Comparative Study Between Using Lowenstein Jensen And Bio-fm Medial In Identification Of Mycobacterium Tuberculosis:

Mohamed Gaml Akl Ali

Tuberculosis (T.B.) still represents a monumental problem in the world, withalmost 9.4 (range 8.9-9.9 million) million new cases in 2008(139 per 100 000population) compared with 9.27 million new cases (139 per 100 000 population) in2007 and 9.24 million new cases (140 per 100 000 population) in 2006.Although smear microscopy shows the highest rates of disease detectionyearly world wide, culture systems give more accurate results for isolation of MTBas they are more sensitive than smear microscopy. Lowenstein Jensen culture is themost widely used especially in low-income countries, On the other hand, Bio-FMis an enriched Middlebrook 7H9 medium, optimized for rapid MTB growth.This work aimed to evaluate the detection rate and time of MTB by usingBio FM system in comparison with the Lowenstein-Jensen medium.This study included 50 sputum smear positive tuberculous patients, whowere classified into 34 new cases (group I) representing 68% of the total cases, 10relapsed cases (group II) and 6 treatment failure cases (group III) representing20% and 12% of the total cases respectively.The following were done to all cases1- Thorough history taking2-Complete physical examination3-Routine laboratory tests including ESR4-Plain chest X-ray P.A and lateral view when needed5-Sputum smear for acid fast bacilli (Zeil Neelsen staining)6-Tuberculin skin test using Mantoux technique7- Sputum culturing on Lowenstein-Jensen medium8- Sputum culturing on Bio -FM medium9-The results were tabulated and statistically analyzed.Summary90The mean age in group I was 39.47 years ±15.122 and in group II 41.60years ±11.983 while in group III it was 37.50 years ±12.518. It was noticed that allgroups were age matched and there were no statistical differences between them.In group I: male patients were 26 (76.47%) and female were 8 (23.53%), while ingroup II: male patients were 8 (80%) and female were 2(20 %). In group III: 5male (83.33%) and only one female (16.67%) were in this group. It was noticedthat all groups were sex matched and there were no statistical differences betweenthem.These result showed that the highest value of mean ESR was (68.97mm/hour ± 24.677) concerned with group I in which 31 patients gave positivereactions (91.18%), compared with the lowest value which was (29.20 mm/hour ±22.295) concerned with group II, with 8 patients gave positive reactions in thisgroup. In group III, 5 patients gave positive reactions and the mean value was(36.50 mm/hour ± 31.227).Tuberculin test gave significant induration only in 44 cases (88%) of total50 cases, 31 in group I (91.18%), 8 in group II (80%) and 5 in group III(83.33%).The highest mean value was for the cases of group I (16.13 mm ± 4.717)and the lowest was for group III (9.80 mm ± 3.563) with group II (11mm ± 5.043)in between, while the total cases record (14.46 mm ± 5.298). The highest value fora single case was 24 mm in group I and the lowest was 5 mm for 2 cases in groupII.14 patients with minimal lesion on chest X- ray gave positive results onLowenstein Jensen compared with only 13 on Bio-FM. 21 patients with moderateadvanced gave positive results on Lowenstein Jensen compared with only 20 onBio-FM. 12 patients with far advanced lesion gave positive results on both media.The mean detection time on Bio-FM was significantly shorter than that onLowenstein Jensen in cases of moderately advanced tuberculous lesions on chestSummary91X-ray (P-value < 0.05), while in cases with minimal and far advanced radiologicallesion, it was highly significant (P-value < 0.001).Thirteen patients with cavitary lesion on chest X- ray gave positive resultson both media 34 patients without cavitary lesion gave positive results onLowenstein Jensen compared with only 33 on Bio-FM.The mean detection time on both media in cases with cavitary lesion onchest X-ray was highly significantly shorter than these cases without cavitarylesions (P-value < 0.001). The mean detection time on Lowenstein Jensen for caseswith cavitary lesions was (14.39 days ±1.938) compared with that for cases withnon cavitary lesion which was (22.65 days ±10.259) and on Bio-FM was (7.62days ± 2.219) for cases with cavitary lesion and (14.36 days ± 9.384) for cases withnon cavitary lesion.Risk factors for TB such as DM, COPD, CRF or long