Antimicrobial resistance in intensive care units

Bridging Molecular and Clinical Sciences to Achieve the Best Treatment of Enterococcus faecalis Endocarditis

Enterococcus faecalis (E. faecalis) is a commensal bacterium that causes various infections in surgical sites, the urinary tract, and blood. The bacterium is becoming a significant concern because it tends to affect the elderly population, which has a high prevalence of undiagnosed degenerative valvular disease and is often subjected to invasive procedures and implanted medical devices. The bacterium's actions are influenced by specific characteristics like pili activity and biofilm formation. This resistance significantly impedes the effectiveness of numerous antibiotic therapies, particularly in cases of endocarditis. While current guidelines recommend antimicrobial therapy, the emergence of resistant strains has introduced complexity in managing these patients, especially with the increasing use of transcatheter therapies for those who are not suitable for surgery. Presentations of the condition are often varied and associated with generalised symptoms, which may pose a diagnostic challenge. We share our encounter with a case study that concerns an octogenarian who had a TAVI valve and developed endocarditis. We also conducted a literature review to identify the essential treatment algorithms for such cases.

A Literature Review on the Use of Aortic Allografts in Modern Cardiac Surgery for the Treatment of Infective Endocarditis: Is There Clear Evidence or Is It Merely a Perception?

Infective valve endocarditis is caused by different pathogens and 60% of those involve the aortic valve with valve failure. Although S. aureus is recognized as the most frequently isolated causative bacterium associated with IE in high-income countries, Gram-positive cocci nevertheless play a crucial role in promoting infection in relation to their adhesive matrix molecules. The presence of pili on the surface of Gram-positive bacteria such as in different strains of Enterococcus faecalis and Streptococcus spp., grants these causative pathogens a great offensive capacity due to the formation of biofilms and resistance to antibiotics. The indications and timing of surgery in endocarditis are debated as well as the choice of the ideal valve substitute to replace the diseased valve(s) when repair is not possible. We reviewed the literature and elaborated a systematic approach to endocarditis management based on clinical, microbiological, and anatomopathological variables known to affect postoperative outcomes with the aim to stratify the patients and orient decision making. From this review emerges significant findings on the risk of infection in the allograft used in patients with endocarditis and no endocarditis etiology suggesting that the use of allografts has proved safety and effectiveness in patients with both pathologies.

Dimensionality reduction and ensemble of LSTMs for antimicrobial resistance prediction

Bacterial resistance to antibiotics has been rapidly increasing, resulting in low antibiotic effectiveness even treating common infections. The presence of resistant pathogens in environments such as a hospital Intensive Care Unit (ICU) exacerbates the critical admission-acquired infections. This work focuses on the prediction of antibiotic resistance in Pseudomonas aeruginosa nosocomial infections at the ICU, using Long Short-Term Memory (LSTM) artificial neural networks as the predictive method. The analyzed data were extracted from the Electronic Health Records (EHR) of patients admitted to the University Hospital of Fuenlabrada from 2004 to 2019 and were modeled as Multivariate Time Series. A data-driven dimensionality reduction method is built by adapting three feature importance techniques from the literature to the considered data and proposing an algorithm for selecting the most appropriate number of features. This is done using LSTM sequential capabilities so that the temporal aspect of features is taken into account. Furthermore, an ensemble of LSTMs is used to reduce the variance in performance. Our results indicate that the patient's admission information, the antibiotics administered during the ICU stay, and the previous antimicrobial resistance are the most important risk factors. Compared to other conventional dimensionality reduction schemes, our approach is able to improve performance while reducing the number of features for most of the experiments. In essence, the proposed framework achieve, in a computationally cost-efficient manner, promising results for supporting decisions in this clinical task, characterized by high dimensionality, data scarcity, and concept drift.

Bacterial Adhesion and Biofilm Formation of Enterococcus faecalis on Zwitterionic Methylmethacrylat and Polysulfones

Biofilm-associated implant infections represent a major challenge for healthcare systems around the world due to high patient burden and enormous costs incurred. Enterococcus faecalis (E. faecalis) is the most prevalent enterococcal species identified in biofilm-associated infections. The steadily growing areas of application of implants demand a solution for the control of bacterial infections. Therefore, the development of modified anti-microbial implant materials and the testing of the behavior of different relevant bacterial strains towards them display an indispensable task. Recently, we demonstrated an anti-microbial effect of zwitterionic modified silicone rubber (LSR) against Staphylococcus aureus. The aim of this study was to evaluate bacterial colonization and biofilm formation of another clinically relevant strain, E. faecalis, on this material in comparison to two of the most commonly used thermoplastic polyurethanes (TPUs) and other modified LSR surfaces. By generating growth curves, crystal violet, and fluorescence staining, as well as analyzing the expression of biofilm-associated genes, we demonstrated no anti-microbial activity of the investigated materials against E. faecalis. These results point to the fact that anti-microbial effects of novel implant materials do not always apply across the board to all bacterial strains.

Clinical prediction tool for extended-spectrum beta-lactamase-producing enterobacterales as the etiology of a bloodstream infection in solid organ transplant recipients

BACKGROUND

Multidrug-resistant Gram-negative bacterial infections are increasingly common among solid organ transplant (SOT) recipients, leading to challenges in the selection of empiric antimicrobial therapy. We sought to develop a clinical tool to predict which SOT recipients are at high risk for extended-spectrum beta-lactamase (ESBL)-producing Enterobacterales (EB) bloodstream infection (BSI).

METHODS

A multicenter case-control study was performed. The source population included SOT recipients with an EB BSI between 2005 and 2018. Cases were those with ESBL-EB BSI; controls were those with non-ESBL EB BSI. The population was subdivided into derivation and validation cohorts based on study site. The predictive tool was developed in the derivation cohort through iterative multivariable logistic regression analyses that maximized the area under the receiver-operating curve (AUC). External validity was assessed using the validation cohort.

RESULTS

A total of 897 SOT recipients with an EB BSI were included, of which 539 were assigned to the derivation cohort (135, 25% ESBL-EB) and 358 to the validation cohort (221, 62% ESBL-EB). Using multivariable analyses, the most parsimonious model that was predictive of ESBL-EB BSI consisted of 10 variables, which fell into four clinical categories: prior colonization or infection with EB organisms, recent antimicrobial exposures, severity of preceding illness, and immunosuppressive regimen. This model achieved an AUC of 0.81 in the derivation cohort and 0.68 in the validation cohort.

CONCLUSIONS

Though further refinements are needed in additional populations, this tool shows promise for guiding empiric therapy for SOT recipients with EB BSI.

Recent chemical syntheses of bacteria related oligosaccharides using modern expeditious approaches

Apart from some essential and crucial roles in life processes carbohydrates also are involved in a few detrimental courses of action related to human health, like infections by pathogenic microbes, cancer metastasis, transplanted tissue rejection, etc. Regarding management of pathogenesis by microbes, keeping in mind of multi drug-resistant bacteria and epidemic or endemic incidents, preventive measure by vaccination is the best pathway as also recommended by the WHO; by vaccination, eradication of bacterial diseases is also possible. Although some valid vaccines based on attenuated bacterial cells or isolated pure polysaccharide-antigens or the corresponding conjugates thereof are available in the market for prevention of several bacterial diseases, but these are not devoid of some disadvantages also. In order to develop improved conjugate T-cell dependent vaccines oligosaccharides related to bacterial antigens are synthesized and converted to the corresponding carrier protein conjugates. Marketed Cuban Quimi-Hib is such a vaccine being used since 2004 to resist Haemophilus influenza b infections. During nearly the past two decades research is going on worldwide for improved synthesis of bacteria related oligosaccharides or polysaccharides towards development of such semisynthetic or synthetic glycoconjugate vaccines. The present dissertation is an endeavour to encompass the recent syntheses of several pathogenic bacterial oligosaccharides or polysaccharides, made during the past ten-eleven years with special reference to modern expeditious syntheses.

