Extensive contact tracing and screening to control the spread of vancomycin-resistant Enterococcus faecium ST414 in Hong Kong

BACKGROUND

Proactive infection control management is crucial in preventing the introduction of multiple drug resistant organisms in the healthcare setting. In Hong Kong, where vancomycin-resistant enterococci (VRE) endemicity is not yet established, contact tracing and screening, together with other infection control measures are essential in limiting intra- and inter-hospital transmission. The objective of this study was to illustrate the control measures used to eradicate a VRE outbreak in a hospital network in Hong Kong.

METHODS

We described an outbreak of VRE in a healthcare region in Hong Kong, involving a University affiliated hospital and a convalescent hospital of 1600 and 550 beds respectively. Computer-assisted analysis was utilized to facilitate contact tracing, followed by VRE screening using chromogenic agar. Multi-locus sequence typing (MLST) was performed to assess the clonality of the VRE strains isolated. A case-control study was conducted to identify the risk factors for nosocomial acquisition of VRE.

RESULTS

Between November 26 and December 17, 2011, 11 patients (1 exogenous case and 10 secondary cases) in two hospitals with VRE colonization were detected during our outbreak investigation and screening for 361 contact patients, resulting in a clinical attack rate of 2.8% (10/361). There were 8 males and 3 females with a median age of 78 years (range, 40 - 87 years). MLST confirmed sequence type ST414 in all isolates. Case-control analysis demonstrated that VRE positive cases had a significantly longer cumulative length of stay (P < 0.001), a higher proportion with chronic cerebral and cardiopulmonary conditions (P = 0.001), underlying malignancies (P < 0.001), and presence of urinary catheter (P < 0.001), wound or ulcer (P < 0.001), and a greater proportion of these patients were receiving β-lactam/β-lactamase inhibitors (P = 0.009), carbapenem group (P < 0.001), fluoroquinolones (P = 0.003), or vancomycin (P = 0.001) when compared with the controls.

CONCLUSION

Extensive contact tracing and screening with a "search-and-confine" strategy was a successful tool for outbreak control in our healthcare region.

Long-term control of vancomycin-resistant Enterococcus faecium at the scale of a large multihospital institution: a seven-year experience

Repeated outbreaks of vancomycin-resistant Enterococcus faecium (VRE) occurred between 2004 and 2010 in Assistance Publique--Hôpitaux de Paris (AP-HP), a 23,000-bed multi-hospital institution. From August 2004 to December 2005, the French guidelines for preventing cross-transmission of multiresistant bacteria were applied. Because the number of VRE cases continued to increase, an institutional control programme was implemented from January 2006 onwards: it foresees stopping transfer of VRE and contact patients, separating VRE and contact patients in distinct cohorts, intervention of a central infection control team to support local teams, and quick application of measures as soon as first VRE cases are identified. Between August 2004 and December 2010, 45 VRE outbreaks occurred in 21 of the 38 AP-HP hospitals, comprising 533 cases. Time series analysis showed that the mean number of cases increased by 0.8 cases per month (95% confidence interval (CI): 0.3 to 1.3, p=0.001) before, and decreased by 0.7 cases per month after implementation of the programme (95% CI: -0.9 to -0.5, p<0.001), resulting in a significant trend change of -1.5 cases per month (95% CI: -2.1 to -0.9, p<0.001). The number of cases per outbreak was significantly lower after implementation of the programme. A sustained and coordinated strategy can control emerging bacteria at the level of a large regional multihospital institution.

Effectiveness of bivalent vaccines against Aeromonas hydrophila and Lactococcus garvieae infections in rainbow trout Oncorhynchus mykiss (Walbaum)

