The First Macrolide-Resistant Bordetella pertussis Strains Isolated From Iranian Patients.

BACKGROUND: Whooping cough was considered as one of the major causes of childhood morbidity and mortality worldwide. Resistant isolates of Bordetella pertussis to macrolides in some countries have been recently reported. OBJECTIVES: Recent reports on macrolide-resistant B. pertussis isolates and lack of evidence for such resistance in clinical isolates of the Iranian patients led the authors of the current study to study antibiotic susceptibility of the collected isolates in the country. Susceptibility of the B. pertussis isolates to three antibiotics was studied. Relatedness of the strains recovered in this research was also examined. MATERIALS AND METHODS: The antibacterial activities of erythromycin, azithromycin, and clarithromycin antibiotics against the recovered isolates of 779 nasopharyngeal swabs were examined using MIC (Minimum Inhibitory Concentration) method. Relationship of the strains was characterized by Pulsed-field Gel Electrophoresis (PFGE). RESULTS: Among the specimens, 11 cases (1.4%) were culture-positive. Among these isolates, only two isolates had high MIC values for erythromycin and clarithromycin. Pulsed-field gel electrophoresis analysis of the isolates revealed 6 PFGE profiles (A-F) among which three and two isolates had the same patterns in profiles A and B, respectively. CONCLUSIONS: Azithromycin can be a good drug of choice to treat patients infected by B. pertussis in Iran. Clonal relationship of the isolates showed that the same B. pertussis strains were isolated from different patients in Iran.

Comparison of culture and real-time PCR for detection of Bordetella pertussis isolated from patients in Iran.

BACKGROUND AND OBJECTIVE: Due to contagiousness of pertussis, a rapid and sensitive method for diagnosis is required to initiate the treatment and interrupt its transmission. MATERIALS AND METHODS: To detect B. pertussis strains, we used two real-time PCR targeting IS481 and BP283 sequences and compared factors influencing culture and real-time PCR results. RESULTS: Totally, 779 specimens were collected from patients among which 11 (1.4%) were culture positive. Using IS481 and BP283 primers, 122 (15.6%) and 100 (12.8%) were diagnosed as infected specimens respectively. There were significant relationships between the real-time PCR method for diagnosis of B. pertussis and age, sex and vaccination of patients before sampling. CONCLUSION: The real-time PCR is superior and much more sensitive than culture for diagnosis of B. pertussis. However, the sensitivity was improved when both IS481 and BP283 were used. Correct sampling and transportation of specimen also improved the detection rate in our research.

Ribotyping and increasing trend of antibiotic resistance of Pseudomonas aeruginosa isolated in Iran

The trend of antibiotic resistance, ribotyping and serotyping patterns of Pseudomonas aeruginosa collected since 1987 in Iran were investigated. The results showed that among the aminoglycosides, amikacin was the most effective antibiotic against P. aeruginosa with 98.4 percent susceptibility rate followed by tobramycin (73 percent) and gentamicin (71 percent). Of the cephalosporins, susceptibility to ceftazidime was 93 percent. Among the antibiotics tested in vitro, ciproflaxacin was found to be the most effective against the strains, with 98.4 percent susceptibility rate. The most predominant monovalent serotype was O:11 (34 percent). Other dominant serotypes were O:5 (20 percent), O:1 (16 percent) and O:6 (15 percent). Thirteen percent of the isolates showed no agglutination with the tested sera. A high percent of the O:11 serotype isolates (68 percent) were resistant to > or = 3 antibiotics. The collected P. aeruginosa isolates were classified into 3 ribotypes using PuvII restriction enzyme. The results suggest that the antibiotic resistance among P. aeruginosa increased significantly rate in Iran in the last decades, with no changes in the ribotype and serotype patterns.

Investigou-se o perfil de resistência a antibióticos, os ribotipos e os sorotipos de Pseudomonas aeruginosa isolada no Irã a partir de 1987. Os resultados indicaram que, entre os antibióticos testados, a amicacina foi o antibiótico mais eficiente, com 98.4 por cento de inibição, seguida por tobramicina (73 por cento) e gentamicina (71 por cento). Entre as cefalosporinas, a sensibilidade a ceftazidima foi 93 por cento. Entre os antibióticos testados in vitro, ciprofloxacina foi a mais eficiente. O sorotipo de maior prevalência foi O:11 (34 por cento). Outros sorotipos encontrados foram O:5 (20 por cento) e O:6 (15 por cento). Treze por cento dos isolados não aglutinaram com os soros utilizados. Uma elevada porcentagem dos isolados pertencentes ao sorotipo O:11 foi resistente a pelo menos três antibióticos. Utilizando-se a enzima de restrição PuvII, as cepas foram classificadas em três ribotipos. Os resultados sugerem que a resistência a antibióticos em P. auruginosa aumentou significantemente nas últimas décadas, sem modificação dos padrões de ribotipos e sorotipos.