Omar Zmerli

Dr. Omar Zmerli

MEPHI, Aix-Marseille University, Marseille, Provence-Alpes-Côte d’Azur, France
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Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 December 2020 in Journal of Infection and Public Health
Verified
Journal Article
Open access
ACAmanda Chamieh
Amanda Chamieh
Gerard El HajjGerard El Hajj
Gerard El Hajj
OZOmar Zmerli
Omar Zmerli
CAClaude Afif
Claude Afif
EAEid Azar
Eid Azar
Carbapenem resistant organisms (CRO) constitute a large group of bacteria with different mechanisms of resistance and recently increasing global incidence. This rise has ambiguous dynamics and essential local epidemiologic data is lacking. In this retrospective study at the 400-bed Saint George Hospital (SGH) in Beirut, Lebanon, we retrieved electronic laboratory records of all intrinsic and acquired CRO isolates from January 1, 2010 until June 30, 2018. Isolation density was calculated as: number of isolates/1000PD. Analysis carried out using WHOnet with a trend time series analysis. During the study period, a total of 2150 non-duplicate CRO were isolated. While Acinetobacter baumanii (AB), Pseudomonas aeruginosa (CRPa), and Stenotrophomonas maltophilia (Sm) constituted 85% of total CRO in the study period, the carbapenem resistant enterobacteriaceae (CRE) rose from few sporadic cases before 2016 to a solid 32% of total CRO in 2018. Our most concrete trends were as follows. The rate of AB bacteremia was at an average of 0.114/1000 PD from 2011 to 2014. In 2015, a sudden doubling of AB bacteremia to 0.23/1000 PD. In 2017, there was a significant decrease to 0.113/1,000PD (p < 0.0001) to reach 0.097/1000PD in 2018 with a continuously declining trend. The peak of Sm bacteremia was in 2016 at 0.121/1000PD after which it significantly decreased by 21% in 2017 to disappear in 2018 (p < 0.0001). There were no significant trends observed in the isolation density of the CRPa group from 2010 until June 2018. Klebsiella pneumonia (CRKp) bacteremia was isolated first in 2013, then in 2016 and continued to rise (p = 0.028). In 2017, carbapenem resistant KP bacteremia rate doubled to 0.05/1,000PD from 0.024/1000 (p = 0.0139). In conclusion, this 9-year study at SGH depicts the major trends and dynamics of local CRO isolation, mainly A. baumanii, P. aeruginosa and CRKp. Further efforts are warranted both locally and internationally for a richer understanding of this trend. Bearing in mind that understanding antimicrobial resistance is a complex, multifaceted process that is only feasible when all its aspects are combined: molecular, phenotypic and clinical.

21 August 2021 in Antibiotics
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Journal Article
Open access
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ACAmanda Chamieh
Amanda Chamieh
RZRita Zgheib
Rita Zgheib
SESabah El-Sawalhi
Sabah El-Sawalhi
LYLaure Yammine
Laure Yammine
Gerard El HajjGerard El Hajj
Gerard El Hajj
EAEid Azar
Eid Azar
Introduction: We studied the trend of antimicrobial resistance and consumption at Saint George Hospital University Medical Center (SGHUMC), a tertiary care center in Beirut, Lebanon, with a focus on the SARS-CoV-2 pandemic. Materials and Methods: We calculated the isolation density/1000 patient-days (PD) of the most isolated organisms from 1 January 2015–31 December 2020 that included: E. coli (Eco), K. pneumoniae (Kp), P. aeruginosa (Pae), A. baumannii (Ab), S. aureus (Sau), and E. faecium (Efm). We considered March–December 2020 a surrogate of COVID-19. We considered one culture/patient for each antimicrobial susceptibility and excluded Staphylococcus epidermidis, Staphylococcus coagulase-negative, and Corynebacterium species. We analyzed the trends of the overall isolates, the antimicrobial susceptibilities of blood isolates (BSI), difficult-to-treat (DTR) BSI, carbapenem-resistant Enterobacteriaceae (CRE) BSI, and restricted antimicrobial consumption as daily-defined-dose/1000 PD. DTR implies resistance to carbapenems, beta-lactams, fluoroquinolones, and additional antimicrobials where applicable. Results and Discussion: After applying exclusion criteria, we analyzed 1614 blood cultures out of 8314 cultures. We isolated 85 species, most commonly Eco, at 52%. The isolation density of total BSI in 2020 decreased by 16%: 82 patients were spared from bacteremia, with 13 being DTR. The isolation density of CRE BSI/1000 PD decreased by 64% from 2019 to 2020, while VREfm BSI decreased by 34%. There was a significant decrease of 80% in Ab isolates (p-value < 0.0001). During COVID-19, restricted antimicrobial consumption decreased to 175 DDD/1000 PD (p-value < 0.0001). Total carbapenem consumption persistently decreased by 71.2% from 108DDD/1000 PD in 2015–2019 to 31 DDD/1000 PD in 2020. At SGHUMC, existing epidemics were not worsened by the pandemic. We attribute this to our unique and dynamic collaboration of antimicrobial stewardship, infection prevention and control, and infectious disease consultation.

