Antibiotic Susceptibility of Stenotrophomonas (Xanthomonas) maltophilia: Comparative (NCCLS Criteria) Evaluation of Antimicrobial Drugs with the Agar Dilution and the Agar Disk Diffusion (Bauer-Kirby) Tests

Traub, Walter H.; Leonhard, Birgit; Bauer, Dierk

doi:10.1159/000007111

Cited by 19 publications

(23 citation statements)

References 49 publications

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“…As previously reported (4), a high level of agreement among these techniques was obtained (data not shown). Trimethoprim-sulfamethoxazole resistance was detected in 26.2% of strains, which is higher than the rates (0% to 10%) previously reported (4,5,18). Different methodologies and breakpoints could be responsible for these differences.…”

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confidence: 58%

“…On the other hand, independent studies have demonstrated methodological problems associated with susceptibility testing of S. maltophilia (4,6,7,18). In our study, in the absence of specific NCCLS recommendations for S. maltophilia, the agar dilution technique was used, but MICs were read after a full 24-h incubation at 35°C (13).…”

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confidence: 96%

“…Susceptibility testing of this combination is particularly problematic in S. maltophilia, and different results have been observed when different methods and conditions were used (4,7,18). In our study, susceptibility was assayed with both agar dilution and E-test strips on MuellerHinton agar supplemented with 0.1 U of thymidine phosphorylase per ml in order to interfere with thymidine that may be present in the medium.…”

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confidence: 98%

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Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains

Valdezate

Vindel

Loza

et al. 2001

Antimicrob Agents Chemother

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Susceptibility to 41 antimicrobials was studied with 99 Stenotrophomonas maltophilia strains, and different pulsed-field gel electrophoresis profiles were identified among 130 prospectively collected isolates. Moxalactam, doxycycline, minocycline, and clinafloxacin displayed the highest activity (>98% susceptibility). Ticarcillin resistance (75%) was reverted by clavulanate in 25% of strains. Trimethoprim-sulfamethoxazole resistance was 26.2% (>4 [trimethoprim]/76 [sulfamethoxazole] g/ml) and dropped to 11.1% when an 8/152-g/ml breakpoint was applied based on its bimodal MIC distribution. Resistance was lower when unique strains were considered, because clonal organisms contribute to resistance.

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confidence: 58%

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confidence: 96%

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confidence: 98%

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Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains

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Vindel

Loza

et al. 2001

Antimicrob Agents Chemother

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“…Levofloxacin has been reported to exert good in vitro activity on S. maltophilia (3,15); nevertheless, the observed percentages of ciprofloxacin-susceptible (58.9%) and intermediate (18.5%) strains were high between the two studies (3,15). Such a result is probably due to assay variations (14,16). S. epidermidis isolates were more susceptible to levofloxacin than ciprofloxacin, mainly when they were oxa-R, as described by Cafiso et al (4), who found levofloxacin to exert 30% more activity than ciprofloxacin on oxa-R coagulasenegative staphylococci.…”

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confidence: 99%

Levofloxacin and Ciprofloxacin In Vitro Activities against 4,003 Clinical Bacterial Isolates Collected in 24 Italian Laboratories

Gesu

Marchetti²,

Piccoli

et al. 2003

Antimicrob Agents Chemother

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Levofloxacin showed comparable in vitro susceptibility to ciprofloxacin among Enterobacteriaceae, Pseudomonas aeruginosa, enterococci, and Staphylococcus aureus, while greater susceptibility was observed in Stenotrophomonas maltophilia and Staphylococcus epidermidis, mainly when oxacillin resistant. The susceptibility of Streptococcus pneumoniae to levofloxacin reached 99%.The recent introduction of levofloxacin, a new fluoroquinolone (FQ), into the Italian clinical scenario led to the need to locally confirm its in vitro activity. Nowadays, only qualitative studies on selected bacterial species have been reported with levofloxacin in Italy (1,3,4,5,6,10,13) but larger studies on clinical isolates are missing. We report here the major findings of a survey carried out on the bacterial species most frequently encountered in the routine work of 24 Italian laboratories distributed Italywide (see Acknowledgments).Each center was requested to collect 194 consecutive, no-copy clinical isolates belonging to a predefined list of bacterial species without any limitation on the ward and/or sample of isolation. All the isolates had to be identified according to the laboratory method used to obtain them. Participants were asked to limit the number of collected Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis strains to 30 each per center. The MICs of levofloxacin and ciprofloxacin were determined locally by the Etest (AbBiodisk) method according to the manufacturer's instructions. All the assays were performed on MuellerHinton agar except for Streptococcus pneumoniae and Moraxella catarrhalis, which were tested by using MuellerHinton agar plus 5% sheep blood, and Haemophilus influenzae, which was tested by using Haemophilus test medium (all media were from the same batch). Susceptibility breakpoints were Յ2 g/ml for levofloxacin and Յ1 g/ml for ciprofloxacin according to NCCLS (11). To contain intralaboratory variability, quality controls with E. coli strain ATCC 25922, S. pneumoniae strain ATCC 49619, and H. influenzae strain ATCC 49247 were requested of each center before, during, and after the study's conclusion. The Etest method was selected because of its reliability in testing FQs (9), its ease of use, and its definition of the MIC. Between January and November 2000, case report forms for a total of 4,003 clinical isolates were collected. The quality control results confirmed that the Etest assays were carried out properly during the study, and any center results had to be discharged. As reported by others (9), a slight overestimation (1.6%) of the ciprofloxacin MIC for E. coli ATCC 25922 occurred, but the increase never determined a change in the category. Detailed figures on the isolation wards, samples, and the samples' FQ susceptibilities will be published elsewhere. The isolates and their susceptibilities to levofloxacin and ciprofloxacin are illustrated in Table 1. The Enterobacteriaceae were unhomogeneously susceptible to the study drugs, with a percentage of susceptible strains ranging fr...

