Fluoroquinolone resistance in Mycobacterium tuberculosis has become increasingly important. A review of mutations in DNA gyrase, the fluoroquinolone target, is needed to improve the molecular detection of resistance. We performed a systematic review of studies reporting mutations in DNA gyrase genes in clinical M. tuberculosis isolates. From 42 studies that met inclusion criteria, 1220 fluoroquinolone-resistant M. tuberculosis isolates underwent sequencing of the quinolone resistance-determining region (QRDR) of gyrA; 780 (64%) had mutations. The QRDR of gyrB was sequenced in 534 resistant isolates; 17 (3%) had mutations. Mutations at gyrA codons 90, 91 or 94 were present in 654/1220 (54%) resistant isolates. Four different GyrB numbering systems were reported, resulting in mutation location discrepancies. We propose a consensus numbering system. Most fluoroquinolone-resistant M. tuberculosis isolates had mutations in DNA gyrase, but a substantial proportion did not. The proposed consensus numbering system can improve molecular detection of resistance and identification of novel mutations.

Close contacts to infectious patients with tuberculosis had high rates of tuberculosis, with most disease diagnosed before or within 3 months after the index patient' diagnosis. Contact investigations need to be prompt to detect tuberculosis and maximize the opportunity to identify and treat latent infection, to prevent disease.

Overall, fluoroquinolone resistance was relatively low. However, receipt of fluoroquinolones for more than 10 days, particularly more than 60 days before tuberculosis diagnosis, was associated with a high risk of fluoroquinolone-resistant tuberculosis.

Heteroresistance is the coexistence of populations with differing nucleotides at a drug resistance locus within a sample of organisms. Although Sanger sequencing is the gold standard for sequencing, it may be less sensitive than deep sequencing for detecting fluoroquinolone heteroresistance in Mycobacterium tuberculosis. Twenty-seven fluoroquinolone monoresistant and 11 fluoroquinolone-susceptible M. tuberculosis isolates were analyzed by Sanger and Illumina deep sequencing. Individual sequencing reads were analyzed to detect heteroresistance in the gyrA and gyrB genes. Heteroresistance to fluoroquinolones was identified in 10/26 (38%) phenotypically fluoroquinolone-resistant samples and 0/11 (P ‫؍‬ 0.02) fluoroquinolone-susceptible controls. One resistant sample was excluded because of contamination with the laboratory strain M. tuberculosis H37Rv. Sanger sequencing revealed resistance-conferring mutations in 15 isolates, while deep sequencing revealed mutations in 20 isolates. Isolates with fluoroquinolone resistance-conferring mutations by Sanger sequencing all had at least those same mutations identified by deep sequencing. By deep sequencing, 10 isolates had a single fixed (defined as >95% frequency) mutation, while 10 were heteroresistant, 5 of which had a single unfixed (defined as <95% frequency) mutation and 5 had multiple unfixed mutations. Illumina deep sequencing identified a higher proportion of fluoroquinolone-resistant M. tuberculosis isolates with heteroresistance than did Sanger sequencing. The heteroresistant isolates frequently demonstrated multiple mutations, but resistant isolates with fixed mutations each had only a single mutation.

