ABSTRACT
Objective To study the ability of standard strain and clinical isolates of Ureaplasma spp. to form biofilms in vitro and to compare the antibiotic susceptibility of sessile cells and their planktonic counterparts. Methods A total of 21 Ureaplasma wealyticum(Uu) isolates recovered from female patients diagnosed with cervicitis and Uu serovar 3 and Uu serovar 8( Uu3, Uu8) were included. Scanning electron microscope and confocal scanning laser microscopy were used to identify biofilm formation. Conventional antibiotic susceptibility tests and biofilm susceptibility assays for tetracycline, erythromycin and ciprofloxacin were carried out. The paired rank sum test and was applied to analyze the statistical differences between the MIC and the minimal biofilm inhibitory concentration. The x2 test was applied to analyze the statistical differences of global resistance percentages between planktonic cells and sessile cells. Results Uu3, Uu8 and 21 Uu isolates all can form biofilms in vitro. Minimal inhibitory concentration of sessile cells compared with planktonic cells were obviously higher for tetracycline, erythromycin and ciprofloxacin (P <0.001). Global resistance percentages between planktonic cells and sessile cells were different for erythromycin (9.52% vs 61.90% , P < 0. 001), ciprofloxacin ( 80. 95% vs 100% , P = 0. 035 ) and tetracycline (4. 76% vs 14.29% , P =0.293). Conclusion Uu isolates and Uu1, Uu8 all can form biofilms in vitro, and biofilm formation can strengthen resistance of Uu to antibiotics, even multidrug resistance was observed.
ABSTRACT
Objective To detect the msr gene which confers resistance to erythromycin, and ana-lyze its distributing difference between the two biovars of Ureaplasma urealyticum. Methods Broth dilution method was used to determine the minimum inhibitory concentrations (MIC) to erythromycin among 72 U. urealyticum clinical isolates. The msrA, msrB, msrC and msrD genes detection and biotyping of U. urea-lyticum were conducted using PCR. Results The MICs of 72 U. urealyticum isolates to erythromycin ranged from ≤0. 125 μg/ml to ≥128 μg/ml. MIC_(50) was 32 μg/ml and MIC_(50) was ≥128 μg/ml. Biotyping showed that biovar Parvo had 51 strains (51/72, 70.83%) and biovar T960 had 21 (21/72, 29.17%) strains.The msrA, msrB, msrC and msrD genes were obtained in 1, 12, 0 and 24 strains, respectively, with five strains carrying the msrB and msrD genes, and one strain carrying the msrA, msrB and msrD genes. There was no resistance difference to erythromycin between the two biovars when the MIC≥8 μg/ml was considered resistance to eryt hromycin. But the msrB gene was predominantly detected in biovar T960. Conclusion U. urealyticum clinical isolates harbeur the msrA, msrB and msrD genes, and the predominantly detected msrB gene is of biovar T960.
ABSTRACT
Objective To study the relationship between erythromyein sensitivity and ermB gene in 143 Ureaplasma urealyticum (Uu) clinical isolates. Methods We detected the minimum inhabit concen-trations (MICs) of Uu to erythromycin by broth dilution method and MIC≥8 μg/ml was used as standard concentration of resistance to erythromycin. Polymerase chain reaction was used to detect the ermB gene and biotype Uu with primers based on multi-band antigen gene. Results The MICs, MIC50 MIC90 of Uu to erythromycin were ≤0. 125 μg/ml to ≥128 μg/ml, 16 μg/ml, and ≥128 μg/ml, respectively, with a high resistance rate of 64.38%. ermB gene, which was mainly detected in Uu with MIC≥8 μg/ml, was positively detected in 40 out of 143 Uu strains (27.97%). No significant differences of the resistance to erythromycin and positive rate of ermB gene were found between the two biovars in the study . Conclusion ermB gene may probably be one of the important genes conferring resistance to erythromycin in Uu. Further studies are needed to discover the difference of resistance and mechanism of erythromycin between the two bi-ovars.