Multiresistant Pseudomonas aeruginosa outbreak in a pediatric oncology ward related to bath toys

Less restrictions in daily life: a clinical practice guideline for children with cancer

PURPOSE

In current clinical practice, recommendations regarding restrictions in daily life for children with cancer are often lacking or not evidence-based. Critically reviewing the evidence and formulating recommendations are therefore of great importance as social restrictions (e.g., swimming, school attendance, sports) can impair the quality of life of these children severely. Therefore, our aim was to develop a clinical practice guideline for clinicians, children, and their parents regarding social restrictions in children with cancer.

METHODS

A comprehensive multidisciplinary panel was assembled, comprising 21 professionals and patient representatives. A systematic literature review was performed, including dual appraisal of all citations. The GRADE methodology was used to extract, summarize, and assess the evidence. Multiple in-person meetings were held to rank outcomes, discuss evidence, complete evidence-to-decision frameworks, and formulate recommendations. Final recommendations were unanimously supported by all panel members.

RESULTS

Six studies, including 758 children, formed the evidence base for the recommendations. Given the scarcity of the available evidence and various designs of studies in children with cancer, additional evidence was extracted from adult oncology guidelines, and shared expert opinions were utilized. In total, 14 recommendations were formulated of which multiple result in changes in current policy and standard of practice in the Netherlands. Topics covered in this guideline are swimming, having pets, visiting the zoo or farm, performing sports or high-velocity events, attending school or kindergarten, and use of public transport. This guideline is not intended to provide recommendations for patients after end of treatment, for palliative care settings, or for children undergoing a stem cell transplantation.

CONCLUSIONS

In this clinical practice guideline, we provide recommendations regarding restrictions in daily life in children with cancer. These include evidence-based recommendations and, in the absence of sufficient evidence, recommendations based on expert evidence. With these recommendations, we provide guidance for clinicians, children, and parents and contribute to improving quality of life for children with cancer.

Microbial Adherence to Contact Lenses and Pseudomonas aeruginosa as a Model Organism for Microbial Keratitis

Microbial keratitis (MK), the infection of the cornea, is a devastating disease and the fifth leading cause of blindness and visual impairment around the world. The overwhelming majority of MK cases are linked to contact lens wear combined with factors which promote infection such as corneal abrasion, an immunocompromised state, improper contact lens use, or failing to routinely disinfect lenses after wear. Contact lens-related MK involves the adherence of microorganisms to the contact lens. Therefore, this review discusses the information currently available regarding the disease pathophysiology, the common types of microorganisms causing MK, physical and organic mechanisms of adhesion, material properties which are involved in adhesion, and current antimicrobial strategies. This review also concludes that Pseudomonas aeruginosa is a model organism for the investigation of contact lens microbial adherence due to its prevalence in MK cases, its extremely robust adhesion, antimicrobial-resistant properties, and the severity of the disease it causes.

Epidemiological investigation of Pseudomonas aeruginosa isolates including Multidrug-Resistant serogroup O12 isolates, by use of a rapid and simplified Multiple-Locus Variable-Number of Tandem Repeats Analysis and Whole Genome Sequencing

BACKGROUND

Clustered cases of Pseudomonas aeruginosa infection in immunocompromised patients' wards require rapid characterization of a potential epidemic to guide investigations and identify the potential source of contamination.

AIM

To design and evaluate a rapid and simple typing method for P. aeruginosa in comparison to whole genome sequencing (WGS).

METHODS

We designed and used a simplified PCR based on multiple locus tandem variable number analysis (MLVA) to investigate cases of P. aeruginosa infection and colonization in a paediatric haematology department. The method was compared to WGS by using Illumina method.

FINDINGS

On the 17 isolates recovered from 15 children (8 from blood cultures, 3 from urinary tract infections, 1 from sputum and 5 stool isolates) MLVA distinguished 10 different profiles and 7 isolates from 6 children shared the same profile. Analysis by WGS revealed that these 7 isolates belonged to sequence type ST111 and serotype O12 and permitted to further distinguish at least 3 different genotypes among them. Five environmental strains had 3 MLVA profiles, one shared with a clinical isolate but WGS excluded any relationship.

CONCLUSION

The simplified and inexpensive MLVA method permitted to exclude, in less than five hours, most of unrelated isolates and to focus investigations on a small number of cases while WGS, taking several days of work, drew definitive conclusions concerning the outbreak and the genetic relationships of the ST111 isolates circulating in the department. We conclude that sequential use of both methods is the optimal strategy to investigate grouped cases of P. aeruginosa infections.

Toys in the Playrooms of Children’s Hospitals: A Potential Source of Nosocomial Bacterial Infections?

Pediatric patients are more susceptible and vulnerable to nosocomial infections, in part because of their nascent and developing immune system and in part due to certain congenital conditions. Consequently, we found limited literature that investigated and reported children’s toys in hospital playrooms as potential reservoirs of pathogenic microbes. Hence, in the present study, we aimed to investigate toys as potential vectors for nosocomial infections in children’s hospitals. Microbiological samples from 120 toys were collected between April 2018 and November 2018. The specimens were cultivated on suitable cultivation agars for 24–72 h at 37 °C and CFU/cm2 (colony forming units) was determined. Antibiotic susceptibility testing was performed using disc diffusion and E-tests. Our results indicate that 84% of samples were contaminated with different microbes. Four distinct genera and thirty-seven species of bacteria were identified. The most frequently isolated pathogen was Sphingomonas paucimobilis (>603 CFU/cm2). Most of the identified microorganisms were members of normal human microbiota. Although Staphylococcus aureus and Acinetobacter baumannii were identified, CFU/cm2 was relatively low and they were found to be sensitive to antibiotics. Additionally, plastic toys showed the highest average CFU/cm2 of 91.9. Our results bolster the need for adoption and strict enforcement of proper disinfection techniques for toys in the hospital playrooms.

Environmental risks of Pseudomonas aeruginosa-What to advise patients and parents

Pseudomonas aeruginosa (PsA) is commonly found in soil and water so is impossible to avoid completely. Parents/carers of children with cystic fibrosis (CF) are concerned about them acquiring PsA from the environment, and different families view risk differently. Our ethos is to enable children with CF to take part as much as possible in educational and fun home activities, in order to maintain their quality of life (and their family's), and not have them feel different from other children. This review presents advice for families as to what they must definitely avoid, what they must take precautions with but can allow, and what they must not avoid. It is mostly evidence-based, but where evidence is lacking it a consensus view from the Paediatric CF Unit at the Royal Brompton Hospital.

