Sequential antibiotic therapy for acne promotes the carriage of resistant staphylococci on the skin of contacts.

The selection of a predominantly resistant staphylococcal skin flora in acne patients during antibiotic treatment has been extensively documented. This study sought to determine whether antibiotic therapy for acne had any effect on skin carriage of resistant coagulase-negative staphylococci (CNS) by close contacts of treated patients. Bacterial samples were obtained using a scrub wash technique from facial skin of 41 contacts (parents, siblings or partners) of patients who had been treated with at least three different antibiotics over a minimum period of 2 years. Samples were also obtained from 41 control subjects who had no known contact with any antibiotic treated acne patient. None of the contacts or controls had received any antibiotic therapy in the preceding two years. The number, percentage and prevalence of CNS resistant to each of seven antibiotics was estimated by plating serial ten-fold dilutions of wash fluid directly onto antibiotic-containing and antibiotic-free medium. Significantly more contacts than controls carried strains resistant to erythromycin, clindamycin, fusidic acid, trimethoprim and chloramphenicol as well as more multiply resistant strains (P < 0.05, chi 2). The number and percentage of staphylococci resistant to tetracycline, erythromycin, clindamycin, fusidic acid and chloramphenicol were also significantly raised (P < 0.05, Mann-Whitney U-test) in contacts. Only aminoglycoside resistance was not increased by any of the above criteria. These observations provide evidence that sequential antibiotic therapy for acne exerts selective pressure for increased skin carriage of resistant CNS not only in patients but also in their close contacts.

Stability of amoxycillin and potassium clavulanate in co-amoxiclav oral suspension.

A study was carried out using high performance liquid chromatography (HPLC) to determine the chemical stability of amoxycillin and potassium clavulanate in 250/62 co-amoxyclav oral suspension (Augmentin), stored at room temperature (RT, 20 degrees C) and 8 degrees C over a period of 11 days. The suspension was judged to be acceptable if its components maintained at least 90% of their label concentrations. During the test period, the amoxycillin component was found to be more stable than the clavulanate. Amoxycillin was stable for 7 days at both temperatures. Potassium clavulanate maintained at least 90% of its initial concentration for 7 days at 8 degrees C but showed more than 40% degradation in the same time period at RT. For potassium clavulate the shelf-life, or time taken for the original concentration to drop to 90% of its value (t90) at RT was found to be 2 days.

Evaluation of the API Coryne system for identification of Listeria species.

The API Coryne system, a commercially available system for the identification of coryneform bacteria, was used to identify 103 strains of Listeria spp. from clinical and environmental sources. All isolates were identified correctly to the genus or species level, although complete characterization also required tests for beta-hemolysis and CAMP reaction.

Food-borne bacterial infections.

The number of episodes of diseases caused by bacterial contamination of food has shown a real increase by about threefold in the last decade in the U.K. The numbers for 1992 are estimated to be 2 million. The causes are multifactorial and complex, and 4 representative pathogens are reviewed. The main increase in diseases due to salmonella has been caused by Salmonella enteritidis, especially from eggs. The commonest bacterial food pathogen is campylobacter, which causes an illness with specific season peaks in May and June. This may be related to the activities of birds and mammals. Both these bacteria cause common diseases that are rarely fatal. In contrast, Listeria and E. coli are ubiquitous but rarely produce disease; however, the consequences of any such illness are often dire. Procedures and techniques are available for the control of most of these diseases, but society does not seem determined to implement them.

Action of povidone-iodine against methicillin-sensitive and -resistant cultures of Staphylococcus aureus.

Forty clinical isolates of methicillin-resistant and methicillin-sensitive Staphylococcus aureus were studied for their susceptibility to povidone-iodine (available iodine 11%) under a variety of conditions. The cultures varied in properties, notably in their sensitivity to other therapeutic agents. No differences were observed between the resistant and sensitive cultures in destruction by povidone-iodine. When bactericidal activity occurred, > 99% of the bacterial cells were lethally damaged within 10 seconds of exposure to povidone-iodine. The bacterial cells that had been washed and resuspended thrice in distilled water were most susceptible, with as little as 1 x 10(-16) G (2.36 x 10(5) atoms) of iodine being required to destroy one bacterial cell. Attempts were made to select variants resistant to iodine from the surviving minority population in such experiments. These experiments failed to select resistance, and it is concluded that any apparent variation in vulnerability to povidone-iodine results from aggregation of the bacteria and differences in penetration of povidone-iodine. Substances were studied for their ability to inactivate povidone-iodine. The most potent agents were the free sulphur-containing amino acids, cysteine and methionine. These are present in high concentrations in nutrient broth and most other culture media. This explains the reports of 'pseudo-resistance' to povidone-iodine in certain laboratory experiments. Suggestions are made for the optimum use and formulation of povidone-iodine.

Evaluation of the Rosco system for the identification of Listeria species.

The Rosco system was used to identify previously confirmed isolates of the seven currently recognised species of Listeria. These included reference cultures and recent isolates from clinical material, food products and environmental sources. The system identified all correctly. Results were obtained after 4 h if heavy inocula, as suggested by the manufacturers, were used. The method may be used to aid identification of isolates of Listeria from clinical and non-clinical specimens and would be of particular value in laboratories examining small numbers of isolates relatively infrequently. Essential tests not included in the system are beta-haemolysis on sheep-blood agar and the CAMP test.

The efficacy of tobramycin in the treatment of ulcerative colitis.

This paper reports a double-blind placebo-controlled trial of oral tobramycin in acute ulcerative colitis. Eighty-four patients with an acute relapse of ulcerative colitis were randomized to receive oral tobramycin or placebo for 1 week as an adjunct to steroid therapy. At endpoint, 31 of 42 (74%) in the tobramycin group achieved complete symptomatic remission compared with 18 of 42 (43%) in the placebo group (P = 0.008). The tobramycin group achieved better histological scores (P less than 0.05) at endpoint. These findings show that treatment with oral tobramycin improves the short-term outcome of patients with ulcerative colitis in relapse.

Evaluation of the Mast ID and API 50CH systems for identification of Listeria spp.

A multipoint inoculation technique (Mast ID) for the identification and species determination of Listeria monocytogenes (sensu strictu) and six other species of the genus Listeria was evaluated. This was compared with the commercially available API 50CH system. Both methods successfully identified all 123 strains tested. The Mast ID system is inexpensive and utilizing a multipoint inoculation technique permits the screening of up to 21 isolates per 9-cm petri dish. The API 50CH system was more expensive and time consuming and is therefore suitable only for the examination of smaller numbers of strains.