Introduction Since 2015, the World Health Organization (WHO) has recommended that all people living with HIV (PLHIV) initiate antiretroviral treatment (ART), irrespective of CD4+ count or clinical stage. National adoption of universal treatment has accelerated since WHO's 2015 “Treat All” recommendation; however, little is known about the translation of this guidance into practice. This study aimed to assess the status of Treat All implementation across regions, countries, and levels of the health care delivery system. Methods Between June and December 2017, 201/221 (91%) adult HIV treatment sites that participate in the global IeDEA research consortium completed a survey on capacity and practices related to HIV care. Located in 41 countries across seven geographic regions, sites provided information on the status and timing of site‐level introduction of Treat All, as well as site‐level practices related to ART initiation. Results Almost all sites (93%) reported that they had begun implementing Treat All, and there were no statistically significant differences in site‐level Treat All introduction by health facility type, urban/rural location, sector (public/private) or country income level. The median time between national policy adoption and site‐level introduction was one month. In countries where Treat All was not yet adopted in national guidelines, 69% of sites reported initiating all patients on ART, regardless of clinical criteria, and these sites had been implementing Treat All for a median period of seven months at the time of the survey. The majority of sites (77%) reported typically initiating patients on ART within 14 days of confirming diagnosis, with 60% to 62% of sites implementing Treat All in East, Southern and West Africa reporting same‐day ART initiation for most patients. Conclusions By mid‐ to late‐2017, the Treat All strategy was the standard of care at almost all IeDEA sites, including rural, primary‐level health facilities in low‐resource settings. While further assessments of site‐level capacity to provide high‐quality HIV care under Treat All and to support sustained viral suppression after ART initiation are needed, the widespread introduction of Treat All at the service delivery level is a critical step towards global targets for ending the HIV epidemic as a public health threat.

MGIT 960, MODS and NRA are sensitive and specific and more rapid than PM for identifying fluoroquinolone resistance in M. tuberculosis. Ofloxacin resistance was associated with cross-resistance to ciprofloxacin, levofloxacin and moxifloxacin.

Background Close contacts of persons with pulmonary tuberculosis (TB) have high rates of TB disease. Methods We prospectively enrolled TB patients and their close contacts at 9 US/Canadian sites. TB patients and contacts were interviewed to identify index patient, contact, and exposure risk factors for TB. Contacts were evaluated for latent TB infection (LTBI) and TB, and the effectiveness of LTBI treatment for preventing contact TB was examined. Results Among 4490 close contacts, multivariable risk factors for TB were age ≤5 years, US/Canadian birth, human immunodeficiency virus infection, skin test induration ≥10 mm, shared bedroom with an index patient, exposure to more than 1 index patient, and index patient weight loss (P &lt; .05 for each). Of 1406 skin test–positive contacts, TB developed in 49 (9.8%) of 446 who did not initiate treatment, 8 (1.8%) of 443 who received partial treatment, and 1 (0.2%) of 517 who completed treatment (1951, 290, and 31 cases/100 000 person-years, respectively; P &lt; .001). TB was diagnosed in 4.2% of US/Canadian-born compared with 2.3% of foreign-born contacts (P = .002), and TB rates for US/Canadian-born and foreign-born contacts who did not initiate treatment were 3592 and 811 per 100 000 person-years, respectively (P &lt; .001). Conclusions Treatment for LTBI was highly effective in preventing TB among close contacts of infectious TB patients. Several index patient, contact, and exposure characteristics associated with increased risk of contact TB were identified. These findings help inform contact investigation, LTBI treatment, and other public health prevention efforts.

h Fluoroquinolone resistance in Mycobacterium tuberculosis can be conferred by mutations in gyrA or gyrB. The prevalence of resistance mutations outside the quinolone resistance-determining region (QRDR) of gyrA or gyrB is unclear, since such regions are rarely sequenced. M. tuberculosis isolates from 1,111 patients with newly diagnosed culture-confirmed tuberculosis diagnosed in Tennessee from 2002 to 2009 were screened for phenotypic ofloxacin resistance (>2 g/ml). For each resistant isolate, two ofloxacin-susceptible isolates were selected: one with antecedent fluoroquinolone exposure and one without. The complete gyrA and gyrB genes were sequenced and compared with M. tuberculosis H37Rv. Of 25 ofloxacin-resistant isolates, 11 (44%) did not have previously reported resistance mutations. Of these, 10 had novel polymorphisms: 3 in the QRDR of gyrA, 1 in the QRDR of gyrB, and 6 outside the QRDR of gyrA or gyrB; 1 did not have any gyrase polymorphisms. Polymorphisms in gyrA codons 1 to 73 were more common in fluoroquinolone-susceptible than in fluoroquinolone-resistant strains (20% versus 0%; P ‫؍‬ 0.016). In summary, almost half of fluoroquinolone-resistant M. tuberculosis isolates did not have previously described resistance mutations, which has implications for genotypic diagnostic tests.