Displaying publications 1 - 20 of 113 in total

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  1. ALEXANDER AD, WETMORE PW, EVANS LB, JEFFRIES H, GLEISER CA
    Am J Trop Med Hyg, 1955 May;4(3):492-506.
    PMID: 14376775
    Matched MeSH terms: Leptospira*
  2. ALEXANDER AD, EVANS LB, TOUSSAINT AJ, MARCHWICKI RH, McCRUMB FR
    Am J Trop Med Hyg, 1957 Sep;6(5):871-89.
    PMID: 13470208
    Matched MeSH terms: Leptospira*; Leptospirosis/immunology*
  3. Md-Lasim A, Mohd-Taib FS, Abdul-Halim M, Mohd-Ngesom AM, Nathan S, Md-Nor S
    PMID: 34502012 DOI: 10.3390/ijerph18179411
    Pathogenic Leptospira is the causative agent of leptospirosis, an emerging zoonotic disease affecting animals and humans worldwide. The risk of host infection following interaction with environmental sources depends on the ability of Leptospira to persist, survive, and infect the new host to continue the transmission chain. Leptospira may coexist with other pathogens, thus providing a suitable condition for the development of other pathogens, resulting in multi-pathogen infection in humans. Therefore, it is important to better understand the dynamics of transmission by these pathogens. We conducted Boolean searches of several databases, including Google Scholar, PubMed, SciELO, and ScienceDirect, to identify relevant published data on Leptospira and coinfection with other pathogenic bacteria. We review the role of the host-microbiota in determining the synanthropic interaction of Leptospira sp. with other bacteria, thus creating a suitable condition for the leptospira to survive and persist successfully. We also discuss the biotic and abiotic factors that amplify the viability of Leptospira in the environment. The coinfection of leptospira with pathogenic bacteria has rarely been reported, potentially contributing to a lack of awareness. Therefore, the occurrence of leptospirosis coinfection may complicate diagnosis, long-lasting examination, and mistreatment that could lead to mortality. Identifying the presence of leptospirosis with other bacteria through metagenomic analysis could reveal possible coinfection. In conclusion, the occurrence of leptospirosis with other diseases should be of concern and may depend on the success of the transmission and severity of individual infections. Medical practitioners may misdiagnose the presence of multiple infections and should be made aware of and receive adequate training on appropriate treatment for leptospirosis patients. Physicians could undertake a more targeted approach for leptospirosis diagnosis by considering other symptoms caused by the coinfected bacteria; thus, more specific treatment could be given.
    Matched MeSH terms: Leptospira*
  4. Philip N, Neela VK
    Cryobiology, 2022 Dec;109:89-93.
    PMID: 36179819 DOI: 10.1016/j.cryobiol.2022.09.007
    Leptospires are preserved by frequent sub-culturing in semisolid media due to the challenge of low recovery by freezing or liquid nitrogen methods. The present study evaluated three liquid EMJH medium compositions (Medium A: Leptospira medium base EMJH, Leptospira enrichment EMJH, 5-fluorouracil (3%), rabbit serum (1%) and calf serum (1%); Medium B: same as Medium A but without 5-fluorouracil; Medium C: same as Medium B but with the addition of sodium pyruvate) for the revival of leptospires after storage at -80 °C. A total of 18 Leptospira serovars cultured in Medium A was aliquoted into cryogenic vials and directly stored at -80 °C. A hundred microlitre from each serovar culture stored at -80 °C was sub-cultured on a selected time over a period of 30 months into Media A, B and C. Regrowth on Media B and C showed a better and faster recovery (89-100%) (p-value <0.05) compared to Medium A (67-100%). Leptospires can be stored longer at -80 °C and a good recovery could be obtained when sub-cultured on EMJH medium without 5-fluorouracil.
    Matched MeSH terms: Leptospira*
  5. Yeoh TS, Tang TH, Citartan M
    Biotechnol J, 2023 Mar;18(3):e2200418.
