In JoVE (1)

Other Publications (12)

Articles by Jorge Coronel in JoVE

Other articles by Jorge Coronel on PubMed

Antimicrobial Susceptibilities and Serotype Distribution of Streptococcus Pneumoniae Isolates from a Low Socioeconomic Area in Lima, Peru

Clinical and Diagnostic Laboratory Immunology. Nov, 2002  |  Pubmed ID: 12414769

Streptococcus pneumoniae isolates were obtained from nasopharyngeal swabs taken from children living in a low socioeconomic area of Lima, Peru, to determine the rates of antimicrobial resistance and serotype distribution. A total of 146 nasopharyngeal isolates were collected from children from 3 to 38 months of age. Twenty-one clinical laboratory isolates from both sterile and nonsterile sites were obtained from a local hospital. Isolates with reduced susceptibilities to penicillin represented 15.1 and 42.9% of the nasopharyngeal and clinical isolates, respectively. For neither group of isolates did penicillin MICs exceed 1.5 micro g/ml, indicating only intermediate resistance. Thirty-two different serotypes were identified from the 146 nasopharyngeal isolates. The serotypes of the clinical isolates were represented among those 32 types. Isolates with reduced susceptibility to multiple antimicrobial agents were present in both settings. These findings indicate some of the highest rates of antimicrobial resistance in the region as well as a slightly different serotype distribution pattern from those of other South American countries. The 7-valent conjugate pneumococcal vaccines would only have a limited effect, providing coverage for about half of all isolates. Increasing rates of resistance in Peru necessitate an awareness of antimicrobial treatment practices and vaccination strategies.

Infrequent MODS TB Culture Cross-contamination in a High-burden Resource-poor Setting

Diagnostic Microbiology and Infectious Disease. Sep, 2006  |  Pubmed ID: 16678991

One obstacle to wider use of rapid liquid culture-based tuberculosis diagnostics such as the microscopic observation drug susceptibility (MODS) assay is concern about cross-contamination. We investigated the rate of laboratory cross-contamination in MODS, automated MBBacT, and Lowenstein-Jensen (LJ) cultures performed in parallel, through triangulation of microbiologic (reculturing stored samples), molecular (spoligotype/RFLP), and clinical epidemiologic data. At least 1 culture was positive for Mycobacterium tuberculosis for 362 (11%) of 3416 samples; 53 were regarded as potential cross-contamination suspects. Cross-contamination accounted for 17 false-positive cultures from 14 samples representing 0.41% (14/3416) and 0.17% (17/10248) of samples and cultures, respectively. Positive predictive values for MODS, MBBacT (bioMérieux, Durham, NC), and LJ were 99.1%, 98.7%, and 99.7%, and specificity was 99.9% for all 3. Low rates of cross-contamination are achievable in mycobacterial laboratories in resource-poor settings even when a large proportion of samples are infectious and highly sensitive liquid culture-based diagnostics such as MODS are used.

Microscopic-observation Drug-susceptibility Assay for the Diagnosis of TB

The New England Journal of Medicine. Oct, 2006  |  Pubmed ID: 17035648

New diagnostic tools are urgently needed to interrupt the transmission of tuberculosis and multidrug-resistant tuberculosis. Rapid, sensitive detection of tuberculosis and multidrug-resistant tuberculosis in sputum has been demonstrated in proof-of-principle studies of the microscopic-observation drug-susceptibility (MODS) assay, in which broth cultures are examined microscopically to detect characteristic growth.

Solar Disinfection of MODS Mycobacterial Cultures in Resource-poor Settings

PloS One. 2007  |  Pubmed ID: 17971863

Safe disposal of TB culture material in which the infectious burden of clinical samples has been greatly amplified is an important challenge in resource-limited settings. The bactericidal capacity of solar cookers has been demonstrated previously for conventional bacteria and contaminated clinical waste. We investigated the use of a simple solar cooker for the sterilization of mycobacterial broth cultures from the microscopic observation drug susceptibility assay (MODS).

Inter- and Intra-assay Reproducibility of Microplate Alamar Blue Assay Results for Isoniazid, Rifampicin, Ethambutol, Streptomycin, Ciprofloxacin, and Capreomycin Drug Susceptibility Testing of Mycobacterium Tuberculosis

Journal of Clinical Microbiology. Oct, 2008  |  Pubmed ID: 18701659

The intersample and intrasample variability of the results obtained with the microplate Alamar blue assay for the indirect drug susceptibility testing of Mycobacterium tuberculosis was investigated. Between 1.2 and 8.5% of paired MICs differed by more than one twofold dilution, resulting in discordant susceptible-resistant designations at frequencies between 0.6% (rifampin) and 18.9% (ethambutol).

