Hospital-acquired infections

Admission screening testing of patients and staff N95 masks are cost-effective in reducing COVID-19 hospital acquired infections

BACKGROUND

COVID-19 outbreaks in acute care settings can have severe consequences for patients due to their underlying vulnerabilities, and can be costly due to additional patient bed days and the need to replace isolating staff. This study assessed the cost-effectiveness of clinical staff N95 masks and admission screening testing of patients to reduce COVID-19 hospital-acquired infections.

METHODS

An agent-based model was calibrated to data on 178 outbreaks in acute care settings in Victoria, Australia between October 2021 and July 2023. Outbreaks were simulated under different combinations of staff masking (surgical, N95) and patient admission screening testing (none, RAT, PCR). For each scenario, average diagnoses, COVID-19 deaths, quality-adjusted life years (QALYs) from discharged patients, and costs (masks, testing, patient COVID-19 bed days, staff replacement costs while isolating) from acute COVID-19 were estimated over a 12-month period.

FINDINGS

Compared to no admission screening testing and staff surgical masks, all scenarios were cost saving with health gains. Staff N95s + RAT admission screening of patients was the cheapest, saving A$78.4M [95%UI 44.4M-135.3M] and preventing 1,543 [1,070-2,146] deaths state-wide per annum. Both interventions were individually beneficial: staff N95s in isolation saved A$54.7M and 854 deaths state-wide per annum, while RAT admission screening of patients in isolation saved A$57.6M and 1,176 deaths state-wide per annum.

INTERPRETATION

In acute care settings, staff N95 mask use and admission screening testing of patients can reduce hospital-acquired COVID-19 infections, COVID-19 deaths, and are cost-saving because of reduced patient bed days and staff replacement needs.

Analysis of the broad-spectrum potential of nitric oxide for antibacterial activity against clinically isolated drug-resistant bacteria

The development of drug-resistant microorganisms is taking a heavy toll on the biomedical world. Clinical infections are costly and becoming increasingly dangerous as bacteria that once responded to standard antibiotic treatment are developing resistance mechanisms that require innovative treatment strategies. Nitric oxide (NO) is a gaseous molecule produced endogenously that has shown potent antibacterial capabilities in numerous research studies. Its multimechanistic antibacterial methods prevent the development of resistance and have shown potential as an alternative to antibiotics. However, there has yet to be a direct comparison study evaluating the antibacterial properties of NO against antibiotic susceptible and antibiotic-resistant clinically isolated bacterial strains. Herein, standardized lab and clinically isolated drug-resistant bacterial strains are compared side-by-side for growth and viability following treatment with NO released from S-nitrosoglutathione (GSNO), an NO donor molecule. Evaluation of growth kinetics revealed complete killing of E. coli lab and clinical strains at 17.5 mM GSNO, though 15 mM displayed >50% killing and significantly reduced metabolic activity, with greater dose dependence for membrane permeability. Clinical P. aeruginosa showed greater susceptibility to GSNO during growth curve studies, but metabolic activity and membrane permeability demonstrated similar effects for 12.5 mM GSNO treatment of lab and clinical strains. MRSA lab and clinical strains exhibited total killing at 17.5 mM treatment, though metabolic activity was decreased, and membrane permeation began at 12.5 mM for both strains. Lastly, both S. epidermidis strains were killed by 15 mM GSNO, with sensitivities in metabolic activity and membrane permeability at 12.5 mM GSNO. The mirrored antibacterial effects seen by the lab and clinical strains of two Gram-negative and two Gram-positive bacteria reveal the translational success of NO as an antibacterial therapy and potential alternative to standard antibiotic treatment.

Incidence, Risk Factors, and Outcomes of Central Line-Associated Bloodstream Infections in Trauma Patients

Introduction: Central line-associated blood stream infection (CLABSI) is a hospital-acquired infection (HAI) associated with increased morbidity and mortality among the general patient population. However, few studies have evaluated the incidence, outcomes, and risk factors for CLABSI in trauma patients. This study aimed to identify the rate of positive (+)CLABSI in trauma patients and risk factors associated with (+)CLABSI. Methods: The 2017-2021 Trauma Quality Improvement Program database was queried for trauma patients aged ≥18 years undergoing central-line placement. We compared patients with (+)CLABSI vs. (-)CLABSI patients. Bivariate and multivariable logistic regression analyses were performed. Results: From 175,538 patients undergoing central-line placement, 469 (<0.1%) developed CLABSI. The (+)CLABSI patients had higher rates of cirrhosis (3.9% vs. 2.0%, p = 0.003) and chronic kidney disease (CKD) (4.3% vs. 2.6%, p = 0.02). The (+)CLABSI group had increased injury severity score (median: 25 vs. 13, p < 0.001), length of stay (LOS) (median 33.5 vs. 8 days, p < 0.001), intensive care unit LOS (median 21 vs. 6 days, p < 0.001), and mortality (23.7% vs. 19.6%, p = 0.03). Independent associated risk factors for (+)CLABSI included catheter-associated urinary tract infection (CAUTI) (odds ratio [OR] = 5.52, confidence interval [CI] = 3.81-8.01), ventilator-associated pneumonia (VAP) (OR = 4.43, CI = 3.42-5.75), surgical site infection (SSI) (OR = 3.66, CI = 2.55-5.25), small intestine injury (OR = 1.91, CI = 1.29-2.84), CKD (OR = 2.08, CI = 1.25-3.47), and cirrhosis (OR = 1.81, CI = 1.08-3.02) (all p < 0.05). Conclusion: Although CLABSI occurs in <0.1% of trauma patients with central-lines, it significantly impacts LOS and morbidity/mortality. The strongest associated risk factors for (+)CLABSI included HAIs (CAUTI/VAP/SSI), specific injuries (small intestine), and comorbidities. Providers should be aware of these risk factors with efforts made to prevent CLABSI in these patients.

