Can antibiotic-resistant nosocomial infections be controlled?

Innovative Phospholipid Carriers: A Viable Strategy to Counteract Antimicrobial Resistance

The overuse and misuse of antibiotics have led to the emergence and spread of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pan-drug-resistant (PDR) bacteria strains, usually associated with poorer patient outcomes and higher costs. In order to preserve the usefulness of these life-saving drugs, it is crucial to use them appropriately, as also recommended by the WHO. Moreover, innovative, safe, and more effective approaches are being investigated, aiming to revise drug treatments to improve their pharmacokinetics and distribution and to reduce the onset of drug resistance. Globally, to reduce the burden of antimicrobial resistance (AMR), guidelines and indications have been developed over time, aimed at narrowing the use and diminishing the environmental spread of these life-saving molecules by optimizing prescriptions, dosage, and times of use, as well as investing resources into obtaining innovative formulations with better pharmacokinetics, pharmacodynamics, and therapeutic results. This has led to the development of new nano-formulations as drug delivery vehicles, characterized by unique structural properties, biocompatible natures, and targeted activities such as state-of-the-art phospholipid particles generally grouped as liposomes, virosomes, and functionalized exosomes, which represent an attractive and innovative delivery approach. Liposomes and virosomes are chemically synthesized carriers that utilize phospholipids whose nature is predetermined based on their use, with a long track record as drug delivery systems. Exosomes are vesicles naturally released by cells, which utilize the lipids present in their cellular membranes only, and therefore, are highly biocompatible, with investigations as a delivery system having a more recent origin. This review will summarize the state of the art on microvesicle research, liposomes, virosomes, and exosomes, as useful and effective tools to tackle the threat of antibiotic resistance.

Silver-dendrimer nanocomposite as emerging therapeutics in anti-bacteria and beyond

To develop next-generation nanomedicine, theranostic nanotherapeutic strategies are increasingly being emphasized. In recent years, it is observed that the effective lifetime of anti-bacterial and anti-cancer agent is diminishing, which undermines the economic incentives necessary for clinical development and therapeutic applications. Thus, novel formulations ought to not only kill drug resistant strains and cancerous cells but also inhibit their formation. Recently, metallic nanoparticles [for example- silver (Ag) nanoparticles] have been widely investigated for their biomedical applications. The so-called applications necessitate the inclusion of these nanoparticles inside polymeric matrices (for example- dendrimer) leading to chemical functionalization of the metallic nanoparticles. Silver and silver nanoparticles' antibacterial activity has already been well established over years. Dendrimers due to their homogeneous highly branched structure and uniform composition are perfectly suitable for the inclusion of silver nanoparticles [Ag NPs]. Recently, the increasing trend in the development of Ag-dendrimer nanocomposites is attributed to the excellent antibacterial activity of Ag as well as dendrimer's unique properties like variable functional terminal ends and potential antibacterial effect necessarily. This review provides an informative overview regarding the numerous aspects of bactericidal and other biomedical applications of Ag-dendrimer nanocomposites, particularly emphasizing analysis of existing research and prospective worth to the pharmaceutical sector in future.

Antimicrobial resistance: Prevalence, economic burden, mechanisms of resistance and strategies to overcome

Antibiotic resistance is a major health concern globally and has been estimated to cause 10 million deaths worldwide by year 2050 if the current trend of inappropriate and excessive use of antibiotics continues. Although, the discovery of antibiotics has saved countless of lives for the past 80 years, increasing levels of bacterial resistance to antibiotics would jeopardize the progress in clinical and agricultural sectors and may cause life-threatening situations even for previously treatable bacterial infections. Antibiotic resistance would increase the levels of poverty of low-middle income countries mostly due to extended hospital stays, higher cost of treatment and untimely deaths that directly affect the total productivity rate. Recent incidences of antibiotic resistance have been gradually increasing globally and this may potentiate horizontal transmission of the resistant gene and have been linked with cross-resistance to other antibiotic families as well. This review summarizes the global burden of antibiotic resistance from the economic viewpoint, highlights the recent incidences of antibiotic resistance mainly related to Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Salmonella spp. and Staphylococcus aureus, describes the common mechanistic actions of antibiotic resistance and potential strategies to overcome antibiotic resistance.

The Effects of Thermal Pasteurisation, Freeze-Drying, and Gamma-Irradiation on the Antibacterial Properties of Donor Human Milk

The most common pasteurisation method used by human milk banks is Holder pasteurisation. This involves thermal processing, which can denature important proteins and can potentially reduce the natural antimicrobial properties found in human milk. This study assesses the application of a hybrid method comprised of freeze-drying followed by low-dose gamma-irradiation for nonthermal donor human milk pasteurisation. Freeze-drying donor human milk followed by gamma-irradiation at 2 kGy was as efficient as Holder pasteurisation in the reduction of bacterial inoculants of Staphylococcus aureus (10⁶ cfu/mL) and Salmonella typhimurium (10⁶ cfu/mL) in growth inhibition assays. These assays also demonstrated that human milk naturally inhibits the growth of bacterial inoculants S. aureus, S. typhimurium, and Escherichia coli. Freeze drying (without gamma-irradiation) did not significantly reduce this natural growth inhibition. By contrast, Holder pasteurisation significantly reduced the milk’s natural antimicrobial effect on S. aureus growth after 6 h (−19.8% p = 0.01). Freeze-dried and then gamma-irradiated donor human milk showed a strong antimicrobial effect across a dose range of 2–50 kGy, with only a minimal growth of S. aureus observed after 6 h incubation. Thus, a hybrid method of freeze-drying followed by 2 kGy of gamma-irradiation preserves antimicrobial properties and enables bulk pasteurisation within sealed packaging of powderised donor human milk. This work forwards a goal of increasing shelf life and simplifying storage and transportation, while also preserving functionality and antimicrobial properties.