Changes in Antibiotic Resistance in Recurrent Pseudomonas Aeruginosa Infections of Chronic Suppurative Otitis Media

This study investigated the changes in antibiotic resistance in recurrent Pseudomonas aeruginosa infections in chronic suppurative otitis media (CSOM). Its aim was to provide a treatment strategy for P aeruginosa infections in CSOM for the prevention of multidrug resistance. A case-control study was conducted in tertiary teaching hospitals in Korea. The experimental group included patients with recurrent P aeruginosa infection who had relapsed within 2 months after the successful control of a previous P aeruginosa infection. The control group consisted of patients with a P aeruginosa infection who had no history of such an infection. An antibiotic sensitivity test was performed for each culture. The proportion of recurrent P aeruginosa infection was 22.69% (98 of 432 cases). Drug resistance to amikacin, tobramycin, netilmicin, ciprofloxacin, and levofloxacin was significantly changed after recurrent infection. The fluoroquinolone strains seen in recurrent P aeruginosa showed high cross-resistance to other drugs. Antibiotic resistance of P aeruginosa in CSOM changed with recurrent infection.

Effect of the lantibiotic nisin on inhibitory and bactericidal activities of antibiotics used against vancomycin-resistant enterococci

OBJECTIVES

Antibiotic resistance is a serious issue facing clinicians all over the world. Vancomycin-resistant enterococci (VRE) are amongst the most common resistant pathogens that are isolated from patients suffering from infections in our locality. New antimicrobial agents such as the lantibiotic nisin have been previously examined against resistant bacteria as it has strong antibacterial action with no chance of resistance development. This study aimed to explore the effect of nisin in combination with the conventional antibiotics against VRE, with a view to using it as an auxiliary therapy with such antibiotics for combating resistant isolates.

METHODS

Twenty-three VRE had been examined for the combined effect of nisin with the routine sets of antibiotics using the microplate dilution technique for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) testing. Checkerboard microbroth assay was conducted for inspection of synergism between nisin and either ampicillin or chloramphenicol.

RESULTS

An obvious improvement of inhibitory and bactericidal activities of the tested antibiotics after addition of lantibiotic nisin was observed, with a remarkable reduction in the MIC values of vancomycin against all of the isolates. Nisin recorded a synergistic outcome when combined with either ampicillin or chloramphenicol using the checkerboard assay.

CONCLUSION

Nisin could be effectively considered as a supplementary agent to traditional antibiotics in the management of VRE-associated infections, as it had a synergistic outcome with commonly prescribed antibiotics such as ampicillin and chloramphenicol.

Bringing Community Ecology to Bear on the Issue of Antimicrobial Resistance

Antimicrobial resistance (AMR) is a global concern, pertaining not only to human health but also to the health of industry and the environment. AMR research has traditionally focused on genetic exchange mechanisms and abiotic environmental constraints, leaving important aspects of microbial ecology unresolved. The genetic and ecological aspects of AMR, however, not only contribute separately to the problem but also are interrelated. For example, mutualistic associations among microbes such as biofilms can both serve as a barrier to antibiotic penetration and a breeding ground for horizontal exchange of antimicrobial resistance genes (ARGs). In this review, we elucidate how species interactions promote and impede the establishment, maintenance, and spread of ARGs and indicate how management initiatives might benefit from leveraging the principles and tools of community ecology to better understand and manipulate the processes underlying AMR.

Characterization of genetic changes associated with daptomycin nonsusceptibility in Staphylococcus aureus

The extensive use of daptomycin (DAP) for treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections in the last decade has led to the emergence of DAP non-susceptible (DNS) Staphylococcus aureus strains. A better understanding of the molecular changes underlying DAP-non-susceptibility is required for early diagnosis and intervention with alternate combination therapies. The phenotypic changes associated with DNS strains have been well established. However, the genotypic changes—especially the kinetics of expression of the genes responsible for DAP-non-susceptibility are not well understood. In this study, we used three clinically derived isogenic pairs of DAP-susceptible (DAP-S) and DNS S. aureus strains to study gene expression profiles with the objective of identifying the potential genotypic changes associated with DAP-nonsusceptibility. We determined the expression profiles of genes involved in cell membrane (CM) charge, autolysis, cell wall (CW) synthesis, and penicillin binding proteins in DAP-S and DNS isogenic pairs. Our results demonstrate characteristic expression profiles for mprF, dltABCD, vraS, femB, and pbp2a genes, which are common to all the DNS S. aureus strains tested. Whole genome sequencing of DAP-S and DNS clinical isolates of S. aureus showed non-synonymous mutations in all DNS strains in genes involved in CM charge, CM composition, CW thickness and CW composition. To conclude, this study unravels some of the complex molecular changes involved in the development of DAP-nonsusceptibility by demonstrating distinct differences in gene expression profiles and mutations in the DNS S. aureus strains. This knowledge will aid in rapid identification of DNS S. aureus in clinical settings.

Treating resistant Pseudomonas aeruginosa lung disease in young children with cystic fibrosis

Pseudomonas aeruginosa is a common bacterial pathogen in the evolution of bronchiectasis in cystic fibrosis. The appearance of resistant strains of pseudomonas is increasing with the earlier and more liberal use of a range of anti-pseudomonal antibiotics for the treatment of bacterial chest infections. The rationale for treatment and potential benefits of aggressive treatment of resistant strains of Pseudomonas aeruginosa from early in life are discussed.

Prevalence and risk factors of Gram-negative bacilli causing blood stream infection in patients with malignancy

Objectives:

To evaluate the epidemiology, risk factors, and antibiotic resistance of Gram negative bacteria (GNB) in patients with hematologic or solid organ malignancies.

Methods:

This is a retrospective study of 61 episodes of GNB bacteremia occurring in 56 patients with malignancy admitted to the Oncology Units in King Khalid University Hospital, Riyadh. Kingdom of Saudi Arabia during the period from January 2013 to October 2015. Data were retrieved from the computerized database of the microbiology laboratory and the patient’s medical records.

Results:

Hematological malignancies accounted for 30 (54%) and solid tumors accounted for 26 (46%). The most common hematological malignancies were leukemia 23 (77%), followed by lymphoma 6 (20%). Among solid tumors, colorectal cancer 9 (34.6) and breast cancer 6 (23%) were the most common. The most predominant pathogen was Escherichia coli (E. coli) (29.5%) followed by Acinetobacter baumannii (A. baumannii) (18%). The extended-spectrum beta-lactamases producers rate of E. coli and Klebsiella pneumonia was (34.6%). Imipenem resistance among Pseudomonas aeruginosa/A. baumannii was high (52.4%). The multi-resistant organisms rate was (43.5%). Risk factors associated with the bacteremia were ICU admission (32.1%), post-surgery (23.2%), and placement of central line (21.4%). The overall 30-day mortality rate of the studied population was high (32.1%).

