Turmeric and curcumin as adjuncts in controlling Helicobacter pylori-associated diseases: A narrative review

Non-antibiotic adjuncts may improve Helicobacter pylori infection control. Our aim was to emphasize curcumin benefits in controlling H. pylori infection. We discussed publications in English mostly published since 2020 using keyword search. Curcumin is the main bioactive substance in turmeric. Curcumin inhibited H. pylori growth, urease activity, three cag genes, and biofilms through dose- and strain-dependent activities. Curcumin also displayed numerous anticancer activities such as apoptosis induction, anti-inflammatory and anti-angiogenic effects, caspase-3 upregulation, Bax protein enhancement, p53 gene activation, and chemosensitization. Supplementing triple regimens, the agent increased H. pylori eradication success in three Iranian studies. Bioavailability was improved by liposomal preparations, lipid conjugates, electrospray-encapsulation, and nano-complexation with proteins. The agent was safe at doses of 0.5->4 g daily, the most common (in 16% of the users) adverse effect being gastrointestinal upset. Notably, curcumin favorably influences the intestinal microbiota and inhibits Clostridioides difficile. Previous reports showed inhibitory effect of curcumin on H pylori growth. Curcumin may become an additive in the therapy of H. pylori infection, an adjunct for gastric cancer control, and an agent beneficial to the intestinal microbiota. Further examination is necessary to determine its optimal dosage, synergy with antibiotics, supplementation to various eradication regimens, and prophylactic potential.

A Review of the Impact of Streptococcal Infections and Antimicrobial Resistance on Human Health

Streptococcus pneumoniae, Streptococcus pyogenes (GAS), and Streptococcus agalactiae (GBS) are bacteria that can cause a range of infections, some of them life-threatening. This review examines the spread of antibiotic resistance and its mechanisms against antibiotics for streptococcal infections. Data on high-level penicillin-resistant invasive pneumococci have been found in Brazil (42.8%) and Japan (77%). The resistance is caused by mutations in genes that encode penicillin-binding proteins. Similarly, GAS and GBS strains reported from Asia, the USA, and Africa have undergone similar transformations in PBPs. Resistance to major alternatives of penicillins, macrolides, and lincosamides has become widespread among pneumococci and streptococci, especially in Asia (70-95%). The combination of several emm types with erm(B) is associated with the development of high-level macrolide resistance in GAS. Major mechanisms are ribosomal target modifications encoded by erm genes, ribosomal alterations, and active efflux pumps that regulate antibiotic entry due to mefA/E and msrD genes. Tetracycline resistance for streptococci in different countries varied from 22.4% in the USA to 83.7/100% in China, due to tet genes. Combined tetracycline/macrolide resistance is usually linked with the insertion of ermB into the transposon carrying tetM. New quinolone resistance is increasing by between 11.5 and 47.9% in Asia and Europe. The mechanism of quinolone resistance is based on mutations in gyrA/B, determinants for DNA gyrase, or parC/E encoding topoisomerase IV. The results for antibiotic resistance are alarming, and urgently call for increased monitoring of this problem and precautionary measures for control to prevent the spread of resistant mutant strains.

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.

A Case-Control Study of the Fokl Polymorphism of the Vitamin D Receptor Gene in Bulgarians With Lumbar Disc Herniation

BACKGROUND

The present study investigates whether vitamin D receptor (VDR) gene polymorphisms play a role in intervertebral disc degeneration (IDD), a common cause of low back pain (LBP) and reduced quality of life. Specifically, we examined the FokI VDR polymorphism and its potential association with lumbar disc herniation (LDH) in patients from Bulgaria. Previous studies have suggested a link between mutations in the VDR gene and IDD.

METHODS

We investigated whether a potential connection between VDR polymorphisms and LDH was present by comparing the FokI polymorphism of 60 selected patients (25 to 60) with LDH and 60 healthy volunteers within the same age range. We used polymerase chain reaction to assess the phenotype of the examined subjects and statistical tests to evaluate whether the obtained results were statistically significant.

