Molecular epidemiology of tuberculosis in Sicily, Italy: what has changed after a decade?

Comprehensive Drug Resistance Characterization of Pulmonary Tuberculosis in Algeria: Insights on Mycobacterium tuberculosis Strains by Whole-Genome Sequencing

In this study, we aimed to characterize drug-resistant strains by whole-genome sequencing (WGS), to describe the spreading lineages and the history of transmission. Drug susceptibility testing was performed by 96-well broth microdilution plates. The genomic DNA was extracted and purified; libraries were prepared and run on the Illumina NextSeq500 System. Among 82 isolates, 21 tuberculosis (TB) isolates (25.6%) were drug resistant, including 10 MDR and 4 pre-extensively drug-resistant (XDR)-TB. The mutation Ser315Thr in the katG gene was confirmed in 15 isolates. In rpoB, Ser450Leu and His445Asp mutations were the most common. Asp94Asn and Ala90Val mutations were reported in gyrA. The LAM family, the most TB drug resistant, was widely predominant in the north and the T sublineage in the south of the country. This study provides the first insight on TB drug resistance using WGS in Algeria and clearly describes the first pre-XDR-TB cases and lineage distribution across the country.

Tuberculosis burden in immigrants and natives, adults and children, in Tuscany between 2000-2018

BACKGROUND

Updated data on epidemiology of tuberculosis are needed in Italy. The aim of this study is to evaluate trends in incidence and associated lethality of tuberculosis in immigrants compared with Italians.

METHODS

All tuberculosis cases diagnosed from 2000 to 2018 in 31 Tuscan hospitals were retrospectively identified.

RESULTS

In 10,827 tuberculosis cases 6715 were males (62%), 4312 (60%) were Italian-born. Hospitalization rate was 15.37/100,000 population/year. The most common comorbidity were liver disease (832/10,827; 7.7%), COPD (675/10,827; 6.2%), cancer (614/10,827; 5.7%). HIV was more frequent in the immigrants (p < 0.001). Extra-pulmonary tuberculosis cases (EPTB) were mainly localized in pleura (740/3,894, 19%) and lymph nodes (449/3,894, 11,5%). HIV was associated with an increased risk of EPTB (OR 3.51 95% CI 2.92-4.23, p < 0.0001). EPTB risk was increased in South Asian-born patients (OR 1.77, 95% CI 1.46-2.15, p < 0.0001) as well in African-born patients (OR 1.13, 95% CI 1.03-1.24, p = 0.0091), who were at risk for gastroenteric tuberculosis (OR 3.74, 95% CI 2.69-5.22, p < 0.0001). Overall mortality rate was 0.006 per 1000. Most of death cases (89%) were Italians (p < 0.02) and mainly affected by pulmonary tuberculosis (PTB).

CONCLUSIONS

In Tuscany, tuberculosis is still a health concern in terms of both morbidity and mortality.

Clustering and recent transmission of Mycobacterium tuberculosis in a Chinese population

Purpose

The objectives of the present study were to characterize the clinical isolates prevailing in the northeast of Jiangsu and to investigate the mode of transmission. The study also aimed to explore the extent to which Mycobacterium tuberculosis strains contributed to drug resistance and the possible factors related to the recent transmission.

Patients and methods

We consecutively enrolled 912 culture-confirmed pulmonary tuberculosis (TB) cases from 1 January 2013 to 31 December 2014 in Lianyungang City, which is located in the center of China’s vast ocean area and the northeast of Jiangsu province. Isolates were genotyped using 15-locus mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) typing. The Hunter–Gaston discrimination index (HGDI) was used to estimate the discriminatory power and diversity of molecular markers.

Results

Among 741 successfully genotyped isolates, 144 (19.43%) strains formed 46 clusters, while 597 (80.57%) isolates had the unique MIRU pattern. The total HGDI for all 15 loci was 0.999. The average cluster size was 3 (2–13) patients. The estimated proportion of recent transmission was 13.34%. Patients with unfavorable treatment outcomes were infected with clustered strains at a higher proportion than were those with favorable treatment outcomes (adjusted OR: 1.78, 95% CI: 1.14–2.85, P=0.012).

Conclusion

The probability of recent TB transmission was relatively low in the study site, while the cases mainly arose from the activation of previous infection. Spatial analysis showed that strains forming larger clusters had the characteristics of regional aggregation.

Molecular epidemiology of Mycobacterium tuberculosis complex strains isolated from livestock and wild animals in Italy suggests the need for a different eradication strategy for bovine tuberculosis

Bovine tuberculosis (bTB) is an important zoonosis, which has been re-emerging in different ecological scenarios. In Sicily, Italy, from 2004 to 2014, an anatomopathological survey for tuberculosis-like lesions both in farmed and wild animals was performed. The isolates were genotyped using spoligotyping and Mycobacterial Interspersed Repetitive Units-Variable Number of Tandem Repeats (MIRU-VNTR) techniques. High prevalence of lesions was observed for cattle (4%), pigs (4.9%) and wild boars (6.8%), and a total of 625 Mycobacterium bovis isolates were identified. Genotyping analysis showed the presence of 37 different spoligotypes including fifteen spoligotypes not present in other Italian regions and 266 MIRU-VNTR profiles. Spoligotype SB0120 exhibited the highest prevalence in cattle (50%) and pigs (56%) and the highest genetic variety with 126 different MIRU-VNTR profiles. The isolation of M. bovis in a farmer underlines the importance of M. bovis identification during the human TB diagnostic processes. This study supported the use of the genotyping analysis as a valuable tool for the evaluation of the epidemiological role of pigs and other domestic reservoirs such as goats and the role of wildlife in the maintenance of bTB infection.

