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Topical treatment of cutaneous leishmaniasis in belize: In vitro and in vivo studies with Leishmania mexicana
lnrrrnarronal Journal/or Prrnrrd in Great Brirain
Parasitology
Vol. 23, No.
I. pp.121-127,
1993 I
002&7519/93 $6.00 + 0.00 Pergamon Press Lrd Socreryfor Parosrrology
1993 Aumdran
TOPICAL TREATMENT OF CUTANEOUS LEISHMANIASIS IN BELIZE: IN VITRO AND IN VZVO STUDIES WITH LEISHMANIA MEXICANA J. EL-ON,*?
F. CAWICH,~
D. A. EVANS~
and L. WEINRAUCH~~
*Department of Microbiology and Immunology, Faculty of Health Sciences, Ben Gurion
§London
Beer Sheva 84105, Israel fBelize City Hospital, Belize, Belize School of Hygiene and Tropical Medicine, London, IiHadassah Medical Center, Jerusalem, Israel (Received 5 November
University
of the Negev,
U.K.
1991; accepted 7 July 1992)
Abstract-EL-ON J., CAWICH F., EVANS D. A. and WEINRAUCH L. 1993. Topical treatment of cutaneous leishmaniasis in Belize: in vitro and in viva studies with Leishmaniu mexicana. International Journal for Parasitology 23: 121-127. Strains of Leishmania mexicana isolated from Belizian patients were found to be highly susceptible to paromomycin sulphate (PR) treatment. This drug at 100 pg ml-’ destroyed 85-99.5% of in vitro cultivated Leishmaniu promastigotes within 4 days of exposure to the drug. Leishmaniu promastigotes inoculated into the base of the tail of Balb/c mice caused the development of local lesions several weeks after infection. These lesions were totally cleared of parasites after 20 days of topical treatment with PR ointment, comprised of 15% paromomycin sulphate and 12% methylbenzethonium chloride in soft white paraffin. Similar results were also obtained with L. braziliensis infections. Isoenzyme analysis was found to be the method of choice for parasite strain identification. Excreted factor serotyping was only partially effective and promastigote agglutination gave negative results. INDEX
KEY WORDS:
Leishmania
mexicana; identification;
INTRODUCTION CUTANEOUS leishmaniasis two
major
infecting
parasite
(CL) in Belize is caused
species:
approximately
75%
Leishmania of
patients
causing
the remaining
braziliensis and
t To whom all correspondence
L.
25%
should
topical treatment.
Weinrauch, 1987). The present study is aimed at determining the efficacy of this treatment against Belizian Leishmaniu strains, both in vitro in culture and in vivo in experimental animals, before its application to humans.
by
of cases (Lainson & Strangways-Dixon, 1963; Evans, Lanham, Baldwin & Peters, 1984). Both species are associated with the development of large nodulo-ulcerative lesions that heal slowly leaving ugly scars. No accurate estimation of the incidences of the disease in Belize is available at the present time. However, according to the local medical authorities, hundreds of cases are annually reported, mainly in the southern and western parts of the country. Many of these patients are soldiers of the Belizian Defence Forces. Recently, a topical treatment of CL using an ointment comprised of 15% paromomycin sulphate (PR) and 12% methylbenzethonium chloride (MBCl) (PR ointment) was developed. This treatment was found to be highly effective against CL caused by various strains of Leishmaniu (see El-On, Jacobs & mexicana
paromomycin;
MATERIALS
AND METHODS
Parasite strains and host animals. Eleven Belizian strains of Leishmania parasites including seven isolates of L. mexicana (BEL 44, BEL 46, BEL 47, BEL 58, BEL 64, BEL 66 and BEL 69) and four isolates of L. braziliensis (BEL 75, BEL 101, BEL 102 and BEL 103) have been used in this study. All strains were isolated by one of us (D.A.E.) from patients infected in Belize. They were kept as stabilates in liquid nitrogen and subsequently maintained in vitro at 28’C by twice weekly passage in modified Tobie’s blood agar medium. Infective parasites were maintained in vivo in Balb/c mice. Rabbits were used as a source of normal blood for preparing culture media and for raising specific antisera. Blood, whether normal or immune, was collected by cardiac puncture. Parasite identiJication. Identification of the leishmanial strains was made using: (a) morphological description of the promastigotes which developed in culture at 28°C; (b) a parasite microagglutination test; (c) isoenzyme analysis and (d) excreted factor (EFS) serotyping. Morphological characterization. Parasites were cultivated
