Extensive Drug Resistance of Strong Biofilm-Producing Acinetobacter baumannii Strains Isolated from Infections and Colonization Hospitalized Patients in Southern Poland.

Acinetobacter baumannii (AB) is a bacterium that causes infections, particularly in immunocompromised patients. Treatment is challenging due to biofilm formation by AB strains, which hinders antibiotic effectiveness and promotes drug resistance. The aim of our study was to analyze the biofilm-producing capacity of AB isolates from various forms of infections in relation to biofilm-related genes and their drug resistance. We tested one hundred isolates for biofilm formation using the crystal violet microplate method. Drug resistance analyses were performed based on EUCAST and CLSI guidelines, and biofilm genes were detected using PCR. All tested strains were found to form biofilms, with 50% being ICU strains and 72% classified as strong biofilm producers. Among these, 87% were extensively drug-resistant (XDR) and 2% were extra-extensively drug-resistant (E-XDR). The most common gene set was bap, bfmS, csuE, and ompA, found in 57% of all isolates. Our research shows that, regardless of the form of infection, biofilm-forming strains can be expected among AB isolates. The emergence of E-XDR and XDR strains among non-ICU infections highlights the necessity for the rational use of antibiotics to stop or limit the further acquisition of drug resistance by A. baumannii.

Oral Myco- and Bacteriobiota and Yeast Infections in Mechanically Ventilated COVID-19 Patients.

Critically ill COVID-19 patients requiring mechanical ventilation in the intensive care unit are at risk of developing invasive candidiasis. In this study we aimed to (1) characterize oral cultivable mycobiota of mechanically ventilated adult COVID-19 patients in an ICU setting by sampling four distinct oral niches in two fixed time points with regards to oral health status, (2) investigate Candida spp. infections in this population, and (3) compare oral mycobiota with selected bacteriobiota strains during the observation in the ICU. We recruited 56 adult COVID-19 patients who qualified for mechanical ventilation. Patients received either standard or extended oral care procedures with tooth brushing. Oral samples were taken first within 36 h and after 7 days of intubation. Yeast-like fungi were identified by MALDI/TOF mass spectrometry. Yeast infection cases were retrospectively analyzed. Candida spp. in oral sampling was identified in 80.4% and 75.7%, C. albicans in 57.1% and 61.1%, and non-albicans Candida species in 48.2% and 47.2% patients at baseline and follow-up, respectively. There were no differences in the overall CFU counts of Candida spp. species and individual Candida species in oral samples, both at baseline and follow-up. At baseline, a higher prevalence of Candida spp. was associated with a higher identification rate of Lactobacillus spp. (64.4% vs. 27.3%, p = 0.041). At follow-up, there was a borderline lower prevalence of Candida spp. in patients with Lactobacillus spp. identified (57.1% vs. 87.0%, p = 0.057). The incidence rate of candidiasis was 5.4% and the incidence density was 3.1/1000 pds. In conclusion, non-albicans Candida species in oral samples were identified in nearly half of patients. Oral health was moderately impaired. A high incidence of yeast infections, including invasive cases, in patients hospitalized in the ICU due to COVID-19 and requiring mechanical ventilation was noted. Severe COVID-19 and disease-specific interventions within the ICU possibly played a major role promoting Candida spp. infections.

Impact of tooth brushing on oral bacteriota and health care-associated infections among ventilated COVID-19 patients: an intervention study.