Water as a Source of Antimicrobial Resistance and Healthcare-Associated Infections

Healthcare-associated infections (HAIs) are one of the most common patient complications, affecting 7% of patients in developed countries each year. The rise of antimicrobial resistant (AMR) bacteria has been identified as one of the biggest global health challenges, resulting in an estimated 23,000 deaths in the US annually. Environmental reservoirs for AMR bacteria such as bed rails, light switches and doorknobs have been identified in the past and addressed with infection prevention guidelines. However, water and water-related devices are often overlooked as potential sources of HAI outbreaks. This systematic review examines the role of water and water-related devices in the transmission of AMR bacteria responsible for HAIs, discussing common waterborne devices, pathogens, and surveillance strategies. AMR strains of previously described waterborne pathogens including Pseudomonas aeruginosa, Mycobacterium spp., and Legionella spp. were commonly isolated. However, methicillin-resistant Staphylococcus aureus and carbapenem-resistant Enterobacteriaceae that are not typically associated with water were also isolated. Biofilms were identified as a hot spot for the dissemination of genes responsible for survival functions. A limitation identified was a lack of consistency between environmental screening scope, isolation methodology, and antimicrobial resistance characterization. Broad universal environmental surveillance guidelines must be developed and adopted to monitor AMR pathogens, allowing prediction of future threats before waterborne infection outbreaks occur.

Multicenter Outbreak of Gram-Negative Bloodstream Infections in Hemodialysis Patients

RATIONALE & OBJECTIVE

Contaminated water and other fluids are increasingly recognized to be associated with health care-associated infections. We investigated an outbreak of Gram-negative bloodstream infections at 3 outpatient hemodialysis facilities.

STUDY DESIGN

Matched case-control investigations.

SETTING & PARTICIPANTS

Patients who received hemodialysis at Facility A, B, or C from July 2015 to November 2016.

EXPOSURES

Infection control practices, sources of water, dialyzer reuse, injection medication handling, dialysis circuit priming, water and dialysate test findings, environmental reservoirs such as wall boxes, vascular access care practices, pulsed-field gel electrophoresis, and whole-genome sequencing of bacterial isolates.

OUTCOMES

Cases were defined by a positive blood culture for any Gram-negative bacteria drawn July 1, 2015 to November 30, 2016 from a patient who had received hemodialysis at Facility A, B, or C.

ANALYTICAL APPROACH

Exposures in cases and controls were compared using matched univariate conditional logistic regression.

RESULTS

58 cases of Gram-negative bloodstream infection occurred; 48 (83%) required hospitalization. The predominant organisms were Serratia marcescens (n=21) and Pseudomonas aeruginosa (n=12). Compared with controls, cases had higher odds of using a central venous catheter for dialysis (matched odds ratio, 54.32; lower bound of the 95% CI, 12.19). Facility staff reported pooling and regurgitation of waste fluid at recessed wall boxes that house connections for dialysate components and the effluent drain within dialysis treatment stations. Environmental samples yielded S marcescens and P aeruginosa from wall boxes. S marcescens isolated from wall boxes and case-patients from the same facilities were closely related by pulsed-field gel electrophoresis and whole-genome sequencing. We identified opportunities for health care workers' hands to contaminate central venous catheters with contaminated fluid from the wall boxes.

LIMITATIONS

Limited patient isolates for testing, on-site investigation occurred after peak of infections.

CONCLUSIONS

This large outbreak was linked to wall boxes, a previously undescribed source of contaminated fluid and biofilms in the immediate patient care environment.

Infection Control and the Need for Family-/Child-Centered Care

Patient- and family-centered care (FCC) has become central to the delivery of medical care over the last 20 years and has been shown to improve patient outcomes. Infection control practices have the potential to greatly influence family centeredness and care providers, and hospital personnel must consider the potential impacts of isolation and the use of personal protective equipment (PPE). Approaching infection control with the perspective of FCC requires balancing patient safety and overall patient well-being. In this chapter, authors consider infection control and the benefits of FCC, family and sibling visitation, the use of playrooms, animals in healthcare settings including animal-assisted interventions, the potential adverse effects of infection control practices, and strategies to mitigate these impacts.

The Role of Patient Care Items as a Fomite in Healthcare-Associated Outbreaks and Infection Prevention

Patient-care items can serve as a source or reservoir for healthcare-associated pathogens in hospitals. We reviewed healthcare- associated outbreaks from medical equipment and provide infection prevention recommendations. Multiple healthcare-associated outbreaks via a contaminated patient-care item were identified, including infections with multidrug-resistant organisms. The type of patient care items implicated as a fomite causing healthcare-associated infections (HAIs) has changed over time. Patient populations at risk were most commonly critically ill patients in adult and neonatal intensive care units. Most fomite related healthcare-associated outbreaks were due to inappropriate disinfection practices. Repeated healthcare-associated outbreaks via medical equipment highlight the need for infectious disease professionals to understand that fomites/medical devices may be a source of HAIs. The introduction of new and more complex medical devices will likely increase the risk that such devices serve as a source of HAIs. Assuring appropriate cleaning and disinfection or sterilization of medical equipment is necessary to prevent future fomite-associated outbreaks.

Ugly ducklings-the dark side of plastic materials in contact with potable water

Bath toys pose an interesting link between flexible plastic materials, potable water, external microbial and nutrient contamination, and potentially vulnerable end-users. Here, we characterized biofilm communities inside 19 bath toys used under real conditions. In addition, some determinants for biofilm formation were assessed, using six identical bath toys under controlled conditions with either clean water prior to bathing or dirty water after bathing. All examined bath toys revealed notable biofilms on their inner surface, with average total bacterial numbers of 5.5 × 10⁶ cells/cm² (clean water controls), 9.5 × 10⁶ cells/cm² (real bath toys), and 7.3 × 10⁷ cells/cm² (dirty water controls). Bacterial community compositions were diverse, showing many rare taxa in real bath toys and rather distinct communities in control bath toys, with a noticeable difference between clean and dirty water control biofilms. Fungi were identified in 58% of all real bath toys and in all dirty water control toys. Based on the comparison of clean water and dirty water control bath toys, we argue that bath toy biofilms are influenced by (1) the organic carbon leaching from the flexible plastic material, (2) the chemical and biological tap water quality, (3) additional nutrients from care products and human body fluids in the bath water, as well as, (4) additional bacteria from dirt and/or the end-users’ microbiome. The present study gives a detailed characterization of bath toy biofilms and a better understanding of determinants for biofilm formation and development in systems comprising plastic materials in contact with potable water.

While bathing typically means good hygiene, bath toys can serve as incubators for microbial growth. Microbes colonize nearly every natural and human-made surface, sometimes living within complex communities called biofilms. A team led by Frederik Hammes at the Swiss Federal Institute of Aquatic Science and Technology found that tap water bacteria and fungi readily formed biofilms inside bath toys, suggesting that bathing provides food for microbes. These nutrients may come from bath toys’ polymeric material, from care products like soap and from human secretions like sweat. While 16S rRNA sequence analysis found that some of the microbes were related to disease-causing strains, future work is needed to assess the disease risk from these bath toy-associated biofilms. This work sheds light on how microbes are spread by our routine activities and that we are bathed in microbes, literally.