be addressed. 121
J. Ei_-ON, F. CAWICH, D. A.
122
TABLE I-DIRECT AGGLUTINATIONOF Lei~hmnniu PROMAS’TIOOTES BYRABBITANTI-L. mexicana (BEL 69) ANTISERUM
L. mexicunu
BEL 44
L. mexicana BEL 46 L. mexicana BEL 58 L. mexicana BEL 64 L. mexicana BEL 69 L. mexicuna BEL 73 L. major LRC-L137
10
20
+ + +
i + +
Agglutination 40 80 + + +
Sr -t I
titre 160 320 -
640 -
.t
+
Z!C -
-
-
-
+ + +
+ + +
+ + +
& i +
+
+
+ + +
in modified Tobie’s medium using RPM1 I640 medium (Beth Haemek, Israel) as overlay. On the fourth day of cultivation, when the parasites were at the logarithmic phase, the cells were examined under the phase microscope and their morphology described (Evans et al., 1984). Parasite microagglutination test. A microagglutination test using trypsin-treated, formalin-fixed, Coomassie blue-stained Leishmania promastigotes was performed according to the method of Harith, Laarman, Minter-Goedbloed, Kager & Kolk (1987). Agglutination results were recorded macroscopically and microscopically after I8 h incubation at room temperature. Isoenqme analysis. The isoenzyme profiles of the Belizian isolates were compared using the following enzymes: alanine amino-transferase (ALAT); aspartate aminotransferase (ASAT); glucose-&phosphate dehydrogenase (G6-PDH); glucose phosphate isomerase (GPI): malic enzyme (ME); malate dehydrogenase (MDH); mannose phosphate isomerase (MPI); 6.phosphogluconate dehydrogenase (6-PGDH); phosphoglucomutase (PGM) and superoxide dismutase (SOD) (Evans rt al., 1984). EFS preparation. Promastigotes and their EFS were harvested from cultures grown in either blood agar medium or RPM1 1640 medium. For EFS preparation, the culture at the logar~th~l~c phase was centrifuged for 10 min at 1300~ at room temperature. The supernatant fluid was harvested and centrifuged again at 12,000 g for 30 min at 4”C, filtered through a Millipore filter of 0.45 pm pore size, concentrated IO-fold by freeze drying and stored at - 20°C until used. Anriseraproduction in rabbits. Antisera were raised in male rabbits of 2.5-3 kg against living promastigotes following the regimen of Adler, Foner & Montilio (1966). Six intravenous inoculations (I X IO’, 2 x 10’. 8 x lo’, 16 x lo’, 32 x 107) were given at weekly intervals, and blood samples were collected 10 days after the last injection. The ability of the antibody produced to precipitate leishmania1 EFS and to agglutinate Leishmania promastigotes was tested. Immunodf~usio~ and immul2oefecrritphorrsh. Immunodiffusion and immunoelectrophoresis were performed in I. I % agarose in 0.041 M-barbiturate buffer pH 8.2 containing 0.02% sodium azide. The preparations were developed for I 4 days in moist diffusion chambers at 4°C. and photographed after rinsing with saline to remove excess protein, drying and staining with amino black.
EVANS
and L. WEI~RA~~CH
The effect of paromomycin on leishmanial devefopmenr in vitro. The effect of paromomycin sulphate (PR) (Farmitalia, Italy) on the growth of leishmanial promastigotes was tested at 28°C in RPM1 1640medium supplemented with 20% FCS, 100 units penicillin and 100 pg streptomycin per ml. The promastigotes were first grown in modified blood agar medium, then transferred to RPM1 medium containing various concentrations of PR on day 1 of the experiment. Parasite growth was assessed by daily haemocytometer counts and the growth rates, as compared with the normal untreated controls, calculated. Efleect qf PR o~?ltrneriton the lei,~hma~iulde~l@iopmentin vivo. The methods used to infect mice and score PR ointment efficacy wereasdescribed previously (El-On, Jacobs, Witztum & Greenblatt, 1984). Male Balbjc mice were inoculated intradermally in the base of the tail with 0.5-I x IO’ promastigotes. Treatment with PR ointment was started 4580 days after infection. The ointment was applied to the lesions twice daily for a period of IO-20 days. Lesion development was inspected macroscopically and the presence of parasites in biopsy material was monitored microscopically, in both smear and cultures. Lesion size was measured in millimetres by two diameters (D.d) taken at right angles and determined according to the formula S mm’ = D x d/2. Protozoological examinations were performed prior to treatment, 10 days after the beginning of treatment. at the end of the treatment and at various times after termination of treatment. RESULTS
Strain identtjication The results obtained for parasite identification were as follows. Morp~oiog~ca~chara~ter~zation. Promastigotes of L. hraziliensis maintained at 28°C in mid-exponential growth phase were characteristically very small (7.5 pm) with very short flagella, the organisms usually growing in clumps with almost no movement. L. mexicana promastigotes grew as elongated parasites (20 pm) with long flagella. The parasites were highly motile and grew as either free promastigotes or in closely packed rosettes. Microagglutination. The results obtained with the microagglutination test are summarized in Table 1. The highest agglutination titre (t:80) was obtained with L. mexicana BEL 69 against the homologous rabbit antiserum. Titres of 1:20-I:80 were observed with the other L. mexicana isolates. A higher titre (1:320) was obtained with rabbit anti-l. mexicunu against the heterologous L. major strain (Table I). Excreied .factor (EFSj sewtyping. Schnur. Zuckerman & Greenblatt (1972) showed that leishmanial EFS are precipitated by antibody raised in rabbits against living homologous promastigotes. In the present study, the antiserum raised in rabbits against L. mexicuna BEL 69 and against L. hraziliensis (BELl 0 1; BEL103) did not distinguish between t. mesirana and
Treatment
0 CONTROL BEL 44 g ‘“1 I
of Belizian cutaneous
l
DAYS AFTER
10 pg/ml
A 100 pg/ml
BEL 46
TIrn
123
leishmaniasis
BEL 41
Is00 1
DRUG ADMINISTRATION
FIG. I. The effect of paromomycin sulphate on the growth of various L. mexicana isolates, untreated or treated with the drug at 10 or 100 pg ml ’ in culture at 28’C.
