Introduction: Acanthamoeba is an ubiquitous free-living protozoa which causes serious ocular problems. Acanthamoeba keratitis is becoming more prevalent amongst contact lens wearers. The disease can cause loss of vision and blindness if not treated properly. The objective of this research is to study the sensitivity of six Acanthamoeba spp. isolates, of which three were from the clinical isolates (HKL 95, HTH 40 and HS 6) and the remaining three from environmental isolates (TTT 9, TL 3 and SMAL 8) to antimicrobial agents. Methods: The antimicrobial agents chosen for this purpose were polyhexamethylene biguanide (PHMB) and chlorhexidine. Serial dilutions were perfomed for polyhexamethylene biguanide and chlorhexidine. Cyst suspensions from the chosen isolates were exposed to PHMB and chlorhexidine respectively. After 48 hours incubation time at 30°C, each mixture was filtered and filtration membrane was put onto non-nutrient agar laid with Escherichia coli. The agar plates were incubated for three days at 30°C and examined daily until day 14 to detect the presence of Acanthamoeba trophozoites under the inverted microscope. The presence of trophozoites indicated the ineffectiveness of the antimicrobial agents. Results: Both of the antimicrobial agents tested were found to be effective against Acanthamoeba cysts from all the test strains. Polyhexamethylene biguanide gave a minimum cysticidal concentration (MCC) mean value of 2.848 μg/mL while chlorhexidine showed
MCC mean value at a concentration of 3.988 μg/mL. Conlusion: It can be concluded that the Acanthamoeba cysts were sensitive to polyhexamethylene biguanide and chlorhexidine.
Acanthamoeba is a free-living protozoa which causes serious ocular problem. Acanthamoeba keratitis is becoming more prevalent amongst contact lens wearers and it can cause loss of vision and blindness if not treated properly. The objective of this research is to determine the effectiveness of gentamicin against six Acanthamoeba spp. isolates, of which three were clinical isolates (HS 6, HKL 95, HTH 73) and three environmental isolates (SMAL 7, SMAL 8, TTT 9). Cyst suspension from the chosen isolates were exposed to gentamicin. After 48 hours of incubation at temperature of 30°C and 37oC, each mixture was filtered and filtration membrane was put onto non-nutrient agar laid with Escherichia coli. The agar plates were incubated for three days at 30oC and 37oC and the plates were examined daily until day 14 to look for the presence of Acanthamoeba trophozoites under inverted microscope. The presence of trophozoites indicated the ineffectiveness of gentamicin. Gentamicin was found to be effective against Acanthamoeba cysts from all the test strains at both incubation temperatures. The minimum cysticidal concentration (MCC) mean value of gentamicin was 0.193 mg/mL at 30oC and 0.229 mg/mL at 37oC. So, we concluded that gentamicin has cysticidal potential towards Acanthamoeba.
Acanthamoeba spp. merupakan ameba hidup bebas yang biasa ditemui
di persekitaran. Ia merupakan agen penyebab keratitis Acanthamoeba (AK)
dan ensefalitis ameba bergranuloma (GAE). Ameba ini juga mampu menjadi
perumah kepada pelbagai bakteria termasuklah yang bersifat patogenik seperti
Mycobacterium, Legionella dan Staphylococcus aureus rintang metisilin (MRSA).
Berdasarkan maklumat ini, satu kajian dijalankan untuk mengesan kehadiran tiga
bakteria endosimbion berkepentingan perubatan di dalam Acanthamoeba spp. yang
telah dipencilkan dari bolong penghawa dingin yang terdapat di wad and dewan
bedah di Pusat Perubatan Universiti Kebangsaan Malaysia. Kehadiran bakteria
endosimbion ini disaring menggunakan pasangan primer khusus bagi setiap genus
menggunakan reaksi rantai polimerase (PCR) konvensional dan disahkan dengan
analisis penjujukan. Dua puluh sembilan (80.56%) pencilan Acanthamoeba spp.
didapati mengandungi bakteria endosimbion patogenik yang disasarkan dengan
sekurang-kurangnya satu genus bakteria bagi setiap pencilan. Mycobacterium
(82.76 %) adalah bakteria yang paling banyak dikesan, diikuti dengan Legionella sp.
(65.52 %) dan Pseudomonas spp. (62.07 %). Tiada bakteria MRSA dikesan daripada
mana-mana pencilan dalam kajian ini. Dua endosimbion Mycobacterium yang
dikenalpasti telah dikelompokkan ke dalam strain Mycobacterium tuberculosis.
Kami membuat kesimpulan bahawa, kebanyakan Acanthamoeba berpotensi untuk
menjadi perumah bagi pelbagai bakteria patogenik, namun implikasi interaksi ini
terhadap patogenisiti kedua-dua organisma masih kurang jelas dan memerlukan
penyelidikan yang lebih lanjut.
Acanthamoeba is a free-living amoeba and opportunistic protozoa that causes infection to humans. One of its primary infections is Acanthamoeba keratitis that occurs mostly amongst contact lens users. There are some difficulties in providing effective treatment to the patients as the cysts of Acanthamoeba spp. are very resistant towards most of the antimicrobial agents. Thus, study was conducted to determine the effectiveness of antimicrobial agents comprising 0.1% propamidine isethionate (Brolene®) and 0.3% ciprofloxacin (Ciloxan®) towards two clinical isolates of Acanthamoeba spp. (HUKM 74 and HS 72). Besides that, the minimum cysticidal concentration (MCC) of the tested antimicrobial agents were also determined. Propamidine isethionate and ciprofloxacin showed cysticidal activities at therapeutic dosage against both Acanthamoeba spp. isolates. The minimum cysticidal concentration for propamidine isethionate was between 62.5-125 µg/ml while for ciprofloxacin was 375 µg/ml. Both the clinical isolates of Acanthamoeba belonged to group II (Polyphagids).