BACKGROUND: Up to 48% of ventilated coronavirus disease 2019 (COVID-19) patients develop ventilator-associated pneumonia (VAP) during hospitalization in an ICU. Dysbiotic oral microbiota can colonize the lower respiratory tract and lead to VAP. It is recommended to introduce oral care strategies in the ICU to prevent VAP. In this study, we observed the impact of an oral hygienic protocol with tooth brushing on cultivable oral bacteriota, the incidence of HAI and patient safety among mechanically ventilated COVID-19 patients in an ICU setting. METHODS: In this prospective cohort study, we recruited 56 adult COVID-19 patients who qualified for mechanical ventilation. Patients were divided into 2 groups depending on the oral care procedure: standard and extended oral procedures with tooth brushing. Oral bacteriota samples were taken first within 36 h and after 7 days of intubation. Microorganisms were identified by MALDI/TOF mass spectrometry. bacterial health care-associated infection (HAI) cases were retrospectively analyzed by etiology. A PFGE study was performed for Klebsiella pneumoniae to check for clonal spreading of strains from oral bacteriota samples and HAI cases. RESULTS: We observed significant dysbiosis and a decrease in cultivable oral bacteriota diversity, with a high frequency of potentially pathogenic species, including Acinetobacter baumannii and K. pneumoniae. The HAI incidence rate was high (55.2/1000 patient-days), most commonly of K. pneumoniae and A. baumannii etiologies, which correlated with the presence of A. baumannii and K. pneumoniae in the oral samples. Strains isolated from VAP cases were the same as oral isolates in 8 cases. The procedure with tooth brushing led to less frequent identification of A. baumannii in oral samples (55.6% vs. 5.3%, p = 0.001); however, it did not decrease the incidence of HAIs. CONCLUSIONS: Dysbiotic oral bacteriota is an important source of respiratory pathogens. The introduction of tooth brushing in oral hygiene protocols in an ICU setting was effective in decreasing the extent of oral bacteriota dysbiosis; however, it did not reduce the risk of HAIs or mortality. TRIAL REGISTRATION: 1072.6120.333.2020.

Oral Microbiota-One Habitat or Diverse Niches? A Pilot Study of Sampling and Identification of Oral Bacterial and Fungal Biota in Patients with Type I Diabetes Mellitus Treated with Insulin Pump.

OBJECTIVE: The oral microbiota is a very complex and dynamic microbial ecosystem. Alterations of its balance can result in oral and systemic diseases. We aimed to characterize the microbiota in particular niches of the oral cavity in adult type 1 diabetes patients treated with continuous infusion of insulin with insulin pump (IP). In addition, we aimed to determine optimal sites of oral microbiota sampling in studies of large research groups of patients with DM I. DESIGN: In this pilot study, we sampled the buccal and soft palate mucosa, tongue, palatal and buccal dental surfaces and gingival pockets of adult DM I patients treated with IP. RESULTS: In total, 23 patients were recruited. The oral microbiota was dominated by Streptococus and Neisseria, with a low incidence of cariogenic S. mutans and Lactobacillus, as well as periodontal pathogens such as Prevotella. There were significant differences in overall CFU counts of all strains, Gram-positive, Staphylococci, Streptococci and S. oralis strains between mucosal and dental surface sites. The overall CFU counts of all strains and Gram-positive strains were higher in dental sites vs. mucosal sites (both p < 0.001). CFU counts of S. oralis were significantly higher in dental sites vs. gingival pocket sites (p = 0.013). Candida species were rare. The mucosal sites on the buccae presented lower diversity and bacterial counts. CONCLUSIONS: In the study group of adult DM I patients treated with IP, the microbiota in particular niches of the oral cavity was significantly different. Three distinct and optimally appropriate sampling sites for oral microflora were identified: buccal and palatal mucosa, dental surface and gingival pockets. The results of this study may be the basis for further studies of large groups of patients with DM I.

Cultivable oral bacteriota dysbiosis in mechanically ventilated COVID-19 patients.