Infection Prevention and Control in Pediatric Ambulatory Settings

Since the American Academy of Pediatrics published its statement titled "Infection Prevention and Control in Pediatric Ambulatory Settings" in 2007, there have been significant changes that prompted this updated statement. Infection prevention and control is an integral part of pediatric practice in ambulatory medical settings as well as in hospitals. Infection prevention and control practices should begin at the time the ambulatory visit is scheduled. All health care personnel should be educated regarding the routes of transmission and techniques used to prevent the transmission of infectious agents. Policies for infection prevention and control should be written, readily available, updated every 2 years, and enforced. Many of the recommendations for infection control and prevention from the Centers for Disease Control and Prevention for hospitalized patients are also applicable in the ambulatory setting. These recommendations include requirements for pediatricians to take precautions to identify and protect employees likely to be exposed to blood or other potentially infectious materials while on the job. In addition to emphasizing the key principles of infection prevention and control in this policy, we update those that are relevant to the ambulatory care patient. These guidelines emphasize the role of hand hygiene and the implementation of diagnosis- and syndrome-specific isolation precautions, with the exemption of the use of gloves for routine diaper changes and wiping a well child's nose or tears for most patient encounters. Additional topics include respiratory hygiene and cough etiquette strategies for patients with a respiratory tract infection, including those relevant for special populations like patients with cystic fibrosis or those in short-term residential facilities; separation of infected, contagious children from uninfected children when feasible; safe handling and disposal of needles and other sharp medical devices; appropriate use of personal protective equipment, such as gloves, gowns, masks, and eye protection; and appropriate use of sterilization, disinfection, and antisepsis. Lastly, in this policy, we emphasize the importance of public health interventions, including vaccination for patients and health care personnel, and outline the responsibilities of the health care provider related to prompt public health notification for specific reportable diseases and communication with colleagues who may be providing subsequent care of an infected patient to optimize the use of isolation precautions and limit the spread of contagions.

Multilocus sequence typing analysis of Pseudomonas aeruginosa isolated from pet Chinese stripe-necked turtles (Ocadia sinensis)

Our research sought to characterize the phylogeny of Pseudomonas aeruginosa isolated from pet Chinese stripe-necked turtles (Ocadia sinensis) to better understand its evolutionary relation to other isolates and increase understanding of a potential zoonotic pathogen transmitted through direct contact with pet turtles. Thirty-one Pseudomonas aeruginosa isolates were obtained from both immature and adult turtles sold in pet shops in Korea. To characterize the phylogenic position of Chinese stripe-necked turtle-borne P. aeruginosa relative to other strains, multilocus sequence typing (MLST) analysis was performed due to the accessibility and breadth of MLST databases. Seven housekeeping genes (acsA, aroE, guaA, mutL, nuoD, ppsA, and trpE) were sequenced and the results were compared with data from the MLST database. The genes were further used for phylogenetic analysis of P. aeruginosa using concatenated gene fragments. Both rooted and unrooted phylogenetic trees were generated. Eleven distinct sequence types were present within the isolates among which seven were new. Expanding an unrooted phylogenetic tree to include P. aeruginosa MLST sequences isolated from various other geographic locations and sources revealed a divergent cluster containing the majority of isolates obtained from turtles. This suggests that P. aeruginosa strains particularly well-adapted for inhabiting turtles occupy a distinct phylogenetic position.

Survival of an Enveloped Virus on Toys

Children's toys may carry respiratory viruses. Inactivation of a lipid-enveloped bacteriophage, Φ6, was measured on a nonporous toy at indoor temperature and relative humidity (RH). Inactivation was approximately 2log10 after 24 hours at 60% RH and 6.8log10 at 10 hours at 40% RH. Enveloped viruses can potentially survive on toys long enough to result in exposures.

Recommendations from a European Roundtable Meeting on Best Practice Healthy Infant Skin Care

BACKGROUND

European roundtable meeting recommendations on bathing and cleansing of infants were published in 2009; a second meeting was held to update and expand these recommendations in light of new evidence and the continued need to address uncertainty surrounding this aspect of routine care.

METHODS

The previous roundtable recommendations concerning infant cleansing, bathing, and use of liquid cleansers were critically reviewed and updated and the quality of evidence was evaluated using the Grading of Recommendation Assessment, Development and Evaluation system. New recommendations were developed to provide guidance on diaper care and the use of emollients. A series of recommendations was formulated to characterize the attributes of ideal liquid cleansers, wipes, and emollients.

RESULTS

Newborn bathing can be performed without harming the infant, provided basic safety procedures are followed. Water alone or appropriately designed liquid cleansers can be used during bathing without impairing the skin maturation process. The diaper area should be kept clean and dry; from birth, the diaper area may be gently cleansed with cotton balls/squares and water or by using appropriately designed wipes. Appropriately formulated emollients can be used to maintain and enhance skin barrier function. Appropriately formulated baby oils can be applied for physiologic (transitory) skin dryness and in small quantities to the bath. Baby products that are left on should be formulated to buffer and maintain babies' skin surface at approximately pH 5.5, and the formulations and their constituent ingredients should have undergone an extensive program of safety testing. Formulations should be effectively preserved; products containing harsh surfactants, such as sodium lauryl sulfate, should be avoided.

CONCLUSION

Health care professionals can use these recommendations as the basis of their advice to parents.

Aetiology, source and prevention of waterborne healthcare-associated infections: a review

The purpose of this review is to discuss the scientific literature on waterborne healthcare-associated infections (HCAIs) published from 1990 to 2012. The review focuses on aquatic bacteria and describes both outbreaks and single cases in relation to patient characteristics, the settings and contaminated sources. An overview of diagnostic methods and environmental investigations is summarized in order to provide guidance for future case investigations. Lastly, on the basis of the prevention and control measures adopted, information and recommendations are given. A total of 125 reports were included, 41 describing hospitalized children. All cases were sustained by opportunistic pathogens, mainly Legionellaceae, Pseudomonadaceae and Burkholderiaceae. Hot-water distribution systems were the primary source of legionnaires’ disease, bottled water was mainly colonized by Pseudomonaceae, and Burkholderiaceae were the leading cause of distilled and sterile water contamination. The intensive care unit was the most frequently involved setting, but patient characteristics were the main risk factor, independent of the ward. As it is difficult to avoid water contamination by microbes and disinfection treatments may be insufficient to control the risk of infection, a proactive preventive plan should be put in place. Nursing staff should pay special attention to children and immunosuppressed patients in terms of tap-water exposure and also their personal hygiene, and should regularly use sterile water for rinsing/cleaning devices.

An outbreak of extremely drug-resistant Pseudomonas aeruginosa in a tertiary care pediatric hospital in Italy

Background

Extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) isolates are susceptible to only one or two classes of antibiotics. In 2011–2012, we investigated an outbreak of XDR-PA affecting children with onco-hematological diseases.

