Causative Agents Of Health Care-associated Infections Research Articles

Antibiotic resistance pattern of waterborne causative agents of healthcare-associated infections: A call for biofilm control in hospital water systems

BackgroundIn recent years, the global spread of antimicrobial resistance has become a concerning issue, often referred to as a “silent pandemic”. Healthcare-associated infections (HAIs) caused by antibiotic-resistant bacteria (ARB) are a recurring problem, with some originating from waterborne route. The study aimed to investigate the presence of clinically relevant opportunistic bacteria and antibiotic resistance genes (ARGs) in hospital water distribution systems (WDSs). MethodsWater and biofilm samples (n = 192) were collected from nine hospitals in Isfahan and Kashan, located in central Iran, between May 2022 and June 2023. The samples were analyzed to determine the presence and quantities of opportunistic bacteria and ARGs using cultural and molecular methods. ResultsStaphylococcus spp. were highly detected in WDS samples (90 isolates), with 33 % of them harboring mecA gene. However, the occurrences of E. coli (1 isolate), Acinetobacter baumannii (3 isolates), and Pseudomonas aeruginosa (14 isolates) were low. Moreover, several Gram-negative bacteria containing ARGs were identified in the samples, mainly belonging to Stenotrophomonas, Sphingomonas and Brevundimonas genera. Various ARGs, as well as intI1, were found in hospital WDSs (ranging from 14 % to 60 %), with higher occurrences in the biofilm samples. ConclusionOur results underscore the importance of biofilms in water taps as hotspots for the dissemination of opportunistic bacteria and ARG within hospital environments. The identification of multiple opportunistic bacteria and ARGs raises concerns about the potential exposure and acquisition of HAIs, emphasizing the need for proactive measures, particularly in controlling biofilms, to mitigate infection risks in healthcare settings.

Bacteriophage cocktail shows no toxicity and improves the survival of Galleria mellonella infected with Klebsiella spp.

Klebsiella spp. are causative agents of healthcare-associated infections in patients who are immunocompromised and use medical devices. The antibiotic resistance crisis has led to an increase in infections caused by these bacteria, which can develop into potentially life-threatening illnesses if not treated swiftly and effectively. Thus, new treatment options for Klebsiella are urgently required. Phage therapy can offer an alternative to ineffective antibiotic treatments for antibiotic-resistant bacteria infections. The aim of the present study was to produce a safe and effective phage cocktail treatment against Klebsiella pneumoniae and Klebsiella oxytoca, both in liquid in vitro culture and an in vivo Galleria mellonella infection model. The phage cocktail was significantly more effective at killing K. pneumoniae and K. oxytoca strains compared with monophage treatments. Preliminary phage cocktail safety was demonstrated through application in the in vivo G. mellonella model: where the phage cocktail induced no toxic side effects in G. mellonella. In addition, the phage cocktail significantly improved the survival of G. mellonella when administered as a prophylactic treatment, compared with controls. In conclusion, our phage cocktail was demonstrated to be safe and effective against Klebsiella spp. in the G. mellonella infection model. This provides a strong case for future treatment for Klebsiella infections, either as an alternative or adjunct to antibiotics.IMPORTANCEKlebsiella infections are a concern in individuals who are immunocompromised and are becoming increasingly difficult to treat with antibiotics due to their drug-resistant properties. Bacteriophage is one potential alternative therapy that could be used to tackle these infections. The present study describes the design of a non-toxic phage cocktail that improved the survival of Galleria mellonella infected with Klebsiella. This phage cocktail demonstrates potential for the safe and effective treatment of Klebsiella infections, as an adjunct or alternative to antibiotics.

