Emergence of Vancomycin-Resistant Enterococci in San Francisco Bay Area Hospitals During 1994 to 1998

Nosocomial infections caused by vancomycin-resistant Enterococcus in a Japanese general hospital and molecular genetic analysis

INTRODUCTION

Vancomycin-resistant Enterococcus (VRE) is a rare bacterium in Japan, but an outbreak due to nosocomial transmission in medical facilities has been reported in recent years. Here, we report the outbreak of vanA vancomycin-resistant Enterococcus faecium (VREfm) in multiple wards of Nara Prefectural General Medical Center in 2019 and results of the molecular epidemiology analysis.

METHODS

An aggressive screening program was conducted after the first VREfm was detected in a patient in the A ward. During the outbreak, 6000 rectal swab samples were screened for VRE by culture. Isolates from 60 patients with VREfm detected were clustered using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST).

RESULTS

PFGE revealed a cluster consisting of three major clusters and four multi-strains. The first major cluster consisted of 26 isolates, the second consisted of 10 isolates, the third consisted of 6 isolates, and the remaining 4 clusters consisted of 2 isolates. MLST identified an allele profile (ST80) in most clusters of clone types P01-P06 but an allele profile (ST992) in cluster P07.

CONCLUSION

Based on the PFGE pattern, this case was considered to be a nosocomial infection due to multiple clones. Later, in addition to screening, sharing of hospital information, cohorting of patients and staff, and strengthening of environmental cleanup were carried out, and horizontal infection was suppressed.

Catecholamines increase conjugative gene transfer between enteric bacteria

The ability of pathogenic bacteria to sense and respond to periods of host stress is critical to their lifestyle. Adrenaline and norepinephrine are catecholamines that mediate acute host stress in vertebrates and invertebrates. Catecholamines are also used as environmental cues to enhance growth, motility and virulence of bacterial pathogens via specific binding receptors. Incidence of multidrug resistant and highly virulent bacterial pathogens is on the rise, and majority of the genes for antimicrobial resistance (AMR) and virulence are carried on horizontally transferable genetic elements. Conjugation machinery offers an efficient method for acquisition of AMR and virulence genes, which may be responsible for propelling the evolution of pathogenic bacteria. Here we show that norepinephrine (NE) at physiological concentrations enhances horizontal gene transfer (HGT) efficiencies of a conjugative plasmid from a clinical strain of Salmonella Typhimurium to an Escherichia coli recipient in vitro. Expressions of plasmid encoded transfer (tra) genes necessary for conjugation were also significantly upregulated in the presence of NE. Phentolamine, an α-adrenergic receptor antagonist, negated the effects of NE on conjugation more strongly than propranolol, a β-adrenergic receptor antagonist. This study for the first time provides evidence that innate mediators of acute host stress may influence evolution and adaptation of bacterial pathogens.

Impact of antimicrobial stewardship program on vancomycin use in a pediatric teaching hospital

BACKGROUND

Increasing rates of resistant gram-positive coccal infections led to an increased use of vancomycin. We evaluated the impact of implementing an Antimicrobial Stewardship Program on density of vancomycin use at a pediatric tertiary-care teaching hospital.

METHODS

An Antimicrobial Stewardship Program was implemented April 1, 2004. Indications for vancomycin use were incorporated as mandatory fields using the integrated computerized information system. An automated report of vancomycin prescriptions, doses, patient demographics, and microbiology data was reviewed by an infectious disease pharmacist Monday through Friday. Interventions were discussed with a pediatric infectious disease physician and real-time feedback provided to clinicians. Density of vancomycin use was evaluated by measuring the number of doses administered/1000 patient-days.

RESULTS

Density of vancomycin use declined overtime from 378 doses administered/1000 patient-days to 255 doses administered/1000 patient-days despite increasing rates of Staphylococcus aureus infected patients, and was not associated with increased use of other antibiotics with similar antimicrobial activity. Nonapproved vancomycin indications were selected in 28% of vancomycin doses administered. Of the 317 Antimicrobial Stewardship Program interventions performed, 190 qualified as vancomycin prescription errors, most commonly, vancomycin dosing and premature stop. After the implementation of the program, the rate of vancomycin prescription errors decreased.

CONCLUSIONS

Implementation of an integrated Antimicrobial Stewardship Program using real-time evaluation and feedback to physicians, and optimization of the clinical informatics system, reduced vancomycin utilization and vancomycin prescribing errors, improving the quality of care and safety of hospitalized children in our institution.