Predisposing Factors of Nosocomial Infections in Hospitalized Patients in the United Kingdom: Systematic Review

BACKGROUND

Nosocomial infections are infections incubating or not present at the time of admission to a hospital and manifest 48 hours after hospital admission. The specific factors contributing to the risk of infection during hospitalization remain unclear, particularly for the hospitalized population of the United Kingdom.

OBJECTIVE

The aim of this systematic literature review was to explore the risk factors of nosocomial infections in hospitalized adult patients in the United Kingdom.

METHODS

A comprehensive keyword search was conducted through the PubMed, Medline, and EBSCO CINAHL Plus databases. The keywords included "risk factors" or "contributing factors" or "predisposing factors" or "cause" or "vulnerability factors" and "nosocomial infections" or "hospital-acquired infections" and "hospitalized patients" or "inpatients" or "patients" or "hospitalized." Additional articles were obtained through reference harvesting of selected articles. The search was limited to the United Kingdom with papers written in English, without limiting for age and gender to minimize bias. The above process retrieved 377 articles, which were further screened using inclusion and exclusion criteria following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The retained 9 studies were subjected to critical appraisal using the Critical Appraisal Skills Programme (cohort and case-control studies) and Appraisal Tool for Cross-Sectional Studies (cross-sectional studies) checklists. Finally, 6 eligible publications were identified and used to collect the study findings. A thematic analysis technique was used to analyze data extracted on risk factors of nosocomial infections in hospitalized patients in the United Kingdom.

RESULTS

The risk factors for nosocomial infections that emerged from the reviewed studies included older age, intrahospital transfers, cross-infection, longer hospital stay, readmissions, prior colonization with opportunistic organisms, comorbidities, and prior intake of antibiotics and urinary catheters. Nosocomial infections were associated with more extended hospital stays, presenting with increased morbidity and mortality. Measures for controlling nosocomial infections included the use of single-patient rooms, well-equipped wards, prior screening of staff and patients, adequate sick leave for staff, improved swallowing techniques and nutritional intake for patients, improved oral hygiene, avoiding unnecessary indwelling plastics, use of suprapubic catheters, aseptic techniques during patient care, and prophylactic use.

CONCLUSIONS

There is a need for further studies to aid in implementing nosocomial infection prevention and control.

Metabarcoding approach to identify bacterial community profiling related to nosocomial infection and bacterial trafficking-routes in hospital environments

Nosocomial infections (NIs) appear in patients under medical care in the hospital. The surveillance of the bacterial communities employing high-resolution 16S rRNA profiling, known as metabarcoding, represents a reliable method to establish factors that may influence the composition of the bacterial population during NIs. The present study aimed to utilize high-resolution 16S rRNA profiling to identify high bacterial diversity by analyzing 11 inside and 10 outside environments from the General Hospital of Ribeirão Preto Medical School, Brazil. Our results identified a high bacterial diversity, and among these, the most abundant bacterial genera linked to NIs were Cutibacterium, Streptococcus, Staphylococcus, and Corynebacterium. A Acinetobacter was detected in cafeterias, bus stops, and adult and pediatric intensive care units (ICUs). Data suggest an association between transport and alimentation areas proximal to the hospital ICU environment. Interestingly, the correlation and clusterization analysis showed the potential of the external areas to directly influence the ICU pediatric department microbial community, including the outpatient's clinic, visitor halls, patient reception, and the closest cafeterias. Our results demonstrate that high-resolution 16S rRNA profiling is a robust and reliable tool for bacterial genomic surveillance. In addition, the metabarcoding approach might help elaborate decontamination policies, and consequently reduce NIs.

Extended-Spectrum β-Lactamase and Carbapenemase-Producing Gram-Negative Bacteria and Associated Factors Among Patients Suspected of Community and Hospital-Acquired Urinary Tract Infections at Ayder Comprehensive Specialized Hospital, Tigrai, Ethiopia

Background

Little is known about bacteria that produce extended-spectrum beta-lactamases (ESBLs) and carbapenemase in patients with urinary tract infections (UTIs) in Tigrai, Ethiopia. The aim of this study was to describe the magnitude of ESBL- and carbapenemase -producing gram-negative bacteria among patients suspected of community- and hospital-acquired UTIs at a referral hospital in Tigrai, Ethiopia.

Methods

A cross-sectional study was conducted at Ayder Comprehensive Specialized hospital from January 2020 to June 2020. A 10-20 mL sample of morning mid-stream and catheter urine was collected from consenting participants. Urine samples were cultured on cysteine lactose electrolyte deficient medium and MacConkey agar, and bacteria were identified using standard microbiological protocols. The Kirby-Bauer disk diffusion method was used for antimicrobial susceptibility testing. The combination disk and modified Hodge tests were used detect ESBL and carbapenemase production, respectively. The data was entered into EPI 3.1 software and analyzed using SPSS version 21.

Results

Overall, 67 gram-negative bacteria were recovered from 64 participants. Escherichia coli was the predominant isolate (68.6%), followed by Klebsiella pneumoniae (22.4%), while ESBL production was found in both Escherichia coli and Klebsiella pneumoniae (52.2% and 86.7%, respectively). Isolates recovered from patients with hospital-acquired UTIs were more likely to produce ESBLs (AOR= 16.2; 95% CI: 2.95-89.5). Carbapenemase was produced by 4.3% of E. coli and 20% of Klebsiella pneumoniae isolates. High resistance rates were found against tetracycline (84.8%), ampicillin (78.3%), amoxicillin/clavulanic acid (58.7%) for Escherichia coli isolates and against ampicillin (93.3%), sulphamethexazole trimethoprim (93.3%), cefotaxime (86.6%), and ceftazidime (86.6%), and tetracycline (73.3%) for Klebsiella pneumoniae.