Microbiological and molecular genetic characteristics of Klebsiella pneumoniae isolates, extracted under conditions of cardiac surgery hospital

Klebsiella pneumoniae is one of the main causative agents of healthcare-associated infections (HAI) worldwide. The study was aimed at molecular characterization of beta-lactam antibiotic resistance in K. pneumoniae isolated in the cardiac surgery hospital, identify hypervirulent isolates and assess isolate genetic relatedness. K. pneumoniae isolated from the clinical material of patients (n = 50) at cardiac surgery departments as well as anesthesiology and reanimation department treated at the cardiovascular surgery hospital in Perm from July 2021 to December 2022 were analyzed. Bacteriological studies were performed on an automatic analyzer WalkAway-96Plus (Beckman Coulter, USA). The sensitivity to thirteen antimicrobials, production of extended-spectrum beta-lactamases (ESBL) and multidrug resistance (MDR) phenotype were assessed. The string test was used to screen hypermucoviscous K. pneumoniae. Isolate relatedness (ERIC-PCR), presence of beta-lactamase genes (blaTEM, blaCTX-M, blaSHV, blaOXA, blaKPC, blaVIM-2, blaIMP-1, blaNDM-1), as well as genes associated with hypervirulence (prmpA, iucA, peg-344, wzyK2, magA) were analyzed by PCR. Amplifications were performed in a DNA Engine Dyad Thermal Cycler (Bio-Rad, USA). Gel documentation system Gel-Doc XR (Bio-Rad, USA) was used for band visualization and data documentation. According to the study results, it was found that carbapenem-resistant isolates accounted for almost 76% of all isolates, the ESBL-phenotype had 90%, and MDR-phenotype — 88% of studied isolates. According to the string test results, 8% of K. pneumoniae isolates had a hypermucoviscous phenotype. As for genes associated with hypervirulence, it was shown that the iucA gene was the most common, amplified in 54% of isolates, prmpA was detected in 38% of isolates, 48% of isolates had wzyK2 or magA genes encoding capsular type K1/K2. Almost a third of K. pneumoniae samples contained a combination of the rmpA and iucA genes, and they were isolated more often in the group of patients with active infection. Only carbapenem-sensitive microorganisms had hypermucoviscous phenotype, K1 capsular type, and a combination of prmpA, iucA, peg-344 genes, whereas the K2 capsular type was most common among carbapenem-resistant K. pneumoniae. Based on molecular genetic typing, it was found that 24% of K. pneumoniae isolates were assigned to four genome groups of identical cultures, 76% of the isolates had individual profiles. Closely related isolates were found among patients from different departments that indicates a potential pathogen circulation in the closed circuit “surgery department–department of anesthesiology” and “reanimation–surgery department”.

Healthcare-associated Staphylococcus aureus infections in children in Turkey: A six-year retrospective, single-center study

Objective: To describe clinical and epidemiological characteristics, antimicrobial susceptibility and mortality-associated factors of healthcare-associated infections (HCAIs) caused by Staphylococcus (S.) aureus in children. Methods: We conducted a retrospective, single-centre study of pediatric HCAIs caused by S. aureus from a tertiary care hospital in Turkey between February 2014 and December 2019. The clinical and epidemiological characteristics and antimicrobial susceptibility of the methicillin-susceptible and methicillin-resistant S. aureus (MSSA and MRSA) isolates was evaluated. Results: A total of 310 pediatric patients were examined. Overall, 225 (72.6%) isolates were MSSA and 85 (27.4%) were MRSA. All S. aureus isolates were susceptible to teicoplanin, vancomycin, linezolid, tigecycline, mupirocin, and daptomycin. Penicillin resistance rates were high (89.0%), while fosfomycin, gentamicin, and clindamycin resistance rates were low (1.3%, 1.0%, and 2.3%, respectively). Except susceptibility to fosfomycin, which was significantly lower in 2014 compared to 2018 and 2019, no significant difference was found in the antimicrobial susceptibility of S. aureus isolates between the years. Baseline characteristics and mortality rate were similar comparing MRSA and MSSA causing HCAIs. The mortality rate of HCAIs caused by S. aureus was 6.5% (20 patients). Malignancy was an independent risk factor associated with mortality in the multivariate analysis (OR 5.446, 95% CI 1.573-18.849). Conclusions: Our findings demonstrate that MSSA remained the most causative agent of HCAIs caused by S. aureus. The mortality rate was 6.5%, the antibiotic resistance rate was quite high for penicillin and diagnosis of malignancy was the main risk factor for increasing mortality in children. These findings could help improve the management of HCAIs caused by S. aureus in children.

