Mycobacterium tuberculosis

isolates from 104 south Indian patients,

including 52 sensitive to Streptomycin (S),

Isoniazid, (H) and Rifampicin (R), and 52

resistant to SHR/HR were tested for their in

vitro susceptibility to Ciprofloxacin and

Ofloxacin on Lowenstein-Jensen medium. The

geometric mean for minimal inhibitory

concentration (MIC) of Ciprofloxacin was 2.00

mcg/ml for sensitive strains and 2.17 mcg/ml

for resistant strains, the overall mean being

2.08 mcg/ml. Considering Ofloxacin, the MICs

for the different categories of strains were

again similar, there being no difference

between sensitive and resistant strains, the

geometric means being 2.00 and 2.05 mcg/ml,

respectively

Paramasivan, C N

Prabhakar, R

Venkataraman, P

NIRT Institutional Repository

Original Article Ind. J. Tub., 1994, 41, 87IN VITRO ACTIVITY OF CIPROFLOXACIN AND OFLOXACIN AGAINSTSOUTH INDIAN ISOLATES OF MYCOBACTERIUM TUBERCULOSISP. Venkataraman1, C.N. Paramasivan2 and R Prabhakar3(Original received on 10.8.93; Revised version received on 16.12.93; Accepted on 9.2.94)Summary. Mycobacterium tuberculosisisolates from 104 south Indian patients,including 52 sensitive to Streptomycin (S),Isoniazid, (H) and Rifampicin (R), and 52resistant to SHR/HR were tested for their invitro susceptibility to Ciprofloxacin andOfloxacin on Lowenstein-Jensen medium. The  geometric mean for minimal inhibitory concentration (MIC) of Ciprofloxacin was 2.00mcg/ml for sensitive strains and 2.17 mcg/mlfor resistant strains, the overall mean being2.08 mcg/ml. Considering Ofloxacin, the MICsfor the different categories of strains were again similar, there being no difference  between sensitive and resistant strains, thegeometric means being 2.00 and 2.05 mcg/ml, respectively.  IntroductionDespite the rapid advances in treatment andthe availability of effective short coursechemotherapy regimens, tuberculosis continuesto be a common disease in the community.Tuberculosis is gaining increasing clinicalrelevance also because of its association with  HIV infection.1 Treatment for disease due todrug-resistant M. tuberculosis is more toxic, moreexpensive and not as successful as in disease dueto drug-sensitive organisms.2 Effective treatmentof patients with multi drug resistant organismswill be greatly facilitated by the development ofnewer anti-tuberculosis drugs.Interest in the quinolone group of drugs hasgrown during the last decade with thedevelopment of new derivatives such asNorfloxacin, Pefloxacin, Ofloxacin, Enoxacin,Lomefloxacin and Ciprofloxacin. Of these,Ciprofloxacin is among those with the lowestminimal inhibitory concentration (MIC) againstM. tuberculosis3 and is more active thanNorfloxacin and Enoxacin. 4,5 A recent study atTuberculosis Research Centre, Madras has givenpromising results with Ciprofloxacin on bothdrug-resistant and drug-sensitive isolates of M.Tuberculosis, in vitro.6Ofloxacin has been reported to be active bothin vitro and in vivo against mycobacteria.7 It was,therefore, proposed to test the in vitro activity ofOfloxacin on south Indian isolates of M.tuberculosis and compare it with that ofCiprofloxacin. The results of this investigationare reported in this paper.Material and MethodsStrains : A total of 104 clinical isolates of M.tuberculosis from as many patients was tested.These included 52 isolates sensitive toStreptomycin (S), Isoniazid (H) and Rifampicin(R), and 52 resistant to SHR or HR. Thestandard sensitive strain M. tuberculosis H37Rvwas also tested.Drug concentrations  : Ciprofloxacin andOfloxacin were incorporated in LowensteinJensen (LJ) medium slopes to give final (pre-inspissation) concentrations of 0.5, 1, 2, 4, 8, 16,32 and 64 mcg/ml.Sensitivity testing : A standard suspension (4mg/ml) of the strains, which were given codenumbers to conceal their identity, was inoculatedwith a 3mm loop on to 2 drug free LJ slopes andone LJ slope each, with the differentoncentrations of the drugs. All slopes were1. Senior Technical Officer (Bacteriology);2. Deputy Director (Bacteriology);.3. Director, Tuberculosis Research Centre (ICMR), Madras.Correspondence : Dr. R. Prabhakar, Director, Tuberculosis Research Centre (ICMR), Spurtank Road, Chetput,Madras-600 031.88 VENKATARAMAN ET AL.Table 1. Minimal inhibitory concentrations ofCiprofloxacin against south Indian isolates ofM. tuberculosisNo. of MIC* (mcg/ml)strains0.5 1 2 4SHR sensitive 52 1 1127 13SHR/HR resistant  52  1   4 35 12Total 104 2 15 62 25*No strain had an MIC > 4 mcg/ml.incubated at 37oC. And, at the end of 4 weeks ofincubation, the MIC was determined using the20-colony end point.8ResultsMIC for Ciprofloxacin : The standard strain,M. tuberculosis H37Rv, tested on three differentoccasions, gave an MIC of 1 mcg/ml.Considering the strains isolated from patients(Table l), even though 21% (11/52) of SHRsensitive strains had an MIC of 1 mcg/ml, asagainst 8% (4 out of 52) of SHR/HR resistantstrains, the corresponding proportions with MICof 2 mcg/ml were 52% and 67% respectively.This shift could have been due to experimentalvariation since the proportions of strains with anMIC of 4 mcg/ml were nearly identical. Thegeometric mean MICs were 2.00 mcg/ml forsensitive strains and 2.17 mcg/ml for resistantstrains, the overall mean being 2.08 mcg/ml.MIC for Ofloxacin : The MIC of Ofloxacin forM. tuberculosis H37Rv was 1 mcg/ml on the twooccasions tested. The distributions of the MICswith the two categories of strains were verysimilar, their being no difference betweensensitive and resistant strains, the geometricmean MICs being 2.00 and 2.05 mcg/ml,respectively (Table 2).DiscussionAlthough the currently used treatmentregimens for pulmonary tuberculosis arc quiteeffective in patients with drug sensitiveorganisms,the patients with drug resistantTable 2. Minimal inhibitory concentrations ofOfloxacin against south Indian isolates of M.tuberculosisNo. of MIC* (mcg/ml)s t r a i n s  0.5 1 2 4SHR sensitive 52 1 833 10SHR/HR resistant 52 1 7 33 11Total 104 2 15 66 21*No strain had an MIC > 4 mcg/ml.organisms, especially those resistant to Isoniazid  and Rifampicin, do not respond well to theseregimes.9 In view of the possibility of an increasein Rifampicin resistance among tuberculosispatients,there is an urgent need forinvestigations with the newer anti-tuberculosisdrugs.10 These newer drugs include theaminoglycosides,such as Amikacin andCapreomycin,the long acting Rifampicinderivatives, the fluoroquinoloncs andcombinations of beta-lactam antibiotics withbet -lactamase inhibitors.l0’1lConsidering first the aminoglycosides,although Amikacin is effective against M. avium-ntracellulare complex, its activity against M.tuberculosis low and, as such, it might not beeffective in the treatment of disease due to M.tub rculosis. 11 A recent study from this Centrerevealed that 6% of SHR sensitive and 15% ofSHR/HR resistant strains could be resistant to Capreomycin.6 As such, Capreomycin may haveonly a limited role in the treatment of patientswith multiple drug-resistant organisms.The rifamycin derivatives, Rifapentine andRifabutin have been reported to be more activetha  Rifampicin vitro against Rifampicinsensitive strains. Thus, Arioli and others12reported a 2 to 10 fold higher activity forRifapentine than Rifampicin. Recent studies atthis Centre revealed that although Rifapentineexhihited a significantly higher activity inRifampicin sensitive strains, there was completecross resistance in Rifampicin resistant strains.On the other