Lactococcus garvieae and Aeromonas hydrophila are bacterial pathogens affecting salmonids and other fish species and cause of heavy losses in aquaculture. Diseases caused by these bacteria can be controlled satisfactory by immunization using monovalent vaccines. In this study, the protective efficacy of two bivalent vaccines against L. garvieae and A. hydrophila was evaluated in rainbow trout (Oncorhynchus mykiss). Bivalent formulations, containing formalin-inactivated bacteria, were prepared as an aqueous bacterin and as an adjuvanted vaccine using montanide ISA-763. Protection against L. garvieae and A. hydrophila was tested at day 30 and 90 post-vaccination. High levels of protection were achieved for the aqueous and adjuvanted bivalent vaccines against L. garvieae (RPS of 100% and 95.3%) and A. hydrophila (RPS of 100% and 95.3%) at day 30 post-vaccination. Significant differences (p < 0.05) were found between the RPS at days 30 and 90 post-immunization with a decrease in the protection levels for the aqueous bivalent vaccine against L. garvieae (RPS 76.2%) and A. hydrophila (RPS 85%), but not for the adjuvanted vaccine (RPS of 90% against L. garvieae and 95% against A. hydrophila). In addition, high antibody levels were observed in the vaccinated fish at day 15 post-immunization using both vaccines. Our results demonstrate that these bivalent vaccines can effectively protect rainbow trout against L. garvieae and A. hydrophila and could offer an appropriate strategy to prevent these infections in rainbow trout farms.

[Experience of bicillin prevention of acute respiratory diseases in the training center]

The article describes the experience of emergency prevention of acute respiratory diseases among the young recruits by intramuscular injection of BICILLIN-5. This method allowed in winter 2011 to reduce the number of diseases caused by pneumococcus, staphylococcus and streptococcus significantly. Considering the polyetiology of pneumonia, acute bronchitis and acute respiratory infections, the lack of specific means of prevention against the majority of them, as well as the role of the low resistance of the organism in the military development of acute respiratory diseases, it is proposed to use antiviral drugs and immunotropic funds in addition to chemoprophylaxis and vaccination.

Antibiotic prophylaxis for bacterial infections in afebrile neutropenic patients following chemotherapy

BACKGROUND

Bacterial infections are a major cause of morbidity and mortality in patients who are neutropenic following chemotherapy for malignancy. Trials have shown the efficacy of antibiotic prophylaxis in reducing the incidence of bacterial infections but not in reducing mortality rates. Our systematic review from 2006 also showed a reduction in mortality.

OBJECTIVES

This updated review aimed to evaluate whether there is still a benefit of reduction in mortality when compared to placebo or no intervention.

SEARCH METHODS

We searched the Cochrane Cancer Network Register of Trials (2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 2, 2011), MEDLINE (1966 to March 2011), EMBASE (1980 to March 2011), abstracts of conference proceedings and the references of identified studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs comparing different types of antibiotic prophylaxis with placebo or no intervention, or another antibiotic, to prevent bacterial infections in afebrile neutropenic patients.

DATA COLLECTION AND ANALYSIS

Two authors independently appraised the quality of each trial and extracted data from the included trials. Analyses were performed using RevMan 5.1 software.

MAIN RESULTS

One-hundred and nine trials (involving 13,579 patients) that were conducted between the years 1973 to 2010 met the inclusion criteria. When compared with placebo or no intervention, antibiotic prophylaxis significantly reduced the risk of death from all causes (46 trials, 5635 participants; risk ratio (RR) 0.66, 95% CI 0.55 to 0.79) and the risk of infection-related death (43 trials, 5777 participants; RR 0.61, 95% CI 0.48 to 0.77). The estimated number needed to treat (NNT) to prevent one death was 34 (all-cause mortality) and 48 (infection-related mortality).Prophylaxis also significantly reduced the occurrence of fever (54 trials, 6658 participants; RR 0.80, 95% CI 0.74 to 0.87), clinically documented infection (48 trials, 5758 participants; RR 0.65, 95% CI 0.56 to 0.76), microbiologically documented infection (53 trials, 6383 participants; RR 0.51, 95% CI 0.42 to 0.62) and other indicators of infection.There were no significant differences between quinolone prophylaxis and TMP-SMZ prophylaxis with regard to death from all causes or infection, however, quinolone prophylaxis was associated with fewer side effects leading to discontinuation (seven trials, 850 participants; RR 0.37, 95% CI 0.16 to 0.87) and less resistance to the drugs thereafter (six trials, 366 participants; RR 0.45, 95% CI 0.27 to 0.74).

