Drug resistance and the genotypic characteristics of rpoB and katG in rifampicin- and/or isoniazid-resistant Mycobacterium tuberculosis isolates in central Vietnam.

BACKGROUND: Tuberculosis (TB) and drug-resistant TB (DR-TB) are national health burdens in Vietnam. In this study, we investigated the prevalence of rifampicin (RIF) and/or isoniazid (isonicotinic acid hydrazide, INH) resistance in patients with suspected TB, and applied appropriate techniques to help rapidly target DR-TB. METHODS: In total, 1,547 clinical specimens were collected and cultured using the BACTEC MGIT system (Becton Dickinson and Co.). A resazurin microtiter assay (REMA) was used to determine the proportions of RIF and/or INH resistance. A real-time polymerase chain reaction panel with TaqMan probes was employed to identify the mutations of rpoB and katG associated with DR-TB in clinical isolates. Genotyping of the identified mutations was also performed. RESULTS: A total of 468 Mycobacterium tuberculosis isolates were identified using the REMA. Of these isolates, 106 (22.6%) were found to be resistant to 1 or both antibiotics. Of the resistant isolates, 74 isolates (69.8%) were resistant to isoniazid (INH) only, while 1 isolate (0.94%) was resistant to RIF only. Notably, 31 isolates (29.24%) were resistant to both antibiotics. Of the 41 phenotypically INH-resistant isolates, 19 (46.3%) had the Ser315Thr mutation. There were 8 different rpoB mutations in 22 (68.8%) of the RIF-resistant isolates. The most frequently detected mutations were at codons 531 (37.5%), 526 (18.8%), and 516 (6.3%). CONCLUSION: To help prevent new cases of DR-TB in Vietnam, it is crucial to gain a comprehensive understanding of the genotypic DR-TB isolates.

Genotyping of Mycobacterium leprae strains in south central coast and central highlands of Vietnam.

Background and Objectives: Leprosy remains an important health problem worldwide. It is one of the oldest recorded diseases of humankind. In this study, we expanded the analysis of the geographic distribution of Mycobacterium leprae by investigating SNPs and rpoT genotypes in South Central Coast and Central Highlands clinical isolates, providing insights into the distribution and transmission of leprosy in Vietnam and in this geographic region. Materials and Methods: 27 clinical isolates from the patients, determined the genotypes of M. leprae by SNP and rpoT polymorphism. SNP genotyping was performed by PCR amplification and sequencing, rpoT genotyping by PCR amplification and electrophoresis. Results: All of 27 DNA samples (100%) were positive with RLEP TaqMan PCR (Ct value range is 18-32 on 3 replicates). SNP type 1 was identified in 15 isolates (56%), while SNP type 3 was detected in 12 samples (44%). SNP type 2 and type 4, were not detected. The 6-base repeat region of the rpoT gene was amplified by PCR and analyzed by 4% MetaPhor™ agarose gel electrophoresis. All isolates yielded amplification products of 91-bp, but not 97-bp. Conclusion: This study showed that 56% of isolates belonged to type 1, 44% to type 3. In addition, all samples have the 3-copy hexamer genotype in the rpoT gene.

First Molecular Detection of Zoonotic Chlamydia Species in Vietnamese Goats.

The genus Chlamydia comprises obligate intracellular bacteria that infect a wide variety of hosts, with infection leading to a range of diseases in humans and animals; they thus constitute a major public health threat. Among the members of the Chlamydiaceae family, Chlamydia suis, C. abortus, C. pecorum, and C. psittaci represent the most important pathogenic species infecting a large range of hosts and are a well-established threat to livestock. Information regarding the circulation of Chlamydia species in ruminants from Vietnam is lacking. In this study, DNA extracted from 60 blood samples collected from goats in Hue province was used for Chlamydia spp. identification by classic PCR and Sanger sequencing. Chlamydia spp. were detected in eleven samples (18.3%) and C. abortus and C. psittaci were molecularly identified by sequencing. Despite the limited sample size in this study, findings point out the relevance of ruminants as hosts of chlamydial species in Central Vietnam and the importance of monitoring chlamydial strains through the activation of surveillance programs in this country. The need for a deeper evaluation of human and animal health risk analysis in terms of chlamydiosis should be also considered.

Case of misdiagnosed melioidosis from Hue city, Vietnam.

Melioidosis is an emerging infection, a potentially fatal tropical disease caused by Burkholderia pseudomallei in humans and animals, endemic in Southeast Asia and northern Australia. Diagnosis remains problematic due to its similarity to many other infections. The lack of clinical awareness and correct microbiological diagnosis contributes to the misidentification of melioidosis. We present a melioidosis case, which was misdiagnosed with pneumonia and septicemia due to Aeromonas salmonicida, leading to ineffective prolonged-course antibiotic treatment for the patient.

Community-based prevalence versus hospital-based incidence of genital Human Papillomavirus infection in Central Vietnam.

INTRODUCTION: This study aims to determine the genital HPV prevalence in reproductive-age women in Thua Thien Hue Province and comparison with HPV incidence in Hue University Hospital, Vietnam. METHODOLOGY: Cross-sectional study on 1,034 women of reproductive age from 11 communes/wards of three districts representing three different geographic areas of Thua Thien Hue Province, Vietnam. The hospital-based group included 102 women with cervicitis and/or abnormal Pap smear result coming to Hue University Hospital. Extracting DNA from cervical samples, performing the real-time PCR for detecting HPV and the reverse dot-blot assay for HPV typing in HPV positive cases. RESULTS: In community, HPV prevalence was 0.9%. Mean-age of HPV positive group was 37.9 ± 6.2 years. The detected low-risk types were 6 and 11; high-risk types include 16, 18, 33, 45, 52, and 58. Single-type infection was found in 66.7% of cases. In hospital-based group, 41.2% of women have been infected with HPV, 6 different HPV types were detected. HPV18 was the most frequent high-risk type (33.3%), followed by HPV16 (15.1%); HPV6 was the most frequent among low-risk HPV types (31.2%). Single-type infection rate was 33,3%; 2 and 3 types co-infections were 28,6% and 38.1%, respectively. CONCLUSIONS: Routine screening of high-risk HPV infection in women with symptomatic gynecologic infection and/or abnormal Pap smear appears to be benefit in early detection and prevention of cervical cancer, due to the high incidence of HPV infection.