Stenotrophomonas maltophilia contamination of nebulizers used to deliver aerosolized therapy to inpatients with cystic fibrosis

There is circumstantial evidence that nebulizer equipment may be a source of Stenotrophomonas maltophilia for patients with cystic fibrosis. Eighty-nine inpatient nebulizers were examined for evidence of S. maltophilia contamination of which nine (10%) yielded 14 strains of the bacterium. Environmental samples were obtained from 73 different sites on the ward, of which 17 (23%) yielded a further 21 strains. Positive sites included taps, sink drains, and potable water. Genotyping using ERIC-PCR and pulsed-field gel electrophoresis revealed that two pairs of patients' nebulizers were contaminated with closely related strains. None of the S. maltophilia isolates obtained from the ward environment shared genotypes with those obtained from the nebulizers. The frequency of isolation of S. maltophilia from potable water sources on the ward suggests that contamination may result from using it to clean reusable nebulizer equipment, particularly if this is followed by inadequate drying. Although the actual source of S. maltophilia contamination of hospital-use nebulizer equipment in this study remained elusive, these results have important infection control implications.     

Genotyping of Pseudomonas aeruginosa sputum and stool isolates from cystic fibrosis patients: evidence for intestinal colonization and spreading into toilets

Three hundred and fifty-eight stool and 131 sputum specimens from 40 cystic fibrosis (CF) patients and 100 toilet sinks were investigated for occurrence of Pseudomonas aeruginosa; 67% (21/31) of the patients with chronic P. aeruginosa lung infections carried the organism repeatedly in the stool but the organism was found only once in the stools of nine uninfected patients. P. aeruginosa stool carriage was correlated to high P. aeruginosa numbers in patients' sputa. Typing of P. aeruginosa with a DNA probe showed identity of sputum and stool strains. Seven patients repeatedly carried additional stool strains, not found in the sputum, suggesting intestinal colonization. No differences were seen in the clinical state of patients with P. aeruginosa-negative stool samples and patients with positive stool samples. Toilets in households of P. aeruginosa-infected CF patients were significantly more often contaminated with P. aeruginosa (42%) than toilets in households of non-infected CF patients (20%; P less than 0.03). The study shows that P. aeruginosa-infected CF patients may harbour the organisms also in the intestinal tract, and may spread the bacteria into toilets.     

Efficient management and maintenance of ultrasonic nebulizers to prevent microbial contamination

AIM: To seek the cause of Burkholderia cepacia complex (Bcc) infection outbreak and evaluate the efficacy of new methods for nebulizer maintenance.METHODS: We investigated the annual number of Bcc isolates recovered from clinical samples in our hospital between 1999 and 2013. Swab samples were randomly collected for bacterial culture before patient use from 10 each of the two machine types in August 2001; these included 20 samples from each of the following: Drain tubes, operating water chambers, oscillators, and nebulizing chambers. In addition, 10 samples each of nebulizer solutions before and after use were cultured. For environmental investigation, 10 samples were collected from sinks in the nurse stations of the wards where patients positive for Bcc were hospitalized. Numbers of Bcc isolates were compared before and after introduction of new methods for nebulizer maintenance in October 2001. In addition, randomly amplified polymorphic DNA (RAPD) assay was applied to find the genetic divergence of the Bcc isolates obtained from clinical samples and nebulizers.RESULTS: From January 1999 to December 2013, a total of 487 Bcc isolates were obtained from clinical specimens from 181 patients. Notably, 322 (66.1%) Bcc isolates were obtained from clinical specimens from 1999 to 2001, including 244 (115 patients) from sputum and 34 (11 patients) from blood. During this period, 14 isolates were obtained from nebulizer components. Among these, six were derived from nebulizer drain tubes, five from operating water chambers, and one from the oscillator before patient use, and two from nebulizer solutions after patient use. When Bcc was isolated from the nebulizer solution after patient use, Bcc was simultaneously detected in other parts of the nebulizer. Bcc was not isolated from any nebulizer solution before use. RAPD assays revealed similar DNA profiles in isolates obtained from patients and nebulizers. Investigation revealed damaged diaphragms in many nebulizers. The new maintenance methods for nebulizers, including restriction of the usage period, thorough disinfection, and routine check for diaphragm breakage, remarkably reduced Bcc isolation (165 isolates from patients in 12 years and 0 isolate from nebulizers in periodical sampling). In particular, Bcc has been isolated from blood from only one patient since the new methods were introduced.CONCLUSION: Appropriate maintenance of ultrasonic nebulizers is crucial for preventing Bcc contamination of nebulizers and subsequent respiratory tract and blood infections.     

