An outbreak of Pseudomonas aeruginosa infections associated with flexible bronchoscopes

How to Assess Risk of Disease Transmission to Patients When There Is a Failure to Follow Recommended Disinfection and Sterilization Guidelines

Background.

Disinfection and sterilization are critical components of infection control. Unfortunately, breaches of disinfection and sterilization guidelines are not uncommon.

Objective.

To describe a method for evaluating a potential breach of guidelines for high-level disinfection and sterilization of medical devices.

Methods.

The appropriate scientific literature was reviewed to determine the frequency of failures of compliance. A risk assessment model was constructed.

Results.

A 14-step protocol was constructed to aid infection control professionals in the evaluation of potential disinfection and sterilization failures. In addition, a model is presented for aiding in determining how patients should be notified of the potential adverse event. Sample statements and letters are provided for communicating with the public and individual patients.

Conclusion.

Use of a protocol can guide an institution in managing potential disinfection and sterilization failures.

Risk Factors forBurkholderia cepaciaComplex Bacteremia Among Intensive Care Unit Patients Without Cystic Fibrosis: A Case-Control Study

Background.

TheBurkholderia cepaciacomplex is associated with colonization or disease in patients with cystic fibrosis (CF). For patients without CF, this complex is poorly understood apart from its presence in occasional point source outbreaks.

Objective.

To investigate risk factors forB. cepaciabacteremia in hospitalized, intensive care unit patients without CF.

Methods.

We identified patients with 1 or more blood cultures positive forB. cepaciabetween May 1, 1996, and March 31, 2002, excluding those with CF. Control patients were matched to case patients by ward, duration of hospitalization, and onset date of bacteremia. Matched analyses were used to identify risk factors forB. cepaciabacteremia.

Results.

We enrolled 40 patients withB. cepaciabacteremia into the study. No environmental or other point source forB. cepaciacomplex was identified, although horizontal spread was suspected. Implementation of contact precautions was effective in decreasing the incidence ofB. cepaciabacteremia. We selected 119 matched controls. Age, sex, and race were similar between cases and controls. In multivariable analysis, renal failure that required dialysis, recent abdominal surgery, 2 or more bronchoscopic procedures before detection ofB. cepaciabacteremia, tracheostomy, and presence of a central line before detection ofB. cepaciabacteremia were independently associated with development ofB. cepaciabacteremia, whereas presence of a percutaneous feeding tube was associated with a lower risk of disease.

Conclusions.

B. cepaciacomplex is an important emerging group of nosocomial pathogens in patients with and patients without CF. Nosocomial spread is likely facilitated by cross-transmission, frequent pulmonary procedures, and central venous access. Infection control measures appear useful for limiting the spread of virulent, transmissible clones ofB. cepaciacomplex.

Cluster of Pseudoinfections withBurkholderia cepaciaAssociated with a Contaminated Washer-Disinfector in a Bronchoscopy Unit

In December 2008, bronchoalveolar lavage fluid samples obtained from 3 patients were positive forBurkholderia cepaciacomplex on culture. Samples obtained from bronchoscopes and rinse-water samples obtained from the washer-disinfector were found to be positive forB. cepaciacomplex. The cause of this pseudo-outbreak was that the washer-disinfector was installed without the required antibacterial filter.

Non-fermentative gram-negative bacteria in hospital tap water and water used for haemodialysis and bronchoscope flushing: prevalence and distribution of antibiotic resistant strains

This study provides a detailed description of the distribution of non-fermentative gram-negative bacteria (NFGNB) collected in water sources (tap water and water used for haemodialysis and bronchoscope flushing) from different wards of a tertiary care hospital. The aim is to identify risk practices for patients or to alert clinicians to the possible contamination of environment and medical devices. The resistance profile of NFGNB environmental isolates has shown that more than half (55.56%) of the strains isolated were resistant to one or more antibiotics tested in different antimicrobial categories. In particular, 38.89% of these strains were multidrug resistant (MDR) and 16.67% were extensively drug resistant (XDR). The most prevalent bacterial species recovered in water samples were Pseudomonas aeruginosa, Pseudomonas fluorescens, Ralstonia pickettii and Stenotrophomonas maltophilia. Analysis of antibiotic resistance rates has shown remarkable differences between Pseudomonadaceae (P. aeruginosa and P. fluorescens) and emerging pathogens, such as S. maltophilia and R. pickettii. Multidrug resistance can be relatively common among nosocomial isolates of P. aeruginosa, which represent the large majority of clinical isolates; moreover, our findings highlight that the emergent antibiotic resistant opportunistic pathogens, such as R. pickettii and S. maltophilia, isolated from hospital environments could be potentially more dangerous than other more known waterborne pathogens, if not subjected to surveillance to direct the decontamination procedures.

Seeking the source of Pseudomonas aeruginosa infections in a recently opened hospital: an observational study using whole-genome sequencing

OBJECTIVES

Pseudomonas aeruginosa is a common nosocomial pathogen responsible for significant morbidity and mortality internationally. Patients may become colonised or infected with P. aeruginosa after exposure to contaminated sources within the hospital environment. The aim of this study was to determine whether whole-genome sequencing (WGS) can be used to determine the source in a cohort of burns patients at high risk of P. aeruginosa acquisition.