10 pg/ml
0
0
I
*
3
4
DAYS AFTER FIG. 2. The effect of paromomycin L. braziliensis
sulphate
I
*
3
.
.
I
2
3
4
DRUG ADMINISTRATION on the growth
All of the L. mexicana and L. were recognized by these antisera producing one-three clear precipitating arcs by immunodiffusion and immunoelectrophoresis. No cross-reactivity was obtained between L. mexicana strains.
braziliensis isolates examined
100 pg/ml
A
.
either
of L. mexicana isolates in culture at 28’C.
and L. major when either rabbit anti-L. mexicana or rabbit anti-L. major antisera were used. Effect of paromomycin on L. mexicana promastigote development in vitro The anti-leishmanial activity of PR against the
10 5 5 5 5 5
L. major LRC-L137 L. mexicana BEL 44 L. mexicano BEL 46 L. mexiconu BEL 58 L. mexicana BEL 64
L. mexicana BEL 69 85
45 80 70 70 85
Day started after inoculation
0.24zkO.01
0.65 rl:0.37 0.08 f 0.01 0.38 f 0.25 0.64~0.30 0.63 jc 0.40 0
0.1 zk1.5 0 0 0.2 It 3.0 0
Pretreatment 30 days after end of treatment
SD
L. major
O/5
O/l0 O/5 O/5 O/5 O/5
L. mexicana IN BALBL
MICE
O/5
OjlO O/5 O/5 015 O/5
0
515
o/10 515 515 515 515
515
IO]10 515 515 5/5 515
5/5
lo/lo 515 515 5/5 515
30
.” - .” - .” ,_~“__l ,.__” .__-“.I”.c~-~-~”
5/5
Oil0 515 515 515 515
Days after end of treatment 5 10 20
Therapeutic response Number of cured lesions/Number of survivors
AND
Pretreatment
WI’PH PR OINTMENT ON
Mean lesion size (mm’) f
EFFECTOF A TCWCALTREATMENT
The mice were treated twice daily for 20 days.
No. of mice in group
Parasite
TABLE ~--THE
S
e:
; F P ? w f ?I E
5!
?1
“2
b
F
4
_
Treatment
DAYS
of Belizian cutaneous
TREATED
leishmaniasis
125
UNTREATED
80
FIG. 3. The effect of topical treatment with PR ointment on L. mexicana BEL 64 in Balb/c mice. The mice were inoculated in the base of the tail with 1 x 10’ promastigotes.
Treatment was applied twice daily for 20 days starting 85 days after parasite inoculation (A). The numbers indicate days after the end of treatment.
various L. mexicana isolates is shown in Figs. 1 and 2. PR at 10 pg ml-’ inhibited the growth of the parasites by 47-80%, and this drug at 100 pug ml-’ inhibited the growth by 855 99.5% within 4 days of exposure to the drug. BEL 44 was slightly more resistant to PR than the other strains showing about 85% growth inhibition rate after 4 days of exposure to PR at 100 pg ml-‘. Effect of topical treatment on L. mexicana development in Balblc mice Only six isolates of L. mexicana (BEL 44, BEL 46, BEL 58, BEL 64, BEL 69 and BEL 73) and three
isolates of L. braziliensis (BEL 101, BEL 102 and BEL 103) were found to be infective to Balb/c mice. The remaining isolates L. mexicana BEL 47 and L. braziliensis BEL 75 did not infect the mice even when high doses of 1 x lo8 promastigotes were inoculated into young, 4-week-old mice. All of the infective L. mexicana isolates were found to be highly virulent to Balb/c mice. Four-five weeks after the inoculation of 0.5-l x 10’ promastigotes into the base of the tail of Balb/c mice, a big nodule developed. One week later, the nodule transformed
126
J. EL-ON, F. CAWKX, D. A.
into an ulcer which increased in size up to 34.7 + 8.8 mm’ and 134.6 + 28.7 mm’ in diameter (average of 27 mice) in a period of 9 and 13 weeks after infection, respectively. Fifty per cent of the mice died during the fifth month after infection. Treatment with PR ointment twice daily for only 10 days was not sufficient to eliminate all of the parasites, although an improvement was noted. After 20 days of treatment, parasites were no longer detectable in the area of the lesions in all of the infected animals, and open lesions completely healed within a period of 3040 days (Fig. 3, Table 2). PR ointment was only slightly less effective against L. major infection in Balb/c mice (Table 2). After 20 days treatment, parasites were still found to be present in the lesions, However, the parasites were undetectable 20 days after termination of treatment.
