Susceptibility of Ureaplasma urealyticum to Tetracycline,Doxycycline, Erythromycin,Roxithromycin, Clarithromycin,Azithromycin, Levofloxacin and Moxifloxacin

Abstract

The in vitro activity of tetracycline, doxycycline, erythromycin, roxithromycin, clarithromycin, azithromycin, levofloxacin and moxifloxacin was tested against 63 clinical isolates of Ureaplasma urealyticum. The minimal inhibitory concentrations (MICs) and the minimal bactericidal concentrations (MBCs) were determined by the broth microdilution method in A7 medium. The miC50 and miC90 of the tested agents after 24 h of incubation were as follows: Tetracycline, 0.5 and 2.0 μg/ml; doxycycline, 0.125 and 0.25 μg/ml; erythromycin, 2.0 and 8.0 μg/ml; roxithromycin, 2.0 and 4.0 μg/ml; clarithromycin, 0.25 and 1.0 μg/ml; azithromycin, 2.0 and 4.0 μg/ml; levofloxacin, 1.0 and 2.0 μg/ml; and moxifloxacin, 0.5 and 0.5 μg/ml, respectively. The MIC values after 24 h and 48 h incubation differed by no more than one dilution for all the agents with the exception of doxycycline (two dilution difference for MIC₉₀). Overall, moxifloxacin was the most active agent in vitro against U. Urealyticum, with the narrowest difference between MIC and MBC values, followed closely by levofloxacin. Clarithromycin was the most active macrolide.     

An Update on Invasive Pneumococcal Antibiotic Resistance in Turkey, 2008

Abstract

Cumulative pneumococcal antibiotic resistance profiles in Turkey in 2008, verified from local studies are as follows: penicillin 35%, cefotaxime 2%, ceftriaxone 1%, trimethoprim-sulfamethoxazole 39%, tetracycline 19%, erythromycin 18%, azithromycin 18%, clarithromycin 10%, ofloxacin 13%, clindamycin 9%, chloramphenicol 5%, rifampicin 2%, levofloxacin 2%, moxifloxacin 0%, gemiloxacin 0%, telithromycin 0%, vancomycin 0%.     

In vitro selection of resistance to clarithromycin in Streptococcus pneumoniae clinical isolates

In this study the effects of exposure to serum, lung and breakpoint concentrations on Streptococcus pneumoniae susceptibility to clarithromycin, azithromycin, amoxicillin/clavulanate, levofloxacin and moxifloxacin were evaluated. Development of resistance was determined by multi-step and single-step methodologies. In the first experimental set, minimum inhibitory concentrations (MICs) were determined after 10 passages on antibiotic-gradient plates and 10 passages on antibiotic-free plates. Acquisition of resistance was defined as an increase of > or = 4-fold from the starting MIC. In single-step studies, the rate of spontaneous mutations was calculated after a passage on antibiotic-containing agar plates. Azithromycin and levofloxacin gave the highest number of strains with MIC increased of at least 4 times the starting value, followed by moxifloxacin and by clarithromycin which only at the lowest concentration tested selected for resistance in 5 strains. Amoxicillin/clavulanate never displayed > or = 4-fold MIC increase. Frequencies of mutation were lower for clarithromycin and moxifloxacin than for the comparators. At lung concentrations clarithromycin had limited potential to select for resistance.     

Antimicrobial susceptibility profile of contemporary clinical strains of Stenotrophomonas maltophilia isolates: can moxifloxacin activity be predicted by levofloxacin MIC results?

The susceptibility profile of 763 Stenotrophomonas maltophilia isolates was evaluated against 16 antimicrobials by the CLSI reference broth microdilution method. Minocycline (MIC(90), 1 microg/ml; 100.0% susceptible) was the most active compound, followed by doxycycline (MIC(90), 4 microg/ml; 99.6% susceptible), trimethoprim/sulfamethoxazole (MIC(90), 1 microg/ml; 97.8% susceptible), and tigecycline (MIC(90), 2 microg/ml). An excellent correlation between levofloxacin (MIC(90), 4 microg/ml; 86.5% susceptible by published breakpoint criteria) and moxifloxacin (MIC(90), 2 micro g/ml) MIC results was observed indicating that moxifloxacin could be further evaluated as a therapeutic option for S. maltophilia infections.     

