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Serological rapid diagnostic tests (RDTs) are widely used across pathologies, often providing users a simple, binary result (positive or negative) in as little as 5 to 20 min. Since the beginning of the COVID-19 pandemic, new RDTs for identifying SARS-CoV-2 have rapidly proliferated. However, these seemingly easy-to-read tests can be highly subjective, and interpretations of the visible "bands" of color that appear (or not) in a test window may vary between users, test models, and brands. We developed and evaluated the accuracy/performance of a smartphone application (xRCovid) that uses machine learning to classify SARS-CoV-2 serological RDT results and reduce reading ambiguities. Across 11 COVID-19 RDT models, the app yielded 99.3% precision compared to reading by eye. Using the app replaces the uncertainty from visual RDT interpretation with a smaller uncertainty of the image classifier, thereby increasing confidence of clinicians and laboratory staff when using RDTs, and creating opportunities for patient self-testing.
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Teste Sorológico para COVID-19 , COVID-19/diagnóstico , Aprendizado de Máquina , Aplicativos Móveis , SARS-CoV-2 , HumanosRESUMO
Numerous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid serological tests have been developed, but their accuracy has usually been assessed using very few samples, and rigorous comparisons between these tests are scarce. In this study, we evaluated and compared 10 commercially available SARS-CoV-2 rapid serological tests using the STARD (Standards for Reporting of Diagnostic Accuracy Studies) methodology. Two hundred fifty serum samples from 159 PCR-confirmed SARS-CoV-2 patients (collected 0 to 32 days after the onset of symptoms) were tested with rapid serological tests. Control serum samples (n = 254) were retrieved from pre-coronavirus disease (COVID) periods from patients with other coronavirus infections (n = 11), positivity for rheumatoid factors (n = 3), IgG/IgM hyperglobulinemia (n = 9), malaria (n = 5), or no documented viral infection (n = 226). All samples were tested using rapid lateral flow immunoassays (LFIAs) from 10 manufacturers. Only four tests achieved ≥98% specificity, with the specificities ranging from 75.7% to 99.2%. The sensitivities varied by the day of sample collection after the onset of symptoms, from 31.7% to 55.4% (days 0 to 9), 65.9% to 92.9% (days 10 to 14), and 81.0% to 95.2% (>14 days). Only three of the tests evaluated met French health authorities' thresholds for SARS-CoV-2 serological tests (≥90% sensitivity and ≥98% specificity). Overall, the performances varied greatly between tests, with only one-third meeting acceptable specificity and sensitivity thresholds. Knowledge of the analytical performances of these tests will allow clinicians and, most importantly, laboratorians to use them with more confidence; could help determine the general population's immunological status; and may help diagnose some patients with false-negative real-time reverse transcription-PCR (RT-PCR) results.
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Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , Testes Diagnósticos de Rotina/normas , SARS-CoV-2/isolamento & purificação , Anticorpos Antivirais/sangue , COVID-19/sangue , COVID-19/patologia , Testes Diagnósticos de Rotina/métodos , Feminino , Humanos , Imunoensaio , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Guias de Prática Clínica como Assunto , Estudos Retrospectivos , SARS-CoV-2/imunologia , Sensibilidade e EspecificidadeRESUMO
We report evaluation of 30 assays' (17 rapid tests (RDTs) and 13 automated/manual ELISA/CLIA assay (IAs)) clinical performances with 2594 sera collected from symptomatic patients with positive SARS-CoV-2 rRT-PCR on a respiratory sample, and 1996 pre-epidemic serum samples expected to be negative. Only 4 RDT and 3 IAs fitted both specificity (> 98%) and sensitivity (> 90%) criteria according to French recommendations. Serology may offer valuable information during COVID-19 pandemic, but inconsistent performances observed among the 30 commercial assays evaluated, which underlines the importance of independent evaluation before clinical implementation.