STUDY DESIGN

An observational prospective cohort study.

SETTING

Burns care ward and critical care ward in the UK.

PARTICIPANTS

Patients with >7% total burns by surface area were recruited into the study.

METHODS

All patients were screened for P. aeruginosa on admission and samples taken from their immediate environment, including water. Screening patients who subsequently developed a positive P. aeruginosa microbiology result were subject to enhanced environmental surveillance. All isolates of P. aeruginosa were genome sequenced. Sequence analysis looked at similarity and relatedness between isolates.

RESULTS

WGS for 141 P. aeruginosa isolates were obtained from patients, hospital water and the ward environment. Phylogenetic analysis revealed eight distinct clades, with a single clade representing the majority of environmental isolates in the burns unit. Isolates from three patients had identical genotypes compared with water isolates from the same room. There was clear clustering of water isolates by room and outlet, allowing the source of acquisitions to be unambiguously identified. Whole-genome shotgun sequencing of biofilm DNA extracted from a thermostatic mixer valve revealed this was the source of a P. aeruginosa subpopulation previously detected in water. In the remaining two cases there was no clear link to the hospital environment.

CONCLUSIONS

This study reveals that WGS can be used for source tracking of P. aeruginosa in a hospital setting, and that acquisitions can be traced to a specific source within a hospital ward.

Carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter baumannii in the nosocomial setting in Latin America

Increasing prevalence of carbapenem-resistant Pseudomonas aeruginosa and Acinetobacter baumannii strains in the nosocomial setting in Latin America represents an emerging challenge to public health, as the range of therapeutic agents active against these pathogens becomes increasingly constrained. We review published reports from 2002 to 2013, compiling data from throughout the region on prevalence, mechanisms of resistance and molecular epidemiology of carbapenem-resistant strains of P. aeruginosa and A. baumannii. We find rates of carbapenem resistance up to 66% for P. aeruginosa and as high as 90% for A. baumannii isolates across the different countries of Latin America, with the resistance rate of A. baumannii isolates greater than 50% in many countries. An outbreak of the SPM-1 carbapenemase is a chief cause of resistance in P. aeruginosa strains in Brazil. Elsewhere in Latin America, members of the VIM family are the most important carbapenemases among P. aeruginosa strains. Carbapenem resistance in A. baumannii in Latin America is predominantly due to the oxacillinases OXA-23, OXA-58 and (in Brazil) OXA-143. Susceptibility of P. aeruginosa and A. baumannii to colistin remains high, however, development of resistance has already been detected in some countries. Better epidemiological data are needed to design effective infection control interventions.

Evaluation of reprocessing medical devices in 14 German regional hospitals and at 27 medical practitioners' offices within the European context - consequences for European harmonization

Safe reprocessing of medical devices through cleaning, disinfection, and sterilization is essential for the prevention of health care associated infections (HAI) and to guarantee patient safety. Several studies detected residual contamination and even severe infections of patients, despite carrying out reprocessing. To develop appropriate solutions, the existing situation in Germany and selected European countries was analyzed. Additionally, in 27 medical practitioners' offices and 14 hospitals, the true practice of reprocessing was analyzed using a questionnaire, a checklist, and inspection on site. A structured analysis of potential alternatives to the internal reprocessing was conducted within the German and European context. The results indicate that the conditions for the execution of the reprocessing process in the analyzed health facilities in southern Hesse (Germany) do not satisfy legal requirements. The detected deficiencies were consistent with other reports from Germany and Europe. The analysis gave insight into several reasons for the detected deficiencies. The three main reasons were the high costs for proper implementation, the subjective value assigned to the reprocessing unit in health care facilities, and deficits in monitoring by the health authority. Throughout the European Union, a similar regulatory framework for the performance of the reprocessing process exists, while the environment, structures of the health systems and administrative supervision vary significantly. The German states as well as selected European countries are currently discussing the challenges of increased quality-assured execution of the reprocessing process. For instance, the same supervisory system for hospitals and medical practitioners should be established at an equal standard. Alternatives such as the use of single-use medical devices, outsourcing the decontamination processes, or the cooperation of health facilities may be considered. This paper also discusses economic and ecological aspects. Finally, different options are recommended to ensure the exclusive use of reliable medical devices for surgical procedures that guarantee an adequate standard of patient safety within economic constraints.

Klebsiella spp. in endoscopy-associated infections: we may only be seeing the tip of the iceberg

PURPOSE

Two endoscopy-associated nosocomial outbreaks caused by carbapenemase-producing Klebsiella pneumoniae (CPKP) were recently observed in two German hospitals. In this study, we performed a systematic search of the medical literature in order to elucidate the epidemiology of Klebsiella spp. in endoscopy-associated outbreaks.

METHODS

Medline, the Outbreak Database ( http://www.outbreak-database.com ) and reference lists of articles extracted from these databases were screened for descriptions of endoscopy-associated nosocomial outbreaks. The data extracted and analysed were: (1) the type of medical department affected; (2) characterisation of pathogen to species and conspicuous resistance patterns (if applicable); (3) type of endoscope and the grade of its contamination; (4) number and the types of infections; (5) actual cause of the outbreak.