AUTHORS' CONCLUSIONS

Antibiotic prophylaxis in afebrile neutropenic patients significantly reduced all-cause mortality. In our review, the most significant reduction in mortality was observed in trials assessing prophylaxis with quinolones. The benefits of antibiotic prophylaxis outweighed the harm such as adverse effects and the development of resistance since all-cause mortality was reduced. As most trials in our review were of patients with haematologic cancer, we strongly recommend antibiotic prophylaxis for these patients, preferably with a quinolone. Prophylaxis may also be considered for patients with solid tumours or lymphoma.

[Criteria of antibacterials choice for prophylaxis and therapy of implant-associated infections in prosthetic joints]

Prosthetic joints infection is a serious medical, social and financial problem. Significant achievements in prophylaxis of such infections are well known. In cases of primary endoprosthetics of large joints, the frequency of infection in the leading world clinics is 0.5-2%. However, the approaches to the treatment of such infections are different especially with respect to the antibacterial therapy: choice of drugs, administration routes, treatment course and discontinuation. Under conditions of global growth of resistance in nosocomial pathogens, the choice of antimicrobials requires consideration not only of the formal susceptibility criteria, but also of the pharmacokinetic and pharmacodynamic indices.

Expression of immune-related genes in rainbow trout (Oncorhynchus mykiss) induced by probiotic bacteria during Lactococcus garvieae infection

The aim of the present study was to investigate the effect of lactic acid bacteria (LAB) on the control of lactococcosis as well as to assess the impact of probiotics on the expression of immune-related genes in the head kidney and intestine of rainbow trout (Oncorhynchus mykiss). Lactobacillus plantarum, Lactococcus lactis and Leuconostoc mesenteroides, were administered orally at 10⁶ CFU g⁻¹ feed to fish for 36 days. Twenty-one days after the start of the feeding period, fish were challenged with Lactococcus garvieae. Only the fish fed the diet containing Lb. plantarum showed significantly (P < 0.05) improved protection against L. garvieae compared to the control. Subsequently, real-time PCR was employed to determine the mRNA levels of IL-1β, IL-8, IL-10 and TNF-α in the head kidney, and IL-8, Tlr5 and IgT in the intestine of the control and Lb. plantarum groups. IL-1β, IL-10 and TNF-α gene expression were significantly up-regulated by Lb. plantarum. Moreover, the mRNA levels of IL-10, IL-8 and IgT were significantly higher in the Lb. plantarum group after L. garvieae infection, suggesting that Lb. plantarum can stimulate the immune response of rainbow trout. PCR-DGGE revealed no detectable levels of the probiotics or the pathogen present on the distal intestinal mucosa. These findings demonstrate that direct probiotic-host interactions with the intestine are not always necessary to induce host stimulatory responses which ultimately enhance disease resistance. Furthermore, as L. garvieae did not colonise the intestinal tract, and therefore likely did not infect via this route, the antagonistic properties of the probiotic candidate towards L. garvieae were likely of little influence in mediating the improved disease resistance which could be attributed to the elevated immunological response.

[Investigation of the efficacy of some disinfectants against nosocomial Staphylococcus aureus and Enterococcus spp. isolates]

