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Yacouba A, Bellali S, Haddad G, Mavros N, Fontanini A, Dubourg G, Lagier JC, Raoult D, Bou Khalil J. Use of scanning electron microscopy and energy dispersive X-ray for urine analysis: A preliminary investigation. Microsc Res Tech 2023; 86:1249-1257. [PMID: 36773029 DOI: 10.1002/jemt.24301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/21/2023] [Accepted: 01/30/2023] [Indexed: 02/12/2023]
Abstract
Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) are powerful tools to study the ultrastructure of numerous specimens and to determine their elemental composition, respectively. However, results have not yet been reported on their application to urine samples in routine clinical laboratory practice. Herein we investigate urine sediment by using SEM and EDX to detect and identify different urine components. A total of 206 urine samples from patients with and without urinary tract infections were analyzed using SEM and EDX. Microorganisms, crystals, epithelial cells, leukocytes, and erythrocytes were targeted in urine sediment samples. The identification of urine components was based on their morphology, size, contrast, and elemental composition. SEM-analysis allowed us to identify and classify microorganisms in urine sediments into the categories of gram-negative bacilli, cluster cocci, chain cocci, gram-negative bacilli, gram-positive bacilli, and yeasts. In addition, various types of epithelial cells such as renal, transitional, and squamous epithelial cells were found. Furthermore, leukocytes and erythrocytes were well identified, with the detection of various morphological forms of erythrocytes, such as dysmorphic and isomorphic erythrocytes. Using SEM-EDX analysis, calcium oxalate was the most frequently-identified crystal (92.0%), with prominent peaks of C, O, and Ca elements, followed by struvite (6%), with peaks of Mg, P, O, and N. These preliminary data suggest that the two complementary SEM-EDX analyses can be used to detect and identify microorganisms and crystals in urine samples. Further studies are still needed to apply SEM-EDX to urine sediment analysis. SEM-EDX analyses provided comparative results with the routine results, with accurate identification, high resolution and deep focus compared to the routine urinalysis SEM-analysis allowed us to identify and classify microorganisms in urine sediments into the categories of gram-negative bacilli, cluster cocci, chain cocci, gram-negative bacilli, gram-positive bacilli and yeasts. SEM-EDX analysis enabled the accurate identification of crystals based on both morphology and elemental composition.
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Affiliation(s)
- Abdourahamane Yacouba
- IRD, AP-HM, MEPHI, Aix Marseille University, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
- Université Abdou Moumouni, Niamey, Niger
| | | | - Gabriel Haddad
- IRD, AP-HM, MEPHI, Aix Marseille University, Marseille, France
- IHU-Méditerranée Infection, Marseille, France
| | | | | | - Grégory Dubourg
- IRD, AP-HM, MEPHI, Aix Marseille University, Marseille, France
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Zmerli O, Bellali S, Haddad G, Hisada A, Ominami Y, Raoult D, Bou Khalil J. Rapid microbial viability assay using scanning electron microscopy: a proof-of-concept using Phosphotungstic acid staining. Comput Struct Biotechnol J 2023; 21:3627-3638. [PMID: 37501704 PMCID: PMC10371768 DOI: 10.1016/j.csbj.2023.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 06/27/2023] [Accepted: 07/09/2023] [Indexed: 07/29/2023] Open
Abstract
Multiple stains have been historically utilized in electron microscopy to provide proper contrast and superior image quality enabling the discovery of ultrastructures. However, the use of these stains in microbiological viability assessment has been limited. Phosphotungstic acid (PTA) staining is a common negative stain used in scanning electron microscopy (SEM). Here, we investigate the feasibility of a new SEM-PTA assay, aiming to determine both viable and dead microbes. The optimal sample preparation was established by staining bacteria with different PTA concentrations and incubation times. Once the assay conditions were set, we applied the protocol to various samples, evaluating bacterial viability under different conditions, and comparing SEM-PTA results to culture. The five minutes 10% PTA staining exhibited a strong distinction between viable micro-organisms perceived as hypo-dense, and dead micro-organisms displaying intense internal staining which was confirmed by high Tungsten (W) peak on the EDX spectra. SEM-PTA viability count after freezing, freeze-drying, or oxygen exposure, were concordant with culture. To our knowledge, this study is the first contribution towards PTA staining of live and dead bacteria. The SEM-PTA strategy demonstrated the feasibility of a rapid, cost-effective and efficient viability assay, presenting an open-view of the sample, and providing a potentially valuable tool for applications in microbiome investigations and antimicrobial susceptibility testing.