RESULTS

The performed genetic and statistical analyses reviewed significant differences in genotypic frequencies between the patient group and healthy volunteers. The frequency of the F allele is notably higher in patients with LDH (80%) compared to volunteers (52%), while the f allele is more common among patients (86.6%) than volunteers (100%).

CONCLUSION

This study strongly suggests that expression of the F allele of the VDR gene may increase the susceptibility of developing LDH, while having the f allele could potentially have a protective effect. Our results shed light on the underlying complex mechanisms contributing to the development of LDH.

Clostridioides difficile resistance to antibiotics, including post-COVID-19 data

INTRODUCTION

Updating data on Clostridioides difficile antibiotic resistance is important for treatment improvement of C. difficile infections (CDIs).

AREAS COVERED

Results from 20 countries were included. The mean resistance to 2 mg/l vancomycin, 2 mg/l metronidazole, 4 mg/l moxifloxacin, and 4 mg/l clindamycin was 4.7% (0 to ≥ 26% in two studies), 2.6% (0 to ≥ 40% in 3 studies), 34.9% (6.6->80%), and 61.0% (30->90%), respectively. Resistance to erythromycin (>60-88%), rifampin (>23-55.0%), imipenem (0.6 to > 78% in a clone), tigecycline (0-<5.0%), and fidaxomicin (0-2%) was also found. Resistance to ≥ 5 antibiotics of different classes was reported in some countries. High resistance and multidrug resistance were observed in hypervirulent and epidemic strains. Although only 1% of COVID-19 patients had CDIs, the proportion might be underestimated.

EXPERT OPINION

C. difficile antimicrobial susceptibility varied by country/region, study period, and circulating ribotypes. For CDI treatment, fidaxomicin (preferably) or vancomycin is recommended, while metronidazole is suitable for mild infections. New approaches, including biotherapeutics (Rebyota), strains, antibiotics (ridinilazole and ibezapolstat), and monoclonal antibodies/cocktails merit further evaluation. Because of the resistance rate variations, C. difficile antibiotic susceptibility should be regularly monitored. Post-COVID-19 resistance should be separately presented. Some discrepancies between vancomycin and metronidazole results need to be clarified.

Anaerobes in specific infectious and noninfectious diseases: new developments

With the buildup of new research data, newer associations between anaerobic bacteria and diseases/conditions were evaluated. The aim of the mini-review was to draw attention and to encourage further multidisciplinary studies of the associations. We considered microbiome-disease correlations such as a decrease of fecal Faecalibacterium prausnitzii abundance in inflammatory bowel disease (IBD) and IBD recurrence, suggesting that F. prausnitzii could be a good biomarker for IBD. A link of subgingival Porphyromonas gingivalis with cardiovascular diseases was reported. Decreased Roseburia abundance was observed in the gut of Alzheimer's and Parkinson's disease patients. Akkermansia muciniphila was found to improve adipose/glucose metabolism, however, its intestinal abundance was observed in neurodegenerative diseases as well. Severe Clostridioides difficile infections have been reported in neonates and young children. Carcinogenic potential of anaerobes has been suggested. Fusobacterium nucleatum was implicated in the development of oral and colorectal cancer, Porphyromonas gingivalis and Tannerella forsythia were linked to esophageal cancer and Cutibacterium acnes subsp. defendens was associated with prostate cancer. However, there are some controversies about the results. In a Swedish longitudinal study, neither P. gingivalis nor T. forsythia exhibited oncogenic potential. The present data can enrich knowledge of anaerobic bacteria and their multifaceted significance for health and disease and can draw future research directions. However, more studies on large numbers of patients over prolonged periods are needed, taking into account the possible changes in the microbiota over time.