Conclusion:

In light of the high resistant rate among the GNB isolated from malignancy patients from our institution, careful selection of antimicrobial treatment based on antimicrobial susceptibility testing is recommended.

Can a collaborative subspecialty antimicrobial stewardship intervention have lasting effects?

OBJECTIVE

We previously demonstrated the benefit of direct, daily collaboration between infectious disease (ID) and critical care practitioners (CCP) on guideline adherence and antibiotic use in the medical intensive care unit (MICU). In this post-intervention review, we sought to establish whether the effect on antibiotic use and guideline adherence was sustainable.

DESIGN

A retrospective review of 87 patients, admitted to the 24-bed MICU, was done 3 (n = 45) and 6 months (n = 42) after the intervention.

MEASUREMENTS

Data included demographics, severity indicators, admitting pathology, infectious diagnosis, clinical outcomes [mechanical ventilation days (MVD) and MICU length of stay (LOS), antibiotic days of therapy (DOT), in-hospital mortality], and antibiotic appropriateness based on current guidelines.

RESULTS

In the 3-month (3-PI) and 6-month post-intervention (6-PI), there were no significant differences in the APACHE II score, MVD, LOS, DOT, or total antibiotic use at 3 (p = 0.59) and 6-PI (p = 0.87). There was no change in the mean use of extended-spectrum penicillins, cephalosporin, and carbapenems. While there were significant differences in vancomycin usage at 3-PI [3.1 DOT vs. 4.3 DOT (p = 0.007)], this finding was not seen after 6 months [3.1 DOT vs. 3.4 DOT (p = 0.08)]. When compared to the intervention period, the inappropriateness of antibiotic use at 3 (p = 1.00) and 6-PI (p = 0.30) did not change significantly.

CONCLUSIONS

There were no significant differences in either total antibiotic use or inappropriate antibiotic use at the 6-PI time period. Continuous, daily, direct collaboration between ID and CCP, once implemented, can have lasting effects even at 6 months after the interaction has been discontinued.

The effect of a continuous educational program on handwashing compliance among healthcare workers in an intensive care unit

Handwashing is simple, cost-effective and the single most important measure in the prevention of transmission of multiple antibiotic-resistant bacteria, which can spread via the contaminated hands of healthcare workers (HCWs) in intensive care units (ICUs). Despite this simplicity and efficacy, compliance with handwashing protocols is unsatisfactory among HCWs in ICUs. No single interventional measure is successful in improving handwashing compliance.

A continuous educational program was started in February 1998 by the department of infection control, emphasising the importance of handwashing in the prevention of nosocomial infections in the ICU. It took the form of posters, lectures and regular discussions. The posters were pasted in all the strategic areas of the ICU, displaying the indications and precise technique of handwashing. HCWs were directly observed for handwashing compliance, while working in the ICU. Each indication of handwashing was counted as an opportunity of handwashing.

Assessment of handwashing compliance was made once a year during the educational programme. In the final annual assessment in February 2002, out of 1,175 opportunities of handwashing, compliance was observed in 856 (72.8%) among all categories of staff. Highest compliance of 97.5% was recorded among nurses. The compliance among technicians was 47.7%, while the lowest compliance of 37.6% was observed among doctors (RR 2.591, p<0.0001). Opportunities of handwashing utilised with good technique were observed among 98.2% nurses. Handwashing compliance among females was significantly higher (76.2% versus 23.8%) than the male HCWs (RR 3.196, p<0.0001).

A comparative study of the yearly assessments made since the start of the educational program also revealed significant increases in handwashing compliance among nurses (p<0.0001) and technicians (p<0.001), while no statistically significant changes in the handwashing behaviour among doctors was observed during the study period (February 1998 to February 2002).

Disappointing handwashing compliance among doctors visiting and working in the ICU, despite their better understanding of hospital-acquired infections (HAI) and continuous educational programme remains a cause for concern. Additional efforts are required to discover more effective interventional measures to improve handwashing compliance among doctors.

Why Is It That Internists Do Not Follow Guidelines for Preventing Intravascular Catheter Infections?

Background and Objective:

High morbidity of CVC-related infections has led to national guidelines for their prevention. Despite recommendations for the use of maximal barrier precautions (mask, sterile gloves, gown, and large drape) and skin antisepsis with 2% Chlorhexidine gluconate during CVC insertion, internists in the United States are not implementing these practices frequently. This study sought to identify and characterize the obstacles to and potential opportunities for improving adherence.

Design:

Cross-sectional survey.

Participants:

One thousand randomly selected physician-members of the American College of Physicians-American Society of Internal Medicine.

Methods:

Several potential determinants of adherence to maximal barrier precautions were assessed, including awareness of, agreement with, and ability to implement the recommendation, as well as the practice and training characteristics of the respondents. Factors influencing antiseptic selection were also recorded.

Results:

Of 526 respondents, 178 (34%) had recently inserted CVCs. Clinician experience and subspecialty, awareness of CDC guidelines, and external influences (eg, time to collect equipment) did not affect maximal barrier precautions adherence. The only independent predictor of adherence was high outcome expectancy for the use of large sterile drapes (OR, 5.3; CI95, 2.2-12.6). Availability had the greatest influence on internists' selection of specific antiseptic agents, whereas cost was the least important determinant.

Conclusions:

Despite established efficacy, use of maximal barrier precautions and Chlorhexidine gluconate is low among internists. Because improved adherence to these practices will require increased outcome expectancy for maximal barrier precautions and availability of Chlorhexidine gluconate, targeting these areas through focused education and systems modifications is essential (Infect Control Hosp Epidemiol2005;26:525-533).

Catheter-Related Vancomycin-ResistantEnterococcus FaeciumBacteremia: Clinical and Molecular Epidemiology

Objective:

To study the clinical and molecular epidemiology of vancomycin-resistantEnterococcus faeciumorganisms causing catheter-related bacteremia in patients with cancer.

Design:

Retrospective case-control study.

Setting:

University of Texas M. D. Anderson Cancer Center, a tertiary-care hospital in Houston, Texas.

Patients:

Case-patients were patients with cancer who had catheter-related vancomycin-resistantE. faeciumbacteremia and control-patients were patients with cancer and vancomycin-resistantE. faeciumgastrointestinal colonization without infection.

Results:

Ten case-patients with catheter-related vancomycin-resistantE. faeciumbacteremia were compared with 30 control-patients with gastrointestinal colonization by vancomycin-resistantE. faecium. Patients with catheter-related vancomycin-resistantE. faeciumbacteremia were more likely to have required mechanical ventilation (P< .01), received total parenteral nutrition (P< .01), and had polyurethane catheters (P< .01) inserted in the femoral vein (P= .01). With the use of pulsed-fleld gel electrophoresis, 4 of the 10 catheter-related vancomycin-resistantE. faeciumbacteremia isolates were genetically indistinguishable, whereas only 2 of the 30 control vancomycin-resistantE. faeciumisolates displayed this same DNA pattern (P= .03).

Conclusion:

This study suggests that catheter-related vancomycin-resistantE. faeciumbacteremia occurs more frequently in patients who receive total parenteral nutrition, mechanical ventilation, and femoral catheters. (Infect Control Hosp Epidemiol 2005;26:658-661)

Bioprosthetic Aortic Valve Endocarditis in Association with Enterococcus durans

Enterococci are common organisms associated with endocarditis, but infection by Enterococcus durans is very rare. To our knowledge, only 3 cases have been reported in the medical literature, and all 3 have involved native valves. Here we publish the first reported case (to our knowledge) of E. durans endocarditis in association with a bioprosthetic aortic valve. After the organism and its antibiotic susceptibility were identified, the 74-year-old male patient was treated successfully with teicoplanin and gentamicin, over a course of 6 weeks.

