Source document: https://docs-lawep.s3.us-east-2.amazonaws.com/1697749554908.pdf (Georgia)
INT J TUBERC LUNG DIS 12(5):513–519 © 2008 The Union Prevalence and risk factors for latent tuberculosis infection among health care workers in Georgia V. Mirtskhulava,*†‡ R. Kempker,†‡ K. L. Shields,† M. K. Leonard,† T. Tsertsvadze,§ C. del Rio,†‡ A. Salakaia,* H. M. Blumberg†‡ * National Center for Tuberculosis and Lung Diseases/National Tuberculosis Program, Tbilisi, Georgia; † Division of Infectious Diseases, Emory University School of Medicine, Atlanta, Georgia, ‡ Department of Epidemiology, Emory University Rollins School of Public Health, Atlanta, Georgia, USA; § Department of Infectious Diseases, AIDS and Clinical Immunology Research Center, Tbilisi, Georgia S U M M A R Y B A C K G R O U N D : Tuberculosis (TB) is a major public health problem in Georgia, but few TB infection con- trol measures have been implemented in health care facilities.
O B J E C T I V E : To assess the prevalence and risk factors for latent TB infection (LTBI) among Georgian health care workers (HCWs) using two diagnostic tests, the tu- berculin skin test (TST) and the QuantiFERON®-TB Gold In Tube test (QFT-3G), an interferon-gamma release assay.

M E T H O D S : A cross-sectional study was conducted be- tween June and August 2006 among HCWs at the Geor- gian National TB Program.
R E S U L T S : Of 265 HCWs enrolled, 177 (67%) had a positive TST and 159 (60%) had a positive QFT-3G; 203 (77%) had a positive result for at least one of the tests and 50% tested positive for both tests.

There was mod- erately good agreement between the tests (74%, kappa 0.43, 95%CI 0.33–0.55).
In multivariate analysis, em- ployment for 5 years was associated with increased risk of a positive TST (OR 5.09, 95%CI 2.77–9.33) and QFT-3G (OR 2.26, 95%CI 1.27–4.01); age 30 years was associated with an increased risk of a positive QFT- 3G (OR 2.91, 95%CI 1.32–6.43).

D I S C U S S I O N : A high prevalence of LTBI was found among Georgian HCWs and longer duration of employ- ment was associated with increased risk.
These data highlight the need for effective TB infection control mea- sures and provide important baseline information as TB infection control measures are implemented.
K E Y W O R D S : tuberculosis infection; IFN- assay; noso- comial transmission; tuberculin skin test NOSOCOMIAL TRANSMISSION of Mycobacterium tuberculosis from patients to health care workers (HCWs) has been recognized for many years; the risk of transmission is greatest in facilities with a high bur- den of infectious tuberculosis (TB) cases.1–3 Transmis- sion of TB in health care facilities can be reduced or prevented with the implementation of effective infec- tion control measures.4,5 A hierarchy of TB infection control measures, including administrative, engineer- ing and respiratory protection controls, is recom- mended by the US Centers for Disease Control and Prevention (CDC) and others to prevent nosocomial transmission of TB.6 These measures have proven ef- fective in preventing nosocomial transmission, and administrative controls are most important.5,7 The World Health Organization (WHO) published guidelines on the prevention of TB in health care fa- V Mirtskhulava and R Kempker contributed equally to this study.
cilities in resource-limited areas in 19998 and an ad- dendum to those guidelines in 2006 entitled, ‘Tuber- culosis infection control in the era of expanding HIV care and treatment’.9 These WHO guidelines also em- phasize the importance of administrative controls for early recognition and detection of persons with TB and separation of patients with TB or suspected of having TB from other patients in health care facilities.
However, despite these recommendations, TB infec- tion control measures are virtually non-existent in most resource-limited countries (which account for 90% of the global TB burden), where emphasis is on active TB cases.2,10 The importance of TB infection control measures has been highlighted most recently by re- ports of the development and spread of extensively drug-resistant TB (XDR-TB), which is associated with high morbidity and mortality, especially among human immunodeﬁciency virus (HIV) infected persons.11 TB, including multidrug-resistant TB (MDR-TB, de- fined as resistance to at least isoniazid and rifampicin), Correspondence to: Veriko Mirtskhulava, National Center for Tuberculosis and Lung Diseases/National Tuberculosis Pro- gram, 50 Maruashvili Street, Tbilisi 0101, Georgia.
Tel: (995) 99 796104.