Methods

Outbreak investigation included ascertainment of cases, tracing of intestinal carriers and environmental surveillance. Contact precautions were adopted for patients with infection or colonization. Isolates were tested for antimicrobial susceptibility; phenotypic confirmation of carbapenemase production was performed, and carbapenemase genes were tested by multiplex polymerase-chain-reaction (PCR). Genotypes were determined by pulsed-field gel electrophoresis (PFGE).

Results

XDR-PA was isolated from 27 patients; 12 had bacteremia, 6 other infections and 9 were colonized. Severe neutropenia was significantly associated with bacteremia. Bloodstream-infection mortality rate was 67%. All isolates were resistant to carbapenems, cephalosporins and penicillins + β-lactamase inhibitors. Isolates were susceptible only to colistin in 22 patients, to colistin and amikacin in 4, and to ciprofloxacin and colistin in 1. PFGE results identified 6 subtypes of a single genotype, associated with clusters of cases, and 4 sporadic genotypes. Two sporadic isolates were metallo-β-lactamase producers, negative to PCR. All other isolates were metallo-β-lactamase producers due to the presence of a VIM carbapenemase. Incidence of XDR-PA infections decreased from 0.72 cases/1,000 inpatient-days in March 2011-March 2012, to 0.34/1,000 in April-December 2012, after implementation of active finding of intestinal carriers on all onco-hematological inpatients.

Conclusions

Control measures targeting intestinal carriers are crucial in limiting in-hospital transmission of XDR-PA polyclonal strains, protecting more vulnerable patients, such as severely neutropenic children, from developing clinical infections.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-494) contains supplementary material, which is available to authorized users.

An outbreak of extremely drug-resistant Pseudomonas aeruginosa in a tertiary care pediatric hospital in Italy

BACKGROUND

Extensively drug-resistant Pseudomonas aeruginosa (XDR-PA) isolates are susceptible to only one or two classes of antibiotics. In 2011-2012, we investigated an outbreak of XDR-PA affecting children with onco-hematological diseases.

METHODS

Outbreak investigation included ascertainment of cases, tracing of intestinal carriers and environmental surveillance. Contact precautions were adopted for patients with infection or colonization. Isolates were tested for antimicrobial susceptibility; phenotypic confirmation of carbapenemase production was performed, and carbapenemase genes were tested by multiplex polymerase-chain-reaction (PCR). Genotypes were determined by pulsed-field gel electrophoresis (PFGE).

RESULTS

XDR-PA was isolated from 27 patients; 12 had bacteremia, 6 other infections and 9 were colonized. Severe neutropenia was significantly associated with bacteremia. Bloodstream-infection mortality rate was 67%. All isolates were resistant to carbapenems, cephalosporins and penicillins + β-lactamase inhibitors. Isolates were susceptible only to colistin in 22 patients, to colistin and amikacin in 4, and to ciprofloxacin and colistin in 1. PFGE results identified 6 subtypes of a single genotype, associated with clusters of cases, and 4 sporadic genotypes. Two sporadic isolates were metallo-β-lactamase producers, negative to PCR. All other isolates were metallo-β-lactamase producers due to the presence of a VIM carbapenemase. Incidence of XDR-PA infections decreased from 0.72 cases/1,000 inpatient-days in March 2011-March 2012, to 0.34/1,000 in April-December 2012, after implementation of active finding of intestinal carriers on all onco-hematological inpatients.

CONCLUSIONS

Control measures targeting intestinal carriers are crucial in limiting in-hospital transmission of XDR-PA polyclonal strains, protecting more vulnerable patients, such as severely neutropenic children, from developing clinical infections.

The role of water in healthcare-associated infections

PURPOSE OF REVIEW

The aim is to discuss the epidemiology of infections that arise from contaminated water in healthcare settings, including Legionnaires' disease, other Gram-negative pathogens, nontuberculous mycobacteria, and fungi.

RECENT FINDINGS

Legionella can colonize a hospital water system and infect patients despite use of preventive disinfectants. Evidence-based measures are available for secondary prevention. Vulnerable patients can develop healthcare-associated infections with waterborne organisms that are transmitted by colonization of plumbing systems, including sinks and their fixtures. Room humidifiers and decorative fountains have been implicated in serious outbreaks, and pose unwarranted risks in healthcare settings.

SUMMARY

Design of hospital plumbing must be purposeful and thoughtful to avoid the features that foster growth and dissemination of Legionella and other pathogens. Exposure of patients who have central venous catheters and other invasive devices to tap water poses a risk for infection with waterborne pathogens. Healthcare facilities must conduct aggressive clinical surveillance for Legionnaires' disease and other waterborne infections in order to detect and remediate an outbreak promptly. Hand hygiene is the most important measure to prevent transmission of other Gram-negative waterborne pathogens in the healthcare setting.

Infecciones nosocomiales en pediatría

Numerosas son las particularidades de la población pediátrica que deben intervenir, en nuestra opinión, en el control de las infecciones nosocomiales. Los riesgos y los agentes patógenos responsables son diferentes en función del tipo de población (prematuros, recién nacidos, otros). Además, esta población, que comparte los mismos factores de riesgo de infecciones nosocomiales que la población adulta (hospitalización en reanimación, cateterismos, etc.), se distingue no sólo por la inmadurez del sistema inmunitario de los recién nacidos, sino también por la multiplicidad de los participantes, desde los sanitarios hasta los padres, pasando por los educadores y los acompañantes (visitantes de todo tipo, etc.) necesarios para el desarrollo conductual y emocional del niño. Además, es importante subrayar el aumento del riesgo ligado a los contactos frecuentes, cercanos e íntimos que están parcial e incluso totalmente ausentes en el ámbito hospitalario «adulto». Así como existen riesgos de transmisión cruzada a través del principal vector constituido por los sanitarios, el control del riesgo no puede excluir a los educadores, a los acompañantes, a los padres y a los mismos niños. Si el riesgo en la esfera adulta está limitado a las actividades médicas, en la esfera pediátrica se comparte con las demás actividades (juegos, enseñanza, etc.), que con frecuencia son comunes. Todos estos riesgos son todavía mayores debido a la prevalencia de los agentes patógenos como los virus (respiratorios y digestivos), la frecuencia de las antibioticoterapias y la dificultad de los diagnósticos etiológicos, dada la inespecificidad de los signos clínicos y la actitud diagnóstica poco o nada invasiva. De esta manera, el control del riesgo infeccioso nosocomial se resume en los siguientes elementos: un reservorio importante y difícilmente identificable, numerosos vectores potenciales, una población expuesta de manera variable al riesgo, todo ello sin olvidar las necesidades emocionales de los niños y los comportamientos «culturales».

