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Biomedical subjects

B I Davies

Publications and source records attributed to B I Davies.

At least 19 recordsLinked to original sources
PubMed1999

A Streptococcus pyogenes outbreak caused by an unusual serotype of low virulence: the value of typing techniques in outbreak investigations.

OBJECTIVES: To investigate and stop the spread of an outbreak of Streptococcus pyogenes infection in a district general hospital, involving 19 patients and two nurses over a 20-day period. METHODS: All suspected persons were investigated using conventional bacteriological techniques, followed by M, T and exotoxin gene-typing of the isolates in a national reference laboratory. RESULTS: 11 patients and both nurses were associated with the acute surgical ward on one floor of the hospital. They were infected with serotype M 9/T B3264, a strain with apparently low virulence, which has not been previously associated with outbreaks. Two other patients on the same floor each had different types and there were two clusters of another S. pyogenes serotype on other floors, each involving two patients. Two (unrelated) patients yielded other types of S. pyogenes. The patients were not seriously ill but had some delay in wound healing. CONCLUSIONS: The value of typing the isolates of S. pyogenes in this outbreak was in defining which patients were involved. No added value could be ascribed to the exotoxin gene-typing results.

Adult↗
PubMed1999

Clinical effectiveness of levofloxacin in patients with acute purulent exacerbations of chronic bronchitis: the relationship with in-vitro activity.

The objective of this randomized, double-blind study was to compare the clinical efficacy of levofloxacin at two different dosages with that of cefuroxime axetil in patients with acute purulent exacerbations of chronic bronchitis and, in particular, to assess the impact of the susceptibility to levofloxacin on the clinical findings. In total, 124 evaluable patients were treated for 7 days with oral levofloxacin 250 mg or 500 mg od, or cefuroxime axetil 250 mg bd. Sputum cultures were monitored pre-treatment, and at 1 and 7 days after the end of treatment. The susceptibility of Streptococcus pneumoniae isolates was tested by agar dilution in Columbia blood agar and by disc diffusion, but all other isolates were tested solely by the disc diffusion method. A greater number of infections were eradicated by levofloxacin than by cefuroxime axetil: infections were eradicated in 68% of patients receiving the 500 mg dosage and in 63% of those taking 250 mg levofloxacin, whereas the eradication rate with the comparator drug was much lower (48%). Against all pre-treatment S. pneumoniae isolates (n = 39), the MICs of levofloxacin were between 0.25 and 2 mg/L (geometric mean 0.95 mg/L), similar to those of the post-treatment strains (n = 32; mean 1.11 mg/L). All except one of the S. pneumoniae isolates were susceptible to penicillin G (MIC < or = 0.06 mg/L), and the remaining isolate was inhibited by 0.5 mg/L of penicillin G, but was fully susceptible to levofloxacin. Some pretreatment strains of Pseudomonas aeruginosa were resistant to levofloxacin, but many more resistant strains were encountered afterwards. All strains of Moraxella catarrhalis and Haemophilus influenzae were highly susceptible to levofloxacin in the disc diffusion tests. All the antimicrobial agents used in the study were well tolerated: only two patients discontinued treatment because of adverse drug effects. The results of this study indicated that, although there were some failures in patients with S. pneumoniae and P. aeruginosa infections, resistance to levofloxacin did not emerge rapidly among strains of S. pneumoniae during therapy with levofloxacin, and that natural resistance among pneumococci, H. influenzae and M. catarrhalis was rare.

Aged↗
PubMed1997

Multicentre in-vitro evaluation of the susceptibility of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis to ciprofloxacin, clarithromycin, co-amoxiclav and sparfloxacin.

Seven laboratories, including a reference laboratory, tested the susceptibility of Moraxella catarrhalis, Streptococcus pneumoniae and Haemophilus influenzae strains to ciprofloxacin, clarithromycin, co-amoxiclav and sparfloxacin with the Etest. A total of 976 strains were collected. The results with ciprofloxacin and sparfloxacin were consistent for all laboratories, while those with clarithromycin and co-amoxiclav were not. The agreement between Etest MICs and broth microdilution was: ciprofloxacin and sparfloxacin, >95%; clarithromycin for all species, 71-85%; co-amoxiclav for H. influenzae, 31%. MIC90 values (broth dilution, mg/L) for M. catarrhalis, S. pneumoniae and H. influenzae were: sparfloxacin, 0.06, 0.5, 0.03; ciprofloxacin, 0.12, 2.0, 0.03; co-amoxiclav, 0.25, 0.25, 0.25; clarithromycin 0.25, 0.25 and 16.

Amoxicillin↗
PubMed1994

Critical review of microbiological data and methods in diagnosis of lower respiratory tract infections.

A review is presented of the microbiological data, and the methods for obtaining these data, which are relevant for the diagnosis of lower respiratory tract infection. The necessity for adequate information exchange between the microbiology laboratory and the clinic is stressed. Once the specimen (usually sputum) has reached the laboratory, it is screened macroscopically and microscopically for adequacy, and cultures are set up. Many patients with acute community-acquired pneumonia (CAP) have no sputum, and some produce purulent sputum containing no obvious infecting micro-organisms. Despite modern microbiological techniques, only 110 out of 250 acute CAP patients had positive bacteriological cultures and 41 more yielded only positive serological results, so that an aetiological diagnosis was reached in 60%. Invasive methods of specimen collection (bronchoscopy, BAL, protected brush, etc) have also been studied, together with quantitative bacterial counting, but the results have not yielded so much useful information that these procedures can be unreservedly recommended. Molecular biological methods (DNA probes, PCR, etc) are only now becoming available. The bacteriological findings in patients with acute CAP have been compared with those in acute exacerbations of chronic bronchitis (CB), and several differences have emerged in the order of frequency of occurence. H. influenzae is in first place with exacerbations of CB, but is second to S. pneumoniae in acute CAP. The latter occupies third position in CB, with Moraxella catarrhalis second. The role of Chlamydia pneumoniae in acute CAP is not yet clear, but the serological results suggest an association in 42 out of 147 patients tested (29%), 15 of whom also had positive bacteriological cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteria↗
PubMed1992

Clinical and bacteriological experience with cefodizime in acute purulent exacerbations of chronic bronchitis.

