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Biomedical subjects

T Makin

Publications and source records attributed to T Makin.

At least 19 recordsLinked to original sources
PubMed1995

Control of Legionella pneumophila in a hospital water system by chlorine dioxide.

Immuno-compromised patients are particularly susceptible to Legionnaires' Disease. After three cases of the disease occurred in a hospital, a continuous dosing regime using chlorine dioxide was initiated to replace chlorination of the water system. This study identified a number of factors which may have resulted in conditions that would encourage the growth of the water-borne pathogen Legionella pneumophila. The residual chlorination was inadequate for microbial control at the taps furthest from the four storage tanks, of which two were found to be in excess for demand. The temperature of the water in the storage tanks was also found to be above 20 degrees C; a temperature that would encourage microbial growth. A back-up calorifier was present and was found to contain L. pneumophila, and linseed oil-based sealants that provide nutrients for microbial growth were also prevalent as jointing compounds in the water circuit. Although the shower heads were routinely disinfected, a requirement was identified to also disinfect the shower hoses. No L. pneumophila were recovered from the water system after the chlorine reduced dioxide disinfection trial. Biofilm was also dramatically reduced after disinfection; however, small microcolonies were identified and proved to be metabolically active when tested with a metabolic indicator. Using light and fluorescence microscopy, the pipe samples removed from the water system were rapidly analysed for biofouling, complementing existing microbiological methods.

Chlorine↗
PubMed1991

Legionella in hospitals: a review.

Although epidemics of nosocomial Legionnaires' disease attract great attention, up to 30% of sporadic cases of hospital-acquired pneumonia are caused by legionellae. Legionellae are ubiquitous contaminants of potable water and can achieve high numbers in the hot-water systems of large buildings such as hospitals. They are present in the mains water supply in small numbers but are amplified considerably in the hospital's hot-water system. This is encouraged by water temperatures below 50 degrees C, areas of stagnation and sludge formation, the presence of amoebae and other bacteria and the materials used in the piping. Formation of aerosols from contaminated water is a major mode of spread of legionellae, but there is evidence to suggest that aspiration is also a mode of entry. Safe levels of legionellae in cooling towers have been defined, but not for hot-water systems. A combination of culture and antigen detection by immunofluorescence offer the best method for enumerating legionellae in environmental samples. Control involves a mixture of physical (heat, UV irradiation, sanitation) and chemical (hypochlorite, ozone) methods combined with good plumbing practice (e.g. arrangement of pumps and calorifiers, elimination of dead-legs). Adequate control can be costly and requires considerable attention to detail.

Air Conditioning↗
PubMed1991

The effect of a self-regulating trace heating element on Legionella within a shower.

A self-regulating trace heating element was assessed for its ability to maintain a temperature of 50 degrees C in the mixer valve and dead-legs of a shower, and for its effect on legionellas colonizing the shower. The trace heating element maintained a temperature of 50 degrees C +/- 1.5 degrees C in dead-legs when the circulating hot water supply remained above 45 degrees C. Legionellas appeared in a trace heated dead-leg when the temperature of the dead-leg reached 45 degrees C and the hot water supply dropped below this temperature. Legionellas were eradicated or significantly reduced in sections of the shower where a temperature of 50 degrees C was consistently achieved. The mixer valve which was trace heated but not insulated remained colonized with Legionellas. Legionellas were found in shower water throughout the study.

Equipment Contamination↗
PubMed1990

The efficacy of control measures for eradicating legionellae in showers.

The efficacy of secondary control measures on showers colonized with legionellae was assessed. Hyperchlorination of shower heads and angle valve strainers had only a short-lived effect on legionellae. Automatic drain valves fitted to showers were ineffective in maintaining a reduction in the number of legionellae in shower water. Regular flushing of showers reduced legionellae to below detectable levels. Removal of dead-legs from the feed-pipes supplying hot water to showers, resulted in a decrease in legionellae in these sites but an increase in legionellae colonizing mixer valve components.

Baths↗
PubMed1989

Legionella pneumophila serogroup 12 pneumonia in a renal transplant recipient: case report and environmental observations.

We describe the first reported case of pneumonia due to Legionella pneumophila serogroup 12 in the UK. This hospital-associated infection occurred in an immuno-incompetent patient and coincided with a change in character of the local environmental strains of legionellas. The patient produced a serological response both to her own isolate and to L. pneumophila serogroups 1-6. Thus serodiagnosis was attainable using the usual screening antigens.