Nosocomial infections which exhibit an increasing trend worldwide, are important contributors to morbidity and mortality. Most bacteria that cause nosocomial infections can retain their viability even after exposure to disinfectants in routine practice. This study was conducted to determine the susceptibilities of nosocomial Staphylococcus aureus and Enterococcus spp. isolates to various disinfectants. A total of 30 S.aureus [16 were methicillin-resistant (MRSA), 14 were methicillin-susceptible (MSSA)] and 21 Enterococcus spp. (13 E.faecalis, 7 E.faecium, 1 non-typable Enterococcus spp.) strains isolated from clinical samples of hospitalized patients as nosocomial infection agents in the Central Microbiology Laboratory of Ibn-i Sina Hospital, Ankara University, Faculty of Medicine, were included in the study. Glutaraldehyde (2% wt/vol), chlorhexidine gluconate (4% wt/vol), 2-propanol (70% vol/vol), povidone iodine (7.5% wt/vol), povidone iodine (10% wt/vol) and hydrogen peroxide (3% wt/vol) susceptibilities of the isolates were investigated by quantitative suspension test at contact times of 3, 5, and 10 minutes. All of the isolates were found susceptible to glutaraldehyde (2%), chlorhexidine gluconate (4%), povidone iodine (7.5%), povidone iodine (10%) and 2-propanol (70%) at all tested contact times. However, 12 S.aureus (5 MSSA, 7 MRSA) and 3 enterococci (2 E.faecium, 1 E.faecalis) isolates were found susceptible to hydrogen peroxide (3%) at 3 minutes contact time; 11 S.aureus (4 MSSA, 7 MRSA) and 7 E.faecalis isolates were found susceptible at 5 minutes contact time, and 6 S.aureus (4 MSSA, 2 MRSA) and 3 enterococci (1 E.faecium, 2 E.faecalis) isolates were found susceptible at 10 minutes contact time. One MSSA and 8 enterococci (4 E.faecium, 3 E.faecalis, 1 Enterococcus spp.) isolates were found resistant to hydrogen peroxide (3%) at 10 minutes contact time. In conclusion, glutaraldehyde (2%), chlorhexidine gluconate (4%), povidone iodine (7.5%), povidone iodine (10%) and 2-propanol (70%) can be safely used against S.aureus and Enterococcus spp. owing to their high effectiveness, however, hydrogen peroxide (3%) should not be preferred against those strains due to the presence of resistant isolates, in Ankara University Ibn-i Sina Hospital.

Intervention to reduce transmission of resistant bacteria in intensive care

BACKGROUND

Intensive care units (ICUs) are high-risk settings for the transmission of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococcus (VRE).

METHODS

In a cluster-randomized trial, we evaluated the effect of surveillance for MRSA and VRE colonization and of the expanded use of barrier precautions (intervention) as compared with existing practice (control) on the incidence of MRSA or VRE colonization or infection in adult ICUs. Surveillance cultures were obtained from patients in all participating ICUs; the results were reported only to ICUs assigned to the intervention. In intervention ICUs, patients who were colonized or infected with MRSA or VRE were assigned to care with contact precautions; all the other patients were assigned to care with universal gloving until their discharge or until surveillance cultures obtained at admission were reported to be negative.

RESULTS

During a 6-month intervention period, there were 5434 admissions to 10 intervention ICUs, and 3705 admissions to 8 control ICUs. Patients who were colonized or infected with MRSA or VRE were assigned to barrier precautions more frequently in intervention ICUs than in control ICUs (a median of 92% of ICU days with either contact precautions or universal gloving [51% with contact precautions and 43% with universal gloving] in intervention ICUs vs. a median of 38% of ICU days with contact precautions in control ICUs, P<0.001). In intervention ICUs, health care providers used clean gloves, gowns, and hand hygiene less frequently than required for contacts with patients assigned to barrier precautions; when contact precautions were specified, gloves were used for a median of 82% of contacts, gowns for 77% of contacts, and hand hygiene after 69% of contacts, and when universal gloving was specified, gloves were used for a median of 72% of contacts and hand hygiene after 62% of contacts. The mean (±SE) ICU-level incidence of events of colonization or infection with MRSA or VRE per 1000 patient-days at risk, adjusted for baseline incidence, did not differ significantly between the intervention and control ICUs (40.4±3.3 and 35.6±3.7 in the two groups, respectively; P=0.35).

CONCLUSIONS

The intervention was not effective in reducing the transmission of MRSA or VRE, although the use of barrier precautions by providers was less than what was required. (Funded by the National Institute of Allergy and Infectious Diseases and others; STAR*ICU ClinicalTrials.gov number, NCT00100386.).

[Analysis of nosocomial pediatric bacteremias at a general hospital between 1990 and 2006. The impact of attending the intravascular therapy]

INTRODUCTION

The administration of parenteral infusates is a frequent intervention that is considered innocuous; moreover, the risk of this procedure which offers a direct access to the bloodstream is minimized.

OBJECTIVE

To evaluate the epidemiology of nosocomial pediatric bacteremias after implementing a control program.

METHODS

Analysis of pediatric bacteremias was made in 3 periods: 1) 1990-1992, prior to establishing strategies to avoid contamination of parenteral infusions; 2) 1996, the phase after establishing these strategies; and 3) 2005-2006, the recent situation in the hospital.