A retrospective cross-sectional survey on nosocomial bacterial infections and their antimicrobial susceptibility patterns in hospitalized patients in northwest of Iran

Objective

Nosocomial infections (NIs) are known as one of the remarkable problems in all countries. This study is aimed to estimate the prevalence rate of nosocomial bacterial agents with antimicrobial susceptibility pattern in hospitalized patients. This study was conducted from April 2017 to September 2018, on 4029 hospitalized patients. We set out to recognize the commonest bacterial infections and antimicrobial susceptibility patterns of nosocomial infection.

Results

Of the 4029 patients, 509 (12.6%) of them were culture positive. Of these Escherichia coli (E. coli) (98.3%) and Staphylococcus epidermidis (S. epidermidis) (37.5%) were the most abundant bacterial identified in the urinary tract and bloodstream cultures respectively, Moreover, Acinetobacter spp. (100%) and Pseudomonas aeruginosa (22.2%) were the most abundant organisms detected in the respiratory system. According to susceptibility testing results, 370 (80.5%) and 264 (57.3%) in Gram-negatives and 44 (91.7%) and 35 (72.9%) in gram positives isolated strains were classified as multidrug-resistant (MDR) and extensive drug-resistant (XDR) strain respectively. On account of the high prevalence of MDR and XDR bacterial species, there is a pressing need for the expansion of new strategies on antibiotic supervision and infection control to introduce new guideline on empirical antibiotic therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05503-0.

Nosocomial Infections and Epidemiology of Antibiotic Resistance in Teaching Hospitals in South East of Iran

Aim:

Antibiotic resistance as one of the most serious health threats worldwide leading to a high rate of morbidity and mortality. The aim of present study was to examine the prevalence of nosocomial infections (NIs) and pattern of antibiotic resistance in teaching hospitals in Iran

Methods:

This cross-sectional descriptive study was conducted in a period of one year in three teaching hospitals and all patients with suspected NIs symptoms were chooses. Among these patients who showed antibiotic resistance were included in the study. The samples for clinical test in laboratory were obtained with using standard methods and aseptic technique by trained personnel. Antibiotic susceptibility testing was performed by Kirby-Bauer’s disk diffusion method on Muller-Hinton agar (Hi Media, Mumbai, India) in accordance with the standards of the Clinical Laboratory Standards Institute.

Results:

During one year study, 561 patients with nosocomial infections were recognized and among them 340 patients (60.6%) showed some level of antibiotic resistance. The most common cause of NIs in present study was Acinetobacter and the most type of infection was respiratory system infections (52.7%). The highest resistance rate was against Ciprofloxacin (61.8%) followed by Imipenem (50.3%).

Conclusion:

Rate of NIs and antibiotics resistance is high in Iranian hospital. So Iranian health ministry should provide guideline and suitable programs for prevention of NIs and antibiotic therapy in hospitals.

Antimicrobial properties of K alanchoe blossfeldiana: a focus on drug resistance with particular reference to quorum sensing-mediated bacterial biofilm formation

Objectives

This study attempts to investigate the antimicrobial properties of Kalanchoe blossfeldiana with a particular reference to quorum sensing (QS)-mediated biofilm formation.

Methods

The methanol extract of K. blossfeldiana leaves (MEKB) was evaluated for antimicrobial properties including QS-controlled production of biofilm (including virulence factor, motility and lactone formation) in Pseudomonas aeruginosa. Methanol extract of K. blossfeldiana was also evaluated for anti-cytokine (tumour necrosis factor-alpha, interleukin-6 and interleukin-1 beta) properties in peripheral blood mononuclear cells (PBMC).

Key findings

Methanol extract of K. blossfeldiana exhibited antimicrobial effect on clinical isolates, as well as standard reference strains. Pseudomonas aeruginosa exposed to MEKB (subminimum inhibitory concentration (MIC)) displayed reduced biofilm formation, whereas supra-MIC produced destruction of preformed biofilms. Methanol extract of K. blossfeldiana reduced the secretion of virulence factors (protease and pyoverdin) along with generation of acyl homoserine lactone (AHL). Confocal laser scanning microscopy images indicate reduction of biofilm thickness. The extract also reduced cytokine formation in lipopolysaccharide-stimulated PBMC.

Conclusions

K alanchoe blossfeldiana was found to interfere with AHL production, which in turn may be responsible for downregulating QS-mediated production of biofilm and virulence. This first report on the antibiofilm and anticytokine properties of this plant may open up new vistas for future exploration of this plant for combating biofilm-related resistant infections.

Network analysis suggests a potentially 'evil' alliance of opportunistic pathogens inhibited by a cooperative network in human milk bacterial communities

The critical importance of human milk to infants and even human civilization has been well established. Yet our understanding of the milk microbiome has been limited to cataloguing OTUs and computation of community diversity. To the best of our knowledge, there has been no report on the bacterial interactions within the milk microbiome. To bridge this gap, we reconstructed a milk bacterial community network based on Hunt et al. Our analysis revealed that the milk microbiome network consists of two disconnected sub-networks. One sub-network is a fully connected complete graph consisting of seven genera as nodes and all of its pair-wise interactions among the bacteria are facilitative or cooperative. In contrast, the interactions in the other sub-network of eight nodes are mixed but dominantly cooperative. Somewhat surprisingly, the only ‘non-cooperative' nodes in the second sub-network are mutually cooperative Staphylococcus and Corynebacterium that include some opportunistic pathogens. This potentially ‘evil' alliance between Staphylococcus and Corynebacterium could be inhibited by the remaining nodes that cooperate with one another in the second sub-network. We postulate that the ‘confrontation' between the ‘evil' alliance and ‘benign' alliance and the shifting balance between them may be responsible for dysbiosis of the milk microbiome that permits mastitis.