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“…Antibiotic susceptibility to ampicillin, apramycin, chloramphenicol, ciprofloxacin, carbenicillin, cephalothin, erythromycin, gentamicin, imipenem, kanamycin, naladixic acid, rifampin, sulfisoxazole, streptomycin, tetracycline, trimethroprin, trimethroprim-sulfamethoxazole, and norfloxacin was determined by the BauerKirby antibiotic disk diffusion method, which was performed according to the recommendations of the National Committee for Clinical Laboratory Standards using Mueller-Hinton agar (Difco) containing 1% NaCl (47,65).…”

Section: Methodsmentioning

confidence: 99%

Characterization of Vibrio fluvialis -LikeStrains Implicated in Limp LobsterDisease

Tall

Fall

Pereira

et al. 2003

Appl Environ Microbiol

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Studies were undertaken to characterize and determine the pathogenic mechanisms involved in a newly described systemic disease in Homarus americanus (American lobster) caused by a Vibrio fluvialis-like microorganism. Nineteen isolates were obtained from eight of nine lobsters sampled. Biochemically, the isolates resembled V. fluvialis, and the isolates grew optimally at 20°C; none could grow at temperatures above 23°C. The type strain (1AMA) displayed a thermal reduction time (D value) of 5.77 min at 37°C. All of the isolates required at least 1% NaCl for growth. Collectively, the data suggest that these isolates may embody a new biotype. Pulsed-field gel electrophoresis (PFGE) analysis of the isolates revealed five closely related subgroups. Some isolates produced a sheep hemagglutinin that was neither an outer membrane protein nor a metalloprotease. Several isolates possessed capsules. The isolates were highly susceptible to a variety of antibiotics tested. However, six isolates were resistant to erythromycin. Seventeen isolates harbored plasmids. Lobster challenge studies revealed that the 50% lethal dose of a plasmid-positive strain was 100-fold lower than that of a plasmid-negative strain, suggesting that the plasmid may enhance the pathogenicity of these microorganisms in lobsters. Microorganisms that were recovered from experimentally infected lobsters exhibited biochemical and PFGE profiles that were indistinguishable from those of the challenge strain. Tissue affinity studies demonstrated that the challenge microorganisms accumulated in heart and midgut tissues as well as in the hemolymph. Culture supernatants and polymyxin B lysates of the strains caused elongation of CHO cells in tissue culture, suggesting the presence of a hitherto unknown enterotoxin. Both plasmid-positive and plasmid-negative strains caused significant dose-related intestinal fluid accumulations in suckling mice. Absence of viable organisms in the intestinal contents of mice suggests that these microorganisms cause diarrhea in mice by intoxication rather than by an infectious process. Further, these results support the thermal reduction data at 37°C and suggest that the mechanism(s) that led to fluid accumulation in mice differs from the disease process observed in lobsters by requiring neither the persistence of viable microorganisms nor the presence of plasmids. In summary, results of lobster studies satisfy Koch's postulates at the organismal and molecular levels; the findings support the hypothesis that these V. fluvialis-like organisms were responsible for the originally described systemic disease, which is now called limp lobster disease.Catastrophic losses of Homarus americanus (American lobster) have been most consistently associated with gaffkemia, a disease caused by Aerococcus viridans subsp. homari (52,59). Recognized more than half a century ago as a cause of heavy mortalities in natural populations and impounded lobsters on the east coast of North America, infection usually results when A. viridans breaches the integu...

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Antibiotic Susceptibility of Stenotrophomonas (Xanthomonas) maltophilia: Comparative (NCCLS Criteria) Evaluation of Antimicrobial Drugs with the Agar Dilution and the Agar Disk Diffusion (Bauer-Kirby) Tests

Cited by 19 publications

References 49 publications

Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains

Antimicrobial Susceptibilities of Unique Stenotrophomonas maltophilia Clinical Strains

Levofloxacin and Ciprofloxacin In Vitro Activities against 4,003 Clinical Bacterial Isolates Collected in 24 Italian Laboratories

Characterization of Vibrio fluvialis -LikeStrains Implicated in Limp LobsterDisease

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