hand, Rifabutin was not only moreeffective than Rifapentinein Rifampicin-sensitive strains but also a small proportionIN VITRO ACTIVITY OF CIPROFLOXACIN AND OFLOXACIN 89(22%) of Rifampicin-resistant strains weresusceptible to Rifabutin in vitro 13. Thus,Rifabutin might not only be useful to someextent in the treatment of disease due toRifampicin-resistant organisms but it couldpossibly delay the emergence of resistance to thecompanion drugs making it particularlysuitable for intermittent chemotherapy due toits longer half-life,The introduction of fluoroquinolones hasbroadened the range of therapeutic tools usedagainst mycobacterial diseases. Being a new classof compounds, there is no cross resistance withthe conventional anti-tuberculosis drugs.9 Of thevarious derivatives studied, Ciprofloxacin and   Ofloxacin have been reported to be most activein vitro against M. tuberculosis. 3,14,15 However, theabsorption of Ciprofloxacin after oraladministration is poor (mean C max 2.4 mcg/ml) with a relatively lower mean half life (4.1hours) compared to that of Ofloxacin (C max :11 mcg/ml; t 1/2 : 7 hours).16,17 Preliminarystudies have demonstrated that Ofloxacin iseffective against M. tuberculosis, in vitro as wellas in experimental murine tuberculosis.9 In arecent uncontrolled study conducted by theHong Kong Chest Services/British MedicalResearch Council,18 it has been reported thatOfloxacin is a relatively better drug in thetreatment of drug-resistant pulmonarytuberculosis patients than Rifabutin.The present investigation revealed that the invitro activity of Ofloxacin was similar to that ofCiprofloxacin, the overall geometric mean MICs     being 2.03 mcg/ml for Ofloxacin and 2.08 mcg/ml for Ciprofloxacin. The earlier reported lowergeometric means of MICs from this Centre6 w reperhaps a reflection of laboratory variations inmedium preparation, batches of drugs used anddoubling dilution concentrations shifting themean by one step. It may be observed that themean MIC for Ciprofloxacin is only slightlybelow the peak serum levels attainable withtherapeutic doses of the drug. However, inpulmonary and other tissues the drug may attainlevels in excess of those in serum which may beadequate to inhibit growth of strains.19,20 Themean MIC of Ofloxacin, however, is far belowthe peak serum level of 11 mcg/ml attainable atnormal dosage.16,17. Moreover, our resultsshowed that the MICs of both Ciprofloxacin andOfloxacin were within a narrow range of 1-4mcg/ml for most of the M. tuberculosis strainstested. Further, since no differences insusceptibility to Ciprofloxacin and Ofloxacinwere noted between strains sensitive or resistantto SHR, it can be concluded that there is no  cross resistance between these quinolones ands andard anti-tuberculosis drugs. Earlierstudies at this Centre also showed nosignificant differences in the activity ofCiprofloxacin between SHR sensitive andresistant strains.6The present investigation also suggests thatCiprofloxacin and Ofloxacin might be effective inthe treatment of patients with multiple drugresistant organisms. But their use in patientscould easily lead to the selection of resistantmutants. This, in turn, could mean resistance tothe other quinolones, as cross resistance is a well-known phenomenon among the quinolones.7Therefore, these quinolones might be useful inthe treatment of multidrugresistanttuberculosis only if used in judiciouscombination with other drugs to which thestrain is sensitive. Thus, the use ofCiprofloxacin or Ofloxacin in the chemotherapyof tuberculosis, including their role in thetreatment of failures to standard regimens, canonly be assessed after well planned controlledclinical trials.AcknowledgmentsThe authors are grateful to Mrs. DakshayaniGovindhan