Potential interactions between the SARS-CoV-2 virus and the human oral microbiota are currently investigated widely. Patients with COVID-19 requiring mechanical ventilation in an intensive care unit (ICU) setting are at high risk of developing severe complications, including ventilator-associated pneumonia, thus making oral health management important. The aim of this study was to evaluate the oral health status and assess the dysbiosis of cultivable oral bacteriota in COVID-19 patients hospitalized in an ICU with acute respiratory distress within 36 h following intubation. In this prospective cohort study, we recruited 56 adult COVID-19 patients that qualified for mechanical ventilation in the Temporary ICU for COVID-19 Patients of the University Hospital in Krakow. On admission to the ICU, oral health of patients was assessed using the modified Beck Oral Assessment Score (BOAS). Four oral habitats were sampled, namely the buccal mucosa, tongue, buccal dental surface and gingival pocket. Microorganisms were identified by MALDI/TOF mass spectrometry. The mean age of the study population was 66.5 ± 12.7 years, there were 24 (42.9%) females. All patients included in this study were intubated and ventilated in the ICU, with a corresponding high mortality rate (76.8%). On admission to ICU, 76.8% subjects scored 11-20 on the BOAS scale (median 12 [IQR 10-14]), indicating moderate or severe dysfunction of oral health. Potentially pathogenic bacteria were identified in the oral microbiota samples, including Acinetobacter baumannii, Enterococcus faecalis, Escherichia coli and Klebsiella pneumoniae in 23.2%, 39.3%, 17.9%, and 19.6% of patients, respectively. Lactobacillus spp. were present in 57.1% subjects. The mean CFU counts of all bacteria strains in dental brushes were 9.3E+5 (1.4E+6) and in gingival pockets 7.6E+5 (1.4E+6). The highest CFU counts were observed for Enterococcus spp. and, Lactobacillus spp., although these did not differ significantly from CFU counts of Streptococcus spp. and Staphylococcus spp. In this report we comprehensively characterized the oral health condition and cultivable oral bacteriota in COVID-19 patients hospitalized in an ICU with acute respiratory distress within 36 h following intubation. The oral bacteriota showed significant qualitative and quantitative dysbiosis. Hospitalization in an ICU and mechanical ventilation are important factors leading to oral dysbiosis in SARS-CoV-2 patients.

Antimicrobial Resistance of Enterobacteriaceae in Bloodstream Infections in Hospitalized Patients in Southern Poland.

Aim: The aim of this study was to highlight antimicrobial resistance among Enterobacteriaceae isolated from bloodstream infections in hospitals in southern Poland. Materials and Methods: The present study includes laboratory-confirmed secondary bloodstream infections (LC-BSIs), in the years 2015-2018, in hospitalized adult patients (≥18). Episodes of BSIs were defined according to the strictly described guidelines. Antimicrobial susceptibility testing was performed with the automated system and the disc diffusion method. Extended-spectrum ß-lactamases (ESBLs)-producing Enterobacteriaceae were detected using the double-disc synergy test. Results: Between 2015 and 2018, 356 episodes of secondary BSIs in 997 patients aged 21-96 years were documented in a prospective study, including 134 (37.6%) ESBL-producing Enterobacteriaceae. Escherichia coli was the predominant pathogen in internal medicine (37.6%) and surgery units (46.8%); in intensive care units (ICUs), Klebsiella pneumoniae was isolated more frequently (33.3%). Enterobacteriaceae were highly resistant to most antimicrobial agents. K. pneumoniae isolates had a higher level of resistance than E. coli, regardless of the unit. Conclusions: The increase in AMR and the widespread distribution of ESBL-producing Enterobacteriaceae in Polish hospitals can be related to the lack of or inappropriate antibiotic treatment.

Virulence and Drug-Resistance of Staphylococcus aureus Strains Isolated from Venous Ulcers in Polish Patients.

Infected chronic venous ulcers (VUs) represent a major health problem. We analysed the aerobic microbiome in the VUs, the virulence, and drug-resistance of Staphylococcus aureus (SA) strains. Swabs from 143 outpatients and inpatients Polish subjects were collected. SA strains were tested for drug sensitivity using a phenotyping method and for methicillin-resistant SA (MRSA) and macrolide-lincosamide-streptogramin B (MLSB) resistance using PCR. We analysed virulence genes, the genetic similarity of strains, and performed Staphylococcal cassette chromosome mec typing and Staphylococcal protein A typing. SA was isolated as a single one in 34.9% of cases, 31.5% paired with another pathogen, and 33.6% S. aureus combined with at least two other strains. The majority of SA isolates (68.5%) possessed the virulence lukE gene. Drug resistance was significantly common in hospitalised than in ambulatory patients (OR 3.8; 95%CI 1.8-7.91). MLSB (altogether in 19.6% isolates) were observed mostly in non-hospitalised patients (OR 9.1; 95%CI 1.17-71.02), while MRSA was detected in 11.9% of strains equally. Hospitalisation and patient's age group (aged > 78.0 or < 54.5 years) were significant predictors of the multi-drug resistant SA (MDR-SA). Over 30% of the infected VUs were associated with multi-species biofilms and presence of potentially highly pathogenic microorganisms. Elderly hospitalised patients with chronic venous ulcers are prone to be infected with a MDR-SA.