Vancomycin-resistant enterococci isolated in tertiary care in Southern Thailand: Prevalence and characterization of biofilm formation

Abstract Introduction Vancomycin-resistant enterococci (VRE) are important causative agents of healthcare-associated infections. This study investigated the prevalence of VRE isolates of clinical specimens from a tertiary hospital in Southern Thailand and their biofilm formation and associated virulence factors. Methods This retrospective study was conducted from February 2011 to March 2021 at a 1,000-bed tertiary care hospital in Songkhla Province in Southern Thailand. Results In total, 95 VRE isolates were collected. Urine had the highest VRE prevalence (38%), followed by pus or secretions (23%) and the digestive tract (19%). VRE infections were most common in medical (45%) and surgical wards (19%). VRE strains were equally resistant (85–100%) to the six classes of antibiotics commonly used in a tertiary care hospital. Biofilms were produced by 73% of the multidrug-resistant strains; however, 93% of VRE isolates lacking hyl were highly capable of producing biofilms. Conclusions No relationship was observed between virulence genes and biofilm formation. Thus, efforts to establish appropriate treatment and control measures are necessary, as distinctive VRE characteristics are relevant to the treatment of enterococcal infections in hospitals.

How Does Hospital Microbiota Contribute to Healthcare-Associated Infections?

Healthcare-associated infections (HAIs) are still a global public health concern, associated with high mortality and increased by the phenomenon of antimicrobial resistance. Causative agents of HAIs are commonly found in the hospital environment and are monitored in epidemiological surveillance programs; however, the hospital environment is a potential reservoir for pathogenic microbial strains where microorganisms may persist on medical equipment surfaces, on the environment surrounding patients, and on corporal surfaces of patients and healthcare workers (HCWs). The characterization of hospital microbiota may provide knowledge regarding the relatedness between commensal and pathogenic microorganisms, their role in HAIs development, and the environmental conditions that favor its proliferation. This information may contribute to the effective control of the dissemination of pathogens and to improve infection control programs. In this review, we describe evidence of the contribution of hospital microbiota to HAI development and the role of environmental factors, antimicrobial resistance, and virulence factors of the microbial community in persistence on hospital surfaces.

Whole genome sequencing of <i>Acinetobacter baumannii</i> strains isolated from hospital patients in the northern territories of the Tyumen region

Introduction. is to The analysis of the genetic relatedness of isolates aiming to find the source of infection is an important task of nosocomial infection control. The most common causative agent of healthcare-associated infections is Acinetobacter baumannii.Objective. To evaluate the results of whole genome sequencing of A. baumannii bacteria isolated from clinical samples of patients undergoing inpatient treatment in the northern territories of the Tyumen region.Materials and methods. Nine isolates of A. baumannii from the clinical material of patients were studied. Bacterial cultures were identified by mass spectrometry. Whole genome sequencing, multilocus sequence typing and search for markers of antibiotic resistance were performed.Results. The studied strains belonged to sequence types ST2 and ST187, and to the international clonal complex CC2. All A. baumannii isolates were found to have beta-lactamase genes, as well as genes for resistance to aminoglycosides, to the MLS group of antibiotics, and to tetracyclines. The presence of a cluster of genes associated with virulence was detected: those responsible for the synthesis of acinetobactin and iron binding, surface antigen 1 and porin.Conclusion. Based on data of a single nucleotide polymorphism (SNP) analysis, A. baumannii isolates from the clinical material of patients of healthcare institution #1 belong mainly to one bacterial strain. Isolates of A. baumannii from the clinical material of patients of healthcare institution #2 are closely related. The ability to distinguish clinical isolates of A. baumannii at the level of several SNPs per genome will improve the identification of the source of infection, and whole genome sequencing data can contribute to the rational prescription of antibiotic therapy and the correction of disinfection and antiseptic measures.

From Copper Tolerance to Resistance in Pseudomonas aeruginosa towards Patho-Adaptation and Hospital Success.

