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Biomedical subjects

J M Hamilton-Miller

Publications and source records attributed to J M Hamilton-Miller.

At least 91 records · Page 5Linked to original sources
PubMed1992

Cefaclor as a prophylactic agent for recurrent urinary infections: a comparative trial with macrocrystalline nitrofurantoin.

Eighty women with recurrent urinary infections (a median of seven episodes per year) were randomized to twelve months prophylaxis with cefaclor 250 mg or macrocrystalline nitrofurantoin 50 mg, at night. Seventy-three patients (37 given cefaclor and 36 given macrocrystalline nitrofurantoin) were assessable for efficacy. The incidence of radiological abnormalities in the two treatment groups was 23% and 30% respectively. Ninety-five percent of the patients taking cefaclor were symptomatically improved during the twelve months of prophylaxis and 86% remained abacteriuric; corresponding figures in the group taking macrocrystalline nitrofurantoin were 86% and 85% respectively. There were 88 breakthrough infections in patients taking cefaclor (6 resistant strains), and 9 in those patients taking macrocrystalline nitrofurantoin (6 by resistant strains). The mean interval between symptomatic episodes on prophylactic therapy increased by 5.6-fold in patients taking cefaclor, and 4.3-fold in those taking macrocrystalline nitrofurantoin. Resistant coliforms were found in only 3 out of 37 patients studied after twelve months prophylaxis; these organisms did not proceed to cause infections. All 80 patients were assessable for adverse events: 5 out of 39 taking cefaclor (12.8%) reported an event "probably" associated with the antibiotic, and 3 (7.7%) stopped taking the drug for various reasons; corresponding figures for macrocrystalline nitrofurantoin were 17.1% and 9.8% respectively. Patients with a radiological abnormality responded well to long-term low-dose prophylaxis with either agent. Cefaclor seems to offer an alternative to macrocrystalline nitrofurantoin for the prophylaxis of recurrent urinary infections in women.

Adult↗
PubMed1991

Bacteriological safety of cook-chill food at the Royal Free Hospital, with particular reference to Listeria.

Cook-chill food prepared by the Catering Department of the Royal Free Hospital was examined over an 8-month period commencing October 1989. Total aerobic viable counts (TAVCs) were performed on 200 food specimens which were also examined for Listeria using selective enrichment culture. Ten of 200 food samples tested had TAVCs greater than 10(5) colony forming units (cfu) g-1, and nine of these were from non-vegetarian (meat) dishes. Although most of the food prepared by cook-chill had microbial loads within the limits recommended by current Department of Health guidelines (i.e. less than 10(5) cfu g-1), our findings for the non-vegetarian dishes suggest that extra caution is required when preparing such food. Listeria were not isolated from any food sample. In a survey of listeria faecal carriage, Listeria monocytogenes was isolated from only two of 100 faeces specimens obtained from patients.

Colony Count, Microbial↗
PubMed1991

Calculating MIC50.

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Data Collection↗
PubMed1991

Pre-opsonisation of Escherichia coli induces resistance to neutrophil killing in serum and urine: relationship to growth phase.

Tests of phagocytosis and killing by polymorphonuclear neutrophil leucocytes (PMNL) are usually done with pre-opsonised organisms. Phagocytosis of 11 strains of Escherichia coli, pre-opsonised, and in the stationary phase, resulted in the killing of only one strain although all the organisms were phagocytosed. However, when the same strains were added unopsonised to a PMNL-serum mixture, eight were killed after phagocytosis. With two of these strains, the amount of killing was inversely proportional to the time of pre-oposonisation. E. coli incubated for 30 min in dilute peptone water in Hanks's Balanced Salts Solution before phagocytosis also became resistant to killing; bacterial division did not occur during this period. Experiments with bacteria in urine confirmed these findings and showed that E. coli exposed to serum or urine before phagocytosis became resistant to killing by PMNL. E. coli rapidly changes its sensitivity to phagolysosome killing during transition from stationary to lag phase in a nutrient medium. This resistance is retained through the exponential phase but is lost during the stationary phase. The killing of Pseudomonas, Enterobacter, and Acinetobacter by PMNL was unaffected by varying the method of opsonisation or the phase of growth. If this phenomenon occurs in vivo it may affect the outcome of infections caused by strains of E. coli that survive killing by PMNL.

Blood Bactericidal Activity↗
PubMed1991

Differing activities of quinolones against ciprofloxacin-susceptible and ciprofloxacin-resistant, methicillin-resistant Staphylococcus aureus.

The in vitro activities of nine quinolones (seven fluoroquinolones, nalidixic acid, and acrosoxacin) against methicillin-resistant Staphylococcus aureus (MRSA) were compared with those of the glycopeptides teicoplanin and vancomycin. MICs against 160 strains of ciprofloxacin-susceptible (MIC, less than 2.0 micrograms/ml) MRSA and 40 strains of ciprofloxacin-resistant (MIC, greater than or equal to 2.0 micrograms/ml) MRSA were determined. The following MICs for 50% of the strains tested (in micrograms per milliliter) were obtained for ciprofloxacin-susceptible and -resistant strains, respectively: tosufloxacin, 0.06 and 2.0; ofloxacin, 0.25 and 16; ciprofloxacin, 0.5 and 16; pefloxacin, 0.5 and 32; acrosoxacin, 1.0 and greater than 256; enoxacin, 1.0 and 64; fleroxacin, 1.0 and 32; norfloxacin, 2.0 and 64; nalidixic acid, 64 and 512; teicoplanin, 1.0 and 1.0; vancomycin, 2.0 and 2.0. In mutation rate studies using a range of antibiotic concentrations to reflect those achievable in vivo, resistant mutants grew only on plates containing nalidixic acid (rate of mutation to resistance, 10(-7) to 10(-8) and on plates containing low concentrations of ciprofloxacin, enoxacin, and norfloxacin (rate of mutation to resistance, 10(-8) to 10(-9). In time-kill studies, 99.9% killing was found within 8 h for all of the quinolones tested (norfloxacin and nalidixic acid were not tested). Teicoplanin and vancomycin were less rapidly bactericidal. For the clinical isolates of ciprofloxacin-resistant MRSA, different levels and patterns of quinolone resistance were found. Generally, cross-resistance among the fluoroquinolones was complete; however, incomplete cross-resistance did occur with the nonfluorinated quinolone acrosoxacin.