Fax: (995) 32 910252; 32 911941. e-mail: verikomir@yahoo.com Article submitted 12 July 2007.

Final version accepted 14 January 2008.

514 The International Journal of Tuberculosis and Lung Disease has re-emerged as a major public health problem in the country of Georgia following the collapse of the Soviet Union.
* In 2005, a total of 6448 TB cases were reported, with an incidence and prevalence of respec- tively 97 and 147 cases per 100 000 population (Sala- kaia, unpublished).

Medical care for TB in Georgia is provided through the National Tuberculosis Program (NTP) at in-patient and out-patient facilities.

TB in- fection control measures in Georgian health care fa- cilities are limited and are similar to most resource- limited countries.
No routine program has been put in place in Georgia to screen HCWs for latent tuber- culosis infection (LTBI) at the NTP or other health care facilities.1,2,10 Until recently, the tuberculin skin test (TST), which has been available for more than 100 years, was the only test available for the diagnosis of LTBI.
The TST measures a delayed-type hypersensitivity response to puriﬁed protein derivative (PPD), a mixture of anti- gens shared among M. tuberculosis, bacille Calmette- Guérin (BCG) and several non-tuberculous mycobac- teria (NTM).12 Limitations of the TST include problems with false-positive (due to cross-reactions with BCG and NTM) and false-negative test results (e.g., due to anergy).
Moreover, the test requires two trips to a health care provider, one for placement and a second 48–72 h later to have the results read.12,13 A new gen- eration of diagnostic tests for LTBI, the interferon- gamma release assays (IGRAs) have recently become available.4 The whole-blood IGRA, QuantiFERON®- TB Gold, has been approved by the US Food and Drug Administration (FDA) for use in the US, and the CDC has published guidelines on its use.4 A newer version of this test, the QuantiFERON®-TB Gold In Tube (QFT-3G) test, which is logistically easier to use, is now FDA-approved and also available for use in a number of countries.
The QFT-3G uses antigens that are more speciﬁc to M. tuberculosis and not found in BCG, and most NTM.

Unlike the TST, IGRAs require a single patient visit, do not boost amnestic immune re- sponses, eliminate the subjectivity of the TST reading and can be completed in less than 24 h. A limited number of studies evaluating the perfor- mance of IGRAs have been conducted in TB-endemic settings.

Few studies have examined the use of these tests in HCWs.
The purpose of the present study was to assess the prevalence and risk factors for LTBI among Georgian HCWs working for the NTP and af- ﬁliated institutions.

It was important to obtain these * Salakaia A. TB epidemiology in Georgia: achievements and chal- lenges.

Unpublished presentation at a US-Caucasus workshop on operational research in HIV and TB, October 25, 2005.

Tbilisi, Georgia; 2005.


Lomtadze N. High rates of multidrug resistant tuber- culosis in the country of Georgia: a population based study.

Unpub- lished presentation at 11th Annual Meeting North American Region of the International Union Against Tuberculosis and Lung Disease, Vancouver, BC, Canada, 2007. data prior to the planned implementation of TB infec- tion control measures in Georgia as part of the NTP 5-year (2007–2011) TB Control Plan.
LTBI was as- sessed using both standard (TST) and new (QFT-3G) diagnostic tests.

Concordance between the two diag- nostic tests was also assessed.

STUDY POPULATION AND METHODS Participants and data collection We conducted a cross-sectional study from June to August 2006 at the National Center for Tuberculosis and Lung Diseases (NCTLD)/NTP and afﬁliated insti- tutions in Georgia.
All HCWs, including physicians, nurses, orderlies, housekeepers, laboratory workers and administrative staff from 75 health care facilities that were part of the NTP or afﬁliated sites, were eli- gible for enrollment into the study.