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Anticorpos Antivirais/sangue , Teste Sorológico para COVID-19/métodos , COVID-19/sangue , Imunoensaio/métodos , SARS-CoV-2/imunologia , COVID-19/virologia , Humanos , Imunoensaio/economia , Imunoglobulina M/sangue , Kit de Reagentes para Diagnóstico , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificação , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: War-wounded civilians in Middle East countries are at risk of post-traumatic osteomyelitis (PTO). We aimed to describe and compare the bacterial etiology and proportion of first-line antibiotics resistant bacteria (FLAR) among PTO cases in civilians from Syria, Iraq and Yemen admitted to the reconstructive surgical program of Médecins Sans Frontières (MSF) in Amman, Jordan, and to identify risk factors for developing PTO with FLAR bacteria. METHODS: We retrospectively analyzed the laboratory database of the MSF program. Inclusion criteria were: patients from Iraq, Yemen or Syria, admitted to the Amman MSF program between October 2006 and December 2016, with at least one bone biopsy sample culture result. Only bone samples taken during first orthopedic surgery were included in the analysis. To assess factors associated with FLAR infection, logistic regression was used to estimate odds ratio (ORs) and 95% confidence intervals (CI). RESULTS: 558 (76.7%) among 727 patients included had ≥1 positive culture results. 318 were from Iraq, 140 from Syria and 100 from Yemen. Median time since injury was 19 months [IQR 8-40]. Among the 732 different bacterial isolates, we identified 228 Enterobacteriaceae (31.5%), 193 Staphylococcus aureus (26.3%), 99 Pseudomonas aeruginosa (13.5%), and 21 Acinetobacter baumanii (2.8%). Three hundred and sixty four isolates were FLAR: 86.2% of Enterobacteriaceae, 53.4% of Pseudomonas aeruginosa, 60.5% of S. aureus and 45% of Acinetobacter baumannii. There was no difference in bacterial etiology or proportion of FLAR according to the country of origin. In multivariate analysis, a FLAR infection was associated with an infection of the lower extremity, with a time since the injury ≤12 months compared with time > 30 months and with more than 3 previous surgeries. CONCLUSIONS: Enterobacteriaceae were frequently involved in PTO in war wounded civilians from Iraq, Yemen and Syria between 2006 and 2016. Proportion of FLAR was high, particularly among Enterobacteriaceae, regardless of country of origin.
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Conflitos Armados , Farmacorresistência Bacteriana Múltipla , Osteomielite/epidemiologia , Ferimentos e Lesões/epidemiologia , Acinetobacter baumannii/isolamento & purificação , Adulto , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bases de Dados Factuais , Enterobacteriaceae/isolamento & purificação , Feminino , Humanos , Masculino , Oriente Médio/epidemiologia , Osteomielite/tratamento farmacológico , Osteomielite/microbiologia , Pseudomonas aeruginosa/isolamento & purificação , Estudos Retrospectivos , Staphylococcus aureus/isolamento & purificação , Ferimentos e Lesões/complicações , Ferimentos e Lesões/tratamento farmacológico , Ferimentos e Lesões/microbiologia , Adulto JovemRESUMO
BACKGROUND: Compare to high-income settings, survival in burn units in low-income settings is lower with invasive infections one leading cause of death. Médecins Sans Frontières is involved in the treatment of large burns in adults and children in Haiti. METHODS: In 2014, we performed a review of 228 patients admitted consecutively with burn injury during a 6-month period to determine patient outcomes and infectious complications. Microbiology was available through a linkage with a Haitian organization. Regression analysis was performed to determine covariates associated with bloodstream infection and mortality. RESULTS: 102 (45 %) patients were male, the median age was 8 years (IQR, 2-28), and the majority of patients (60 %) were admitted to the unit within 6 h of injury. There were 20 patients (9 %) with culture-proven bacteremia. Among organisms in blood, common isolates were Staphylococcus aureus (42 %), Pseudomonas aeruginosa (23 %), and Acinetobacter baumannii (15 %). Among patients with burns involving <40 % total body area, 4 (2 %) of 192 died and 20 (65 %) of 31 with ≥40 % body surface area involvement died. Factors associated with mortality included involvement of ≥40 % of body surface, depth, and flame as the mechanism. Multidrug-resistant infections were common; 18 % of S. aureus isolates were methicillin resistant, and 83 % of P. aeruginosa isolates were imipenem resistant. CONCLUSIONS: A low mortality rate was observed in a humanitarian burn surgery project in patients with burns involving <40 % of total body surface. Invasive infection was common and alarming rates of antibiotic resistance were observed, including infections not treatable with antibiotics available locally.