Adult↗
PubMed1989

Detection of Legionella pneumophila in environmental water samples using a fluorescein conjugated monoclonal antibody.

Sixty-three environmental water samples from various sources were examined for the presence of Legionella pneumophila with a commercially available direct fluorescent monoclonal antibody (GS), an indirect fluorescent antibody test (IFAT) and culture. GS detected L. pneumophila in 94% and 100% of environmental water samples which were culture and IFAT positive for L. pneumophila, respectively. IFAT detected 69% of L. pneumophila culture positive samples. Cultures of L. pneumophila serogroups 1 to 12, 14 and non-L. pneumophila bacteria which may be found in water, and bacteria containing non-specific binding proteins, were stained by GS and IFAT. GS identified all serogroups of L. pneumophila and did not cross react with any non-L. pneumophila bacteria. L. pneumophila in environmental samples was easy to detect against a clear dark background when stained with GS.

Antibodies, Bacterial↗
PubMed1988

Amoxycillin-clavulanic acid (Augmentin) antibiotic prophylaxis against wound infections in renal failure patients.

A randomized, controlled trial of the use of amoxycillin with clavulanic acid (Augmentin) for prophylaxis against wound infections following major surgery, including transplantation, in patients with chronic renal failure, was undertaken. Six of 22 control patients developed wound infections (27%) whereas no patient in the treatment group (24) developed a wound infection (P less than 0.05). After the termination of this trial, the next 35 consecutive patients received prophylactic amoxycillin/clavulanate; of these only two developed wound infections associated with leakage from their pancreatic anastomoses. All the wound infections were shown to be caused by bacteria sensitive to amoxycillin/clavulanate. Pharmacokinetic studies in patients have shown that a bactericidal concentration of the drugs was present for up to 20 h post-operatively in patients on dialysis, and in recipients of non-functioning renal transplants. In patients with normal renal transplant function excretion of the drug within 12 h was observed.

Adult↗
PubMed1987

Evaluation of the skin disinfecting activity and cumulative effect of chlorhexidine and triclosan handwash preparations on hands artificially contaminated with Serratia marcescens.

The initial and cumulative efficacy of two antiseptic handwash preparations in eliminating Serratia marcescens from hands was evaluated on volunteers. Two antiseptics with persistent skin antibacterial activity, 4% chlorhexidine gluconate in detergent and 1.5% triclosan in natural soap, were studied in a new protocol designed according to Food and Drug Administration guidelines. After a single handwash, both preparations exhibited a degerming action statistically superior to the mechanical elimination of the marker organism that was achieved by the nonmedicated controls. Following a further nine hand recontamination sequence with 10(9) colony-forming units (cfu)/mL S marcescens (mean predisinfection baseline, log10 6.6), the efficacy of chlorhexidine and triclosan was significantly augmented: the mean log10 reduction factors were 4.15 and 3.78, respectively. In the absence of internationally accepted testing standards for antiseptic handwash products, the significance of protocol variables is discussed. The advantages to preventative microbiology of antiseptics with persistent skin antibacterial activity are highlighted.

Chlorhexidine↗
PubMed1987

Comparative evaluation of the immediate and sustained antibacterial action of two regimens, based on triclosan- and chlorhexidine-containing handwash preparations, on volunteers.

The degerming effect of a 3 min handwash with 2% triclosan, or 4% chlorhexidine, in detergent and enhanced efficacy of either antiseptic in isopropyl alcohol, was evaluated in volunteers. Handwashing with either antiseptic preparation reduced the normal flora by a factor of 10; alcohol rubbing by approximately a factor of 1000. Both regimens eliminated Micrococcus roseus, artificially inoculated before every procedure. The sustained action of the same detergent preparations was further studied in gloved and ungloved hands by the Vinson's 'finger imprint test'. In the gloved hand both antiseptics inhibited Staphylococcus epidermidis for 4 h. In the ungloved hand however, triclosan remained active longer than chlorhexidine. Whilst the activity of chlorhexidine was short-lived against a clinical isolate of S. aureus, particularly in the ungloved hand, the sustained effect of triclosan against the same strain persisted for 4 h on either hand.

Bacteria↗
PubMed1983

Intestinal changes associated with rotavirus and enterotoxigenic Escherichia coli infection in calves.

