Trend of microbiologically-confirmed tuberculosis in a low-incidence setting with high immigration rates

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.

Tuberculosis-Related Hospitalizations in a Low-Incidence Country: A Retrospective Analysis in Two Italian Infectious Diseases Wards

In recent years, a decrease in the incidence of tuberculosis (TB) has been recorded worldwide. However, an increase in TB cases has been reported in foreign people living in low-incidence countries, with an increase in extrapulmonary TB (EPTB) in the western region of the world. In the present work, a retrospective study was conducted in two Italian infectious diseases wards to evaluate the clinical characteristics of TB admission in the time period 2013-2017. A significant increase in TB was shown in the study period: 166 (71% males) patients with TB were enrolled, with ~70% coming from outside Italy (30% from Africa, 25% from Europe, and 13% from Asia and South America). Compared to foreign people, Italians were significantly older (71.5 (interquartile range, IQR: 44.5-80.0) vs. 30 (IQR: 24-40) years; p < 0.0001) more immunocompromised (48% vs. 17%; p < 0.0001), and affected by comorbidities (44% vs. 14%; p < 0.0001). EPTB represented 37% of all forms of the disease, and it was more incident in subjects coming from Africa than in those coming from Europe (39.3% vs. 20%, respectively). In logistic regression analysis, being European was protective (odd ratio, OR (95% CI): 0.2 (0.1-0.6); p = 0.004) against the development of EPTB forms. In conclusion, an increase in the rate of TB diagnosis was documented in two Italian reference centers in the period 2013-2017, with 39% of EPTB diagnosed in patients from outside Europe.

First-line tuberculosis drug resistance patterns and associated risk factors in Germany, 2008-2017

Background

Drug-resistant tuberculosis (TB), especially multidrug-resistant TB (MDR-TB), poses a threat to public health. While standard surveillance focuses on Rifampicin and/or Isoniazid resistance, little is known about other resistance patterns. This study aims to identify predominant drug resistance (DR) patterns in Germany and risk factors associated with them in order to inform diagnostic and treatment strategies.

Methods

Case-based TB surveillance data notified in Germany from 2008–2017 were utilized to investigate DR and MDR-TB patterns for Isoniazid (H), Rifampicin (R), Pyrazinamide (Z), Ethambutol (E), and Streptomycin (S). Predominant patterns were further analyzed stratified by sex, age, country of birth, prior TB, and disease site. Multivariable logistic regression was conducted to determine risk factors associated with any resistance, MDR-TB, and complete HRZES resistance.

Results

26,228 cases with complete DST results were included in the study, among which 3,324 cases had any DR (12.7%). Four patterns were predominant, representing about ¾ of all cases with any resistance (S: 814 [3.1%]; H: 768 [2.9%]; HS: 552 [2.1%]; Z: 412 [1.6%]). High proportions of S and H resistances were found among both German and foreign-born populations, especially those born in Eastern Europe, and were unexpectedly high among children (H: 4.3%; S: 4.6%). Foreign-born cases had significantly higher proportion of any resistance (16.0%) and MDR-TB (3.3%) compared to German-born cases (8.3% and 0.6%). Of 556 MDR-TB cases, 39.2% showed complete HRZES resistance. Logistic regression revealed having prior TB and being foreign-born as consistently strong risk factors for any DR, MDR-TB, and complete HRZES resistance.

Conclusions

DR patterns observed in Germany, particularly for MDR-TB were more complex than expected, highlighting the fact that detailed drug-testing results are crucial before incorporating HRZES drugs in MDR-TB treatment. Furthermore, the relatively high rate of H-resistance in Germany provides strong rationale against the use of only H-based preventive therapy for LTBI.

Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF

BACKGROUND

Diagnosis of pulmonary (PTB) and extra-pulmonary tuberculosis (EPTB) in smear-negative patients can be difficult. We assessed retrospectively the performance of Xpert MTB/RIF system (Xpert, Cepheid) in diagnosing smear-negative tuberculosis (TB), which represents the most common form of TB in a low incidence setting.

METHODS

Performance of Xpert was compared to acid-fast microscopic examination using Ziehl-Neelsen (ZN) stain in patients with culture-confirmed TB.