EVANS
and L. WEIN~~~~H
that each new batch of PR should be examined against Leishmania both in vitro in tissue culture and in viva in experimental animals prior to its application to clinical study. PR is considered effective only if (a) PR at IO ~16 amastigotes ml-’ totally eliminates the intracellular from infected macrophages within 4 days of exposure to thedrug, and (b) ISi 12 PR ointment applied twice daily to the CL lesion caused by L. major in Balb/c mice cured the lesion after 6 days treatment. Indeed, with a new batch of PR recently received, 610 days treatment with PR ointment was sufficient to eliminate all of the L. muicano and L. ~ra~~~~e~~~ parasites from the CL lesions. Based on the results obtained in this study, a clinical trial with PR ointment has recently been started in Belize. Preliminary results indicate a high efficacy of PR ointment against both I!,. mexicana and L. braziliensis. Final results of the clinical study will be published elsewhere.
DISCUSSION
Identification of the leishmanial strains is generally carried out by either EF-serotyping, isoenzyme analysis or DNA hybridization (Chang & Bray, 1985). In this study, an attempt was made to use simple techniques and simple facilities for parasite identification. Three techniques were used to identify the Belizian isolates: the microagglutination test, EFserotyping and isoenzyme analysis. The microagglutination test that was recently found to be highly indicative in visceral leishmaniasis (Harith, Kolk, Leeuwenburg, Muigai, Huigen, Jelsma & Kagar, 1988) and CL (Mengistu, Kiessling & Akuffo, 1990), and the EF-serotyping proved to be only partially effective in identifying the Belizian leishmanial isolates. However, the isoenzyme analysis was shown to be a highly reliable and reproducible method for distinguishing leishmanial species. The Belizian L. mexicana strains were found to be highly susceptible to PR treatment showing 85% inhibition of promastigote growth within 4 days of exposure to PR at 100 pg ml-‘. Topical treatment of Belizian L. mexicana lesions in mice was also highly effective. Although 1Odays treatment was not sufficient to eliminate all of the parasites from the lesions, total elimination was achieved at the end of 20 days treatment. The results obtained with the Belizian strains were even better than those obtained with the L. major strain. In our previous study (El-On et al.. 1984) 6 days of treatment were sufficient to cure the CL (L. major) lesions in Balb/c mice, while in the present study, even 20 days treatment did not totally eliminate t. major parasites. An intensive study made recently irz vitro on cultivated infected macrophages and in vivo in infected Balb/c mice revealed that the PR batch received was not as effective as the original batch received several years ago. We have recently learned
Acknowledgements--This study was supported by the AIDCDR Grant No. DPE-5544-G-SS-7047-00. Paromomycin sulphate was kindly supplied by Parke Davis Warner Lambert, Italy and Farmitalia. Carlo Erba. Italy. REFERENCES ADLER S., FONER A.
& MONTILIO B. 1966. The relationship between human and animal strains of Leishmania from the Sudan. Transactionsof the Royal Sociery of Tropical Medicine and Hygiene 60: 380-386.
CHANG K. P. & BRAY R. S. 1985. Humnn Parasitic
DLwrr.rt~.r.
Vol. I, ~i.~hr~zu~i~~~.~.Elsevier, Amsterdam. EL-ON J., JACOBS G. P., WITZT~M E. & GREENBLATTC. L. 1984. The development of topical treatment for cutaneous leishmaniasis due to Leishmania major in experimental
animals.
Antimicrobial
EL-ON J.. JACOBS G. chemotherapy
rlgents Chemothcrap.v P. & WEINRAI.CH L.
of cutaneous
I.
26: 745-75
1987. Topical
leishmaniasis.
Parusitolog.~
Tuduy 4: 768 t . EVANS
D. A.,
LANXN
S.
M.,
BALDWIN C. 1. & PETERS W.
1984. The isolation and isoenzyme characterization of Leishmunia braziliensis subsp. from patients with cutaneous leishmaniasis acquired in Belize, Trwzsactions of’ rhe Royal Society of‘ Tropical Medicine und Hygiene 18: 3542. HARITH A. E., LAARMANJ. J.. MINTER-G• EL)BLOED E., KU:R P. A. & KOLK A. H. J. 1987. Trypsin-tr~dted and Coomassie blue-stained epimastigote antigen in a microagglutination test for Chagas’ diseases. American Journal qf Tropical Medicine and Hygiene 37: 66-l 1. HARITH A. E., KOLK A. H. J., LEEUWENNJR~J., MUIGAI R., HUI~EN E., JELSMAT. & KA(JAR P. A. 1988. Improvement a direct
agglutination
test for
fieid
studies
of
of
visceral
leishman~~is. ~~~~r~u~ ~~C~~~j~u~ ~ic~~b~~~~~~ 26: 132 1-I 325. LAINS~N R.