Healthcare-Associated Laboratory-Confirmed Bloodstream Infections-Species Diversity and Resistance Mechanisms, a Four-Year Retrospective Laboratory-Based Study in the South of Poland.

INTRODUCTION: Regardless of the country, advancements in medical care and infection prevention and control of bloodstream infections (BSIs) are an enormous burden of modern medicine. OBJECTIVES: The aim of our study was to describe the epidemiology and drug-resistance of laboratory-confirmed BSI (LC-BSIs) among adult patients of 16 hospitals in the south of Poland. PATIENTS AND METHODS: Data on 4218 LC-BSIs were collected between 2016-2019. The identification of the strains was performed using MALDI-TOF. Resistance mechanisms were investigated according to European Committee on Antimicrobial Susceptibility Testing, EUCAST recommendations. RESULTS: Blood cultures were collected from 8899 patients, and LC-BSIs were confirmed in 47.4%. The prevalence of Gram-positive bacteria was 70.9%, Gram-negative 27.8% and yeast 1.4%. The most frequently isolated genus was Staphylococcus (50% of all LC-BSIs), with a domination of coagulase-negative staphylococci, while Escherichia coli (13.7%) was the most frequent Gram-negative bacterium. Over 4 years, 108 (2.6%) bacteria were isolated only once, including species from the human microbiota as well as environmental and zoonotic microorganisms. The highest methicillin resistant Staphylococcus aureus (MRSA) prevalence was in intensive care units (ICUs) (55.6%) but S. aureus with resistance to macrolides, lincosamides and streptogramins B (MLSB) in surgery was 66.7%. The highest prevalence of E. faecalis with a high-level aminoglycoside resistance (HLAR) mechanism was in ICUs, (84.6%), while E. faecium-HLAR in surgery was 83.3%. All cocci were fully glycopeptide-sensitive. Carbapenem-resistant Gram-negative bacilli were detected only in non-fermentative bacilli group, with prevalence 70% and more. CONCLUSIONS: The BSI microbiology in Polish hospitals was similar to those reported in other studies, but the prevalence of MRSA and enterococci-HLAR was higher than expected, as was the prevalence of carbapenem-resistant non-fermentative bacilli. Modern diagnostic techniques, such as MALDI-TOF, guarantee reliable diagnosis.

Prevalence and Antimicrobial Susceptibility Profiles of Microorganisms Associated with Lower Reproductive Tract Infections in Women from Southern Poland-Retrospective Laboratory-Based Study.

OBJECTIVE: Female infections affecting the genital tract include sexually transmitted diseases, endogenous infections such as vulvovaginal candidiasis, bacterial vaginosis (BV) or aerobic vaginitis (AV) and healthcare-associated infections. The aim of the study was to analyze the etiological factors of the vaginal dysbacteriosis, and the antimicrobial susceptibility of the dominant bacterial and fungal infections in different age groups of outpatient women from the Silesian Region. MATERIALS AND METHODS: A retrospective laboratory-based multi-center study encompassed 4994 women of different ages in Silesian Voivodeship, in the south of Poland; patients who had vaginal swabs collected as per physicians' orders during the period from 1 January 2017 until 30 June 2018 were included in the study. The inclusion criteria were: non-hospitalized female, aged ≤80, with suspected vulvovaginal candidiasis or bacterial vaginosis and clinical sings of infections. RESULTS: Gram-positive cocci were the ones most often isolated: Enterococcus faecalis (29.2%) and Streptoccoccus agalactiae (13.1%), followed by bacilli from the Enterobacteriaceae group, including Escherichia coli (26.3%). The presence of Streptococcus agalactiae was confirmed in 13.1%, slightly more often in the 45-80 age group, and Gardnerella vaginalis in 6.4%, most often in women aged 15-24. The prevalence of yeast-like infections was 24.3%, Candida albicans accounted for 78.3%, whereas among C. non-albicans spp.-C. glabrata dominated (14.9%) followed by C. parapsilosis (3.8%). The highest resistance was observed only in Streptococcus agalactiae as the MLSB mechanism (Macrolide-lincosamide-streptogramin B) was identified in 38.6% of strains. The prevalence of vulvovaginal candidiasis was 24.3%, the highest in women aged 15-44. CONCLUSIONS: Drug resistance in studied vulvovaginitis was associated only with Streptococcus agalactiae. A high proportion of yeast-like aetiology was found, probably associated with recurrent infections. In the analyzed cases only the Amsel criteria and culture methods were used for diagnosis without preparations and microbiological Nugent criteria.