The hospital environment constitutes a reservoir of opportunistic pathogens responsible for healthcare-associated infections (HCAI) such as Pseudomonas aeruginosa (Pa). Pa persistence within technological niches, the increasing emergence of epidemic high-risk clones in HCAI, the epidemiological link between plumbing strains and clinical strains, make it a major nosocomial pathogen. Therefore, understanding the mechanisms of Pa adaptation to hospital water systems would be useful in preventing HCAI. This review deciphers how copper resistance contributes to Pa adaptation and persistence in a hospital environment, especially within copper water systems, and ultimately to its success as a causative agent of HCAI. Numerous factors are involved in copper homeostasis in Pa, among which active efflux conferring copper tolerance, and copper-binding proteins regulating the copper compartmentalization between periplasm and cytoplasm. The functional harmony of copper homeostasis is regulated by several transcriptional regulators. The genomic island GI-7 appeared as especially responsible for the copper resistance in Pa. Mechanisms of copper and antibiotic cross-resistance and co-resistance are also identified, with potential co-regulation processes between them. Finally, copper resistance of Pa confers selective advantages in colonizing and persisting in hospital environments but also appears as an asset at the host/pathogen interface that helps in HCAI occurrence.

A 12-year epidemiological study of Acinetobacter baumannii from blood culture isolates in a single tertiary-care hospital using polymerase chain reaction (PCR)-based open reading frame typing.

Acinetobacter baumannii is a causative agent of healthcare-associated infections, and the introduction and spread of A. baumannii that has acquired drug resistance within a hospital are serious healthcare problems. We investigated the transition of epidemic clones and the occurrence of outbreaks by molecular epidemiological analysis to understand the long-term behavior of A. baumannii within a single facility. A. baumannii isolates collected from blood-culture-positive patients between January 2009 and December 2020 were subjected to PCR-based open reading frame typing (POT) for species identification, clonal typing, and homology searches. Of the strains isolated from blood cultures, 49 were identified as A. baumannii and analyzed with POT. The POT#1=122 clones had different antimicrobial resistance profiles to the other POT clones, and strains belonging to this clone were dominant during outbreaks of multidrug-resistant Acinetobacter. Although the clonal diversity of A. baumannii decreased and its antimicrobial resistance increased during the outbreaks, clonal diversity and the in-hospital antibiogram improved at the end of the outbreaks. The POT#1=122 clone was not eliminated from the hospital during the study period. POT is a simple and suitable method for molecular epidemiological monitoring and can show the introduction, outbreak, and subsequent transition of an epidemic clone of A. baumannii.

A case report of community-acquired Raoultella ornithinolytica infection in a healthy, young individual

BackgroundRaoultella ornithinolytica is a Gram-negative bacillus that resembles Klebsiella. This bacterium is present in many soil and aquatic environments and is a major causative agent of healthcare-associated infections (HAIs) in medical staff. Clinically, it has been reported to contribute to nosocomial infections in patients that include but are not limited to gastrointestinal, skin, and genitourinary tract infections. These complications are most common in hospitalized patients with underlying immunodeficiency, multiple comorbidities, or those receiving invasive surgery.Case presentationWe present a case of a 25-year-old patient with a R. ornithinolytica infection. The patient had no history of any disease. Her main complaints were high fever, a scattered maculopapular rash, and superficial lymph node enlargement (SLNE). Peripheral blood samples were collected for high-throughput sequencing analysis to identify pathogenic microorganisms. The results confirmed a R. ornithinolytica infection, which was treated successfully using meropenem. Loratadine was also administered to treat the patient’s compromised skin condition caused by an allergic reaction.ConclusionsTo our knowledge, this is the first case of a systemic maculopapular rash and superficial lymphadenopathy caused by a R. ornithinolytica infection acquired at the community level. Based on this case, we recommend a combination of antibiotic and antiallergic drugs to treat a R. ornithinolytica infection and associated allergic reaction to the bacteria.