A new approach to Vancomycin utilization evaluation: A cross-sectional study in intensive care unit

Objective:

The risk of methicillin-resistant Staphylococcus aureus infections in Intensive Care Unit (ICU) is increasing in recent years with high rate of morbidity and mortality. Therefore, in this study, we aimed to evaluate the rationale use of vancomycin in ICU patients.

Methods:

A total of 200 patients who received at least 48 h intravenous vancomycin were randomly selected from ICU wards, during 9 months. Vancomycin administration and related clinical and laboratory data were gathered from patients' charts and health information system to evaluate the appropriateness of different aspects of vancomycin use during all days which vancomycin were ordered.

Findings:

During the study, 15,230 ± 1216 mg (mean ± standard error of the mean [SEM]) vancomycin was administered for 200 patients in the mean period of 9.79 ± 0.64 (SEM) days of ICU stay, for prophylaxis and empiric therapy. Results showed the appropriateness of vancomycin uses were 30.5%, 9%, and 5.5% in the first 24 h, after 72 h and during the whole time of treatment, respectively. In addition, infectious consultation was the only significantly different parameter between appropriate and inappropriate vancomycin administration groups (P < 0.001).

Conclusion:

Although vancomycin utilization evaluation were mentioned in previous studies, but data related to ICU patients and during all days of vancomycin therapy are limited. High prevalence of inappropriate use of vancomycin in ICU is alarming for health systems and necessitates implementation of antibiotic policies.

[Nosocomial pneumonia in ICU CHU Hassan II of Fez]

L'objectif principal de notre étude était d'identifier les bactéries incriminées dans la pneumopathie nosocomiale (PN) au service de réanimation A1 du CHU Hassan II de Fès, en vue d'en améliorer la prise en charge et de diminuer la morbi-mortalité associée. Il s'agit d'une étude rétrospective et descriptive, menée du 1er janvier 2012 au 31 décembre 2013. Seules les infections pulmonaires survenant au-delà de 48 heures de l'admission du patient au service de réanimation ont été incluses. L'incidence de la PN était de 11,2%. Les Bacilles à Gram négatif (BGN) étaient retrouvés dans 48,5% des cas, le Staphylocoque Aureus dans 21,21% des cas et le Klebsiella Pneumoniae était dans 10,7% des cas. Le taux de mortalité était de 48,33%. L’âge, la gravité de la pathologie sous jacente et le retard de l'instauration d'une antibiothérapie adaptée étaient considérées comme facteurs de mauvais pronostic. L’étude de la résistance aux antibiotiques, montre une multirésistance surtout pour les BGN, dont il faut tenir compte en mettant en place une stratégie de prévention active.

Clinico-microbiological study of Pseudomonas aeruginosa in wound infections and the detection of metallo-β-lactamase production

Pseudomonas aeruginosa is a common opportunistic pathogen of humans among the Gram-negative bacilli. Clinically, it is associated with nosocomial infections like burns and surgical-site wound infections and remains a major health concern, especially among critically ill and immunocompromised patients. This is a prospective laboratory-based 2 year study conducted to isolate P. aeruginosa from wound specimens and the antimicrobial susceptibility pattern with reference to metallo-β-lactamase (MBL) production. Two hundred and twenty-four samples of P. aeruginosa isolated from wound specimens were included in the study. Antimicrobial susceptibility was done as per Clinical Laboratory Standard Institute (CLSI) guidelines. MBL-producing P. aeruginosa was detected using the EDTA disk diffusion synergy test. Statistical analysis was done using the SPSS 11 package (SPSS Inc., Chicago, IL). Out of the 224 P. aeruginosa isolates, 100% were susceptible to polymyxin B and colistin, 92·8% were sensitive to imipenem, 38% showed resistance to gentamicin followed by ceftazidime (31·69%) and meropenem (33·03). Sixteen (7·14%) isolates showed MBL production. Infection caused by drug-resistant P. aeruginosa is important to identify as it poses a therapeutic problem and is also a serious concern for infection control management. The acquired resistance genes can be horizontally transferred to other pathogens or commensals if aseptic procedures are not followed.

Hydrogel Antimicrobial Capture Coatings for Endotracheal Tubes: A Pharmaceutical Strategy Designed to Prevent Ventilator-Associated Pneumonia

This paper presents a novel strategy for the prevention of ventilator-associated pneumonia that involves coating poly(vinyl chloride, PVC) endotracheal tubes (ET) with hydrogels that may be subsequently used to entrap nebulized antimicrobial solutions. Candidate hydrogels were prepared containing a range of ratios of hydroxyethyl methacrylate (HEMA) and methacrylic acid (MAA) from 100:0 to 70:30 using free radical polymerization and, when required, simultaneous attachment to PVC was performed. The mechanical properties, glass transition temperatures, swelling kinetics, uptake of gentamicin from an aqueous medium, and gentamicin release were characterized. Increasing the MAA content of the hydrogels significantly decreased the ultimate tensile strength, % elongation at break, Young's modulus, and increased the glass transition temperature, the swelling ratio, and gentamicin uptake. Microbial (Staphylococcus aureus and Pseudomonas aeruginosa) adherence to control (drug-free) hydrogels was observed; however, while adherence to gentamicin-containing p(HEMA) occurred, no adherence occurred to gentamicin-containing HEMA:MAA copolymers. Antimicrobial persistence of gentamicin-containing hydrogels was examined by determining the zone of inhibition against each microorganism on successive days. Hydrogel composition affected the observed antimicrobial persistence, with the hydrogel composed of 70:30 HEMA:MAA exhibiting >20 days persistence against S. aureus and P. aeruginosa, respectively. To simulate clinical use, the hydrogels (coated onto PVC) were first exposed to a nebulized solution of gentamicin (4 mL, 80 mg for 20 min), and then to nebulized bacteria (4 mL ca. 1×10(9) colony forming units mL(-1), 30 min). Viable bacteria were not observed on the gentamicin-treated p(HEMA: MAA) copolymers, whereas growth was observed on gentamicin-treated p(HEMA). In light of the excellent antimicrobial activity and physicochemical properties, p(HEMA: MAA) copolymers composed of ratios of 80:20 or 70:30 HEMA: MAA were identified as potentially useful coatings of endotracheal tubes to be used in conjunction with the clinical nebulization of gentamicin and designed for the prevention of ventilator-associated pneumonia.

Epidemiology and Outcomes of Hospitalizations with Complicated Skin and Skin-Structure Infections: Implications of Healthcare-Associated Infection Risk Factors

Objective.

Healthcare-associated infections are likely to be caused by drug-resistant and possibly mixed organisms and to be treated with inappropriate antibiotics. Because prompt appropriate treatment is associated with better outcomes, we studied the epidemiology of healthcare-associated complicated skin and skin-structure infections (cSSSIs).

Patients.

Persons hospitalized with cSSSI and a positive culture result.

Methods.

We conducted a single-center retrospective cohort study from April 2006 through December 2007. We differentiated healthcare-associated from community-acquired cSSSIs by at least 1 of the following risk factors: (1) recent hospitalization, (2) recent antibiotics, (3) hemodialysis, and (4) transfer from a nursing home. Inappropriate treatment was defined as no antimicrobial therapy with activity against the offending pathogen(s) within 24 hours after collection of a culture specimen. Mixed infections were those caused by both a gram-positive and a gram-negative organism.