Nontuberculous mycobacteria, fungi, and opportunistic pathogens in unchlorinated drinking water in The Netherlands

The multiplication of opportunistic pathogens in drinking water supplies might pose a threat to public health. In this study, distributed unchlorinated drinking water from eight treatment plants in the Netherlands was sampled and analyzed for fungi, nontuberculous mycobacteria (NTM), and several opportunistic pathogens by using selective quantitative PCR methods. Fungi and NTM were detected in all drinking water samples, whereas Legionella pneumophila, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Aspergillus fumigatus were sporadically observed. Mycobacterium avium complex and Acanthamoeba spp. were not detected. Season had no influence on the occurrence of these organisms, except for NTM and S. maltophilia, which were present in higher numbers in the summer. Opportunistic pathogens were more often observed in premise plumbing water samples than in samples from the distribution system. The lowest number of these organisms was observed in the finished water at the plant. Thus, fungi, NTM, and some of the studied opportunistic pathogens can multiply in the distribution and premise plumbing systems. Assimilable organic carbon (AOC) and/or total organic carbon (TOC) had no clear effects on fungal and NTM numbers or on P. aeruginosa- and S. maltophilia-positive samples. However, L. pneumophila was detected more often in water with AOC concentrations above 10 μg C liter(-1) than in water with AOC levels below 5 μg C liter(-1). Finally, samples that contained L. pneumophila, P. aeruginosa, or S. maltophilia were more frequently positive for a second opportunistic pathogen, which shows that certain drinking water types and/or sampling locations promote the growth of multiple opportunistic pathogens.

Preventing transmission of infectious agents in the pediatric in-patients hematology-oncology setting: what is the role for non-pharmacological prophylaxis?

The most intensive chemotherapy regimens were used in the past for leukemia patients who were the main focus of trials on infections; today there are increasing numbers of children with solid cancer and considerable risk of infection who do receive intensive standard-dose chemotherapy. Despite a continuous will to protect the immune-compromised child from infections, evidence-based indications for intervention by non-pharmacological tools is still lacking in the pediatric hematology-oncology literature. Guidelines on standard precautions as well as precautions to avoid transmission of specific infectious agents are available. As a result of a consensus discussion, the Italian Association for Pediatric Hematology-Oncology (AIEOP) Cooperative Group centers agree that for children treated with chemotherapy both of these approaches should be implemented and vigorously enforced, while additional policies, including strict environmental isolation, should be restricted to patients with selected clinical conditions or complications. We present here a study by the working group on infectious diseases of AIEOP.

[Audit "Toys and incubators in neonatology"]

Owing to an increase in nosocomial septicaemias in the Neonatalogy department, we've judged it necessary to consider the role of items not linked to the nursing procedures, and nevertheless present in the incubators, as well as the hygiene techniques applied to them. In November 2007, we've made a longitudinal prospective study consisting in an observation audit during 3 successive days, observing every single incubator with a newborn baby. In each incubator, we've checked whether there were or not items that weren't required by the nursing activities, along with their characteristics and the hygiene procedures applied to them. We've inquired as well whether the parents and the nursing staff knew and applied the required hygiene procedures. In 13 among the 17 incubators under survey, at least one item not strictly required by the nursing procedures could be found. The number of toys in each incubator varied from seven to one. Among the 33 toys surveyed, 24 (73%) of them showed a score of maximum fluffiness (4 out of 4), and only 10 wore labels giving cleansing advice from the manufacturers. Without any record about the cleaning/disinfecting of the toys brought in hospital, we have observed that the parents were given varied advice about how to clean the toys at home before putting them in the incubators (only four parents had washed the toys in their washing machines at more than 30 degrees C). From the six samples under scrutiny, all the culture results were tested positive. In particular two of the soft toys sampled were found infected by a Pseudomonas oryzihabitans. These particular toys belonged to a baby who had been diagnosed with a septicaemia characterized by hemocultures positive to a P. oryzihabitans of a different strain. Our audit has been an efficient reminder that any item put in an incubator is a potential vector and reservoir of pathogen organisms. After a general feedback towards the department staff, the medical staff then prescribed to permanently ban all the items not strictly required by the nursing activities from all the incubators of the department.

Risk assessment of Pseudomonas aeruginosa in water

P. aeruginosa is part of a large group of free-living bacteria that are ubiquitous in the environment. This organism is often found in natural waters such as lakes and rivers in concentrations of 10/100 mL to >1,000/100 mL. However, it is not often found in drinking water. Usually it is found in 2% of samples, or less, and at concentrations up to 2,300 mL(-1) (Allen and Geldreich 1975) or more often at 3-4 CFU/mL. Its occurrence in drinking water is probably related more to its ability to colonize biofilms in plumbing fixtures (i.e., faucets, showerheads, etc.) than its presence in the distribution system or treated drinking water. P. aeruginosa can survive in deionized or distilled water (van der Jooij et al. 1982; Warburton et al. 1994). Hence, it may be found in low nutrient or oligotrophic environments, as well as in high nutrient environments such as in sewage and in the human body. P. aeruginosa can cause a wide range of infections, and is a leading cause of illness in immunocompromised individuals. In particular, it can be a serious pathogen in hospitals (Dembry et al. 1998). It can cause endocarditis, osteomyelitis, pneumonia, urinary tract infections, gastrointestinal infections, and meningitis, and is a leading cause of septicemia. P. aeruginosa is also a major cause of folliculitis and ear infections acquired by exposure to recreational waters containing the bacterium. In addition, it has been recognized as a serious cause of keratitis, especially in patients wearing contact lenses. P. aeruginosa is also a major pathogen in burn and cystic fibrosis (CF) patients and causes a high mortality rate in both populations (MOlina et al. 1991; Pollack 1995). P. aeruginosa is frequently found in whirlpools and hot tubs, sometimes in 94-100% of those tested at concenrations of <1 to 2,400 CFU/mL. The high concentrations found probably result from the relatively high temperatures of whirlpools, which favor the growth of P. aeruginosa, and the aeration which also enhances its growth. The organism is usually found in whirlpools when the chlorine concentrations are low, but it has been isolated even in the presence of 3.00 ppm residual free chlorine (Price and Ahearn 1988). Many outbreaks of folliculitis and ear infections have been reportedly associated with the use of whirlpools and hot tubs that contain P. aeruginosa (Ratnam et al. 1986). Outbreaks have also been reported from exposure to P. aeruginosa in swimming pools and water slides. Although P. aeruginosa has a reputation for being resistant to disinfection, most studies show that it does not exhibit any marked resistance to the disinfectants used to treat drinking water such as chlorine, chloramines, ozone, or iodine. One author, however, did find it to be slightly more resistant to UV disinfection than most other bacteria (Wolfe 1990). Although much has been written about biofilms in the drinking water industry, very little has been reported regarding the role of P. aeruginosa in biofilms. Tap water appears to be a significant route of transmission in hospitals, from colonization of plumbing fixtures. It is still not clear if the colonization results from the water in the distribution system, or personnel use within the hospital. Infections and colonization can be significantly reduced by placement of filters on the water taps. The oral dose of P. aeruginosa required to establish colonization in a healthy subject is high (George et al. 1989a). During dose-response studies, even when subjects (mice or humans) were colonized via ingestion, there was no evidence of disease. P. aeruginosa administered by the aerosol route at levels of 10(7) cells did cause disease symptoms in mice, and was lethal in aerosolized doses of 10(9) cells. Aerosol dose-response studies have not been undertaken with human subjects. Human health risks associated with exposure to P. aeruginosa via drinking water ingestion were estimated using a four-step risk assessment approach. The risk of colonization from ingesting P. aeruginosa in drinking water is low. The risk is slightly higher if the subject is taking an antibiotic resisted by P. aeruginosa. The fact that individuals on ampicillin are more susceptible to Pseudomonas gastrointestinal infection probably results from suppression of normal intestinal flora, which would allow Pseudomonas to colonize. The process of estimating risk was significantly constrained because of the absence of specific (quantitative) occurrence data for Pseudomonas. Sensitivity analysis shows that the greatest source of variability/uncertainty in the risk assessment is from the density distribution in the exposure rather than the dose-response or water consumption distributions. In summary, two routes appear to carry the greatest health risks from contacting water contaminated with P. aeruginosa (1) skin exposure in hot tubs and (2) lung exposure from inhaling aerosols.