ACTIVITY RANGE OF COMMERCIAL PHAGE PREPARATIONS AGAINST METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS ISOLATES

Methicillin-resistant Staphylococcus aureus (MRSA) was first discovered in 1962, since then it has been recognized as a major causative agent of healthcare-associated infections. MRSA infections are usually divided into three groups: hospital- (HA), community- (CA) and livestock-associated (LA) MRSA. The incidence of LA-MRSA infections among livestock and companion animals is a great concern because these sources could potentially be reservoirs for zoonotic infections. In Ukraine, recent statistics indicated approximately 82 % of tested livestock were S. aureus positive with 53.8 % of resistance. In addition, the diversity of MRSA in Ukraine has not been investigated.
 Antibiotic resistance during treatment in both clinical practice and veterinary medicine remains a challenge and requires alternative solutions. Bacteriophage-based treatment represents a promising biocontrol strategy with proven effectiveness against MRSA. The purpose of our research was to evaluate the activity of two commercial phage preparations against a local collection of LA-MRSA host strains and to characterize and adapt individual phages isolated from these preparations with the desired goal of enhancing their efficacy.
 In our study, we tested two commercial phage preparations (Eliava BioProduction, Georgia) Staphylococcus Bacteriophage and Intesti Bacteriophage on local LA-MRSA isolates. In addition, we utilized two single phages we isolated from these preparations. Both commercial phage preparations showed variable activity against the tested isolates. Intesti Bacteriophage cocktail lysed 60 % of isolates, whereas the single phage isolated from it was found to be ineffective. Staphylococcus Bacteriophage preparation showed activity against 30 % of MRSA tested, while the isolated phage was active against 70 % of the tested isolates. For the first time in Ukraine, in this study we assessed host range of commercial phages on local circulating livestock-associated MRSA. Further host range analysis on an expanded collection of Ukrainian MRSA isolates as well as taxonomic and genomic characterization of the phages is planned.

Strategy and Control of Antimicrobial Therapy Program Implementation at the B.V. Petrovsky National Research Center of Surgery

The introduction of local programs for the rational use of antibiotics in a multidisciplinary hospital is aimed at reducing the level of antibiotic resistance and the frequency of healthcare associated infections (HAI). The aim of the study was to analyze the frequency of infectious complications caused by pathogens with multidrug resistance and the level of resistance at the B.V. Petrovsky National Research Center of Surgery based on the implementation of the SCAT program. Material and methods. A retrospective analysis of the SCAT program implementation results on the basis of the B.V. Petrovsky National Research Center of Surgery was carried out. 1850 case histories of the surgical profile for 2018 were analyzed (male —1095, average age 56.2±14.9 years; female — 755, average age 53.7±11.9 years) and 1502 case histories for the January–October period for 2019 (male — 1114, average age 58.3±12.1 years, and female — 388, average age 55.4±12.6 years). Results. The incidence of HAI in 2018 and 2019 was 354 and 159 cases, respectively. Of these, the incidence of nosocomial pneumonia (NP) was 64 cases (61.5%) and 40 cases (38.5%); skin and soft tissue infection (SSTI) — 93 cases (57.4%) and 69 cases (42.6%); surgical site infections (SSI) — 69 cases (82.1%) and 15 cases (17.9%) in 2018 and 2019, respectively. The drug resistance index (DRI) for the most clinically significant strains of the causative agents of HAI was: Klebsiella pneumoniae — 0.14, Acinetobacter baumannii — 0.22, Klebsiella spp. — 0.11, Enterobacter cloacae — 0.15, Enterococcus faecalis — 0.18, Enterococcus faecium — 0.21. Conclusion. The proposed measures for the implementation of the SCAT program at the level of a medical organization reduce the incidence of HAI and the local level of the drug resistance index.