    PMID: 36426669 DOI: 10.1002/biot.202200418
    Leptospirosis is a potentially life-threatening zoonosis caused by pathogenic Leptospira and for rapid diagnostics, direct detection is desirable. LipL32 protein is the most suitable biomarker for direct detection. DNA aptamers are sought to be generated against LipL32 by Systemic Evolution of Ligands via Exponential Enrichment (SELEX). LepDapt-5a is the most potent aptamer candidate among all the candidates, as determined by direct Enzyme-linked Aptasorbent Assay (ELASA). LepDapt-5a was predicted to form a G-quadruplex structure as predicted by QGRS Mapper and validated experimentally by direct ELASA. The diagnostic potential of the aptamer was further tested on a direct and sandwich ELASA platform. A LOD of 106 mL-1 and 105 mL-1 were estimated by direct and sandwich ELASA platforms, respectively, which are within the range associated with leptospiremia levels. The dot blot assay developed was able to attain a LOD of 104 CFU mL-1 against pathogenic Leptospira, which is also within the leptospiremia level. This is the first-ever DNA aptamer and hybrid-heterodimeric aptamer constructed against LipL32. The diagnostic potentiality of the LepDapt-5a DNA aptamer was proven on three major diagnostic platforms, which are direct ELASA, sandwich ELASA, and aptamer-based dot assay.
    Matched MeSH terms: Leptospira/isolation & purification
  6. Philip N, Garba B, Neela VK
    Appl Microbiol Biotechnol, 2018 Jul;102(13):5427-5435.
    PMID: 29736823 DOI: 10.1007/s00253-018-9047-9
    Preservation of leptospiral cultures is tantamount to success in leptospiral diagnostics, research, and development of preventive strategies. Each Leptospira isolate has imperative value not only in disease diagnosis but also in epidemiology, virulence, pathogenesis, and drug development studies. As the number of circulating leptospires is continuously increasing and congruent with the importance to retain their original characteristics and properties, an efficient long-term preservation is critically needed to be well-established. However, the preservation of Leptospira is currently characterized by difficulties and conflicting results mainly due to the biological nature of this organism. Hence, this review seeks to describe the efforts in developing efficient preservation methods, to discover the challenges in preserving this organism and to identify the factors that can contribute to an effective long-term preservation of Leptospira. Through the enlightenment of the previous studies, a potentially effective method has been suggested. The article also attempts to evaluate novel strategies used in other industrial and biotechnological preservation efforts and consider their potential application to the conservation of Leptospira spp.
    Matched MeSH terms: Leptospira/growth & development; Leptospira/physiology*
  7. Alexander AD, Evans LB, Baker MF, Baker HJ, Ellison D, Marriapan M
    Appl Microbiol, 1975 Jan;29(1):30-3.
    PMID: 1110490
    Pathogenic leptospiras (1,424) isolated from natural waters and wet soils in Malaysia comprised 29 different serovars (synonym serotypes). All except two of the serovars had been found previously in Malaysia. The exceptional serovars were werrasingha, an Autumnalis serogroup member originally isolated in Ceylon, and a new serovar designated evansi. Serovar evansi had serological affinities with serovar ranarum which was isolated from the kidney of a frog in Iowa. The large variety of serovars found in jungle areas was consistent with similar previous findings of diverse serovar infections in troops who had operated in Malaysian jungles.
    Matched MeSH terms: Leptospira/classification*; Leptospira/isolation & purification; Leptospira/pathogenicity
  8. Benacer D, Zain SNM, Lewis JW, Khalid MKNM, Thong KL
    Rev Soc Bras Med Trop, 2017 Mar-Apr;50(2):239-242.
    PMID: 28562762 DOI: 10.1590/0037-8682-0364-2016
    INTRODUCTION:: This study aimed to develop a duplex endpoint PCR assay for rapid detection and differentiation of Leptospira strains.

    METHODS:: Primers were designed to target the rrs (LG1/LG2) and ligB (LP1/LP2) genes to confirm the presence of the Leptospira genus and the pathogenic species, respectively.

    RESULTS:: The assay showed 100% specificity against 17 Leptospira strains with a limit of detection of 23.1pg/µl of leptospiral DNA and sensitivity of 103 leptospires/ml in both spiked urine and water.

    CONCLUSIONS:: Our duplex endpoint PCR assay is suitable for rapid early detection of Leptospira with high sensitivity and specificity.
    Matched MeSH terms: Leptospira/classification*; Leptospira/genetics; Leptospira/isolation & purification
  9. Amran F, Mohd Khalid MK, Mohamad S, Mat Ripen A, Ahmad N, Goris MG, et al.
    Genome Announc, 2016;4(5).
