Does single application of topical chloramphenicol to high risk sutured wounds reduce incidence of wound infection after minor surgery? Prospective randomised placebo controlled double blind trial

OBJECTIVE

To determine the effectiveness of a single application of topical chloramphenicol ointment in preventing wound infection after minor dermatological surgery.

DESIGN

Prospective randomised placebo controlled double blind multicentre trial.

SETTING

Primary care in a regional centre in Queensland, Australia.

PARTICIPANTS

972 minor surgery patients.

INTERVENTIONS

A single topical dose of chloramphenicol (n=488) or paraffin ointment (n=484; placebo).

MAIN OUTCOME MEASURE

Incidence of infection.

RESULTS

The incidence of infection in the chloramphenicol group (6.6%; 95% confidence interval 4.9 to 8.8) was significantly lower than that in the control group (11.0%; 7.9 to 15.1) (P=0.010). The absolute reduction in infection rate was 4.4%, the relative reduction was 40%, and the relative risk of wound infection in the control group was 1.7 (95% confidence interval 1.1 to 2.5) times higher than in the intervention group. The number needed to treat was 22.8.

CONCLUSION

Application of a single dose of topical chloramphenicol to high risk sutured wounds after minor surgery produces a moderate absolute reduction in infection rate that is statistically but not clinically significant. Trial registration Current Controlled Trials ISRCTN73223053.

Louse (Insecta: Phthiraptera) mitochondrial 12S rRNA secondary structure is highly variable

Lice are ectoparasitic insects hosted by birds and mammals. Mitochondrial 12S rRNA sequences obtained from lice show considerable length variation and are very difficult to align. We show that the louse 12S rRNA domain III secondary structure displays considerable variation compared to other insects, in both the shape and number of stems and loops. Phylogenetic trees constructed from tree edit distances between louse 12S rRNA structures do not closely resemble trees constructed from sequence data, suggesting that at least some of this structural variation has arisen independently in different louse lineages. Taken together with previous work on mitochondrial gene order and elevated rates of substitution in louse mitochondrial sequences, the structural variation in louse 12S rRNA confirms the highly distinctive nature of molecular evolution in these insects.

Human cryptosporidiosis in North Queensland

During a 12-month period, feces from 780 persons from the Townsville region were evaluated by the Kinyoun acid-fast strain, and 36 (4.6%) immunocompetent patients were found to have Cryptosporidium oocysts. Twenty-five index cases were identified; 13 (8.6%) cases from 151 patients were from Palm Island, an isolated Aboriginal community in the wet tropics and 12 (1.9%) cases from 629 patients were from the dry tropics of Townsville. All 11 secondary cases were associated with a person-to-person outbreak in the nursery of a Townsville day-care centre. Infection occurred mainly in two distinct age groups: the under five-year-old (27 cases), and the 25 to 35-year-old (six cases). A prodrome of dry cough, rhinorrhea and vomiting often preceded symptoms of fever, weight loss, abdominal pain, persistent cough and vomiting, and acute diarrhea with frequent, non-bloodstained, watery, mucous stools. Although 13 patients were hospitalised because of their illness, the infection was self-limiting and all 36 patients recovered with symptomatic treatment. Cryptosporidium was the third most commonly identified enteric pathogen after Rotavirus and Giardia. Infection did not appear to depend on seasonal variation and no animal or environmental sources of infection were identified. Cryptosporidiosis in immunocompetent persons is endemic and common in North Queensland and routine investigations for this parasite in symptomatic patients are warranted.