Prevalence of erm genes encoding macrolide-lincosamide-streptogramin (MLS) resistance among clinical isolates of Staphylococcus aureus in a Turkish university hospital.

This study investigated the prevalence of the erm(A), erm(B) and erm(C) genes among 122 MLS-resistant clinical isolates of Staphylococcus aureus from a Turkish university hospital. Of these isolates, 44 were inducibly resistant and 78 were constitutively resistant. The presence of one or more erm genes was demonstrated in 114 isolates; the erm(C) gene was detected in 97 isolates, and the erm(A) gene was detected in 96 isolates. Seventy-eight isolates harboured both erm(A) and erm(C). The combination of erm(A), erm(B) and erm(C) genes was detected in only one isolate.

Use of fluorescence resonance energy transfer for rapid detection of isoniazid resistance in Mycobacterium tuberculosis clinical isolates.

SETTING: Rapid detection of drug resistance in Mycobacterium tuberculosis is important to select effective treatment and prevent transmission of resistant isolates. OBJECTIVE: To evaluate the use of fluorescence resonance energy transfer (FRET) for rapid detection of isoniazid (INH) resistance in M. tuberculosis clinical isolates. DESIGN: One hundred INH-resistant and 50 INH-susceptible isolates of M. tuberculosis were included in the study. The drug susceptibility of all isolates was determined by the standard agar proportion method, and all isolates were then tested by FRET. Three genes associated with INH resistance, katG, inhA and ahpC, were analysed. All isolates were amplified with three pairs of primers. Three pairs of fluorescently labelled DNA probes specific to codon 315 of katG, nucleotide 209 in the regulatory region of inhA and a frequent mutation site in the intergenic region of oxyR-ahpC, were used for mutation detection. RESULTS: The results obtained using FRET were compared with those from the proportion method. The sensitivity and specificity of FRET were respectively 76% and 100%. The frequencies of mutations were 48% in katG, 17% in inhA, 8% in ahpC, 2% in inhA-ahpC and 1% in inhA-katG. CONCLUSION: FRET is a rapid, specific method that can be useful to detect INH resistance in M. tuberculosis clinical isolates.

Induction of mycobacteremia by intravesical bacillus Calmette-Guerin instillation in an experimental animal model and detection with polymerase chain reaction.

PURPOSE: The aim of this study was to detect mycobacteremia by polymerase chain reaction (PCR), induced by the instillation of bacillus Calmette-Guerin (BCG) to guinea pig bladder. We also investigated the peak time and the effect of the dose of BCG in injured and non-injured bladder. The sensitivities of routine culture and PCR were also compared. MATERIALS AND METHODS: Five different doses (0, 0.069, 0.69, 6.9 and 69 mg.) of BCG were instilled into 5 injured and 5 non-injured bladders. Blood samples were collected at 0, 5, 15, 30 and 60 minutes following instillation for routine culture and PCR for each dose. A total of 50 female guinea pigs were used. RESULTS: Three of 5 samples (60%) obtained 30 minutes after the instillation of 69 mg. BCG into injured bladders were PCR positive. Furthermore, 4 of 5 samples (80%) were PCR positive when samples were obtained at the 60th minute following instillation. All the other samples were negative for PCR and routine culture. All the routine tuberculosis culture results were negative, including those which were PCR positive. CONCLUSIONS: Mycobacteremia was detected only in injured bladders and with high doses of BCG. PCR is a highly sensitive and rapid diagnostic method for detection of mycobacteremia.