Moxifloxacin sensitivity of respiratory pathogens in the United Kingdom

The in vitro activity of moxifloxacin and comparator agents against respiratory isolates from a range of geographically distinct centres around the United Kingdom was investigated in the following study. Clinical isolates of Streptococcus pneumoniae (n = 257), Haemophilus influenzae (n = 399) and Moraxella catarrhalis (n = 253) were obtained between March 1998 and April 1999 from nine centres in the United Kingdom. Sensitivity was determined by testing each isolate for its minimum inhibitory concentration (MIC) by agar dilution. Against Streptococcus pneumoniae moxifloxacin and grepafloxacin were the most active (MIC90 = 0.25 mg/l). Trovafloxacin and sparfloxacin were the next most active (MIC90 = 0.5 mg/l) followed by levofloxacin and ciprofloxacin. MIC90 values of the six fluoroquinolones versus H. influenzae ranged from <0.0039 mg/l to 0.0625 mg/l and from <0.0039 mg/l to 0.5 mg/l for M. catarrhalis. The rank order of activity of the fluoroquinolones versus H. influenzae was moxifloxacin = trovafloxacin = grepafloxacin = sparfloxacin > ciprofloxacin > levofloxacin. Against M. catarrhalis the lowest MIC90 was that of grepafloxacin at 0.0625 mg/l followed by moxifloxacin, sparfloxacin, levofloxacin and ciprofloxacin. Trovafloxacin demonstrated the highest MIC90 at 0.5 mg/l. These results demonstrate that moxifloxacin has superior in vitro activity against respiratory tract pathogens than any other comparator quinolones available for clinical use.     

In vitro activity of tigecycline, tetracycline and fluoroquinolones against Brucella melitensis

Brucellosis is a major zoonotic disease of global importance. Forty years after active drug therapy was defined, there is no optimum antibiotic therapy for brucellosis due to relatively high rates of relapse and treatment failure. The aim of this study was to assess the in vitro susceptibility of 60 Brucella melitensis isolates obtained from blood and fluids to tigecycline, tetracycline and three quinolones (ciprofloxacin, levofloxacin, moxifloxacin). The minimum inhibitory concentrations (MICs) of these antibiotics were determined by E-test method. According to the MIC90, levofloxacin (MIC90 0.094 microg/mL) was found to be the most active agent, followed by tigecycline (MIC90 0.125 microg/mL), moxifloxacin (MIC90 0.125 microg/mL), ciprofloxacin (MIC 90 0.19 microg/mL) and tetracycline (MIC90 0.25 microg/mL). The results suggest that tigecycline can be a therapeutic alternative option for the treatment of brucellosis.     

In-vitro activity of roxithromycin against Chlamydia trachomatis

Ten Chlamydia trachomatis isolates were tested for their sensitivity to roxithromycin, in comparison with erythromycin and tetracycline. The minimum inhibitory and minimum bactericidal concentrations of roxithromycin ranged from 0.03-0.12 and 0.25-1 microg/ml, respectively.     

Peritoneal carcinomatosis from ovarian cancer: cytoreductive surgery and intraperitoneal chemotherapy

Abstract

We tested the in vitro bactericidal activity of moxifloxacin, a new 8-methoxyquinolone, alone and in combination with vancomycin or teicoplanin at different multiples of minimum inhibitory concentration (MIC) against 8 methicillin-ciprofloxacin-resistant Staphylococcus aureus (M-C-RSA) and 1 methicillin-ciprofloxacin susceptible S. aureus (M-C-SSA) recently isolated from device-associated infections unresponsive to or relapsing after glycopeptide therapy, despite device removal. MICs of vancomycin ranged from 1 to 4 μg/ml, MICs of teicoplanin ranged from 2 to 8 μg/ml; MICs of moxifloxacin were always 2 μg/ml against M-CRSA isolates and 0.125 μg/ml against the M-C-SSA isolate. The 9 strains resulted tolerant when tested for vancomycin, teicoplanin, and moxifloxacin used alone at 2xMIC. In all cases the combination of moxifloxacin and teicoplanin or vancomycin appeared to be bactericidal already at MIC concentration for glycopeptides plus 0.5xMIC concentration for moxifloxacin. If these results are confirmed in vivo in animal experiments, the combination of moxifloxacin with glycopeptides might be useful for treating device-associated infections, and in preventing the frightening phenomenon of increasing MICs for glycopeptides.     

