Inorganic particulate matter modulates non-typeable Haemophilus influenzae growth: a link between chronic bacterial infection and geogenic particles.

Australian Aboriginal populations have unacceptably high rates of bronchiectasis. This disease burden is associated with high rates of detection of pathogenic bacteria, particularly non-typeable Haemophilus influenzae (NTHi). While there is evidence to suggest that exposure to inorganic particulate matter (PM) is associated with worse respiratory infections, no studies have considered the direct effect of this PM on bacterial growth. Nine clinical isolates of pathogenic NTHi were used for this study. Isolates were exposed to two common iron oxides, haematite (Fe2O3) or magnetite (Fe3O4), or quartz (SiO2), as the main constituents of environmental inorganic PM. NTHi isolates were exposed to PM with varying levels of heme to identify whether the response to PM was altered by iron availability. The maximal rate of growth and maximum supported growth were assessed. We observed that inorganic PM was able to modify the maximal growth of selected NTHi isolates. Magnetite and quartz were able to increase maximal growth, while haematite could both increase and suppress the maximal growth. However, these effects varied depending on iron availability and on the bacterial isolate. Our data suggest that inorganic PM may directly alter the growth of pathogenic NTHi. This observation may partly explain the link between exposure to high levels of crustal PM and chronic bacterial infection in Australian Aboriginals.

Antimicrobial susceptibility testing of cystic fibrosis and non-cystic fibrosis clinical isolates of Pseudomonas aeruginosa: a comparison of three methods.

Pseudomonas aeruginosa is an important pathogen in humans, particularly in the context of nosocomial infection and infections of the cystic fibrosis (CF) lung. In order to provide clinicians with information about the likely effectiveness of specific antimicrobial treatment for P. aeruginosa infections, clinical laboratories employ in vitro antimicrobial susceptibility testing. Two commonly employed methods are the CLSI disc-diffusion and Etest methods. The purpose of this study is to compare the accuracy of susceptibility results generated by these two methods against agar dilution as the reference method. Susceptible or nonsusceptible (resistant and intermediate) results of the Etest and CLSI disc-diffusion methods are compared with CLSI agar dilution results for a large cohort of clinical cystic fibrosis (n = 71) and non-cystic fibrosis (n = 83) isolates using CLSI interpretive criteria. An unacceptable number of major and very major errors were observed for various antimicrobials tested against both CF and non-CF isolates when using the Etest and CLSI disc-diffusion methods. The potential for error in standard laboratory antimicrobial susceptibility testing should be considered by clinicians when being guided by the results of such tests in the prescription of antimicrobial agents for P. aeruginosa infection.

Maternal and neonatal sepsis caused by Haemophilus influenzae type d.

A 29-year-old pregnant woman was admitted to hospital with signs of sepsis and threatened pre-term labour. The premature neonate also showed signs of sepsis. Haemophilus influenzae biotype III was cultured from a midstream urine sample taken from the mother, maternal placental swabs and neonatal blood cultures. The placental and neonatal isolates were both found to be serotype d by PCR, and were indistinguishable by PFGE.

Caffeine ingestion during exercise to exhaustion in elite distance runners. Revision.

Caffeine is currently being used as an ergogenic aid by many athletes. The aim of this research was to determine whether a large dose of caffeine (10 mg.kg-1) taken immediately prior to the start of endurance exercise would have the desired effect of increasing endurance performance. Six males, who were not habitual caffeine users and who had performed at least two marathons, served as subjects in this experiment. They ran on a treadmill at a speed which had been calculated would elicit 75% of their VO2max for 45 minutes, after which time the speed was increased by two miles per hour till exhaustion. During the caffeine trial the athletes ran further than either the control or placebo conditions (p less than 0.05). Blood lactate values did not change across condition except for the final collection period which was significantly higher in the caffeine trial (p less than 0.05). As expected there was a significant time effect in all conditions (p less than 0.0001). Blood triglycerides after the start of the test were always higher in the caffeine condition but this was only significant at the 45 minute and end of exercise collection periods (p less than 0.05). The results suggest that endurance athletes can use caffeine just prior to exercise rather than one to three hours prior to exercise.

Wound infection following high saphenous ligation. A trial comparing two skin closure techniques: subcuticular polyglycolic acid and interrupted monofilament nylon mattress sutures.

