Complications after limb salvage surgeries for musculoskeletal malignancies: 10-year experience of the main sarcoma center in Bulgaria.

INTRODUCTION: Limb salvage surgery is currently the most frequently used treatment option in Bulgaria for individuals with musculoskeletal malignancies. Clinical data about complications from these procedures is limited in the country, with only a few studies currently available.

Evaluation of disease-specific quality of life and its influencing factors in Bulgarian patients with Graves' orbitopathy.

PURPOSE: Graves' orbitopathy (GO) profoundly affects patients' quality of life (QoL). Our aim was to assess QoL in patients with different forms of GO and to search for predictors of QoL. METHODS: This was a cross-sectional study involving 221 consecutive unselected GO patients (77.4% females, mean age 52 ± 11.6) referred to our clinic in the period 2017-2021. Detailed medical history was obtained from all patients, followed by hormonal and immunological testing and comprehensive ocular status. QoL was assessed by a disease-specific questionnaire (GO-QoL), consisting of two scales-one related to visual functioning (QoL-VF) and the other-to physical appearance (QoL-AP). The results were calculated by formula and expressed as percentages. RESULTS: Mild GO patients had significantly higher scores on both scales of GO-QoL compared to moderate-to-severe and sight-threatening GO patients (82.0 vs. 54.6% and 27.3% for QoL-VF; 70.1 vs. 54.4% and 36.9% for QoL-AP). Patients with active GO had significantly poorer QoL-VF (56.6 vs. 76.6%) and QoL-AP (53.1 vs. 67.5%) in comparison to patients with inactive GO. The stepwise linear regression analysis showed that the variables with major predictive value for QoL-VF were: CAS, diplopia score, visual acuity and severity of the symptoms (R2 = 0.44), whereas gender, CAS, diplopia score and proptosis best predicted QoL-AP (R2 = 0.39). CONCLUSIONS: The impact of GO on patients' QoL depends on the severity and activity of the disease. The clinical predictors of the impairment of QoL should be taken into account when considering the optimal adjunctive treatment approaches aiming to improve patients' QoL.

Occurrence and distribution of lost molars and furcation defects in a Bulgarian population: A retrospective three-dimensional study.

OBJECTIVES: To identify the ocuurrence, distribution, and factors associated with lost molars and furcation defects in a sample of the Bulgarian population. MATERIAL AND METHODS: The full mouth cone-beam computed tomography of 56 male and 57 female patients, aged between 19 and 84 years, were examined. A comprehensive evaluation was performed on a total of 675 molars-339 in maxilla and 336 in mandible. Associations with variables such as age, gender, and periodontal disease were analyzed. RESULTS: With aging the number of missing teeth and interradicular lesions increased. No significant links between gender and molar loss (p = .64) or gender and furcation involvement (p = .25) was found. Periodontitis was strongly associated with both studied dental problems (p < .001). The occurrence of furcation defects was more frequently observed in the maxilla than in the mandible. CONCLUSION: The occurrence and distribution of lost molars and furcation defects is substantial within the studied sample. Further investigation with a larger patient cohort is needed. Pertinent healthcare strategies to address the observed dental health issues also have to be developed.

Clinical and virological profile of locally acquired acute hepatitis E in South Bulgaria.

INTRODUCTION: Acute hepatitis E virus (HEV) infection is recognized as a zoonosis in several European countries. We describe the characteristics and outcomes of locally acquired acute HEV hepatitis. METHODOLOGY: A prospective study was conducted among adult patients with acute HEV hepatitis at the University Hospital in Plovdiv, South Bulgaria between January 2020 and May 2022. An acute HEV infection case was a patient with acute hepatitis and laboratory-confirmed anti-HEV IgM antibodies and/or HEV RNA in serum. Demographic data, clinical manifestations, laboratory test results, and outcomes were recorded. RESULTS: A total of 46 patients were selected. Median age of 65 years (interquartile range [IQR] 50.8-74.3). 28 (60.87%) were male. 22 (47.83%) had comorbidities such as diabetes (15), liver cirrhosis (3), hepatitis B virus infection (2), and malignancies (2). Of the 46, 18 (39.13%) patients were viremic and, HEV genotype 3 was detected. The median (IQR) serum alanine aminotransferase, aspartate aminotransferase, bilirubin, platelet, and international normalized ratio levels were 992 (495.8-1714.3) U/L, 715 (262.5-1259.3) U/L, 204 (132.3-235.5) µmol/L, 204 (132.3-235.5) ×109 L, and 1.0 (0.89-1.19), respectively. Six patients with underlying liver diseases had severe hepatitis. A young patient with osteoarthritis progressed to acute liver failure and died. The persistent HEV infection was ruled out in 2 malignant patients who tested HEV RNA negative three months after discharge. CONCLUSIONS: Acute HEV hepatitis is a diagnosis to consider after excluding other causes of acute viral hepatitis. A diagnostic workup should include timely testing for HEV to identify the most vulnerable to severe consequences.