RESULTS

A total of seven nosocomial outbreaks were identified, of which six were outbreaks of endoscopic retrograde cholangiopancreatography-related infections and caused by contaminated duodenoscopes. Including our own outbreaks in the analysis, we identified one extended-spectrum beta-lactamase-producing K. pneumoniae strain and six CPKP strains. Insufficient reprocessing after the use of the endoscope was the main reason for subsequent pathogen transmission.

CONCLUSIONS

There were only two reports of nosocomial outbreaks due to Klebsiella spp. in the first three decades of endoscopic procedures, but seven additional outbreaks of this kind have been reported within the last 4 years. It is very likely that many of such outbreaks have been missed in the past because this pathogen belongs to the physiological gut flora. However, with the emergence of highly resistant (carbapenemase-producing) strains, strict adherence to infection control guidelines is more important than ever.

Transmission of infection by flexible gastrointestinal endoscopy and bronchoscopy

Flexible endoscopy is a widely used diagnostic and therapeutic procedure. Contaminated endoscopes are the medical devices frequently associated with outbreaks of health care-associated infections. Accurate reprocessing of flexible endoscopes involves cleaning and high-level disinfection followed by rinsing and drying before storage. Most contemporary flexible endoscopes cannot be heat sterilized and are designed with multiple channels, which are difficult to clean and disinfect. The ability of bacteria to form biofilms on the inner channel surfaces can contribute to failure of the decontamination process. Implementation of microbiological surveillance of endoscope reprocessing is appropriate to detect early colonization and biofilm formation in the endoscope and to prevent contamination and infection in patients after endoscopic procedures. This review presents an overview of the infections and cross-contaminations related to flexible gastrointestinal endoscopy and bronchoscopy and illustrates the impact of biofilm on endoscope reprocessing and postendoscopic infection.

Device-Related Infections in Critically Ill Patients. Part II: Prevention of Ventilator-Associated Pneumonia and Urinary Tract Infections

Device utilization in critically ill patients is responsible for a high risk of complications such as catheter-related bloodstream infections (CRBSI), ventilator-associated pneumonia (VAP) and urinary tract infections (UTI). In this article we will review the current status of data regarding the prevention of VAP and UTI. The results of the more recent (5 years) randomized controlled trials are reviewed and discussed. General recommendations include staff education and use of a surveillance program with a restrictive antibiotic policy. Adequate time must be allowed for hand washing and barrier precautions must always be used during device manipulation. Specific measures for VAP prevention are: 1) use of multi-use, closed-system suction catheters; 2) no routine change of the breathing circuit; 3) lubrication of the cuff of the endotracheal tube (ET) with a water-soluble gel; 4) maintenance of patient in semi-recumbent position to improve chest physiotherapy in intubated patients. Specific measures for UTI prevention include: 1) use of a catheter-valve instead of a standard drainage system; 2) use of a silver-alloy, hydro gel-coated latex urinary catheter instead of uncoated catheters. Biofilm represents a new variable: the capacity of bacteria to organize a biofilm on a device surface can explain the difficulty in preventing and eradicating an infection in a critically ill patient. More clinical trials are needed to verify the efficacy of prevention measures of ICU infections.

New developments in reprocessing semicritical items

Semicritical medical devices are defined as items that come into contact with mucous membranes or nonintact skin (eg, gastrointestinal endoscopes). Such medical devices require minimally high-level disinfection. Because many of these items are temperature sensitive, low-temperature chemical methods must be used rather than steam sterilization. Strict adherence to current guidelines is required because more outbreaks have been linked to inadequately cleaned or disinfected endoscopes undergoing high-level disinfection than any other medical device.

A bronchofiberoscopy-associated outbreak of multidrug-resistant Acinetobacter baumannii in an intensive care unit in Beijing, China

Background

Bronchofiberscopy, a widely used procedure for the diagnosis of various pulmonary diseases within intensive care units, has a history of association with nosocomial infections. Between September and November 2009, an outbreak caused by multidrug-resistant Acinetobacter baumannii (MDR-Ab) was observed in the intensive care unit of a tertiary care hospital in Beijing, China. This study is aimed to describe the course and control of this outbreak and investigate the related risk factors.

Methods

Clinical and environmental sampling, genotyping with repetitive extragenic palindromic polymerase chain reaction (REP-PCR), and case–control risk factor analysis were performed in the current study.

Results

During the epidemic period, 12 patients were infected or colonized with MDR-Ab. Sixteen (72.7%) of twenty-two MDR-Ab isolates from the 12 patients and 22 (84.6%) of 26 MDR-Ab isolates from the bronchofiberscope and the healthcare-associated environment were clustered significantly into a major clone (outbreak MDR-Ab strain) by REP-PCR typing. Seven patients carrying the outbreak MDR-Ab strain were defined as the cases. Six of the seven cases (83%) received bronchofiberscopy versus four of the 19 controls (21%) (odds ratio, 22.5; 95% confidence interval, 2.07–244.84; P = 0.005). Several potential administrative and technical problems existed in bronchofiberscope reprocessing.

Conclusions

Bronchofiberscopy was associated with this MDR-Ab outbreak. Infection control precautions including appropriate bronchofiberscope reprocessing and environmental decontamination should be strengthened.

