Clinical, molecular and drug sensitivity pattern of mycobacterial isolates from extra-pulmonary tuberculosis cases in Addis Ababa, Ethiopia.
BACKGROUND
In conjunction with the spread of HIV infection, tuberculosis (TB) remains a major cause of illness and death worldwide. The Ethiopian national report reveals that extra pulmonary tuberculosis is on the rise and that case detection rate is exceeding that of smear positive or negative cases in many parts of the country. Different studies indicated that host and/or pathogen related factors are associated with the rise of extra pulmonary cases. However, the reason for this is not clearly known in our setting.


METHODS
Specimens were taken from clinically suspected extra pulmonary patients and confirmed by cytology, histopathology and culture. Deletion typing and Spoligotyping was utilized to identify the strains. The isolates were then assigned to lineage using conformal Bayesian network (rules model) algorithm and dendrograms were drawn using UPGMA methods. In addition, drug sensitivity test was done using the indirect proportion and 24 well plate methods.


RESULTS
Out of the 200 clinically suspected extra pulmonary tuberculosis patients, 106 (53 %) were between 15 and 35 years of age and 167 (83.5 %) were new while 33 (16.5 %) were retreatment cases. The culture yield was 29.5 % (59). Of these only one was M. bovis and 58 were M. tuberculosis strains with 31 different spoligotype patterns grouped into seven clusters. The largest cluster (ST53) comprised 12 (20.3 %) isolates. There was higher clustering of CAS isolates in TBLN than in any other form of extra pulmonary tuberculosis cases. Resistance to rifampicin was higher (22 %) than that for INH, STM and EMB (8.1 %, 5 % and 3 % respectively). Out of the 37 isolates tested for resistance, only 2 isolates were resistant for both STM and INH and no MDR strain was found.


CONCLUSIONS
There is an ongoing active recent transmission among extra pulmonary tuberculosis in the study areas as shown by the presence of clusters. Although no MDR case was observed, there is a risk of emergence of MDR as noted from the high proportion of resistance to rifampicin. Detailed study at population level is recommended to monitor its trend.
Institute of Biotechnology, Addis Ababa University, P.O. Box 62720, Addis Ababa, Ethiopia. Workneh.korma@aau.edu.et.|Armauer Hansen Research Institute, P.O.Box 1105, Addis Ababa, Ethiopia. Workneh.korma@aau.edu.et.
Workneh
W
Korma
Armauer Hansen Research Institute, P.O.Box 1105, Addis Ababa, Ethiopia. Adane_mihret@yahoo.com.
Adane
A
Mihret
Armauer Hansen Research Institute, P.O.Box 1105, Addis Ababa, Ethiopia. jemaldr@gmail.com.
Jemal
J
Hussien
Royal Tropical Institute, Meibergdreef 39, 1105 AZ, Amsterdam, The Netherlands. r.anthony@kit.nl.
Richard
R
Anthony
Department of Microbial, Cellular and Molecular, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia. Yibza2002@yahoo.com.
Mekuria
M
Lakew
Armauer Hansen Research Institute, P.O.Box 1105, Addis Ababa, Ethiopia. aseffaa@gmail.com.
Abraham
A
Aseffa
D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000188:drug therapy; D024881:Drug Resistance, Bacterial; D005002:Ethiopia; D005260:Female; D015658:HIV Infections / Q000175:diagnosis / Q000188:drug therapy / Q000382:microbiology; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification*; D019233:Retreatment; D012293:Rifampin / Q000627:therapeutic use; D019966:Substance-Related Disorders / Q000188:drug therapy; D014376:Tuberculosis / Q000188:drug therapy / Q000382:microbiology*; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis; D055815:Young Adult
D000995:Antitubercular Agents; D012293:Rifampin