& STKANGWAYS-DIXON J. 1963. L~ishmu~iu mexicana: the epidemiology of dermal leishmaniasis in British Honduras. Transactions of the Royul Society of Tropical Medicine and Hygiene 51: 242-265. MI~N~ISTUG.. KIESSLINOR. &AK~FFoH. 1990. Thevalue ofa direct agglutination test in the diagnosis of cutaneous and
Treatment
of Belizian cutaneous
visceral leishmaniasis in Ethiopia. Transacfions of the Royal Society of Tropical Medicine and Hygiene 84: 359-362. SCHNURL. R., ZUCKERMANA. & GREENBLATTC. L. 1972.
leishmaniasis
127
Leishmanial serotypes as distinguished by the gel diffusion of factors excreted in vitro and in vivo. Israel Journal of Medical Sciences 8: 932-942.
Parasitology
Vol. 23, No.
I. pp.121-127,
1993 I
002&7519/93 $6.00 + 0.00 Pergamon Press Lrd Socreryfor Parosrrology
1993 Aumdran
TOPICAL TREATMENT OF CUTANEOUS LEISHMANIASIS IN BELIZE: IN VITRO AND IN VZVO STUDIES WITH LEISHMANIA MEXICANA J. EL-ON,*?
F. CAWICH,~
D. A. EVANS~
and L. WEINRAUCH~~
*Department of Microbiology and Immunology, Faculty of Health Sciences, Ben Gurion
§London
Beer Sheva 84105, Israel fBelize City Hospital, Belize, Belize School of Hygiene and Tropical Medicine, London, IiHadassah Medical Center, Jerusalem, Israel (Received 5 November
University
of the Negev,
U.K.
1991; accepted 7 July 1992)
Abstract-EL-ON J., CAWICH F., EVANS D. A. and WEINRAUCH L. 1993. Topical treatment of cutaneous leishmaniasis in Belize: in vitro and in viva studies with Leishmaniu mexicana. International Journal for Parasitology 23: 121-127. Strains of Leishmania mexicana isolated from Belizian patients were found to be highly susceptible to paromomycin sulphate (PR) treatment. This drug at 100 pg ml-’ destroyed 85-99.5% of in vitro cultivated Leishmaniu promastigotes within 4 days of exposure to the drug. Leishmaniu promastigotes inoculated into the base of the tail of Balb/c mice caused the development of local lesions several weeks after infection. These lesions were totally cleared of parasites after 20 days of topical treatment with PR ointment, comprised of 15% paromomycin sulphate and 12% methylbenzethonium chloride in soft white paraffin. Similar results were also obtained with L. braziliensis infections. Isoenzyme analysis was found to be the method of choice for parasite strain identification. Excreted factor serotyping was only partially effective and promastigote agglutination gave negative results. INDEX
KEY WORDS:
Leishmania
mexicana; identification;
INTRODUCTION CUTANEOUS leishmaniasis two
major
infecting
parasite
(CL) in Belize is caused
species:
approximately
75%
Leishmania of
patients
causing
the remaining
braziliensis and
t To whom all correspondence
L.
25%
should
topical treatment.
Weinrauch, 1987). The present study is aimed at determining the efficacy of this treatment against Belizian Leishmaniu strains, both in vitro in culture and in vivo in experimental animals, before its application to humans.
by
of cases (Lainson & Strangways-Dixon, 1963; Evans, Lanham, Baldwin & Peters, 1984). Both species are associated with the development of large nodulo-ulcerative lesions that heal slowly leaving ugly scars. No accurate estimation of the incidences of the disease in Belize is available at the present time. However, according to the local medical authorities, hundreds of cases are annually reported, mainly in the southern and western parts of the country. Many of these patients are soldiers of the Belizian Defence Forces. Recently, a topical treatment of CL using an ointment comprised of 15% paromomycin sulphate (PR) and 12% methylbenzethonium chloride (MBCl) (PR ointment) was developed. This treatment was found to be highly effective against CL caused by various strains of Leishmaniu (see El-On, Jacobs & mexicana
paromomycin;
MATERIALS
AND METHODS
Parasite strains and host animals. Eleven Belizian strains of Leishmania parasites including seven isolates of L. mexicana (BEL 44, BEL 46, BEL 47, BEL 58, BEL 64, BEL 66 and BEL 69) and four isolates of L. braziliensis (BEL 75, BEL 101, BEL 102 and BEL 103) have been used in this study. All strains were isolated by one of us (D.A.E.) from patients infected in Belize. They were kept as stabilates in liquid nitrogen and subsequently maintained in vitro at 28’C by twice weekly passage in modified Tobie’s blood agar medium. Infective parasites were maintained in vivo in Balb/c mice. Rabbits were used as a source of normal blood for preparing culture media and for raising specific antisera. Blood, whether normal or immune, was collected by cardiac puncture. Parasite identiJication. Identification of the leishmanial strains was made using: (a) morphological description of the promastigotes which developed in culture at 28°C; (b) a parasite microagglutination test; (c) isoenzyme analysis and (d) excreted factor (EFS) serotyping. Morphological characterization. Parasites were cultivated