Impact of antibiotic exposure on occurrence of nosocomial carbapenem-resistant Acinetobacter baumannii infection: a case control study

Carbapenem-resistant Acinetobacter baumannii (CRAB) infection is one of the most important healthcare associated diseases worldwide. Although antibiotic use is recognized as a risk factor for CRAB infection, the impact of antibiotic class and length of use on CRAB infection is still unclear. A case-control study was conducted in adult intensive care units and general wards of Songklanagarind Hospital, a tertiary-care hospital in southern Thailand, to investigate the effect of different antibiotic exposure and the duration of use on the risk of developing CRAB infection. Cases were defined as patients with carbapenem-susceptible A. baumannii (CSAB) or CRAB infection. Controls were randomly selected from patients and matched 1:1 with cases using ward and date of admission. Multinomial logistic regression was used to compute relative risk ratios (RRR) and 95% confidence intervals (CI) for CRAB infection. Of 197 cases with A. baumannii infection, there were 139 with CRAB infection and 58 with CSAB infection. Compared to the control group, use of fluoroquinolones, broad-spectrum cephalosporins and carbapenems for more than three days increased the risk of CRAB infection with RRR (95% CI) of 81.2 (38.1-862.7), 31.3 (9.9-98.7) and 112.1 (7.1-1770.6), respectively. The RRR (95% CI) for one to three day treatment of fluoroquinolones, broad-spectrum cephalosporins and carbapenems were 5.4 (0.8-38.7), 6.2 (0.1-353.2) and 63.3 (15.6-256.9), respectively. Long-term use of certain antibiotics and even short term use of carbapenems increased the risk of CRAB infection. In this setting, use of these antibiotics, especially carbapenems, should be limited to reduce CRAB infection.

The impact of a "search and destroy" strategy for the prevention of methicillin-resistant Staphylococcus aureus infections in an inpatient rehabilitation facility

OBJECTIVE

To determine how the implementation of a methicillin-resistant Staphylococcus aureus (MRSA) control program in an inpatient rehabilitation facility (IRF) affects MRSA health care-associated infections (MRSA-HAIs).

DESIGN

A retrospective chart review.

SETTING

IRF affiliated with Vidant Medical Center, an 861-bed, acute-care teaching hospital for The Brody School of Medicine at East Carolina University.

PATIENTS

Seventy-nine adult patients in the IRF who developed a MRSA-HAI from February 2005 through January 2011.

INTERVENTIONS

Both the acute care hospital and the affiliated inpatient rehabilitation unit began screening 100% of admissions for MRSA nasal carriage, with decolonization of positive carriers, starting in February 2007.

MAIN OUTCOME MEASUREMENTS

Yearly rates of MRSA-HAI per 1000 patient-days were compared in the IRF before and after the intervention.

RESULTS

The weighted mean monthly infection rate before the intervention (February 2005 through January 2007) was 1.0714 per 1000 patient days compared with 0.6557 per 1000 patient days after the intervention (February 2007 through January 2011). The decreased infection rates after the intervention were statistically significant (P = .0315).

CONCLUSIONS

The implementation of an all-admissions MRSA screening program with decolonization of positive carriers in an IRF affiliated with an acute care hospital resulted in decreased MRSA-HAI rates in the IRF. When developing surveillance guidelines for MRSA, IRFs should be cognizant of infection rate trends and of the affiliated hospital's scope of policies and practices for infection prevention and control.

Where do hands go? An audit of sequential hand-touch events on a hospital ward

BACKGROUND

Reservoirs of pathogens could establish themselves at forgotten sites on a ward, posing a continued risk for transmission to patients via unwashed hands.

AIM

To track potential spread of organisms between surfaces and patients, and to gain a greater understanding into transmission pathways of pathogens during patient care.

METHODS

Hand-touch activities were audited covertly for 40 × 30 min sessions during summer and winter, and included hand hygiene on entry; contact with near-patient sites; patient contact; contact with clinical equipment; hand hygiene on exit; and contact with sites outside the room.

FINDINGS

There were 104 entries overall: 77 clinical staff (59 nurses; 18 doctors), 21 domestic staff, one pharmacist and five relatives. Hand-hygiene compliance among clinical staff before and after entry was 25% (38/154), with higher compliance during 20 summer periods [47%; 95% confidence interval (CI): 35.6-58.8] than during 20 winter periods (7%; 95% CI: 3.2-14.4; P < 0.0001). More than half of the staff (58%; 45/77) touched the patient. Staff were more likely to clean their hands prior to contact with a patient [odds ratio (OR): 3.44; 95% CI: 0.94-16.0); P = 0.059] and sites beside the patient (OR: 6.76; 95% CI: 1.40-65.77; P = 0.0067). Nearly half (48%; 37/77) handled patient notes and 25% touched the bed. Most frequently handled equipment inside the room were intravenous drip (30%) and blood pressure stand (13%), and computer (26%), notes trolley (23%) and telephone (21%) outside the room.

CONCLUSION

Hand-hygiene compliance remains poor during covert observation; understanding the most frequent interactions between hands and surfaces could target sites for cleaning.

Effectiveness and feasibility of using a physical barrier device in reducing rates of microbial contamination of sphygmomanometer cuffs

phygmomanometers are frequently contaminated with bacteria and are implicated in the transmission of microbes. A pilot study was conducted to determine the effectiveness and feasibility of using a physical barrier device in reducing rates of microbial contamination of sphygmomanometer cuffs. Blood pressure recordings were made with and without a disposable plastic device on healthy individuals to ensure that it did not interfere with the accuracy of readings. Baseline rates of microbial colonisation of sphygmomanometer cuffs were obtained over a six week period. For six weeks the device was applied to patients’ arms before measuring blood pressure, and sphygmomanometer cuffs were recultured during the intervention period. No difference was found in blood pressure recordings with and without the device. No difference in rates of bacterial contamination was observed during the intervention phase of the study. A disposable plastic device acting as a physical barrier may not reduce surface contamination of sphygmomanometer cuffs.

Isolation and identification of microbes associated with mobile phones in Dammam in eastern Saudi Arabia

OBJECTIVE

This study was conducted to determine microbial contamination of mobile phones in the city of Dammam, in the eastern region of Saudi Arabia, and identify the most important microbial species associated with these phones in order to take the necessary remedial measures.

MATERIALS AND METHODS

The analysis of a total of 202 samples was done to identify fungal and pathogenic bacteria isolates. Sterile swabs were firmly passed on the handset, the buttons and the screens of mobile phones, then inoculated into media of bacteria and fungi. Frequency distribution of isolates were calculated.