Results.

Among 717 hospitalized patients with cSSSI, 527 (73.5%) had healthcare-associated cSSSI. Gram-negative organisms were more common (relative risk, 1.24 [95% confidence interval, 1.14–1.35) and inappropriate treatment trended toward being more common (odds ratio, 1.29 [95% confidence interval, 0.85–1.95]) in healthcare-associated cSSSI than in community-acquired cSSSI. Mixed cSSSIs occurred in 10.6% of patients with healthcare-associated cSSSI and 6.3% of those with community-acquired cSSSI (P = .082) and were more likely to be treated inappropriately than to be nonmixed infections (odds ratio, 2.42 [95% confidence interval, 1.43–4.10]). Both median length of hospital stay (6.2 vs 2.9 days; P < .001) and mortality rate (6.6% vs 1.1%; P = .003) were significantly higher for healthcare-associated cSSSI than community-acquired cSSSI.

Conclusions.

Healthcare-associated cSSSIs are common and are likely to be caused by gram-negative organisms. Mixed infections carry a <2-fold greater risk of inappropriate treatment. Healthcare-associated cSSSIs are associated with increased mortality and prolonged length of hospital stay, compared with community-acquired cSSSIs.

Ventilator-Associated Pneumonia at a Tertiary-Care Center in a Developing Country: Incidence, Microbiology, and Susceptibility Patterns of Isolated Microorganisms

Objective:

Ventilator-associated pneumonia (VAP) complicates the course of up to 24% of intubated patients. Data from the Middle East are scarce. The objective of this study was to evaluate the incidence, microbiology, and antimicrobial susceptibility patterns of isolated microorganisms in VAP in a developing country.

Design:

Prospective observational cohort study.

Setting:

The American University of Beirut Medical Center, a tertiary-care center that serves as a major referral center for Lebanon and neighboring countries.

Patients:

All patients admitted to the intensive care and respiratory care units from March to September 2001, and who had been receiving mechanical ventilation for at least 48 hours, were included in the study. Results of samples submitted for culture were recorded and antimicrobial susceptibility testing of isolated pathogens was performed.

Results:

Seventy patients were entered into the study. The incidence of VAP was 47%. Gram-negative bacilli accounted for 83% of all isolates. The most commonly identified organism was Acinetobacter anitratus, followed by Pseudomonas aeruginosa. Fifty percent of all gram-negative bacterial isolates were classified as antibiotic resistant. Compared with patients without VAP, patients with VAP remained intubated for a longer period and stayed in the intensive care unit longer. VAP was not associated with an increased mortality rate.

Conclusion:

Compared with other studies, the results from this referral center in Lebanon indicate a higher incidence of VAP and a high prevalence of resistant organisms. These data are relevant because they direct the choice of empiric antibiotic therapy for VAP.

Do Infection Control Measures Work for Methicillin-ResistantStaphylococcus aureus?

Objective:

To review evidence regarding the effectiveness of control measures in reducing transmission of methicillin-resistantStaphylococcus aureus(MRSA) in hospitals.

Design:

Literature review and surveillance cultures of hospitalized patients at high risk for MRSA colonization or infection.

Setting:

A 500-bed, university-affiliated, community teaching hospital.

Results:

The percentage of nosocomialS. aureusinfections caused by MRSA increased significantly between 1982 and 2002, despite the use of various isolation and barrier precaution policies. The apparent ineffectiveness of control measures may be due to several factors including the failure to identify patients colonized with MRSA For example, cultures of stool specimens submitted forClostridium difficiletoxin assays at one hospital found that 12% of patients had MRSA in their stool, and 41% of patients with unrecognized colonization were cared for without using barrier precautions. Other factors include the use of barrier precaution strategies that do not account for multiple reservoirs of MRSA, poor adherence of healthcare workers (HCWs) to recommended barrier precautions and handwashing, failure to identify and treat HCWs responsible for transmitting MRSA, and importation of MRSA by patients admitted from other facilities. Control programs that include active surveillance cultures (ASCs) of high-risk patients and use of barrier precautions have reduced MRSA prevalence rates and have been cost-effective. Using a staged approach to implementing ASCs can minimize logistic problems.

Conclusion:

MRSA control programs are effective if they include ASCs of high-risk patients, use of barrier precautions when caring for colonized or infected patients, hand hygiene, and treating HCWs implicated in MRSA transmission.

Micro-Raman, mid-IR, far-IR and DFT studies on 2-[4-(4-fluorobenzamido)phenyl]benzothiazole

Molecular structure of 2-[4-(4-Fluorobenzamido)phenyl]benzothiazole was determined by quantum chemical calculations. MidIR and FarIR spectra were recorded at room temperature, with 4 cm(-1) resolution in the 4000-400 cm(-1) and 700-30 cm(-1) regions, respectively for the first time. Raman spectrum was recorded in the 4000-100 cm(-1) range. Optimized molecular structure and vibrational wavenumbers of the compound in its ground state have been calculated by using Density Functional Theory using B3LYP functional with 6-311++G(d,p) basis set. Vibrational wavenumbers were seen to be in good agreement with the experimental IR data. Furthermore, assignments of each vibrational mode were interpreted in terms of potential energy distributions in detail.

Recommendations for the empirical treatment of complicated urinary tract infections using surveillance data on antimicrobial resistance in the Netherlands

BACKGROUND

Complicated urinary tract infections (c-UTIs) are among the most common nosocomial infections and a substantial part of the antimicrobial agents used in hospitals is for the treatment of c-UTIs. Data from surveillance can be used to guide the empirical treatment choices of clinicians when treating c-UTIs. We therefore used nation-wide surveillance data to evaluate antimicrobial coverage of agents for the treatment of c-UTI in the Netherlands.

METHODS

We included the first isolate per patient of urine samples of hospitalised patients collected by the Infectious Disease Surveillance Information System for Antibiotic Resistance (ISIS-AR) in 2012, and determined the probability of inadequate coverage for antimicrobial agents based on species distribution and susceptibility. Analyses were repeated for various patient groups and hospital settings.

RESULTS

The most prevalent bacteria in 27,922 isolates of 23,357 patients were Escherichia coli (47%), Enterococcus spp. (14%), Proteus mirabilis (8%), and Klebsiella pneumoniae (7%). For all species combined, the probability of inadequate coverage was <5% for amoxicillin or amoxicillin-clavulanic acid combined with gentamicin and the carbapenems. When including gram-negative bacteria only, the probability of inadequate coverage was 4.0%, 2.7%, 2.3% and 1.7%, respectively, for amoxicillin, amoxicillin-clavulanic acid, a second or a third generation cephalosporin in combination with gentamicin, and the carbapenems (0.4%). There were only small variations in results among different patient groups and hospital settings.

CONCLUSIONS

When excluding Enterococcus spp., considered as less virulent, and the carbapenems, considered as last-resort drugs, empirical treatment for c-UTI with the best chance of adequate coverage are one of the studied beta-lactam-gentamicin combinations. This study demonstrates the applicability of routine surveillance data for up-to-date clinical practice guidelines on empirical antimicrobial therapy, essential in patient care given the evolving bacterial susceptibility.