Antibacterial Therapy by Ag+ Ions Complexed with Titan Yellow/Congo Red and Albumin during Anticancer Therapy of Urinary Bladder Cancer.

According to the World Health Organization report, the increasing antibiotic resistance of microorganisms is one of the biggest global health problems. The percentage of bacterial strains showing multidrug resistance (MDR) to commonly used antibiotics is growing rapidly. Therefore, the search for alternative solutions to antibiotic therapy has become critical to combat this phenomenon. It is especially important as frequent and recurring infections can cause cancer. One example of this phenomenon is urinary tract infections that can contribute to the development of human urinary bladder carcinoma. This tumor is one of the most common malignant neoplasms in humans. It occurs almost three times more often in men than in women, and in terms of the number of cases, it is the fifth malignant neoplasm after prostate, lung, colon, and stomach cancer. The risk of developing the disease increases with age. Despite the improvement of its treatment methods, the current outcome in the advanced stages of this tumor is not satisfactory. Hence, there is an urgent need to introduce innovative solutions that will prove effective even in the advanced stage of the disease. In our study, a nanosystem based on ionic silver (Ag+) bound to a carrier-Titan yellow (TY) was analyzed. The possibility of binding the thus formed TY-Ag system to Congo red (CR) and albumin (BSA) was determined. TY-Ag binding to CR provides for better nanosystem solubility and enables its targeted intracellular transport and binding to immune complexes. The binding of TY-Ag or CR-TY-Ag to albumin also protects the system against the uncontrolled release of silver ions. It will also allow the delivery of silver in a targeted manner directly to the desired site in the case of intravenous administration of such a system. In this study, the MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) values of the TY-Ag or BSA-TY-Ag systems were determined in two reference strains (Escherichia coli and Staphylococcus aureus). The paper presents nanosystems with a size of about 40-50 nm, with an intense antibacterial effect obtained at concentrations of 0.019 mM. We have also discovered that TY-Ag free or complexed with BSA (with a minimal Ag+ dose of 15-20 µM) inhibited cancer cells proliferation. TY-Ag complex diminished migration and effectively inhibited the T24 cell viability and induced apoptosis. On the basis of the obtained results, it has been shown that the presented systems may have anti-inflammatory and antitumor properties at the same time. TY-Ag or BSA-TY-Ag are new potential drugs and may become in future important therapeutic compounds in human urinary bladder carcinoma treatment and/or potent antimicrobial factors as an alternative to antibiotics.

Porous poly(lactic acid) based fibres as drug carriers in active dressings.

PURPOSE: The polymeric porous surface of fibres (PLA) may influence the kinetics of release of biologically active compounds (gentamicin, G and ethacridine lactate, R) affecting development of a bacterial biofilm. METHODS: The porous fibres with different morphology were manufactured by the electrospinning method from ternary systems composed of PLA and selected solvents. Fibres morphology was examined using a scanning electron microscopy (SEM), their structure was analyzed by FT-IR ATR spectroscopy and differential scanning calorimetry (DSC). Changes in the drug release profile were measured using ICP/UV-Vis methods and the resulting bactericidal or bacteriostatic properties were tested by two-layer disk diffusion test in relation to various drug incorporation methods. RESULTS: The porous fibres can be applied to produce drug-bearing membranes. The spectroscopic studies confirmed incorporation of gentamicin into the fibres and the presence of ethacridine lactate on their surface. Bimodal fibres distribution (P3) promoted faster release of gentamicin and ethacridine lactate from P3G and P3R materials. The electrospinning process coupled with the vapor induced phase separation influenced the glass transition temperature of the porous polymer fibres. The pre/post-electrospinning modification influenced the glass transition, maximum temperature of cold crystallization and melting point of the porous membrane, compared to the neat polymer. The polylactide fibres with gentamicin showed strong bactericidal effect on Gram-positive bacteria, while fibres with ethacridine lactate were bacteriostatic. CONCLUSIONS: The obtained fibres with complex surface morphology can be used as a membrane in active dressings as they make it possible to control the release profile of the active compounds.