The role of newer macrolides in the treatment of community-acquired respiratory tract infection. A review of experimental and clinical data.

The macrolide class of antibiotics is well established and often recommended for use in the treatment of community-acquired respiratory tract infection (RTI). The newer agents clarithromycin and azithromycin are frequently prescribed as first- or second-line therapy, and have been considered as superior to erythromycin in microbiological activity and clinical efficacy. In-vitro data show that clarithromycin and azithromycin have good activity (MIC < or = 0.5 microg/ml) against certain RTI pathogens. However the activity of both compounds is intrinsically low against Haemophilus influenzae whilst several other important RTI pathogens - notably Streptococcus pneumoniae and Streptococcus pyogenes - exhibit a high prevalence of resistance to them. In many countries, the prevalence of resistance to clarithromycin and azithromycin is still rising with cross resistance with erythromycin. Maximum serum concentrations of clarithromycin and azithromycin are lower than the MIC90s for these agents against H. influenzae and S. pneumoniae. Concentrations in tissues have been reported to be much higher than those in serum. However, the high concentrations observed in tissues are largely a reflection of high concentrations inside cells. Concentrations of clarithromycin and azithromycin in extracellular tissue fluids, where Haemophilus and streptococci are located, are in equilibrium with concentrations in the serum, and remain low. It has been suggested that phagocytes deliver azithromycin to infection sites in a targeted fashion, but the evidence in support of this hypothesis is weak. Recent clinical experience with clarithromycin and azithromycin is consistent with preclinical results, and suggests that these agents have limited efficacy against certain respiratory infections. Clarithromycin and azithromycin are the first choice treatment of atypical infections caused by intracellular pathogens. For community-acquired RTIs, where H. influenzae and S. pneumoniae are present, they may no longer be an appropriate choice for first-line therapy. Indeed, in areas where levels of drug resistant S. pneumoniae are high, their use may be questionable as second-line therapy.     

In Vitro Activity of HMR 3647 Against Anaerobic Bacteria

Abstract

The aim of the present investigation was to determine the In Vitro activity of HMR 3647 compared with other antimicrobial agents against anaerobic bacteria. The activity of HMR 3647 was determined against 342 clinical isolates of anaerobic bacteria by the agar dilution method and was compared with azithromycin, clarithromycin, roxithromycin, erythromycin, cefoxitin, imipenem, clindamycin and metronidazole.

Among the macrolides HMR 3647 and among the beta-lactams imipenem were the most active agents tested. Anaerobic cocci (50 strains) had the following minimum inhibitory concentrations (MICs): HMR 3647, range 0.016-0.125 mg/l; imipenem, range 0.016-0.064 mg/l. Propionibacterium acnes (30 strains): HMR 3647, 0.016-1.0 mg/l; imipenem, 0.032-0.064 mg/l. Clostridium perfringens (30 strains): HMR 3647, 0.125 mg/l; imipenem, 0.016-0.5 mg/l. Clostridium difficile (50 strains): HMR 3647, 0.125-256 mg/l; imipenem, 4.0-8.0 mg/l. Bacteroides fragilis (102 strains): HMR 3647, 0.032-16 mg/l; imipenem, 0.064-0.25 mg/l. Bacteroides and Prevotella species (50 strains): HMR 3647, 0.016-4.0 mg/l; imipenem, 0.016-0.25 mg/l. Fusobacterium nucleatum (30 strains): HMR 3647, 0.016-8.0 mg/l; imipenem, 0.008-0.064 mg/l.

HMR 3647 may be useful as treatment and prophylaxis for infections due to anaerobic bacteria.     

Evaluation of Moxifloxacin Activity In Vitro Against Mycobacterium tuberculosis,Including Resistant and Multidrug-Resistant Strains

Abstract

The new quinolone moxifloxacin was tested against 86 strains of Mycobacterium tuberculosis including 13 resistant and 4 multiresistant strains. The antimicrobial susceptibility was tested, in parallel, using two different liquid media, the radiometric Bactec 12B and the Mycobacteria Growth Indicator Tube (Becton Dickinson, USA). All strains but two were susceptible at 0.5 μg/ml of moxifloxacin; for the remaining two strains, both multidrugresistant, the minimal inhibitory concentrations (MIC) were =2 and >4 >g/ml respectively. Our data confirm the high antitubercular in vitro activity of moxifloxacin.     