1 or 2 g doses of cefodizime i.m. were studied in 287 patients admitted to hospital with acute purulent exacerbations of chronic bronchitis, mostly associated with Haemophilus influenzae, Streptococcus pneumoniae or Moraxella catarrhalis. Pharmacokinetic studies in serum and sputum on the first treatment day yielded mean peak serum concentrations of 50 to 100 mg/l, with corresponding sputum concentrations of 1.4 and 2.7 mg/l, after the two respective doses. No great differences were found between the clinical and microbiological results in the various dosage groups, and no corresponding improvement was noted with the highest dosages studied. In general, infection was eliminated in 90 to 95% of patients at the end of treatment, and in approximately 70 to 80% after a follow-up week. Some infections associated with beta-lactamase producing M. catarrhalis persisted or relapsed after treatment. Unwanted drug effects were recorded in five patients, leading to discontinuation in two. It is concluded that a single daily intramuscular dose of 1 g cefodizime for seven days produces satisfactory results in most patients.

Aged↗
PubMed1991

Meningococcal chest infections in a general hospital.

In the course of one calendar year (1989-1990), 46 specimens of respiratory secretions (from 44 patients) cultured in the microbiology department of a large district general hospital in The Netherlands were found to yield Neisseria meningitidis. Twenty-eight of the 46 samples yielded pure cultures of meningococci and 18 yielded other recognised respiratory pathogens as well. Only one patient had pneumonia, whereas 19 had acute respiratory infections and 18 acute purulent exacerbations of chronic bronchitis. The remaining patients, who had a variety of symptoms, all had purulent sputum. Only 8 of the 44 patients were under 40 years of age; 21 were aged more than 60 years. Serological grouping and subtyping showed a predominance of group B strains (in 24 of 44 patients) and 13 strains were non-groupable. The importance of recognising or overlooking meningococci in cultures of respiratory secretions is discussed.

Acute Disease↗
PubMed1990

Cefodizime and cefotaxime in acute exacerbations of chronic bronchitis: a randomized double-blind prospective study in 180 patients.

In a double-blind prospective study, 180 patients admitted to hospital with acute purulent exacerbations of chronic bronchitis were treated for seven days with twice daily 1 g intramuscular injections of either cefodizime or cefotaxime. Sputum cultures performed before, during and immediately after treatment showed complete eradication of the infection in 89/90 given cefodizime and 86/90 receiving cefotaxime. Some symptomatic Pseudomonas aeruginosa superinfections occurred with each agent. During the follow-up week, recurrences or reinfections after apparent clearance occurred in 15 patients given cefodizime and in 21 receiving cefotaxime. Pharmacokinetic studies in blood showed mean Cmax values of 50.8 mg/l for cefodizime and 36.5 mg/l for cefotaxime, corresponding values in the sputum being 1.61 and 0.62 mg/l. Mean AUC values in both blood and sputum were 2 1/2- to 3-fold higher for cefodizime. Some features suggested better performance by cefodizime than by cefotaxime, but the clinical results were not statistically significantly different.

Acute Disease↗
PubMed1990

Temafloxacin in acute purulent exacerbations of chronic bronchitis.

Temafloxacin hydrochloride, a new fluoroquinolone, was given orally in doses of 300 or 600 mg twice daily for ten days to 36 patients, all hospitalized because of severe acute purulent exacerbations of chronic bronchitis. Sputum cultures before, during and after treatment showed that the infection was eliminated in 12/18 evaluable patients given 300 mg and in 13/16 receiving the 600 mg doses. Haemophilus influenzae, Branhamella catarrhalis and Streptococcus pneumoniae were effectively eliminated, but only half the Pseudomonas aeruginosa infections were eradicated. MICs for most pathogens were 1 mg/l or less (including the majority of the pneumococci) but the MICs for Ps. aeruginosa ranged from 0.5 to greater than 16 mg/l, those for 10 of the 22 strains being greater than 2 mg/l. Pharmacokinetic studies on serum and sputum specimens showed serum Cmax values of 3.5 and 6.0 mg/l, the sputum Cmax being 2.35 and 4.17 mg/l after the different doses. No interaction with concomitant theophylline could be found. Two patients complained of moderate nausea or water-brash. Temafloxacin can be considered safe and effective at these dosages, but for Ps. aeruginosa infections higher dosages need to be investigated.

4-Quinolones↗
PubMed1989

Doxycycline and minocycline in the treatment of respiratory infections: a double-blind comparative clinical, microbiological and pharmacokinetic study.

A group of 41 patients, all admitted to hospital because of acute purulent exacerbations of chronic respiratory disease, were treated with either doxycycline or minocycline in a double-blind randomized study. Drug dosage was one 100 mg capsule twice daily for seven days. Bacteriological and clinical assessment before and immediately after treatment showed no significant differences between the doxycycline and the minocycline groups, nor did further evaluation after seven days follow-up. Pharmacokinetic studies showed that the Cmax and 0-11 h AUC values in blood were higher for doxycycline, whereas the sputum Cmax was, on average, higher for minocycline because of the greater penetration of the latter. The MIC values for the two antibiotics differed slightly, usually, but not always, in favour of minocycline. Problems were experienced with both agents in the eradication of Haemophilus influenzae. The net clinical results with the two drugs were identical.

Adult↗