RESULTS

The proportion of gram-negative rods isolated in blood cultures dropped from 82.9 to 35.1% (p = 0.004) during the 17-year study period. There was no significant difference in the proportion of gram-negative rods isolated from intravascular catheters. The proportion of contaminated parenteral infusions dropped from 22.2% to 0.4% (p < 0.001).

DISCUSSION

The strategies established to avoid the contamination of parenteral infusions were associated with a reduction in the proportion of gram-negative rods in blood cultures, although the proportion is still higher than that in developed countries, probably related to catheter contamination. We suggest establishing similar strategies in other hospitals from developing countries.

Hospital-acquired infections and leading pathogens detected in a regional university adult acute-care hospital in Genoa, Liguria, Italy: results from a prevalence study

BACKGROUND

A prevalence study aimed to update the epidemiological scenario of Hospital-Acquired Infections (HAI) was performed at the San Martino University Hospital of Genoa, the Regional Reference Adult-care Center in Liguria, Italy, with more than 1300 beds.

MATERIALS AND METHODS

The investigation was performed in all the wards, except the Psychiatric Units, between 19th March and 6Ih April, 2007, using a one-day monitoring system for each ward. International standardized criteria and definitions for the surveillance of HAI were used for the collection of data, which were recorded in specific software for subsequent consolidation, analysis and quality control.

RESULTS

The hospital infection control staff actively monitored 912 inpatients: a total of 84 HAI among 72 patients were diagnosed, with an overall prevalence of infections and affected cases of 9.2% (95% CI: 7.3-11.1) and 7.9% (95% CI: 6.1-9.7), respectively. Urinary Tract Infections (UTI) (30.9%), Respiratory Tract Infections (RTI) (28.6%) and Blood Stream Infections (BSI) (21.4%) were found to be the most frequent infections. As expected, both specific prevalence and localization of HAI varied considerably between wards, with the highest values recorded in Intensive Care Units (ICU) and in Functional Rehabilitation wards. RTI (26.3%) and BSI (13.2%) were found primarily represented in ICU, while the highest values of UTI (13.3%) were registered in Functional Rehabilitation Units. Enterococcus spp. (16.8%), Candida spp. (14%), Pseudomonas spp. (12.2), Staphylococcus aureus (10.7%), Escherichia coli (10.3%) and Coagulase-negative staphylococci (CNS) (9.3%) were the most frequent pathogens isolated. The overall rate of administration of antibiotics was 55.3% and penicillin (26.7%), cephalosporins (22.8%) and fluoroquinolones (17.9%) were found to be the leading antibacterial administered.

CONCLUSION

Results of the present study have been, and are currently, used for orientating surveillance and control hospital policies, planning activities according to a rational and evidence-based approach.

[Antibiotic resistance of Gram-positive cocci isolated in 2008]

OBJECTIVE

Antibiotic resistance evaluation of Gram-positive cocci isolated in 2008.

MATERIAL AND METHODS

Antibiotic susceptibility testing was performed for 1044 strains: 610 Staphylococcus aureus (352 from patients, 258 from carriers), 203 Streptococcus pneumoniae (53 from patients, 150 from carriers), 144 Enterococcus faecalis. 57 Enterococcus faecium and 30 Streptococcus spp. using automatic systems Vitek 2 Compact. MicroScan, disc diffusion method and Etest according to 2008 CLSI. A number of 497 Streptococcus pyogenes strains were tested for eritromycin resistance.

RESULTS

There were 33.2% MRSA for strains isolated from patients and 30.0% from carriers. From MRSA strains. 35.5% were resistant to gentamicin. 33.6% to ciprofloxacin, 74.3% to erythromycin and 30.5% to rifampin. There were no S. aureus strain resistant to vancomycin and linezolid. S. aureus strains isolated from wounds were more resistant to erythromycin (43.9%) than the strains isolated from systemic infections (12.1%). From 11 S. pneumoniae strains isolated from meningitis, 4 were resistant to penicillin. Neither S. pneumoniae strain isolated from other infections, nor those from carriers had MIC to penicillin more than 4 microg/ml. S. pneumoniae strains isolated from carriers were more resistant to erythromycin. clindamycin and tetracycline than the strains isolated from patients (66.7%, 54.1%, 54.2% vs. 27.4%, 22.6%, 33.9%). E. faecium was 95.9% resistant to penicillin, 90.2% to ampicillin, 64.7% to gentamicin, 72.0% to streptomycin and 78.4% to ciprofloxacin. F. faecalis was less resistant than E. faecium at most of the antibiotics: 32.4% to gentamicin, 59.6% to streptomycin, 28.5% to ciprofloxacin. Viridans group Streptococci, all isolated from blood culture were 92% susceptible to penicillin and ampicillin. To erythromycin, 12% of viridians group Streptococci were resistant. S. pyogenes resistance to eritromycin was 5.8%.

