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Biomedical subjects

R Hone

Publications and source records attributed to R Hone.

At least 37 records · Page 2Linked to original sources
PubMed1989

Enterotoxin production by Staphylococcus aureus isolates from cases of septicaemia and from healthy carriers.

In a prospective study, 52 Staphylococcus aureus isolates from individual patients with septicaemia and 27 nasal strains from separate, healthy carriers were compared for production of a range of extracellular proteins and toxins. Whereas there was no difference (p greater than 0.05) between septicaemic and nasal isolates with respect to incidence of alpha, beta, gamma and delta haemolysins, toxic shock syndrome toxin-1 or staphylokinase production, the incidence of enterotoxin A, B, and C production was higher among isolates from septicaemia (p less than 0.01). Of the isolates from septicaemia, 33 (63%) produced enterotoxins A, B, C or D alone or in combination. Only three (11%) of the nasal isolates produced a single enterotoxin, enterotoxin D. Of the isolates from septicaemia, 67% were hospital-acquired and greater than 25% of these were endemic, methicillin-resistant (MRSA) strains. All MRSA strains produced either enterotoxin A, or enterotoxin B, or both. These findings suggest a possible role for enterotoxins in the pathogenesis of S. aureus disease other than food poisoning.

Bacterial Toxins↗
PubMed1988

Sources and outcome for methicillin-resistant Staphylococcus aureus bacteraemia.

Eighty-eight episodes of MRSA septicaemia occurring in 82 patients were studied prospectively. In 15 episodes bacteraemia was transient, in 36 non-fatal, in 33 fatal, while in four septicaemia was a major contributory factor in the patient's death. There were more patients aged over 60 years in the septicaemia groups compared to the transient bacteraemia group (P = 0.01), and patients with septicaemia were usually recently postoperative and/or suffering from severe underlying disease. Circulation access sites were the commonest source of the bacteraemic organisms with non-surgical wounds including burns, varicose ulcers and bed sores as the next most common. In four of the 16 burns patients, fatal septicaemia followed surgical debridement of infected burns. In only eight episodes was there no apparent source of bacteraemia.

Adolescent↗
PubMed1987

To tunnel or not to tunnel catheters for parenteral nutrition.

The effect of subcutaneous catheter tunnelling on the incidence of catheter sepsis and on catheter life span in the absence of a nutrition team was determined in a prospective controlled clinical trial. Eighty one patients who received 92 courses of parenteral nutrition had 110 catheters inserted. Alternate catheters were tunnelled. Four patients who received parentheral nutrition for less than 48 hours were excluded from the study. Catheter related sepsis occurred in one tunnelled (1.8%) and 4 non-tunnelled catheters (7.6%) (P greater than 0.05 NS). Mean life span of tunnelled catheters was 21 days (range 5-37 days) compared to 12.6 days for non-tunnelled (range 3-19 days) (P less than 0.05). Six non-tunnelled catheters became displaced, a complication which did not occur with tunnelled catheters (P less than 0.01). In conclusion subcutaneous tunnelling of silicone catheters prolongs catheter life span but does not significantly influence catheter sepsis.

Bacterial Infections↗
PubMed1985

Methicillin-resistant Staphylococcus aureus in Dublin 1971-84.

Between 1971 and 1975, methicillin-resistant Staphylococcus aureus (MRSA) caused sporadic infection in eight Dublin hospitals although a case of bacteraemia was not recorded until 1976. From then on gentamicin-resistant MRSA rapidly became endemic in Dublin hospitals. The frequency of MRSA bacteraemia reached a peak in 1979-82 but MRSA infection remains an important problem. The most effective antimicrobial agent in treatment of invasive infection was vancomycin; little drug toxicity was seen. Where appropriate, concomitant surgical treatment such as debridement and drainage was usually necessary. Infection control measures directed at eliminating carriage proved effective in reducing spread. Molecular analysis showed two distinct MRSA phenotypes with similar phage-typing patterns. Gentamicin resistance was chromosomally encoded.

Gentamicins↗
PubMed1985

Susceptibility to antimicrobial agents and analysis of plasmids in gentamicin- and methicillin-resistant Staphylococcus aureus from Dublin hospitals.

