Bacterial contamination of medical devices in a Greek emergency department: impact of physicians' cleaning habits

Stethoscopes or Maybe "Bacterioscopes" - Is hand Hygiene Solely Capable of Preventing Hospital-Associated Infections?

The stethoscope remains an indispensable diagnostic tool for medical students. Improper stethoscope hygiene may cause bacterial infections, including hospital-associated infections (HAIs), which challenge the Polish medical system. The study's main objective was to evaluate the hygiene habits declared by medical students. Moreover, microbiological control with the characteristics of potentially pathogenic microorganisms was performed. The study included 66 medical students from the Faculty of Medicine at the Jagiellonian University Medical College in Cracow, Poland. The participants filled in an anonymous questionnaire. Stethoscope contamination was assessed through isolation, identification, testing of antibiotic resistance, and clonality of the isolates bacterial pathogens. The survey showed that only 30.3% of students cleaned their stethoscopes after each patient, and 1.5% never did this. Of the 66 stethoscopes tested, 100% were positive for bacterial growth. Staphylococcus spp. was the most frequently isolated contaminant (50.5%). The questionnaire results demonstrated the necessity of the validated procedures for cleaning the stethoscopes. Stethoscopes used by medical students are contaminated with numerous bacterial species, including multidrug-resistant organisms. The clonal structure of the MRSA and MRSE populations acquired from stethoscopes has been demonstrated. Our results confirm the possibility that these medical devices mediate the spread of hazardous pathogens in the hospital environment. Practical exercises are essential to forming the correct hygiene habits involving stethoscopes, which enable practicing and checking the correctness of the established skills.

A quasi-experimental study on stethoscopes contamination with multidrug-resistant bacteria: Its role as a vehicle of transmission

Stethoscopes have been suggested to be a possible vector of contact transmission. However, only a few studies have focused on the prevalence of contamination by multidrug-resistant (MDR) bacteria and effectiveness of disinfection training to reduce. This study is to investigate the burden of stethoscope contamination with nosocomial pathogens and multidrug-resistant (MDR) bacteria and to analyze habit changes in disinfection of stethoscopes among healthcare workers (HCWs) before and after education and training. We performed a prospective pre and post quasi-experimental study. A total of 100 HCWs (55 doctors and 45 nurses) were recruited. HCWs were surveyed on their disinfection behavior and stethoscopes were cultured by pressing the diaphragm directly onto a blood agar plate before and after education on disinfection. Pulsed-field gel electrophoresis was performed to determine the relatedness of carbapenem-resistant Enterobacteriaceae. Most of the stethoscopes were contaminated with microorganisms before and after the intervention (97.9% and 91.5%, respectively). The contamination rate of stethoscopes with nosocomial pathogens before and after education was 20.8% and 19.2%, respectively. Stethoscope disinfection habits improved (55.1% vs 31.0%; p<0.001), and the overall bacterial loads of contamination were reduced (median colony-forming units, 15 vs 10; p = 0.019) after the intervention. However, the contamination rate by nosocomial pathogens and MDR bacteria did not decrease significantly. A carbapenemase-producing Klebsiella pneumoniae isolates from a stethoscope was closely related to isolates from the patients admitted at the same ward where the stethoscope was used. Stethoscopes were contaminated with various nosocomial pathogens including MDR bacteria and might act as a vehicle of MDR bacteria. Continuous, consistent education and training should be provided to HCWs using multifaceted approach to reduce the nosocomial transmission via stethoscopes.

Identification and resistance profile of bacteria isolated on stethoscopes by health care professionals: Systematic review

BACKGROUND

Evaluate the presence of bacteria and resistance profile in stethoscopes used by health care professionals and its consequences within the hospital environment.

METHODS

It is a systematic review, in which articles indexed in the BVS, CAPES-Periódicos, Cochrane Library, PubMed, Scientific Electronic Library Online, and ScienceDirect databases were searched.