Malnutrition in Institutionalized and Non-Institutionalized Neurologically Impaired Children in Bulgaria.

INTRODUCTION: The nutritional status of children with neurological impairment affects their health and quality of life. Bulgaria has many abandoned disabled children in residential homes. Lack of parental care puts them at risk for poor growth, suboptimal nutrition, and physical and mental development. Our study aims to identify factors associated with poor nutrition in Bulgarian children with neurological impairment living in different environments. METHODS: From January to December 2017, a cross-sectional study was conducted in northeastern Bulgaria. We recruited 109 residential and nonresidential children. The study included demographics, medical history, anthropometric measurements, biochemical tests, nutritional assessment, and gastrointestinal signs and symptoms. Data were analyzed with Jamovi 2.2.5 at a 0.05 significance level. Logistic regression was used to predict wasting in both environmental settings. RESULTS: About 70% of the neurologically impaired children living in residential settings have malnutrition based on weight-for-age Z-score, compared to 25% of the non-residential children. Prematurity, low gross motor function (as measured by the gross motor function classification system), pureed food consumption, birth before 37 weeks, and living in residential care homes are linked to poor nutrition. CONCLUSION: Neurologically impaired children have a poor nutritional state, especially those living in residential homes. The study underscores the pressing need for the allocation of additional nutrition resources to effectively address the nutritional and developmental needs of children with neurological disabilities in Bulgaria.

Molecular epidemiology and antimicrobial resistance of Haemophilus influenzae isolates from otitis media in Bulgaria.

Haemophilus influenzae is one of the main bacteria responsible for otitis media (OM) among children worldwide. We aimed to estimate the distribution of encapsulated and non-capsulated variants (NTHi), biotypes, antibiotic susceptibility, and molecular epidemiology of H. influenzae isolates recovered from pediatric OM cases in Bulgaria.Capsule detection was done by PCR for bexB gene, absent in NTHi. All encapsulated strains were subjected to PCR serotyping. MIC susceptibility testing was performed according to the criteria of EUCAST. MLST was conducted for all 71 OM isolates.The capsule detection and PCR - serotyping disclosed a predominance of NTHi (90.1%) and a few "a", "f", and "c" types. Biotype I was the most widespread (42.3%). ß-lactam resistance was found in 35.2% of the isolates. MLST represented heterogenic population structure, whereas the most represented clonal complexes belonged to ST-3, ST-57, ST-105, and ST-1426. 42.3% of the STs showed relatedness to globally represented clones, and 11.3% displayed affiliation to international type 2.Most of the H. influenzae isolates recovered from children with otitis media were non-typable strains from biotype I. The examined population structure was genetically diverse, with a predominance of international type 2 isolates.

Application of OMOP Common Data Model for Data Integration: The Bulgarian Diabetes Register.

This paper considers mapping of the Bulgarian Diabetes Register(BDR) onto OMOP Common Data Model (CDM). Research results are referenced and plans for analysis of drug shortages from federated data sources are outlined.

Anthropological study of dental indices in Bulgarian population.

INTRODUCTION: A number of derived quantities (called dental indices) that characterize the shape and size of the teeth are calculated between the absolute dimensions of the teeth (mesiodistal, vestibulo-oral, and height of the dental crown).

Mixed (multiple-genotype) Helicobacter pylori infections in Bulgarian patients.