Conclusion

Most UTIs were caused by ESBL-producing bacteria, especially those that were related to healthcare. Microbiological-based therapy for patients with UTIs is essential at our study site due to high rates of ESBL and significant carbapenemase production with concomitant high rates of drug resistance to several antibiotics.

Clinical Impact and Risk Factors of Intensive Care Unit-Acquired Nosocomial Infection: A Propensity Score-Matching Study from 2018 to 2020 in a Teaching Hospital in China

Purpose

Nosocomial infection (NI) is associated with poor prognosis. The present study assessed the clinical and microbiological characteristics of NI patients in the intensive care unit (ICU) and investigated the clinical impact and risk factors for NI in ICU patients.

Patients and Methods

An observational study was conducted in an adult general ICU. The electronic medical records of all patients admitted to the ICU for >2 days from 2018-2020 were analyzed retrospectively. Multivariate regression models were used to analyze the risk factors for NI in ICU patients. Propensity score-matching (PSM) was used to control the confounding factors between the case and control groups, thus analyzing the clinical impact of NIs.

Results

The present study included 2425 patient admissions, of which 231 (9.53%) had NI. Acinetobacter baumannii (33.0%) was the most common bacteria. Long-term immunosuppressive therapy, disturbance of consciousness, blood transfusion, multiple organ dysfunction syndromes (MODS), treatment with three or more antibiotics, mechanical ventilation (MV), tracheotomy, the urinary catheter (UC), nasogastric catheter, and central venous catheter (CVC) were risk factors for NI in the ICU patients. After PSM, patients with NI had a prolonged length of stay (LOS) in the ICU and hospital, significant hospitalization expenses (all p<0.001), increased mortality (p=0.027), and predicted mortality (p=0.007). The differences in the ICU and hospital LOSs among three pathogens were statistically significant (p<0.001); the results of the Escherichia coli infection group were lower than the other two pathogenic groups.

Conclusion

NI was associated with poor outcomes. The risk factors for NI identified in this study provided further insight into preventing NI.

Reducing the Healthcare-Associated Infections in a Rehabilitation Hospital under the Guidance of Lean Six Sigma and DMAIC

The reduction of healthcare-associated infections (HAIs) is one of the most important issues in the healthcare context for every type of hospital. In three operational units of the Scientific Clinical Institutes Maugeri SpA SB, a rehabilitation hospital in Cassano delle Murge (Italy), some corrective measures were introduced in 2017 to reduce the occurrence of HAIs. Lean Six Sigma was used together with the Define, Measure, Analyze, Improve, Control (DMAIC) roadmap to analyze both the impact of such measures on HAIs and the length of hospital stay (LOS) in the Rehabilitative Cardiology, Rehabilitative Neurology, Functional Recovery and Rehabilitation units in the Medical Center for Intensive Rehabilitation. The data of 2415 patients were analyzed, considering the phases both before and after the introduction of the measures. The hospital experienced a LOS reduction in both patients with and without HAIs; in particular, Cardiology had the greatest reduction for patients with infections (-7 days). The overall decrease in HAIs in the hospital was 3.44%, going from 169 to 121 cases of infections. The noteworthy decrease in LOS implies an increase in admissions and in the turnover indicator of the hospital, which has a positive impact on the hospital management as well as on costs.

Type1 and 3 fimbriae phenotype and genotype as suitable markers for uropathogenic bacterial pathogenesis via attachment, cell surface hydrophobicity, and biofilm formation in catheter-associated urinary tract infections (CAUTIs)

Objective(s):

Catheters are one of the factors for complicated urinary tract infections. Uropathogenic bacteria can attach to the catheter via cell surface hydrophobicity (CSH), form biofilms, and remain in urinary tract. The study was evaluated phenotypic and genotypic characteristics of fimbriae in Klebsiella pneumoniae and uropathogenic Escherichia coli (UPEC) isolates from patients with catheter-associated urinary tract infections (CAUTIs) and their association with biofilm formation.

Materials and Methods:

Urine specimens were collected through catheters in patients with CAUTIs. Sixty bacterial isolates were identified by biochemical tests. For determination of biofilm formation a tissue culture plate was used. Microbial adhesion to hydrocarbons (MATH) was conducted for CSH determination. The mannose-sensitive haemagglutination (MSHA) and mannose-resistant haemagglutination (MRHA) were determined for type 1 and type 3 fimbriae. Finally, the presence of genes encoding fimbriae was determined by PCR.

Results:

All isolates showed strong CSH, biofilm capacity and MRHA phenotype. The results showed that 20% of UPEC and 23% of K. pneumoniae isolates contained MSHA phenotypes. There was a significant association between biofilm formation and MSHA phenotype in UPEC isolates. The frequency of fimA (80%) and fimH (96.6%) in K. pneumoniae isolates was higher than UPEC isolates. Both types of bacterial isolates with MSHA phenotypes harbored the fimH gene.

Conclusion:

The phenotypic and genotypic characteristics of two bacterial species were highly similar. Also, the type of fimbriae affected bacterial biofilm formation through catheterization. It seems that fimH and mrk gene cluster subunits are suitable markers for identifying bacterial pathogenesis.