RESULTS

Twenty-two articles were selected for this study. The significant majority of professionals does not perform hygiene of the stethoscope, either due to the lack of instructions or the lack of knowledge about the contamination's risks. In addition, over these 22 articles evaluated, only 10 demonstrated that more than 50% of the analyzed samples were contaminated with some type of bacteria. Coagulase-negative Staphylococcus spp., Staphylococcus aureus, Acinetobacter spp., Pseudomonas spp., and Klebsiella pneumoniae were the most recurrent pathogens. Besides that, multiresistant strains were also isolated, highlighting resistance to Ampicillin and Clindamycin.

CONCLUSIONS

Indeed, the stethoscope is a potential disseminator of bacterial infections. The contamination is explained by the possible cross reactions that make the transmission of infectious agents possible. Cleaning before and after each auscultate is an efficient alternative to minimize these pathogens.

Effects of Electrokinetic Phenomena on Bacterial Deposition Monitored by Quartz Crystal Microbalance with Dissipation Monitoring

Bacterial deposition is the first step in the formation of microbial biofilms in environmental technology, and there is high interest in controlling such deposition. Earlier work indicated that direct current (DC) electric fields could influence bacterial deposition in percolation columns. Here, a time-resolved quartz crystal microbalance with dissipation monitoring (QCM-D) and microscopy-based cell counting were used to quantify DC field effects on the deposition of bacterial strains Pseudomonas putida KT2440 and Pseudomonas fluorescens LP6a at varying electrolyte concentrations and weak electric field strengths (0-2 V cm^-1). DC-induced frequency shifts (Δf), dissipation energy (ΔD), and ratios thereof (Δf/ΔD) proved as good indicators of the rigidity of cell attachment. We interpreted QCM-D signals using a theoretical approach by calculating the attractive DLVO-force and the shear and drag forces acting on a bacterium near collector surfaces in a DC electric field. We found that changes in DC-induced deposition of bacteria depended on the relative strengths of electrophoretic drag and electro-osmotic shear forces. This could enable the prediction and electrokinetic control of microbial deposition on surfaces in natural and manmade ecosystems.

The role of medical equipment in the spread of nosocomial infections: a cross-sectional study in four tertiary public health facilities in Uganda

Background

With many medical equipment in hospitals coming in direct contact with healthcare workers, patients, technicians, cleaners and sometimes care givers, it is important to pay close attention to their capacity in harboring potentially harmful pathogens. The goal of this study was to assess the role that medical equipment may potentially play in hospital acquired infections in four public health facilities in Uganda.

Methods

A cross-sectional study was conducted from December 2017 to January 2018 in four public health facilities in Uganda. Each piece of equipment from the neonatal department, imaging department or operating theatre were swabbed at three distinct points: a location in contact with the patient, a location in contact with the user, and a remote location unlikely to be contacted by either the patient or the user. The swabs were analyzed for bacterial growth using standard microbiological methods. Seventeen bacterial isolates were randomly selected and tested for susceptibility/resistance to common antibiotics. The data collected analyzed in STATA version 14.

Results

A total of 192 locations on 65 equipment were swabbed, with 60.4% of these locations testing positive (116/192). Nearly nine of ten equipment (57/65) tested positive for contamination in at least one location, and two out of three equipment (67.7%) tested positive in two or more locations. Of the 116 contaminated locations 52.6% were positive for Bacillus Species, 14.7% were positive for coagulase negative staphylococcus, 12.9% (15/116) were positive for E. coli, while all other bacterial species had a pooled prevalence of 19.8%. Interestingly, 55% of the remote locations were contaminated compared to 66% of the user contacted locations and 60% of the patient contacted locations. Further, 5/17 samples were resistant to at least three of the classes of antibiotics tested including penicillin, glycylcycline, tetracycline, trimethoprim sulfamethoxazole and urinary anti-infectives.

Conclusion

These results provides strong support for strengthening overall disinfection/sterilization practices around medical equipment use in public health facilities in Uganda. There’s also need for further research to make a direct link to the bacterial isolates identified and cases of infections recorded among patients in similar settings.