Molecular Epidemiology of Bulgarian Clinically Significant Staphylococcus aureus Isolates

Severe infections due to highly virulent and resistant Staphylococcus aureus pose a serious health threat in Bulgaria and worldwide. The purpose of this study was to explore the clonal spread of recent clinically significant methicillin-susceptible S. aureus (MSSA) isolates from inpatients and outpatients treated in three university hospitals in Sofia, Bulgaria, during the period 2016-2020 and evaluate the relationship between their molecular epidemiology, virulence profiling, and antimicrobial resistance. A total of 85 isolates (invasive and noninvasive) were studied using RAPD analysis. Ten major clusters (A-K) were identified. The first major cluster A (31.8%) was found to be predominant during 2016 and 2017 and was widespread in two hospitals, unlike its case in the following years, when it was found to be replaced by newer cluster groups. All MSSA members of the second most common cluster F (11.8%) were recovered from the Military Medical Academy, mainly during 2018-2020, and were determined to be susceptible to all other groups of antimicrobials, except for penicillins without inhibitors because they harboured the blaZ gene. The newer cluster I, with 9.4% of the isolates absent in 2016-2017, showed significantly higher virulence and macrolide resistance (42.9%) due to ermB and ermC. All the isolated MSSA in groups F and I were nosocomial and mostly invasive. In conclusion, this 5-year study demonstrates the molecular epidemiology of MSSA infections in three Bulgarian hospitals. Findings can be helpful for the understanding of staphylococcal infection distribution in hospital settings and their prevention.

Clostridioides difficile, a New “Superbug”

Clostridioides difficile is a Gram-positive, spore-forming, anaerobic bacterium. The clinical features of C. difficile infections (CDIs) can vary, ranging from the asymptomatic carriage and mild self-limiting diarrhoea to severe and sometimes fatal pseudomembranous colitis. C. difficile infections (CDIs) are associated with disruption of the gut microbiota caused by antimicrobial agents. The infections are predominantly hospital-acquired, but in the last decades, the CDI patterns have changed. Their prevalence increased, and the proportion of community-acquired CDIs has also increased. This can be associated with the appearance of hypervirulent epidemic isolates of ribotype 027. The COVID-19 pandemic and the associated antibiotic overuse could additionally change the patterns of infections. Treatment of CDIs is a challenge, with only three appropriate antibiotics for use. The wide distribution of C. difficile spores in hospital environments, chronic persistence in some individuals, especially children, and the recent detection of C. difficile in domestic pets can furthermore worsen the situation. “Superbugs” are microorganisms that are both highly virulent and resistant to antibiotics. The aim of this review article is to characterise C. difficile as a new member of the “superbug” family. Due to its worldwide spread, the lack of many treatment options and the high rates of both recurrence and mortality, C. difficile has emerged as a major concern for the healthcare system.

Molecular Screening for High-Risk Human Papillomaviruses in Patients with Periodontitis

Members of the Papillomaviridae family account for 27.9-30% of all infectious agents associated with human cancer. The aim of our study was to investigate the presence of high-risk HPV (human papilloma virus) genotypes in patients with periodontitis and a pronounced clinical picture. To achieve this goal, after proving the bacterial etiology of periodontitis, the samples positive for bacteria were examined for the presence of HPV. The genotype of HPV is also determined in samples with the presence of the virus proven by PCR (polymerase chain reaction). All positive tests for bacteria associated with the development of periodontitis indicated the presence of HPV. There was a statistically significant difference in HPV positive results between the periodontitis positive target group and the control group. The higher presence of high-risk HPV genotypes in the target group, which was also positive for the presence of periodontitis-causing bacteria, has been proven. A statistically significant relationship was established between the presence of periodontitis-causing bacteria and high-risk strains of HPV. The most common HPV genotype that tests positive for bacteria associated with the development of periodontitis is HPV58.

Geographic distribution of antibiotic resistance of Helicobacter pylori: A study in Bulgaria