    PMID: 27609924 DOI: 10.1128/genomeA.00956-16
    Leptospira interrogans serovar Bataviae was recently identified as one of the persistent Leptospira serovars in Malaysia. Here, we report the draft genome sequence of the L. interrogans serovar Bataviae strain LepIMR 22 isolated from kidney of a rodent in Johor, Malaysia.
    Matched MeSH terms: Leptospira; Leptospira interrogans
  10. Cheah HL, Ahmed SA, Tang TH
    World J Microbiol Biotechnol, 2023 Feb 21;39(4):104.
    PMID: 36808011 DOI: 10.1007/s11274-023-03540-4
    Leptospirosis is an emerging zoonotic disease caused by bacterial species of the genus Leptospira. However, the regulatory mechanisms and pathways underlying the adaptation of pathogenic and non-pathogenic Leptospira spp. in different environmental conditions remain elusive. Leptospira biflexa is a non-pathogenic species of Leptospira that lives exclusively in a natural environment. It is an ideal model not only for exploring molecular mechanisms underlying the environmental survival of Leptospira species but also for identifying virulence factors unique to Leptospira's pathogenic species. In this study, we aim to establish the transcription start site (TSS) landscape and the small RNA (sRNA) profile of L. biflexa serovar Patoc grown to exponential and stationary phases via differential RNA-seq (dRNA-seq) and small RNA-seq (sRNA-seq) analyses, respectively. Our dRNA-seq analysis uncovered a total of 2726 TSSs, which are also used to identify other elements, e.g., promoter and untranslated regions (UTRs). Besides, our sRNA-seq analysis revealed a total of 603 sRNA candidates, comprising 16 promoter-associated sRNAs, 184 5'UTR-derived sRNAs, 230 true intergenic sRNAs, 136 5'UTR-antisense sRNAs, and 130 open reading frame (ORF)-antisense sRNAs. In summary, these findings reflect the transcriptional complexity of L. biflexa serovar Patoc under different growth conditions and help to facilitate our understanding of regulatory networks in L. biflexa. To the best of our knowledge, this is the first study reporting the TSS landscape of L. biflexa. The TSS and sRNA landscapes of L. biflexa can also be compared with its pathogenic counterparts, e.g., L. borgpetersenii and L. interrogans, to identify features contributing to their environmental survival and virulence.
    Matched MeSH terms: Leptospira*
  11. Rosli MZ, Mohd-Taib FS, Khoo JJ, Chee HY, Wong YP, Shafie NJ, et al.
    Ecohealth, 2023 Jun;20(2):208-224.
    PMID: 37103759 DOI: 10.1007/s10393-023-01637-8
    Leptospirosis is a major zoonotic disease, especially in the tropics, and rodents were known to be carriers of this bacterium. There was established information on Leptospira prevalence among animal reservoirs in human-dominated landscapes from previous literature. However, there was very little focus given comparing the prevalence of Leptospira in a wide range of habitats. An extensive sampling of small mammals from various landscapes was carried out, covering oil palm plantations, paddy fields, recreational forests, semi-urbans, and wet markets in Peninsular Malaysia. This study aims to determine the prevalence of pathogenic Leptospira in a diversity of small mammals across different landscapes. Cage-trapping was deployed for small mammals' trappings, and the kidneys of captured individuals were extracted, for screening of pathogenic Leptospira by polymerase chain reaction (PCR) using LipL32 primer. Eight microhabitat parameters were measured at each study site. Out of 357 individuals captured, 21 (5.9%) were positive for pathogenic Leptospira of which recreational forest had the highest prevalence (8.8%) for landscape types, whereas Sundamys muelleri shows the highest prevalence (50%) among small mammals' species. Microhabitat analysis reveals that rubbish quantity (p Leptospira prevalence among small mammals. Furthermore, nMDS analysis indicates that the presence of faeces, food waste, and exposure to humans in each landscape type also were linked with high prevalence of pathogenic Leptospira among the small mammals. This study supplements previous studies on pathogenic Leptospira prevalence across different landscape types, and the major microhabitat factors associated with Leptospira prevalence. This information is crucial for epidemiological surveillance and habitat management to curb the possibility of the disease outbreaks.
