiated a strain of MRSA responsible for a nosocomial outbreak in an intensive care unit from other MRSA isolated in the unit, and has distinguished imported strains from local ones. In one hospital, AR typing showed that, although a major outbreak occurred with one AR type, there was also a series of smaller outbreaks with other AR types. The technique can be performed in the diagnostic laboratory and results were available within 24 h.

Anti-Bacterial Agents↗
PubMed1994

Small intestinal bacterial overgrowth--an incidental finding?

OBJECTIVES: To assess the prevalence of typical clinical features and need for treatment of small intestinal bacterial overgrowth (SIBO) in the elderly. DESIGN: Random selection of patients, regardless of their nutritional status. SETTING: Acute admissions ward in the Dept. of Medicine for the Elderly. PATIENTS: Thirty elderly patients between 68 and 90 years of age. MEASUREMENTS: Active clinical problems, including the presence of recent weight loss and diarrhea, were recorded. Routine blood tests, including serum vitamin B12, red cell folate, albumin and calcium, and qualitative small bowel bacteriology results, were analyzed. The effect of age on all variables was studied. RESULTS: Twenty of the 30 small bowel aspirates had proven SIBO, and strict anaerobes were isolated in 15. The mean blood test values did not differ significantly between culture-positive and culture-negative patients. There was no significant correlation between those variables and the total bacterial counts. Of the 20 proven SIBO cases, eight had anemia, five had hypoalbuminemia, five had diarrhea, four complained of recent weight loss, and none had B12 deficiency. Alternative causes other than SIBO were identified for many of these abnormalities. Advancing age correlated significantly with rising counts of small bowel strict anaerobes. CONCLUSIONS: These data suggest that age may be a predisposing factor in the development of anaerobic overgrowth but that SIBO is a benign entity in the elderly. Contrary to previous recommendations, treatment of this condition is not routinely indicated.

Age Factors↗
PubMed1994

Standardization of disk diffusion test and its clinical significance for susceptibility testing of metronidazole against Helicobacter pylori.

Susceptibilities of 121 clinical Helicobacter pylori strains to metronidazole were determined by both a 5-micrograms metronidazole disk diffusion test and a plate dilution method in duplicate and after different periods of incubation. The distribution of MICs of metronidazole against H. pylori among the strains was found to be bimodal. The diameters of inhibitory zones obtained by the disk diffusion test and the MICs obtained by the plate dilution method correlated well, especially after 4 days of incubation (r = 0.77). An inhibitory zone diameter of 20 mm was found to correspond to a MIC of 8 micrograms/ml and is recommended as a suitable zone for differentiating susceptibility and resistance with a 5-micrograms metronidazole disk. Three interpretive categories of susceptibility results were defined; strains with inhibitory zone diameters of more than 26 mm were defined as susceptible (MIC, < 4 micrograms/ml), strains with zone diameters of 20 to 26 mm were deemed intermediate (MIC, 4 to 8 micrograms/ml), and those with zone diameters of less than 20 mm were deemed resistant (MIC, > 8 micrograms/ml). Furthermore, 76 H. pylori-positive patients with duodenal ulcers or nonulcer dyspepsia were treated with a 1 week of triple therapy (colloidal bismuth subcitrate, metronidazole, and tetracycline). H. pylori strains were isolated before treatment from antral biopsies from those patients, and the metronidazole susceptibilities of the strains were determined by the disk diffusion test. H. pylori status was evaluated again 4 weeks after completion of treatment. The eradication rates for susceptible, intermediate, and resistant strains were 95.9% (47 of 49), 62.5% (5 of 8), and 52.6% (10 of 19), respectively. It is included that the 5-micrograms disk diffusion test is easy to perform and gives final results similar to those of the plate dilution method. The three interpretive categories of susceptibility may be of benefit for clinical choice of chemotherapy in eradicating H. pylori.

Adolescent↗
PubMed1994

Transportation of Helicobacter pylori cultures by optimal systems.

Cultures of Helicobacter pylori on chocolate agar slants in bijou bottles and on chocolate agar plates inside BBL Campy Pouches were mailed from Dublin to Galway, Ireland; Bordeaux, France; and Beijing, China. Both systems maintained viability of H. pylori for at least 4 days under mailing conditions. Ninety percent of the isolates on the slants survived for 6 days, but only 30% of the isolates in the pouches survived. When the slants were stored at 4 degrees C after arrival, 50% of the isolates were recoverable 10 days after mailing. Failure of recovery was due to coccoid formation by the organisms. Contamination was not a problem in either system. Chocolate agar slants are considered the more suitable system for transporting H. pylori cultures, especially when transport time longer than 4 days is expected.

Agar↗
PubMed1993

Prevalence of metronidazole-resistant Helicobacter pylori in dyspeptic patients.