CONCLUSIONS

S. aureus strains showed a relatively high level of resistance to oxacillin (33.2%) and resistance in the same time to several antibiotics. S. pneumoniae can not be considered resistant to penicillin administrated parenteral, with exception of the strains isolated from meningitis. E. faecium had a higher resistance rate than E. faecalis.

Enhancing patient safety by reducing healthcare-associated infections: the role of discovery and dissemination

Healthcare-associated infections (HAIs) take a major human toll on society and reduce public confidence in the healthcare system. The current convergence of scientific, public, and legislative interest in reducing rates of HAI can provide the necessary momentum to address and answer important questions in HAI research. This position paper outlines priorities for a national approach to HAIs: scrutinizing the science base, developing a prioritized research agenda, conducting studies that address the questions that have been identified, creating and deploying guidelines that are based on the outcomes of these studies, and then initiating new studies that assess the efficacy of the interventions.

A noninvasive near infrared system for detection of platelet components contaminated with bacteria

BACKGROUND

Platelet (PLT) transfusion-associated bacterial sepsis has remained a substantial patient risk, primarily due to lacking effective and point-of-issue measures to detect bacterial contamination. This study describes near infrared (NIR) spectroscopy to examine inoculated PLTs without sampling within a few seconds.

STUDY DESIGN AND METHODS

This study evaluated apheresis PLTs inoculated with low concentrations of Bacillus cereus and Staphylococcus epidermidis, comparing with sterile bags. Short-wavelength NIR spectra over the range from 700 to 1100 nm in the transmittance mode were obtained using research (NIRS6500, Foss NIRSystems) and portable (NIRGun, Shizuoka Shibuya Seiki) instruments at 6-hour intervals from 0 to 72 hours after inoculation (HAI).

RESULTS

The sensitivity of the NIRS6500 was 100% (43/43) and 98% (50/51) after incubating PLTs inoculated with B. cereus for 42 HAI or more and with S. epidermidis for 54 HAI or more, respectively. Difference spectra calculated by subtracting the NIR spectra of stored PLTs with that of the same PLTs measured at 0 HAI improved the discrimination results compared with conventional second derivative spectra.

CONCLUSION

The NIRS6500 system can provide a PLT monitoring system based on difference spectra. The chemical components of PLTs that were influenced by bacterial metabolism seemed to play an important role in the calibration structure. Further studies should examine samples spiked with various species of prevalent bacteria.

[Antibiotic therapy by suppurative diseases of the abdominal cavity and soft tissues]

Microbial background of the departments of abdominal and septic surgery was monitored and analyzed. More the 950 samples from each department was worked out. Therefore, it was determined, that gram-negative bacteria were more typical for the abdominal pathology, whereas, soft tissue infection was represented by gram-positive strains. Compliant antibioticogramms were performed and analyzed. For achieving effective prophylactic and empiric antibiotic therapy, data-based formular lists of antibacterial drugs were performed.

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.