Prevalence of antibiotic resistant Helicobacter pylori was compared between 50 patients living outside the capital city and 50 matched pairs of capital city residents (CCRs). H. pylori isolates from 2018 to 2022 were included. Resistance rates in CCRs and those living elsewhere were 4.0 and 6.0% to amoxicillin, 48.0 and 42.0% to metronidazole, 30 and 30% to clarithromycin, and 4.0 and 4.0% to tetracycline, respectively. Levofloxacin resistance was higher (38.0%) in the capital city vs 20.0% (P = 0.047) in the country. Odd ratio for levofloxacin resistance between pair-matched groups was 2.45 (95% CI, OR 1.0-6.02, P value = 0.05) and relative risk for fluoroquinolone resistance was 1.90 (95% CI for RR 0.98-3.67) for CCRs vs residents in other regions. Resistance rates to levofloxacin and clarithromycin were worryingly high in our study, most probably due to the high quinolone consumption (2.86 DDD/day in 2017) in Bulgaria and the increase in macrolide, lincosamide and streptogramin consumption, especially of azithromycin, by >42% with the start of COVID-19 pandemic. Briefly, antibiotic resistance of H. pylori has a dynamic change, and it can display different patterns in certain geographic regions. The results imply that antibiotic consumption should be carefully controlled and unjustified use of levofloxacin should be restricted, especially in some large cities. Antibiotic policy should be further strengthened and regular monitoring of resistance in various geographic regions is needed for treatment optimization.

Evolution of Helicobacter pylori Resistance to Antibiotics: A Topic of Increasing Concern

Antibiotic resistance among Helicobacter pylori strains is the major cause of eradication failure. Resistance prevalence is dynamic and can greatly vary among countries over the years. We revealed H. pylori resistance trends for five antibiotics in 14 countries through articles predominantly published in 2018-2022, since the latest data can best show the most recent trends in resistance evolution. Amoxicillin resistance generally exhibited no evolution, yet it increased in Bulgaria, Iran, China, and Vietnam. Metronidazole resistance exhibited different trends, including an increase, a decrease and no evolution in six, three, and five studies, respectively. Clarithromycin resistance increased in Australia, Belgium, Bulgaria, Italy, Iran, and Taiwan, but remained stable in France, Spain, Russia, China, Chile, and Colombia. Tetracycline resistance was low and stable except in Iran. Levofloxacin resistance increased in four European and six other countries/regions, without significant increases in France, Spain, and Chile. In Chile, triple resistance also increased. In countries such as France and Spain, resistance to most antibiotics was stabilized, while in Bulgaria, Belgium, Iran and Taiwan, resistance to three or more agents was reported. Use of non-recommended regimens, national antibiotic consumption, patient's compliance, host factors, strain virulence, migrations, and azithromycin overuse during the COVID-19 pandemic can influence resistance evolution. New drugs, eradication regimens and diagnostic methods, such as next-generation sequencing can improve H. pylori infection control.

First detection of a colistin-resistant Klebsiella aerogenes isolate from a critically ill patient with septic shock in Bulgaria

Colistin is considered as the last-line antibiotic for the treatment of infections caused by extensively drug-resistant Gram-negative pathogens belonging to the ESKAPE ( Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) group. The present study aimed to explore the colistin resistance mechanisms of a Klebsiella aerogenes (formerly Enterobacter aerogenes) isolate (Kae1177-1bg) obtained from a Bulgarian critically ill patient with septic shock in 2020. Antimicrobial susceptibility testing and whole-genome sequencing using DNA nanoball technology were performed. The resulting read pairs were used for draft genome assembly, MLST analysis and mutation screening in the pmrA/B, phoP/Q, and mgrB genes. Kae1177-1bg demonstrated high-level resistance to colistin, resistance to 3rd generation cephalosporins and susceptibility to all other antibiotics tested. In our strain a CMY-2-type class C cephalosporinase was the only β-lactamase identified. No mobile colistin resistance (mcr) genes were detected. A total of three missense variants in the genes for the two-component PmrA/PmrB system were identified. Two of them were located in the pmrB (pR57K and pN275K) and one in the pmrA gene (pL162M). The pN275K variant emerged as the most likely cause for colistin resistance because it affected a highly conservative position and was the only nonconservative amino acid substitution. In conclusion, to the best of our knowledge, this is the first documented clinical case of a high-level colistin-resistant K. aerogenes in Bulgaria and the first identification of the nonconservative amino acid substitution pN275K worldwide. Colistin-resistant Gram-negative pathogens of ESKAPE group are serious threat to public health and should be subjected to infection control stewardship practices.

Molecular epidemiology, virulence and antimicrobial resistance of Bulgarian methicillin resistant Staphylococcus aureus isolates

Background

Severe infections of virulent methicillin-resistant Staphylococcus aureus (MRSA) are a serious health problem. The present study aimed to investigate clonal spread, virulence and antimicrobial resistance rates of Bulgarian MRSA isolates in 2016–2020.