Catheter-Associated Urinary Tract Infections in the Adult Patient Group: A Qualitative Systematic Review on the Adopted Preventative and Interventional Protocols From the Literature

Catheter-associated urinary tract infections (CA-UTIs) are among the most common nosocomial infections acquired by patients in health care settings. A significant risk factor for CA-UTIs is the duration of catheterization. To summarize the current strategies and interventions in reducing urinary tract infections associated with urinary catheters, use and the need for re-catheterization on the rate of CA-UTIs, we performed a systematic review. A rapid evidence analysis was carried out in the Medline (via Ovid) and the Cochrane Library for the periods of January 2005 till April 2021. The main inclusion criterion required to be included in this review was symptomatic CA-UTI in adults as a primary or secondary outcome in all the included studies. Only randomized trials and systematic reviews were included, reviewed, evaluated, and abstracted data from the 1145 articles that met the inclusion criteria. A total of 1145 articles were identified, of which 59 studies that met the inclusion criteria were selected. Studies of relevance to CA-UTIs were based on: duration of catheterization, indication for catheterization, catheter types, UTI prophylaxis, educational proposals and approaches, and mixed policies and interventions. The duration of catheterization is the contributing risk factor for CA-UTI incidence; longer-term catheterization should only be undertaken where needed indications. The indications for catheterization should be based on individual base to base cases. The evidence for systemic prophylaxis instead of when clinically indicated is still equivocal. However, antibiotic-impregnated catheters reduce the risk of symptomatic CA-UTIs and bacteriuria and are more cost-effective than other impregnated catheter types. Antibiotic resistance, potential side effects and increased healthcare costs are potential disadvantages of implementing antibiotic prophylaxis. Multiple interventions and measures such as reducing the number of catheters in place, removing catheters at their earliest, clinically appropriate time, reducing the number of unnecessary catheters inserted, decrease antibiotic administration unless clinically needed, raising more awareness and provide training of nursing personnel on the latest guidelines, can effectively lower the incidence of CA-UTIs.

Characteristics of candidemia in COVID-19 patients; increased incidence, earlier occurrence and higher mortality rates compared to non-COVID-19 patients

Severe COVID‐19 patients in ICU are at high risk for candidemia due to exposure to multiple risk factors for candidemia. We aimed to compare the incidence of candidemia in ICU patients with and without COVID‐19, and to investigate epidemiologic and clinical characteristics of candidemia patients and risk factors for mortality in candidemia patients. This retrospective study was conducted in patients followed in the ICUs of Ankara City Hospital for 2 years, divided into pre‐pandemic and pandemic periods. The incidence (event per 1000 patient‐days) and epidemiology of candidemia, clinical and laboratory characteristics of patients were compared in COVID‐19 and non‐COVID‐19 groups. Candidemia incidence was higher in the COVID‐19 group (2.16, 95% CI 1.77–2.60) than the non‐COVID‐19 group (1.06, 95% CI 0.89–0.125) (p < .001). A total of 236 candidemia episodes (105 in COVID‐19 patients and 131 in non‐COVID‐19 patients) were detected during the study periods. COVID‐19 cases had a higher rate of corticosteroid use (63.8% vs. 9.9%, p < .001). Epidemiology of candidemia and antifungal susceptibility were similar. Candidemia developed 2 weeks earlier in COVID‐19 groups and resulted in higher mortality (92.5% vs. 79.4%, p .005). One‐third of candidemia patients died before receiving any antifungal treatment, and this rate was higher in the COVID‐19 group. In multivariate logistic regression analysis, corticosteroid use, presence of sepsis and age older than 65 years were independent risk factors for mortality in candidemia patients. Candidemia with high mortality is a more serious problem for COVID‐19 patients due to its increased incidence, earlier occurrence and a higher rate of mortality.

Reliability of Symptoms and Dipstick for Postoperative Catheter-Associated Urinary Tract Infections

OBJECTIVE

The aim of the study was to determine the diagnostic reliability of patient symptoms and urine dipstick results, including blood, leukocyte esterase, and nitrite, in diagnosing postoperative catheter-associated urinary tract infections (CAUTIs) after gynecologic surgery.

METHODS

A prospective cohort study of patients undergoing gynecologic surgeries who required short-term (>24 hours) postoperative catheterization was conducted. Patients completed a questionnaire regarding symptoms. Urine dipstick analysis was completed on catheterized urine samples and urine was sent for culture for all patients. Positive likelihood ratios (LRs) were used to examine diagnostic reliability of patient symptoms and urine dipstick results in diagnosing postoperative CAUTIs.

RESULTS

Fifty-seven patients with postoperative short-term indwelling catheterization were recruited, 25 (44%) of whom had CAUTIs diagnosed by urine culture at recruitment and 32 (56%) of whom did not have CAUTIs. Urine dipstick parameters were found to successfully diagnose CAUTIs, with positive LRs of 1.44 (95% confidence interval [CI], 1.04-1.99), 6.77 (95% CI, 2.23-20.52), and 9.47 (95% CI, 1.23-72.69) for blood, leukocyte esterase, and nitrite, respectively. The combination of leukocyte esterase and nitrite yielded a positive LR of 9.48 (95% CI, 2.62-34.25). Individual symptoms, alone or in combination, did not successfully diagnose positive urine culture (positive LRs <1.8).

CONCLUSIONS

Urine dipstick parameters are reliable diagnostic tests for diagnosing postoperative CAUTIs after gynecologic surgery, particularly when in combination. Patient symptoms have little diagnostic value for positive urine cultures in catheterized patients after gynecologic surgery.