Biofilms of a Bacillus subtilis hospital isolate protect Staphylococcus aureus from biocide action

The development of a biofilm constitutes a survival strategy by providing bacteria a protective environment safe from stresses such as microbicide action and can thus lead to important health-care problems. In this study, biofilm resistance of a Bacillus subtilis strain (called hereafter ND_medical) recently isolated from endoscope washer-disinfectors to peracetic acid was investigated and its ability to protect the pathogen Staphylococcus aureus in mixed biofilms was evaluated. Biocide action within Bacillus subtilis biofilms was visualised in real time using a non-invasive 4D confocal imaging method. The resistance of single species and mixed biofilms to peracetic acid was quantified using standard plate counting methods and their architecture was explored using confocal imaging and electronic microscopy. The results showed that the ND_medical strain demonstrates the ability to make very large amount of biofilm together with hyper-resistance to the concentration of PAA used in many formulations (3500 ppm). Evidences strongly suggest that the enhanced resistance of the ND_medical strain was related to the specific three-dimensional structure of the biofilm and the large amount of the extracellular matrix produced which can hinder the penetration of peracetic acid. When grown in mixed biofilm with Staphylococcus aureus, the ND_medical strain demonstrated the ability to protect the pathogen from PAA action, thus enabling its persistence in the environment. This work points out the ability of bacteria to adapt to an extremely hostile environment, and the necessity of considering multi-organism ecosystems instead of single species model to decipher the mechanisms of biofilm resistance to antimicrobials agents.

A large sustained endemic outbreak of multiresistant Pseudomonas aeruginosa: a new epidemiological scenario for nosocomial acquisition

Background

Studies of recent hospital outbreaks caused by multiresistant P.aeruginosa (MRPA) have often failed to identify a specific environmental reservoir. We describe an outbreak due to a single clone of multiresistant (MR) Pseudomonas aeruginosa (PA) and evaluate the effectiveness of the surveillance procedures and control measures applied.

Methods

Patients with MRPA isolates were prospectively identified (January 2006-May 2008). A combined surveillance procedure (environmental survey, and active surveillance program in intensive care units [ICUs]) and an infection control strategy (closure of ICU and urology wards for decontamination, strict compliance with cross-transmission prevention protocols, and a program restricting the use of carbapenems in the ICUs) was designed and implemented.

Results

Three hundred and ninety patients were identified. ICU patients were the most numerous group (22%) followed by urology patients (18%). Environmental surveillance found that 3/19 (16%) non-ICU environmental samples and 4/63 (6%) ICU samples were positive for the MRPA clonal strain. In addition, active surveillance found that 19% of patients were fecal carriers of MRPA. Significant changes in the trends of incidence rates were noted after intervention 1 (reinforcement of cleaning procedures): -1.16 cases/1,000 patient-days (95%CI -1.86 to -0.46; p = 0.003) and intervention 2 (extensive decontamination): -1.36 cases/1,000 patient-days (95%CI -1.88 to -0.84; p < 0.001) in urology wards. In addition, restricted use of carbapenems was initiated in ICUs (January 2007), and their administration decreased from 190-170 DDD/1,000 patient-days (October-December 2006) to 40-60 DDD/1,000 patient-days (January-April 2007), with a reduction from 3.1 cases/1,000 patient-days in December 2006 to 2.0 cases/1,000 patient-days in May 2007. The level of initial carbapenem use rose again during 2008, and the incidence of MRPA increased progressively once more.

Conclusions

In the setting of sustained MRPA outbreaks, epidemiological findings suggest that patients may be a reservoir for further environmental contamination and cross-transmission. Although our control program was not successful in ending the outbreak, we think that our experience provides useful guidance for future approaches to this problem.

National athletic trainers' association position statement: skin diseases

OBJECTIVE

To present recommendations for the prevention, education, and management of skin infections in athletes.

BACKGROUND

Trauma, environmental factors, and infectious agents act together to continually attack the integrity of the skin. Close quarters combined with general poor hygiene practices make athletes particularly vulnerable to contracting skin diseases. An understanding of basic prophylactic measures, clinical features, and swift management of common skin diseases is essential for certified athletic trainers to aid in preventing the spread of infectious agents.

RECOMMENDATIONS

These guidelines are intended to provide relevant information on skin infections and to give specific recommendations for certified athletic trainers and others participating in athletic health care.

Disseminated toxoplasmosis in an immunocompetent patient from Peruvian Amazon

We report a case of severe toxoplasmosis in an immunocompetent patient, characterized by pneumonia, retinochoroiditis, hepatitis and myositis. Diagnosis was confirmed by serology, T. gondii in thick blood smear and presence of bradyzoites in muscle biopsy. Treatment with pyrimethamine plus sulfadoxine was successful but visual acuity and hip extension were partially recovered. This is the first case report of severe toxoplasmosis in an immunocompetent patient from Peru.

[Evolution of antimicrobial resistance against Pseudomonas aeruginosa in a French university hospital between 2002 and 2006]

AIM OF STUDY

Monitor evolution of antibiotic resistance of Pseudomonas aeruginosa from 2002 to 2006 in our hospital to optimize antibiotherapy.

PATIENTS AND METHOD

The infections/colonizations with P. aeruginosa have been identified by the hospital's informatic database. Bacteriological samples realized 48hours after patient's admission was considered as nosocomial. A Cochran-Armitage test was conducted to assess the evolution of resistance.