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Affiliation(s)
- Omar Zmerli
- Institut Hospitalo-Universitaire Méditerranée Infection 19-21 Boulevard Jean Moulin 13005 Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
| | - Sara Bellali
- Institut Hospitalo-Universitaire Méditerranée Infection 19-21 Boulevard Jean Moulin 13005 Marseille, France
| | - Gabriel Haddad
- Institut Hospitalo-Universitaire Méditerranée Infection 19-21 Boulevard Jean Moulin 13005 Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
| | - Akiko Hisada
- Hitachi, Ltd. Research & Development Group, 2520, Akanuma, Hatoyama, Saitama, 350- 0395, Japan
| | - Yusuke Ominami
- Hitachi High-Tech Corporation, 882 Ichige, Hitachinaka-shi, Ibaraki-ken 312-8504, Japan
| | | | - Jacques Bou Khalil
- Institut Hospitalo-Universitaire Méditerranée Infection 19-21 Boulevard Jean Moulin 13005 Marseille, France
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), UMR Microbes Evolution Phylogeny and Infections (MEPHI), Marseille, France
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3
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Weng TP, Lo CL, Lin WL, Lee JC, Li MC, Ko WC, Lee NY. Integration of antimicrobial stewardship intervention with rapid organism identification improve outcomes in adult patients with bloodstream infections. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2023; 56:57-63. [PMID: 35922267 DOI: 10.1016/j.jmii.2022.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 06/23/2022] [Accepted: 07/07/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Integration of antimicrobial stewardship intervention (ASI) with rapid organism identification has the potential for early customization of antimicrobial therapy and improved clinical outcomes. We aimed to evaluate the impact of this combined approach on antimicrobial therapy-related outcomes in patients with bloodstream infections (BSIs). MATERIALS AND METHODS A pre-post quasi-experimental study was conducted to analyze the impact of ASI with organism identification via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) among patients with BSIs. Outcomes were compared to a historic pre-intervention group. The 30-day mortality was the primary endpoint. Secondary outcomes included time to first antibiotic modification, length of hospital stay. RESULTS A total of 1004 adult patients with BSIs were included in the final analysis, 519 patients classified into the intervention group and 485 patients in the preintervention group. The patients in the intervention group were younger (66 vs. 70 years, P = 0.02). The 30-day crude mortality (14.6% vs. 29.9%, P < 0.001) was lower, the time to organism identification (72.25 vs. 83.6 h, P < 0.001) and length of hospital stay (12 days vs. 14 days, P < 0.001) were shorter in the intervention group. Acceptance of an ASI was associated with a trend toward a reduced 30-day mortality on multivariable analysis (odds ratio 0.33; 95% CI: 0.24-0.47; P < 0.001). CONCLUSION The ASI combined with MALDI-TOF-MS approach decreased time to organism identification and time to appropriate antimicrobial therapy would achieve a better clinical outcome in the patients with BSIs.
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Affiliation(s)
- Tzu-Ping Weng
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ching-Lung Lo
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Liang Lin
- Department of Pharmacy, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jen-Chieh Lee
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Ming-Chi Li
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Nan-Yao Lee
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
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Javelle E, Carvelli J, Delandre O, Gendrot M, Fonta I, Mosnier J, Benoît N, Madamet M, L'Ollivier C, Pradines B. Unusual blood smear with multiple stages of plasmodium falciparum infection and intraleukocytic malaria pigments in an expatriate with severe malaria and delayed clearance of parasites. J Travel Med 2023; 30:7001841. [PMID: 36694975 DOI: 10.1093/jtm/taad012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 01/24/2023] [Accepted: 01/17/2023] [Indexed: 01/26/2023]
Abstract
A French expatriate in Ethiopia presented with severe Plasmodium falciparum infection. The blood smear was remarkable associating multiple stages of parasites including circulating schizonts with a high rate of intraleukocytic malaria pigments. Under artesunate treatment, without polymorphism in PfK13 gene, delayed clearance of parasites occurred, probably following the massive merogony.