The aim of the study was to evaluate the frequency and characteristics of mixed (multiple-genotype) Helicobacter pylori infections (MGIs) in 155 Bulgarian symptomatic patients (21 children and 134 adults). MGIs were common (36.1%), including double-strain (34.8%) and triple-strain infections (1.3%). None of the 8 ulcer patients harbored multiple subtypes. We detected 18 multiple allelic combinations, of which the most frequent subtypes (17.4%) were vacA s1as2 and vacA s1cs2. The 2 patients with triple-strain infections had vacA s1bs1cs2i1i2/iceA1A2 and vacA s1as1cs2 subtypes. They were both adult men with chronic gastritis and both were examined in 2022. The prevalence of MGIs (51.7%) was 2-fold higher in 2020 to 2022 than in 2015 to 2019 (26.3%). Putative factors for the increase may be the patient's characteristics and COVID-19 pandemic-associated factors. MGI rates corresponded to the high infection seroprevalence (72.4% in 2011) in Bulgaria. The evolution and clinical importance of mixed H. pylori infections merit extensive evaluation.

Genomic Epidemiology and Lineage Dynamics of SARS-CoV-2 in Bulgaria: Insights from a Three-Year Pandemic Analysis.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has brought about significant challenges worldwide. In this study, we present a comprehensive analysis of the genomic epidemiology and lineage dynamics of SARS-CoV-2 in Bulgaria over a three-year period. Through extensive genomic sequencing and data analysis, we investigated the evolution of the virus, the emergence of variants of concern (VOCs), and their impact on the country's pandemic trajectory. We also assessed the relationship between viral diversity and COVID-19 morbidity and mortality in Bulgaria. Our findings shed light on the temporal and spatial distribution of SARS-CoV-2 lineages and provide crucial insights into the dynamics of the pandemic in the country. The interplay between international travel and viral transmission plays a significant role in the emergence and dissemination of different SARS-CoV-2 variants. The observed proportions of exportation to various continents provide insights into the potential pathways through which these lineages spread globally. Understanding the genomic epidemiology of SARS-CoV-2 in Bulgaria is essential for formulating targeted public health strategies, enhancing vaccination efforts, and effectively managing future outbreaks.

Seroprevalence of herpes simplex virus type 1 and type 2 - data from a hospital-based study in Varna, northeastern Bulgaria, 2019-2021.

The purpose of the current study was to describe the prevalence of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in northeastern Bulgaria. From January 2019 to December 2021, we tested 1493 samples for anti-HSV-1 IgG and 817 samples for anti-HSV-2 IgG antibodies in the Virology Laboratory, "St. Marina" University Hospital, Varna, Bulgaria. HSV-1 was considerably more widespread, with an overall seroprevalence of 73.3% (95% CI: 71.0-75.5%), than HSV-2 infection, which showed a seropositive rate of 10.0% (95% CI: 8.1-12.4%). Age was the most significant risk factor for both infections, while gender had no role in herpes simplex seropositivity.

Nationwide analysis of the impact of COVID-19 in patients with a cardiovascular, oncological or chronic pulmonary disease in the context of an Eastern European country with a low vaccination rate, Bulgaria: March 2020-April 2022.

OBJECTIVE: This study focused on Bulgarian patient cohorts harbouring a single documented chronic comorbidity-cardiovascular pathology, an oncological disease or a chronic pulmonary diseases (CPD) comparing the outcomes in fully vaccinated and non-vaccinated populations classified by sex and age groups in ambulatory, hospital and intensive care unit (ICU) settings at the national level. DESIGN: Retrospective analysis SETTINGS, PARTICIPANTS AND OUTCOME MEASURES: In total, 1 126 946 patients with confirmed COVID-19, on a national level, were retrospectively analysed between March 2020 and April 2022, using data from the Ministry of Health's United Information Portal, launched in March 2020. RESULTS: Of all the confirmed 247 441 hospitalised cases of COVID-19, 67 723 (27.3%) had documented cardiovascular disease (CVD), 2140 (0.9%) had confirmed solid malignancy (regardless of stage) and 3243 (1.3%) had established CPD as their only chronic pathology. The number of cumulative deaths in each subgroup was 10 165 (in-hospital=5812 and ICU=4353); 4.0% vaccinated (410/10 165, p<0.001), 344 (in-hospital=196 and ICU=148), 4.9% vaccinated (17/344, p<0.001), 494 (in-hospital=287 and ICU=207) and 5.2% vaccinated (26/494, p<0.001), respectively. Statistical significance (p<0.001) was obtained in favour of reduced ambulatory, hospitalisation and both in-hospital and ICU-related mortality in the vaccinated cohorts, and BNT162b2 was the most effective at preventing mortality in all age groups. CONCLUSIONS: This retrospective analysis shows that patients vaccinated against COVID-19 demonstrated trends of reduced hospitalisations and premature mortality in patients with CVD, solid malignancy or CPD as a single comorbidity.