RESULTS

During this period, 2098 infections/colonizations with P. aeruginosa have been identified. Bacteriological samples (68.5%) were nosocomial. Among the beta-lactam antibiotics, ceftazidime and imipenem were the most active (R=16.8% and 15.2%, respectively), followed by piperacillin and piperacillin-tazobactam (R=24.8%, 18.4%, respectively). Amikacin and tobramycin were more active than gentamicin (R=19.9%; 22.2% and 40.6%, respectively). 28.9% of strains were resistant to ciprofloxacin. Nosocomial strains were significantly more resistant than non-hospital strains: ceftazidime: 17.9% versus 14.2%, p=0.0346; ticarcillin-clavulanic acid: 47.5% versus 39.6%, p=0.0009; piperacillin-tazobactam: 20.0% versus 14.8%, p=0.0046; ciprofloxacin: 30.7% versus 25.2%, p=0.0112. A significant increase in the resistance of nosocomial strains to ceftazidime, ticarcillin-clavulanic acid and piperacillin-tazobactam was noted. Resistance from non-hospital strains to fluoroquinolones, aminoglycosides, ceftazidime, piperacillin and ticarcillin-clavulanic acid decreased significantly.

CONCLUSION

P. aeruginosa is a predominantly nosocomial microorganism. There is a decrease of resistance for non-hospital strains. But the resistance of nosocomial strains to antibiotics widely prescribed in hospital is worrying.

Outbreak of Pseudomonas aeruginosa infection associated with contamination of a flexible bronchoscope

BACKGROUND

A cluster of patients with respiratory cultures positive for Pseudomonas aeruginosa with a unique antibiogram was observed during June and July 2007 at a 1,000-bed urban teaching hospital in Atlanta, Georgia. These P. aeruginosa isolates were recovered from bronchoscopically obtained specimens.

METHODS

A cross-sectional study was performed to assess whether the cluster was associated with exposure to a particular bronchoscope (B1); cultures from specimens from the bronchoscopes and the environment were obtained, and the P. aeruginosa isolate type was determined using pulsed-field gel electrophoresis (PFGE). Records of patients exposed to B1 during the cluster period were reviewed.

RESULTS

Twelve patients with a culture positive for P. aeruginosa with the unique susceptibility pattern were identified in June-July 2007. No cases were documented from March 1 through May 31, 2007. Culture specimens obtained from B1 after high-level disinfection revealed P. aeruginosa, prompting removal of B1 from service on July 23, 2007. No cases occurred after that date. Eleven (55%) of 20 patients who were exposed to B1 during the cluster period had a culture positive for P. aeruginosa, compared with 1 (2%) of 53 patients who were exposed to other bronchoscopes (P < .001). PFGE patterns for P. aeruginosa isolates obtained from case patients and from B1 were identical. An engineering evaluation of B1 documented several internal damages. Two (10.5%) of 19 patients exposed to B1 during the cluster period may have developed P. aeruginosa infection following exposure to B1.

CONCLUSIONS

An outbreak or pseudo-outbreak of P. aeruginosa infection occurred in association with use of a damaged bronchoscope. Periodic engineering maintenance may be needed to prevent bronchoscope contamination that is resistant to high-level disinfection.

Modeling microbial survival in buildup biofilm for complex medical devices

Background

Flexible endoscopes undergo repeated rounds of patient-use and reprocessing. Some evidence indicates that there is an accumulation or build-up of organic material that occurs over time in endoscope channels. This "buildup biofilm" (BBF) develops as a result of cyclical exposure to wet and dry phases during usage and reprocessing. This study investigated whether the BBF matrix represents a greater challenge to disinfectant efficacy and microbial eradication than traditional biofilm (TBF), which forms when a surface is constantly bathed in fluid.

Methods

Using the MBEC (Minimum Biofilm Eradication Concentration) system, a unique modelling approach was developed to evaluate microbial survival in BBF formed by repetitive cycles of drying, disinfectant exposure and re-exposure to the test organism. This model mimics the cumulative effect of the reprocessing protocol on flexible endoscopes. Glutaraldehyde (GLUT) and accelerated hydrogen peroxide (AHP) were evaluated to assess the killing of microbes in TBF and BBF.

Results

The data showed that the combination of an organic matrix and aldehyde disinfection quickly produced a protective BBF that facilitated high levels of organism survival. In cross-linked BBF formed under high nutrient conditions the maximum colony forming units (CFU) reached ~6 Log₁₀ CFU/peg. However, if an oxidizing agent was used for disinfection and if organic levels were kept low, organism survival did not occur. A key finding was that once established, the microbial load of BBF formed by GLUT exposure had a faster rate of accumulation than in TBF. The rate of biofilm survival post high-level disinfection (HLD) determined by the maximum Log₁₀CFU/initial Log₁₀CFU for E. faecalis and P. aeruginosa in BBF was 10 and 8.6 respectively; significantly different compared to a survival rate in TBF of ~2 for each organism. Data from indirect outgrowth testing demonstrated for the first time that there is organism survival in the matrix. Both TBF and BBF had surviving organisms when GLUT was used. For AHP survival was seen less frequently in BBF than in TBF.

