Molecular systematics of Campylobacter isolated from the human clinical environment.

Campylobacter jejuni is the major cause of campylobacteriosis in humans. This thesis recorded the distribution of C. jejuni and C. coli isolates in a hospital environment during 1997/98. 105 clinical isolates of Campylobacter were examined using flaA and gmhA PCR-RFLP analysis. Isolates were collected from 84 patients who presented at Christchurch Public Hospital or from the South Canterbury region. Males accounted for 63.1 % of the sample. The largest number of cases was reported in the age group 20-29 years. flaA specific primers were applied to all samples with 83.8 % generating a 1.7 kb amplicon. RFLP analysis using DdeI provided 17 different flaA profiles, with flaA 6 being the most common type identified in this study. 82.9 % of the sample generated a distinguishable profile. This technique provided a D value of 92 % (D = Simpson's index of diversity). gmhA primers were also applied to this sample, with 71.4 % generating either a 900 bp, 1.6 kb or multiple band profile. 62.9 % of the sample provided a distinguishable RFLP profile. gmhA 1 was the most commonly observed profile. This technique provided a D value of 74 %. When combining these two genetic markers, discrimination was increased. 59 % (n=62) of the isolates had provided both flaA and gmhA profiles. These isolates were distributed into 22 different classifications. MLEE analysis was applied to the largest flaA group in an attempt to further assess relationships. This analysis allowed flaA 6 to be subdivided into a further five groups, therefore increasing strain discrimination. PCR-RFLP procedures were highly reproducible, robust, discriminative and rapid to perform. However 17.1 % and 37.1 % were untypeable by flaA and gmhA respectively. 20 environmental (sheep) isolates from Massey University were also examined using flaA and gmhA PCR-RFLP analysis. Four flaA types and two gmhA types were observed amongst these isolates. The flaA and gmhA types had been previously observed in the clinical isolates, therefore suggesting that no strain was specific to a particular environment. However not all isolates were typeable with these two methods

Pharmacokinetics and antibacterial activity of daily gentamicin.

Twenty full term neonates with suspected bacterial infection were randomly assigned to a once daily or a twice daily dosage regimen with gentamicin (4 mg/kg/day). Concomitantly all patients were treated with ampicillin (200 mg/kg/day). The gentamicin concentration time curves were analysed by an open two compartment model under steady state conditions on day 4 of treatment. The mean theoretical maximum serum concentration in the group taking gentamicin once daily (10.9 micrograms/ml) was significantly higher than in the group taking it twice daily (7.4 micrograms/ml). Potentially toxic serum concentrations were never reached. Mean trough concentrations were comparable in both groups (once daily 0.8 micrograms/ml; twice daily 1.0 micrograms/ml). Urinary alanine aminopeptidase excretion increased during and even two days after end of treatment in both groups without any significant differences. The results of the dynamic in vitro model revealed that both dosage schedules showed comparable bactericidal effects on pathogens inhibited by low concentrations of gentamicin like Escherichia coli and Staphylococcus aureus. However the once daily regimen was significantly superior in isolates with high minimal inhibitory concentrations