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Affiliation(s)
- Emilie Javelle
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Julien Carvelli
- AP-HM, Department of Intensive Care, Réanimation des Urgences, Medicine Intensive & Reanimation, Timone University Hospital, Marseille, France.,Marseille Immunopôle, Timone University Hospital, CNRS, INSERM, CIML, Marseille, France.,Aix-Marseille University, Marseille, France
| | - Océane Delandre
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Mathieu Gendrot
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Isabelle Fonta
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Joel Mosnier
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Nicolas Benoît
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Marilyn Madamet
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
| | - Coralie L'Ollivier
- Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France
| | - Bruno Pradines
- Unité Parasitologie et Entomologie, Département Microbiologie et Maladies Infectieuses, Institut de Recherche Biomédicale des Armées (IRBA), Marseille, France.,Aix Marseille Univ, IRD, SSA, AP-HM, VITROME, Marseille, France.,IHU Méditerranée Infection, Marseille, France.,Centre National de Référence du Paludisme, Marseille, France
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5
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Haddad G, Takakura T, Bellali S, Fontanini A, Ominami Y, Khalil JB, Raoult D. A preliminary investigation into bacterial viability using scanning electron microscopy–energy-dispersive X-ray analysis: The case of antibiotics. Front Microbiol 2022; 13:967904. [PMID: 36003945 PMCID: PMC9393632 DOI: 10.3389/fmicb.2022.967904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
The metabolic stages of bacterial development and viability under different stress conditions induced by disinfection, chemical treatments, temperature, or atmospheric changes have been thoroughly investigated. Here, we aim to evaluate early metabolic modifications in bacteria following induced stress, resulting in alterations to bacterial metabolism. A protocol was optimized for bacterial preparation using energy-dispersive X-ray (EDX) microanalysis coupled with scanning electron microscopy (SEM), followed by optimizing EDX data acquisition and analysis. We investigated different preparation methods aiming to detect modifications in the bacterial chemical composition at different states. We first investigated Escherichia coli, acquiring data from fresh bacteria, after heat shock, and after contact with 70% ethanol, in order to prove the feasibility of this new strategy. We then applied the new method to different bacterial species following 1 h of incubation with increasing doses of antibiotics used as a stress-inducing agent. Among the different materials tested aiming to avoiding interaction with bacterial metabolites, phosphorous-doped silicon wafers were selected for the slide preparation. The 15 kV acceleration voltage ensured all the chemical elements of interest were excited. A thick layer of bacterial culture was deposited on the silicon wafer providing information from multiple cells and intra-cellular composition. The EDX spectra of fresh, heat-killed, and alcohol-killed E. coli revealed important modifications in magnesium, potassium, and sodium. Those same alterations were detected when applying this strategy to bacteria exposed to antibiotics. Tests based on SEM–EDX acquisition systems would provide early predictions of the bacterial viability state in different conditions, yielding earlier results than culture.
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Affiliation(s)
- Gabriel Haddad
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Aix-Marseille Univ, IRD, APHM, MEPHI, Marseille, France
| | | | - Sara Bellali
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | - Anthony Fontanini
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
| | | | - Jacques Bou Khalil
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Jacques Bou Khalil,
| | - Didier Raoult
- Institut Hospitalo-Universitaire Méditerranée Infection, Marseille, France
- Aix-Marseille Univ, IRD, APHM, MEPHI, Marseille, France
- *Correspondence: Didier Raoult,
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6
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Petit C, Lavrard-Meyer P, Raoult D, Dubourg G. The absolute number of leukocytes per vial as a major cause of early false positive blood cultures: proof-of-concept and application. Eur J Clin Microbiol Infect Dis 2022; 41:951-959. [PMID: 35583717 DOI: 10.1007/s10096-022-04454-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/03/2022] [Indexed: 11/24/2022]
Abstract
Blood cultures detected as positive by the automated system but negative by microscopy and subculture are considered as "false-positives." Several causes have been identified, including hyperleukocytosis or the presence of fastidious bacteria, but as many cases remain unexplained we aimed to investigate the false positives occurring in our laboratory. We retrospectively collected data on blood cultures received over a period of 12 months to determine factors associated with the false-positive vials. We then prospectively validated our findings on the false-positive results occurring over a 3.5-month period. We finally applied scanning electron microscopy (SEM) on 63 false positives and molecular approaches on a subset of them. In the retrospective study, 154 (85%) of the 181 false-positive identified were positive following less than 4 h of incubation and were considered as "early false-positives." By performing ROC curves on these early false positives, we demonstrate that the absolute number of leukocytes is in fact the most discriminating factor of early false positivity (p < 0.001). This phenomenon can be the consequence of either a high blood culture volume (p < 0.001) or hyperleukocytosis (p < 0.001). In the prospective study, the use of a threshold of 219 million of leukocytes per vial enabled the identification of 97% of the early false positives. Finally, SEM and specific qPCR enabled three additional identifications while 16S rRNA/nanopore sequencing enabled the detection of Helicobacter cinaedi bacteremia and a polymicrobial infection. A high absolute number of leukocytes in blood cultures explains most false positives, thereby making it possible to target additional microbiological investigations.