RESULTS

386 Mycobacterium tuberculosis (MTB) culture-positive samples were detected out of 5170 specimens tested with smear microscopy, Xpert and culture: 323 were both culture- and Xpert-positive, and 63 culture-positive only. Of these, 234 (60.6%) were smear-negative. In addition Xpert detected 40 probable TB cases, based on clinical findings, which were culture-negative. Compared to culture, Xpert showed an overall sensitivity of 83.7% and a specificity of 99.1%; sensitivity was higher for respiratory samples (86.5%) than for non-respiratory samples (76.8%). Xpert sensitivity for smear-negative culture-confirmed TB was 73.1% and was not influenced by TB localization. As sensitivity of microscopy alone was poor (39.4%), Xpert improved both diagnosis of pulmonary TB (Δ = 36.5%) and extra-pulmonary TB (Δ = 63.4%).

CONCLUSIONS

Xpert MTB/RIF is a sensitive method for rapid diagnosis of TB compared to the conventional ZN staining. Xpert can serve as a sensitive and time-saving diagnostic method for microbiological diagnosis of smear-negative TB in countries with a low TB prevalence.

Identifying risk factors associated with smear positivity of pulmonary tuberculosis in Kazakhstan

Background

Sputum smear-positive tuberculosis (TB) patients have a high risk of transmission and are of great epidemiological and infection control significance. Little is known about the smear-positive populations in high TB burden regions, such as Kazakhstan. The objective of this study is to characterize the smear-positive population in Kazakhstan and identify associated modifiable risk factors.

Methods

Data on incident TB cases’ (identified between April 2012 and March 2014) socio-demographic, risk behavior, and comorbidity characteristics were collected in four regions of Kazakhstan through structured survey and medical record review. We used multivariable logistic regression to determine factors associated with smear positivity.

Results

Of the total sample, 193 (34.3%) of the 562 study participants tested smear-positive. In the final adjusted multivariable logistic regression model, sex (adjusted odds ratio (aOR) = 2.0, 95% CI:1.3–3.1, p < 0.01), incarceration (aOR = 3.6, 95% CI:1.2–11.1, p = 0.03), alcohol dependence (aOR = 2.6, 95% CI:1.2–5.7, p = 0.02), diabetes (aOR = 5.0, 95% CI:2.4–10.7, p < 0.01), and physician access (aOR = 2.7, 95% CI:1.3–5.5p < 0.01) were associated with smear-positivity.

Conclusions

Incarceration, alcohol dependence, diabetes, and physician access are associated with smear positivity among incident TB cases in Kazakhstan. To stem the TB epidemic, screening, treatment and prevention policies should address these factors.

[Comparative study of concordance and costs between tuberculin skin test and QuantiFERON(®)-TB Gold In-Tube in the diagnosis of latent tuberculosis infection among contacts of patients with pulmonary tuberculosis]

INTRODUCTION

Recently diagnosis of latent tuberculosis infection (LTBI) can be made using the tuberculin skin test (TST) or by techniques known as interferon-γ release assays (IGRAS), being QuantiFERON(®)-TB Gold In-Tube (QF-G-IT) the most used. The IGRAS avoid some drawbacks of the TST, especially cross-reaction with bacillus Calmette-Guérin (BCG) vaccine, but also present some problems such as those arising from cost and the need of having an adequate infrastructure and experience. There is no clear consensus on which technique should be preferentially used for the diagnosis of LTBI.

METHODS

This is a comparative study between the TST and QT-G-IT in a cohort of contacts of patients with pulmonary tuberculosis during the study period. An analysis of global agreement and groups was performed according to whether the contacts were vaccinated with BCG or not. A study of costs of both techniques and diagnostic strategies based on these techniques was performed.

RESULTS

The agreement between TST and QF-G-IT was acceptable in the whole sample yet it was very good in the unvaccinated group. Few cases of indeterminate values were recorded. The cost study showed that TST was cheaper than QF-G-IT; however when we analyzed the cost of the strategies according to each technique, the QF-G-IT showed a better cost-benefit.

CONCLUSION

We suggest considering QF-G-IT as the only preferred technique for the diagnosis of LTBI in household contacts, based on good overall agreement between the 2 techniques (even if we eliminate the effect of the vaccine) and a cost analysis favorable to QF-G-IT.