Anti-Bacterial Agents↗
PubMed1991

Comparative trial of norfloxacin and macrocrystalline nitrofurantoin (Macrodantin) in the prophylaxis of recurrent urinary tract infection in women.

Eighty-eight women with a history of recurrent urinary tract infection (at least four attacks in the preceding 12 months) were randomized to take either norfloxacin 200 mg at night (45 patients) or macrocrystalline nitrofurantoin 100 mg at night (43 patients) for 12 months. A decrease in the number of symptomatic attacks while taking this prophylaxis was observed in 94 per cent of the patients and this improvement was maintained during the 6 months following the end of prophylaxis in 69 per cent. The mean interval between symptomatic episodes while taking prophylaxis was 7.2-fold and 6.9-fold greater, respectively, than in the 12 months before starting prophylaxis. There were only nine breakthrough infections during 74 patient-years of prophylaxis, four in patients taking norfloxacin (two enterococci, one Staphylococcus epidermidis, one Escherichia coli), and five in those taking macrocrystalline nitrofurantoin (four E. coli, one Klebsiella pneumoniae). Adverse events caused four patients taking norfloxacin (8 per cent) and seven taking macrocrystalline nitrofurantoin (14 per cent) to stop prophylaxis. Norfloxacin had a marked suppressive effect on the coliform part of the faecal flora, with no emergence of resistance. Thus, norfloxacin appears to be an excellent alternative agent to macrocrystalline nitrofurantoin for the prevention of recurrent urinary infections.

Adolescent↗
PubMed1991

Comparative in vitro activity of cefixime, cefaclor and loracarbef against urinary pathogens.

Minimum inhibitory concentrations of cefixime, cefaclor and loracarbef have been determined against 200 strains of bacteria, representing a wide selection of species causing urinary infections. Cefixime was poorly active against Gram-positive species, but was active (MIC90 less than 2 mg/l) against almost all the Gram-negative pathogens tested (except Pseudomonas aeruginosa), and particularly so against Klebsiella pneumoniae and members of the tribe Proteae. Cefaclor and loracarbef were more active against the Gram-positive species than was cefixime, but had a less broad spectrum against the Gram-negative species. Cefixime use seems more appropriate in nosocomial than in domiciliary urinary infections.

Anti-Infective Agents, Urinary↗
PubMed1990

Urinary infection in the 1990's: the state of the art.

Growing points and problem areas in the field of urinary tract infections are critically surveyed. It is concluded that there is a particular need for advances in rapid tests for bacteriuria (to distinguish between symptomatic patients who are infected and those who are not) and for the determination of antibiotic sensitivity of infecting organisms. The aetiology of the "urethral syndrome" (dysuria and/or frequency without a significant bacteriuria) is still obscure although it is becoming clear what suggested possible causes are not responsible for it. Another unresolved problem is whether or not to treat asymptomatic bacteriuria in all groups of patients especially the elderly, and in the absence of pyuria. Similarly it is still not decided what are the optimal lengths of time and dosages of antibiotics to treat various types of urinary infections. Finally, difficulties involved in preventing infections of in-dwelling catheters, and the possibility of obtaining a protective vaccine are discussed.

Anti-Infective Agents, Urinary↗
PubMed1990

The emergence of antibiotic resistance: myths and facts in clinical practice.

Selection pressure, caused by the use of antibiotics--especially in hospitals--is the main factor responsible for the emergence of antibiotic-resistant bacteria. Resistance can arise endogenously by mutation (one-step, as found for Mycobacterium tuberculosis to rifampicin, or multi-step, as in gonococci to benzylpenicillin), or exogenously by transfer of R-factors. Mechanisms of resistance may involve a decrease in permeability, chemical modification of the antibiotic, or a change in the affinity of the target site. There are many misconceptions concerning the incidence, nature and spread of antibiotic resistance, and some of the most important of these are discussed. The emergence and spread of resistance can be controlled by adhering to antibiotic policies and by preventing or controlling outbreaks of infection. The importance of resistant organisms can be diminished by the development of new antibiotic agents, preferably containing new chemical entities.

Anti-Bacterial Agents↗
PubMed1990

Haemophilus influenzae and H. parainfluenzae as urinary pathogens.

Two cases are described, one of Haemophilus influenzae urinary infection in a female with no past history of urinary tract infection (UTI) and the other of Haemophilus parainfluenzae infection in a male with a renal calculus. Haemophilus spp. are rare urinary pathogens and these cases are even more unusual because H. influenzae UTI has almost always previously been found in either children or adult males, while H. parainfluenzae UTI has only been reported once before.

Aged↗
PubMed1990

Detective work in continuous ambulatory peritoneal dialysis.

We report five cases of continuous ambulatory peritoneal dialysis in which the mechanisms and sources of infection were established. We show how diligent enquiry and environmental investigation can explain the pathogenesis of infection and help in prevention by motivation of the patient.

Aeromonas↗