Gergana Lengerova

Dr. Gergana Lengerova

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Research Focus & Metrics

Academic Career Length

8Years (2019-Present)

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

Representative Publications

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30 September 2025 in Antibiotics
Verified
Journal Article
Open access
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MRMilena Yancheva Rupcheva
Milena Yancheva Rupcheva
Kostadin Rangelov KostadinovKostadin Rangelov Kostadinov
Kostadin Rangelov Kostadinov
YKYordan Kalchev
Yordan Kalchev
PGPetya Gardzheva
Petya Gardzheva
EHEli Hristozova
Eli Hristozova
MPMichael M. Petrov
Michael M. Petrov
Background: Urinary tract infections (UTIs) are among the most common hospital- and community-acquired infections, creating a substantial healthcare burden due to recurrence, complications, and rising antimicrobial resistance. Accurate diagnosis and timely antimicrobial therapy are essential. This study aimed to identify trends in the etiology, treatment, and resistance patterns of UTIs through a retrospective analysis of urine isolates processed at the Laboratory of Microbiology at University Hospital St. George in Plovdiv, the largest tertiary care and reference microbiology center in Bulgaria, between 2017 and 2022. Materials and Methods: A retrospective single-center study was performed at the hospital’s Microbiology Laboratory. During the study period, 74,417 urine samples from 25,087 hospitalized patients were screened with the HB&L UROQUATTRO system. Positive specimens were cultured on blood agar, Eosin-Methylene Blue, and chromogenic media. Identification was performed using biochemical assays, MALDI-TOF MS, and the Vitek 2 Compact system. Antimicrobial susceptibility testing included disk diffusion, MIC determination, broth microdilution (for colistin), and Vitek 2 Compact, interpreted according to EUCAST standards. Descriptive analysis and temporal resistance trends were evaluated with regression models, and interrupted time-series analysis was applied to assess COVID-19-related effects. Results: Out of 10,177 isolates, Gram-negative bacteria predominated (73%), with Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis as the leading pathogens. Among Gram-positives, Enterococcus faecalis was the most frequent. In the post-COVID-19 period, ESBL production increased in E. coli (34–38%), K. pneumoniae (66–77%), and P. mirabilis (13.5–24%). Carbapenem resistance rose in K. pneumoniae (to 40.6%) and P. aeruginosa (to 24%), while none was detected in E. coli. Colistin resistance increased in K. pneumoniae but remained absent in E. coli and P. aeruginosa. High-level aminoglycoside resistance in E. faecalis was stable (~70%), and vancomycin resistance in E. faecium rose from 4.6% to 8.9%. Conclusions: Both community- and hospital-acquired UTIs in Southeastern Bulgaria are increasingly linked to multidrug-resistant pathogens, particularly ESBL-producing and carbapenem-resistant Enterobacterales. Findings from the region’s largest referral center highlight the urgent need for continuous surveillance, rational antibiotic use, and novel therapeutic approaches.

31 August 2021 in Folia Medica
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Journal Article
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PVPetar Vasilev
Petar Vasilev
Mariya IvanovskaMariya Ivanovska
Mariya Ivanovska
GLGergana Lengerova
Gergana Lengerova
APAtanaska Petrova
Atanaska Petrova
EHEli Hristozova
Eli Hristozova
MSMariyana Stoycheva
Mariyana Stoycheva
Most cases of acute diarrhea in adults are of infectious etiology, likely viral and self-limited. Among those with severe diarrhea, however, bacterial causes are responsible for most cases.Apart from the standard stool cultures, to increase the positive yield a novel multiplex molecular test can be performed simultaneously. The authors present a patient with recurrent diarrhea and detection of Aeromonas hydrophila by culturing and Rotavirus and Clostridioides difficile by multiplex molecular test. They discuss and justify which is the most likely actionable pathogen. Good communication between the physicians and interpretation on the multiple positive results in the context of clinical picture and the test employed were important for a better management and favourable outcome of the patient.