Methicillin- and gentamicin-resistant Staphylococcus aureus (MGRSA) strains isolated from Dublin Hospitals were classified into two groups (phenotypes). Phenotype-I strains expressed high level resistance to gentamicin and were susceptible to fusidic acid; strains resistant to tetracycline harboured a 3 X 10(6)-mol. wt plasmid. Strains in phenotype II usually expressed low level resistance to gentamicin, were resistant to fusidic acid and often harboured a (22-24) X 10(6)-mol. wt plasmid that specified resistance to ethidium bromide, tetracycline, kanamycin, neomycin and trimethoprim, or to combinations of these markers. A few phenotype-II strains expressed higher levels of resistance to gentamicin and other aminoglycosides. All MGRSA strains carried a 21 X 10(6)-mol. wt plasmid conferring resistance to penicillin, ethidium bromide, cadmium and mercury. Gentamicin resistance was invariably chromosomal and all strains carried chromosomal resistance to methicillin, erythromycin, streptomycin and spectinomycin. Several methicillin-resistant S. aureus (MRSA) strains isolated before the emergence of gentamicin resistance harboured a 21 X 10(6)-mol. wt penicillinase plasmid with the same restriction endonuclease profile as that from some MGRSA strains. Some MRSA strains carried other plasmids related to those found in MGRSA strains.

Anti-Bacterial Agents↗
PubMed1985

Antimicrobial chemotherapy of septicemia due to methicillin-resistant Staphylococcus aureus.

The outcome of treatment of 48 episodes of septicemia due to methicillin-resistant Staphylococcus aureus (MRSA) in 44 patients was assessed. Twenty-six of the patients died; nineteen of them died of infection, and infection was a major contributing factor to the deaths of the remaining seven patients. Fourteen of fifteen patients treated with inadequate antibiotic therapy died, and the other patient developed a mycotic aneurysm of the femoral artery, for which amputation was necessary. Eight of eleven patients treated with amikacin (alone or combined with another antimicrobial) died, and three recovered slowly; only one recovered fully without sequelae. In an additional two patients who failed to respond to amikacin, treatment was changed to vancomycin. Vancomycin was used to treat 18 episodes of MRSA septicemia in 17 patients. In 14 of these episodes the patients recovered fully. One patient died of uncontrolled infection, and in three, infection was a contributing factor but not the major cause of death. Vancomycin was confirmed as antibiotic of choice in treating MRSA septicemia.

Adult↗
PubMed1984

Clinical experience with aztreonam in urinary and respiratory tract infections.

Twenty patients with severe infection, 10 of the urinary tract and the other 10 of the respiratory tract, were enrolled in a clinical trial of aztreonam, a new monobactam antimicrobial agent. For the urinary tract infections, the mean duration of treatment was 7 days, with doses ranging from 0.25 to 1.0 g aztreonam intravenously twice daily. Sustained clinical and microbiological cure was achieved in 9 of the 10 patients. In the group with respiratory infections, the mean duration of treatment was 9.3 days, patients receiving 1 g aztreonam intravenously 3-times daily. Initial clinical cure was achieved in 9 of the patients, the tenth showing an incomplete response. However, bacteriological recurrence, related to the persistent nature of the underlying disease, occurred in 6 of the 10 patients during the 1-month follow-up period. The only side-effects were mild, transient biochemical abnormalities which did not require drug withdrawal in any patient.

Adult↗
PubMed1983

Gentamicin and methicillin resistant Staphylococcus aureus in Dublin hospitals: clinical and laboratory studies.

Strains of Staphylococcus aureus resistant to gentamicin and methicillin first appeared in Dublin hospitals in 1976, and rapidly became widely disseminated. The number of patients infected or colonised increased throughout the period of study, especially in 1979 and 1980. Most isolates were from burns, surgical wounds and traumatic skin lesions. During the 12 months after first isolation of these multiply antibiotic resistant strains, colonisation or minor infection was the usual event. Invasive infection such as bacteraemia, deep wound sepsis and osteomyelitis was rarely seen. Subsequently, as the number of patients from whom these organisms were isolated increased, bacteraemia and other severe infection became more common. The predominant phage type of S. aureus changed with the progression of the outbreak. Isolates of different phage type were sometimes found in a single lesion, or in different sites in one patient. By the second half of 1980, most isolates were untypable or typed only with an experimental phage.

Bacteriophage Typing↗