Epidemiological Characteristics of Shiga Toxin-Producing Escherichia coli Responsible for Infections in the Polish Pediatric Population.

Shiga toxin-producing Escherichia coli (STEC) are zoonotic pathogens causing hemorrhagic colitis and hemolytic uremic syndrome (HUS) in children and the elderly. Stool samples were collected from 180 children hospitalized in five pediatric centers in Poland in 2018-2022. Direct stx1/stx2 gene detection by PCR in feces and E. coli isolates was performed. Antibiotic susceptibility was tested according to EUCAST v.12. Randomly selected isolates were serotyped with O157 antiserum and genotyped by pulsed-field gel electrophoresis (PFGE). A total of 44 E. coli isolates were confirmed as STEC by PCR. Among them, 84.4% were positive for stx2, and equally 6,8% for only stx1 and both stx1 and stx2 genes. The stx1 gene was also found in one Citrobacter freundii isolate. E. coli serotype O157 was present in 97.6% of the isolates. STEC infections most often occurred between June-October with a peak in July and August (51%). The highest, 77.8% of STEC isolates were found in the 1-5 years old group. No extended-spectrum ß-lactamases (ESBL) were found. Resistance only to amoxicillin/clavulanic acid (24.4%), piperacillin/tazobactam (3%), cefotaxime (6%), gentamicin (6%), ciprofloxacin (3%), azithromycin (3%), trimethoprim/sulfamethoxazole (24,2%) was detected. PFGE analysis showed 18 PFGE types with no clonal distribution. Eight isolates with A, B, and C PFGE types showed genetic relatedness in the type with no detection of transmission way of distribution. STEC strains pose a serious threat to human health, therefore demographic and epidemiological characteristics are crucial for their surveillance.

Identification of human-dependent routes of pathogen's transmission in a tertiary care hospital.

OBJECTIVES: The purpose of the study was to validate the risk of patients' exposure to pathogenic flora carried on hands of students, visitors, and patients themselves, analyzing its density and genera and to compare them with the microflora of healthcare workers (HCWs). PATIENTS AND METHODS: Between May and June 2018, five groups of participants were included. Each group consisted of eight individuals. Palmar skin imprints were obtained from dominant hands of doctors, nurses, students, visitors, and patients in orthopedics ward. Imprints were incubated at 37°C under aerobic conditions, and colony-forming units (CFU) on each plate were counted after 24, 48, and 72 h. Microorganisms were identified. RESULTS: Hands of doctors were colonized more often by Gram - positive non-spore-forming rods bacteria than hands of nurses (p<0.05). A higher number of Staphylococcus epidermidis CFUs was observed on doctors' than on nurses' hands (p<0.05), whereas Staphylococcus hominis was isolated from doctor's and patients' imprints, but was not from nurses' and students' imprints (p<0.05). Micrococcus luteus colonized patients' hands more often than students' (p<0.05), visitors' hands than doctors' (p<0.05), students' than nurses' (p<0.05), visitors' than nurses' (p<0.05) and patients' hands (p<0.05). Staphylococcus aureus (S. aureus) was isolated only from one doctor and one nurse (203 and 10 CFUs/25 cm2 ). Imprints taken from the hands of patients, students and visitors were S. aureus-free. No methicillin-resistant S. aureus (MRSA), vancomycin-resistant enterococci, nor expanded spectrum betalactamase-positive or carbapenemase-positive rods were isolated. The number of Gram-negative rods was the highest on visitors' hands, significantly differing from the number on patient's, doctor's, nurse's, and student's hands. Spore-forming rods from genus of Bacillus were isolated from representatives of all tested groups. Bacillus cereus occurred more commonly on visitors' hands than doctors' hands (p<0.05). CONCLUSION: Patients, students, and visitors may play the causal role in the spread of pathogenic bacteria, particularly spore-forming rods. Our study results confirm the effectiveness of educational activities, that is the hospital's hand hygiene program among HCWs, patients, and visitors. Hand hygiene procedures should be reviewed to put much more effort into reducing the impact of all studied groups on the transmission of infectious diseases.

An Analysis of Resistance Patterns of Oral Streptococci Obtained from Orofacial Infections Against Beta-lactams, Clindamycin and Vancomycin over 2014-2018.