Infection prevention and control in pediatric ambulatory settings

Since the American Academy of Pediatrics published a statement titled "Infection Control in Physicians' Offices" (Pediatrics. 2000;105[6]:1361-1369), there have been significant changes that prompted this updated statement. Infection prevention and control is an integral part of pediatric practice in ambulatory medical settings as well as in hospitals. Infection prevention and control practices should begin at the time the ambulatory visit is scheduled. All health care personnel should be educated regarding the routes of transmission and techniques used to prevent transmission of infectious agents. Policies for infection prevention and control should be written, readily available, updated annually, and enforced. The standard precautions for hospitalized patients from the Centers for Disease Control and Prevention, with a modification from the American Academy of Pediatrics exempting the use of gloves for routine diaper changes and wiping a well child's nose or tears, are appropriate for most patient encounters. As employers, pediatricians are required by the Occupational Safety and Health Administration to take precautions to identify and protect employees who are likely to be exposed to blood or other potentially infectious materials while on the job. Key principles of standard precautions include hand hygiene (ie, use of alcohol-based hand rub or hand-washing with soap [plain or antimicrobial] and water) before and after every patient contact; implementation of respiratory hygiene and cough-etiquette strategies for patients with suspected influenza or infection with another respiratory tract pathogen to the extent feasible; separation of infected, contagious children from uninfected children when feasible; safe handling and disposal of needles and other sharp medical devices and evaluation and implementation of needle-safety devices; appropriate use of personal protective equipment such as gloves, gowns, masks, and eye protection; and appropriate sterilization, disinfection, and antisepsis.

Microbiological quality of carbonated drinking water produced with in-home carbonation systems

The microbiological quality of carbonated water produced with tap water in commercial in-home carbonation systems was determined, the results being discussed in the context of the microbiological quality of the tap water used, the properties of the drink makers, and the procedures of preparation and washing of various parts of the appliance. The last-mentioned data were received from each participant of the study by questionnaire. Escherichia coli, coliforms, fecal streptococci and spore-forming sulphite-reducing anaerobes were used as indicators for the hygienic quality of the water. Tap-water samples were collected according to the usual procedure when filling the carbonating bottle, i.e., without previous flushing and disinfection of the faucet. In 12% of tap-water samples, coliforms could be detected. On the other hand, in 20 of 52 carbonated waters (39%), coliforms as indicators of water pollution were found. By means of fecal streptococci and Pseudomonas aeruginosa, it was possible to establish additional contamination not involving E. coli or coliforms alone. Analysis revealed that, in addition to contaminated tap water, a bacterial biofilm on the inner surface of the re-usable bottles had a predominant influence on the microbiological quality of the carbonated water.

[Epidemiology of nosocomial infections due to Pseudomonas aeruginosa, Burkholderia cepacia and Stenotrophomonas maltophilia]

Non-fermentative Gram negative rods are opportunistic pathogens responsible for nosocomial infections. Using phenotypic markers (serotypes for Pseudomonas aeruginosa and antibiotic susceptibility) allows a preliminary screening of epidemiologically-related strains. However, genotypic markers are necessary to better characterize nosocomial strains for the investigation of outbreaks or cross-transmissions in the hospital setting. Infections due to P. aeruginosa, Burkholderia. cepacia or Stenotrophomonas. maltophilia are usually hospital-acquired and responsible for a high mortality rate as illustrated by the lethality of nosocomial pneumonia due to P. aeruginosa. The severity of these infections is due to the virulence factors of the bacteria and to their occurrence in debilitated patients in whom invasives devices are used. The hospital environment can act as a reservoir with a rate of exogeneous transmission of these bacteria as high as 50% in some studies. To better prevent nosocomial infections related to Gram negative non fermentative rods, the control of the aqueous hospital environment, the strict application of hand disinfection and the investigation of potential cross-transmission in the hospital setting are needed.

Hospital water point-of-use filtration: a complementary strategy to reduce the risk of nosocomial infection

Cholera, hepatitis and typhoid are well-recognized water-borne illnesses that take the lives of many every year in areas of uncontrollable flood, but far less attention is afforded to the allegedly safe potable water in affluent nations and the presumed healthful quality of water in communities and hospitals. Recent literature, however, points to increasing awareness of serious clinical sequelae particularly experienced by immunocompromised patients at high risk for disease and death from exposure to water-borne microbes in hospitals. This review reflects the literature indicting hospital water as an important source for nosocomial infections, examines patient populations at greatest risk, uncovers examples of failures in remedial water treatment methods and the reasons for them, and introduces point-of-use water filtration as a practical alternative or complementary component of an infection control strategy that may reduce the risk of nosocomial infections.

Host defense peptides in burns

Overuse of antibiotics and failure to apply basic infection control policies and procedures have contributed to the increasing multi-drug resistance of many nosocomial pathogens. The alarming increase of multi-drug-resistant bacteria (e.g. Pseudomonas aeruginosa, methicilin-resistant Staphylococci, vancomycin-resistant Enterococci) causes infected wounds associated with high mortality and morbidity in burned patients and focuses attention on the need for better treatment and prevention of wound infections. The review points out and discusses some emerging alternatives to antibiotics used in clinical practice, with special emphasis on the role of the innate immune response and potential application of human host defense peptides in thermal injury.

Toys in a pediatric hospital: are they a bacterial source?

BACKGROUND

In children's hospitals, children are commonly provided with toys. Measures to guarantee the safety of these toys are usually not taken. This study was conducted to determine whether toys were contaminated with potentially pathogenic bacteria when they arrived in the hospital, and whether they were contaminated in the hospital.