Conclusion

This BBF model demonstrated for the first time that survival of a wide range of microorganisms does occur in BBF, with significantly more rapid outgrowth compared to TBF. This is most pronounced when GLUT is used compared to AHP. The data supports the need for meticulous cleaning of reprocessed endoscopes since the presence of organic material and microorganisms prevents effective disinfection when GLUT and AHP are used. However, cross-linking agents like GLUT are not as effective when there is BBF. The data from the MBEC model of BBF suggest that for flexible endoscopes that are repeatedly used and reprocessed, the assurance of effective high-level disinfection may decrease if BBF develops within the channels.

Evidence-based spectrum of antimicrobial activity for disinfection of bronchoscopes

Summary

Processing of bronchoscopes after a physical examination has to eliminate all micro-organisms that could have contaminated the endoscope and that may harm the following patient. The aim of this analysis is to define those micro-organisms that may contaminate the bronchoscope during the examination and that may cause disease in other patients.

Methods

Research of literature and analysis of laboratory data.

Results

During the passage of the respiratory tract the bronchoscope will be contaminated by the physiological flora of oral cavity, nasopharynx, trachea, bronchi, and pulmonary tissues. Whilst the oral cavity, the nasopharynx and the pharynx are the habitat for a great variety of bacteria the lower respiratory tract is virtually free of micro-organisms. However, in ventilated patients trachea and bronchi can become colonized as the result of bypassing the cleansing effect of the ciliated epithelium. In addition all agents that can cause bronchitis or pneumonia in immunocompromised or otherwise healthy individuals are potential contaminants of bronchoscopes. These microorganisms include bacteria, mycobacteria, yeasts and moulds, enveloped and non-enveloped viruses and rarely parasites.

The bronchoscopic procedure can result in epithelial injury with subsequent bleeding. Therefore, all blood-borne pathogens, e.g. HIV or HBV are also potential contaminants of the bronchoscope.

There are several reports of transmission of micro-organisms due to incomplete or faulty cleaning and disinfection procedures of bronchoscopes. These incidents include nearly all classes of micro-organisms but not parasites or viruses. However, the incubation period of viruses can be long and the association between bronchoscopy and infection may be obscure.

Endospore forming micro-organisms and parasites are not part of the normal flora of the respiratory tract and may rarely cause disease, usually only in severely immunocompromised patients, but transmission of such organisms by bronchoscopy has never been reported.

Conclusion

The antimicrobial activity of the disinfection process, including chemical disinfectants for endoscopes has to include bacteria, fungi and viruses. Sporicidal activity may be only warranted in specific patient populations, i.e. after bronchoscopy of suspected anthrax patients or before examination of severely immunocompromised patients.

An outbreak of Pseudomonas aeruginosa infections following thoracic surgeries occurring via the contamination of bronchoscopes and an automatic endoscope reprocessor

An outbreak of Pseudomonas aeruginosa infections occurred after thoracic surgeries performed between May and June 2003. Clinical data of seven patients were reviewed and the fact was revealed that bronchoscopes were used during endotracheal intubation for one-lung ventilation in most patients. P. aeruginosa was recovered from the sputum of these patients at a very early stage post-operation. Environmental samples from bronchoscopes and an automated endoscope reprocessor (AER) were cultured and P. aeruginosa strains were recovered from all of them. All of these strains were confirmed to be identical by pulsed-field gel electrophoresis (PFGE). Inspection of the sterilization cycles of bronchoscopes revealed inappropriate management of bronchoscopes and a flaw in the AER; once its detergent tank was contaminated, it was not possible to disinfect it. After all the bronchoscopes had been disinfected, and the washing machine had been remodeled, with the washing process confirmed to be appropriate, the outbreak finally ended. This outbreak had two causes, a flaw in the AER and inappropriate disinfection procedures. Outbreaks associated with bronchoscopic examinations have been reported elsewhere. Bronchoscopes are widely used to facilitate endotracheal intubation, especially for one-lung anesthesia. Although they are used for only a short time during anesthetic procedures, we should handle them more carefully.

Safety of bronchoalveolar lavage in young children with cystic fibrosis

OBJECTIVE

Our aim was to determine the safety of BAL in young children <6 years with CF.

METHODS

As part of a multi-center study of BAL-directed therapy, children with CF < 6 years had one or more BALs between September 1999 and December 2005. Adverse events were recorded intraoperatively and for 24 hr thereafter. Clinical characteristics before BAL, findings at bronchoscopy and BAL results were assessed as risk factors for adverse events.

RESULTS

333 BALs were conducted in 107 (56 males) children, median age 23.5 (range 1.6-67.5) months, including 170 (51%) for pulmonary exacerbation. 29 BALs (8.7%) were followed by fever >or=38.5 degrees C and 10 (3%) had clinically significant episodes (five intraoperative hemoglobin desaturations to <90% requiring intervention, one tachyarrhythmia, two needing post-operative supplemental oxygen, one hospitalization for stridor). Two contaminated bronchoscopes were detected. 180 minor adverse events were recorded in 174 (52%) BAL procedures (137 altered cough, 41 fever <38.5 degrees C). Low percentage BAL return (P = 0.002) and focal bronchitis (P = 0.02) were associated with clinically significant deterioration. Multivariable analysis identified Streptococcus pneumoniae (OR 22.3; 95% confidence interval (CI); 6.9,72), Pseudomonas aeruginosa (OR 2.4; 95% CI 1.0, 5.8), respiratory signs (OR 5.0; 95% CI 1.7, 14.6) and focal bronchitis (OR 5.9; 95% CI 1.2, 29.8) as independent risk factors for post-bronchoscopy fever >or=38.5 degrees C.