All HCWs enrolled were required to provide written informed consent in their native Georgian language of Kartuli.

The study was approved by the Ethics Committee of the NCTLD and the Emory University Institutional Review Board.
Each HCW enrolled into the study completed a questionnaire containing data on age, sex, country of birth and ethnicity, education, number of years em- ployed as an HCW, occupation, prior TST history, history of BCG vaccination and history of active TB.

BCG status was also assessed by visual inspection for a BCG scar.

Information on possible community ex- posure to TB was also collected, including household contacts with TB.
HCWs were considered to have high occupational exposure to TB if they routinely had direct contact with infectious TB patients (e.g., on a daily basis) during the course of their duties.

HCWs who worked in the NTP administration building and had no routine patient contact and HCWs at the In- fectious Diseases, AIDS and Clinical Immunology Re- search Center were considered to have limited occu- pational exposure to TB.
After 3 ml of blood was drawn for the IGRA, a TST was placed using 5 tuberculin units (TU) of PPD (Tubersol, Connaught; Swiftwater, PA, USA).

TST was performed using the Mantoux method13 and read 48– 72 h after placement.
Based on published guidelines, an induration of 10 mm was considered a positive TST in HCWs.13,14 Participants who had a positive TST or a positive QFT-3G (as deﬁned below) were advised to have a chest radiograph performed (at no cost to them) at an NTP facility and were referred to a phy- sician at the NCTLD for further evaluation and con- sideration for treatment of LTBI.

There were no costs incurred for HCWs who participated in the study.
Laboratory methods The QFT3-G test (Cellestis, Carnegie, VIC, Australia) was performed according to the manufacturer’s rec- ommendations and as previously described.15,16 The QFT-3G assay uses more speciﬁc antigens for M. tuber- culosis to test for LTBI, including the early secreted antigenic target 6 (ESAT-6), culture ﬁltrate protein 10 (CFP-10) and TB antigen TB7.7 (Rv2654).
As recom- mended by the manufacturer and based on previous studies,15 a positive QFT-3G was deﬁned as interferon- gamma (IFN-) 0.35 international units (IU)/ml if the response to TB antigens minus the negative control was 0.35 IU/ml and 25% of the negative control, neg- ative if these criteria were not met, and indeterminate if either the negative control had a result of 8 IU/ml or if the positive control had a result of 0.5 IU/ml.
Be- cause the QFT-3G enzyme-linked immunosorbent assay cannot accurately measure absolute IFN- values 10 IU/ml, such values were treated as 10 IU/ml.15 Statistical analysis Data were entered into Epi Info version 3.3.2 (CDC, Atlanta, GA, USA).

Statistical analyses were per- formed using SAS software version 9.1 (SAS Institute Inc., Cary, NC, USA).
Concordance between the two diagnostic tests for LTBI (TST and QFT-3G) was measured using the kappa () statistic, where 0.75 represents excellent agreement, 0.4–0.75 fair to good agreement and 0.4 represents poor agreement, beyond chance.17 Correlation between continuous IFN- values (in IU/ml) and TST indura- tion (in mm) was assessed using Spearman’s correla- tion coefﬁcient.18 Risk factors for a positive LTBI test result (TST or QFT-3G) were evaluated using preva- lence odds ratios (PORs).
To adjust for multiple cova- riates, we used a logistic regression method.

Variables included in the ﬁnal multivariate model were chosen a priori on the basis of the biological plausibility of their association with the outcome of interest, as well as on the basis of statistical and epidemiological cri- teria.

A P value 0.05 was deﬁned as statistically sig- niﬁcant.

A single ‘chunk’ test19 was performed to as- sess the signiﬁcance of all the interaction terms.
The statistical signiﬁcance of the ‘chunk’ test was ad- dressed using the unconditional maximal likelihood ratio test.19,20 RESULTS Participant description Of the 1231 HCWs employed at the 75 Georgian NTP and afﬁliated sites, 281 were enrolled in the study.