28 April 2026 in Microorganisms
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Journal Article
Open access
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Ralitsa RaychevaRalitsa Raycheva
Ralitsa Raycheva
GLGergana Lengerova
Gergana Lengerova
MPMichael M. Petrov
Michael M. Petrov
TKTodor Vesselov Kantardjiev
Todor Vesselov Kantardjiev
Bloodstream infections (BSIs) are associated with substantial morbidity, mortality, and healthcare costs. Conventional diagnostics are limited by delayed results, often postponing appropriate antimicrobial therapy. This review aimed to evaluate the clinical and economic value of rapid microbiological diagnostics in BSI management. A state-of-the-art evidence synthesis was conducted using structured searches of PubMed/MEDLINE, Scopus, Web of Science, EconLit, and Google Scholar (2013–2025). Eligible studies included economic evaluations and clinical studies reporting downstream economic or resource-use outcomes. Screening and data extraction were performed by two reviewers, and findings were narratively synthesized. Fifty-nine studies were included. Rapid diagnostics consistently reduced time to pathogen identification and targeted therapy compared to conventional methods. Molecular platforms provided results within hours, while MALDI-TOF enabled identification within 30–60 min after culture positivity. Clinical benefits included earlier therapy optimization, reduced mortality, and shorter hospital stays, particularly when combined with antimicrobial stewardship programs (ASPs). Economic evaluations demonstrated improved cost-effectiveness, including reduced hospitalization, ICU utilization, and antimicrobial costs. MALDI-TOF with stewardship showed notable cost savings and improved outcomes. However, results varied depending on implementation context, infrastructure, and workflow integration. Rapid microbiological diagnostics offer significant clinical and economic benefits in BSI management, particularly when integrated with stewardship programs. Context-specific implementation is essential to maximize their value across healthcare systems.

1 January 2022 in Open Access Macedonian Journal of Medical Sciences
Verified
Journal Article
Open access
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YKYordan Kalchev
Yordan Kalchev
APAtanaska Petrova
Atanaska Petrova
GLGergana Lengerova
Gergana Lengerova
IIIvan Ivanov
Ivan Ivanov
MMMariyana Murdjeva
Mariyana Murdjeva
Background: Elizabethkingia spp. are Gram-negative, non-spore-forming bacteria that used to be rarely encountered but now they are of growing clinical significance. Furthermore, the diagnostic challenges to identification impede the complete elucidation of their epidemiology and association with human diseases. Case report: A 64-year-old man with liver cirrhosis due to alcohol abuse presented with fatigue, abdominal swelling, and bilateral scrotal edema. A peritoneal fluid sample was cultured and subject to a number of identification methods – API 20 NE (bioMerieux), automated Vitek-2 Compact (bioMerieux), MALDI-TOF MS (Vitek-MS, bioMerieux), and 16S rRNA gene sequencing. A final diagnosis of bacterascites was made on the basis of clinical, laboratory, and microbiological findings. Conclusion: To the best of our knowledge this is the first report of Elizabethkingia miricola being cultured from a peritoneal fluid sample in an immune-compromised host thus pointing to the emerging pathogenic role of the bacterium in patients with liver cirrhosis and ascites.

2 December 2023 in Microorganisms
Verified
Journal Article
Open access
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YKYordan Kalchev
Yordan Kalchev
HUHristina Urdzhanova
Hristina Urdzhanova
SSStefan Stanev
Stefan Stanev
BCBogomila Cheshmedzhieva
Bogomila Cheshmedzhieva
Maria Radoslavova PavlovaMaria Radoslavova Pavlova
Maria Radoslavova Pavlova
.M.Marianna Atanassova Murdjeva
.Marianna Atanassova Murdjeva
Yersinia enterocolitica is a foodborne pathogen, mainly associated with disorders involving the gastrointestinal tract, including diarrhea, ileitis, and mesenteric lymphadenitis. Extraintestinal presentation is uncommon in healthy individuals, but bacteremia is reported in immunocompromised hosts. We present a 74-year-old male with Y. enterocolitica serogroup O:3 bacteremia who complicated to rupture of an abdominal aortic aneurysm. With the current case report, we aimed to emphasize the association of Y. enterocolitica bacteremia with abdominal aortic aneurysm rupture. Better surveillance is needed, not only to reduce morbidity and mortality but also to update current epidemiological data on the incidence of such associations.

30 June 2023 in Folia Medica
Verified
Journal Article
Open access
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AAAndreana Angelova
Andreana Angelova
MAMariya Atanasova
Mariya Atanasova
KKKostadin Ketev
Kostadin Ketev
ZHZeyra Halil
Zeyra Halil
IPIvanka Paskaleva
Ivanka Paskaleva
MMMariana Murdjeva
Mariana Murdjeva
The Coronavirus Disease 2019 (COVID-19) caused by a novel coronavirus (SARS-CoV-2) affects mainly older adults. Those with comorbidities are at a higher risk of severe disease and even death. The symptomatic infection rate of children is lower, manifestations are milder, and severe forms are scarce. We present here two children with severe COVID-19 and a respiratory syncytial virus, with the goal of emphasizing the possibility of coinfection with a severe course and a different result. The microbiological diagnosis was made using multiplex PCR. This assay not only provided an early and accurate diagnosis but also aided in the implementation of contact precautions. Further research should be done to determine the influence of coinfection on the clinical course and outcome of pediatric patients.