Susceptibility of penicillin-resistant and penicillin-susceptible Streptococcus pneumoniae to newer antimicrobial agents.

Agar dilution minimum inhibitory concentration (MIC) methodology, according to NCCLS guidelines, was used to test the activity of three glycopeptides (LY 333328 [LY], vancomycin [VAN], and teicoplanin [TEI]), four fluoroquinolones (trovafloxacin [TRO], BAY 12-8039 [BAY], ciprofloxacin [CIP], and ofloxacin [OFL]), five macrolide-lincosamide-streptogramin antibiotics (erythromycin [ERY], azithromycin [AZI], miocamycin [MOM], clindamycin CLN], and quinupristin-dalfopristin [SYN] against 126 Streptococcus pneumoniae strains, isolated in Lozano Blesa Hospital of Zaragoza (Spain). MIC50/MIC90 (microg/ml) values for penicillin-susceptible (PS), penicillin-intermediate (PI) and penicillin-resistant (PR) strains show an excellent antipneumococcal activity of LY 333326--a new glycopeptide, for the fluoroquinolones trovafloxacin and moxifloxacin [BAY 12-8039], and for quinupristin/dalfopristin, regardless of the resistance phenotype of the strains.     

In Vitro Activity of Cefpirome (HR 810) against Enterococci and Staphylococci

Summary

The inhibitory activity of cefpirome (HR 810), a new cephalosporin derivative for parenteral use, was tested by agar dilution methods against Enterococcus faecatis (100 strains), Staphylococcus aureus (40 strains) and coagulase-negative staphylococcal species (60 strains) in comparison with other beta-lac ta m antibiotics.

For E. faecalls, the cefpirome minimum inhibitory concentration (MIC) range was 2-128 μg/ml, with an MIC,, of 8 μg/ml, and an MIC₉₀, of 64 μg/ml. The optimal bactericidal activity against strains with MICs of ≤ 8 μg/ml occurred at 2-4 times the MIC, and the reduction in the initial inoculum was 99.9-99.7% after 24 h incubation at these concentrations.

Mec gene-negative staphylococci (both S. aureus and coagulase- negative species) had cefpirome MICs of 0.25-2 μg/ml (MIC₅₀ 0.5 μg/ml, MIC₉₀ 1 μg/ml). Mec gene-positive strains had MICs of 0.5-128 μg/ml (MIC₅₀ 2 μg/ml, MIC₉₀ 32 μg/ml). Strains with borderline resistance to oxacillin which did not harbor the mec gene and which were susceptible to cefpirome maintained their susceptibility even when high-density inocula were used and after several passages in media containing the antibiotic.

These studies present some potential advantages of cefpirome over other cephalosporins in the inhibitory activity against Gram-positive cocci.     

In Vitro Activity of Lomefloxacin (SC-47111) Against Enterobacteriaceae,Enterococci and Staphylococci

Summary

The activity of lomefloxacin, a new difluorinated quinolone, was tested against 190 Enterobacteriaceae strains (belonging to 23 different species), 70 enterococci and 70 staphylococci. As regards Enterobacteriaceae, the activity of lomefloxacin was the same as that of norfloxacin in 9 out of the 23 species tested, and only slightly lower in further 8 species. Minimum inhibitory concentrations (MIC) values for 90% of strains were 0.5 μg/ml in 2 species, 0.25 μg/ml in 6, 0.125 μg/ml in 4, and lower than 0.125 μg/ml in 8. Slightly higher values were obtained for Serratia marcescens (2 μg/ml), whilst, as already reported for the other new quinolones, the susceptibility of the Providencia genus was very poor, with MIC values up to 128 μg/ml for the vast majority of strains. Lomefloxacin proved bactericidal at the MIC in all the Enterobacteriaceae strains tested but 20. In the latter strains, however, bactericidal activity could be appreciated at values slightly exceeding MIC. As regards enterococci, the MIC for 90% of strains was 32 μg/ml. Minimum bactericidal concentration (MBC) was the same as the MIC for 78% of the strains tested and was only twofold higher in all the others. The new drug was also active against staphylococci having an MIC50 and MIC₉₀ of 0.5 and 2 μg/ml, respectively. It was bactericidal at the MIC for 62% of the strains and at twofold the MIC for all the others.     