Sixteen were excluded from the ﬁnal analysis: 10 par- ticipants had a previous history of active TB disease, one HCW refused to have blood drawn and ﬁve others were excluded because they did not return to have their TST read.
Data were analyzed for 265 Georgian HCWs.

The mean age was 42 years (range 18–74); 229 (86%) were women (reﬂecting the sex distribution of HCWs at the NTP) and 244 (92%) had been BCG- vaccinated.

The median length of employment as an LTBI among Georgian HCWs 515 HCW at the NTP or afﬁliated institutions was 8 years (range 1–42).

Of the 265 study subjects, 215 (81%) had routine (e.g., daily) contact with infectious TB patients cared for by the Georgian NTP.
Demo- graphic information of HCWs enrolled into the study is presented in Table 1.

The demographics of those enrolled reﬂect those of the overall HCW population at the NTP and afﬁliated sites.

Diagnostic tests for LTBI Overall, 203 (76.6%) of the 265 HCWs had a posi- tive test result for at least one of the diagnostic tests for LTBI.
A total of 177 (66.8%) had a positive TST (95% conﬁdence interval [CI] 60.8–72.4) using a cut-off point of 10 mm induration and 159 (60.0%) had a positive QFT-3G test result (95%CI 53.8–65.9).

One hundred and thirty-three (50%) HCWs had pos- itive results for both diagnostic tests, 62 (23%) were negative for both tests, 44 (17%) had a positive TST but a negative QFT-3G, and 26 (10%) had a positive QFT-3G and negative TST (Table 2).
Absolute values for IFN- concentration and TST induration are pre- sented in the Figure.

There was moderately good agree- ment between the two tests (74%, 0.434, 95%CI 0.326–0.545) (Table 3).
Changing the TST cut-off points (i.e., using 5 mm and 15 mm of induration in- stead of 10 mm) did not greatly impact concordance Table 1 Demographic information of health care workers (n 265) Characteristic Age, years 18–30 31–40 40 Sex Female Male Education level College graduate Some college Secondary school and under Occupation Administrative staff Physicians Nurses Other Length of employment as HCW, years 1 2–5 6–10 10 Frequent (daily) contact with TB patents* Positive history of BCG vaccination† n (%) 45 (17.0) 65 (24.5) 155 (58.5) 229 (86.4) 36 (13.6) 121 (45.7) 111 (41.9) 33 (12.5) 29 (11.0) 60 (22.6) 87 (32.8) 93 (33.6) 32 (12.1) 76 (28.7) 53 (20.0) 104 (39.3) 215 (81.1) 206 (77.7) * Deﬁned as working in buildings where TB patients undergo TB diagnosis and treatment on a daily basis (excludes HCWs from the NTP administrative building and HCWs from the Infectious Diseases, AIDS and Clinical Immunol- ogy Research Center).
† Unknown history of BCG vaccination is classiﬁed as a negative history of BCG vaccination.

HCW health care worker; TB tuberculosis; BCG bacille Calmette- Guérin; NTP National Tuberculosis Program; AIDS acquired immune- deﬁciency syndrome.
516 The International Journal of Tuberculosis and Lung Disease Table 2 Prevalence of latent tuberculosis infection among Georgian health care workers (n 265) Table 3 Concordance between TST and QFT-3G results Results* Positive TST Positive QFT-3G test Positive TST and/or QFT-3G test Positive TST and QFT-3G tests Positive TST/negative QFT-3G test Negative QFT-3G/positive TST Positive cases n (%) TST/QFT-3G results* 177 (66.8) 159 (60.0) 203 (77.0) 133 (50.0) 44 (17.0) 26 (10.0) Negative/negative Positive/positive Positive/negative Negative/positive Agreement, % 95%CI 5 mm 44 (16.6) 150 (56.6) 62 (23.4) 9 (3.4) 73.2 TST cut-off point 10 mm 62 (23.4) 133 (50.2) 44 (16.6) 26 (9.8) 73.6 15 mm 76 (28.7) 110 (41.6) 30 (11.3) 49 (18.5) 70.3 0.39 0.29–0.50 0.43 0.33–0.55 0.40 0.29–0.51 * TST cut-off point 10 mm.
TST tuberculin skin test; QFT-3G test QuantiFERON®-TB Gold in Tube test.

between the TST and QFT-3G (Table 3).