RESULTS

There were 737 isolated of the following bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Neisseria sicca, Micrococcus luteus, Proteus mirabilis, Bacillus subtilis, and Enterobacter aerogenes at the rate of 56.58, 13.57, 8.01, 7.73, 6.51, 3.66, 2.85 and 1.09% respectively. There were fungal isolates as follows: Alternaria alternata, Aspergillus niger, Cladosporium sp., Penicillium spp., Aspergillus flavus, Aspergillus fumigatus, Rhizopus stolonifer, Aspergillus ochraceus at the rate of 29.07, 26.74, 20.93, 10.47, 6.98, 2.33, 2.33, 1.16%, respectively.

CONCLUSIONS

The study showed that all mobile phones under consideration were infected by several microbes, most of which belonged to the natural flora of the human body as well as airborne fungi and soil. This means that it is necessary to sterilize hands after contact with a phone since it is a source of disease transmission.

Epidemiology and control of an outbreak of vancomycin-resistant enterococci in the intensive care units

PURPOSE

This study was aimed to describe a vancomycin-resistant enterococci (VRE) outbreak across three intensive care units (ICUs) of a Korean hospital from September 2006 to January 2007 and the subsequent control strategies.

MATERIALS AND METHODS

We simultaneously implemented multifaceted interventions to control the outbreak, including establishing a VRE cohort ward, active rectal surveillance cultures, daily extensive cleaning of environmental surfaces and environmental cultures, antibiotic restriction, and education of hospital staff. We measured weekly VRE prevalence and rectal acquisition rates and characterized the VRE isolates by polymerase chain reaction (PCR) of the vanA gene and Sma1-pulsed-field gel electrophoresis (PFGE).

RESULTS

During the outbreak, a total of 50 patients infected with VRE were identified by clinical and surveillance cultures, and 46 had vancomycin-resistant Enterococcus faecium (VREF). PFGE analysis of VREF isolates from initial two months disclosed 6 types and clusters of two major types. The outbreak was terminated 5 months after implementation of the interventions: The weekly prevalence rate decreased from 9.1/100 patients-day in September 2006 to 0.6/100 by the end of January 2007, and the rectal acquisition rates also dropped from 6.9/100 to 0/100 patients-day.

CONCLUSION

Our study suggests that an aggressive multifaceted control strategy is a rapid, effective approach for controlling a VRE outbreak.

Implementing the MRSA recommendations made by the Commission for Hospital Hygiene and Infection Prevention (KRINKO) of 1999 - current considerations by the DGKH Management Board

In Germany, recommendations on dealing with patients who are colonised with methicillin-resistant S. aureus (MRSA) for the inpatient sector have been published in 1999 by the Commission for Hospital Hygiene and Infection Prevention (KRINKO). Some challenges arise with regard to the practical implementation of the KRINKO recommendations. These challenges do not principally question the benefit of the recommendations but have come into criticism from users. In this commentary the German Society for Hospital Hygiene (DGKH) discusses some controversial issues and adds suggestions for unresolved problems regarding the infection control management of MRSA in healthcare settings.

Prevalence of methicillin-resistant Staphylococcus aureus among orthopedic patients at a large academic hospital

Community-based methicillin-resistant Staphylococcus aureus (MRSA) contributes to postoperative surgical site infections, and it is therefore important to eliminate nasal carriage of MRSA before surgery. A total of 678 nasal swabs were performed on elective orthopedic patients undergoing surgery with the usage of metal implants. Thirty-eight specimens (5.6%) were positive for MRSA and 146 (21.5%) were positive for methicillin-sensitive S aureus (MSSA). A slow increase in the number of MSSA was noted between 2006 and 2007. Positive cases of MRSA nasal carriage were treated with nasal mupirocin ointment and chlorhexidine baths or showers for 5 days prior to surgery.

Modeling antibiotic resistance in hospitals: the impact of minimizing treatment duration

Infections caused by antibiotic-resistant pathogens are a global public health problem. Numerous individual- and population-level factors contribute to the emergence and spread of these pathogens. An individual-based model (IBM), formulated as a system of stochastically determined events, was developed to describe the complexities of the transmission dynamics of antibiotic-resistant bacteria. To simplify the interpretation and application of the model's conclusions, a corresponding deterministic model was created, which describes the average behavior of the IBM over a large number of simulations. The integration of these two model systems provides a quantitative analysis of the emergence and spread of antibiotic-resistant bacteria, and demonstrates that early initiation of treatment and minimization of its duration mitigates antibiotic resistance epidemics in hospitals.

A new microbiological problem in intensive care units: environmental contamination by MRSA with reduced susceptibility to glycopeptides

The present study evaluated the percentage of methicillin-resistant Staphylococcus aureus strains with reduced susceptibility to glycopeptides in four intensive care units (ICU) by means of environmental sampling of air and representative surfaces. The total bacterial count was taken and possible S. aureus strains were subsequently isolated. To assess methicillin resistance, an antibiogram was performed on the colonies that were positive to the coagulase test. A standard E-test was then carried out on the colonies that developed, in order to evaluate glycopeptide resistance, and any heterogeneous resistance was confirmed by means of a macromethod E-test. The antibiogram performed on the colonies of S. aureus revealed that 85.7% of all air samples were positive for MRSA, and that 64.3% of all the samples proved to be heterogeneously resistant to glycopeptides. Methicillin resistance was recorded in 41.0% of surface samples, and 32.5% of all samples proved positive for hGISA.