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Infecções Bacterianas/tratamento farmacológico , Queimaduras/cirurgia , Adolescente , Adulto , Antibacterianos/uso terapêutico , Bactérias/efeitos dos fármacos , Bactérias/isolamento & purificação , Queimaduras/complicações , Queimaduras/mortalidade , Criança , Pré-Escolar , Farmacorresistência Bacteriana , Feminino , Haiti , Humanos , Masculino , Estudos RetrospectivosRESUMO
Culture media is fundamental in clinical bacteriology for the detection and isolation of bacterial pathogens. However, in-house media preparation could be challenging in low-resource settings. InTray® cassettes (Biomed Diagnostics) could be a valid alternative as they are compact, ready-to-use media preparations. In this study, we evaluate the use of two InTray media as a subculture alternative for the diagnosis of bloodstream infections: the InTray® Müller-Hinton (MH) chocolate and the InTray® Colorex™ Screen. The InTray MH chocolate was evaluated in 2 steps: firstly, using simulated positive blood cultures (reference evaluation study), and secondly, using positive blood cultures from a routine clinical laboratory (clinical evaluation study). The Colorex Screen was tested using simulated poly-microbial blood cultures. The sensitivity and specificity of the InTray MH chocolate were respectively 99.2% and 90% in the reference evaluation study and 97.1% and 88.2% in the clinical evaluation study. The time to detection (TTD) was ≤20 h in most positive blood cultures (99.8% and 97% in the two studies, respectively). The InTray® MH Chocolate agar showed good performance when used directly from clinical blood cultures for single bacterial infections. However, mixed flora is more challenging to interpret on this media than on Colorex™ Screen, even for an experienced microbiologist.
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BACKGROUND: Manual blood culture bottles (BCBs) are frequently used in low-resource settings. There are few BCB performance evaluations, especially evaluations comparing them with automated systems. We evaluated two manual BCBs (Bi-State BCB and BacT/ALERT BCB) and compared their yield and time to growth detection with those of automated BacT/ALERT system. METHODS: BCBs were spiked in triplicate with 177 clinical isolates representing pathogens common in low-resource settings (19 bacterial and one yeast species) in adult and paediatric volumes, resulting in 1056 spiked BCBs per BCB system. Growth in manual BCBs was evaluated daily by visually inspecting the broth, agar slant, and, for BacT/ALERT BCB, colour change of the growth indicator. The primary outcomes were BCB yield (proportion of spiked BCB showing growth) and time to detection (proportion of positive BCB with growth detected on day 1 of incubation). 95% CI for yield and growth on day 1 were calculated using bootstrap method for clustered data using. Secondary outcomes were time to colony for all BCBs (defined as number of days between incubation and colony growth sufficient to use for further testing) and difference between time to detection in broth and on agar slant for the Bi-State BCBs. FINDINGS: Overall yield was 95·9% (95% CI 93·9-98·0) for Bi-State BCB and 95·5% (93·3-97·8) for manual BacT/ALERT, versus 96·1% (94·0-98·1) for the automated BacT/ALERT system (p=0·61). Day 1 growth was present in 920 (90·8%) of 1013 positive Bi-State BCB and 757 (75·0%) of 1009 positive manual BacT/ALERT BCB, versus 1008 (99·3%) of 1015 automated bottles. On day 2, detection rates were 100% for BI-State BCB, 97·7% for manual BacT/ALERT BCB, and 100% for automated bottles. For Bi-State BCB, growth mostly occurred simultaneously in broth and slant (81·7%). Sufficient colony growth on the slant to perform further tests was present in only 44·1% of biphasic bottles on day 2 and 59·0% on day 3. INTERPRETATION: The yield of manual BCB was comparable with the automated system, suggesting that manual blood culture systems are an acceptable alternative to automated systems in low-resource settings. Bi-State BCB outperformed manual BacT/ALERT bottles, but the agar slant did not allow earlier detection nor earlier colony growth. Time to detection for manual blood culture systems still lags that of automated systems, and research into innovative and affordable methods of growth detection in manual BCBs is encouraged. FUNDING: Médecins Sans Frontières and Department of Economy, Science and Innovation of the Flemish Government.