A prospective, randomized trial was performed to compare the incidence of wound infection following skin closure with subcuticular polyglycolic acid and interrupted monofilament nylon mattress sutures in patients undergoing high saphenous ligation (126 patients; 75 polyglycolic acid wounds, 86 interrupted monofilament nylon mattress wounds). By 6 weeks after operation, pus had discharged from 15 (20%) polyglycolic acid wounds compared with seven (8%) interrupted monofilament nylon mattress wounds (P = 0.05), giving an overall infection rate of 13.7%. Infection occurred in 23% of the 56 procedures performed by the two surgeons with the highest infection rates compared with 8% of the 105 procedures performed by the remaining nine surgeons (P = 0.02). The excess of infections in wounds closed with subcuticular polyglycolic acid was caused by an excess of infections in operations performed by the two surgeons with the highest infection rates. The higher infection rate found with subcuticular polyglycolic acid appeared to be operator dependent.

Caffeine ingestion prior to incremental cycling to exhaustion in recreational cyclists.

Nine male recreational cyclist served as subjects in this experiment which included a control, placebo and caffeine trial. The aim of the experiment was to determine whether a 10 mg.kg-1 dose of caffeine given three hours prior to an incremental cycle ergometer exercise test, for caffeine naive subjects, would increase the time to exhaustion and therefore increase the amount of work undertaken by the cyclists. The cyclists initially worked at 100 watts for three minutes and then increased the workload by 50 watts every three minutes until exhaustion. Blood was drawn at the beginning of the test and every three minutes from an ante-cubital vein and was analysed for blood lactate, glucose and free fatty acids (FFA). Respiratory analysis was also undertaken and heart rate was monitored throughout the test. Subjects in the caffeine trial worked significantly longer and performed more work (p less than 0.05) than they did in either the control or placebo trials. FFA's were also significantly higher in this trial (p less than 0.05) and the lactate threshold was moved to the right as a percentage of the VO2max, which suggests less acidity and a decreased bicarbonate flushing. The respiratory exchange ratio data was significantly lowered (p less than 0.05) during workloads between 250 and 450 watts. No changes were seen in blood glucose or heart rates during the experiment. In conclusion, we feel that a 10 mg.kg-1 dose of caffeine is an ergogenic aid during incremental exercise when it is taken 3-4 hours prior to the exercise in fasting subjects who have diets low in caffeine.

Phosphate loading and the effects on VO2max in trained cyclists.

It is known that an increased level of red blood cell 2,3-diphosphoglycerate (DPG) shifts the oxyhemoglobin dissociation curve to the right, thus allowing a greater unloading of oxygen at the tissue level. It has been hypothesized that phosphate might help increase VO2max by increasing 2,3-DPG level. Eight trained cyclists underwent three cycle ergometer tests (control, placebo, and experimental) to determine whether phosphate ingestion had any positive effect on VO2max, time to exhaustion, serum 2,3-DPG, and serum phosphate levels. We found no change between the control, placebo, or experimental conditions in pretest serum phosphate levels, but we did find increases in 2,3-DPG levels in the phosphate condition (p less than .05), which suggests that even a small amount of phosphate could increase levels of 2,3-DPG. We also found significant differences in VO2max between the control (p less than .05) and placebo (p less than .02) conditions and also in time to exhaustion between the three conditions (p less than .05). We suggest that phosphate may have an ergogenic effect, but clearly more work needs to be undertaken to ascertain the amount of phosphate required and the magnitude of the effect.

First record of human acanthocephalan infections in Australia.

Two cases of asymptomatic acanthocephalan infections in infants are described. We believe this is the first report from Australia of infection with these parasites in humans. Their clinical, epidemiological and biological significance is discussed.

A comparison of oral astemizole with topical sodium cromoglycate in the treatment of hay fever.

An open, parallel group study was carried out in 95 hay fever patients during the 1984 season to compare the efficacy of oral astemizole with that of topical sodium cromoglycate. Patients were allocated at random to receive astemizole once daily (30 mg during the first week, then 10 mg for the rest of the study period) or sodium cromoglycate (2%), administered 6-times daily intranasally and 4-times daily in the eyes, for a maximum of 8 weeks. The severity of patients' nasal and ocular symptoms was assessed daily on two separate 100 mm visual analogue scales throughout the study period. No statistically significant difference could be detected between the two treatment groups in the control of either nasal or ocular symptoms. Side-effects in both groups were minor and transient. It is suggested that astemizole, however, has the advantage of greater patient convenience and cost effectiveness in hay fever sufferers.