A meta-analysis of the rates of Staphylococcus aureus and methicillin-resistant S aureus contamination on the surfaces of environmental objects that health care workers frequently touch

BACKGROUND

Health care workers may potentially spread Staphylococcus aureus and methicillin-resistant S aureus (MRSA) to patients by contaminated high-touch items. We aimed to determine the pooled rates of S aureus and MRSA contamination and influencing factors.

METHODS

A literature search of the PubMed, ScienceDirect, Embase, Ovid, and Scopus databases was performed. Pooled contamination rates were determined using random effect models. Subgroup and meta-regression analyses were conducted to identify factors potentially influencing the rates of S aureus and MRSA contamination. Sensitivity and publication bias analyses were performed.

RESULTS

Thirty-eight studies were included in the meta-analysis. The pooled contamination rates were 15.0% (95% confidence interval [CI], 9.8%-21.1%) for S aureus and 5.0% (95% CI, 2.7%-7.7%) for MRSA. The subgroup analyses indicated that the pooled rate of S aureus contamination was significantly higher for studies conducted in South America, in developing countries, and during 2010-2015. The pooled rate of MRSA contamination was significantly higher for studies conducted in Africa. The meta-regression analysis suggested that the pooled rate of S aureus contamination was lower for studies conducted in developed countries (odds ratio, 0.664; 95% CI, 0.509-0.867; P = .004). No bias was found in the publication of the rates of S aureus and MRSA contamination.

CONCLUSIONS

S aureus and MRSA contamination statuses of high-touch items are worrisome and should be paid greater attention. Developing country status was a risk factor for S aureus contamination.

Healthcare Personnel Attire and Devices as Fomites: A Systematic Review

BACKGROUND Transmission of pathogens within the hospital environment remains a hazard for hospitalized patients. Healthcare personnel clothing and devices carried by them may harbor pathogens and contribute to the risk of pathogen transmission. OBJECTIVE To examine bacterial contamination of healthcare personnel attire and commonly used devices. METHODS Systematic review. RESULTS Of 1,175 studies screened, 72 individual studies assessed contamination of a variety of items, including white coats, neckties, stethoscopes, and mobile electronic devices, with varied pathogens including Staphylococcus aureus, including methicillin-resistant S. aureus, gram-negative rods, and enterococci. Contamination rates varied significantly across studies and by device but in general ranged from 0 to 32% for methicillin-resistant S. aureus and gram-negative rods. Enterococcus was a less common contaminant. Few studies explicitly evaluated for the presence of Clostridium difficile. Sampling and microbiologic techniques varied significantly across studies. Four studies evaluated for possible connection between healthcare personnel contaminants and clinical isolates with no unequivocally direct link identified. CONCLUSIONS Further studies to explore the relationship between healthcare personnel attire and devices and clinical infection are needed. Infect Control Hosp Epidemiol 2016;1-7.

Polyethyleneimine Capped Silver Nanoclusters as Efficient Antibacterial Agents

Development of efficient antibacterial agents is critical for human health. In the present study, we investigated the antibacterial activity of polyethyleneimine (PEI)-capped silver nanoclusters (PEI-AgNCs), based on the fact that nanoclusters normally have higher surface-to-volume ratios than traditional nanomaterials and PEI itself has a strong antimicrobial capacity. We synthesized stable silver nanoclusters by altering PEI molecular weight from 0.6 kDa to 25 kDa and characterized them by UV-Vis absorption and fluorescence spectroscopy and high resolution transmission electron microscopy. The sizes of AgNCs were around 2 nm in diameter and were little influenced by the molecular weight of PEIs. The antibacterial abilities of the four PEI-AgNCs were explored on agar plate and in liquid systems. Our results revealed that the antibacterial activity of PEI-AgNCs is excellent and the reduction of PEI molecular weight could result in the increased antibacterial capacity of PEI-AgNCs. Such proposed new materials might be useful as efficient antibacterial agents in practical clinical applications.