    Matched MeSH terms: Leptospira*
  12. Pérolat P, Grimont F, Regnault B, Grimont PA, Fournié E, Thevenet H, et al.
    Res. Microbiol., 1990 Feb;141(2):159-71.
    PMID: 2189169
    A total of 67 serovar reference strains and 7 isolates belonging to the genus Leptospira were characterized by ribosomal ribonucleic acid (rRNA) gene restriction patterns. Fifty patterns were observed. Strains belonging to different genomic species always gave different patterns. However, genomic species were subdivided into several patterns. Forty-three serovars gave a specific pattern. Some serovars could not be separated by rRNA gene restriction patterns: strains of serovars icterohaemorrhagiae, copenhageni, lai, pyrogenes and jalna gave pattern 1; serovars birkini, mankarso and wolffi gave pattern 4; serovars canicola, gem, hebdomadis, pomona and hardjo (strain hardjoprajitno) gave pattern 12; serovars valbuzzi and zanoni gave pattern 14; serovars jonsis, malaya and sumneri gave pattern 16; serovars arborea, ballum, castellonis and kenya gave pattern 35; and serovars borincana and shermani gave pattern 43. These data provide the bases for a molecular typing system for the genus Leptospira.
    Matched MeSH terms: Leptospira/classification*; Leptospira/genetics; Leptospira interrogans/classification; Leptospira interrogans/genetics
  13. Vincent AT, Schiettekatte O, Goarant C, Neela VK, Bernet E, Thibeaux R, et al.
    PLoS Negl Trop Dis, 2019 05;13(5):e0007270.
    PMID: 31120895 DOI: 10.1371/journal.pntd.0007270
    The causative agents of leptospirosis are responsible for an emerging zoonotic disease worldwide. One of the major routes of transmission for leptospirosis is the natural environment contaminated with the urine of a wide range of reservoir animals. Soils and surface waters also host a high diversity of non-pathogenic Leptospira and species for which the virulence status is not clearly established. The genus Leptospira is currently divided into 35 species classified into three phylogenetic clusters, which supposedly correlate with the virulence of the bacteria. In this study, a total of 90 Leptospira strains isolated from different environments worldwide including Japan, Malaysia, New Caledonia, Algeria, mainland France, and the island of Mayotte in the Indian Ocean were sequenced. A comparison of average nucleotide identity (ANI) values of genomes of the 90 isolates and representative genomes of known species revealed 30 new Leptospira species. These data also supported the existence of two clades and 4 subclades. To avoid classification that strongly implies assumption on the virulence status of the lineages, we called them P1, P2, S1, S2. One of these subclades has not yet been described and is composed of Leptospira idonii and 4 novel species that are phylogenetically related to the saprophytes. We then investigated genome diversity and evolutionary relationships among members of the genus Leptospira by studying the pangenome and core gene sets. Our data enable the identification of genome features, genes and domains that are important for each subclade, thereby laying the foundation for refining the classification of this complex bacterial genus. We also shed light on atypical genomic features of a group of species that includes the species often associated with human infection, suggesting a specific and ongoing evolution of this group of species that will require more attention. In conclusion, we have uncovered a massive species diversity and revealed a novel subclade in environmental samples collected worldwide and we have redefined the classification of species in the genus. The implication of several new potentially infectious Leptospira species for human and animal health remains to be determined but our data also provide new insights into the emergence of virulence in the pathogenic species.
    Matched MeSH terms: Leptospira/classification*; Leptospira/genetics; Leptospira/isolation & purification; Leptospira/pathogenicity*
  14. Rao M, Amran F, Kamaruzaman AA, Hakim Esa HA, Abdul Hameed A, Mohamed Shabery NA
    Am J Trop Med Hyg, 2021 01;104(1):216-218.