There was a signiﬁcant correlation between absolute values of TST and QFT-3G when assessed using Spearman’s correlation coefﬁcient ( 0.52, P 0.001).
In univariate analysis, age 30 years and length of employment as a HCW for 5 years at the NTP were signiﬁcantly associated with having a positive TST re- sult; age 30 years, female sex, direct exposure to in- fectious patients with TB, and length of employment as a HCW 5 years was associated with increased risk of having a positive QFT-3G test (Table 4).
In multi- variate analysis, length of employment as a HCW for 5 years (odds ratio [OR] 5.09, 95%CI 2.77–9.33) was independently associated with increased risk of a positive TST result, while age 30 years (OR 2.91, 95%CI 1.32–6.43) and length of employment as an HCW 5 years (OR 2.26, 95%CI 1.27–4.01) were independently associated with increased risk of a hav- ing a positive QFT-3G result (Table 5).
DISCUSSION We found the prevalence of LTBI among Georgian HCWs at the NTP and afﬁliated institutions to be higher than in the previous two reports using IGRAs for evaluation of LTBI among HCWs in resource- * QFT-3G cut-off point 0.35 IU/ml.

TST tuberculin skin test; QFT-3G QuantiFERON®-TB Gold in Tube test; CI conﬁdence interval.
limited countries.21,22 Overall, 77% had a positive test result for at least one of the LTBI diagnostic tests: 66.8% had a positive TST and 60% had a positive QFT-3G.

In multivariate analysis, employment as an HCW for 5 years was associated with an increased risk of a positive TST (OR 5.09) or QFT-3G (OR 2.26).

In addition, age 30 years was associated with an increased risk of a positive QFT-3G test (OR 2.91).
Our ﬁndings are consistent with other reports that increasing age and more years of work in health care are associated with higher prevalence of LTBI.23 However, very few studies have reported the use of IGRAs in the evaluation of HCWs in resource-limited countries.

The higher prevalence of LTBI found in our study compared to the two previous reports21,22 could be due to the fact that our study population contained HCWs particularly involved in TB control.
In Georgia, patients with TB are diagnosed and treated in specialized TB facilities organized by the Georgian NTP, and generally do not receive care in other health care facilities.

The high rate of LTBI among Georgian HCWs likely reﬂects ongoing expo- sure to infectious TB patients in hospitals that have had limited or no TB infection control measures.
The risk of testing positive for LTBI (by either diagnostic test) Figure Distribution of A) TST induration and B) IFN- release assay responses (n 265).

TST tuberculin skin test; IFN- interferon- gamma; IU international units.
LTBI among Georgian HCWs 517 Table 4 Risk factors associated with a positive latent tuberculosis infection diagnostic test among HCWs in Georgia: a univariate analysis Variable Age, years 30 30 Female Education level Graduate Some college education Secondary school or under Occupation Hospital administrative staff Physician Nurse Other Length of employment as HCW, years 5 5 TST* QFT-3G test† Positive tests/total tested n (%) Unadjusted OR (95%CI) Positive tests/total tested n (%) Unadjusted OR (95%CI) 21/45 (46.6) 156/220 (70.1) 1.00 2.79 (1.45–5.36)‡ 13/45 (28.9) 146/220 (66.3) 1.00 4.86 (2.41–9.81)‡ 156/229 (68.1) 1.53 (0.74–3.13) 144/229 (66.4) 2.37 (1.16–4.85)‡ 81/121 (45.2) 72/111 (64.9) 25/33 (75.8) 1.00 1.60 (0.66–3.86) 0.95 (0.55–1.63) 65/221 (53.7) 70/111 (63.0) 24/33 (72.7) 1.00 1.47 (0.87–2.49) 2.30 (0.99–5.35) 19/29 (65.5) 40/60 (66.7) 59/87 (67.8) 59/93 (63.4) 1.00 1.05 (0.41–2.68) 1.11 (0.46–2.70) 1.04 (0.43–2.50) 11/29 (37.9) 36/60 (60.0) 56/87 (64.4) 56/93 (60.2) 1.00 2.45 (0.99–6.10) 2.96 (1.24–7.05)‡ 2.78 (1.17–6.59)‡ 49/108 (45.4) 128/157 (81.5) 1.00 5.32 (3.06–9.24)‡ 47/108 (43.5) 112/157 (71.3) 1.00 3.23 (1.93–5.40)‡ Has routine direct contact with TB patients§ 149/215 (69.3) 1.77 (0.95–3.33) 140/215 (65.7) 3.05 (1.61–5.75)‡ Positive history of BCG vaccination¶ 162/206 (78.6) 0.79 (0.30–2.12) 142/206 (68.9) 0.33 (0.11–1.00) * TST induration cut-off point 10 mm.
† QFT-3G test cut-off point 0.35 IU/ml.