Inhibitory impact of bifidobacteria on the transfer of beta-lactam resistance among Enterobacteriaceae in the gnotobiotic mouse digestive tract

While looking for new means to limit the dissemination of antibiotic resistance, we evaluated the role of potentially probiotic bifidobacteria on the transfer of resistance genes between enterobacteria. Transfers of bla genes encoding extended-spectrum beta-lactamases (SHV-5 and CTX-M-15) were studied in the absence or presence of bifidobacteria. In vitro, transfer frequencies of these bla genes decreased significantly in the presence of three of five tested strains, i.e., Bifidobacterium longum CUETM-89-215, Bifidobacterium bifidum CIP-56.7T, and Bifidobacterium pseudocatenulatum CIP-104168T. Four transfer experiments were conducted in the digestive tract of gnotobiotic mice, the first three observing the effect of B. longum CUETM-89-215, B. bifidum CIP-56.7T, and B. pseudocatenulatum CIP-104168T on blaSHV-5 transfer and the fourth experiment studying the effect of B. bifidum CIP-56.7T on blaCTX-M-15 transfer. These experiments revealed significant decreases in the transconjugant levels (up to 3 logs) in mice having received B. bifidum CIP-56.7T or B. pseudocatenulatum CIP-104168T compared to control mice. Bifidobacteria appear to have an inhibitory impact on the transfer of antibiotic resistance genes. The inhibitory effect is associated to specific bifidobacterial strains and may be related to the production of thermostable metabolites by these strains.

The fallacies of hope: will we discover new antibiotics to combat pathogenic bacteria in time?

While newly developed technologies have revolutionized the classical approaches to combating infectious diseases, the difficulties associated with developing novel antimicrobials mean that these technologies have not yet been used to introduce new compounds into the market. The new technologies, including genomics and structural biology, open up exciting possibilities for the discovery of antibiotics. However, a substantial effort to pursue research, and moreover to incorporate the results into the production chain, is required in order to bring new antimicrobials to the final user. In the current scenario of emerging diseases and the rapid spread of antibiotic resistance, an active policy to support these requirements is vital. Otherwise, many valuable programmes may never be fully developed for lack of "interest" and funds (private and public). Will we react in time to avoid potential disaster?

An evaluation of patient area cleaning in 3 hospitals using a novel targeting methodology

BACKGROUND

Although environmental cleaning and disinfecting practices have become a cornerstone of patient care, assessment of actual compliance with such procedures has not been reported. Using a novel methodology, we developed a means to monitor directly such activities.

METHODS

A nontoxic target solution, which intensely fluoresces with a black light, was formulated to be inconspicuous yet readily removed by housekeeping products. Small volumes of material were confidentially applied to 12 target sites in patient rooms in 3 hospitals following terminal cleaning. The targets were reevaluated following terminal cleaning after several patients had occupied the room.

RESULTS

One hundred fifty-seven rooms and 1404 targets were evaluated. In the 3 hospitals studied, only 45%, 42%, and 56% of targets were removed by routine terminal cleaning/disinfecting activities. The frequency with which various individual sites were cleaned varied widely but was similar in all hospitals.

CONCLUSION

The use of a novel target compound to evaluate housekeeping practices confirmed high rates of cleaning of traditional sites but poor cleaning of many sites that have significant potential for harboring and transmitting microbial pathogens. This methodology has the potential for being used to evaluate objectively the cleaning/disinfecting activities in various health care settings.

Knowledge, attitude, and practices related to standard precautions of surgeons and physicians in university-affiliated hospitals of Shiraz, Iran

OBJECTIVE

To measure levels of knowledge, attitudes, and practice toward standard precautions (SP) in medical practitioners of Shiraz University of Medical Sciences affiliated hospitals in Iran.

METHOD

In this cross-sectional study, knowledge, attitude, and practice related to SP among four medical staff groups - surgeons, surgical residents, physicians and medical residents - were assessed using a questionnaire.

RESULTS

Across the four medical staffing groups the median levels of knowledge ranged from 6 to 7 (maximum score 9), median attitude scores were high ranging from 35 to 36 (maximum score 45), while median practice scores were low, ranging from 2 to 3 (maximum score 9). A moderate relationship between knowledge and attitudes was found in surgical residents and medical residents (r=0.397, p=0.030 and r=0.554, p=0.006, respectively). No significant correlation was found between knowledge and practice between the groups. A significant but poor (r=0.399, p=0.029) relationship between attitude and practice was found in surgical residents.

CONCLUSION

Specific training programs may have to target newly graduated medical practitioners to establish acceptance of appropriate practices that will enable them to adopt and adhere to SP while their older counterparts may require more intense continuous assistance.

Effect of targeted surveillance for control of methicillin-resistant Staphylococcus aureus in a community hospital system

OBJECTIVE

To examine the cost associated with targeted surveillance for methicillin-resistant Staphylococcus aureus (MRSA) and the effect of such surveillance on the rate of nosocomial MRSA infection in a community hospital system.

DESIGN

A before-and-after study comparing the rate of MRSA infection before (BES) and after (AES) the initiation of expanded surveillance. Cost-effectiveness was calculated as the difference between the cost savings associated with preventing nosocomial MRSA bacteremias and surgical site infections AES and the cost of MRSA cultures and contact isolation for patients colonized with MRSA.

SETTING AND PARTICIPANTS

Patients in a 400-bed tertiary-care facility (Roper Hospital) and a 180-bed suburban hospital (St. Francis Hospital), both in Charleston, South Carolina.Interventions. Beginning in September 2001, patients were screened for MRSA colonization upon admission to the intensive care unit and weekly thereafter. In July 2002, surveillance was expanded to include targeted screening of patients admitted to general wards who were at risk of MRSA colonization. Colonized patients were placed in contact isolation.

RESULTS

The mean rate of nosocomial MRSA infection decreased at Roper (0.76 cases per 1,000 patient-days BES and 0.45 per 1000 patient-days AES; P = .05) and at St. Francis (0.73 cases per 1,000 patient-days BES and 0.57 cases per 1000 patient-days AES; P=.35). Surveillance was cost-effective, preventing 13 nosocomial MRSA bacteremias and 9 surgical site infections, for a savings of 1,545,762 US dollars.

CONCLUSIONS

Targeted surveillance for MRSA colonization was cost-effective and provided substantial benefits by reducing the rate of nosocomial MRSA infections in a community hospital system.