A comparison of the recoverable proportion of methicillin-resistant Staphylococcus aureus from two different types of papers

Aim: Paper is used for various purposes in hospitals. Generally, there are two different types of paper, which are commonly used in our facility: wood-free paper, and paper containing wood. We compared the recoverable proportion of methicillin-resistant Staphylococcus aureus (MRSA; ATCC 43300) from the surface of such papers.

Method: The papers were divided into two groups: Group 1: wood-free paper; Group 2: paper containing wood. The papers were contaminated in a standardized procedure with 0.1 mL of a 5×10⁷ CFU MRSA/mL stock solution.

Results: The recoverable proportion of MRSA was higher in the wood-containing papers than in the papers without wood (P=0.043).

Conclusion: This study indicates that if paper is purchased for healthcare facilities it should not contain wood, but rather wood-free paper types should be considered.

Efficacy of commercially available wipes for disinfection of pulse oximeter sensors

BACKGROUND

This study examined the effectiveness of commercially available disinfecting wipes and cosmetic wipes in disinfecting pulse oximeter sensors contaminated with pathogenic bacterial surrogates.

METHODS

Surrogates of potential biological warfare agents and bacterial pathogens associated with hospital-acquired infections (HAIs) were spotted on test surfaces, with and without an artificial test soil (sebum), allowed to dry, and then cleaned with different commercially available cleaning and disinfecting wipes or sterile gauze soaked in water, bleach (diluted 1:10), or 70% isopropanol. The percentage of microbial survival and an analytical estimation of remaining test soil on devices were determined.

RESULTS

Wipes containing sodium hypochlorite as the active ingredient and gauze soaked in bleach (1:10) were the most effective in removing both vegetative bacteria and spores. In the presence of selective disinfectants, sebum had a protective effect on vegetative bacteria, but not on spores.

CONCLUSIONS

The presence of sebum reduces the cleaning efficiency of some commercially available wipes for some select microbes. Various commercial wipes performed significantly better than the designated cleaning agent (70% isopropanol) in disinfecting the oximetry sensor. Cosmetic wipes were not more effective than the disinfecting wipes in removing sebum.

A ten-year surveillance study of carbapenemase-producing Klebsiella pneumoniae in a tertiary care Greek university hospital: predominance of KPC- over VIM- or NDM-producing isolates

Resistance patterns and carbapenemase gene presence among Klebsiella pneumoniae isolates from the University General Hospital of Patras, Greece during a ten-year period were analysed under a surveillance programme for multi-drug-resistant bacteria. From 2005 to 2014, K. pneumoniae isolates from clinically significant specimens were identified by the Vitek 2 Advanced Expert System. Antibiotic susceptibility testing was performed by the agar disc diffusion method and Etest. The strains were tested for the presence of blaVIM, blaIMP, blaKPC, blaNDM and blaOXA-48 genes by PCR. PFGE of chromosomal Xbal DNA digests was performed. A total of 3449 K. pneumoniae isolates were recovered during the last decade. Among them, 1668 (48 %) were carbapenemase-producing: 1333 (80%) K. pneumoniae carbapenemase (KPC)-, 286 (17%) Verona imipenemase (VIM), 45 (3%) KPC- and VIM-, and four New Delhi metallo-beta-lactamase (NDM)-producing. Their resistance rates to gentamicin, colistin and tigecycline were 41%, 23% and 16%, respectively. VIM-producing K. pneumoniae were isolated in 2005 and since 2008 have been endemic. KPC-producing K. pneumoniae (KPC-Kp) isolates were introduced in 2008 and until now represent the predominant carbapenemase-producing K. pneumoniae in our institution. PFGE of 97 KPC-Kp strains identified three types: A, 84 (87%); B, 11 (11%); and E, two (2%). Eleven co-producing KPC and VIM K. pneumoniae isolates belonged to PFGE B. The four NDM-positives were classified to type F. The number of K. pneumoniae bacteraemias increased during the study period, which may be solely attributed to the increase of carbapenemase-producing isolates. The threat of carbapenemase-producing K. pneumoniae emphasizes the urgent need for implementation of infection control measures and budgetary allocations to infection control.