Rhipicephalus (Boophilus) microplus serves as an important ectoparasite of livestock and a vector of several pathogens resulting in diseases, subsequently affecting the agricultural field as well as the economy. The extensive use of synthetic acaricides is known to cause resistance over time and therefore a much safer, effective and environmentally friendly alternative to overcome tick infestation should be implemented. Larval immersion tests (LIT) were done to evaluate the effects of Citrus hystrix (Family: Rutaceae) and Cymbopogon citratus (Family: Poaceae) essential oils (EOs) for their individual and combined (1:1) acaricidal activity against the cattle tick. Results showed that LC50 and LC90 values in 24 and 48 hours for Cit. hystrix EO were 11.98% and 24.84%, and 10.95% and 21.71% respectively. LC50 and LC90 values for Cym. citratus EO were 1.21% and 6.28%, and 1.05% and 6.12% respectively. The mixture of EOs from two plants in 1:1 ratio (Cit. hystrix 50%: Cym. citratus 50%) was found to exhibit antagonistic effect (synergistic factor < 1). The 24 hours and 48 hours LC50 and LC90 values for combined EOs were 1.52% and 2.84%, and 1.50% and 2.76% respectively. Individual and combined essential oils were subjected to qualitative analysis using gas chromatography-mass spectrometry (GC-MS) to screen the chemical components present in EOs. Our results showed that the combination of Cit. hystrix and Cym. citratus at 1:1 ratio resulted in an antagonistic effect and the use of Cym. citratus alone is more toxic to R. (B.) microplus, making it a better alternative to chemical based acaricide.
Is Acanthamoeba sp. normally found in the eyes? A study was carried out to establish the possibility of Acanthamoeba sp. as a part of the normal conjunctival flora. Conjunctiva swabbing were carried out in 286 healthy Orang Asli school children using sterile cotton swab. The swab was then inoculated onto non-nutrient agar (NN-A). Heat killed Escherichia coli that was used as food source for the growth of the amoebae was pipetted onto and away from the smear. The plates were incubated at 30 degrees C and examined daily using an inverted microscope for 14 days. Morphology of the trophozoites and cysts of the amoebae were used as the taxonomic criteria for identification. Positive-controls and negative-controls were done to check for the consistency of the technique used and monitoring of contamination respectively. None of the conjunctiva swab cultured was positive for Acanthamoeba sp. This finding may indicate that Acanthamoeba sp. is not part of normal conjunctival flora or conjunctiva swab is an insensitive technique to isolate the organism. However, a more extensive research is needed to investigate these possibilities.
Abstract. The species identification of Enterocytozoon bieneusi and Encephalitozoon intestinalis is only possible using transmission electron microscopy (TEM), mo lecular techniques and immunofluorescence antibody assays (IFA). In this study, 50 positive and 50 negative fecal specimens for microsporidial spores using the Weber modified trichrome (WMT) staining technique were examined using IFA-MAbs. Of the 100 specimens examined, the microsporidial spores identified by IFA-MAbs were Enterocytozoon Bieneusi 42 (75%) Encephalitozoon intestinalis 7 (12.5%) and mixed infections 7 (12.5%). The sensitivity and specificity of IFA-MAbs in detecting microsporidial spores were 98% and 86%, respectively. The agreement between the WMT staining technique and IFA-MAbs was statistically significant by Kappa statistics (K = 0.840; p < 0.001). E. bieneusi was the commonest Microsporidia species isolated from the studied population; the presence of microsporidial spores detected by IFA-MAbs should be confirmed by other methods.
An observational study was carried out to establish the existence of intestinal microsporidiosis among patients with and without gastrointestinal symptoms in Hospital Universiti Kebangsaan Malaysia, Malaysia. A total of 893 faecal specimens from hospitalized patients were examined for microsporidia using a modification of the usual Gram-chromotrope stain technique. One hundred and sixteen (13.0%) patients were positive for microsporidia: 84 (72.4%), 27 (23.3%) and 5 (4.3%) were low, moderate and high excreters of microsporidia spores, respectively. Of the 91 patients with available medical records, microsporidiosis was commonly observed in children aged 0-6 years (26.4%) and adults aged >or=31 years (57.2%). About one-third of this infection was observed in immunocompetent individuals. Among the immunosuppressive group, microsporidia were observed to be more prevalent in patients with haematological malignancy or a combination of malignancy and diabetes mellitus. About 74% of the patients who had microsporidia in their faeces had gastrointestinal symptoms, which could be related to infections or induced by immunosuppressive therapy. The role of microsporidia in causing gastrointestinal symptoms in this population is as yet unclear.
A serologic study of Toxoplasma antibodies among 501 foreign migrant workers in Malaysia was conducted in a plantation and detention camp. The highest prevalence rate of 46.2% was among Nepalese workers. Statistical analysis indicated the IgG positivity rate among local residents was significantly higher than the migrants studied (p < 0.05). The IgM positivity rate showed no significant difference between the two groups (p > 0.05). No significant difference in the prevalence rate was noted between the migrants and the local workers when grouped by agricultural and non-agricultural occupations (p > 0.05). The continuous introduction of these infections may influence the epidemiology and further compromise efforts in control and prevention. It is therefore important to monitor of non-notifiable diseases.