Distribution Patterns, Population Status and Conservation of Melanosuchus Niger and Caiman Yacare (Crocodylia, Alligatoridae) in Oxbow Lakes of the Ichilo River Floodplain, Bolivia

Revista De Biología Tropical. Jun, 2008  |  Pubmed ID: 19256453

Caiman yacare (lagarto) and Melanosuchus niger (black caiman), sympatric species in the Bolivian Amazon basin, have been severely overexploited in the past. We present the results of a standardized survey of C. yacare and M. niger populations in order to evaluate their actual population status in twelve oxbow lakes of the Ichilo River floodplain. Additionally we explored the effect of environmental and anthropogenic variables on caiman distribution patterns. The average density of C yacare and M niger in the shoreline of floodplain lakes was of 6 and 1 ind/km, respectively. For both species, the population was composed mainly of juvenile individuals. We used regression tree analysis (RTA) to assess patterns of M. niger and C. yacare densities with eight environmental and two anthropogenic variables. The RTA analysis showed that the variation in the densities of both C. yacare (52.4%) and M. niger (36.8 %) was related to water conductivity. For C yacare, higher densities occurred at higher values of water conductivity, while M. niger densities followed an opposite trend, resulting in relatively well spatially segregated populations of the two species. After excluding conductivity, Lake-River Distance (LRD) was shown to be the main splitting variable in the RTA analysis. The observed distribution patterns may be the result of the historical post-hunting situation, in combination with differences in habitat selection by the two species, and competitive exclusion processes between the two species. M. niger, a species reported to be recovering slowly from previous low population levels, appears relatively well protected in the Ichilo river floodplain.

Can the Power of Mobile Phones Be Used to Improve Tuberculosis Diagnosis in Developing Countries?

Transactions of the Royal Society of Tropical Medicine and Hygiene. Jun, 2009  |  Pubmed ID: 19036392

The low-cost Microscopic Observation Drug Susceptibility (MODS) assay is a non-proprietary test that delivers rapid and accurate diagnosis of tuberculosis (TB) and multidrug-resistant TB. Although methodologically straightforward, implementation is challenging in isolated settings where personnel trained in plate reading are lacking. One affordable strategy to address this shortfall is the use of mobile phones, first to transmit images captured by an inverted microscope to a remote site where pattern recognition is performed by trained personnel, and second to receive the resulting output of this analysis. Such a system could be used for training of laboratory personnel through distance learning, resolution of equivocal appearances and quality assurance.

Field and Laboratory Preparedness: Challenges to Rolling out New Multidrug-resistant Tuberculosis Diagnostics

Revista Panamericana De Salud Pública = Pan American Journal of Public Health. Aug, 2009  |  Pubmed ID: 19814891

In a pilot implementation project of the microscopic-observation drug-susceptibility methodology, we conducted a process evaluation to identify health system and logistic challenges that need to be addressed in order to harness the benefits of rolling out promising new diagnostic tools for multidrug-resistant tuberculosis (MDRTB).

Microscopic Observation Drug Susceptibility Assay for Tuberculosis Screening Before Isoniazid Preventive Therapy in HIV-infected Persons

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America. Apr, 2010  |  Pubmed ID: 20192727

Active tuberculosis (TB) must be excluded before initiating isoniazid preventive therapy (IPT) in persons infected with human immunodeficiency virus (HIV), but currently used screening strategies have poor sensitivity and specificity and high patient attrition rates. Liquid TB culture is now recommended for the detection of Mycobacterium tuberculosis in individuals suspected of having TB. This study compared the efficacy, effectiveness, and speed of the microscopic observation drug susceptibility (MODS) assay with currently used strategies for TB screening before IPT in HIV-infected persons.

Development of Low-cost Inverted Microscope to Detect Early Growth of Mycobacterium Tuberculosis in MODS Culture

PloS One. 2010  |  Pubmed ID: 20351778

The microscopic observation drug susceptibility (MODS) assay for rapid, low-cost detection of tuberculosis and multidrug resistant tuberculosis depends upon visualization of the characteristic cording colonies of Mycobacterium tuberculosis in liquid media. This has conventionally required an inverted light microscope in order to inspect the MODS culture plates from below. Few tuberculosis laboratories have this item and the capital cost of $5,000 for a high-end microscope could be a significant obstacle to MODS roll-out.

Prolonged Infectiousness of Tuberculosis Patients in a Directly Observed Therapy Short-course Program with Standardized Therapy

Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America. Aug, 2010  |  Pubmed ID: 20624064

Effective tuberculosis control is compromised by a lack of clarity about the timeframe of viable Mycobacterium tuberculosis shedding after treatment initiation under programmatic conditions. This study quantifies time to conversion from smear and culture positivity to negativity in unselected tuberculosis patients receiving standardized therapy in a directly observed therapy short-course (DOTS) program.

Evaluation of Bleach-sedimentation for Sterilising and Concentrating Mycobacterium Tuberculosis in Sputum Specimens

BMC Infectious Diseases. 2011  |  Pubmed ID: 21985457

Bleach-sedimentation may improve microscopy for diagnosing tuberculosis by sterilising sputum and concentrating Mycobacterium tuberculosis. We studied gravity bleach-sedimentation effects on safety, sensitivity, speed and reliability of smear-microscopy.

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