    PMID: 33289472 DOI: 10.4269/ajtmh.20-0267
    Leptospirosis is an important zoonotic disease with worldwide distribution and nonspecific clinical manifestation. We report a case of fatal leptospirosis in a previously healthy woman with a causative agent. A young adult Indian woman was brought in dead to the forensic department. Ten days before, she developed fever, dizziness with headache, myalgia, diarrhea, and vomiting. Routine inquest and autopsy were performed on the deceased, revealing hemorrhagic lungs with extensive intra-alveolar hemorrhages, pale liver with dissociation and separation of hepatocyte plates, and edematous brain with histiocyte and lymphocyte infiltration in the parenchyma and meninges. Heart tissue depicts myocarditis and pericarditis inflammatory changes. Cerebrospinal fluid (CSF) was turbid in appearance with mildly elevated leukocytes, predominantly lymphocytes. Real-time PCR targeting lipL32 gene of pathogenic Leptospira was detected in the blood, CSF, brain, kidney, heart, and liver. The genetic profile of the causative agent was ST149 (multi-locus sequence typing Scheme 3). This study illustrates the usefulness of Leptospira PCR assay in postmortem diagnosis and addresses the need for further surveillance to identify the epidemiological link of the disease.
    Matched MeSH terms: Leptospira interrogans/classification; Leptospira interrogans/genetics*
  15. Mohamed-Hassan SN, Bahaman AR, Mutalib AR, Khairani-Bejo S
    Trop Biomed, 2010 Apr;27(1):30-2.
    PMID: 20562810 MyJurnal
    One hundred and sixty eight rats were trapped from the National Service Training Centres (NSTC) in Kelantan and Terengganu from October 2008 to May 2009. Microscopic agglutination test (MAT) was performed to detect the presence of agglutinating antibodies to Leptospira among the rats caught. All the MAT positive rats were identified as Rattus tiomanicus. In Kelantan, 17.3 % (14/81) of the rats had leptospiral antibodies to serovars Icterohaemorrhagiae (12.3%), Canicola (2.5%), Ballum (1.2%), and Pyrogenes (1.2%). In Terengganu, 18.4% (16/87) of the rats had antibodies to serovars Icterohaemorrhagiae (15%), Canicola (1.1%), Pyrogenes (1.1%) and Hebdomadis (1.1%). This study indicated that Leptospira serovars were prevalent in the rat population in the study areas and could be a source of infection to humans. Therefore, control of the rat population in all NSTC is critical to prevent outbreaks of leptospirosis amongst the NSTC trainees.
    Matched MeSH terms: Leptospira/classification; Leptospira/isolation & purification
  16. Azhari NN, Ramli SNA, Joseph N, Philip N, Mustapha NF, Ishak SN, et al.
    Acta Trop, 2018 Dec;188:68-77.
    PMID: 30145261 DOI: 10.1016/j.actatropica.2018.08.020
    Leptospirosis is caused by the spirochetal bacterium Leptospira of which rodents are considered the most important reservoir. This study aims to determine and characterize virulent Leptospira species among rodents and small mammals found in human settlements and recreational spots within the Hulu Langat and Gombak districts of Selangor, Malaysia; regions that frequently report probable human leptospirosis cases. Molecular analysis revealed an overall Leptospira detection rate of 14.3% among the 266 small mammals captured, and the human settlements were found to have the highest number of isolates (15.1%), followed by recreational sites (14.5%). The molecular characterization conducted based on the lipL32, secY genes and MLST revealed that the strains belonged to four different species, including; Leptospira interrogans (29; 76.3%; ST50, ST238, ST243), L. kirschneri (5; 13.15%; ST110), L. borgpetersenii (3; 8%; ST143) and L. weilii (1; 2.63%; ST242). The study revealed genotypes of circulating strains among small mammals in Malaysia, which include Leptospira locus ST110 L. kirschneri, ST 50 L. interrogans, ST143 L. borgpetersenii and ST242 L. weilii. Among the small mammals studied, 17/105 (16.2%) Rattus norvegicus, 7/59 (11.9%) of Rattus rattus, 5/24 (20.8%) of Maxomys whiteheadi, 4/18 (22.2%) of Sundamys muelleri, 2/22 (9%), Tupaia gliss, 2/16 (12.5%) Rattus tiomanicus and 1/4 (25%) of Suncus murinus carried pathogenic leptospires. The data from the present study may imply that, in addition to rodents, other small mammals also serve as maintenance hosts for Leptospira. Hence, much remains unknown about Leptospira maintenance hosts, and there is need for further investigation to ascertain the prevailing serovars of pathogenic Leptospira in Malaysia. This will assist in the development of efficient diagnostic assays with improved microscopic agglutination test (MAT) panels, and in the implementation of suitable prevention and control measures.