METHODS

The study was conducted during a 3-month period. Children who were hospitalized for at least 3 days were chosen as study subjects. Once these children were identified, cultures from their toys were obtained within the first 48 hours of admission. After this first culture, toys were cleaned with 4% chlorhexidine and water and were immediately re-cultured. Following cultures were collected on days 5 to 7, 10 to 15, and every week thereafter until the owner-patient was discharged. Specimens were collected in a standardized manner with moistened swabs and placed in transport media. They were later inoculated onto trypticase soy agar with 5% sheep blood and brain heart infusion agar, incubated at 37 degrees C for 48 hours and examined for colony growth at 24 to 48 hours.

RESULTS

Seventy children's toys were included in this study. Patients' median age was 26 months (range: 1 day to 9 years). Respiratory infections (43%) and diarrhea (26%) were the most common causes of hospitalization. Fifty-three (76%) toys were made of plastic, 8 (11%) metallic, and 9 (13%) other materials. Twenty-nine (41%) were brought from home, 38 (55%) were purchased from roving vendors, and 3 (4%) were purchased from toy stores. All first cultures were positive for at least 1 pathogenic microorganism: 55 (78%) coagulase-negative Staphylococcus (CNS); 26 (37%) Bacillus spp; 13 (18%) Staphylococcus aureus; 8 (11%) alpha-hemolytic Streptococcus; 5 (9%), Pseudomonas spp; 2 (3%) Stenotrophomonas maltophilia, and 6 (11%) other gram-negative organisms. After toys were cleaned, subsequent cultures showed significant decreases in bacterial growth rates (P <.05). Because some patients were discharged, additional cultures were obtained for only 31 toys.

CONCLUSIONS

Toys entering a hospital can be contaminated with potentially dangerous bacteria and may provide unnecessary risks for nosocomial infection. Effective measures must be implemented to prevent the spread of infections via toys.

Evidence-based practice: examining the risk of toys in the microenvironment of infants in the neonatal intensive care unit

Toys placed in the bed or microenvironment of infants in the neonatal intensive care unit (NICU) demonstrate high rates of colonization (92%). As with other fomites, toys may be one potential source of nosocomial infection (NI). This project critically evaluated the practice of placing toys in the microenvironment of critically ill infants by using the Iowa Model of Evidence-Based Practice to Promote Quality Care. With the model as a guide for decision making, the existing evidence was explored using a systematic review of the literature, case studies, scientific principles, theory, and expert opinion. A comprehensive review of the literature did not clearly identify a causal relationship between toys in the NICU microenvironment and NI. Levels of evidence suggesting an association between toys and NI were determined to be moderately strong and consistent. A plausible relationship between the practice of placing toys in the beds of NICU patients and risk for infection was found. These findings prompted a pilot practice change, eliminating toys in the NICU, to test the potential impact of this intervention. Pre- and postintervention infection rates were compared. NI rates decreased from 4.6 to 1.99 per 1,000 patient days over a 6-month evaluation period. Although this decrease was not statistically significant, it was the lowest rate recorded in 5 years. Ongoing evaluation of NI rates is in progress. Individual NICUs must determine if the evidence warrants a practice change in their setting.

Contamination Control in Nursing With Filtration

Filters often are viewed as screens with openings smaller than the particles intended to be removed by a process technically known as direct interception. However, filter manufacturing embraces far more advanced technological approaches, with an evolution toward selective removal of cells or soluble constituents from complex physiologic solutions. An appreciation of filtration development makes it easy to understand how differently manufactured filters with the same claims may not perform identically. This article focuses on the filtration of intravenous solutions and point-of-use hospital water.

Surveillance of Pseudomonas aeruginosa-isolates in a neonatal intensive care unit over a one year-period

Outbreaks of gram-negative bacteria such as Pseudomonas aeruginosa in neonatal intensive care units (NICU) can be life-threatening to pre-term infants, which are highly susceptible to serious infections with bacteria. Forty-two ventilated neonates in the NICU of the University Children's Hospital of Tuebingen were found to be colonized (n = 40) or infected (n = 2) with P. aeruginosa within a sampling period of one year. To investigate the colonization patterns and identify potential outbreak sources, epidemiological investigations, environmental surveillance and typing by serotyping and pulsed-field gel electrophoresis of the recovered isolates were performed. The investigation demonstrated a genetically related cluster of P. aeruginosa isolates during the surveillance period in 39 neonates and a second cluster at the end of the period in two neonates. A third strain representing a genetically distinct group was found in only one patient. Environmental investigations demonstrated the presence of P. aeruginosa in the ventilation equipment of 22 patients: binasal prongs (n = 22), water reservoir (n = 9), and heater (n = 1). In one case, P. aeruginosa was found in breast milk. Other environmental investigations revealed no P. aeruginosa. Although no evidence for a unique source was found, a series of intervention steps were initiated by the NICU personnel, medical microbiologists and infection control experts. The intervention steps included reinforced training of health care staff and a change from chemical to thermal disinfection of binasal prongs. Implementation of these measurements successfully stopped the recurrent occurrence of P. aeruginosa colonization.

Pseudomonas aeruginosa infections in a neonatal intensive care unit

This report describes a cluster of nosocomial infections with Pseudomonas aeruginosa in a neonatal intensive care nursery. All 5 cases of P aeruginosa infection were clustered in September 1999. Aggressive infection control measures were instituted, including installation of a user-friendly handwashing soap and environmental cleaning. On the basis of the finding of persistent dirty equipment, a new full-time position was created that was dedicated to equipment cleaning. These measures were effective in eliminating the cluster. The nursery has remained free of P aeruginosa infection for more than 2 years, attesting to the success of our program.

Analysis of transmission pathways of Pseudomonas aeruginosa between patients and tap water outlets

OBJECTIVE

To study the association between infection and faucet contamination in a surgical intensive care unit (SICU).

DESIGN

Prospective cohort study.

SETTING

One SICU and 12 peripheral wards.

PATIENTS

From 45 patients colonized or infected with P. aeruginosa, 87 positive isolates were collected.

INTERVENTIONS

P. aeruginosa also was found in 150 of 259 (58%) tap water samples taken from patient rooms.

MEASUREMENTS AND MAIN RESULTS

Clonal relationships between patient and tap water isolates were established by random amplification of polymorphic DNA-polymerase chain reaction. A long-time contamination (144 wks) with a single specific genotype for each of the faucets in our SICU was observed. Additional genotypes found in tap water from these faucets were only isolated over short periods of time. P. aeruginosa was shown to reside in single faucets and did not originate from the supplying mains. In 15 of 45 patients (33%), P. aeruginosa genotypes were identical to those from the faucets in the patient rooms. In six other patients, the same genotype was found in faucets from neighboring rooms. Faucets served as the source of infection for patients in 35% of cases, and on the other hand a retrograde contamination of faucets by patients was observed in 15% of cases.

CONCLUSIONS

Tap water from faucets contaminated with P. aeruginosa plays an important role in the propagation of this pathogen among patients. A high number of transmissions were shown to occur both from faucet to patient and from patient to faucet. Our SICU served as an epicenter for the spread of P. aeruginosa to peripheral wards. It appears prudent to follow strict hygienic precautions such as wearing gloves and performing thorough alcoholic rub disinfection of hands after patient care and after hand washing at locations known to harbor.

