This study confirms the usefulness of fine-needle aspiration for investigating patients with suspected tuberculous lymphadenitis before starting anti-TB therapy. Microscopy showed the presence of potential TB bacilli in 42.7% of the aspirates, and culture identified TB in 67.2% of cases. The percentage of Ziehl-Neelsen-positive strains was much higher than the 18% observed by Knox
 but close to those reported recently (45%
 and 48.2–51.8%
) with light-emitting diode microscopy in studies of mycobacterial lymphadenitis in fine-needle aspirates from children. The conventional Ziehl-Neelsen method on smears is widely used and plays a key role in TB diagnosis, but it has a poor sensitivity in aspirates because of the small number of mycobacterial cells. Löwenstein-Jensen culture showed that 88 (67.2%) samples were positive, confirming the greater sensitivity of culture than Ziehl-Neelsen staining, and in agreement with recent reports of culture sensitivity of 65.8%
 and 86.4%
Our finding that 83.3% of smear-positive culture-negative specimens were from patients who had received anti-TB treatment suggests that positive acid-fast bacilli results might correspond to dead bacilli from previously treated patients. This confirms the need to perform bacteriological diagnosis before treatment. Mycobacterial culture is the gold standard for detecting tubercle bacilli, although it is time-consuming and requires specialized technology and procedures in a biosafety facility.
The study confirmed that the overall drug resistance rate is close to that reported in CAR between 1998 and 2000
 and is lower than the rate published by Koeck et al.
 in Djibouti. Resistance to isoniazid and streptomycin was most frequent in children with undiagnosed TB, which confirms our previous findings in adults
. In CAR, these drugs are improperly used for the treatment of other bacterial infections, which can lead to resistance.
In general, biopsy is the preferred method for obtaining a sample for testing. In most of sub-Saharan Africa, however, due to a lack of facilities and manpower, it is feasible for only very few patients. Lymph node aspirates are simple to obtain, and the procedure is cheap and safe with limited risks, as it is less invasive and requires minimal instrumentation. This technique is especially suitable for peripheral lymph nodes and can be performed by trained nurses in small hospitals and clinics.
Recent advances in molecular diagnosis will affect future TB diagnostic approaches. Detection of mycobacterial DNA and rifampicin resistance with nucleic acid-based methods can be helpful in the diagnosis of tuberculous lymphadenatis. Combining fine-needle aspiration, which can be performed on an outpatient basis in a primary health care setting, with a rapid, sensitive diagnostic technique such as those based on nucleic acids may contribute substantially to the effective management of mycobacterial infection in children
[19, 20]. The implications of rapid, accurate diagnosis include access to appropriate, adequate therapy and less costly further investigations. The fully automated real-time polymerase chain reaction-based GeneXpert MTB/RIF test allows rapid, highly sensitive detection of M. tuberculosis complex DNA and of mutation-mediating rifampicin resistance
, and WHO recently endorsed this new diagnostic test
. When used on lymph node tissue, the reported sensitivity for bacterial diagnosis was 86%
 to 96%
. This new test and other, more effective, less costly tests being developed will strengthen rapid diagnosis from fine-needle aspirates. Rational use of fine-needle aspiration followed by immediate empiric therapy is the optimal approach. Although the GeneXpert MTB/RIF test may be useful for rapid detection of TB in lymph node aspirates and can indicate multidrug-resistant TB in cases of rifampicin resistance, it cannot, however, replace other tests for precise identification of other antibiotic resistance or confirm rifampicin resistance.