Epidemiology, Drug Resistance, and Virulence of Staphylococcus aureus Isolated from Ocular Infections in Polish Patients.

Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.Analysis of the epidemiology of Staphylococcus aureus (SA) ocular infections and virulence factors of the isolates with a special emphasis on their drug resistance, and the ability of biofilm formation. In a period from 2009 to 2013, 83 isolates of SA were prospectively collected and preserved in a multicenter laboratory-based study carried out in southern Poland. Epidemiological, phenotypic, and genotypic analyses were performed. The resistance and virulence genes were analyzed. Screening for the biofilm formation was provided. Among the materials derived from ocular infections from 456 patients, SA was found in 18.2% (n = 83) of cases (one SA isolate per one patient). Most infections were identified in the age group of over 65 years (OR 8.4 95%CI; 1.03-68.49). The majority of patients (73.4%) were hospitalized. Among the virulence and resistance genes, the most frequently detected were the lukE (72.2%, n = 60) and ermA (15.6%, n = 13) genes. A positive result of the CRA test (the ability of biofilm formation) was found in 66.2% (n = 55) of isolates. Among the strains under study, 6.0% (n = 5) had the methicillin-resistant Staphylococcus aureus phenotype, and 26.5% (n = 22) had the macrolide-lincosamide-streptogramin B phenotype. In 48 (57.8%) isolates the neomycin resistance was revealed. All isolates under study were sensitive to vancomycin. The population most susceptible to ocular SA infections consists of hospitalized patients aged 65 and more. The SA strains under study showed the increased ability to biofilm formation. In the strains tested, high susceptibility to chloramphenicol and fluoroquinolones was demonstrated. However, the high level of drug resistance to neomycin detected in this study among SA isolates and the blood-ocular barrier makes it difficult to treat ocular infections.

Severe infections caused by multidrug-resistant non-fermentative bacilli in southern Poland.

BACKGROUND: The impact of multidrug-resistant organisms (MDROs), including non-fermentative bacilli (NFBs), is rising and underestimated, especially in intensive care units (ICUs). The growing prevalence of multidrug resistance (MDR) and extensive drug resistance (XDR) is challenging for clinicians, as the treatment options are limited. OBJECTIVES: The purpose of this study was to analyze the extent of the epidemiological problem of multidrugresistant, extensively drug-resistant and pandrug-resistant (PDR) non-fermentative bacilli isolated from pneumonia and bloodstream infections (BSIs) in patients hospitalized in southern Poland. MATERIAL AND METHODS: This study included 253 NFBs belonging to Acinetobacter sp. (ACI), Pseudomonas sp. (PAR), and Stenotrophomonas sp. (STM). The microorganisms were identified, and susceptibility testing was performed using a semi-automatic system. The different patterns of resistance were defined as MDR, XDR, or PDR strains. Epidemiological typing of A. baumannii from ICUs was performed by repetitive polymerase chain reaction (rep-PCR). RESULTS: More than half of the strains (57.7%) were isolated within ICUs. ACI-strains came significantly more often from ICU wards. The highest prevalence of ACI and PAR was found in pneumonia, whereas STM dominated in BSIs. ACIs were more frequently resistant than other pathogens to all studied antibiotics except colistin (n = 76; 58.9%), and they belonged to the XDR category. DiversiLab demonstrated the presence of 2 dominant clones in the ACI group, both classified as European Clone 2 (EUII). CONCLUSIONS: Our results indicate serious potential therapeutic problems related to high antibiotic resistance of ACI isolates. The stratification of drug resistance (MDR/XDR/PDR) may become an important tool for the assessment of public health epidemiology and microbiological hazards at the local, national, and international level. It allows clear presentation of the issues concerning the epidemiology of highly resistant bacilli, and the exchange of information between medical staff and local representatives of public health for the implementation of effective measures to reduce drug resistance.

Antimicrobial effect of copper alloys on Acinetobacter species isolated from infections and hospital environment.