Methods

Molecular identification and mecA gene detection were performed with PCR. Clonal relatedness was evaluated by RAPD PCR and MLST. MRSA epidemiology, virulence and resistance patterns were investigated by PCR.

Results

All 27 isolates were identified as S. aureus and were mecA positive, and all were susceptible to linezolid, tigecycline and vancomycin. The toxin genes hlg (in 92.6% of isolates), seb (77.8%), sei (77.8%), seh (59.3%), sej (55.6%), and seg (48.1%), were frequently found among the isolates. Epidemiological typing by RAPD identified 4 clones (16 isolates) and 11 were with a unique profile. MLST analysis of the same MRSA isolates showed five MLST clonal complexes and 11 ST types, including CC5 (33.3%) (ST5, ST221, ST4776), CC8 (22.2%) (ST8, ST239, ST72), CC15 (ST582), CC22 (14.8%) (ST217, ST5417), CC30 (ST30) CC398 (ST398), and CC59 (ST59). The isolates from CC5 showed higher virulence potential and almost all were macrolide resistant (ermB or ermC positive). CC8 isolates showed higher level of resistance.

Conclusion

To the best of our knowledge, this study is the first describing the clonal spreading of Bulgarian MRSA and the association with their virulence and resistance determinants. Monitoring of MRSA epidemiology, resistance and virulence profile can lead to better prevention and faster therapeutic choice in cases of severe infections.

Investigation of multidrug-resistant Helicobacter pylori in pediatric patients: A Bulgarian study and literature data

Antibiotic resistance of Helicobacter pylori strains from 106 symptomatic children was evaluated according to EUCAST breakpoints and rate of multidrug resistance (MDR) was analyzed. Overall resistance rates were amoxicillin 7.5%, metronidazole 25.5%, clarithromycin 34.0% and ciprofloxacin 14.1%. There were no significant differences in resistance rates according to patients' age (2-6 and 7-18 years) and sex. Combined resistance rate was 19.8%, including double, triple, and quadruple resistance in 13.2% (14 strains), 5.7% (6) and 0.9% (1) of the strains, respectively. MDR was found in 5.9% (5/84) of the children with gastritis and in two of the four children with celiac disease. The MDR was present in three children aged 4-6 years and in four children aged 10-17 years. The total MDR rate (6.6%) in Bulgarian children in 2012-2021 was higher than those in other studies based on EUCAST breakpoints such as those in pediatric patients in Slovenia in 2011-2014 (3.8%), Lithuania in 2013-2015 (0%) and Spain in 2014-2019 (0%), although being lower than those (20.7% in the untreated and 47.0% in the treated children) in China in 2019. In brief, it is of concern that MDR can strongly limit the choice of H. pylori therapy of one out of fifteen Bulgarian children and that overall resistance to both metronidazole and clarithromycin can hinder the treatment of 15.1% of the pediatric patients. Susceptibility-guided tailored eradication therapy of H. pylori infection should be more frequently implemented in the symptomatic children to avoid risks of both the infection itself and multiple antibiotic treatments.

ANTIMICROBIAL EFFECT OF A MEANS FOR ENZYME EXCAVATION (BRIX 3000) AND PHOTODYNAMIC THERAPY IN CARIOUS LESIONS OF PRIMARY TEETH – IN VITRO EXPERIMENT