‡ Statistically signiﬁcant.

§ Deﬁned as working in buildings where TB patients undergo TB diagnosis and treatment on a daily basis (excludes HCWs from the NTP administrative building and HCWs from the Infectious Diseases, AIDS and Clinical Immunology Research Center).

¶ Unknown history of BCG vaccination is classiﬁed as a negative history of BCG vaccination.
HCW health care worker; TST tuberculin skin test; QFT-3G test QuantiFERON®-TB Gold in Tube test; OR prevalence odds ratio; CI conﬁdence interval; BCG bacille Calmette-Guérin; TB tuberculosis; IU international unit; NTP National TB Program; AIDS acquired immune-deﬁciency syndrome.
Table 5 Risk factors associated with a positive latent tuberculosis infection diagnostic test among HCWs in Georgia: multivariate analysis Covariate Age 30 years Female Occupation Administrative staff Physicians Nurses Other Employment as HCW 5 years TST* Adjusted OR† (95%CI) QFT-3G test‡ Adjusted OR† (95%CI) 1.17 (0.54–2.53) 2.91 (1.32–6.43) 1.30 (0.56–3.03) 1.78 (0.78–4.08) 1.00 0.30 (0.08–1.15) 0.31 (0.07–1.34) 0.29 (0.08–1.10) 1.00 0.82 (0.22–3.11) 1.07 (0.25–4.59) 0.97 (0.25–3.66) 5.09 (2.77–9.33) 2.26 (1.27–4.01) Has routine direct contact with TB patients§ 2.32 (0.80–6.71) 2.06 (0.71–5.98) Positive history of BCG vaccination¶ 0.74 (0.25–2.23) 0.26 (0.07–0.91) * TST induration cut-off point 10 mm.
† A multivariable logistic regression model includes age, sex, occupation, length of employment as HCW, daily contact with TB patients and history of BCG vaccination.

‡ QFT-3G test cut-off point 0.35 IU/ml.

§ Deﬁned as working in buildings where TB patients undergo diagnosis and treatment on a daily basis (excludes HCWs from the NTP administrative build- ing and HCWs from the Infectious Diseases, AIDS and Clinical Immunology Research Center).
¶ Unknown history of BCG vaccination is classiﬁed as a negative history of BCG vaccination.

HCW health care worker; TST tuberculin skin test; QFT-3G test QuantiFERON®-TB Gold in Tube test; OR odds ratio; CI conﬁdence inter- val; TB tuberculosis; BCG bacille Calmette-Guérin; IU international unit; NTP National Tuberculosis Program; AIDS acquired immune-deﬁciency syndrome.
increased with increasing length of time (i.e., 5 years) of employment as an HCW at the Georgian NTP.

The WHO has proposed interventions to reduce nosocomial transmission in settings where resources are limited.8,9 These recommendations emphasize ad- ministrative controls, including careful screening and prompt diagnosis of TB, separation of TB patients and TB suspects from other patients and rapid treat- ment of TB.
However, compliance with these TB in- fection control guidelines is generally poor in low- income countries.15 The importance of TB infection control measures is gaining increasing attention due to reports of XDR-TB, which is associated with high rates of morbidity and mortality,11 especially among immunocompromised persons such as those with HIV infection.