for technical assistance and Mrs.J thi Segaran for secretarial assistance.References1. Indian Council of Medical Research. HIVinfection-current status and future research plansICMR Bulletin; 1991, 21, 125.2. American Thoracic Society. Control oftuberculosis in the United States. Am. Rev.Resp. Dis; 1992, 146, 1623.3. Young, L.S., Berlin, O.G.W. and Inderleid, C.B.Activity of Ciprofloxacin and other fluorinatedquinolones against mycobacteria. Am. J. Med.;1987, 82, (Supl. 4A), 23.4. Gay J.D., Deyoung D.R. and Roberts G.D. Invitro activities of Norfloxacin and Ciprofloxacinagainst Mycobacterium tuberculosis, M. avium90 VENKATARAMAN ET AL.complex, M. chelonei, M. fortuitum andM.kansasii Antimicrob. Agents Chemother.; 1984,26, 94.5. Gaya H. and Chadwick N.V. In vitro activity ofCiprofloxacin against mycobacteria. Europ. J.Clin. Microbiol.; 1985, 4, 345.6. Venkataraman P., Paramasivan C.N. andPrabhakar R. In vitro activity of Capreomycinand Ciprofloxacin against south Indian isolatesof M. tuberculosis. Ind. J. Tub.; 1993, 40, 21.7. Truffot-Pernot, C., Ji. B. and Grosset, J.Activities of Pefloxacin and Ofloxacin againstmycobacteria- In vitro and mouse experiments.Tubercle; 1991, 72, 57.8. Canetti G., Fox W., Khomenko R., Mahler H.T.,Menon N.K., Mitchison, D.A., Rist, M. andSmelev, M.A. Advances in the technique oftesting mycobacterial drug sensitivity and the useof sensitivity tests in tuberculosis controlprogrammes. Bull. WHO; 1969, 41, 21.9. Parenti F. New experimental drugs for thetreatment of tuberculosis. Rev. Infect. Dis.; 1989,11, (Suppl. 2). 479.10. Mitchison D.A., Ellard GA. and Grosset J. Newantibacterial drugs for the treatment ofmycobacterial diseases in man. Brit. Med. Bull.;1988, 44, 757.11. Allen B.W., Mitchison, D.A., Chan Y.C., YewW.W. and Allen W.G.L. Anicanin in thetreatment of pulmonary tuberculosis. Tubercle;1993, 64, 111.12. Arioli V., Berti M., Cameti G., Randisi E. RossiE., and Scotti R. Antibacterial activity of MDL473, a new semisynthetic Rifamycin derivative, J.Antibiot. (Tokyo); 1981, 34, 1026.13. Venkatarman P.,Paramasivan C.N. andPrabhakar R. In vitro activity of Rifampicin,Rifapentine and Rifabutin against south Indianisolates of Mycobactetium tuberculosis. Ind. J.Tub.; 1993, 40, 17.14  Leysen D.R., Haemers A and Pattyn S.R.Mycobacteria and the new quinolones (Minireview). Antimicrob. Agents Chemother.; 1989,33, 1.15. Van Caekenberghe, D. Comparative in v troactivities of ten fluoroquinolones and fusidic acidagainst Mycobacterium spp. J. Antimicrob.Chemother.; 1990, 26, 381.16. Hooper D.C. and Wolfson T.S. Thefluoroquinolones-pharmacology, clinical usesand toxicities in man (Mini review). Antimicrob.Agents Chemother.; 1985, 2 , 716.17. Wise R., Lister D., McNulty C.A.M., Griggs, D.and Andrews,J.M. The comparativepharmacokineticsof five quinolones. J.Antimicrob. Chemother.; 1986, 18 (suppl. D),71.1 . Hong Kong Chest Service/British MedicalResearch Council. A controlled study ofRifabutin and an uncontrolled study of Ofloxacinin the retreatment of patients with pulmonarytuberculosis resistant to Isoniazid, Streptomycinand Rifampicin. Tubercle and Lung Disease;1992, 73, 59.19. Marinis E. and Legakis N.J. In vitro activity ofCiprofloxacin against clinical isolates ofmycobacteriaresistant toantimycobac-terial drugs. J. Antimicrob. Chemother.; 1985,16, 52720. Mehra, P and Aggarwal, K.K. Ciprofloxacin-anew quinolone antibiotic. Ind. J. Clin. Pract.;1990, 1, 38.

In vitro activity of ofloxacin and ciprofloxacin against South Indian isolates of M. tuberculosis

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In vitro activity of ofloxacin and ciprofloxacin against South Indian isolates of M. tuberculosis

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