The possibility of using bacteria Bacillus in the production of disinfectants

Introduction. In recent years, healthcare-associated infections (HAIs) cause ever greater economic and social damage. Microorganisms circulating in medical institutions the causative agents of HAIs, become resistant to most antibiotics and many disinfectants. There is a need to create alternative mechanisms for controlling microorganisms. The purpose of the work is to determine the antagonistic activity of bacteria strains of the genus Bacillus in relation to test microorganisms, as a potential basis for the development of domestic detergents and disinfectants based on probiotics. Material and methods. The strains of Bacillus subtilis 2/10 VKPM B-2896; Bacillus subtilis VKPM B-1283; Bacillus licheniformis VKPM B-5397; Bacillus amyloliquefaciens VKPM B-5462 werethe main object of study. At the first stage of the studies, the antagonistic activity of the strains was studied by the well method, at the second stage of the studies, the antagonistic activity was studied at the test object, and at the third stage of the studies, the effectiveness of the composition containing B. subtilis VKPM B-1283, B.licheniformis VKPM B-5397 and sulfonol strains was studied. Results. As a result of studies, the antagonistic effect of bacilli against test microorganisms was revealed. When surfaces are contaminated with test microorganisms (S.aureus ATCC 6538-P, E.coli ATCC 10531, C. albicans ATCC 10231) and subsequent application of Bacillus spores, a significant reduction in the seeding rate with test microorganisms is observed after 24 hours by 97.07-100%. The use of B.subtilis VKPM B-1283 and B.licheniformis VKPM B-5397 spores together with a detergent component for treating surfaces contaminated with test microorganisms (S.aureus ATCC 6538-P, E.coli ATCC 10531, C.albicans ATCC 10231) provides a reduction in microbial seeding after 4 hours by 99.97 %. Conclusions. B.subtilis 2/10 VKPM B-2896, B.subtilis VKPM B-1283 and B.licheniformis VKPM B-5397 are promising for the use as probiotics, as the basis of detergents and disinfectants.

The possibility of using bacteria Bacillus in the production of disinfectants

Introduction. In recent years, healthcare-associated infections (HAIs) cause ever greater economic and social damage. Microorganisms circulating in medical institutions the causative agents of HAIs, become resistant to most antibiotics and many disinfectants. There is a need to create alternative mechanisms for controlling microorganisms. The purpose of the work is to determine the antagonistic activity of bacteria strains of the genus Bacillus in relation to test microorganisms, as a potential basis for the development of domestic detergents and disinfectants based on probiotics. Material and methods. The strains of Bacillus subtilis 2/10 VKPM B-2896; Bacillus subtilis VKPM B-1283; Bacillus licheniformis VKPM B-5397; Bacillus amyloliquefaciens VKPM B-5462 werethe main object of study. At the first stage of the studies, the antagonistic activity of the strains was studied by the well method, at the second stage of the studies, the antagonistic activity was studied at the test object, and at the third stage of the studies, the effectiveness of the composition containing B. subtilis VKPM B-1283, B.licheniformis VKPM B-5397 and sulfonol strains was studied. Results. As a result of studies, the antagonistic effect of bacilli against test microorganisms was revealed. When surfaces are contaminated with test microorganisms (S.aureus ATCC 6538-P, E.coli ATCC 10531, C. albicans ATCC 10231) and subsequent application of Bacillus spores, a significant reduction in the seeding rate with test microorganisms is observed after 24 hours by 97.07-100%. The use of B.subtilis VKPM B-1283 and B.licheniformis VKPM B-5397 spores together with a detergent component for treating surfaces contaminated with test microorganisms (S.aureus ATCC 6538-P, E.coli ATCC 10531, C.albicans ATCC 10231) provides a reduction in microbial seeding after 4 hours by 99.97 %. Conclusions. B.subtilis 2/10 VKPM B-2896, B.subtilis VKPM B-1283 and B.licheniformis VKPM B-5397 are promising for the use as probiotics, as the basis of detergents and disinfectants.