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Bactérias , Hemocultura , Adulto , Ágar , Criança , Humanos , LevedurasRESUMO
Use of equipment-free, "manual" blood cultures is still widespread in low-resource settings, as requirements for implementation of automated systems are often not met. Quality of manual blood culture bottles currently on the market, however, is usually unknown. An acceptable quality in terms of yield and speed of growth can be ensured by evaluating the bottles using simulated blood cultures. In these experiments, bottles from different systems are inoculated in parallel with blood and a known quantity of bacteria. Based on literature review and personal experiences, we propose a short and practical protocol for an efficient evaluation of manual blood culture bottles, aimed at research or reference laboratories in low-resource settings. Recommendations include: (1) practical equivalence of horse blood and human blood; (2) a diverse selection of 10 to 20 micro-organisms to be tested (both slow- and fast-growing reference organisms); (3) evaluation of both adult and pediatric bottle formulations and blood volumes; (4) a minimum sample size of 120 bottles per bottle type; (5) a formal assessment of usability. Different testing scenarios for increasing levels of reliability are provided, along with practical tools such as worksheets and surveys that can be used by laboratories wishing to evaluate manual blood culture bottles.
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Bactérias , Hemocultura , Animais , Criança , Meios de Cultura , Cavalos , Humanos , Reprodutibilidade dos TestesRESUMO
Easy and robust antimicrobial susceptibility testing (AST) methods are essential in clinical bacteriology laboratories (CBL) in low-resource settings (LRS). We evaluated the Beckman Coulter MicroScan lyophilized broth microdilution panel designed to support Médecins Sans Frontières (MSF) CBL activity in difficult settings, in particular with the Mini-Lab. We evaluated the custom-designed MSF MicroScan Gram-pos microplate (MICPOS1) for Staphylococcus and Enterococcus species, MSF MicroScan Gram-neg microplate (MICNEG1) for Gram-negative bacilli, and MSF MicroScan Fastidious microplate (MICFAST1) for Streptococci and Haemophilus species using 387 isolates from routine CBLs from LRS against the reference methods. Results showed that, for all selected antibiotics on the three panels, the proportion of the category agreement was above 90% and the proportion of major and very major errors was below 3%, as per ISO standards. The use of the Prompt inoculation system was found to increase the MIC and the major error rate for some antibiotics when testing Staphylococci. The readability of the manufacturer's user manual was considered challenging for low-skilled staff. The inoculations and readings of the panels were estimated as easy to use. In conclusion, the three MSF MicroScan MIC panels performed well against clinical isolates from LRS and provided a convenient, robust, and standardized AST method for use in CBL in LRS.