    Matched MeSH terms: Leptospira/genetics*; Leptospira/isolation & purification
  17. Bahaman AR, Ibrahim AL
    Vet Rec, 1986 Sep 27;119(13):325-6.
    PMID: 3776042
    Matched MeSH terms: Leptospira/immunology; Leptospira/isolation & purification; Leptospira interrogans serovar canicola/immunology; Leptospira interrogans serovar canicola/isolation & purification
  18. Mohamad Safiee AW, Ali MRM, Fauzi MH, Besari AM, Yean CY, Neela VK, et al.
    PMID: 32085530 DOI: 10.3390/ijerph17041307
    Objectives: Isolation of Leptospira by culture represents a definitive growth and confirmation of the disease, yet it is hampered with its nature of slow growth. With slight modification of culture method, the study aims to isolate and characterize Leptospira spp. from patients with acute febrile illness. Methods: A total of 109 blood samples were collected from patients with acute febrile illness that presented at the Emergency Department of Hospital Universiti Sains Malaysia, Malaysia. Clinical samples were subjected to Leptospira IgM Rapid test, microscopic agglutination test (MAT), isolation by culture method, and direct real-time PCR test. For leptospiral isolation, the samples (whole blood and deposit from spun plasma) were cultured into modified Ellinghausen McCullough Johnson Harris (EMJH) media with and without 5'-fluorouracil (5-FU). In every culture positive sample, partial 16S rRNA gene sequencing was performed for molecular identification of the isolates. Phylogenetic analysis was carried out to determine the genetic relatedness among the isolates. An inhibition of 5-FU study was performed on Leptospirainterrogans serovar Canicola with different concentrations to compare the growth detection of the tested Leptospira with or without 5-FU within 7 days of incubation. Results: Leptospirosis was diagnosed in 14.7% of patients with acute febrile illness. Two Leptospira spp. (n = 2/109, 1.85%) were successfully isolated from whole blood and deposit from spun plasma samples. B004 and B208 samples were positive at day 11 and day 7, respectively, in EMJH media without addition of 5-FU. Sample B004 was identified as Leptospira interrogans and B208 as Leptospira weilli. Phylogenetic analysis confirmed that both of them were within pathogenic group and they were not related. The 5-FU inhibition study revealed that additional of 5-FU at final concentration of 200 µg/mL to EMJH media demonstrated an inhibitory effect on the growth of the tested strain Conclusion: Isolation of Leptospira spp. using EMJH media without addition of 5'-fluorouracil resulted in a better outcome. Two pathogenic Leptospira isolates were successfully cultivated from patients with acute febrile illness that were genetically not related.
    Matched MeSH terms: Leptospira/isolation & purification*
  19. Mohd Hanapi IR, Sahimin N, Maackara MJB, Annisa AS, Abdul Mutalib RNS, Lewis JW, et al.
    BMC Infect Dis, 2021 Nov 01;21(1):1128.
    PMID: 34724919 DOI: 10.1186/s12879-021-06830-0
    BACKGROUND: Refugees in Malaysia, who are afflicted by poverty, conflict and poor health, are vulnerable to a range of zoonotic infections in the deprived environmental and social conditions under which they live. Exposure to infections such as leptospirosis, for which rodents are primary hosts, is of particular concern.

    METHODS: A wellness program was conducted to determine the presence of antibodies against Leptospira (seroprevalence) in 11 refugee community schools and centers in the Klang Valley, Malaysia. A total of 433 samples were assessed for IgG and IgM antibodies against Leptospira, using enzyme-linked immunosorbent assays (ELISA).

    RESULTS: Overall Leptospira seroprevalence was 24.7%, with 3.0% being seropositive for anti-Leptospira IgG and 21.7% for anti-Leptospira IgM. Factors significantly associated with overall Leptospira seroprevalence included: age, ethnicity, pet ownership, knowledge of disease and awareness of disease fatality. For IgM seroprevalence, significant risk factors included sex, ethnicity, eating habits with hands, pet ownership, the presence of rats, walking in bare feet and water recreation visits.

    CONCLUSIONS: These findings highlight the need for improvements in health and well-being among the refugee community through disease awareness programs and provision of healthy behavior programs, particularly in hygiene and sanitation through community engagement activities.

    Matched MeSH terms: Leptospira*
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