Colonization of personal digital assistants used in a health care setting

BACKGROUND

The use of personal digital assistants (PDAs) by health care workers is increasing. Increasing rates of infection in our institution led to the question of whether PDAs were colonized with pathogenic organisms.

METHODS

Specimens for culture were obtained from PDAs used at our institution, and surveys were distributed to the users to determine factors predisposing to colonization.

RESULTS

Forty percent of PDAs had growth on culture. The most common organism detected on 27 of 82 PDAs was coagulase-negative Staphylococcus (82%). No isolates of methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci were detected. Colonization was more common on PDAs that had undergone previous cleaning. No other predisposing factors to colonization were found.

CONCLUSIONS

PDAs are frequently colonized with typical skin organisms and less commonly with pathogenic organisms. Whether PDAs used in the health care setting serve as vectors for nosocomial infection is not determined.

Impact of screening for MRSA carriers at hospital admission on risk-adjusted indicators according to the imported MRSA colonization pressure

We evaluated the impact of the different components of a screening programme of methicillin-resistant Staphylococcus aureus (MRSA) carriers at hospital admission on the value of two risk-adjusted rates: the proportion of imported MRSA and an indicator of the MRSA colonization pressure (ICP), and the incidence of MRSA acquired and detected in our hospital. Indicators were calculated: (1) with no screening programme; (2) with a programme limited to the intensive care unit (ICU); (3) with a programme extended to patients with risk factors for MRSA carriage hospitalized in non-ICU wards. The programme included an automatic alert. Systematic sampling of patients with risk factors hospitalized in non-ICU settings detected nearly 50% of carriers at admission. The proportion of MRSA imported into our hospital varied from 35.4% without any screening programme to 71.8% when all components of our screening programme were considered (P<10(-4)). The ICP varied from 3.1% (31/985) with the complete programme to 10.4% (31/297) without any screening programme (P<10(-6)). Screening patients with risk factors for MRSA carriage hospitalized in non-ICU wards resulted in a 51% increase of the calculated proportion of imported strains and a 58% decrease of the ICP. The two studied indicators were strongly dependent on the screening strategy for MRSA carriers implemented at admission. The screening strategy for patients admitted to non-ICU wards who have risk factors for MRSA carriage seems to be the determinant for the interpretation of certain risk-adjusted indicators of MRSA cross-transmission. Comparisons of these indicators must consider the setting in which the screening programmes are implemented.

Controlled Trials to Improve Antibiotic Utilization: A Systematic Review of Experience, 1984–2004

STUDY OBJECTIVES

To review the effectiveness of interventions designed to improve antibiotic prescribing patterns in clinical practice and to draw inferences about the most practical methods for optimizing antibiotic utilization in hospital and ambulatory settings.

METHODS

A literature search using online databases for the years 1975-2004 identified controlled trials of strategies for improving antibiotic utilization. Due to variation in study settings and design, quantitative meta-analysis was not feasible. Therefore, a qualitative literature review was conducted.

RESULTS

Forty-one controlled trials met the search criteria. Interventions consisted of education, peer review and feedback, physician participation, rewards and penalties, administrative methods, and combined approaches. Social marketing directed at patients and prescribers was effective in varying contexts, as was implementation of practice guidelines. Authorization systems with structured order entry, formulary restriction, and mandatory consultation were also effective. Peer review and feedback were more effective when combined with dissemination of relevant information or social marketing than when used alone.

CONCLUSIONS

Several practices were effective in improving antibiotic utilization: social marketing, practice guidelines, authorization systems, and peer review and feedback. Online systems providing clinical information, structured order entry, and decision support may be the most promising approach. Further studies, including economic analyses, are needed to confirm or refute this hypothesis.

Impact of implementing a method of feedback and accountability related to contact precautions compliance

BACKGROUND

In January 2002, Infection control professionals for Spartanburg Regional Healthcare System held a planning retreat focused on patient safety. The main challenge discussed was the control of antibiotic-resistant organisms. Rounds on the patient care units had revealed compliance issues with the current isolation procedures. The team developed a process improvement project coined the Effective Processes in Infection Control Project (EPIC). With a broad challenge of antibiotic resistance, the focus was narrowed to isolation precautions for methicillin-resistant Staphylococcus aureus (MRSA).

METHODS

The initial stage of the EPIC project was education, followed by routine unit rounds to monitor compliance. A tool was developed to provide immediate feedback for the nursing units. Summary reports were generated for clinical directors as a method of accountability for unit leadership. Rates for facility-acquired MRSA were monitored and compared with MRSA days at risk.

RESULTS

Over a 1-year period of increased accountability, the facility-acquired rate of MRSA decreased by 30%, even though the days at risk increased. The decrease was maintained during year 2.

CONCLUSIONS

The results of this project point to the importance of accountability with isolation precautions in the effort to combat the spread of MRSA in the hospital setting.

Isolation measures in the hospital management of methicillin resistant Staphylococcus aureus (MRSA): systematic review of the literature

OBJECTIVE

To evaluate the evidence for the effectiveness of isolation measures in reducing the incidence of methicillin resistant Staphylococcus aureus (MRSA) colonisation and infection in hospital inpatients.

DESIGN

Systematic review of published articles.

DATA SOURCES

Medline, Embase, CINAHL, Cochrane Library, System for Information on Grey Literature in Europe (SIGLE), and citation lists (1966-2000).

REVIEW METHODS

Articles reporting MRSA related outcomes and describing an isolation policy were selected. No quality restrictions were imposed on studies using isolation wards or nurse cohorting. Other studies were included if they were prospective or employed planned comparisons of retrospective data.

RESULTS

46 studies were accepted; 18 used isolation wards, nine used nurse cohorting, and 19 used other isolation policies. Most were interrupted time series, with few planned formal prospective studies. All but one reported multiple interventions. Consideration of potential confounders, measures to prevent bias, and appropriate statistical analysis were mostly lacking. No conclusions could be drawn in a third of studies. Most others provided evidence consistent with a reduction of MRSA acquisition. Six long interrupted time series provided the strongest evidence. Four of these provided evidence that intensive control measures including patient isolation were effective in controlling MRSA. In two others, isolation wards failed to prevent endemic MRSA.