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BACKGROUND: War-related orthopedic injury is frequently complicated by environmental contamination and delays in management, placing victims at increased risk for long-term infectious complications. We describe, among Iraqi civilians with war-related chronic osteomyelitis, the bacteriology of infection at the time of admission. METHODS: In the Médecins Sans Frontières Reconstructive Surgery Project in Amman, Jordan, we retrospectively reviewed baseline demographics and results of initial intraoperative surgical cultures among Iraqi civilians with suspected osteomyelitis. RESULTS: One hundred thirty-seven patients (90% male; median age, 35 years [interquartile range {IQR}, 28-46]; median time since initial injury, 19 months [IQR, 10-35]) were admitted with suspected chronic osteomyelitis after war-related injury. One hundred seven patients had a positive intraoperative culture. Before arrival, patients had undergone a median of 4 (IQR, 2-6) surgical procedures in Iraq. Fifty-nine (55%) of 107 patients with confirmed osteomyelitis had a multidrug-resistant (MDR) organism isolated at admission: cefepime-resistant Enterobacteriaceae (n = 40), methicillin-resistant Staphylococcus aureus (n = 16), and MDR Acinetobacter baumannii (n = 3). An association of borderline significance existed between a history of more than two prior surgical procedures in Iraq and an MDR isolate at program entry (multivariate: odds ratio, 5.3; 95% confidence interval, 0.9-30.6; p = 0.064). CONCLUSION: Health care actors, including Iraqi health facilities and humanitarian medical organizations, must be aware of the link between chronic war injury and antimicrobial drug resistance in this region and should be prepared for the management challenges involved with the treatment of chronic drug-resistant osteomyelitis.
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Farmacorresistência Bacteriana Múltipla , Militares , Osteomielite/epidemiologia , Ferimentos e Lesões/complicações , Adulto , Doença Crônica , Feminino , Humanos , Incidência , Guerra do Iraque 2003-2011 , Masculino , Pessoa de Meia-Idade , Osteomielite/tratamento farmacológico , Osteomielite/etiologia , Estudos Retrospectivos , Estados Unidos/epidemiologia , Ferimentos e Lesões/epidemiologiaRESUMO
Bacterial identification is challenging in low-resource settings (LRS). We evaluated the MicroScan identification panels (Beckman Coulter, Brea, CA, USA) as part of Médecins Sans Frontières' Mini-lab Project. The MicroScan Dried Overnight Positive ID Type 3 (PID3) panels for Gram-positive organisms and Dried Overnight Negative ID Type 2 (NID2) panels for Gram-negative organisms were assessed with 367 clinical isolates from LRS. Robustness was studied by inoculating Gram-negative species on the Gram-positive panel and vice versa. The ease of use of the panels and readability of the instructions for use (IFU) were evaluated. Of species represented in the MicroScan database, 94.6% (185/195) of Gram-negative and 85.9% (110/128) of Gram-positive isolates were correctly identified up to species level. Of species not represented in the database (e.g., Streptococcus suis and Bacillus spp.), 53.1% out of 49 isolates were incorrectly identified as non-related bacterial species. Testing of Gram-positive isolates on Gram-negative panels and vice versa (n = 144) resulted in incorrect identifications for 38.2% of tested isolates. The readability level of the IFU was considered too high for LRS. Inoculation of the panels was favorably evaluated, whereas the visual reading of the panels was considered error-prone. In conclusion, the accuracy of the MicroScan identification panels was excellent for Gram-negative species and good for Gram-positive species. Improvements in stability, robustness, and ease of use have been identified to assure adaptation to LRS constraints.
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BACKGROUND: Culture media are fundamental in clinical microbiology. In laboratories in low- and middle-income countries (LMICs), they are mostly prepared in-house, which is challenging. OBJECTIVES: This narrative review describes challenges related to culture media in LMICs, compiles best practices for in-house media preparation, gives recommendations to improve access to quality-assured culture media products in LMICs and formulates outstanding questions for further research. SOURCES: Scientific literature was searched using PubMed and predefined MeSH terms. In addition, grey literature was screened, including manufacturer's websites and manuals as well as microbiology textbooks. CONTENT: Bacteriology laboratories in LMICs often face challenges at multiple levels: lack of clean water and uninterrupted power supply, high environmental temperatures and humidity, dust, inexperienced and poorly trained staff, and a variable supply of consumables (often of poor quality). To deal with this at a base level, one should be very careful in selecting culture media. It is recommended to look for products supported by the national reference laboratory that are being distributed by an in-country supplier. Correct storage is key, as is appropriate preparation and waste management. Centralized media acquisition has been advocated for LMICs, a role that can be taken up by the national reference laboratories, next to guidance and support of the local laboratories. In addition, there is an important role in tropicalization and customization of culture media formulations for private in vitro diagnostic manufacturers, who are often still unfamiliar with the LMIC market and the plethora of bacteriology products. IMPLICATION: The present narrative review will assist clinical microbiology laboratories in LMICs to establish best practices for handling culture media by defining quality, regulatory and research paths.