Nosocomial transmission appears to play an important role in amplifying XDR-TB transmission.
Given the frequent exposure to infectious TB pa- tients, it is not surprising that we found high rates of LTBI (using both the TST and QFT-3G test) among Georgian HCWs at the NTP and afﬁliated sites.

The prevalence of LTBI in the general population in Georgia is not known, as no surveys for LTBI have been carried out.

However, we suspect that rates of LTBI are much higher among HCWs at the Georgian NTP than others in the population, including other high-risk groups.
For example, a previous study of LTBI using TST among internally displaced persons (IDPs) in Georgia found a prevalence of 48% among 988 IDPs.24 518 The International Journal of Tuberculosis and Lung Disease A systematic review of TB among HCWs in low- and middle-income countries reported a prevalence of LTBI of 54% (range 33–79) using the TST.2 Our ﬁnd- ings of a positive TST were at the higher end of this range, likely reﬂecting frequent exposure to infec- tious TB cases.
We are aware of only two prior cross- sectional studies that have assessed the use of new IGRA diagnostics tests for LTBI such as the QFT-3G among HCWs.

One was reported from Samara, Rus- sia21 and the other from India.22 Both noted an LTBI prevalence of about 40% using the QFT-3G.

These studies included HCWs who did not provide care for TB patients.

We focused on HCWs at the Georgian NTP who exclusively cared for patients with TB; this may explain the higher prevalence in our study.
There was moderate concordance between the TST and the QFT-3G test in our study (agreement of 74%, 0.43).

In a study of HCWs in India, the agreement between the tests was higher (81%, 0.61).
The use of 1 TU PPD RT23 in the study from India may have improved TST speciﬁcity and could have been a reason for the observed higher agree- ment.23 In the case of our study, the observed moder- ate or fair agreement between the diagnostic tests for LTBI might be explained by the high prevalence of TB infection and the high BCG vaccination coverage in the study participants.

There are several limitations to our study.


First, be- cause testing for LTBI is not routinely performed in Georgia, participation in our study was voluntary and did not include all HCWs at the Georgia NTP and afﬁliated sites.

Using a convenience sampling method, we enrolled approximately 23% of the eligible popu- lation, with enrollment taking place at eight of a pos- sible 75 eligible facilities.
The TB facilities at which pa- tients were enrolled were diverse in nature and included hospitals, administration ofﬁces, TB clinics and labo- ratory facilities, and were geographically widely spread throughout the country.

We tended to choose larger facilities, and there was a 75% participation rate at the facilities where HCWs were enrolled.

The demo- graphics of those HCWs enrolled in the study were similar to those of the entire HCW population at the NTP.
Although we collected data on BCG vaccination status, we did not collect information about the num- ber of BCG vaccinations.

During the Soviet era, it was not unusual for HCWs and others to receive multiple doses of BCG.

Since Georgia became independent in the early 1990s, BCG vaccination has been given only to infants.
The number of BCG vaccinations may be important, as data suggest that those with BCG vac- cination after infancy produce more frequent, more persistent and larger TST reactions.25 CONCLUSIONS We found high LTBI rates among HCWs at the Geor- gian NTP using both TST and IGRA.

The IGRA was well accepted by HCWs in this study.

Our study pro- vides important baseline information on the preva- lence of LTBI among Georgian HCWs involved in TB control.
Obtaining baseline information and estab- lishing surveillance for LTBI among Georgian HCWs is important, as one of the priorities of TB control in Georgia for the next 5 years is the implementation of effective TB infection control measures.
Further re- search is needed to assess the utility of longitudinal IGRA use among HCWs, how to implement and gain acceptance from HCWs for treatment of LTBI among high risk HCWs and how best to implement TB infec- tion control measures to protect the health and safety of HCWs and patients in Georgia.