Assessment of health status and cardiovascular risk factors in a Roma population sample from South Bulgaria.

OBJECTIVES: Roma population is one of the major ethnic groups in the Central and Eastern Europe, having high rates of chronic diseases and associated risk factors related to their poor social conditions, unhealthy lifestyle and low educational level. The purpose of our study was to assess the health status of Roma from South Bulgaria by means of blood indicators and determine the prevalence of some cardiovascular (CV) risk factors in the Roma population sample. METHODS: The study group consisted of 60 Roma (23 men and 37 women), mean age 53.7 ± 15.9 years, and the control group consisted of 68 non-Roma from the majority population (29 men and 38 women), mean age 45.8 ± 12.2 years. The data were collected via questionnaire, anthropometric measures, and venous blood samples analyses after an overnight fasting. RESULTS: The Roma population subjects were slightly but significantly older compared to the non-Roma group and both study groups included more women. The fasting glucose, body mass index (BMI), triglycerides (TG), total cholesterol (TC), and LDL-cholesterol (LDL-C) levels were significantly higher, and HDL-cholesterol (HDL-C) levels were significantly lower in Roma compared to the control non-Roma group. The values of cardiovascular risk markers such as TC/HDL-C and TG/HDL-C ratios, atherogenic index of plasma (AIP) and lipoprotein combine index (LCI) were significantly higher in Roma compared to non-Roma subjects. The prevalence of obesity in Roma was 35%, diabetes mellitus was recorded in 16.7% of the entire Roma sample, and hyperglycaemia in non-diabetics was recorded in 32%. Hypercholesterolaemia was found in 90% and hypertriglyceridaemia was found in 88.3%. The prevalence of cardiovascular diseases (CVD) was high and was encountered in 71.7% of the Roma participants and most of the subjects (96.7%) reported family history of CVD. The studied population showed high smoking rates with 33.3% active smokers. CONCLUSIONS: Our study confirmed high prevalence of CV risk factors among Roma population, such as abnormal lipid profile parameters, obesity and heavy smoking and very high cardiovascular morbidity rate. Therefore, adequate measures and healthcare programmes aiming at the early identification, treatment and prevention of CVD risks among Roma are necessary.

First results of the growth disorders related twinning programme Partners4Growth implemented at the tertiary university pediatric endocrinology clinics in Bulgaria.

OBJECTIVES: Early diagnosis of childhood growth disorders, their timely and proper treatment are important for better outcomes.The aim of the present study was to assess the results of the first 18 months of the growth disorders related twinning programme "Partners4Growth" implemented at all tertiary university pediatric endocrinology clinics in Bulgaria. METHODS: In 2019, Partners4Growth started operation at 7 centres (4 experienced and 3 twin centres) with the main aim of aligning their practices in the shortest possible time. Education of twin centres' personnel was organized, equipment and methods for growth evaluation and follow-up were standardized. The approach was tested initially at one centre. At baseline and at the 18th month a questionnaire concerning diagnosis and management of recombinant human growth hormone (rhGH) requiring disorders was applied. RESULTS: A total of 104 new patients were diagnosed compared to 30 in the previous year. Of those, 91 started rhGH treatment - 65 (64 %) GH deficient, 12 (12 %) Turner syndrome, 7 (7 %) Prader-Willi syndrome patients, and 7 (7 %) born small for gestational age without postnatal catch-up, representing 35.8 % of all currently rhGH treated Bulgarian children. A better geographical coverage and more advanced diagnostic and management practices were achieved. CONCLUSIONS: Partners4Growth facilitated the alignment of the tertiary pediatric endocrinology centres competences thus leading to an improved diagnosis and treatment of growth disorders as well as better patients' access. For its short existence, the Programme increased significantly the number of new patients in the difficult times of COVID-19 pandemic thus justifying its continuation.

Medication Adherence among Patients with Diabetes Mellitus and Its Related Factors-A Real-World Pilot Study in Bulgaria.