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Affiliation(s)
- Camille Petit
- Aix-Marseille Université, IRD, AP‑HM, MEPHI, IHU-Méditerranée Infection, 19‑21 Boulevard Jean Moulin, Cedex 5, 13385, Marseille, France
| | - Philippe Lavrard-Meyer
- Aix-Marseille Université, IRD, AP‑HM, MEPHI, IHU-Méditerranée Infection, 19‑21 Boulevard Jean Moulin, Cedex 5, 13385, Marseille, France
| | - Didier Raoult
- Aix-Marseille Université, IRD, AP‑HM, MEPHI, IHU-Méditerranée Infection, 19‑21 Boulevard Jean Moulin, Cedex 5, 13385, Marseille, France
| | - Grégory Dubourg
- Aix-Marseille Université, IRD, AP‑HM, MEPHI, IHU-Méditerranée Infection, 19‑21 Boulevard Jean Moulin, Cedex 5, 13385, Marseille, France.
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7
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Zhang W, Chen X, Zhang J, Chen X, Zhou L, Wang P, Hong W. Rapid antimicrobial susceptibility testing for mixed bacterial infection in urine by AI-stimulated Raman scattering metabolic imaging. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2022. [DOI: 10.1016/j.medntd.2022.100132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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8
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Doublier M, Raoult D, Dubourg G. An unusual Gram-positive spiral-shaped bacilli detected in a positive blood culture. Clin Microbiol Infect 2022; 28:1449-1450. [PMID: 35026377 PMCID: PMC8747776 DOI: 10.1016/j.cmi.2022.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 12/08/2021] [Accepted: 01/02/2022] [Indexed: 11/26/2022]
Affiliation(s)
- Maxime Doublier
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (AP-HM), MEPHI, 27 Boulevard Jean Moulin, 13005 Marseille, France; IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
| | - Didier Raoult
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (AP-HM), MEPHI, 27 Boulevard Jean Moulin, 13005 Marseille, France; IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
| | - Grégory Dubourg
- Aix-Marseille Université, Institut de Recherche pour le Développement (IRD), Assistance Publique-Hôpitaux de Marseille (AP-HM), MEPHI, 27 Boulevard Jean Moulin, 13005 Marseille, France; IHU Méditerranée Infection, 19-21 Boulevard Jean Moulin, 13005 Marseille, France.
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9
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Bellali S, Haddad G, Iwaza R, Fontanini A, Hisada A, Ominami Y, Raoult D, Khalil JB. Antimicrobial susceptibility testing for Gram positive cocci towards vancomycin using scanning electron microscopy. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100154. [PMID: 35909629 PMCID: PMC9325908 DOI: 10.1016/j.crmicr.2022.100154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
SEM-based method can be applied for rapid phenotypic AST on Gram-positive cocci towards 2 vancomycin based on morphological changes 3. The ratio of septa as a marker of bacterial division and size of grape-like clusters enabled the 4 profiling of E. faecalis, E. faecium and S. aureus after brief incubation with vancomycin 5. SEM-AST strategy showed the feasibility of detecting antibiotic susceptibility or 6 resistance on Gram-positive cocci within one hour of exposition to vancomycin 7.
The rapid detection of resistant bacteria has become a challenge for microbiologists worldwide. Numerous pathogens that cause nosocomial infections are still being treated empirically and have developed resistance mechanisms against key antibiotics. Thus, one of the challenges for researchers has been to develop rapid antimicrobial susceptibility testing (AST) to detect resistant isolates, ensuring better antibiotic stewardship. In this study, we established a proof-of-concept for a new strategy of phenotypic AST on Gram-positive cocci towards vancomycin using scanning electron microscopy (SEM). Our study evaluated the profiling of Enterococcus faecalis, Enterococcus faecium and Staphylococcus aureus after brief incubation with vancomycin. Sixteen isolates were analysed aiming to detect ultrastructural modifications at set timepoints, comparing bacteria with and without vancomycin. After optimising slides preparation and micrographs acquisition, two analytical strategies were used. The high magnification micrographs served to analyse the division of cocci based on the ratio of septa, along with the bacterial size. Susceptible strains with vancomycin showed a reduced septa percentage and the average surface area was consequently double that of the controls. The resistant bacteria revealed multiple septa occurring at advanced timepoints. Low magnification micrographs made it possible to quantify the pixels at different timepoints, confirming the profiling of cocci towards vancomycin. This new phenotypic AST strategy proved to be a promising tool to discriminate between resistant and susceptible cocci within an hour of contact with vancomycin. The analysis strategies applied here would potentially allow the creation of artificial intelligence algorithms for septa detection and bacterial quantification, subsequently creating a rapid automated SEM-AST assay.