Antimicrobial, Antioxidant, and Cytotoxic Activities of Juglans regia L. Pellicle Extract

The difficulty to treat resistant strains-related hospital-acquired infections (HAIs) promoted the study of phytoextracts, known sources of bioactive molecules. Accordingly, in the present study, the pharmacological activities of Juglans regia (L.) pellicle extract (WPE) were investigated. The antiviral effect was tested against Herpes simplex virus type 1 and 2, Poliovirus 1, Adenovirus 2, Echovirus 9, Coxsackievirus B1 through the plaque reduction assay. The antibacterial and antifungal activities were evaluated against medically important strains, by the microdilution method. DPPH and superoxide dismutase (SOD)s-like activity assays were used to determine the antioxidant effect. Besides, the extract was screened for cytotoxicity on Caco-2, MCF-7, and HFF1 cell lines by the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay. The total phenolic and flavonoid contents were also evaluated. Interestingly, WPE inhibited Herpes simplex viruses (HSVs) replication, bacterial and fungal growth. WPE showed free radical scavenging capacity and inhibited superoxide anion formation in a dose-dependent manner. These effects could be attributed to the high content of phenols and flavonoids, which were 0.377 ± 0.01 mg GE/g and 0.292 ± 0.08 mg CE/g, respectively. Moreover, WPE was able to reduce Caco-2 cell viability, at both 48 h and 72 h. The promising results encourage further studies aimed to better elucidate the role of WPE in the prevention of human infectious diseases.

Methicillin Resistant Staphylococcus aureus and public fomites: a review

Staphylococcus genus is a Gram-positive coccus normally associated with skin and mucous membranes of warm-blooded animals. It is part of the commensal human microflora, or found in animals, or contaminating surfaces in the community and hospital settings. Staphylococcus aureus is the most pathogenic species belonging to this genus, as it possesses a collection of virulence factors that are expressed solely to evade the immune system. The increase in the misuse of antimicrobial agents predisposed S. aureus to develop antibiotic resistance, including the resistance to methicillin which led to the emergence of Methicillin-Resistant S. aureus (MRSA). MRSA is considered one of the most dangerous nosocomial pathogens causing many hard to treat infections in hospitals and was named as Hospital Associated MRSA (HA-MRSA). Over the past 20-25 years, MRSA was isolated from community settings and thus Community Associated MRSA (CA-MRSA) has emerged. Inside hospitals, MRSA has been isolated from fomites in contact with patients, as well as staff's protective and personal items. This review highlights the worldwide prevalence of MRSA on fomites within the contexts of hospital and community settings.

Incidence of Staphylococcus aureus Infections After Elective Surgeries in US Hospitals

Background

Although Staphylococcus aureus is a leading cause of postsurgical infections, national estimates of these infections after elective surgeries based on microbiology data are limited. This study assessed cumulative 180-day postsurgical S. aureus incidence in real-world hospital settings.

Methods

A retrospective study of adults (≥18 years) undergoing inpatient or hospital-based outpatient elective surgeries from 1/7/2010–30/6/2015 at hospitals (N = 181) reporting microbiology results in the Premier Healthcare Database (PHD). 86 surgical categories were identified from the National Healthcare Safety Network procedures. We classified positive S. aureus cultures using a hierarchy (bloodstream [BSI], surgical site [SSI], and all other types [urinary tract, respiratory, other/unknown site]) and calculated incidence (number of infections divided by the number of elective surgery discharges). We estimated national infection case volumes by multiplying incidence by national inpatient elective surgical discharge estimates using the entire PHD and weights based on hospital characteristics.

Results

Following 884 803 inpatient elective surgical discharges, 180-day S. aureus infection incidence was 1.35% (0.30% BSI, 0.74% SSI no BSI, 0.32% all other types only). Among 1 116 994 hospital-based outpatient elective surgical discharges, 180-day S. aureus incidence was 1.19% (0.25% BSI, 0.75% SSI no BSI, 0.19% all other types only). Methicillin resistance was observed in ~45% of the S. aureus infections. We estimated 55 764 S. aureus postsurgical infections occurred annually in the US following 4.2 million elective inpatient surgical discharges.

Conclusions

The high burden of S. aureus infections after both inpatient and outpatient elective surgeries highlights the continued need for surveillance and novel infection prevention efforts.

Perceptions of Patients, Health Care Workers, and Environmental Services Staff Regarding Ultraviolet Light Room Decontamination Devices

BACKGROUND

Mobile ultraviolet C (UV-C) room decontamination devices are widely used in health care facilities; however, there is limited information on the perceptions of patients, health care workers (HCWs), and environmental services staff (EVS-staff) regarding their use for environmental decontamination.

METHODS

An anonymous questionnaire was administered to participants in 4 medical/surgical units of a tertiary care hospital where UV-C devices were deployed for a 6-month period. Survey questions assessed perceptions regarding the importance of environmental disinfection, effectiveness of UV-C decontamination, willingness to delay hospital admission in order to use UV-C, and safety of UV-C devices.

RESULTS

Questionnaires were completed by 102 patients, 130 HCWs, and 47 EVS-staff. All of the HCWs and EVS-staff and 99% of the patients agreed that environmental disinfection is important to reduce the risk of exposure from contaminated surfaces. Ninety-eight percent of the EVS-staff, 89% of the HCWs, and 96% of the patients felt that the use of UV-C as an adjunct to routine cleaning increased confidence that rooms are clean. Ninety-four percent of the EVS-staff, 85% of the HCWs, and 90% of the patients expressed a willingness to delay being admitted to a room in order to have UV-C decontamination completed. Seventy-nine percent of the EVS-staff, 76% of the HCWs, and 86% of the patients had no concerns about the safety of UV-C devices.