Background: An increased proportion of Gram-negative bacteria have recently been reported among etiologic agents of infection. In Poland, Acinetobacter baumannii is a big problem for hospitals, especially intensive care units. Touch surfaces made from materials with antimicrobial properties, especially copper alloys, are recommended as a supplementary method of increasing biological safety in the hospital environment. Aim of the study: The objective of this study is to determine the susceptibility to selected copper alloys of three clinical Acinetobacter baumannii strains, one Acinetobacter lwoffi and an A. pittii strain isolated from the hospital environment. Material and method: The modification of the Japanese Standard, which the ISO 22196:2011 norm was used for testing antimicrobial properties of CuZn37, CuSn6 and CuNi18Zn20 and Cu-ETP and stainless steel as positive and negative control, respectively. Results: The highest cidal efficiency, expressed as both time and the degree of reduction of the initial suspension density, against all of the tested Acinetobacter strains was found for ETP copper. But, the results of our study also confirmed effective activity (bacteriocidal or bacteriostatic) of copper alloys selected for the study, contrary to the stainless steel. The reduction in bacterial suspension density is significantly different depending on the strain and copper alloy composition. Conslusions: The results of our study confirmed the effective antibacterial activity of copper and its selected alloys against clinical Acinetobacter baumannii and Acinetobacter lwoffii strains, and Acinetobacter pittii strain isolated from the hospital environment.

Multi-locus sequence typing (MLST) of non-fermentative Gram-negative bacilli isolated from bloodstream infections in southern Poland.

Non-fermentative Gram-negative bacilli are now one of the most important causes of severe infections in Polish hospitals. Acinetobacter species are serious concern because of the high prevalence of multi-drug resistance among strains. Resistance profiles for 53 Gram-negative non-fermentative blood isolates were done. MLST was carried out using 44 strains representing the most commonly isolated species: A. baumannii, P. aeruginosa, and S. maltophilia. MLST revealed that all 22 A. baumannii belonged to sequence type (ST) 2. The P. aeruginosa isolates belonged to 10 different STs. Four S. maltophilia isolates matched STs present in the database (ST4, ST15, ST116, ST142), seven isolates showing novel sequence types. Among P. aeruginosa and S. maltophilia PFGE confirmed the genetical variety of strains.

Acinetobacter baumannii isolated from hospital-acquired infection: biofilm production and drug susceptibility.

Acinetobacter baumannii cause opportunistic nosocomial infections and is often multidrug resistant. It has ability to form biofilm. The possession of drug resistance mechanism and ability of biofilm formation seems to be the different way to enhancement of viability in stressful environment. In this study, we evaluate relation between these two factors. The biofilm formation was investigated in M63 medium with casein in microtiter plates, and the drug susceptibility was performed by disk diffusion methods. We found that 80-98% strains formed a biofilm. Strains showing sensitivity to amikacin and tobramycin from ICU produced more biofilm than strains showing resistance to these antibiotics. Ceftazidime-sensitive strains formed a smaller biofilm than resistant. The logistic regression shows association between drug resistance and strains originating from ICU. In case of ceftazidime, strong biofilm formation and descending from ICU reduced the likelihood of drug sensitivity. For other drugs such as aminoglycosides, fluoroquinolones, trimethoprim/sulfamethoxazole, and tetracycline, we found opposite relation (but it was not statistically significance). However, generally it seems that strong biofilm producers from ICUs are often more susceptible to antibiotics. This situation can be explained by the fact that bacteria protected in biofilm do not need mechanisms responsible for resistance of planktonic cells.

Antibiotic resistance, ability to form biofilm and susceptibility to copper alloys of selected staphylococcal strains isolated from touch surfaces in Polish hospital wards.