be addressed. 121
J. Ei_-ON, F. CAWICH, D. A.
122
TABLE I-DIRECT AGGLUTINATIONOF Lei~hmnniu PROMAS’TIOOTES BYRABBITANTI-L. mexicana (BEL 69) ANTISERUM
L. mexicunu
BEL 44
L. mexicana BEL 46 L. mexicana BEL 58 L. mexicana BEL 64 L. mexicana BEL 69 L. mexicuna BEL 73 L. major LRC-L137
10
20
+ + +
i + +
Agglutination 40 80 + + +
Sr -t I
titre 160 320 -
640 -
.t
+
Z!C -
-
-
-
+ + +
+ + +
+ + +
& i +
+
+
+ + +
in modified Tobie’s medium using RPM1 I640 medium (Beth Haemek, Israel) as overlay. On the fourth day of cultivation, when the parasites were at the logarithmic phase, the cells were examined under the phase microscope and their morphology described (Evans et al., 1984). Parasite microagglutination test. A microagglutination test using trypsin-treated, formalin-fixed, Coomassie blue-stained Leishmania promastigotes was performed according to the method of Harith, Laarman, Minter-Goedbloed, Kager & Kolk (1987). Agglutination results were recorded macroscopically and microscopically after I8 h incubation at room temperature. Isoenqme analysis. The isoenzyme profiles of the Belizian isolates were compared using the following enzymes: alanine amino-transferase (ALAT); aspartate aminotransferase (ASAT); glucose-&phosphate dehydrogenase (G6-PDH); glucose phosphate isomerase (GPI): malic enzyme (ME); malate dehydrogenase (MDH); mannose phosphate isomerase (MPI); 6.phosphogluconate dehydrogenase (6-PGDH); phosphoglucomutase (PGM) and superoxide dismutase (SOD) (Evans rt al., 1984). EFS preparation. Promastigotes and their EFS were harvested from cultures grown in either blood agar medium or RPM1 1640 medium. For EFS preparation, the culture at the logar~th~l~c phase was centrifuged for 10 min at 1300~ at room temperature. The supernatant fluid was harvested and centrifuged again at 12,000 g for 30 min at 4”C, filtered through a Millipore filter of 0.45 pm pore size, concentrated IO-fold by freeze drying and stored at - 20°C until used. Anriseraproduction in rabbits. Antisera were raised in male rabbits of 2.5-3 kg against living promastigotes following the regimen of Adler, Foner & Montilio (1966). Six intravenous inoculations (I X IO’, 2 x 10’. 8 x lo’, 16 x lo’, 32 x 107) were given at weekly intervals, and blood samples were collected 10 days after the last injection. The ability of the antibody produced to precipitate leishmania1 EFS and to agglutinate Leishmania promastigotes was tested. Immunodf~usio~ and immul2oefecrritphorrsh. Immunodiffusion and immunoelectrophoresis were performed in I. I % agarose in 0.041 M-barbiturate buffer pH 8.2 containing 0.02% sodium azide. The preparations were developed for I 4 days in moist diffusion chambers at 4°C. and photographed after rinsing with saline to remove excess protein, drying and staining with amino black.
EVANS
and L. WEI~RA~~CH
The effect of paromomycin on leishmanial devefopmenr in vitro. The effect of paromomycin sulphate (PR) (Farmitalia, Italy) on the growth of leishmanial promastigotes was tested at 28°C in RPM1 1640medium supplemented with 20% FCS, 100 units penicillin and 100 pg streptomycin per ml. The promastigotes were first grown in modified blood agar medium, then transferred to RPM1 medium containing various concentrations of PR on day 1 of the experiment. Parasite growth was assessed by daily haemocytometer counts and the growth rates, as compared with the normal untreated controls, calculated. Efleect qf PR o~?ltrneriton the lei,~hma~iulde~l@iopmentin vivo. The methods used to infect mice and score PR ointment efficacy wereasdescribed previously (El-On, Jacobs, Witztum & Greenblatt, 1984). Male Balbjc mice were inoculated intradermally in the base of the tail with 0.5-I x IO’ promastigotes. Treatment with PR ointment was started 4580 days after infection. The ointment was applied to the lesions twice daily for a period of IO-20 days. Lesion development was inspected macroscopically and the presence of parasites in biopsy material was monitored microscopically, in both smear and cultures. Lesion size was measured in millimetres by two diameters (D.d) taken at right angles and determined according to the formula S mm’ = D x d/2. Protozoological examinations were performed prior to treatment, 10 days after the beginning of treatment. at the end of the treatment and at various times after termination of treatment. RESULTS
Strain identtjication The results obtained for parasite identification were as follows. Morp~oiog~ca~chara~ter~zation. Promastigotes of L. hraziliensis maintained at 28°C in mid-exponential growth phase were characteristically very small (7.5 pm) with very short flagella, the organisms usually growing in clumps with almost no movement. L. mexicana promastigotes grew as elongated parasites (20 pm) with long flagella. The parasites were highly motile and grew as either free promastigotes or in closely packed rosettes. Microagglutination. The results obtained with the microagglutination test are summarized in Table 1. The highest agglutination titre (t:80) was obtained with L. mexicana BEL 69 against the homologous rabbit antiserum. Titres of 1:20-I:80 were observed with the other L. mexicana isolates. A higher titre (1:320) was obtained with rabbit anti-l. mexicunu against the heterologous L. major strain (Table I). Excreied .factor (EFSj sewtyping. Schnur. Zuckerman & Greenblatt (1972) showed that leishmanial EFS are precipitated by antibody raised in rabbits against living homologous promastigotes. In the present study, the antiserum raised in rabbits against L. mexicuna BEL 69 and against L. hraziliensis (BELl 0 1; BEL103) did not distinguish between t. mesirana and
Treatment
0 CONTROL BEL 44 g ‘“1 I
of Belizian cutaneous
l
DAYS AFTER
10 pg/ml
A 100 pg/ml
BEL 46
TIrn
123
leishmaniasis
BEL 41
Is00 1
DRUG ADMINISTRATION
FIG. I. The effect of paromomycin sulphate on the growth of various L. mexicana isolates, untreated or treated with the drug at 10 or 100 pg ml ’ in culture at 28’C.