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Técnicas Bacteriológicas , Técnicas de Laboratório Clínico , Meios de Cultura , Países em Desenvolvimento , Humanos , PobrezaRESUMO
BACKGROUND: In low- and middle-income countries (LMICs), data related to antimicrobial resistance (AMR) are often inconsistently collected. Humanitarian, private and non-governmental medical organizations (NGOs), working with or in parallel to public medical systems, are sometimes present in these contexts. Yet, what is the role of NGOs in the fight against AMR, and how can they contribute to AMR data collection in contexts where reporting is scarce? How can context-adapted, high-quality clinical bacteriology be implemented in remote, challenging and underserved areas of the world? OBJECTIVES: The aim was to provide an overview of AMR data collection challenges in LMICs and describe one initiative, the Mini-Lab project developed by Médecins Sans Frontières (MSF), that attempts to partially address them. SOURCES: We conducted a literature review using PubMed and Google scholar databases to identify peer-reviewed research and grey literature from publicly available reports and websites. CONTENT: We address the necessity of and difficulties related to obtaining AMR data in LMICs, as well as the role that actors outside of public medical systems can play in the collection of this information. We then describe how the Mini-Lab can provide simplified bacteriological diagnosis and AMR surveillance in challenging settings. IMPLICATIONS: NGOs are responsible for a large amount of healthcare provision in some very low-resourced contexts. As a result, they also have a role in AMR control, including bacteriological diagnosis and the collection of AMR-related data. Actors outside the public medical system can actively contribute to implementing and adapting clinical bacteriology in LMICs and can help improve AMR surveillance and data collection.
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Técnicas Bacteriológicas , Técnicas de Laboratório Clínico , Países em Desenvolvimento , Resistência Microbiana a Medicamentos , Organizações , Coleta de Dados , HumanosRESUMO
Background: Several serological tests for SARS-CoV-2 have been developed or use, but most have only been validated on few samples, and none provide medical practitioners with an easy-to-use, self-contained, bedside test with high accuracy. Material and methods: Two-hundred fifty-six sera from 101 patients hospitalized with SARS-CoV-2 infection (positive RT-PCR) and 50 control sera were tested for IgM/IgG using the NG-Test IgM-IgG COVID all-in-one assay. The seroconversion dynamic was assessed by symptom onset and day of RT-PCR diagnosis. Results: Among the SARS-CoV-2 infected patients, positive IgG and/or IgM result was observed for 67.3% of patients (68/101), including 17 (16.8%) already positive at the day of RT-PCR, and 51 (50.5%) with observable seroconversion, and 32.7% (33/101) remained negative as subsequent sampling was not possible (patient discharge or death). The sensitivity increased with the delay between onset of symptoms and sampling, going from 29.1%, 78.2% and 86.5% for the time periods of 0-9-, 10-14- and >14-days after the onset of symptoms, respectively. Cumulative sensitivity, specificity, Positive Predictive Value and Negative Predictive Value were 97.0%, 100%, 100% and 96.2%, respectively 15-days after the onset of symptoms. No difference in seroconversion delay was observed regardless of whether patients received ventilation. Conclusions: The NG-test is a bedside serological assay that could serve as a complementary source of diagnostic information to RT-PCR and chest imaging. It may also be useful to monitor immunological status of medical and non-medical workers during the ongoing pandemic, and the general population after social distancing measures have eased.