CONCLUSIONS

Adverse events are common with BAL in young CF children, but are usually transient and well tolerated. Parents should be counseled that signs of a pre-existing lower respiratory infection are associated with increased risk of post-BAL fever.

Point-of-use water filtration reduces endemic Pseudomonas aeruginosa infections on a surgical intensive care unit

BACKGROUND

Endemic infections because of Pseudomonas aeruginosa were observed on a surgical intensive care unit (ICU) for a period of >24 months. Tap water probing revealed persistent colonization of all ICU water taps with a single P aeruginosa clonotype.

METHODS

Water outlets of the ICU were equipped with disposable point-of-use water filters, changed in weekly and, later, 2-week intervals. To delineate the effect of the filters, 4 study approaches were followed: (1) a descriptive analysis of the incidence of P aeruginosa colonizations and infections, (2) microbiologic examinations of tap water before and after installation of the filters, (3) a comparative cohort analysis of representative patient samples from the prefilter and postfilter time periods, and (4) an analysis of general ward variables for the 2 periods.

RESULTS

(1) The mean monthly rate (+/-SD) of P aeruginosa infection/colonization episodes was 3.9 +/- 2.4 in the prefilter and 0.8 +/- 0.8 in the postfilter period. P aeruginosa colonizations were reduced by 85% (P < .0001) and invasive infections by 56% (P < .0003) in the postfilter period. (2) Microbiologic examinations of tap water revealed growth of P aeruginosa in 113 of 117 (97%) samples collected during the prefilter period, compared with 0 of 52 samples taken from filter-equipped taps. (3) In the comparative cohort analysis, a number of patient-related variables were significantly associated with P aeruginosa colonization/infection. Considering these variables in a multivariate analysis, belonging to the postfilter cohort was the factor most strongly associated with a reduced risk of P aeruginosa positivity (relative risk, 0.04; P = .0002). (4) General ward variables such as bed occupancy, personnel-to-patient ratio, or microbiologic culturing density did not differ significantly between the 2 periods.

CONCLUSION

Taking into account various patient-related and general ward variables, point-of-use water filtration was associated with a significant reduction of chronically endemic P aeruginosa colonizations/infections on a surgical ICU.

Survival of enveloped and non-enveloped viruses on surfaces compared with other micro-organisms and impact of suboptimal disinfectant exposure

Survival of enveloped and non-enveloped viruses was compared with that of bacteria, yeasts and mycobacteria when dried on the surface of polyvinyl chloride test carriers in the presence or absence of an organic matrix. The efficacy of glutaraldehyde and accelerated hydrogen peroxide (AHP) disinfectants was evaluated. Reovirus, a non-enveloped virus, persisted and had a RF of 2 after 30 days whereas Enterococcus faecalis had an RF of 4 over the same time period. The other test organisms (Sindbis virus, Pseudomonas aeruginosa, Mycobacterium chelonae and Candida albicans) had variable survivals but none survived as long as 30 days. Both glutaraldehyde and AHP were effective at manufactures' recommended dilutions for high-level disinfection. However, only 7% AHP eliminated a glutaraldehyde-resistant strain of M. chelonae. Breakthrough survival was detected at 0.1% glutaraldehyde and 0.05% AHP for all organisms tested. Our data emphasise the need for effective cleaning and disinfection in nosocomial settings to prevent pathogen transmission.

Microbiological monitoring of endoscopes: 5-year review

Periodic microbiological monitoring of endoscopes is a recommendation of the Gastroenterological Society of Australia (GENSA). The aim of monitoring has been to provide quality assurance of the cleaning and disinfection of endoscopes; however, there is controversy regarding its frequency. This lack of consensus stimulated a review of the experience within our health service. At Southern Health, routine microbiological sampling has involved 4-weekly monitoring of bronchoscopes, duodenoscopes and automated flexible endoscope reprocessors (AFER), and 3-monthly monitoring of all other gastrointestinal endoscopes. Records of testing were reviewed from 1 January 2002 until 31 December 2006. A literature review was conducted, cost analysis performed and positive cultures investigated. There were 2374 screening tests performed during the 5-year period, including 287 AFER, 631 bronchoscopes for mycobacteria and 1456 endoscope bacterial screens. There were no positive results of the AFER or bronchoscopes for mycobacteria. Of the 1456 endoscopic bacterial samples, six were positive; however, retesting resulted in no growth. The overall cost of tests performed and cost in time for nursing staff to collect the samples was estimated at $AUD 100,400. Periodic monitoring of endoscopes is both time-consuming and costly. Our review demonstrates that AFER (Soluscope) perform well in cleaning endoscopes. Based on our 5-year experience, assurance of quality for endoscopic use could be achieved through process control as opposed to product control. Maintenance of endoscopes and AFER should be in accordance with the manufacturer's instructions and microbiological testing performed on commissioning, annually and following repair. Initial prompt manual leak testing and manual cleaning followed by mechanical leak testing, cleaning and disinfection should be the minimum standard in reprocessing of endoscopes.

