Antibiotic Susceptibility of Potentially Probiotic Lactobacillus Species
Abstract:In recent years, the time-honored reputation of lactobacilli as promoters of gastrointestinal and female urogenital health has been qualified. This has occurred due to a rare association with human infection in the presence of certain predisposing factors and their potential to act as a source of undesirable antibiotic resistance determinants to other members of the indigenous micro biota. This necessitates greater caution in their selection for use in microbial adjunct nutrition and disease management (prophylaxis and therapy). It was against this background that 46 Lactobacillus strains from human and dairy sources were assayed for susceptibility to 44 antibiotics. All strains were resistant to a group of 14 antibiotics, which included inhibitors of cell wall synthesis (cefoxitin [30 μg] and aztreonam [30 μg]), protein synthesis (amikacin [30 μg], gentamicin [10 μg], kanamycin [30 μg], and streptomycin [10 μg]), nucleic acid synthesis (norfloxacin [10 μg], nalidixic acid [30 μg], sulphamethoxazole [100 μg], trimethoprim [5 μg], co-trimoxazole [25 μg], and metronidazole [5 μg]), and cytoplasmic membrane function (polymyxin B [300 μg] and colistin sulphate [10 μg]). All strains were susceptible to tetracycline (30 μg), chloramphenicol (30 μg), and rifampicin (5 μg). Four human strains and one dairy strain exhibited atypical resistance to a penicillin, bacitracin (10 μg), and/or nitrofurantoin (300 μg). One human strain was also resistant to erythromycin (15 μg) and clindamycin (2 μg). These resistances may have been acquired due to antibiotic exposure in vivo, but conclusive evidence is lacking in this regard. Seven microorganism-drug combinations were evaluated for β-lactamase activity using synergy and nitrocefin tests. The absence of activity suggested that cell wall impermeability appeared responsible for β-lactam resistance. The occurrence of a minority of lactobacilli with undesirable, atypical resistance to certain antibiotics demonstrates that not all strains are suitable for use as probiotics or bacteriotherapeutic agents. The natural resistance of lactobacilli to a wide range of clinically important antibiotics may enable the development of antibiotic/probiotic combination therapies for such conditions as diarrhea, female urogenital tract infection, and infective endocarditis.
Document Type: Research Article
Affiliations: 1: SET Consultants Ltd., Douglas, Cork, Ireland 2: National Dairy Products Research Centre, Moorepark, Cork, Ireland 3: Instituto di Microbiologia, Universita Cattolica del Sacre Coure, Piacenza, Italy 4: Microbiology Department, University College, Cork, Ireland
Publication date: December 1, 1998
- IAFP Members with personal subscriptions to JFP Online: To access full-text JFP or JMFT articles, you must sign-in in the upper-right corner using your Ingenta sign-in details (your IAFP Member Login does not apply to this website). The Journal of Food Protection (JFP) is a refereed monthly publication. Each issue contains scientific research and authoritative review articles reporting on a variety of topics in food science pertaining to food safety and quality. The Journal is internationally recognized as the leading publication in the field of food microbiology with a readership exceeding 11,000 scientists from 70 countries. The Journal of Food Protection is indexed in Index Medicus, Current Contents, BIOSIS, PubMed, Medline, and many others.
Print and online subscriptions are available to IAFP Members and institutional subscribers. IAFP Members with a subscription to JFP Online will have access to all available JFP and JMFT content. Online visitors who are not IAFP Members or journal subscribers will be charged on a pay-per-view basis. Membership and subscription information is available at www.foodprotection.org.
- Information for Authors
- Submit a Paper
- Subscribe to this Title
- Membership Information
- Information for Advertisers
- ingentaconnect is not responsible for the content or availability of external websites