BACKGROUND: Despite the employment of sanitary regimes, contact transmission of the aetiological agents of hospital infections is still exceedingly common. The issue of microbe transmission becomes particularly important when facing multidrug-resistant microorganisms such as methicillin-resistant staphylococci. In the case of deficiencies in cleaning and disinfection procedures, hospital equipment made of copper alloys can play an important role, complementing traditional hospital hygiene procedures. The objective of this study was to characterize staphylococcal strains isolated from touch surfaces in Polish hospital wards in terms of their drug resistance, ability to form biofilm and susceptibility to antimicrobial activity of copper alloys. METHODS: The materials for the study were 95 staphylococcal strains isolated from touch surfaces in 13 different hospital wards from Malopolska province (the south of Poland). Phenotypic and genotypic antibiotic resistance were checked for erythromycin, clindamycin, gentamycin, ciprofloxacin, trimethoprim/sulfamethoxazole and mupirocin. Biofilm formation ability for the tested strains was checked with the use of culture on Congo red agar. Susceptibility to copper, tin bronze, brass and new silver was tested using a modification of the Japanese standard. RESULTS: Over 67% of the analysed staphylococcal strains were methicillin-resistant (MR). Four strains were resistant to all of the tested antibiotics, and 14 were resistant to all except mupirocin. Strains classified as MR had significantly increased resistance to the remaining antibiotic groups. About one-third of the analysed strains revealed biofilm-forming ability. Among the majority of species, biofilm-forming and non-biofilm-forming strains were distributed evenly; in the case of S. haemolyticus only, negative strains accounted for 92.8%. Susceptibility to copper alloys was different between strains and rather lower than in the case of the SA strain selected for comparison. CONCLUSIONS: Coagulase-negative staphylococci, the most commonly isolated in Polish hospital wards, should not be neglected as an infection risk factor due their high antibiotic resistance. Our experiments confirmed that touch surfaces made of copper alloys may play an important role in eliminating bacteria from the hospital environment.

Virulence and antimicrobial resistance of Staphylococcus aureus isolated from bloodstream infections and pneumonia in Southern Poland.

OBJECTIVES: Staphylococcus aureus remains the most important cause of infections in hospitals and long-term care facilities. The aim of this study was to analyse the resistance, virulence, and epidemiological and genetic relationships of S. aureus from bloodstream infections (BSIs) and pneumonia from patients in Southern Poland. METHODS: All strains were tested for antimicrobial susceptibility using the disk diffusion method. Etest was also performed for vancomycin, teicoplanin, tigecycline, oxacillin, cefoxitin and penicillin. PCR amplification was used to detect selected virulence genes. The genetic similarity of methicillin-resistant S. aureus (MRSA) isolates was determined by spa typing and pulsed-field gel electrophoresis (PFGE). Using the BURP algorithm and the Ridom SpaServer database, spa types were clustered into different clonal complexes (spa-CCs). RESULTS AND CONCLUSIONS: MRSA strains were observed at a prevalence of 26.7%, but 88.6% of hospital-acquired infections were MRSA, with no difference between BSIs and pneumonia. The highest resistance was observed to erythromycin and tobramycin. None of the strains were resistant to linezolid, glycopeptides or tigecycline. The strains had no significant virulence factors and the number of virulence genes present did not correlate with the degree of drug resistance. PFGE typing showed relatively high diversity of strains. The majority of isolates belonged to spa type t003 (CC5).

Antimicrobial Properties of Selected Copper Alloys on Staphylococcus aureus and Escherichia coli in Different Simulations of Environmental Conditions: With vs. without Organic Contamination.

Background: Hospital equipment made from copper alloys can play an important role in complementing traditional methods of disinfection. Aims of the study: The aim of this study was to assess the dynamics of the antimicrobial properties of selected copper alloys in different simulations of environmental conditions (with organic contamination vs. without organic contamination), and to test alternatives to the currently used testing methods. Materials and Methods: A modification of Japanese standard JIS Z 2801 as well as Staphylococcus aureus (SA) and Escherichia coli (EC) suspended in NaCl vs. tryptic soy broth (TSB) were used in tests performed on seven commonly used copper alloys, copper, and stainless steel. Results: A much faster reduction of the bacterial suspension was observed for the inoculum prepared in NaCl than in TSB. A faster reduction for EC than for SA was observed in the inoculum prepared in NaCl. The opposite results were found for the inoculum based on TSB. A significant correlation between the copper concentration in the copper alloys and the time and degree of bacterial suspension reduction was only observed in the case of EC. Conclusions: This study confirmed the antimicrobial properties of copper alloys, and additionally showed that Staphylococcus aureus was more resistant than Escherichia coli in the variant of the experiment without organic contamination. However, even for SA, a total reduction of the bacterial inoculum's density took no longer than 2 h. Under conditions simulating organic contamination, all of the tested alloys were shown to have bactericidal or bacteriostatic properties, which was contrary to the results from stainless steel.