Grzyby jako czynniki etiologiczne wybranych zakażeń szpitalnych

Grzyby jako czynniki etiologiczne wybranych zakażeń szpitalnych

Properties of a high rate of MRSA colonization in the nasal cavity of intensive care unit doctors

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a major causative agent of healthcare-associated infections. Aims: To survey S. aureus/MRSA colonization in the nasopharyngeal cavities of intensive care unit (ICU) doctors at a university hospital. Methods: Surveys on nasopharyngeal S. aureus/MRSA colonization in 29 ICU doctors at a university hospital were conducted during July 2011 and January 2012. Polymerase chain reaction (PCR) analysis revealed mecA-positive strains as MRSA. The antimicrobial susceptibilities and toxin gene profiles of the isolates were additionally examined. Results: A total of 52% of the doctors examined during the first survey and 64% during the second survey showed S. aureus colonization, and 81% of the isolates were confirmed to be MRSA. Most of the MRSA strains had partially mutated mecA, as determined by PCR. The MRSA isolates, except for three, were susceptible to oxacillin, suggesting that these isolates could be misidentified as methicillin-sensitive S. aureus (MSSA) in hospital laboratories, whereas several resistant colonies appeared after an additional 3 days of incubation in the presence of oxacillin. Among the MRSA isolates, only four were tst-positive, and none were eta/etb-positive. Conclusion: A high rate of MRSA colonization in the nasal cavity of ICU doctors at a university hospital was observed. Most MRSA isolates, as determined through mecA detection, were susceptible to oxacillin, but produced resistant mutants in the presence of oxacillin. Therefore, we strongly suggest monitoring and/or eradication of colonized MRSA in the nasal cavity of ICU doctors.

White Light-Activated Antimicrobial Paint using Crystal Violet.

Crystal violet (CV) was incorporated into acrylic latex to produce white-light-activated antimicrobial paint (WLAAP). Measurement of the water contact angle of the WLAAP showed that the water contact angle increased with increasing CV concentration. In a leaching test over 120 h, the amount of CV that leached from the WLAAPs was close to the detection limit (<0.03%). The WLAAPs were used to coat samples of polyurethane, and these showed bactericidal activity against Escherichia coli, which is a key causative agent of healthcare-associated infections (HAIs). A reduction in the numbers of viable bacteria was observed on the painted coated polyurethane after 6 h in the dark, and the bactericidal activity increased with increasing CV concentration (P < 0.1). After 6 h of white light exposure, all of coated polyurethanes demonstrated a potent photobactericidal activity, and it was statistically confirmed that the WLAAP showed better activity in white light than in the dark (P < 0.05). At the highest CV concentration, the numbers of viable bacteria fell below the detection limit (<10(3) CFU/mL) after 6 h of white light exposure. The difference in antimicrobial activity between the materials in the light and dark was 0.48 log at CV 250 ppm, and it increased by 0.43 log at each increment of CV 250 ppm. The difference was the highest (>1.8 log) at the highest CV concentration (1000 ppm). These WLAAPs are promising candidates for use in healthcare facilities to reduce HAIs.

Anaerobes in biofilm-based healthcare-associated infections.

Anaerobic bacteria can cause an infection when they encounter a permissive environment within the host. These opportunistic pathogens are seldom recovered as single isolates but more frequently are involved in polymicrobial infections, together with other anaerobes or aerobes. Nowadays it's known that some anaerobic bacteria are also able to grow as biofilm even if this feature and its role in the healthcare-associated infections (HAIs) are still poorly characterized. As consequence, the involvement of biofilm-forming anaerobic bacteria in infections related to healthcare procedures, including surgery and medical devices implantation, is underestimated.The current knowledge on the role of biofilm-growing anaerobes in HAIs has been here reviewed, with particular reference to respiratory, intestinal, intra-abdominal, wound, and urogenital tract infections. Even if the data are still scarce, the ability to form biofilm of opportunistic anaerobic species and their possible role as causative agents of HAIs should alert even more clinicians and microbiologists on the need to search for anaerobes in clinical samples when their presence can be reasonably assumed.

P089: Surveillance of bacterial resistance to disinfectants

The causative agents of healthcare-associated infections are known to be resistant both to antibiotics, disinfectants, and antiseptics. Our sampling researches allowed to implement a monitoring in hospitals.

P249: Serratia marcescens among neonates

Healthcare-associated infections (HAIs) remain a permanent challenge among neonates. Serratia marcescens (SM) is a rare causative agent of HAIs, responsible for not more than 2% of HAI cases.