Susceptibility to metronidazole of 213 clinical strains of H. pylori from dyspeptic patients was determined by a plate dilution method. Seventy two (33.8%) of the strains were resistant to metronidazole (MIC > 8 mg/L), 20 of these were from 24 patients who had received previously metronidazole (83.3%), giving a primary (pretreatment) resistance rate of 27.5% (52/189). The resistance rate was higher in women than in men, especially aged 50 to 59 years old (43.6% vs 23.3%, p < 0.001). The resistance rate was lower in patients at 60 or over (9.8%), but similar between the younger patients groups (38.8% - 49.0%). There was no difference in the resistance rate between peptic ulcer disease (32.6%) and nonulcer dyspepsia (34.7%). These data indicated that metronidazole resistance in H. pylori is absolutely associated with previous use of the drug, and the higher resistance rate in women may be due to the more frequent prescription of the drug for their gynaecological infection or operation. Therefore, testing of susceptibility of H. pylori to metronidazole is important. A new susceptibility testing technique, the E-test was evaluated in this study and found to give comparable results to the plate dilution method and also had the advantage of being simple to perform.

Adolescent↗
PubMed1993

Determination of the optimal transport system for Helicobacter pylori cultures.

A range of solid and liquid media was evaluated for the ability to maintain survival of Helicobacter pylori strains under different conditions. Chocolate agar slopes maintained survival of most strains for longer than 3 days, some strains surviving for up to 9 days, despite a decreased number of viable cells. Temperature and atmosphere did not significantly influence the performance of these slopes. The BBL Campy Pouch system also achieved a considerable recovery rate of H. pylori after storage for 3 days at the same range of temperatures. Brain-heart infusion broth with horse serum was superior among the liquid media tested, maintaining the viability of H. pylori for c. 3 days at temperatures ranging from -4 degrees C to 21 degrees C. Chocolate agar slopes are recommended as suitable for transport of H. pylori strains.

Culture Media↗
PubMed1993

Enhanced cultivation of Helicobacter pylori in liquid media.

AIMS: To evaluate a technique for culture of Helicobacter pylori in large quantities of liquid media and to determine the factors that could influence the results. METHODS: Fifteen clinical isolates of H pylori and a reference strain of H pylori NCTC11637 were used to evaluate a method to cultivate the organism in 100 ml liquid medium comprising brain heart infusion broth with 5% horse serum and 0.25% yeast extract. Tissue culture flasks containing the inoculated liquid medium were placed in a CO2 incubator with 5% CO2 for 2 hours and then incubated in a shaking incubator at 120 rpm. RESULTS: All the clinical isolates and the reference strain grew in the broth, although only a moderate growth of the reference strain occurred. Inoculum size significantly influenced the kinetics of growth of H pylori in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B, used to suppress contamination, did not affect growth of H pylori in the medium. CO2 was essential for H pylori to grow or survive in the liquid medium. Incubation with CO2 in a CO2 incubator for 30 minutes or 2 hours did not affect the results. CONCLUSIONS: H pylori can be cultivated in large quantities of brain heart infusion broth with 5% horse serum and 0.25% yeast extract. Initial inoculum concentrations influence the kinetics of H pylori growth in the liquid medium. Vancomycin, nalidixic acid, and amphotericin B can be used as selective antimicrobial agents. CO2 is essential for initial growth of H pylori in liquid media. The findings in this study may provide a useful, reproducible, and simple method for biochemical, molecular, and physiological studies of H pylori, when those require large quantities of the organism.

Amphotericin B↗
PubMed1992

Application and assessment of cloacin typing of Enterobacter cloacae.

Three methods, O-serotyping, phage typing and susceptibility to bacteriocins, were used to type 357 clinical isolates of Enterobacter cloacae cultured from 219 patients. One hundred and sixty isolates were typed by serology and phage typing. When these two methods were used, primary classification of isolates was based on serology (65.7% typable) and phage typing for further subdivision (94.1% typable). When all the isolates were typed by cloacin susceptibility, 81.5% of them were typable. Maximum discrimination between cultures was achieved when the three methods were used together; no single method was sufficiently discriminatory. There was a close parallel between serotyping and bacteriocin lysis pattern. The latter was easy to perform and the results were achieved within 48 h. By applying this typing system two episodes of cross-infection were identified in a haematology/oncology unit and intensive care unit.

Bacteriophage Typing↗
PubMed1991

The effect of bile acids on the growth and adherence of Helicobacter pylori.

Bile reflux gastritis occurs in the absence of Helicobacter pylori (H. pylori). The aim of this study was to see if the bile acids cheno or ursodeoxycholic acid affected the growth or adherence of H. pylori in vitro. Twenty-seven strains growth were inhibited by 0.1% chenodeoxycholic acid whereas only 11 out of the 27 were inhibited by 0.1% ursodeoxycholic acid. Growth was totally inhibited by a combination of 0.05% chenodeoxycholic acid +0.05% ursodeoxycholic acid. Chenodeoxycholic acid was a more effective inhibitor of adherence in that the number inhibited and percentage inhibition were greater than with ursodeoxycholic acid. Bile salts might be useful in the treatment of H. pylori infection.