Activity of novispirin G10 against Pseudomonas aeruginosa in vitro and in infected burns

The emergence of multidrug-resistant microbes has serious implications for managing infection and sepsis and has stimulated efforts to develop alternative treatments, such as antimicrobial peptides. The objective of this study was to test a designer peptide, novispirin G10, against multidrug-resistant microorganisms. By two-stage radial diffusion assays, its activity against such organisms compared favorably with that of standard antibiotics and other antimicrobial peptides. It killed bacteria very rapidly, was nonhemolytic, and was relatively noncytotoxic. The peptide induced an immediate, massive efflux of potassium from Pseudomonas aeruginosa, suggesting that it altered the permeability of its inner membrane. The presence of human serum reduced but did not eliminate its activity. We tested the in vivo activity of novispirin G10 in rats with an infected, partial-thickness burn that covered 20% of their total body surface area. The burned area was seeded with 10(6) CFU of a Silvadene-resistant P. aeruginosa strain, and 24 h later a single treatment with 0, 1, 3, or 6 mg of synthetic novispirin G10 (n = 16 at each concentration) per kg was given intradermally. Significant bacterial killing (P < 0.0001) was evident within 4 h in each peptide group compared to controls receiving vehicle. Antimicrobial peptides such as novispirin G10 may provide a useful alternative or adjunct to standard antibiotic agents in treating burns or other wound infections.

Molecular epidemiology of coagulase-negative staphylococcal bacteraemia in a newborn intensive care unit

We isolated 55 coagulase-negative staphylococci (CoNS) over two separate 12-month periods (26 in 1993 and 29 in 1996) from the blood of neonates in a neonatal intensive case unit (NICU) in Melbourne, Australia and compared them by pulse-field gel electrophoresis profile (PFGE), random amplification of polymorphic DNA (RAPD) and antibiogram. The most common species were Staphylococcus epidermidis, S. haemolyticus and S. warneri. The majority of such isolates were resistant to penicillin and to either or both of methicillin and gentamicin. During 1993, there was an increase in the number of CoNS bloodstream infections compared with previous years. S. epidermidis was the most common isolate, with 88% assessed as clinically relevant. Using the three typing systems, we identified one likely epidemic clone of S. epidermidis, the isolates of which were resistant to penicillin, gentamicin and erythromycin and possessed the mecA gene. There was complete correlation between the detection of mecA and the phenotypic expression of resistance when zone diameters in the disc diffusion assay were interpreted according to the latest NCCLS guidelines (1999). Profiles of the remaining 1993 isolates were generally heterogeneous, suggesting independent acquisition with some evidence of cross-infection. The predominant bloodstream isolates in 1996 were heterogeneous multi-resistant strains of S. epidermidis, S. haemolyticus and S. warneri, about half of which were assessed as clinically relevant. These data support the view that CoNS are significant nosocomial pathogens in NICU and that resistant clones may be transmitted between babies. Molecular epidemiological tools are helpful for understanding transmission patterns and sources of infection, and are useful for measuring outcomes of intervention strategies implemented to reduce nosocomial CoNS sepsis. PFGE was found to be more discriminatory than RAPD, but the latter provides results in a more timely manner.

Effectiveness of fosfomycin combined with other antimicrobial agents against multidrug-resistant Pseudomonas aeruginosa isolates using the efficacy time index assay

We investigated the effectiveness of fosfomycin combined with other antibiotics, such as piperacillin, cefepime, ceftazidime, imipenem, meropenem, aztreonam, gentamicin, or levofloxacin, against 30 Pseudomonas aeruginosa strains, including multidrug-resistant strains, isolated from clinical specimens, using the efficacy time index (ETI) assay. The assay refers to the result of pharmacokinetics obtained from adult men volunteers, and yields an ETI to evaluate the effect of a combination of antimicrobial agents. With the ETI, based on serum concentration 3 h after the administration of two antimicrobial agents, the effectiveness of antimicrobial combinations was evaluated as follows: poor, ETI < 0.5; fair, 0.5 < or = ETI < 1; good, 1 < or = ETI < 8; and excellent, ETI > or = 8. The combination of fosfomycin and cefepime (efficacy rate [excellent plus good], 76.7%) and fosfomycin/aztreonam (efficacy rate, 76.7%) appeared to be the most effective, followed by fosfomycin/meropenem (efficacy rate, 76.6%), fosfomycin/imipenem (efficacy rate, 73.3%), fosfomycin/ceftazidime (efficacy rate, 70%), fosfomycin/gentamicin (efficacy rate, 70%), fosfomycin/piperacillin (efficacy rate, 66.7%), and fosfomycin/levofloxacin (efficacy rate, 66.7%). Fosfomycin/cefepime, fosfomycin/aztreonam, and fosfomycin/meropenem may be clinically useful in selected patients, particularly for P. aeruginosa. The ETI assay provided information on the minimum inhibitory concentration (MIC) of many pairs of combined antimicrobial agents simultaneously. The ETI assay may be a useful technique with which to investigate the effect of combinations of antimicrobial agents against P. aeruginosa, including multidrug-resistant strains.

Multidrug-resistant Pseudomonas aeruginosa isolated from the urine of patients with urinary tract infection

We report the clinical courses of 3 patients with urinary obstruction who developed acute pyelonephritis caused by multidrug-resistant (MDR) Pseudomonas aeruginosa. Genome fingerprinting was performed to clarify the route of cross-infection, and an imipenem-resistance gene was detected by the polymerase chain reaction (PCR) method. The study included 17 patients at our institute who had urinary tract infections caused by P. aeruginosa between January and December 1997. MDR was defined as that when all the minimum inhibitory concentrations (MICs) were determined to show resistance according to the breakpoints recommended by the National Committee for Clinical Laboratory Standards (NCCLS) for P. aeruginosa. Pulse-field gel electrophoresis (PFGE) was carried out for genome fingerprinting. PCR was used to detect the metallo-beta-lactamase gene ( bla(IMP)). Three strains were revealed for MDR. The strains were isolated from the 3 patients with urinary tract obstruction who developed acute pyelonephritis. The treatment consisted of urinary drainage for the obstructed urinary tract and parenterally administered antimicrobials. Although none of the strains was susceptible to any antimicrobials, all patients had favorable outcomes. PFGE revealed that two strains had an identical genotype, implying cross-infection between the patients. The bla(IMP) gene was not detected in any of the three strains. In febrile patients with urinary tract infection caused by MDR P. aeruginosa, treatment for urinary obstruction is strongly recommended. Initial empirical chemotherapy with antimicrobials to which the organism is not susceptible is often inevitable. Because there was epidemiological evidence of cross-infection with MDR P. aeruginosa, countermeasures against nosocominal infection are warranted.