CONCLUSIONS

Patients, HCWs, and EVS-staff agreed that environmental disinfection is important and that UV-C devices are efficacious and safe. Educational tools are needed to allay safety concerns expressed by a minority of HCWs and EVS-staff.

(p)ppGpp and CodY Promote Enterococcus faecalis Virulence in a Murine Model of Catheter-Associated Urinary Tract Infection

Catheter-associated urinary tract infections (CAUTIs) are one of the most frequent types of infection found in the hospital setting that can develop into serious and potentially fatal bloodstream infections. One of the infectious agents that frequently causes complicated CAUTI is the bacterium Enterococcus faecalis, a leading cause of hospital-acquired infections that are often difficult to treat due to the exceptional multidrug resistance of some isolates. Understanding the mechanisms by which E. faecalis causes CAUTI will aid in the discovery of new druggable targets to treat these infections. In this study, we report the importance of two nutrient-sensing bacterial regulators, named (p)ppGpp and CodY, for the ability of E. faecalis to infect the catheterized bladder of mice.

In Firmicutes, the nutrient-sensing regulators (p)ppGpp, the effector molecule of the stringent response, and CodY work in tandem to maintain bacterial fitness during infection. Here, we tested (p)ppGpp and codY mutant strains of Enterococcus faecalis in a catheter-associated urinary tract infection (CAUTI) mouse model and used global transcriptional analysis to investigate the relationship of (p)ppGpp and CodY. The absence of (p)ppGpp or single inactivation of codY led to lower bacterial loads in catheterized bladders and diminished biofilm formation on fibrinogen-coated surfaces under in vitro and in vivo conditions. Single inactivation of the bifunctional (p)ppGpp synthetase/hydrolase rel did not affect virulence, supporting previous evidence that the association of (p)ppGpp with enterococcal virulence is not dependent on the activation of the stringent response. Inactivation of codY in the (p)ppGpp⁰ strain restored E. faecalis virulence in the CAUTI model as well as the ability to form biofilms in vitro. Transcriptome analysis revealed that inactivation of codY restores, for the most part, the dysregulated metabolism of (p)ppGpp⁰ cells. While a clear linkage between (p)ppGpp and CodY with expression of virulence factors could not be established, targeted transcriptional analysis indicates that a possible association between (p)ppGpp and c-di-AMP signaling pathways in response to the conditions found in the bladder may play a role in enterococcal CAUTI. Collectively, data from this study identify the (p)ppGpp-CodY network as an important contributor to enterococcal virulence in catheterized mouse bladder and support that basal (p)ppGpp pools and CodY promote virulence through maintenance of a balanced metabolism under adverse conditions.

IMPORTANCE Catheter-associated urinary tract infections (CAUTIs) are one of the most frequent types of infection found in the hospital setting that can develop into serious and potentially fatal bloodstream infections. One of the infectious agents that frequently causes complicated CAUTI is the bacterium Enterococcus faecalis, a leading cause of hospital-acquired infections that are often difficult to treat due to the exceptional multidrug resistance of some isolates. Understanding the mechanisms by which E. faecalis causes CAUTI will aid in the discovery of new druggable targets to treat these infections. In this study, we report the importance of two nutrient-sensing bacterial regulators, named (p)ppGpp and CodY, for the ability of E. faecalis to infect the catheterized bladder of mice.

Molecular characterization, serotypes and phenotypic and genotypic evaluation of antibiotic resistance of the Klebsiella pneumoniae strains isolated from different types of hospital-acquired infections

Purpose: Virulent and resistant Klebsiella pneumoniae strains are considered as one of the most significant causes of hospital-acquired infections. The present investigation was done to study the distribution of virulence factors, capsule serotypes and phenotypic and genotypic evaluation of antibiotic resistance of the K. pneumoniae strains isolated from hospital-acquired infections.

Patients Materials and methods: Two hundred and sixty different types of hospital-acquired infections were collected and cultured. Antibiotic resistance pattern of K. pneumoniae isolates and their molecular characterization were studied using disk diffusion and PCR, respectively.

Results: One hundred and fifty out of 260 (44.22%) hospital-acquired infections harbored K. pneumoniae. Urine samples (63.75%) had the highest prevalence of K. pneumoniae, while wound (33.33%) had the lowest. K. pneumoniae strains harbored the highest prevalence of resistance against ampicillin (100%), cefuroxime (100%), amoxicillin/clavulanic acid (95.65%) and ceftazidime (95.52%). FimH-1 (93.04%), traT (92.17%), mrkD (84.34%), and entB (80.86%) were the most commonly detected virulence genes. AcrAB (96.52%) and tolC (85.21%) were the most commonly detected antibiotic resistance genes. Prevalence of ompK35 and ompK36 virulence genes were 75.65% and 79.13%, respectively. Prevalence of K1 and K2-positive serotypes were 27.82% and 6.96%, respectively.

Conclusions: High prevalence of resistance against several types of antibiotics and simultaneous presence of some virulence factors and multi-drug resistance genes pose an important public health issue.

Hospital-Acquired Infections Under Pay-for-Performance Systems: an Administrative Perspective on Management and Change

PURPOSE OF REVIEW

The purpose of this review is to explore the impact of hospital-acquired infection on payment under pay-for-performance systems, and provide perspective on the role of administrators in infection prevention.