[Diagnostic flexible bronchoscopy. Recommendations of the Endoscopy Working Group of the French Society of Pulmonary Medicine]

These guidelines on flexible bronchoscopy depict important clues to be known and taken into account while practicing flexible bronchoscopy, in adult, except in emergency situations. This is a practical clarification. Safety conditions, complications, anesthesia, infectious risks, cleaning and disinfection are detailed from a review of the literature. Intensive care practice of bronchoscopy requires more attention due to higher risks patients and is discussed extensively. Standards and performances of the various sampling techniques complete this work. Indications for bronchoscopy, therapeutic and paediatric bronchoscopy are not covered in these guidelines.

[Five years of the Robert Koch Institute guidelines for reprocessing of flexible endoscopes. A look back and a look forward]

In a short review the national and international reception of the German guidelines for reprocessing flexible endoscopes is presented. The recommendations of the guidelines are discussed in view of recent knowledge on old problems such as prion inactivation and new infectious diseases and new microorganisms such as SARS, avian influenza and C. difficile. New disinfectants and new methods for endoscope disinfection are mentioned, the importance of careful cleaning is underlined. The German guidelines of the Robert Koch Institute and the US Multi-Society guidelines, published in 2003, are compared. The discrepancies concerning recommendations for water quality for final rinsing and need of microbiological controls of endoscope reprocessing are stressed. Aspects not mentioned in the German guidelines, e.g. duration of storage after reprocessing and risk of infection transmission by the endo-washer, are discussed.

Neumopatías hospitalarias en pacientes con ventilación mecánica

Las neumopatías son la primera causa de infección hospitalaria en reanimación. Las neumopatías hospitalarias en los pacientes con ventilación mecánica (NHPVM) ocurren después de al menos 48 horas de ventilación mecánica invasiva. Su mecanismo es multifactorial, pero la opinión predominante es que obedecen a una inhalación posterior a la colonización orofaríngea, gástrica o traqueal. El retraso en la manifestación permite clasificar las NHPVM en precoces o tardías según se desarrollen antes o después del 5.° día de ventilación mecánica. La clínica puede ayudar al diagnóstico, sobre todo mediante la CPIS (Clinical Pulmonary Infection Score) y también es útil el lavado broncoalveolar (LBA), que parece la mejor prueba para el diagnóstico microbiológico. El diagnóstico diferencial se plantea con una neumopatía no bacteriana o incluso no infecciosa (neoplásica, inflamatoria, fibrosante) en la que siempre debe plantearse la búsqueda de otro foco infeccioso en función de la orientación clínica inicial o del fracaso de la antibioticoterapia. El uso preferente de la ventilación no invasiva, cuando es posible, parece que ayuda a prevenir el desarrollo de la neumopatía hospitalaria. La posición inclinada 30-45° del paciente es la única medida preventiva verdaderamente validada en las NHPVM. El tratamiento curativo de las neumopatías bacterianas descansa por lo general en un tratamiento antibiótico doble, que puede orientarse por los datos de muestras obtenidas con métodos no invasivos como las aspiraciones traqueales efectuadas de forma periódica y sistemática. La duración del tratamiento es discutible, pero los últimos datos apoyan un tratamiento con antibióticos relativamente corto, de 8 días.

Polmoniti nosocomiali acquisite sotto ventilazione meccanica

Le polmoniti sono la prima causa di infezione nosocomiale in rianimazione. Le polmoniti nosocomiali acquisite sotto ventilazione meccanica (PNAVM) compaiono dopo almeno 48 ore di ventilazione meccanica invasiva. Il loro meccanismo è multifattoriale, ma predomina la nozione di inalazione che compare dopo una colonizzazione orofaringea, gastrica o tracheale. Il tempo di comparsa permette di classificare queste PNAVM come precoci o tardive a seconda che compaiano prima o dopo il 5° giorno di ventilazione meccanica. La diagnosi può essere aiutata dalla clinica, essenzialmente grazie al punteggio CPIS (Clinical Pulmonary Infection Score), e dal lavaggio broncoalveolare (BAL), che sembra l’esame più utile per la diagnosi microbiologica. La diagnosi differenziale con una pneumopatia non batterica o anche non infettiva (neoplastica, infiammatoria, fibrotica) o la ricerca di un altro focolaio infettivo devono sempre essere discusse in funzione dell’orientamento clinico iniziale o del fallimento della terapia antibiotica. Il ricorso preferenziale alla ventilazione non invasiva, quando possibile, sembra utile per prevenire l’insorgenza di una pneumopatia nosocomiale. La posizione semiseduta del paziente a 30–45° è la sola misura profilattica veramente validata di prevenzione delle PNAVM. Il trattamento curativo delle polmoniti batteriche si basa in genere su una doppia terapia antibiotica. Quest’ultima può essere orientata dai dati di prelievi non invasivi, come le aspirazioni tracheali, realizzate in modo periodico e sistematico. La durata del trattamento è discussa, ma gli ultimi dati sono in favore di una terapia antibiotica relativamente breve, di 8 giorni.