Determination of the Susceptibility In Vitro of 54 Isolates of Mycobacterium fortuitum against Three Fluoroquinolones Using Two Methods

Abstract

The In Vitro susceptibility to ofloxacin, norfloxacin and ciprofloxacin or 54 Mycobacterium fortuitum isolates originating from clinical samples (7) of patients attending the Hospital Universitario de Canarias and Hospital del Tórax, and from environmental (47) sources, were determined. For this, two methods were used: dilution in agar with Middlebrook 7H10 Agar as a base medium culture, and broth microdilution, with Mueller-Hinton Broth without supplement.

The different isolates under study revealed a uniform susceptibility by both methods against ciprofloxacin.

100% inhibition was obtained from a Minimum Inhibitory Concentration (MIC) of 0.25 μg/ml, and 2 μg/ml of ciprofloxacin, for broth microdilution and dilution in agar, respectively.

For ofloxacin and norfloxacin, all the isolates were inhibited at an MIC of 0.5 μ/ml, by the broth microdilution method, which contrasted sharply with an MIC of 32 μ/ml, in the case of dilution in agar.

In this study, we have observed the existence of differences in the In Vitro susceptibility of the isolates of M. fortuitum against the three fluoroquinolones assayed, mainly for ofloxacin and norfloxacin, by both methods. We, therefore, consider it necessary to establish a standardized, reproducible assay method, for the study of sensitivity to atypical mycobacteria.     

Antimicrobial resistance among respiratory pathogens collected in Thailand during 1999-2000

A multi-center surveillance study was conducted in Thailand during 1999-2000 to determine antimicrobial susceptibilities among the respiratory pathogens Streptococcus pneumoniae (n = 206), Haemophilus influenzae (n = 305), and Moraxella catarrhalis (n = 39). Of the S. pneumoniae isolates collected, 33.5% were penicillin-susceptible, 27.2% intermediate and 39.3% resistant. Expectedly, resistance rates to beta-lactams were higher among penicillin-resistant (ceftriaxone, 14.8%; amoxicillin-clavulanate, 42.0%; cefuroxime, 100%) than penicillin-susceptible (ceftriaxone, 0%; amoxicillin-clavulanate, 0%; cefuroxime, 0%) isolates. Likewise, azithromycin and clarithromycin resistances were 4.3% and 5.8% among penicillin-susceptible isolates, and 77.8% and 95.1% among penicillin-resistant isolates. All S. pneumoniae remained susceptible to vancomycin and 99.5% were susceptible to levofloxacin. Multidrug resistance (resistance to >3 antimicrobial classes) was present in 25.2% of pneumococcal isolates (n = 52), with resistance to azithromycin, penicillin and trimethoprim-sulfamethoxazole the most common phenotype (40/52 isolates; 77.0%). Among the isolates of H. influenzae, the prevalence of beta-lactamase production was 45.2%. All isolates of H. influenzae were susceptible to amoxicillin-clavulanate, azithromycin, ceftriaxone, cefuroxime and levofloxacin while 49.5% were resistant to trimethoprim-sulfamethoxazole. All 39 isolates of M. catarrhalis produced beta-lactamase. Azithromycin (MIC90, < or = 0.03 microg/ml) and levofloxacin (MIC90, 0.03 microg/ml) were the most active agents tested against M. catarrhalis. The results of this study may serve as a baseline for future studies to monitor antimicrobial susceptibilities among respiratory pathogens in Thailand.     

Comparative in vitro activity of PH-027 versus linezolid and other anti-anaerobic antimicrobials against clinical isolates of Clostridium difficile and other anaerobic bacteria

PH-027 is a new 5-triazole oxazolidinone synthesized in our laboratories, which shows strong activity against gram-positive aerobic bacteria including clinical isolates. The objective of this study was to investigate the in vitro activity of this compound in comparison with linezolid and other antibiotics against gram-positive and gram-negative anaerobes. The in vitro activity of PH-027 in comparison with those of linezolid and other antimicrobial agents was evaluated against 201 clinical isolates of gram-positive and gram-negative anaerobic bacteria by agar dilution and Etest methods. PH-027 showed excellent activity, with minimum inhibitory concentrations (MIC) in the range of 0.12-4.0 microg/ml against all isolates; MIC90s being 4.0, 1.0, 2.0, 2.0 and 2.0 microg/ml against Clostridium difficile, Peptostreptococcus spp., Bacteroides fragilis, Prevotella bivia and Fusobacterium spp. respectively. In comparison, linezolid had MIC in the range of 0.5-4.0 microg/ml against all isolates, with MIC90s of 2.0, 4.0, 4.0, 4.0 and 2.0 microg/ml against the same set of bacteria respectively. PH-027 demonstrated excellent in vitro activity that is superior to linezolid against Peptostreptococcus spp., B. fragilis and P. bivia. However, against C. difficile and Fusobacterium spp, PH-027 and linezolid showed comparable in vitro activity. Against all anaerobes, metronidazole, PH-027 and, to a lesser extent, linezolid had the most potent activity. From the results of in vitro susceptibility testing, both linezolid and PH-027 show promise in the treatment of anaerobic infections.     