RECENT FINDINGS

Hospital-acquired infections continue to pose a serious threat to patient safety and to the fiscal viability of healthcare facilities under pay-for-performance systems. There is mixed evidence that use of pay-for-performance systems leads to prevention of hospital-acquired conditions. Use of evidence-based guidelines has been shown to reduce hospital-acquired infections. Increasing use of pay-for-performance (PFP) systems results in potential loss of reimbursement for healthcare organizations that fail to prevent hospital-acquired infections (HAI). Healthcare administrators must work with front-line providers and infection control staff to establish and maintain evidence-based infection prevention policy. Additionally, infection control policy should be regularly updated to reflect best practices, and proper change management techniques should be employed in order to mobilize and empower staff to increase their ability to prevent hospital-acquired infections.

[Prevent bacteria from communicating: Divide to cure]

Quorum Sensing (QS) is a communication system used by numerous bacteria to synchronize their behavior according to the cell density. In this way, bacteria secrete and sense small mediating molecules, called autoinducers (AI), which concentration increases in the environment proportionally to bacterial cell number. QS induces major physiological and phenotypic changes such as virulence induction and biofilm formation. Biofilm represents a physical barrier which shelters bacteria poorly sensitive to antimicrobial treatments and favors the apparition of resistance mechanisms. Disturbing QS is referred to as quorum quenching (QQ). This strategy is used by microorganisms themselves to prevent the development of specific group behaviors. Two strategies are mainly employed: the use of quorum sensing inhibitors (QSI) and of quorum quenching enzymes (QQE) that degrades AI. Many studies have been dedicated to identifying QSI (natural or synthetic) as well as QQE and demonstrating their anti-virulence and anti-biofilm effects on numerous bacterial species. Synergistic effects between QQ and traditional treatments such as antibiotherapy or with reemerging phage therapy have been put forward. The efficiency of numerous QSI and QQE was thereby demonstrated either with in vitro or in vivo animal models leading to the development of medical devices containing QSI and QQE to improve already existing treatments.

Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective

Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS) to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs), as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs) to block the action of AIs and quorum quenching (QQ) enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.

Assessing students' knowledge of healthcare-associated infections: a global perspective

The aim of this review was to explore students' knowledge of healthcare-associated infections (HCAIs) from a global perspective. HCAIs may be the result of treatment in or contact with healthcare or social care settings and have been shown to cause an increase in morbidity, mortality and increased length of hospital stay. Student placements may involve interactions between university students, patients and/or health professionals and this may be a source of cross-contamination of the microbial agents that cause HCAIs. This situation may be exacerbated in some countries owing to variations in the levels of infrastructure development, knowledge, and economic status. A literature search was carried out, resulting in 12 studies selected for review. Findings were organised into two themes: nursing students' knowledge of HCAIs and students in other health-related subjects' knowledge of HCAIs. Nursing students' knowledge was adequate in some aspects of HCAIs, although poor in certain areas. Knowledge of HCAIs varied between students studying different health-related subjects. Curriculum differences between the student groups may account for this variation. A review of the curricula for healthcare students should ensure they include training and practical skills in the prevention of HCAIs, including modes of disease transmission, handwashing and disinfection techniques.

Host and bacterial proteases influence biofilm formation and virulence in a murine model of enterococcal catheter-associated urinary tract infection

Enterococcus faecalis is a leading causative agent of catheter-associated urinary tract infection (CAUTI), the most common hospital-acquired infection. Its ability to grow and form catheter biofilm is dependent upon host fibrinogen (Fg). Examined here are how bacterial and host proteases interact with Fg and contribute to virulence. Analysis of mutants affecting the two major secreted proteases of E. faecalis OG1RF (GelE, SprE) revealed that while the loss of either had no effect on virulence in a murine CAUTI model or for formation of Fg-dependent biofilm in urine, the loss of both resulted in CAUTI attenuation and defective biofilm formation. GelE⁻, but not SprE⁻ mutants, lost the ability to degrade Fg in medium, while paradoxically, both could degrade Fg in urine. The finding that SprE was activated independently of GelE in urine by a host trypsin-like protease resolved this paradox. Treatment of catheter-implanted mice with inhibitors of both host-derived and bacterial-derived proteases dramatically reduced catheter-induced inflammation, significantly inhibited dissemination from bladder to kidney and revealed an essential role for a host cysteine protease in promoting pathogenesis. These data show that both bacterial and host proteases contribute to CAUTI, that host proteases promote dissemination and suggest new strategies for therapeutic intervention.

Identifying bacterial and host enzymes that support biofilm formation may help prevent urinary tract infections caused by catheters. Enterococcus faecalis bacteria is a leading cause of catheter-associated urinary tract infections, the most common type of hospital-acquired infections. Michael Caparon and colleagues at Washington University School of Medicine in Missouri, USA, studied these infections in mice. They examined the effects of two protein-degrading enzymes, both from the bacterium and one can be activated by urine trypsin-like protease from the animals. Mutations that impaired either one of the enzymes had no effect on the infection, but when both the bacterial enzymes were impaired by mutation the formation of biofilms was significantly reduced. Treating the mice with chemicals that inhibited both bacterial and host enzymes dramatically reduced catheter-induced inflammation and related problems. This suggests drugs targeting these enzymes could be useful in clinical care.

Cardiothoracic Critical Care

High-value CCC is rapidly evolving to meet the demands of increased patient acuity and to incorporate advances in technology. The high-performing CCC system and culture should aim to learn quickly and continuously improve. CCC demands a proactive, interactive, precise, an expert team, and continuity.

Tunable Ag@SiO2 core–shell nanocomposites for broad spectrum antibacterial applications

Silica encapsulated silver nanoparticle core–shell nanocomposites of tunable dimensions were synthesised via a one-pot reverse microemulsion route to achieve controlled release of Ag⁺ ions for broad spectrum antibacterial application.