Acknowledgement This study was supported in part by funding from the National Institutes of Health/Fogarty International Center [D43 TW007124 and D43 TW01042].
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R É S U M É C O N T E X T E : La tuberculose (TB) constitue un problème majeur de santé publique en Géorgie, mais peu de mesures de lutte contre l’infection tuberculeuse ont été mises en œuvre dans les services de soins de santé.
O B J E C T I F : Evaluer la prévalence et les facteurs de risqué d’infection tuberculeuse latente (LTBI) chez les tra- vailleurs de soins de santé (HCW) de Géorgie en utilisant deux tests de diagnostic, le test cutané tuberculinique (TST) et le test QuantiFERON®-TB en tube (QFT-3G), un test de libération de l’interféron-gamma.

M É T H O D E S : On a mené, entre juin et août 2006, une étude transversale parmi les HCW dans le Programme National Géorgien de Lutte contre la Tuberculose.
R É S U L T A T S : On a enrôlé dans l’étude 265 HCW ; chez 177 (67%) le TST était positif et chez 159 (60%) le test QFT-3G était positif.

Un résultat positif a été obtenu pour au moins un des tests chez 203 sujets (77%) et une réponse positive pour les deux tests chez 50%.

La con- cordance est modérément bonne entre les tests (74% ; 0,43 ; IC95% 0,33–0,55).
Lors de l’analyse multivariée, on a trouvé que le fait d’avoir un emploi depuis 5 ans est en association avec un risque accru de TST positif (OR 5,09 ; IC95% 2,77–9,33) et d’un test positif QFT- 3G (OR 2,26 ; IC95% 1,27–4,01) ; un âge 30 ans est associé à un risque accru de QFT-3G positif (OR 2,91 ; IC95% 1,32–6,43).

D I S C U S S I O N : Chez les HCW de Géorgie, on a trouvé une prévalence élevée de la LTBI et l’association d’une durée plus longue de travail avec un accroissement du risque.
Ces données éclairent la nécessité de mesures ef- ficientes de lutte contre l’infection tuberculeuse et con- stituent une information de base importante pour la mise en oeuvre de mesures de contrôle de l’infection tuberculeuse.

M A R C O D E R E F E R E N C I A : Pese a que la tuberculosis (TB) constituye un importante problema de salud pública en Georgia, pocas han sido las medidas de control de la infección tuberculosa introducidas en los establecimien- tos de atención de salud.
O B J E T I V O : Evaluar la prevalencia y los factores de riesgo de infección tuberculosa latente (LTBI) en los profesionales de la salud (HCW) en Georgia mediante dos pruebas diagnósticas, la reacción cutánea a la tuber- culina (TST) y una prueba de liberación de interferón- gama, el QuantiFERON®-TB en tubo (QFT-3G).

M É T O D O : Estudio transversal llevado a cabo entre junio y agosto de 2006 en HCW del Programa Nacional de Tuberculosis de Georgia.
R E S U L T A D O S : Participaron en el estudio 265 HCW ; 177 (67%) presentaron una reacción positiva a la TST y 159 (60%) una prueba QFT-3G positiva.

Doscientos tres participantes (77%) tuvieron un resultado positivo R E S U M E N por lo menos a una de las pruebas y en 50% ambas prue- bas fueron positivas.

Se observó una concordancia mode- radamente buena entre ambas pruebas (74%, índice 0,43 ; IC95% 0,33–0,55).
En el análisis multifacto- rial se encontró que una permanencia en el trabajo du- rante 5 años se asociaba con una mayor probabilidad de reacción positiva a la TST (OR 5,09 ; IC95% 2,77– 9,33) y a la prueba QFT-3G (OR 2,26 ; IC95% 1,27–4,01) ; la edad 30 años se asoció con un riesgo aumentado de una prueba QFT-3G positiva (OR 2,91 ; IC95% 1,32–6,43).
D I S C U S I Ó N : Se encontró una alta prevalencia de LTBI en los HCW de Georgia y la mayor permanencia en este empleo se asoció con un mayor riesgo.

Estos datos ponen de manifiesto la necesidad de medidas eficaces de control de la infección tuberculosa y aportan una impor- tante información de referencia para el momento en que se instauren dichas medidas.