Catheter related blood stream infections in the paediatric intensive care unit: A descriptive study

Context:

Catheter related blood stream infections (CRBSI) contributes significantly to morbidity, mortality and costs in intensive care unit (ICU). The patient profile, infrastructure and resources in ICU are different in the developing world as compared to western countries. Studies regarding CRBSI from pediatric intensive care unit (PICU) are scanty in the Indian literature.

Aims:

To determine the frequency and risk factors of CRBSI in children admitted to PICU.

Settings and Design:

Descriptive study done in the PICU of a tertiary care teaching hospital over a period of four months.

Materials and Methods:

Study children were followed up from the time of catheterization till discharge. Their clinical and treatment details were recorded and blood culture was done every 72 h, starting at 48 h after catheterization. The adherence of doctors to Centre for Disease Control (CDC) guidelines for catheter insertion was assessed using a checklist.

Statistical Analysis:

Clinical parameters were compared between colonized and non-colonized subjects and between patients with and without CRBSI. Unpaired t-test and Chi-square test were used to test the significance of observed differences.

Results:

Out of the 41 children, 21 developed colonization of their central venous catheter (66.24/1000 catheter days), and two developed CRBSI (6.3/1000 catheter days). Infants had a higher risk for developing colonization (P = 0.01). There was 85% adherence to CDC guidelines for catheter insertion.

Conclusions:

The incidence of CRBSI and catheter colonization is high in our in spite of good catheter insertion practices. Hence further studies to establish the role of adherence to catheter maintenance practices in reducing risk of CRBSI is required. The role of a composite package of interventions including insertion and maintenance bundles specifically targeting infants needs to be studied to bring down the catheter colonization as well as CRBSI rates.

The anti-Pseudomonas aeruginosa antibody Panobacumab is efficacious on acute pneumonia in neutropenic mice and has additive effects with meropenem

Pseudomonas aeruginosa (P. aeruginosa) infections are associated with considerable morbidity and mortality in immunocompromised patients due to antibiotic resistance. Therefore, we investigated the efficacy of the anti-P. aeruginosa serotype O11 lipopolysaccharide monoclonal antibody Panobacumab in a clinically relevant murine model of neutropenia induced by cyclophosphamide and in combination with meropenem in susceptible and meropenem resistant P. aeruginosa induced pneumonia. We observed that P. aeruginosa induced pneumonia was dramatically increased in neutropenic mice compared to immunocompetent mice. First, Panobacumab significantly reduced lung inflammation and enhanced bacterial clearance from the lung of neutropenic host. Secondly, combination of Panobacumab and meropenem had an additive effect. Third, Panobacumab retained activity on a meropenem resistant P. aeruginosa strain. In conclusion, the present data established that Panobacumab contributes to the clearance of P. aeruginosa in neutropenic hosts as well as in combination with antibiotics in immunocompetent hosts. This suggests beneficial effects of co-treatment even in immunocompromised individuals, suffering most of the morbidity and mortality of P. aeruginosa infections.

Frequency of the off-label use of antibiotics in clinical practice: a systematic review

Antibiotics constitute a major class among drugs commonly prescribed either empirically or for microbiologically documented infections in clinical practice. In addition, due to medical necessity physicians are forced, at times, to prescribe medications for off-label indications. The authors sought to record the frequency of the off-label use of antibiotics among both adult and pediatric patients. PubMed and Scopus databases were searched to identify relevant studies. A total of 25 studies met the inclusion criteria (725,124,505 prescriptions); 16 were prospective and nine retrospective. Fifteen studies reported on the pediatric population, seven on adults who had received a specific antibiotic, two on adult critical-care patients, and one on the general outpatient population. In the pediatric population, the percentage of off-label prescriptions varied from 1 to 94%. Off-label prescriptions varied from 19 to 43% in adult critical-care patients. Last, one study reporting on general outpatient care showed that 23% of prescriptions were off-label. Antibiotics are frequently prescribed as off-label among patient populations. The wide variation observed in the off-label use of antibiotics among pediatric patients might be attributed to the heterogeneity among the study populations regarding the age of children. Although this unapproved manner of prescribing cannot always be avoided, clinicians should only use unapproved drugs in cases when there are no effective alternatives are available and based on scientific evidence regarding safety and effectiveness.

Characterisation of aerobic bacteria isolated from endotracheal aspirate in adult patients suspected ventilator associated pneumonia in a tertiary care center in Mangalore

BACKGROUND AND OBJECTIVES

Despite advances in antimicrobial therapy, better supportive care modalities and use of a wide range of preventive measures, ventilator-associated pneumonia (VAP) continues to be an important cause of morbidity and mortality in intensive care unit (ICU). VAP requires a rapid diagnosis and initiation of appropriate antibiotic treatment, to prevent mortality and morbidity. Inappropriate and inadequate antibiotic treatment causes emergence of drug resistance in pathogens and poor prognosis in patients. Early detection of pathogens causing VAP helps to control their spread by administration of suitable antibiotics and proper infection control measures. The study was conducted to know the pathogens causing VAP in Fr. Muller Medical College Hospital, Mangalore, and their susceptibility pattern.

METHODS

A total of 100 patients, on mechanical ventilation for more than 48 h, who were suspected to have VAP were included in the study between December 2008 and November 2009. Their endotracheal aspirates (ETAs) were collected and processed. From 100 ETA, 138 isolates of count > 10(5) CFU/ mL were characterized and antibiogram was determined using standard antibiotics regime.

RESULTS

Incidence of VAP was found to be 44.2% among the mechanically ventilated patients. Klebsiella pneumoniae (34%) was the most common pathogen isolated, followed by Pseudomonas aeruginosa (20%). Among them, most of the K. pneumoniae and P. aeruginosa isolates were resistant to penicillins, cephalosporins, fluoroquinolones was observed but were sensitive to piperacillin/tazobactum, cefaperazone/sulbactum, and carbapenems. All isolates were sensitive to amikacin.

INTERPRETATION AND CONCLUSION

The present study shows prevalence of multidrug-resistant organisms in the study region. Klebsiella species was the most common pathogen isolated in ETA. Acinetobacter species were the most resistant pathogens prevailing in our ICU setup, leading to the increased mortality in the ventilated patients. Patients with chronic obstructive pulmonary disease is the most common predisposing factor for VAP in the study group.

Relationship between chlorhexidine gluconate skin concentration and microbial density on the skin of critically ill patients bathed daily with chlorhexidine gluconate

OBJECTIVE AND DESIGN

Previous work has shown that daily skin cleansing with chlorhexidine gluconate (CHG) is effective in preventing infection in the medical intensive care unit (MICU). A colorimetric, semiquantitative indicator was used to measure CHG concentration on skin (neck, antecubital fossae, and inguinal areas) of patients bathed daily with CHG during their MICU stay and after discharge from the MICU, when CHG bathing stopped.

PATIENTS AND SETTING

MICU patients at Rush University Medical Center.

METHODS

CHG concentration on skin was measured and skin sites were cultured quantitatively. The relationship between CHG concentration and microbial density on skin was explored in a mixed-effects model using gram-positive colony-forming unit (CFU) counts.

RESULTS

For 20 MICU patients studied (240 measurements), the lowest CHG concentrations (0-18.75 μg/mL) and the highest gram-positive CFU counts were on the neck (median, 1.07 log(10) CFUs; [Formula: see text]). CHG concentration increased postbath and decreased over 24 hours ([Formula: see text]). In parallel, median log(10) CFUs decreased pre- to postbath (0.78 to 0) and then increased over 24 hours to the baseline of 0.78 ([Formula: see text]). A CHG concentration above 18.75 μg/mL was associated with decreased gram-positive CFUs ([Formula: see text]). In all but 2 instances, CHG was detected on patient skin during the entire interbath (approximately 24-hour) period (18 [90%] of 20 patients). In 11 patients studied after MICU discharge (80 measurements), CHG skin concentrations fell below effective levels after 1-3 days.