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Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , Técnicas de Laboratório Clínico , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/imunologia , Pneumonia Viral/diagnóstico , Pneumonia Viral/imunologia , Testes Imediatos , Testes Sorológicos/métodos , Adulto , Anticorpos Antivirais/sangue , Betacoronavirus/genética , COVID-19 , Teste para COVID-19 , Estudos de Casos e Controles , Infecções por Coronavirus/virologia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/virologia , Reação em Cadeia da Polimerase , Fitas Reagentes , SARS-CoV-2 , Sensibilidade e Especificidade , Soroconversão , Testes Sorológicos/normasAssuntos
Bactérias/efeitos dos fármacos , Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana , Guerra , Infecção dos Ferimentos/microbiologia , Antibacterianos/farmacologia , Bactérias/isolamento & purificação , História do Século XXI , Humanos , Testes de Sensibilidade Microbiana , SíriaRESUMO
Bloodstream infections (BSI) have a substantial impact on morbidity and mortality worldwide. Despite scarcity of data from many low- and middle-income countries (LMICs), there is increasing awareness of the importance of BSI in these countries. For example, it is estimated that the global mortality of non-typhoidal Salmonella bloodstream infection in children under 5 already exceeds that of malaria. Reliable and accurate diagnosis of these infections is therefore of utmost importance. Blood cultures are the reference method for diagnosis of BSI. LMICs face many challenges when implementing blood cultures, due to financial, logistical, and infrastructure-related constraints. This review aims to provide an overview of the state-of-the-art of sampling and processing of blood cultures, with emphasis on its use in LMICs. Laboratory processing of blood cultures is relatively straightforward and can be done without the need for expensive and complicated equipment. Automates for incubation and growth monitoring have become the standard in high-income countries (HICs), but they are still too expensive and not sufficiently robust for imminent implementation in most LMICs. Therefore, this review focuses on "manual" methods of blood culture, not involving automated equipment. In manual blood cultures, a bottle consisting of a broth medium supporting bacterial growth is incubated in a normal incubator and inspected daily for signs of growth. The collection of blood for blood culture is a crucial step in the process, as the sensitivity of blood cultures depends on the volume sampled; furthermore, contamination of the blood culture (accidental inoculation of environmental and skin bacteria) can be avoided by appropriate antisepsis. In this review, we give recommendations regarding appropriate blood culture sampling and processing in LMICs. We present feasible methods to detect and speed up growth and discuss some challenges in implementing blood cultures in LMICs, such as the biosafety aspects, supply chain and waste management.
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Low-resource settings are disproportionately burdened by infectious diseases and antimicrobial resistance. Good quality clinical bacteriology through a well functioning reference laboratory network is necessary for effective resistance control, but low-resource settings face infrastructural, technical, and behavioural challenges in the implementation of clinical bacteriology. In this Personal View, we explore what constitutes successful implementation of clinical bacteriology in low-resource settings and describe a framework for implementation that is suitable for general referral hospitals in low-income and middle-income countries with a moderate infrastructure. Most microbiological techniques and equipment are not developed for the specific needs of such settings. Pending the arrival of a new generation diagnostics for these settings, we suggest focus on improving, adapting, and implementing conventional, culture-based techniques. Priorities in low-resource settings include harmonised, quality assured, and tropicalised equipment, consumables, and techniques, and rationalised bacterial identification and testing for antimicrobial resistance. Diagnostics should be integrated into clinical care and patient management; clinically relevant specimens must be appropriately selected and prioritised. Open-access training materials and information management tools should be developed. Also important is the need for onsite validation and field adoption of diagnostics in low-resource settings, with considerable shortening of the time between development and implementation of diagnostics. We argue that the implementation of clinical bacteriology in low-resource settings improves patient management, provides valuable surveillance for local antibiotic treatment guidelines and national policies, and supports containment of antimicrobial resistance and the prevention and control of hospital-acquired infections.