Diagnostic microarray for human and animal bacterial diseases and their virulence and antimicrobial resistance genes

Rapid diagnosis and treatment of disease is often based on the identification and characterization of causative agents derived from phenotypic characteristics. Current methods can be laborious and time-consuming, often requiring many skilled personnel and a large amount of lab space. The objective of our study was to develop a spotted microarray for rapid identification and characterization of bacterial pathogens and their antimicrobial resistance genes. Our spotted microarray consists of 489 70mer probes that detect 40 bacterial pathogens of medical, veterinary and zoonotic importance (including 15 NIAID Category A, B and C pathogens); associated genes that encode resistance for antimicrobial and metal resistance; and DNA elements that are important for horizontal gene transfer among bacteria. High specificity and reliability of the microarray was achieved for bacterial pathogens of animal and human importance by validating MDR pathogenic bacteria as pure cultures or by following their inoculation in complex and highly organic sample matrices, such as soil and manure.

Isolation and identification of enterococci from seawater samples: assessment of their resistance to antibiotics and heavy metals

A hundred Enterococcus strains were isolated from seawater samples collected from coastal areas of Istanbul. Isolates were identified to the species level using standard biochemical tests specified by Facklam and Collins. The species distribution was as follows Enterococcus faecalis (96%), Enterococcus gallinarum (3%) and Enterococcus solitarius (1%). The resistance of bacteria to both heavy metals (zinc [Zn], iron [Fe], cadmium [Cd], chrome [Cr], cobalt [Co]) and antibiotics (ampicillin 10 microg [AP], penicillin G 10 Units [PG], gentamycin 10 microg [GM], streptomycin 10 microg [S], chloramphenicol 10 microg [C], erythromycin 15 microg [E], kanamycin 30 microg [K], amikacin 30 microg [AK], nalidixic acid 30 microg [NA], and vancomycin 30 microg [VA]) was evaluated. None of the strains was resistant to VA. It was found that among the 100 isolates, those that exhibit resistance to antibiotics, particularly NA, S and K, were also resistant all the heavy metals tested. To our knowledge this is the first report focusing on determination of resistance of environmental enterococci found in Istanbul against heavy metals and antibiotics. Thus, combined expressions of antibiotic and heavy metal resistance may help to reinforce ecological and epidemiological studies and to determine the role of these strains in antibiotic and heavy metal resistance dissemination.

[Incidence of vancomycin-resistant Enterococcus at a university hospital in Brazil]

OBJECTIVE

Vancomycin-resistant Enterococcus (VRE) is today one of the principal microorganisms implicated in nosocomial infections. Thus, a study was carried out with the objective of evaluating its epidemiology at a tertiary-level teaching hospital.

METHODS

This was a three-year retrospective epidemiological study conducted from 2000 to 2002. Samples of VRE-positive clinical cultures at a 660-bed university hospital were analyzed. The incidence of VRE and the main anatomical sites and hospital units from which it was isolated were defined. Differences between the variables over the three years of the study were verified, and these were considered significant when p<0.05.

RESULTS

There was a progressive increase in the vancomycin resistance in the clinical cultures that were positive for Enterococcus spp., over the three years of the study. In 2000, 9.5% of the samples were vancomycin-resistant, and this increased to 14.7% in 2001 and 15.8% in 2002. The hospital units with the largest numbers of isolates were, respectively, the emergency ward (19.5%) and the general intensive care unit (15%). The anatomical sites with the highest amounts of isolates included: urine (36%) and blood (20%).

CONCLUSIONS

With the progressive increase in the incidence of vancomycin resistance and the VRE rate, it is concluded that more effective control measures are needed for deterring the dissemination of VRE.

The state of the science of health care epidemiology, infection control, and patient safety, 2004

Being aware and implementing the latest and best scientific evidence in infection control and health care epidemiology is critical to enhancing patient outcomes. In this review, the latest published scientific data in health care epidemiology and patient safety were reviewed for the period May 2003-May 2004. Medline reviews and reviews of infection control and infectious diseases journals were used for this period. The latest guidelines and publications on antimicrobial resistance, nursing or infection control professional staffing, West Nile virus, and Severe Acute Respiratory Syndrome (SARS) are included. Awareness of these and other important infection control publications is essential if the latest measures are to be implemented to prevent and control health care-associated infections.