Animals↗
PubMed1990

Importation of methicillin-resistant Staphylococcus aureus from Baghdad to Dublin and subsequent nosocomial spread.

We report the spread of a methicillin- and gentamicin-resistant Staphylococcus aureus strain (MGRSA) from the Middle East and its subsequent dissemination within two hospitals in Dublin. The index case, a 30-year-old male with serious blast injuries was transferred from a Baghdad hospital to a Dublin hospital in May 1985. He was heavily infected with two MGRSA strains, one of which spread and was responsible for numerous episodes of nosocomial infection. This strain was very similar to MGRSA isolates recovered in a Baghdad hospital during 1984. This imported strain has now spread to two hospitals in our group causing sepsis. This report emphasizes the difficulty of detecting an imported strain in an endemic area, but above all points to the potential for spread when there is considerable movement of patients and personnel.

Adult↗
PubMed1990

Effects of an enteric anaerobic bacterial culture supernatant and deoxycholate on intestinal calcium absorption and disaccharidase activity.

Fifty two strains of anaerobic bacteria isolated from the upper gut of patients with small intestinal bacterial overgrowth were screened for phospholipase activity. Bacteroides melaninogenicus spp intermedius had the greatest activity. The effects of culture supernatants of this organism and deoxycholate on intestinal calcium absorption and disaccharidase activity were studied using a rat closed loop model. The supernatant decreased the in vitro uptake of calcium by 15% (p less than 0.001). Deoxycholate reduced calcium uptake by 16% (p less than 0.001). Combined culture supernatant and deoxycholate reduced calcium uptake by 39% (p less than 0.001) suggesting a potentiation of supernatant activity by deoxycholate. Culture supernatant and deoxycholate, both alone and combined, significantly reduced lactase, sucrase, and maltase activity. Electron microscopic evidence showed degeneration of microvilli, disruption of mitochondrial structure, and swelling of the endoplasmic reticulum after exposure of the intestinal loops to the supernatant or deoxycholate.

Animals↗
PubMed1990

Coagulase testing compared with commercial kits for routinely identifying Staphylococcus aureus.

Five commercial Staphylococcus aureus identification kits--Staphaurex (Wellcome), Staphylase (Oxoid), Staphyslide (bioMèrieux), Biostaph (Medlabs) and Bacto Latex (Difco)--were evaluated for the routine identification of S aureus from primary plates in the routine microbiology laboratory. Comparison was made with two methods of tube coagulase testing and five slide methods for detecting clumping factor (slide coagulase testing). Performances were assessed for two groups of organisms, staphylococcal species alone and a combined staphylococcal and non-staphylococcal species group. The effects of growth on selective media and storage of isolates at room temperature and 4 degrees C were investigated. Selective media cannot be recommended, nor can storage of isolates before testing. Ranked according to efficiency value with the combined staphylococcal and non-staphylococcal species group, the kits and coagulase methods performed as follows (the figures in parentheses are the efficiency values for the staphylococcal group alone): tube coagulase reference method 100% (100%), tube coagulase SJH method 99% (99%), Staphaurex 94% (97%), Staphylase 93% (96%), slide coagulase method No 4 93% (94%), slide coagulase method No 5 93% (93%), Bacto Latex 92% (95%), Staphyslide 92% (95%), and Biostaph 87% (91%). It is concluded that a commercial S aureus identification kit should not replace tube coagulase testing for the routine identification of the organism from primary plates and that, even the kits with the best performances, have little advantage over a good slide coagulase test method.

Bacteriological Techniques↗
PubMed1990

Cryptococcal meningitis occurring in HIV infected individuals.

Three cases of cryptococcal meningitis in patients with HIV infection are described. A high index of suspicion is required for diagnosis. India ink preparation and culture of the CSF for cryptococcus is mandatory in HIV seropositive patients irrespective of the CSF white cell count and biochemistry.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Nebulized amphotericin B as prophylaxis against invasive aspergillosis in granulocytopenic patients.

The efficacy of inhaled amphotericin B in prevention of invasive aspergillosis in patients with granulocytopenia (granulocytes less than 0.5 X 10(9)/l for greater than 10 days) was investigated over a 12-month period. Amphotericin B prophylaxis was administered twice daily for the period of granulocytopenia to 34 patients who were at risk during 144 episodes of granulocytopenia. The cohort at risk was compared with historical controls. In the 2 years prior to institution of prophylaxis, 14 patients (11.4% of those at risk) developed invasive aspergillosis. All cases occurred whilst the patients were nursed on the open wards. Aspergillosis did not develop in 25 granulocytopenic patients nursed in single rooms with HEPA filtration. Since institution of prophylaxis, there have been no cases of invasive aspergillosis. These data suggest that nebulized amphotericin B may be useful in preventing invasive pulmonary aspergillosis in granulocytopenic patients, especially those nursed on the open wards, and warrants further investigation.

Agranulocytosis↗