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Técnicas Bacteriológicas/normas , Bacteriologia/normas , Resistência Microbiana a Medicamentos , Recursos em Saúde/provisão & distribuição , Técnicas Bacteriológicas/métodos , Infecção Hospitalar/prevenção & controle , Países em Desenvolvimento , Humanos , Laboratórios , Garantia da Qualidade dos Cuidados de SaúdeRESUMO
Growing data suggest that antimicrobial-resistant bacterial infections are common in low- and middle-income countries. This review summarises the microbiology of key bacterial syndromes encountered in West Africa and estimates the prevalence of antimicrobial resistance (AMR) that could compromise first-line empirical treatment. We systematically searched for studies reporting on the epidemiology of bacterial infection and prevalence of AMR in West Africa within key clinical syndromes. Within each syndrome, the pooled proportion and 95% confidence interval were calculated for each pathogen-antibiotic pair using random-effects models. Among 281 full-text articles reviewed, 120 met the eligibility criteria. The majority of studies originated from Nigeria (70; 58.3%), Ghana (15; 12.5%) and Senegal (15; 12.5%). Overall, 43 studies (35.8%) focused on urinary tract infections (UTI), 38 (31.7%) on bloodstream infections (BSI), 27 (22.5%) on meningitis, 7 (5.8%) on diarrhoea and 5 (4.2%) on pneumonia. Children comprised the majority of subjects. Studies of UTI reported moderate to high rates of AMR to commonly used antibiotics including evidence of the emergence of cephalosporin resistance. We found moderate rates of AMR among common bloodstream pathogens to typical first-line antibiotics including ampicillin, cotrimoxazole, gentamicin and amoxicillin/clavulanate. Among S. pneumoniae strains isolated in patients with meningitis, levels of penicillin resistance were low to moderate with no significant resistance noted to ceftriaxone or cefotaxime. AMR was common in this region, particularly in hospitalized patients with BSI and both outpatient and hospitalized patients with UTI. This raises concern given the limited diagnostic capability and second-line treatment options in the public sector in West Africa.
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Infecções Bacterianas/epidemiologia , Infecções Bacterianas/microbiologia , Farmacorresistência Bacteriana , África Ocidental/epidemiologia , Humanos , PrevalênciaRESUMO
OBJECTIVE: In low- and middle-income countries, bloodstream infections are an important cause of mortality in patients with burns. Increasingly implicated in burn-associated infections are highly drug-resistant pathogens with limited treatment options. We describe the epidemiology of bloodstream infections in patients with burns in a humanitarian surgery project in Iraq. METHODS: We performed a retrospective, descriptive study of blood culture isolates identified between July 2008 and September 2009 among patients with burns in a single hospital in Iraq who developed sepsis. RESULTS: In 1169 inpatients admitted to the burn unit during the study period, 212 (18%) had suspected sepsis, and 65 (6%) had confirmed bacteremia. Sepsis was considered the primary cause of death in 198 patients (65%; 95% CI 65-70) of the 304 patients that died. The most commonly isolated organisms were Pseudomonas aeruginosa (22 isolates [34%]), Staphylococcus aureus (17 [26%]), Klebsiella pneumoniae (8 [12%]), Staphylococcus epidermidis (7 [11%]), Acinetobacter baumannii (6 [9%]), and Enterobacter cloacae (5 [8%]). A high proportion of Enterobacteriaceae strains produced extended-spectrum beta-lactamase and S. aureus isolates were uniformly methicillin-resistant. For gram-negative bacteria, the most reliably active antibiotics were imipenen and amikacin. CONCLUSIONS: Burn patients with sepsis in Iraq were commonly found to have bloodstream pathogens resistant to most antibiotics available locally. Effective empirical therapy of burn sepsis in this region of Iraq would consist of vancomycin or teicoplanin and a carbapenem-class antibiotic with antipseudomonal activity.