The selective removal of the caries dentin via enzyme methods for excavation appears to be an alternative to the conventional treatment of carious lesions in childhood. Photodynamic therapy is an effective alternative for the reduction of cariesogenic microorganisms. Brix 3000 is an enzyme-based material for excavation of carious dentin. Aim: To study the antimicrobial effect of means for enzyme excavation (Brix 3000) and photodynamic therapy with FotoSan 630 Intro Kit to the two main cariesogenic microorganisms – S. mutans and L. acidophilus, in vitro experiment; Materials and Methods: Eighty plates were prepared: group 1- 20 plates only with Brix 3000; group2 – 20 plates only with FotoSan; group 3 – 20 plates with a combination of Brix 3000 and FotoSan; group 4 – 20 plates without an active agent. In the agar of each plate, three 7 mm wells in diameter were made, where the Brix 3000 gel was placed, as well as discs soaked with the dye and irradiated with FotoSan and a combination of them. After 24 hours, the zone of inhibition was measured. Results: Compared to the control group, Brix 3000 and FotoSan have a defined antimicrobial activity against S. mutans and Lactobacillus spp. By combining the two materials, their antimicrobial activity significantly increases. S. mutans shows greater resistance compared to Lactobacillus spp. Conclusion: A combination of enzyme-based excavation and photodynamic therapy could be used successfully in the treatment of carious lesions in primary teeth.

COMPARATIVE STUDY OF ANTIBACTERIAL ACTIVITY OF PHOTOACTIVATED DISINFECTION WITH FOTOSAN AND STANDARD ENDODONTIC TREATMENT

Introduction: The purpose of endodontic treatment is to eliminate the bacterial infection in the root canal system and allow healing of apical periodontitis. Sometimes the anatomical complexity of the root canal system makes complete removal of bacteria almost impossible even if the conventional methods of chemo-mechanical debridement are performed strictly according to the protocol. So additional methods of root canal disinfection can be applied such as photoactivated disinfection (PAD). Purpose: The aim of our study was to compare the antibacterial activity of PAD with FotoSan, and conventional endodontic therapy in the treatment of infected root canals. Materials and methods: The study involved 36 teeth of patients who are diagnosed with pulp necrosis or with the periapical chronic periodontitis and require endodontic treatment and divided into two groups of 18 teeth each. The first microbiological sample was taken by placing a sterile paper point in the root canal, after endodontic access cavity preparation. All root canals are prepared by Protaper Universal rotary instruments (Maillefer Instruments SA, Ballaigues, Switzerland). In the first group, the disinfection of the root canals was made with photoactivated disinfection with FotoSan. In the second group was performed the endodontic treatment with the standard protocol of irrigation - 2.5% sodium hypochlorite solution and 17% EDTA. After that, the root canals are dried with sterile points, and a second microbiological sample is taken. Results: In all compared pairs, there was no significantly different effect regarding the number of microorganisms. Conclusions; The disinfection with NaOCl has the strongest antimicrobial effect in this study. Second place is occupied by PAD with FotoSan. We believe that the established antimicrobial effect of PAD make the method appropriate as complementary to routine endodontic treatment.

Relationship between MLSB resistance and the prevalent virulence genotypes among Bulgarian Staphylococcus aureus isolates

The aim of this study was to investigate the rate of resistance to macrolide-lincosamide-streptogramin B (MLSB) antibiotics, the mechanisms underlying this resistance and to evaluate their relationship with virulence genes profiles of 435 Bulgarian clinical isolates Staphylococcus aureus. The highest resistance was observed to penicillin (96.09%), followed by resistance to erythromycin and clindamycin (34.02 and 22.76%, respectively). Of the tested clinical strains of S. aureus, 96.09% contained the blaZ gene associated with penicillin resistance and 11.03%, the mecA gene responsible for methicillin resistance. The most prevalent were the erm genotypes associated with the presence mainly of ermA and ermC genes followed by ermB. The frequency rates of these genes, alone or in combinations were ermA 41.89%, ermB 27.70%, ermC 43.99%. The majority of Bulgarian macrolide resistant S. aureus exhibited cMLS phenotype, in 58.78% (P = 0.0036). The following virulence genotypes were present significantly more often in the macrolide resistant S. aureus isolates among the studied ones: hlg; hlg,seb; hlg,seb,sec; hlg,seb,seh; hlg,sec; hlg,sec,sei; hlg,sec,sei; hlg,sei; hlg,sei,sej; hlg,sej. This survey found correlation between the virulence profiles with a small number of genes and macrolide resistance among Bulgarian clinical S. aureus isolates, in contrast to sensitive strains, which possessed profiles predominantly with multiple genes.