Antimicrobial activity in the tick Rhipicephalus (Boophilus) microplus eggs: Cellular localization and temporal expression of microplusin during oogenesis and embryogenesis

Arthropods display different mechanisms to protect themselves against infections, among which antimicrobial peptides (AMPs) play an important role, acting directly against invader pathogens. We have detected several factors with inhibitory activity against Candida albicans and Micrococcus luteus on the surface and in homogenate of eggs of the tick Rhipicephalus (Boophilus) microplus. One of the anti-M. luteus factors of the egg homogenate was isolated to homogeneity. Analysis by electrospray mass spectrometry (ESI-MS) revealed that it corresponds to microplusin, an AMP previously isolated from the cell-free hemolymph of R. (B.) microplus. Reverse transcription (RT) quantitative polymerase chain reactions (qPCR) showed that the levels of microplusin mRNA gradually increase along ovary development, reaching an impressive highest value three days after the adult females have dropped from the calf and start oviposition. Interestingly, the level of microplusin mRNA is very low in recently laid eggs. An enhance of microplusin gene expression in eggs is observed only nine days after the onset of oviposition, achieving the highest level just before the larva hatching, when the level of expression decreases once again. Fluorescence microscopy analysis using an anti-microplusin serum revealed that microplusin is present among yolk granules of oocytes as well as in the connecting tube of ovaries. These results, together to our previous data, suggest that microplusin may be involved not only in protection of adult female hemocele, but also in protection of the female reproductive tract and embryos, what points this AMP as a considerable target for development of new methods to control R. (B.) microplus as well as the vector-borne pathogens.

[Risk factors associated to vancomycin-resistant enterococccus colonization in the Army Hospital in Santiago]

Since the appearance of Vancomicin-resistant enterococci (VRE) in our country, the Chilean Ministry of Health recommended the surveillance of intestinal colonization in patients in critical wards. We report the results of surveillance in ICU and onco-hematological wards from 2002 to 2008, with analysis of possible risk factors: demographical data, use and type of antibiotic, days of hospitalization prior to sampling, and year of hospitalization. Colonization rate increased from 0.03 cases per 1000 bed-days in 2003 to 0.18 cases during 2008. Univariate analysis identified 7 risk factors associated with ERV colonization: hospitalization in ICU, use of antibiotics, use of 3 or more compounds, use of imipenem or colistin, >10 days of hospitalization prior to the study and year of hospitalization (before 2007 or after). Multivariate analysis by logistic binary regression showed that only the last two: >10 days of hospitalization prior to the study and year of hospitalization (before 2007 or after), were significantly associated to colonization by ERV.

Exit-site care in Austrian peritoneal dialysis centers -- a nationwide survey

BACKGROUND

Catheter-associated infections markedly contribute to treatment failure in peritoneal dialysis (PD) patients. There is much controversy surrounding prophylactic strategies to prevent these infections.

METHODS

In this nationwide multicenter study we analyzed strategies to prevent catheter-associated infections as performed in Austrian PD centers in 2006. A questionnaire was sent to all 23 PD centers in Austria.

RESULTS

Ten different catheter models were used in the 332 patients being treated in the 23 Austrian PD centers. Systemic antibiotics prior to catheter placement were given by 17 of the 23 PD centers (glycopeptides, n = 7; cephalosporins, n = 10). Nasal swabs were taken preoperatively by 17 PD centers; nasal Staphylococcus aureus carriers were treated prophylactically with mupirocin cream in 15 of these centers. Dressing change was routinely performed in 318 of 332 chronic PD patients (nonocclusive film dressing, n = 58; gauze dressing, n = 260). Disinfectants for chronic exit-site care included povidone iodine (n = 155), sodium hypochlorite (n = 31), povidone iodine + sodium hypochlorite together (n = 102), and octenidine dihydrochloride/phenoxyethanol (n = 17). Water + non-disinfectant soap or 0.9% sodium chloride was administered as a cleansing agent to the exit site by 27 patients. Routine S. aureus screening (nasal and/or exit-site swabs) in chronic PD patients was performed in 12 PD centers; carriers were treated with mupirocin cream in 11 of these centers. Dialysis staff members were screened for S. aureus in 8 PD centers and spouses were screened for S. aureus in 5 PD centers. The overall exit-site infection rate was 1 episode/43.9 patient-months, tunnel infection rate was 1 episode/88.9 patient-months, and peritonitis rate was 1 episode/51.0 patient-months. Patients of centers that have installed a prophylaxis protocol for treating S. aureus carriers had lower mean infection rates compared with those not using such a protocol.

CONCLUSION

Various individual prophylactic strategies are used to prevent catheter-associated infections in Austrian PD centers. Infection rates are within the range reported in the literature. There is still scope for improvement in some centers (e.g., by establishing a prophylaxis protocol).