10 pg/ml
0
0
I
*
3
4
DAYS AFTER FIG. 2. The effect of paromomycin L. braziliensis
sulphate
I
*
3
.
.
I
2
3
4
DRUG ADMINISTRATION on the growth
All of the L. mexicana and L. were recognized by these antisera producing one-three clear precipitating arcs by immunodiffusion and immunoelectrophoresis. No cross-reactivity was obtained between L. mexicana strains.
braziliensis isolates examined
100 pg/ml
A
.
either
of L. mexicana isolates in culture at 28’C.
and L. major when either rabbit anti-L. mexicana or rabbit anti-L. major antisera were used. Effect of paromomycin on L. mexicana promastigote development in vitro The anti-leishmanial activity of PR against the
10 5 5 5 5 5
L. major LRC-L137 L. mexicana BEL 44 L. mexicano BEL 46 L. mexiconu BEL 58 L. mexicana BEL 64
L. mexicana BEL 69 85
45 80 70 70 85
Day started after inoculation
0.24zkO.01
0.65 rl:0.37 0.08 f 0.01 0.38 f 0.25 0.64~0.30 0.63 jc 0.40 0
0.1 zk1.5 0 0 0.2 It 3.0 0
Pretreatment 30 days after end of treatment
SD
L. major
O/5
O/l0 O/5 O/5 O/5 O/5
L. mexicana IN BALBL
MICE
O/5
OjlO O/5 O/5 015 O/5
0
515
o/10 515 515 515 515
515
IO]10 515 515 5/5 515
5/5
lo/lo 515 515 5/5 515
30
.” - .” - .” ,_~“__l ,.__” .__-“.I”.c~-~-~”
5/5
Oil0 515 515 515 515
Days after end of treatment 5 10 20
Therapeutic response Number of cured lesions/Number of survivors
AND
Pretreatment
WI’PH PR OINTMENT ON
Mean lesion size (mm’) f
EFFECTOF A TCWCALTREATMENT
The mice were treated twice daily for 20 days.
No. of mice in group
Parasite
TABLE ~--THE
S
e:
; F P ? w f ?I E
5!
?1
“2
b
F
4
_
Treatment
DAYS
of Belizian cutaneous
TREATED
leishmaniasis
125
UNTREATED
80
FIG. 3. The effect of topical treatment with PR ointment on L. mexicana BEL 64 in Balb/c mice. The mice were inoculated in the base of the tail with 1 x 10’ promastigotes.
Treatment was applied twice daily for 20 days starting 85 days after parasite inoculation (A). The numbers indicate days after the end of treatment.
various L. mexicana isolates is shown in Figs. 1 and 2. PR at 10 pg ml-’ inhibited the growth of the parasites by 47-80%, and this drug at 100 pug ml-’ inhibited the growth by 855 99.5% within 4 days of exposure to the drug. BEL 44 was slightly more resistant to PR than the other strains showing about 85% growth inhibition rate after 4 days of exposure to PR at 100 pg ml-‘. Effect of topical treatment on L. mexicana development in Balblc mice Only six isolates of L. mexicana (BEL 44, BEL 46, BEL 58, BEL 64, BEL 69 and BEL 73) and three
isolates of L. braziliensis (BEL 101, BEL 102 and BEL 103) were found to be infective to Balb/c mice. The remaining isolates L. mexicana BEL 47 and L. braziliensis BEL 75 did not infect the mice even when high doses of 1 x lo8 promastigotes were inoculated into young, 4-week-old mice. All of the infective L. mexicana isolates were found to be highly virulent to Balb/c mice. Four-five weeks after the inoculation of 0.5-l x 10’ promastigotes into the base of the tail of Balb/c mice, a big nodule developed. One week later, the nodule transformed
126
J. EL-ON, F. CAWKX, D. A.
into an ulcer which increased in size up to 34.7 + 8.8 mm’ and 134.6 + 28.7 mm’ in diameter (average of 27 mice) in a period of 9 and 13 weeks after infection, respectively. Fifty per cent of the mice died during the fifth month after infection. Treatment with PR ointment twice daily for only 10 days was not sufficient to eliminate all of the parasites, although an improvement was noted. After 20 days of treatment, parasites were no longer detectable in the area of the lesions in all of the infected animals, and open lesions completely healed within a period of 3040 days (Fig. 3, Table 2). PR ointment was only slightly less effective against L. major infection in Balb/c mice (Table 2). After 20 days treatment, parasites were still found to be present in the lesions, However, the parasites were undetectable 20 days after termination of treatment.