CONCLUSION

Major methodological weaknesses and inadequate reporting in published research mean that many plausible alternative explanations for reductions in MRSA acquisition associated with interventions cannot be excluded. No well designed studies exist that allow the role of isolation measures alone to be assessed. None the less, there is evidence that concerted efforts that include isolation can reduce MRSA even in endemic settings. Current isolation measures recommended in national guidelines should continue to be applied until further research establishes otherwise.

Control of endemic MRSA-what is the evidence? A personal view

Although there is extensive literature on the control of MRSA, when that concerning epidemics is excluded, only a limited amount remains regarding the control of endemic MRSA. Several guidelines have been recently published recommending stringent control measures, which are often suggested based on their success in controlling MRSA outbreaks in hospitals with few MRSA or in containing MRSA cases introduced into a hospital with no MRSA. In these settings, multiple measures are usually introduced with apparently successful results. However, results may not be generalizable to other settings and we do not know the minimum effective measures required for MRSA containment. This paper aims critically to review the literature to determine whether evidence exists for the value of the infection control measures that are widely recommended in the endemic setting. Much of this literature is based on observational studies, with few randomized, controlled trials having been conducted. More well-designed studies are required before many of the principles on which we build infection control programmes can be regarded as evidence based.

Assessing the status of infection control programs in small rural hospitals in the western United States

BACKGROUND

Organized infection control (IC) interventions have been successful in reducing the acquisition of hospital-associated infections. Rural community hospitals, although contributing significantly to the US health care system, have rarely been assessed regarding the nature and quality of their IC programs.

METHODS

A sample of 77 small rural hospitals in Idaho, Nevada, Utah, and eastern Washington completed a written survey in 2000 regarding IC staffing, infrastructure support, surveillance of nosocomial infections, and IC policies and practices.

RESULTS

Almost all hospitals (65 of 67, 97%) had one infection control practitioner (ICP), and 29 of 61 hospitals (47.5%) reported a designated physician with IC oversight. Most ICPs (62 of 64, 96.9%) were also employed for other activities outside of IC. The median number of ICP hours per week for IC activities was 10 (1-40), equating to a median of 1.56 (0.30-21.9) full-time ICPs per 250 hospital beds. Most hospitals performed total house surveillance for nosocomial infections (66 of 73, 90.4%) utilizing Centers for Disease Control and Prevention (CDC) definitions (69 of 74, 93.2%). Most also monitored employee bloodborne exposures (69 of 73, 94.5%). All hospitals had a written bloodborne pathogen exposure plan and isolation policies. CDC guidelines were typically followed when developing IC policies. Access to medical literature and online resources appeared to be limited for many ICPs.

CONCLUSIONS

Most rural hospitals surveyed have expended reasonable resources to develop IC programs that are patterned after those seen in larger hospitals and conform to recommendations of consensus expert panels. Given these hospitals' small patient census, short length of stay, and low infection rates, further studies are needed to evaluate necessary components of effective IC programs in these settings that efficiently utilize limited resources without compromising patient care.

Strategic use of antibiotics in the neonatal intensive care unit

Infection is one of the most common causes of infant morbidity and mortality in the neonatal intensive care unit, despite the availability of various therapeutic medical interventions, such as mechanical ventilation, that allow premature infants a better chance of survival. In fact, many of these therapeutic interventions violate the natural protective barriers for infection. Fortunately, maternal and neonatal risk factors have been identified for early- and late-onset sepsis and the prevalence of highly suspected pathogens for each type of infection influences the empiric selection of antibiotics. In many institutions, the common pathogens have developed resistance to antibiotics. In others, the predominance of pathogens has shifted. Both challenges may warrant modification of traditional antibiotic regimens. Continual monitoring of pathogen shifts within an individual neonatal intensive care unit and application of various antibiotic characteristics are key elements of strategic, safe, and effective use of antibiotics in this patient population. Development of a protocol incorporating infection control measures and guidelines for judicious use of antibiotics can minimize the threat of antibiotic resistance.

Pro/con clinical debate: isolation precautions for all intensive care unit patients with methicillin-resistant Staphylococcus aureus colonization are essential

Antibiotic-resistant bacteria are an increasingly common problem in intensive care units (ICUs), and they are capable of impacting on patient outcome, the ICU's budget and bed availability. This issue, coupled with recent outbreaks of illnesses that pose a direct risk to ICU staff (such as SARS [severe acute respiratory syndrome]), has led to renewed emphasis on infection control measures and practitioners in the ICU. Infection control measures frequently cause clinicians to practice in a more time consuming way. As a result it is not surprising that ensuring compliance with these measures is not always easy, particularly when their benefit is not immediately obvious. In this issue of Critical Care, two experts face off over the need to isolate patients infected with methicillin-resistant Staphylococcus aureus.

Inhibition of Staphylococcus aureus by the commensal bacteria of human milk

AIMS

To study the bacterial diversity in expressed human milk with a focus on detecting bacteria with an antimicrobial activity against Staphylococcus aureus, known as a causative agent of maternal breast infections and neonatal infections.

METHODS AND RESULTS

Random isolates (n = 509) were collected from breast milk samples (n = 40) of healthy lactating women, genotypically identified, and tested for antimicrobial activity against Staph. aureus. Commensal staphylococci (64%) and oral streptococci (30%), with Staph. epidermidis, Strep. salivarius, and Strep. mitis as the most frequent isolates, were the predominant bacterial species in breast milk. One-fifth of Staph. epidermidis and half of Strep. salivarius isolates suppressed growth of Staph. aureus. Enterococci (Ent. faecalis), isolated from 7.5% of samples, and lactic acid bacteria (LAB) (Lactobacillus rhamnosus, Lact. crispatus, Lactococcus lactis, Leuconoctoc mesenteroides), isolated from 12.5% of samples, were also effective against Staph. aureus. One L. lactis isolate was shown to produce nisin, a bacteriocin used in food industry to prevent bacterial pathogens and spoilage.