term treatment such ascorticosteroid or chemotherapy, have lowered the mean detection times of patientshaving one of them than that of patients have nothing beside TB, that on eithermedia from one side and on Bio-FM compared with Lowenstein Jensen on theother side. These risk factors also signified the shorter mean detection times onBio-FM (P-value < 0.05 or less) compared with these on Lowenstein Jensen.On the other hand, patients with no risk factors for TB show insignificantshorter mean detection times on Bio-FM than that on Lowenstein Jensen (P-value>0.05).In this study, we compare between both media as regard duration range. Nocases gave positive results on Lowenstein Jensen with duration up to 7 dayscompared with 14 cases gave positive results on Bio-FM representing 30.43% ofthe total number of cases. On the other hand, with duration range 8-14 days, 15cases gave positive results on Lowenstein Jensen representing 31.91% of the totalnumber of cases compared with 20 cases on Bio-FM representing 43.48% of theSummary92total cases. The total number of cases that gave positive results on Bio-FM withduration range up to 14 days was 34 cases representing 73.91% compared with 15cases on Lowenstein Jensen representing only 31.91% of the total number of cases.With duration range 14-21 days, 19 cases gave positive results onLowenstein Jensen representing 40.43% % of the total number of cases comparedwith 7 cases on Bio-FM representing 15.23% of the total number of cases.With duration range beyond 14 days up to 56 days, only 5 cases gavepositive results on Bio-FM representing 10.86% % of the total number of casescompared with 13 cases Lowenstein Jensen on representing 27.65% of the totalnumber of cases. It is noted that no cases gave positive results on Bio-FM after 49days.All cases of group I gave positive results on Lowenstein Jensen (100%)compared with only 33 cases of this group gave positive results on Bio-FM(97.1%). Only 8 cases in group II gave positive results on both media (80%) and 5cases in group III (83.33%).The main purpose of this study is to compare between Lowenstein Jensenand Bio-FM as regard detection time and rates. No significant difference betweenthe two media in diagnostic yeild (94% of the total cases give positive results onLowenstein Jensen compared with 92% on Bio-FM), but the detection time ofcases on Bio-FM was highly significant shorter than that of cases on LowensteinJensen (P-value < 0.001).Conclusion & recommendation93ConclusionComparison between Lowenstein Jensen and Bio-FM as regard detectionrate and time in this study shows great superiority of Bio-FM over LowensteinJensen in detection time with no significant difference between two media indetection rate. This superiority occur in both patients who had no risk factors fortuberculosis and in patients who had these risk factors, either disease (like DM,COPD) or receiving treatment (such as corticosteroids or anticancer chemotherapy)that alter the immune status. So, form the above explained superiority andadvantage, we can conclude that there is a good agreement that Bio-FM broth mayreplace Lowenstein Jensen medium in the future.Recommendations-Additional studies to assess the performance of the Bio-FM media under programconditions should be conducted, in comparison with solid media (like LowensteinJensen medium again) or with other liquid media, Bio-FM should also conductedin comparison with new culture system as BACTEC TB-460, BACTEC MGIT960,VersaTREK..-Bio-FM should be more evaluated with sputum samples, it should also beevaluated with different clinical specimens other than sputum, either respiratorylike brocho-alveolar lavage (BAL) or other clinical specimens like pleural effusion,CSF, gastric lavage, urine and stool.-Bio-FM should be evaluated in detecting non tuberculous mycobacteria (NTM)and for the ability in differentiation between NTM and MTB.-Bio-FM should be assessed for utility in relapsed or treatment failure tuberculosisand possibility to be modified for usage in drug sensitivity test (DST).Conclusion & recommendation94-Bio-FM should be evaluated for its utility in follow up of treatment regimens andtesting their efficacy.-Bio-FM should undergo economic evaluation either seldom or in comparison withother media specially Lowenstein Jensen.-With further evaluation, Bio-FM should be affordable in diagnostic laboratories oftuberculosis, not only for researches