EVANS
and L. WEIN~~~~H
that each new batch of PR should be examined against Leishmania both in vitro in tissue culture and in viva in experimental animals prior to its application to clinical study. PR is considered effective only if (a) PR at IO ~16 amastigotes ml-’ totally eliminates the intracellular from infected macrophages within 4 days of exposure to thedrug, and (b) ISi 12 PR ointment applied twice daily to the CL lesion caused by L. major in Balb/c mice cured the lesion after 6 days treatment. Indeed, with a new batch of PR recently received, 610 days treatment with PR ointment was sufficient to eliminate all of the L. muicano and L. ~ra~~~~e~~~ parasites from the CL lesions. Based on the results obtained in this study, a clinical trial with PR ointment has recently been started in Belize. Preliminary results indicate a high efficacy of PR ointment against both I!,. mexicana and L. braziliensis. Final results of the clinical study will be published elsewhere.
DISCUSSION
Identification of the leishmanial strains is generally carried out by either EF-serotyping, isoenzyme analysis or DNA hybridization (Chang & Bray, 1985). In this study, an attempt was made to use simple techniques and simple facilities for parasite identification. Three techniques were used to identify the Belizian isolates: the microagglutination test, EFserotyping and isoenzyme analysis. The microagglutination test that was recently found to be highly indicative in visceral leishmaniasis (Harith, Kolk, Leeuwenburg, Muigai, Huigen, Jelsma & Kagar, 1988) and CL (Mengistu, Kiessling & Akuffo, 1990), and the EF-serotyping proved to be only partially effective in identifying the Belizian leishmanial isolates. However, the isoenzyme analysis was shown to be a highly reliable and reproducible method for distinguishing leishmanial species. The Belizian L. mexicana strains were found to be highly susceptible to PR treatment showing 85% inhibition of promastigote growth within 4 days of exposure to PR at 100 pg ml-‘. Topical treatment of Belizian L. mexicana lesions in mice was also highly effective. Although 1Odays treatment was not sufficient to eliminate all of the parasites from the lesions, total elimination was achieved at the end of 20 days treatment. The results obtained with the Belizian strains were even better than those obtained with the L. major strain. In our previous study (El-On et al.. 1984) 6 days of treatment were sufficient to cure the CL (L. major) lesions in Balb/c mice, while in the present study, even 20 days treatment did not totally eliminate t. major parasites. An intensive study made recently irz vitro on cultivated infected macrophages and in vivo in infected Balb/c mice revealed that the PR batch received was not as effective as the original batch received several years ago. We have recently learned
Acknowledgements--This study was supported by the AIDCDR Grant No. DPE-5544-G-SS-7047-00. Paromomycin sulphate was kindly supplied by Parke Davis Warner Lambert, Italy and Farmitalia. Carlo Erba. Italy. REFERENCES ADLER S., FONER A.
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DLwrr.rt~.r.
Vol. I, ~i.~hr~zu~i~~~.~.Elsevier, Amsterdam. EL-ON J., JACOBS G. P., WITZT~M E. & GREENBLATTC. L. 1984. The development of topical treatment for cutaneous leishmaniasis due to Leishmania major in experimental
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rlgents Chemothcrap.v P. & WEINRAI.CH L.
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26: 745-75
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D. A.,
LANXN
S.
M.,
BALDWIN C. 1. & PETERS W.
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agglutination
test for
fieid
studies
of
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visceral
leishman~~is. ~~~~r~u~ ~~C~~~j~u~ ~ic~~b~~~~~~ 26: 132 1-I 325. LAINS~N R.
& STKANGWAYS-DIXON J. 1963. L~ishmu~iu mexicana: the epidemiology of dermal leishmaniasis in British Honduras. Transactions of the Royul Society of Tropical Medicine and Hygiene 51: 242-265. MI~N~ISTUG.. KIESSLINOR. &AK~FFoH. 1990. Thevalue ofa direct agglutination test in the diagnosis of cutaneous and
Treatment
of Belizian cutaneous
visceral leishmaniasis in Ethiopia. Transacfions of the Royal Society of Tropical Medicine and Hygiene 84: 359-362. SCHNURL. R., ZUCKERMANA. & GREENBLATTC. L. 1972.
leishmaniasis
127
Leishmanial serotypes as distinguished by the gel diffusion of factors excreted in vitro and in vivo. Israel Journal of Medical Sciences 8: 932-942.