PURPOSE: Comparison of viridans group Streptococcus (VGS) susceptibility to benzylpenicillin, ampicillin, clindamycin and vancomycin in order to determine resistance rates to assess whether guidelines for prophylactic or therapeutic antibiotic treatment include the present resistance patterns. MATERIALS AND METHODS: A retrospective analysis of antimicrobial susceptibility testing (AST) over 4 consecutive years (2014-2017) and 4 months in 2018 for 779 VGS isolates (cumulative data). Isolates originated from pus from orofacial infections cases and tissue fragments from patients undergoing maxillofacial surgeries Results: The highest resistance rate was observed to clindamycin. The highest overall resistance rate was for Streptococcus parasanguinis 43% and S. constellatus 49%; the lowest was for S. anginosus 12%. All S. anginosus isolates were susceptible to ampicillin during tested period. All isolates of analysed species were susceptible to vancomycin through studied period. CONCLUSION: Due to high resistance levels, individual antibiotic susceptibility testing for strains should become mandatory.

Corynebacterium coyleae as potential urinary tract pathogen.

Corynebacterium coyleae is part of the commensal microflora of the skin, urethra, mucous membranes, and genital tract. Isolates from patients with urinary tract infection (UTI) were reported, but the pathogenic potential of this species has not been defined yet. The aim of the study is to determine whether C. coyleae could be the etiological agent of UTI and to analyze its antibiotic susceptibility. Urine samples were cultured quantitatively according to accepted laboratory procedures. The identification of bacterial isolates was carried out using the Vitek MS (bioMérieux) and antibiotic susceptibility was tested using disc diffusion according to EUCAST guidelines. Between 1 January 2017 and 30 October 2018, a total of 39 C. coyleae strains were isolated. This represented 0.32% of all urine samples cultured in the laboratory during the collection period. The strains were isolated from samples obtained from 35 women and 3 men (age median for all-64 years). One female patient presented with C. coyleae in her urine twice at an interval of 21 months. In six cases of UTI, C. coyleae was isolated in monoculture. The isolates had the same resistance pattern. A total of 11 strains were obtained from cases with a clinical diagnosis of UTI. In 13 cases, the strain was cultured in a monoculture and in 28 cases with accompanying species. All strains were susceptible to vancomycin. However, resistance to ciprofloxacin was observed for 58.4% of the strains. Urine isolates of C. coyleae must be considered as contamination or normal flora in most cases (28/39, 72%). In the remaining cases, it can be considered as potential etiologic agents, mostly in women and especially in the 6 UTI cases where C. coyleae was found as the single culture-positive species. Several of these isolates demonstrate resistance to antibiotics commonly used in empiric treatment of urinary tract infections.

Erythromycin or Clindamycin - is it Still an Empirical Therapy against Streptococcus agalactiae in Patients Allergic to Penicillin?

Retrospective analysis of Streptococcus agalactiae antibiotic susceptibility isolated in 2010-2013 was performed. Penicillin was still the first-line antibiotic. Due to the high percentage of strains resistant to erythromycin and clindamycin empirical treatment with these antibiotics may not be effective. Lower resistance rate to erythromycin and clindamycin among strains isolated from infected pregnant women and newborns were observed than among strains isolated from samples from patients hospitalized in other departments (29% and 47% v. 46% and 63%). The increasing resistance rate might give a rise to a new epidemiological situation.

Antimicrobial activity of ozonated water.

BACKGROUND: The purpose of this study was to analyze basic bactericidal and fungicidal activity of ozonated water according to EN 1040 "Chemical disinfectants and antiseptics--Quantitative suspension test for the evaluation of basic bactericidal activity of chemical disinfectants and antiseptics" and EN 1275 "Chemical disinfectants and antiseptics--Quantitative suspension test for the evaluation of basic fungicidal or basic yeasticidal activity of chemical disinfectants and antiseptics" with additional clinical multidrug-resistant bacterial strains and evaluate whether the ozonated water acts as a rapid and efficient antimicrobial agent and as such could be applied during intraoperative ozone treatment for tissue protection against infection with pathogenic bacteria. MATERIAL/METHODS: A prototype device for intraoperative ozone therapy was used. Besides standard bacterial and fungal strains, 60 clinical bacterial isolates were analyzed. RESULTS: The ozone concentration in ozonated water was sufficient to kill almost all cells of the bacterial and yeast strains tested after 30 seconds. Effective action against Aspergillus brasiliensis spores required a longer time than those required in the case of bacterial cells or vegetative cells of yeast. CONCLUSIONS: The prototype device used in our study produced high ozone concentrations in freshly prepared ozonated water. This liquid complied with the requirements of the EN Standards: basic bactericidal and basic yeasticidal activities.