Article

Emergence of phenotypic resistance to ciprofloxacin and levofloxacin in methicillin-resistant and methicillin-sensitive Staphylococcus aureus strains.

Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Ege University, 35100 Bornova, Izmir, Turkey.
International Journal of Antimicrobial Agents (Impact Factor: 4.42). 06/2003; 21(5):420-4. DOI: 10.1016/S0924-8579(03)00006-2
Source: PubMed

ABSTRACT The emergence of phenotypic resistance to ciprofloxacin and levofloxacin in methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MRSA) strains was studied. Twenty MRSA and 77 methicillin-sensitive S.aureus (MSSA) strains susceptible to both quinolones were investigated for resistance after single step or serial passages. No growth of 20 MRSA strains was observed at 4xMIC of levofloxacin after 48 h incubation, but 4 of 77 (5%) MSSA strains grew at the same concentration. At 4xMIC concentration of ciprofloxacin, 10 MSSA (13%) and five MRSA (25%) strains were grown. In the serial passages of MRSA strains, resistance to ciprofloxacin was 75 and 5% for levofloxacin by the third passage. In the seventh passage this resistance was 100 and 15%, respectively. In MSSA strains, resistance to ciprofloxacin was 75 and 19% to levofloxacin at the third passage and at the seventh passage, 100 and 61%, respectively. Emergence of ciprofloxacin resistance was more common and developed more rapidly than resistance to levofloxacin in both MRSA and MSSA strains.

0 Bookmarks
 · 
45 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: Methicillin-resistant Staphylococcus aureus (MRSA) otorrhea has become an increasing problem with regard to infection through the tympanic membrane perforation and postsurgical infection. In particular, dry ear, at the preoperative stage, is considered to be a crucial factor in surgery. We evaluated how to control MRSA otorrhea before and after ear surgery. Twenty-six patients having MRSA otorrhea were enrolled in the present study and randomly divided into 2 groups, namely, mupirocin ointment therapy for 16 patients and ofloxacin ear drops for 10 patients. Approximately 0.6 mg of mupirocin ointment was administered locally to the tympanic membrane and the promontory around and through the perforation with its adjacent external ear canal 1 to 4 times for 2 or 3 weeks at the clinic. On the other hand, ofloxacin ear drops were administered daily by the patients for 2 or 3 weeks at home. Complete elimination of MRSA from the ear was obtained in all patients of the mupirocin group. This showed a significant improvement (p < 0.001) as compared with the ofloxacin group (improvement + cure rate, 40%). Local application of mupirocin did not aggravate hearing acuity of any patients who were evaluated by pure-tone audiometry before and after treatment. The present findings first indicate that minimally essential application of mupirocin ointment is an extremely useful ototopical agent against MRSA otorrhea without ototoxicity.
    Otology & neurotology: official publication of the American Otological Society, American Neurotology Society [and] European Academy of Otology and Neurotology 09/2008; 29(5):676-8. · 1.44 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Nuclear medicine imaging techniques offer whole body imaging for localization of number and site of infective foci inspite of limitation of spatial resolution. The innate human immune system contains a large member of important elements including antimicrobial peptides to combat any form of infection. However, development of antibiotics against bacteria progressed rapidly and gained popularity over antimicrobial peptides but even powerful antimicrobials failed to reduce morbidity and mortality due to emergence of mutant strains of bacteria resulting in antimicrobial resistance. Differentiation between infection and inflammation using radiolabeled compounds with nuclear medicine techniques has always been a dilemma which is still to be resolved. Starting from nonspecific tracers to specific radiolabeled tracers, the question is still unanswered. Specific radiolabeled tracers included antibiotics and antimicrobial peptides which bind directly to the bacteria for efficient localization with advanced nuclear medicine equipments. However, there are merits and demerits attributed to each. In the current paper, radiolabeled antibiotics and radiolabeled peptides for infection localization have been discussed starting with the background of primitive nonspecific tracers. Radiolabeled antimicrobial peptides have certain merits compared with labeled antibiotics which make them superior agents for localization of infective focus.
    International Journal of Peptides 01/2012; 2012:965238.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Antibiotic use in French hospitals is among the highest in Europe. A study was carried out to describe antibiotic consumption for inpatients at hospital and at ward levels. Data were voluntarily collected retrospectively by 530 hospitals accounting for approximately 40 million patient-days (PD) on the following: antibacterials for systemic use [J01 class of the WHO Anatomical Therapeutic Chemical (ATC) classification, defined daily doses (DDD) system, 2007], rifampicin and oral imidazole derivatives, expressed in number of DDD and number of PD in 2007. Consumption was expressed in DDD/1000 PD. Median antibiotic use ranged from 60 DDD/1000 PD in long-term care (LTC) and psychiatric hospitals to 633 DDD/1000 PD in teaching hospitals. Penicillins and beta-lactamase inhibitors combinations were the most frequently used antibiotics, accounting for 26% of total use in cancer hospitals to 40% in LTC/psychiatric hospitals. Glycopeptides and carbapenems were mostly used in cancer and teaching hospitals. Level of consumption and pattern of use differed according to clinical ward from 60 DDD/1000 PD in psychiatric wards up to 1466 DDD/1000 PD in intensive care units (ICUs). In medicine, surgery, ICU and rehabilitation wards, fluoroquinolones accounted for 13%-19% of the total use. This multicentre survey provided detailed information on antibiotic use in a large sample of hospitals and wards, allowing relevant comparisons and benchmarking. Analysis of consumption at the ward level should help hospitals to target practice audits to improve antibiotic use.
    Journal of Antimicrobial Chemotherapy 09/2010; 65(9):2028-36. · 5.34 Impact Factor