9 June 2025 in Gut Microbes
Verified
Journal Article
Open access
MBMeriem Boukili
Meriem Boukili
OZOmar Zmerli
Omar Zmerli
FFFlorence Fenollar
Florence Fenollar
SBSara Bellali
Sara Bellali
JKJacques Bou Khalil
Jacques Bou Khalil
The Gut Microbiota (GM) remains a complex microbial ecosystem with many unknown facets despite significant technologic advancement. This study introduces a novel rapid technique using tabletop scanning electron microscopy (SEM) for investigating GM composition, focusing on Clostridioides difficile infection (CDI) as a representative model for dysbiosis-related diseases. Six stool sample preparation protocols were tested on 40 stool samples to develop an optimized SEM protocol. Protocol stability was evaluated after four-month storage. The optimized protocol produced high-resolution micrographs while maintaining sample integrity over time. SEM investigation of GM was done by analyzing ten stool samples (5-control and 5-C. difficile groups), imaged at low and high magnifications. Object detection analysis generated a SEM-based GM components database helping describe and compare microbial diversity variation between the groups. CDI group revealed a reduction in microbial diversity, compared to the controls. Epithelial and red blood cells were more prevalent in CDI group. Statistical analyses of objects proved clear clustering of samples into CDI and control groups. This study pioneers the proof-of-concept for using tabletop SEM to investigate GM components in a dysbiosis-related disease model. This concept emerges as a complementary technique capable of providing deeper insight to describe GM components previously elusive with other methods.

1 January 2024 in International Journal of Microbiology
Verified
Journal Article
Open access
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OZOmar Zmerli
Omar Zmerli
SBSara Bellali
Sara Bellali
GHGabriel Haddad
Gabriel Haddad
RIRim Iwaza
Rim Iwaza
AHAkiko Hisada
Akiko Hisada
JKJacques Bou Khalil
Jacques Bou Khalil
Background. Colistin (Polymyxin E) has reemerged in the treatment of MDR Gram‐negative infections. Traditional Colistin AST methods have long turnaround times and are cumbersome for routine use. We present a SEM‐AST technique enabling rapid detection of Colistin resistance through direct observation of morphological and quantitative changes in bacteria exposed to Colistin. Methods. Forty‐four Gram‐negative reference organisms were chosen based on their Colistin susceptibility profiles. Bacterial suspensions of ∼107 CFU/mL were exposed to Colistin at EUCAST‐ECOFF, with controls not exposed, incubated at 37°C, and then sampled at 0, 15, 30, 60, and 120 minutes. Phosphotungstic Acid (PTA) staining was applied, followed by SEM imaging using Hitachi TM4000PlusII‐Tabletop‐SEM at ×2000, ×5000 and ×7000 magnifications. Bacterial viability analysis was performed for all conditions by quantifying viable and dead organisms based on PTA‐staining and morphologic changes. Results. We identified a significant drop in the percentage of viable organisms starting 30 minutes after exposure in susceptible strains, as compared to nonsignificant changes in resistant strains across all tested organisms. The killing effect of Colistin was best observed after 120 minutes of incubation with the antibiotic, with significant changes in morphologic features, including bacterial inflation, fusion, and lysis, observed as early as 30 minutes. Our observation matched the results of the gold standard‐based broth microdilution method. Conclusions. We provide an extended application of the proof of concept for the utilization of the SEM‐AST assay for Colistin for a number of clinically relevant bacterial species, providing a rapid and reliable susceptibility profile for a critical antibiotic.