Background and Objectives: The objective is to evaluate medication adherence level (MA) and the relevant determinants of MA among patients with type 2 diabetes mellitus (T2DM) monitored in ambulatory settings by general practitioners. Materials and Methods: A cross-sectional study was conducted among patients with T2DM monitored in a GP practice in Sofia, Bulgaria (September-December 2022). All patients were interviewed according to a predesigned questionnaire after granting informed consent. MA level was evaluated through the Morisky-Green four-item questionnaire, and health-related quality of life was evaluated by EQ-5D-5L and VAS (visual analogue scale). Data were aggregated and statistically evaluated. Results: The total number of observed patients was 93. Around 48.4% of patients were female, and 90.3% of patients were between 50 and 80 years of age. Multimorbidity was identified among 70% (n = 65) of the respondents. High and medium levels of MA were revealed in 64.51% and 33.3% of respondents, respectively. Patients treated with insulin secretagogues were most adherent to the therapy (n = 83.3%) in comparison with the other treatment groups. The onset of the disease, professional status, age, gender, number of therapies, and quality of life did not affect the level of MA (p > 0.05). VAS scores among nonsmokers (VAS = 63.16 ± 20.45 vs. 72.77 ± 14.3) and non-consumers of alcohol (VAS = 63.91 ± 19.34 vs. VAS = 72.54 ± 15.98) were statistically significant lower (p < 0.05). A significant related factor for MA was years lived with diabetes (OR = 3.039, 95% CI 1.1436-8.0759, p = 0.0258). The longer the disease duration, the more the odds for a high MA level increased. Conclusions: The number of nonadherent diabetic patients in Bulgaria is low, which might be evidence of patients' concern about their own health and understanding about the importance of prescribed therapy. Further comprehensive study with additional patients is required to confirm the results and investigate the predicting factors for a high level of MA.

First Insight into the Seroepidemiology of Hepatitis E Virus (HEV) in Dogs, Cats, Horses, Cattle, Sheep, and Goats from Bulgaria.

In recent years, hepatitis E virus (HEV) infection has been found to be widespread among different animal species worldwide. In Bulgaria, high HEV seropositivity was found among pigs (60.3%), wild boars (40.8%), and East Balkan swine (82.5%). The aim of the present study was to establish the seroprevalence of HEV among dogs, cats, horses, cattle, sheep, and goats in Bulgaria. In total, 720 serum samples from six animal species were randomly collected: dogs-90 samples; cats-90; horses-180; cattle-180; sheep-90; and goats-90. The serum samples were collected from seven districts of the country: Burgas, Kardzhali, Pazardzhik, Plovdiv, Sliven, Smolyan, and Stara Zagora. The animal serum samples were tested for HEV antibodies using the commercial Wantai HEV-Ab ELISA kit (Beijing, China). The overall HEV seroprevalence among different animal species from Bulgaria was as follows: dogs-21.1%; cats-17.7%; horses-8.3%; cattle-7.7%; sheep-32.2%; and goats-24.4%. We found the lowest overall HEV seropositivity in Plovdiv district (6.2%; 4/64; p = 0.203) and Smolyan district (8.8%; 4/45; p = 0.129), vs. the highest in Pazardzhik district (21.6%; 29/134; p = 0.024) and Burgas district (28.8%; 26/90; p = 0.062). To the best of our knowledge, this is the first serological evidence of HEV infection in dogs, cats, horses, cattle, sheep, and goats from Bulgaria. We found high HEV seropositivity in small ruminants (sheep and goats), moderate seropositivity in pets (dogs and cats), and a low level of seropositivity in large animals (horses and cattle). Previous Bulgarian studies and the results of this research show that HEV infection is widespread among animals in our country. In this regard, the Bulgarian health authorities must carry out increased surveillance and control of HEV infection among animals in Bulgaria.

Rhinovirus Genotypes Circulating in Bulgaria, 2018-2021.

Rhinoviruses (RV) are one of the most common causative agents of respiratory infections, with significant socioeconomic impact. RV infections are not notifiable in Bulgaria, and little is known about the different RV genotypes circulating in the country. This study aims to investigate the diversity of RV genotypes that were circulating in Bulgaria in the period 2018-2021 in samples from ILI/ARI patients. Genotype assignment was based on sequencing and phylogenetic analysis of the 5' untranslated region and the VP4-VP2 region. Out of a total of 1385 nasopharyngeal swabs tested, 166 were RV-positive (RV detection rate: 11.99% (166/1385)). Those with a cycle threshold <25 were selected for genotyping (n = 63). RV isolates were successfully genotyped and classified into 34 genotypes within Rhinovirus A (RV-A), Rhinovirus B (RV-B) and Rhinovirus C (RV-C) species. Presumptive recombination events between the 5'UTR and VP4-VP2 regions were detected in three of the isolates. RV-A and RV-C were the prevalent RV species, with significantly more frequent detections of RV-A in the years before the COVID-19 pandemic compared to the post-pandemic period, when RV-C prevailed. The present study is the first to determine RV genotypes in Bulgaria and the circulation of RV-C has been described for the first time in the country.