CONCLUSION

In MICU patients bathed daily with CHG, CHG concentration was inversely associated with microbial density on skin; residual antimicrobial activity on skin persisted up to 24 hours. Determination of CHG concentration on the skin of patients may be useful in monitoring the adequacy of skin cleansing by healthcare workers.

Infections caused by multidrug resistant organisms are not associated with overall, all-cause mortality in the surgical intensive care unit: the 20,000 foot view

BACKGROUND

Resistant pathogens are increasingly common in the ICU, with controversy regarding their relationship to outcomes. We hypothesized that an increasing number of infections with resistant pathogens in our surgical ICU would not be associated with increased overall mortality.

STUDY DESIGN

All ICU-acquired infections were prospectively identified between January 1, 2000 and December 31, 2009 in a single surgical ICU. Crude in-hospital, all-cause mortality data were obtained using a prospectively collected ICU database. Trends in rates were compared using linear regression.

RESULTS

A total of 799 resistant pathogens were identified (257 gram-positive, 542 gram-negative) from a total of 3,024 isolated pathogens associated with 2,439 ICU-acquired infections. The most frequently identified resistant gram-positive and -negative pathogens (defined as resistant to at least 1 major class of antimicrobials) were methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa, respectively. Pathogens were most commonly isolated from the lung, blood, and urine. The crude mortality rate declined steadily from 2000 to 2009 (9.4% to 5.4%; equation for trend y = -0.11x + 8.26). Linear regression analysis of quarterly rates revealed a significant divergence in trends between increasing total resistant infections (equation for trend y = 0.34x + 13.02) and percentage resistant infections (equation for trend y = 0.36x + 18.66) when compared with a decreasing mortality (p = 0.0003, p < 0.0001, respectively).

CONCLUSIONS

Despite a steady rise in the proportion of resistant bacterial infections in the ICU, crude mortality rates have decreased over time. The rates of resistant infections do not appear to be a significant factor in overall mortality in our surgical ICU patients.

The deceased organ donor with an "open abdomen": proceed with caution

In solid organ transplantation, the disparity between donor supply and patients awaiting transplant continues to increase. The organ shortage has led to relaxation of historic contraindications to organ donation. A large percentage of deceased organ donors have been subjected to traumatic injuries, which can often result in intervention that leads to abdominal packing and intensive care unit resuscitation. The donor with this "open abdomen" (OA) presents a situation in which the risk of organ utilization is difficult to quantify. There exists a concern for the potential of a higher risk for both bacterial and fungal infections, including multidrug-resistant (MDR) pathogens because of the prevalence of antibiotic use and critical illness in this population. No recommendations have been established for utilization of organs from these OA donors, because data are limited. Herein, we report a case of a 21-year-old donor who had sustained a gunshot wound to his abdomen, resulting in a damage-control laparotomy and abdominal packing. The donor subsequently suffered brain death, and the family consented to organ donation. A multiorgan procurement was performed with respective transplantation of the procured organs (heart, liver, and both kidneys) into 4 separate recipients. Peritoneal swab cultures performed at the time of organ recovery grew out MDR Pseudomonas aeruginosa on the day after procurement, subsequently followed by positive blood and sputum cultures as well. All 4 transplant recipients subsequently developed infections with MDR P. aeruginosa, which appeared to be donor-derived with similar resistance patterns. Appropriate antibiotic coverage was initiated in all of the patients. Although 2 of the recipients died, mortality did not appear to be clearly associated with the donor-derived infections. This case illustrates the potential infectious risk associated with organs from donors with an OA, and suggests that aggressive surveillance for occult infections should be pursued.

Infections in vascular surgery

Infections in vascular surgery are usually of multifactorial nature resulting from a complex interplay of patient, surgical and environmental factors. Preventative measures initiated from the stage of pre-operative screening, maintenance of patient homeostasis and the use of organism-directed antibiotics can contribute to reduce infection rates. Graft preservation techniques are becoming increasingly popular as a method to treat established graft infections. In this article we report on the current trends and techniques on the management of infections in vascular surgery. Ongoing studies are required to continue to accumulate data on the effectiveness of these techniques.

Randomized comparison of 2 protocols to prevent acquisition of methicillin-resistant Staphylococcus aureus: results of a 2-center study involving 500 patients

OBJECTIVE

To compare an interventional protocol with a standard protocol for preventing the acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in the intensive care unit (ICU).

DESIGN

Prospective, randomized, controlled, parallel-group, nonblinded clinical trial.

SETTING

Medical ICUs of 2 French university hospitals.

PARTICIPANTS

Five hundred adults with an expected length of stay in the ICU greater than 48 hours.

INTERVENTIONS

For the intervention group, the protocol required repeated MRSA screening, contact and droplet isolation precautions for patients at risk for MRSA at ICU admission and for MRSA-positive patients, and decontamination with nasal mupirocin and chlorhexidine body wash for MRSA-positive patients. For the standard group, the standard precautions protocol was used, and the results of repeated MRSA screening in the standard group were not communicated to investigators.

MAIN OUTCOME MEASURE

MRSA acquisition rate in the ICU. An audit was conducted to assess compliance with hygiene and isolation precautions.

RESULTS

In the intent-to-treat analysis ([Formula: see text]), the MRSA acquisition rate in the ICU was similar in the standard (13 [5.3%] of 243) and intervention (16 [6.5%] of 245) groups ([Formula: see text]). The audit showed that the overall compliance rate was 85.5% in the standard group and 84.1% in the intervention group ([Formula: see text]), although compliance was higher when isolation precautions were absent than when they were in place (88.2% vs 79.1%; [Formula: see text]). MRSA incidence rates were higher without isolation precautions (7.57‰) than with isolation precautions (2.36‰; [Formula: see text]).

CONCLUSIONS

Individual allocation to MRSA screening, isolation precautions, and decontamination do not provide individual benefit in reducing MRSA acquisition, compared with standard precautions, although the collective risk was lower during the periods of isolation.

TRIAL REGISTRATION

Clinicaltrials.gov identifier: NCT00151606.

A clinical review of infected wound treatment with Vacuum Assisted Closure (V.A.C.) therapy: experience and case series

Over the last decade Vacuum Assisted Closure((R)) (KCI Licensing, Inc., San Antonio, TX) has been established as an effective wound care modality for managing complex acute and chronic wounds. The therapy has been widely adopted by many institutions to treat a variety of wound types. Increasingly, the therapy is being used to manage infected and critically colonized, difficult-to-treat wounds. This growing interest coupled with practitioner uncertainty in using the therapy in the presence of infection prompted the convening of an interprofessional expert advisory panel to determine appropriate use of the different modalities of negative pressure wound therapy (NPWT) as delivered by V.A.C.((R)) Therapy and V.A.C. Instill((R)) with either GranuFoam() or GranuFoam Silver() Dressings. The panel reviewed infected wound treatment methods within the context of evidence-based medicine coupled with experiential insight using V.A.C.((R)) Therapy Systems to manage a variety of infected wounds. The primary objectives of the panel were 1) to exchange state-of-practice evidence, 2) to review and evaluate the strength of existing data, and 3) to develop practice recommendations based on published evidence and clinical experience regarding use of the V.A.C.((R)) Therapy Systems in infected wounds. These recommendations are meant to identify which infected wounds will benefit from the most appropriate V.A.C.((R)) Therapy System modality and provide an infected wound treatment algorithm that may lead to a better understanding of optimal treatment strategies.