Prosthetic Biologic Valve Endocarditis Caused by a Vancomycin-Resistant (vanA) Enterococcus faecalis: Case Report

Abstract

We recently observed (February 1999) a 68-year old patient with endocarditis on a prosthetic biologic valve caused by a vancomycin-resistant Enterococcus faecalis. Broth dilution tests showed susceptibility to ampicillin (MIC=0.5 μg/ml), no high resistance to aminoglycosides (MIC for gentamicin <500 μg/ml) and resistance to vancomycin (MIC >256 μg/ml) and teicoplanin (MIC>16 μg/ml). A PCR assay detected vanA gene in this strain. A trans-thoracic echocardiogram did not show valvular vegetations. A possible endocarditis was diagnosed and the patient received ampicillin for 8 weeks and gentamicin for 6 weeks. The patient remained afebrile after a 4-month follow-up when he underwent surgical replacement of the dysfunctional bioprosthetic valve. Mitral valve was sterile on culture, but histology confirmed the diagnosis of previous endocarditis. This is the third case of endocarditis caused by vancomycin-resistant E. faecalis reported to date.     

Levofloxacin vs. azithromycin pharmacodynamic activity against S. pneumoniae and H. influenzae with decreased susceptibility to amoxicillin/clavulanic acid

Resistant clones/phenotypes are putting into question the activity of commonly used beta-lactams, thus prompting the need for alternative options. A 500 mg levofloxacin vs. azithromycin once daily pharmacodynamic simulation was performed against 10(8) cfu/ml of four Streptococcus pneumoniae strains (exhibiting higher amoxicillin than penicillin MIC) and four Haemophilus influenzae strains: beta-lactamase producing, BLNAR (beta-lactamase-negative ampicillin-resistant) and BLPACR (beta-lactamase-positive amoxicillin/clavulanate-resistant). High levofloxacin AUC/MIC values for H. influenzae, and values of 50-100 for S. pneumoniae produced a >5 log(10) reduction at 24h for all strains. Azithromycin AUC/MIC values of approximately 10 were needed to obtain a 2-3 log(10) reduction of S. pneumoniae initial inocula, but lower AUC/MIC values (of approximately 6) obtained > or =3 log(10) reduction against all strains of H. influenzae. While in vitro simulated serum concentrations of levofloxacin were bactericidal at the end of the dosing interval against all S. pneumoniae strains and azithromycin against the susceptible ones, both antimicrobials achieved this endpoint against the BLNAR and BLPACR strains.     

In Vitro Antifungal Activity of Sertaconazole Against 309 Dermatophyte Clinical Isolates

Abstract

Three hundred and nine strains belonging to 11 species of dermatophyte moulds were tested against sertaconazole following mainly the National Committee for Clinical Laboratory Standards (M38-P) for filamentous fungi. However, several important factors such as the temperature (28°C vs 35°C) and time of incubation (4-10 d vs 21-74 h), have been modified. Sertaconazole was active against all the clinically important dermatophyte moulds involved in human infections tested. Overall geometric mean MIC of sertaconazole was 0.21 μg/ml with a MIC range of 0.01-8 μg/ml. MIC₅₀ and MIC₉₀ were respectively of 0.25 and 1 μg/ml. Sertaconazole was very active against Epidermophyton floccosum, Trichophyton rubrum, Trichophyton tonsurans and Microsporum canis (geometric means 0.08, 0.13, 0.13 and 0.19 μg/ml respectively). Microsporum audouinii had the lowest susceptibility in the study (geometric mean 0.59 μg/ml). Considering MIC₅₀ and MIC₉₀ these differences were significantly in favor of the activity of sertaconazole against E. floccosum (0.06 and 0.5 μg/ml respectively).