CONCLUSIONS

Expressed breast milk contains commensal bacteria, which inhibit Staph. aureus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The strains inhibitory against the pathogen Staph. aureus have potential use as bacteriotherapeutic agents in preventing neonatal and maternal breast infections caused by this bacterium.

SHEA guideline for preventing nosocomial transmission of multidrug-resistant strains of Staphylococcus aureus and enterococcus

BACKGROUND

Infection control programs were created three decades ago to control antibiotic-resistant healthcare-associated infections, but there has been little evidence of control in most facilities. After long, steady increases of MRSA and VRE infections in NNIS System hospitals, the Society for Healthcare Epidemiology of America (SHEA) Board of Directors made reducing antibiotic-resistant infections a strategic SHEA goal in January 2000. After 2 more years without improvement, a SHEA task force was appointed to draft this evidence-based guideline on preventing nosocomial transmission of such pathogens, focusing on the two considered most out of control: MRSA and VRE.

METHODS

Medline searches were conducted spanning 1966 to 2002. Pertinent abstracts of unpublished studies providing sufficient data were included.

RESULTS

Frequent antibiotic therapy in healthcare settings provides a selective advantage for resistant flora, but patients with MRSA or VRE usually acquire it via spread. The CDC has long-recommended contact precautions for patients colonized or infected with such pathogens. Most facilities have required this as policy, but have not actively identified colonized patients with surveillance cultures, leaving most colonized patients undetected and unisolated. Many studies have shown control of endemic and/or epidemic MRSA and VRE infections using surveillance cultures and contact precautions, demonstrating consistency of evidence, high strength of association, reversibility, a dose gradient, and specificity for control with this approach. Adjunctive control measures are also discussed.

CONCLUSION

Active surveillance cultures are essential to identify the reservoir for spread of MRSA and VRE infections and make control possible using the CDC's long-recommended contact precautions.

Market analysis of biosensors for food safety

This paper is presented as an overview of the pathogen detection industry. The review includes pathogen detection markets and their prospects for the future. Potential markets include the medical, military, food, and environmental industries. Those industries combined have a market size of $563 million for pathogen detecting biosensors and are expected to grow at a compounded annual growth rate of 4.5%. The food market is further segmented into different food product industries. The overall food-pathogen testing market is expected to grow to $192 million and 34 million tests by 2005. The trend in pathogen testing emphasizes the need to commercialize biosensors for the food safety industry as legislation creates new standards for microbial monitoring. With quicker detection time and reusable features, biosensors will be important to those interested in real time diagnostics of disease causing pathogens. As the world becomes more concerned with safe food and water supply, the demand for rapid detecting biosensors will only increase.

Production of the glycopeptide antibiotic A40926 by Nonomuraea sp. ATCC 39727: influence of medium composition in batch fermentation

Nonomuraea sp. ATCC 39727 is a novel actinomycete species and the producer of A40926, a glycopeptide antibiotic structurally similar to teichoplanin. In the present study, a defined minimal medium was designed for Nonomuraea fermentation. The influence of initial phosphate, glucose and ammonium concentrations on antibiotic productivity was investigated in batch fermentation and the effect of glucose limitation was studied in fed-batch fermentation. It was found that low initial concentrations of phosphate and ammonium are beneficial for A40926 production and that productivity is not enhanced during glucose limitation. Furthermore, the initiation of A40926 production was not governed by residual ammonium and phosphate concentrations, although the level of these nutrients strongly influenced A40926 production rates and final titers.

Large variation in MRSA policies, procedures and prevalence in English intensive care units: a questionnaire analysis

OBJECTIVE

Methicillin-resistant Staphylococcus aureus (MRSA) is a major problem in intensive care units in most countries. Despite recommendations for screening and isolation of patients with MRSA our perception has been that there is little uniformity in approach in ICUs besides adherence to basic infection control procedures. We thus sought to identify MRSA prevalence and the variation of infection control policy across intensive care units in England.

DESIGN AND SETTING

Postal questionnaire with telephone follow-up in English intensive care units.

MEASUREMENTS AND RESULTS

Responses were obtained from 217 (96%) ICUs. Marked variation in practice was noted in terms of patient screening, staff screening, infection control procedures, isolation or cohorting of colonised/infected patients, and ward discharge policy. Point prevalence data showed that 16.2% of ICU patients were known to be colonised or infected with MRSA. There was a regional bias, but no difference was noted between high and low prevalence regions in terms of unit demographics or infection control policies.

CONCLUSIONS

This study highlights the lack of consistent policy across English ICUs regarding isolation, screening and discharge practices for MRSA. Prospective studies are urgently needed to determine best practice.

Current implications of drug resistance in spinal cord injury

A 54-yr-old man with C6 quadriplegia and a neurogenic bowel and bladder was evaluated for clearance of a urinary tract infection after treatment for organisms susceptible to the antibiotics used, and an organism resistant to all antibiotics on the panel grew on the initial follow-up urine culture. Multidrug-resistant organisms present increasing challenges and risks in the management of the neurogenic bladder in patients with spinal cord injury. In an effort to control and reduce the impact and risk associated with these organisms, management methods of the neurogenic bladder and infection control policies should be adjusted according to guidelines from the Centers for Disease Control and related research; such policies could include surveillance for multidrug-resistant organisms and isolation of patients who test positive for these organisms.

Antimicrobial Use and Resistance

As antimicrobial use continues to rise, we are experiencing a concomitant rise in the prevalence of antimicrobial resistance. The precise relationship between use and resistance, however, has been challenging to define. Although the selection pressure exerted by antibiotic therapy appears to be the primary force promoting resistance, it is clear that the pathway to resistance is different for various organisms and antimicrobial agents. By understanding the mechanisms by which resistance emerges and spreads, it should be possible to design intervention strategies to slow or halt the process. This review summarizes some of our current understandings about the development and transmission of antibiotic-resistant bacteria, some of the control measures designed to interrupt the process, and how mathematical modeling can help us to better understand these complex pathways.