19 October 2022 in PLOS ONE
Verified
Journal Article
Open access
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MNMoni Nader
Moni Nader
OZOmar Zmerli
Omar Zmerli
DPDaniel E. Platt
Daniel E. Platt
HHHamdan Hamdan
Hamdan Hamdan
SHSalwa Hamdash
Salwa Hamdash
EAEid Azar
Eid Azar
The COVID-19 pandemic claimed millions of lives worldwide without clear signs of abating despite several mitigation efforts and vaccination campaigns. There have been tremendous interests in understanding the etiology of the disease particularly in what makes it severe and fatal in certain patients. Studies have shown that COVID-19 patients with kidney injury on admission were more likely to develop severe disease, and acute kidney disease was associated with high mortality in COVID-19 hospitalized patients. This study investigated 819 COVID-19 patients admitted between January 2020-April 2021 to the COVID-19 ward at a tertiary care center in Lebanon and evaluated their vital signs and biomarkers while probing for two main outcomes: intubation and fatality. Logistic and Cox regressions were performed to investigate the association between clinical and metabolic variables and disease outcomes, mainly intubation and mortality. Times were defined in terms of admission and discharge/fatality for COVID-19, with no other exclusions. Regression analysis revealed that the following are independent risk factors for both intubation and fatality respectively: diabetes (p = 0.021 and p = 0.04), being overweight (p = 0.021 and p = 0.072), chronic kidney disease (p = 0.045 and p = 0.001), and gender (p = 0.016 and p = 0.114). Further, shortness of breath (p<0.001), age (p<0.001) and being overweight (p = 0.014) associated with intubation, while fatality with shortness of breath (p<0.001) in our group of patients. Elevated level of serum creatinine was the highest factor associated with fatality (p = 0.002), while both white blood count (p<0.001) and serum glutamic-oxaloacetic transaminase levels (p<0.001) emerged as independent risk factors for intubation. Collectively our data show that high creatinine levels were significantly associated with fatality in our COVID-19 study patients, underscoring the importance of kidney function as a main modulator of SARS-CoV-2 morbidity and favor a careful and proactive management of patients with elevated creatinine levels on admission.

30 November 2020 in medRxiv
Verified
Preprint
Open access
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ACAmanda Chamieh
Amanda Chamieh
RWRania Warrak
Rania Warrak
LTLucie Tawk
Lucie Tawk
OZOmar Zmerli
Omar Zmerli
CAClaude Afif
Claude Afif
EAEid Azar
Eid Azar
There is growing evidence of cluster transmission and superspreading of SARS-CoV-2, implying heterogeneous dispersion. We discuss the successful containment of COVID-19 local outbreak in Bcharreh, the small town of 4500 inhabitants, in Northern Lebanon. We look at the dynamics of cluster transmission and viral load evolution throughout the outbreak. SARS-CoV-2 PCR test was proposed to all exposed individuals. Persons under investigation that tested negative by PCR were periodically retested. We define: a cluster as more than 3 people with a common suspicious or confirmed SARS-CoV-2 positive contact, clinical cure as the resolution of symptoms, and virologic cure as SARS-CoV-2 PCR Cycle threshold(Ct) >35. We analyzed all obtained Ct into corresponding clusters and performed a time series analysis. A total of 713/871 SARS-CoV-2 PCR tests were performed at Saint George Hospital University Medical Center (SGHUMC) from April 5 th 2020 -June 14 th 2020. We used the LightMix® Modular SARS-CoV-2 (COVID19) E, N, and RdRP-genes (Tib Molbiol, Berlin, Germany). Week one of epidemiologic surveillance began on March 31 st when the first case was detected. A strict lockdown was imposed on Bcharreh village 5 days later, on top of the national lockdown. We identified 4 different clusters ranging from 3 to 27 cases and 3 sporadic unrelated cases. Almost 70% of each cluster was diagnosed within 7 days. After 2 weeks, we saw a significant increase in the average initial diagnostic Ct 27.9 to 34.72 (P<0.0001). A total of 73/74 SARS-CoV-2 PCR positive individuals achieved cure (98.6%). We recorded one death of a 90-year-old man with multiple comorbidities. In explosive new epidemics, we can derive from previous experience and not be blinded by it. To safely navigate out of the lockdown, focus on where new transmission is likely to emerge and accordingly target available diagnostic technologies.