Mycoplasma pneumoniae and Mycoplasma genitalium are important causative agents of infections in humans. Like all other mycoplasmas, these species possess genomes that are significantly smaller than that of other prokaryotes. Moreover, both organisms possess an exceptionally compact set of DNA recombination and repair-associated genes. These genes, however, are sufficient to generate antigenic variation by means of homologous recombination between specific repetitive genomic elements. At the same time, these mycoplasmas have likely evolved strategies to maintain the stability and integrity of their 'minimal' genomes. Previous studies have indicated that there are considerable differences between mycoplasmas and other bacteria in the composition of their DNA recombination and repair machinery. However, the complete repertoire of activities executed by the putative recombination and repair enzymes encoded by Mycoplasma species is not yet fully understood. In this paper, we review the current knowledge on the proteins that likely form part of the DNA repair and recombination pathways of two of the most clinically relevant Mycoplasma species, M. pneumoniae and M. genitalium. The characterization of these proteins will help to define the minimal enzymatic requirements for creating bacterial genetic diversity (antigenic variation) on the one hand, while maintaining genomic integrity on the other.

Background Tuberculosis is one of the major causes of death globally. The problems become even more complicated with the rise in prevalence of multidrug resistant tuberculosis (MDR-TB). Many diseases have been reported to occur with tuberculosis making it more difficult to manage. Candida spp., which are yeast-like fungi and a constituent of normal flora in humans, are notoriously reported to be one of the most common opportunistic nosocomial infections. This study aimed to measure the proportion of presumptive MDR-TB patients colonized with Candida spp. and to characterize its susceptibility against azole group antifungal agents. Methods Sputum from presumptive MDR-TB patients were collected and examined for the presence of Mycobacterium tuberculosis and its rifampicin resistant status using GeneXpert. It was further cultured on Sabouroud’s Dextrose Agar (SDA) to isolate the Candida spp. The Candida species were determined using HiCrome™ Candidal Differential Agar. Antifungal susceptibility was tested using microbroth dilution methods. Checkerboard microdilution assays were performed to measure the interaction between rifampicin and fluconazole to C. albicans. Results There were 355 presumptive MDR-TB patients enrolled. A total of 101 (28.4%) patients were confirmed to have M. tuberculosis. There were 113 (31.8%) sputum positive for Candida spp., which corresponded to 149 Candida spp. isolates. Candida albicans was the most frequent (53.7%) species isolated from all patients. The susceptibility of Candida spp. against fluconazole, itraconazole, and ketoconazole were 38.3%, 1.3%, and 10.7% respectively. There was significant association between rifampicin exposure history and susceptibility of Candida albicans against fluconazole (Odds Ratio: 9.96; 95% CI: 1.83–54.19; p <0.01), but not for ketoconazole and itraconazole. The checkerboard microdilution assays showed that rifampicin decreased the fungicidal activity of fluconazole to C. albicans in a dose-dependent manner. Conclusion There was high frequency of azole resistant Candida spp. isolates colonizing the respiratory tract of presumptive MDR-TB patients. This presence might indicate the association of chronic exposure to rifampicin, the main drug for tuberculosis therapy, with the induction of azole resistance.

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Recent outbreaks of human coronaviruses, officially named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have put health authorities worldwide on a high alert. Firstly emerged in the city of Wuhan, China, SARS-CoV-2 infection is rapidly escalating into a global pandemic. It is first thought as the result of a zoonotic transmission event, similar to the previous epidemic of coronaviruses. However, a continuously increasing number of confirmed cases indicates that the virus gains capacity of efficient human-to-human transmission. Soon after the pandemic is arising, many efforts are focused on identifying the origin of SARS-CoV-2 infection in the human population. Current evidence suggests that the virus is probably derived from bat or pangolin coronaviruses as the natural host. Whether intermediate host(s) exist in the transmission cascade from bat or pangolin to humans is, to a great extent, elusive. This information is essential as the basis for infection prevention and control measures. In this review, we discuss our recent understanding of SARS-CoV-2 biology, highlighting its origin and molecular evolution. ABSTRAKSaat ini, kita sedang menghadapi wabah yang disebabkan oleh human corona virus, yang secara resmi diberi nama severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Wabah ini medapatkan perhatian yang luas dari berbagai institusi kesehatan di seluruh dunia. Dilaporkan pertama kali terjadi di kota Wuhan, Cina, wabah SARS-CoV-2 secara cepat telah menyebar ke banyak negara dan berkembang menjadi pandemi. Diduga awalnya bahwa virus SARS-CoV-2 ini berasal dari transmisi hewan kemanusia, sama seperti wabah coronaviruses sebelumnya. Akan tetapi, jumlah kasus terkonfirmasi yang semakin meningkat, menunjukkan indikasi bahwa virus SARS-CoV-2 telah memiliki kapasitas untuk menular secara efektif dari manusia ke manusia. Segera setelah wabah terjadi, berbagai studi difokuskan untuk melacak asal urus virus SARS-CoV-2 sebelum menginfeksi manusia. Buktibukti terkini menunjukkan bahwa SARS-CoV-2 kemungkinan berasal dari coronaviruses yang bersirkulasi di bats (kelelawar) atau pangolins. Apakah terdapat intermediate host antara kelelawar atau pangolins dan manusia, masih belum jelas. Informasi semacam ini sangat penting sebagai dasar tindakan pencegahan dan pengendalian wabah. Pada artikel ini, kami membahas tentang biologi virus SARS-CoV-2, dengan fokus pada asal usul dan evolusi virus tersebut.