Endometrial carcinoma in patients under 40 years of age: insights from the Bulgarian Cancer Registry.

OBJECTIVES: We aimed to investigate the overall survival (OS) of young women with endometrial cancer (EC) in Bulgaria and the impact of histological type on survival. MATERIAL AND METHODS: This is a population-wide retrospective study of patients with EC (≤ 40 years at diagnosis) registered at Bulgarian National Cancer Registry (BNCR) between 1993 and 2020. Patients were re-classified according to the 8th edition of the TNM classification. RESULTS: In total, 30 597 patients were registered and histologically confirmed with malignant tumors of the uterine body. From that, 29 065 of them (95%) had ECs, and the rest had sarcomas. Around 1.64% of all malignant tumors of the uterine body are diagnosed in women under the age of 40. Most of them are diagnosed in the early stage. There was no significant difference in median OS for patients diagnosed before or after 2003. In recent years there was a slight improvement in survival and patients from the last cohort of this study had a 5-year survival rate of 92.5%. Patients with favorable pathology (T1, G1/2) had no lymph node involvement at the time of diagnosis and their 10-year survival rate was 94%. CONCLUSIONS: EC in young women is a rare disease. In most cases, patients are diagnosed in early stageT1, G1/2, N0 and their prognosis is excellent. However, the lack of improvement of OS of young patients with EC in the last three decades shows the need for treatment optimization.

[The short characteristic of particular aspects of of public health of Greece, Spain, Bulgaria].

The article presents short characteristic of relevant scientific publications concerning some aspects of public health of Greece, Spain and Bulgaria and presented in the PubMed database in 2014-2020. The rather high indicators of life expectancy, low values of maternal and infant mortality are marked. The best results are established in Spain. The high prevalence of chronic non-communicable diseases and their risk factors persists in countries analyzed, especially in Bulgaria and Greece. The health care systems of Greece, Spain and Bulgaria implement projects of digital transformation of medical care support. The most successful in this respect is Spain, while in Bulgaria and Greece information systems in health care remain fragmented.

Genotypic and phenotypic insights into virulence factors of nosocomial Stenotrophomonas maltophilia isolates collected in Bulgaria (2011-2022).

The present study aimed to explore the virulence characteristics in 221 Bulgarian nosocomial Stenotrophomonas maltophilia isolates (2011-2022) via screening for the presence of virulence genes, their mutational variability, and the corresponding enzyme activity. PCR amplification, enzymatic assays, whole-genome sequencing (WGS), and biofilm quantification on a polystyrene plate were performed. The incidence of virulence determinants was as follows: stmPr1 (encoding for the major extracellular protease StmPr1) 87.3%, stmPr2 (minor extracellular protease StmPr2) 99.1%, Smlt3773 locus (outer membrane esterase) 98.2%, plcN1 (non-hemolytic phospholipase C) 99.1%, and smf-1 (type-1 fimbriae, biofilm-related gene) 96.4%. The 1621-bp allele of stmPr1 was most frequently found (61.1%), followed by the combined allelic variant (17.6%), stmPr1-negative genotype (12.7%), and 868-bp allele (8.6%). Protease, esterase, and lecithinase activity was observed in 95%, 98.2%, and 17.2% of the isolates, respectively. The WGS-subjected isolates (n = 9) formed two groups. Five isolates possessed only the 1621-bp variant of stmPr1, higher biofilm formation ability (Optical Density at λ = 550 nm (OD550): 1.253-1.789), as well as a low number of mutations in the protease genes and smf-1. Three other isolates had only the 868-bp variant, weaker biofilm production (OD550: 0.788-1.108), and higher number of mutations within these genes. The only weak biofilm producer (OD550 = 0.177) had no stmPr1 alleles. In conclusion, the similar PCR detection rates did not allow differentiation of the isolates. In contrast, WGS permitted stmPr1 alleles-based differentiation. To the best of our knowledge, this is the first Bulgarian study presenting genotypic and phenotypic insights into virulence factors of S. maltophilia isolates.