Bacterial colonization of rings and cell phones carried by health-care providers: are these mobile bacterial zoos in the hospital?

Our objective was to assess the presence of pathogenic organisms on the rings (worn on fingers) and cell phones carried by health-care workers (HCWs) and the public. Forty-two percent of mobile phones carried by HCWs and 18% carried by the general public were found to carry one or more organisms; 82% of the rings worn by HCWs and 36% of those worn by the general public were found to be positive for the presence of at least one type of microbe.

Emerging drugs for complicated skin and skin-structure infections

IMPORTANCE OF THE FILED: With the worldwide surge of MRSA, skin and skin-structure infection (SSTI) treatment has become a challenge for physicians. Cultures and antibiotic susceptibility tests for SSTIs are the rule due to the implication in morbidity and mortality rates associated with MRSA infections. The need for new antibiotics is evident and the effort to decrease antibiotic resistance is a world priority.

AREAS COVERED IN THIS REVIEW

This manuscript accesses the actual treatments and the developing of antibiotics for MRSA SSTIs.

WHAT THE READER WILL GAIN

This is a review of the data on the available and emerging treatments for MRSA SSTIs.

TAKE HOME MESSAGE

There is an unmet medical need for new antibiotics in the new millennium. As physicians, we must assure all appropriate procedures are completed in order to reduce the bacterial resistance, especially for MRSA.

Safety and efficacy of polymyxin B in multidrug resistant Gram-negative severe sepsis and septic shock

BACKGROUND AND AIMS

The emergence of multidrug resistant strains of Gram-negative bacteria, especially the lactose nonfermenters like Pseudomonas and Acinetobacter, in the intensive care units have prompted renewed worldwide interest in the polymyxins. However, perceived nephrotoxicity has been a major vexation limiting their early and regular use in severe sepsis. This study was conducted to assess the safety and efficacy of polymyxin B in patients with severe sepsis and septic shock.

MATERIALS AND METHODS

Forty-five patients with sepsis admitted in our medical-surgical intensive care units were identified from pharmacy records to have received polymyxin B. We retrospectively reviewed the clinical and microbiologic outcomes as well as occurrence of renal failure temporally related to the use of intravenous polymyxin B.

RESULTS

polymyxin B was used in severe sepsis and septic shock with the isolated organism being resistant to other available antimicrobials or clinical deterioration despite carbapenem use. Overall mortality was 52% and among patients who received at least eight days of intravenous polymyxin B, 67% patients with initial septic shock and 62% with severe sepsis survived. The target multidrug resistant organism was cleared in 88% of subjects evaluated by repeat microbiologic testing. Acute renal failure developed in only two patients (4%).

CONCLUSIONS

Polymyxin B has acceptable effectiveness against nosocomial multidrug resistant Gram-negative sepsis. The associated nephrotoxicity has been found to be significantly lower than previously reported even in patients with background renal impairment and established risk factors of renal failure.

Rotation of antimicrobial therapy in the intensive care unit: impact on incidence of ventilator-associated pneumonia caused by antibiotic-resistant Gram-negative bacteria

The development of antibiotic resistance is associated with high morbidity and mortality, particularly in the intensive care unit (ICU) setting. We evaluated the effect of an antibiotic rotation programme on the incidence of ventilator-associated pneumonia (VAP) caused by antibiotic-resistant Gram-negative bacteria. We conducted a 2-year before-and-after study at two medical-surgical ICUs at two different tertiary referral hospitals. We included all mechanically ventilated patients admitted for > or =48 h who developed VAP. From 1 January through 31 December 2007, a quarterly rotation of antibiotics (piperacillin/tazobactam, fluoroquinolones, carbapenems and cefepime/ceftazidime) for the empirical treatment of VAP was implemented. We analysed the incidence of VAP and the antibiotic resistance patterns of the responsible pathogens in 2006, before (P1) and, in 2007, after (P2) the introduction of the scheduled rotation programme. Overall, there were 79 VAP episodes in P1 and 44 in P2; the mean incidence of VAP was 20.96 cases per 1,000 days of mechanical ventilation (MV) during P1 and 14.97 in P2, with no significant difference between periods on segmented regression analysis. We observed a non-significant reduction of the number of both the poly-microbial (14 [17.7%] in P1 and 5 [10.6%] in P2 [p = 0.32]) and of the antibiotic-resistant Gram-negative bacteria-related VAP (42 [45.2%] in P1 and 16 [34%] in P2 [p = 0.21]). Conversely, the number of VAP caused by Pseudomonas aeruginosa passed from 8.35 per 1,000 days of MV in P1 to 2.33 per 1,000 days of MV in P2 (p = 0.02). No difference in ICU mortality and crude in-hospital mortality between P1 and P2 was noted. Moreover, no significant change of microbial flora isolated through clinical cultures was observed. We were able to conclude that, despite global microbial flora not being affected by such a programme, antibiotic therapy rotation may reduce the incidence of VAP caused by antibiotic-resistant Gram-negative bacteria in the ICU, such as Pseudomonas aeruginosa. The application of this programme may also improve antibiotic susceptibility. However, further studies are needed to confirm our results.

Heterogeneous Vancomycin Resistance in Staphylococcus Aureus: A Review of Epidemiology, Diagnosis, and Clinical Significance

OBJECTIVE:

To provide an overview of heterogeneously glycopeptide intermediate Staphylococcus aureus, its epidemiology, methods of diagnosis, and clinical relevance.

DATA SOURCES:

Literature was retrieved in December 2009 through Academic Search Premier, Alt-Health Watch, MEDLINE, OVID, and PubMed, using the search terms heterogeneous glycopeptide-intermediate Staphylococcus aureus, hGISA, hVISA, vancomycin-intermediate Staphylococcus aureus, GISA, and VISA (from 2003 to December 2009). Additional references were obtained through review of publication citations.

STUDY SELECTION AND DATA EXTRACTION:

All articles retrieved through the literature search and reference review were evaluated for inclusion in this review.

DATA SYNTHESIS:

Heterogeneously glycopeptide-intermediate S. aureus (hGISA) has been shown to significantly complicate treatment for patients with bacteremia and often escapes detection in clinical laboratories. Population analysis profile area under the curve ratio (PAP-AUC) is considered to be the gold standard of hGISA detection; however, it is labor-intensive, expensive, and not feasible in a clinical setting. The Etest macromethod is a reasonable alternative to PAP, yielding high sensitivity and specificity, and has potential for routine use in clinical laboratories. Due to these difficulties in detection, an exact prevalence is difficult to obtain though, based on available data, it appears that approximately 5-15% of isolates display this phenotype. hGISA is associated with prolonged bacteremia, high bacterial load infections, prolonged antibiotic therapy, prolonged hospitalization, treatment failure, and potential for increased mortality.

CONCLUSIONS:

Overall, hGISA is associated with a poor clinical course in patients with bacteremia. Information is still lacking regarding the actual prevalence of hGISA as well as the extent of its clinical impact. A uniform method of diagnosis must be established in order to better account for all cases of hGISA. More studies must be conducted to assess clinical outcomes of hGISA.