Molecular emm typing of Bulgarian macrolide-resistant Streptococcus pyogenes isolates

Group A streptococcus (GAS) is a human pathogen causing a broad range of infections, linked with global morbidity and mortality. Macrolide resistance rates vary significantly in different parts of the world. Driving factors of the emergence and spread of resistant clones are not clearly understood. We investigated 102 macrolide-resistant GAS strains collected during the period 2014-2018 from various clinical specimens from Bulgarian patients. Strains were characterized by the presence of mefA/mefE, ermA, and ermB using polymerase chain reaction and sequencing for mefA/mefE. Resistant strains were studied by emm sequence typing and emm-cluster system. Most prevalent emm types among the macrolide-resistant GAS strains were emm28 (22.55%), emm12 (17.65%), and emm4 (16.66%). Almost all (87.25%) of the macrolide-resistant isolates harboring ermB were emm28. The isolates that carried ermA were predominantly emm12 (38.24%) and emm77 (38.24%), with fewer emm89 (23.53%). The isolates harbored predominantly mefE (49 isolates) and only 9 strains carried mefA. The most prevalent emm clusters among the GAS isolates were E4 (40.20%), A-C4 (17.65%), and E1 (16.66%). The study's results suggest that dissemination of specific clones in GAS population may also be the reason for the increasing macrolide-resistance rate in our country.

[Risk factors for bacterial vaginosis - a 3-year study in four medical centers]

BACKGROUND

Bacterial vaginosis (BV) is the most common infection of the lower genital tract among women of reproductive age. The purpose of this study was to determine the frequency of BV and the important etiological agent Gardnerella vaginalis in Bulgarian patients of different age groups, as well as, the risk factors forBV METHODS: One thousand five hundred and twenty-three (1523) women aged 16 to 45 years without previous antimicrobial therapy were included in this study. The methods used were: scoring of Gram staining of vaginal smear and polymerase chain reaction (PCR) assay for G. vaginalis.

RESULTS

Positive for BV according to the microscopic examination criteria were 47.80% from the 1523 tested women. In 88.87% from the positive samples G. vaginalis was detected using PCR, thus demonstrating high comparability of the both methods and the leading role of G. vaginalis. The most affected with BV is the age group of 21-25 years (33.21% of all subjects with BV). The most important detected risk factors were: smoking (more than 55% with BV), single marital status (only 15% with BV are married), more than I sexual partner (more than 36% had changed the sexual partner), early onset of sexual activity (75% of B V asocciated subjects started their sexual activity by the age 15-18 years).

CONCLUSIONS

The established early age for aquiring BV among Bulgarian women is very important and alarming sign. This is the first study on the etiological role of G. vaginalis and on the risk factors for BV in Bulgaria.

High prevalence of CTX-M-15-producing O25b-ST131 Escherichia coli clone in Bulgarian hospitals

According to the European Antimicrobial Resistance Surveillance System project results, Bulgaria has become one of the European countries with dramatically increasing rates of extended-spectrum beta-lactamase (ESBL) producers. The aim of this work was to investigate the epidemiology of ESBL-producing Escherichia coli clinical isolates in Bulgaria, collected from seven clinical centers in three towns, during two study periods: 2002-2003 and 2006-2009. For 193 ESBL-producing E. coli isolates random amplified polymorphic DNA (RAPD) analyses, phylogenetic typing, and screening for O25b-ST131 isolates were carried out. Antimicrobial susceptibility, ESBL-type and transferability of resistance determinants were analyzed. Four different ESBL-types, namely TEM-139, SHV-12, CTX-M-3, and CTX-M-15 were found. CTX-M-15 dominated, being found in 88% of the isolates. RAPD-typing revealed 35 types, among which type A dominated, comprising 65% of the isolates. Sixty-eight percent of the 193 isolates belonged to the O25b-ST131 clone, to the phylogenetic group B2, mostly showed RAPD-type A (92%) and were found in all participating hospitals. O25b-ST131 isolates predominantly produced CTX-M-15 (96%), and less SHV-12 (n=3) or TEM-139 (n=2). In conclusion, this study demonstrated for the first time the country-wide dissemination of a highly resistant B2 O25b-ST131 CTX-M-15 producing E. coli clone in Bulgaria.