Newborn calves inoculated with rotavirus, enterotoxigenic Escherichia coli (ETEC) serotype 020:K' x 106':K99:HNM, either alone or in combination, became depressed, anorectic, diarrhoeic and dehydrated. ETEC did not adhere to the intestine although there was extensive proliferation in the lumen. Only slight mucosal changes were induced by ETEC and the activity of membrane bound lactase remained normal. More severe mucosal damage and a decrease in lactase activity were found in newborn calves inoculated with either rotavirus or rotavirus and ETEC in combination. The most severe clinical illness was found in calves inoculated with both rotavirus and ETEC. Calves inoculated at 1 week of age with either rotavirus or ETEC remained clinically normal. Rotavirus infection produced slight mucosal changes and a reduction of lactase activity. In contrast, colostrum-fed or suckling calves up to 2 weeks old inoculated with both rotavirus and ETEC became clinically affected, showed severe mucosal damage and decreased lactase activity. There was no bacterial adhesion to the intestinal mucosa as observed by immunofluorescent labelling and light microscopy.

Animals↗
PubMed1983

Assessment of the remanent antibacterial effect of a 2% triclosan-detergent preparation on the skin.

A method of quantifying the remanent antibacterial effect of a 2% triclosan preparation in detergent following three consecutive applications on the forearm of 20 volunteers over 2 h, is described with reference to its efficacy against a gentamicin- and multiply-resistant serotype of Klebsiella aerogenes. The relevance of the residual activity of triclosan and other skin antiseptics in surgical and hygienic hand disinfection are discussed.

Detergents↗
PubMed1982

Enterocolitis in piglets caused by Cryptosporidium sp. purified from calf faeces.

Twelve gnotobiotic piglets were dosed with a bacteria-free calf faecal homogenate which contained Cryptosporidium oocysts. The infection induced severe enterocolitis in piglets when inoculated at 1 day of age, moderate diarrhoea at 7 days of age and a subclinical infection at 15 days of age. In piglets aged 3 days or less, the entire intestine was extensively infected with Cryptosporidium and the mucosa was severely damaged. In piglets 7 days of age or older, the upper small intestine was sparsely infected with the organisms, but the ileum and the large bowel were heavily infected with associated mucosal damage.

Aging↗
PubMed1982

Enteritis in foals induced by rotavirus and enterotoxigenic Escherichia coli.

Colostrum-deprived, colostrum-fed or suckling foals were orally inoculated with foal rotavirus and enterotoxigenic Escherichia coli derived from a calf. Neither agent given alone caused diarrhoea in foals aged 1 or 2 days, although with rotavirus, 2 of the 3 inoculated foals became depressed 3 days after inoculation and all 3 were excreting rotavirus in the faeces. Inoculation of both agents induced diarrhoea in colostrum-deprived, colostrum-fed or suckling foals aged up to 16 days. There was an apparent age-related resistance to diarrhoea which developed between 2 and 3 weeks of age. It was related to failure of rotavirus to establish apparent infection in older foals and was independent of preinoculation maternal antibody.

Animals↗
PubMed1982

Experimental colibacillosis in gnotobiotic piglets exposed to 3 enterotoxigenic serotypes.

Three strains of enterotoxigenic Escherichia coli (ETEC) (064:KSNT, K88ac; 020:KSNT, K88ac and 08:K85ab, K99) originally cultured from outbreaks of diarrhoea in piglets a few hours old, were administered orally to gnotobiotic piglets. There was a marked age-related difference in the clinical response to infection between the 3 strains although they all produced heat-stable toxin. All 3 strains produced severe clinical signs of depression, anorexia, vomiting, diarrhoea, followed by dehydration and death in one-day-old piglets. In piglets infected at 3 days of age the two K88+ ETEC caused diarrhoea and death but the K99+ ETEC induced moderate diarrhoea only. In piglets infected at 7 days of age, the 064 strain produced severe diarrhoea and death, and 020 strain caused mild diarrhoea in 3 of 6 piglets with one death while the 08 strain caused no illness. Pathological changes in the intestinal tract associated with these infections were minimal, or absent. Immunofluorescent staining with homologous hyperimmune sera demonstrated adherence of the 3 ETEC strains to the brush border of small intestinal epithelial cells. Fluorescing organisms were observed in all infected piglets irrespective of the severity of clinical signs but the degree and extent of colonisation varied with the age of the piglets and the infecting strain. This may explain the difference in clinical response between the 3 strains.

Animals↗