Rifampicin-resistant Mycobacterium tuberculosis among tuberculosis-presumptive cases at University of Gondar Hospital, northwest Ethiopia

Background

Various studies have reported that the emergence of drug-resistant tuberculosis poses a significant threat to tuberculosis-control programs worldwide. Rifampicin resistance is a surrogate marker of multidrug-resistant tuberculosis, since it reveals the presence of greater than 90% isoniazid resistance. Evidence on rifampicin-resistant Mycobacterium tuberculosis is scarce in the literature.

Objective

To determine the prevalence of rifampicin-resistant M. tuberculosis among tuberculosis-presumptive cases at the University of Gondar Hospital.

Materials and methods

A retrospective study was conducted at the University of Gondar Hospital from January 2013 to August 2015. Data were collected from registration books using a data-extraction format after securing ethical approval and checking the completeness of necessary information. Data were double-entered and rechecked to ensure accuracy and analyzed using SPSS version 20. Results were summarized using descriptive statistics. Associations were assessed using Fisher’s exact test, and P<0.05 was considered statistically significant.

Results

A total of 1,820 M. tuberculosis-presumptive patients were included in the study. The majority of the study participants were males (59.2%). The mean age of the participants was 36.6±15.8 years. The preponderant age-group was 24–30 years, with 477 (23.5%) patients. The overall prevalence of M. tuberculosis-confirmed cases was 448 (24.6%, 95% CI 0.23–0.27). Of the 448 M. tuberculosis-confirmed cases, 71 (15.8%, 95% CI 1.12–1.19) were resistant to rifampicin. Rifampicin-resistant M. tuberculosis was observed among HIV seropositives (14 [18.7%]), males (45[17.3%]), and previously treated tuberculosis patients (61 [16.5%]), although no significant association was found in this study.

Conclusion

The overall prevalence of M. tuberculosis and rifampicin resistance was found to be high in tuberculosis patients in this study. Therefore, early detection of drug-resistant M. tuberculosis should be strengthened for management of tuberculosis patients.

Genetic diversity and molecular epidemiology of multidrug-resistant Mycobacterium tuberculosis in Minas Gerais State, Brazil

Background

We aimed to characterize the genetic diversity of drug-resistant Mycobacterium tuberculosis (MTb) clinical isolates and investigate the molecular epidemiology of multidrug-resistant (MDR) tuberculosis from Minas Gerais State, Brazil.

Methods

One hundred and four MTb clinical isolates were assessed by IS6110-RFLP, 24-locus mycobacterial interspersed repetitive units variable-number tandem repeats (MIRU-VNTR), TB-SPRINT (simultaneous spoligotyping and rifampicin-isoniazid drug-resistance mutation analysis) and 3R-SNP-typing (analysis of single-nucleotide polymorphisms in the genes involved in replication, recombination and repair functions).

Results

Fifty-seven different IS6110-RFLP patterns were found, among which 50 had unique patterns and 17 were grouped into seven clusters. The discriminatory index (Hunter and Gaston, HGDI) for RFLP was 0.9937. Ninety-nine different MIRU-VNTR patterns were found, 95 of which had unique patterns and nine isolates were grouped into four clusters. The major allelic diversity index in the MIRU-VNTR loci ranged from 0.6568 to 0.7789. The global HGDI for MIRU-VNTR was 0.9991. Thirty-two different spoligotyping profiles were found: 16 unique patterns (n = 16) and 16 clustered profiles (n = 88). The HGDI for spoligotyping was 0.9009. The spoligotyped clinical isolates were phylogenetically classified into Latin-American Mediterranean (66.34 %), T (14.42 %), Haarlem (5.76 %), X (1.92 %), S (1.92 %) and U (unknown profile; 8.65 %). Among the U isolates, 77.8 % were classified further by 3R-SNP-typing as 44.5 % Haarlem and 33.3 % LAM, while the 22.2 % remaining were not classified. Among the 104 clinical isolates, 86 were identified by TB-SPRINT as MDR, 12 were resistant to rifampicin only, one was resistant to isoniazid only, three were susceptible to both drugs, and two were not successfully amplified by PCR. A total of 42, 28 and eight isolates had mutations in rpoB positions 531, 526 and 516, respectively. Correlating the cluster analysis with the patient data did not suggest recent transmission of MDR-TB.

Conclusions

Although our results do not suggest strong transmission of MDR-TB in Minas Gerais (using a classical 100 % MDR-TB identical isolates cluster definition), use of a smoother cluster definition (>85 % similarity) does not allow us to fully eliminate this possibility; hence, around 20–30 % of the isolates we analyzed might be MDR-TB transmission cases.