Highly Efficient F, Cu doped TiO2 anti-bacterial visible light active photocatalytic coatings to combat hospital-acquired infections

Bacterial infections are a major threat to the health of patients in healthcare facilities including hospitals. One of the major causes of patient morbidity is infection with Staphylococcus aureus. One of the the most dominant nosocomial bacteria, Methicillin Resistant Staphylococcus aureus (MRSA) have been reported to survive on hospital surfaces (e.g. privacy window glasses) for up to 5 months. None of the current anti-bacterial technology is efficient in eliminating Staphylococcus aureus. A novel transparent, immobilised and superhydrophilic coating of titanium dioxide, co-doped with fluorine and copper has been prepared on float glass substrates. Antibacterial activity has demonstrated (by using Staphylococcus aureus), resulting from a combination of visible light activated (VLA) photocatalysis and copper ion toxicity. Co-doping with copper and fluorine has been shown to improve the performance of the coating, relative to a purely fluorine-doped VLA photocatalyst. Reductions in bacterial population of log₁₀ = 4.2 under visible light irradiation and log₁₀ = 1.8 in darkness have been achieved, compared with log₁₀ = 1.8 under visible light irradiation and no activity, for a purely fluorine-doped titania. Generation of reactive oxygen species from the photocatalytic coatings is the major factor that significantly reduces the bacterial growth on the glass surfaces.

Trachyspermum ammi (L.) Sprague

Resistance to antibacterial agents has become a serious problem for global health. The current study evaluated the antimicrobial activities of essential oil and respective fractions of Trachyspermum ammi (L.) Sprague. Seeds of the essential oil were extracted and fractionated using column chromatography. All fractions were then analyzed by gas chromatography/mass spectrometry. Antifungal and antibacterial activities of the oil and its fractions were assessed using microdilution method. Compounds γ-terpinene (48.07%), ρ-cymene (33.73%), and thymol (17.41%) were determined as major constituents. The effect of fraction II was better than total essential oil, fraction I, and standard thymol. The greater effect of fraction II compared to standard thymol showed the synergistic effects of the ingredients in this fraction. As this fraction and also total oil were effective on the studied microorganism, the combination of these products with current antimicrobial agents could be considered as new antimicrobial compounds in further investigations.

Rapid identification and discrimination of bacterial strains by laser induced breakdown spectroscopy and neural networks

Identification and discrimination of bacterial strains of same species exhibiting resistance to antibiotics using laser induced breakdown spectroscopy (LIBS) and neural networks (NN) algorithm is reported. The method has been applied to identify 40 bacterial strains causing hospital acquired infections (HAI), i.e. Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Salmonella typhimurium, Salmonella pullurum and Salmonella salamae. The strains analyzed included both isolated from clinical samples and constructed in laboratory that differ in mutations as a result of their resistance to one or more antibiotics. Small changes in the atomic composition of the bacterial strains, as a result of their mutations and genetic variations, were detected by the LIBS-NN methodology and led to their identification and classification. This is of utmost importance because solely identification of bacterial species is not sufficient for disease diagnosis and identification of the actual strain is also required. The proposed method was successfully able to discriminate strains of the same bacterial species. The optimized NN models provided reliable bacterial strain identification with an index of spectral correlation higher than 95% for the samples analyzed, showing the potential and effectiveness of the method to address the safety and social-cost HAI-related issue.

Cross-sectional study on surveillance of surgical site infections after vascular surgery

Aims: To determine the incidence and risk factors for surgical site infections (SSI) after vascular surgery, to evaluate the Dutch safety bundle to reduce adverse complications and to analyze causative microorganisms of SSIs. Materials & methods: The 3.5-year study was divided into two periods: the control period (before bundle implementation) and intervention period (after implementation). Postdischarge surveillance was performed until 30 days after surgery. Causative microorganisms from in-hospital wound swabs were determined. SSI rates between both periods were compared and a risk analysis was carried out by performing a logistic regression. Results: The study included 1719 operations. The in-hospital SSI rate increased significantly over time. Out of 140 SSIs, 39% were diagnosed postdischarge. Risk factors were diabetes, age >60 years and operations classified as contaminated or dirty. Pseudomonas aeruginosa susceptibility was the highest for gentamicin (97%). All Staphylococcus aureus were methicillin susceptible. Conclusion: As patient demographics are important to determine the effectiveness of infection preventive measures, (postdischarge) surveillance is important for developing SSI interventions.

Nosocomial Gram-positive antimicrobial susceptibility pattern at a referral teaching hospital in Tehran, Iran

Aims: The aim of the study was to evaluate epidemiology and susceptibility patterns of nosocomial Gram-positive infections in a referral teaching hospital. Methods: Over a 1 year period, Gram-positive microorganisms isolated from specimens of hospitalized patients with documented nosocomial infection underwent antimicrobial susceptibility testing using the disk diffusion test. In addition, possible risk factors for developing multidrug-resistant bacteria were evaluated. Results: During the study period, a total of 137 nosocomial infections were detected. Staphylococcus aureus was the most frequently isolated microorganism (56.2%), followed by Enterococcus spp. (21.9%) and Staphylococcus epidermidis (15.3%). All S. aureus strains were sensitive to vancomycin, teicoplanin, linezolid and chloramphenicol. More than 50% of enterococci strains were resistant to vancomycin and teicoplanin. Possible risk factors for multidrug resistance among isolated pathogens were history of antibiotic use and intubation of patient for mechanical ventilation. Conclusion: This study showed high rates of antimicrobial resistance among nosocomial Gram-positive pathogens, complicating antibiotic therapy and its outcomes.

Original submitted 26 March 2012; Revised submitted 27 April 2012