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10
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Su X, Guo Y, Fang T, Jiang X, Wang D, Li D, Bai P, Zhang B, Wang J, Liu C. Effects of Simulated Microgravity on the Physiology of Stenotrophomonas maltophilia and Multiomic Analysis. Front Microbiol 2021; 12:701265. [PMID: 34512577 PMCID: PMC8429793 DOI: 10.3389/fmicb.2021.701265] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/29/2021] [Indexed: 11/13/2022] Open
Abstract
Many studies have shown that the space environment plays a pivotal role in changing the characteristics of conditional pathogens, especially their pathogenicity and virulence. However, Stenotrophomonas maltophilia, a type of conditional pathogen that has shown to a gradual increase in clinical morbidity in recent years, has rarely been reported for its impact in space. In this study, S. maltophilia was exposed to a simulated microgravity (SMG) environment in high-aspect ratio rotating-wall vessel bioreactors for 14days, while the control group was exposed to the same bioreactors in a normal gravity (NG) environment. Then, combined phenotypic, genomic, transcriptomic, and proteomic analyses were conducted to compare the influence of the SMG and NG on S. maltophilia. The results showed that S. maltophilia in simulated microgravity displayed an increased growth rate, enhanced biofilm formation ability, increased swimming motility, and metabolic alterations compared with those of S. maltophilia in normal gravity and the original strain of S. maltophilia. Clusters of Orthologous Groups (COG) annotation analysis indicated that the increased growth rate might be related to the upregulation of differentially expressed genes (DEGs) involved in energy metabolism and conversion, secondary metabolite biosynthesis, transport and catabolism, intracellular trafficking, secretion, and vesicular transport. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed that the increased motility might be associated the upregulation of differentially expressed proteins (DEPs) involved in locomotion, localization, biological adhesion, and binding, in accordance with the upregulated DEGs in cell motility according to COG classification, including pilP, pilM, flgE, flgG, and ronN. Additionally, the increased biofilm formation ability might be associated with the upregulation of DEPs involved in biofilm formation, the bacterial secretion system, biological adhesion, and cell adhesion, which were shown to be regulated by the differentially expressed genes (chpB, chpC, rpoN, pilA, pilG, pilH, and pilJ) through the integration of transcriptomic and proteomic analyses. These results suggested that simulated microgravity might increase the level of corresponding functional proteins by upregulating related genes to alter physiological characteristics and modulate growth rate, motility, biofilm formation, and metabolism. In conclusion, this study is the first general analysis of the phenotypic, genomic, transcriptomic, and proteomic changes in S. maltophilia under simulated microgravity and provides some suggestions for future studies of space microbiology.
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Affiliation(s)
- Xiaolei Su
- Medical School of Chinese PLA, Beijing, China.,Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Yinghua Guo
- Medical School of Chinese PLA, Beijing, China.,College of Pulmonary and Critical Care Medicine, The Eighth Medical Center, Chinese PLA General Hospital, Beijing, China
| | - Tingzheng Fang
- Medical School of Chinese PLA, Beijing, China.,Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Xuege Jiang
- Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Dapeng Wang
- Medical School of Chinese PLA, Beijing, China.,Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Diangeng Li
- Department of Academic Research, Beijing Chaoyang Hospital Affiliated to Capital Medical University, Beijing, China
| | - Po Bai
- Respiratory Diseases Department, PLA Rocket Force Characteristic Medical Center, Beijing, China
| | - Bin Zhang
- Department of Respiratory and Critical Care Medicine, Binzhou Medical University Hospital, Binzhou, China
| | - Junfeng Wang
- Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
| | - Changting Liu
- Department of Respiratory and Critical Care Medicine, The Second Medical Center and National Clinical Research Center for Geriatric Disease, Chinese PLA General Hospital, Beijing, China
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