Impact of hypochlorite-based disinfection on bacterial contamination of cystic fibrosis patients' home-nebulisers

Nebulisers are a potential source of bacterial contamination in cystic fibrosis (CF) patients. The aims of the study were to survey patient practice regarding maintenance of home nebulisers and to assess the impact of standardised guidelines derived from a previous in-vitro study. In total, 42 CF patients were studied. During two consecutive home visits, a questionnaire regarding routine patient practice was completed by a nurse while sputum and equipment samples were taken for bacteriological analyses. The first visit took place at baseline, and the second followed the implementation of detailed instructions for cleaning and disinfecting the nebulisers using a 0.5% hypochlorite solution. The first visit identified a great diversity in routine patient practices. Commensal bacteria, environmental bacteria and potential CF pathogens contaminated 78.5%, 57.1% and 14.3% of nebulisers respectively. After hypochlorite disinfection, rate and degree of global contamination decreased significantly, but the number of CF pathogens was not affected. There was no concordance between CF pathogens isolated from patients' sputum and their equipment. We conclude that in this sample of patients, initial routine practices were varied. With regard to CF pathogens, the superiority of a hypochlorite solution over a mix of other disinfection methods was not demonstrated.     

Low level of bacterial contamination of mist tents used in home treatment of cystic fibrosis patients

Mist tents are recommended by the Stockholm cystic fibrosis (CF) centre for small children with CF. Daily disinfection of some parts of the tent with 2% acetic acid is recommended, and for other parts boiling water followed by air-drying without rinsing. The plastic tent is discarded each day. We have studied whether these prescribed routines are followed by the patients and whether they are sufficient to prevent bacterial contamination. The mist tent equipment of 20 CF patients (mean age 7 years, range 1-15 years), two of whom were chronically colonized with Pseudomonas aeruginosa, were investigated. All patients were visited at home in the morning after 6-12 hours aerosol therapy. Liquid from the nebulizing chambers and swabs from the aerosol tube were examined by culture on four different media. Seventeen of 20 patients claimed that they cleaned and disinfected the tubes every day, two patients every other day and one once a week. Seventeen of 19 claimed they cleaned and disinfected the chambers daily, one once a week and, one twice a week. No or insignificant growth was found in 16/20 aerosol tubes: moulds in three, Pseudomonas species in one. Twelve of 19 chambers showed no or insignificant growth: moulds or yeasts were present in three and Pseudomonas sp. in four. In four of the seven patients moulds or yeasts and/or Pseudomonas sp. grew both from chambers and from aerosol tubes; in the remaining three only from chambers. None of these seven patients had followed our prescribed cleaning and disinfection recommendations, the other 13 claimed they had. Of the patients whose equipment yielded Pseudomonas sp, none was colonized with these strains, although one had P. aeruginosa. We conclude that our disinfection recommendations are adequate when followed. However, our disinfection recommendations concerning the nebulizing chamber had not been followed satisfactorily. The different forms of non-compliance would not have been detected without a home visit, emphasizing the importance of such visits. The importance of drying the equipment and of using the correct concentration of acetic acid is stressed.     

Pseudomonas aeruginosa cross-colonization and persistence in patients with cystic fibrosis. Use of a DNA probe

To investigate cross-colonization with and persistence of Pseudomonas aeruginosa in cystic fibrosis (CF), 181 isolates from 76 CF patients were typed using a P. aeruginosa-specific DNA probe. Whereas sibling pairs predominantly harboured genotypically identical P. aeruginosa strains, all of the other patients harboured different strains. Seventy-nine per cent (22/31) of the infected CF patients harboured the same strains at the beginning and the end of a summer camp. A change of strains was seen in 10% (3/31) of the patients at the end of the camp. Forty-six per cent (6/13) of the patients who were apparently initially uninfected, acquired P. aeruginosa by the end of the period. Genotyping proved that strain change or acquisition was due to cross-colonization in four of nine cases. Very little P. aeruginosa was isolated from the inanimate environment. Persistence of P. aeruginosa after a temporary loss due to antibiotic therapy was seen in 12/16 paired patient strains before and after antibiotic therapy. Thus, suppression followed a flare-up seemed to occur in these patients rather than eradication and a new infection. When 35 patients were followed over a period of 6 months, 7 (20%) changed the strain in their sputum. Only one of 43 patients harboured two different P. aeruginosa strains simultaneously over a long period.     

More than 10 years' continuous oral treatment with specific immunoglobulin Y for the prevention of Pseudomonas aeruginosa infections: a case report

Immunotherapy with specific antibodies is an alternative to antibiotics for the prevention of infections in humans and animals. We have used orally administered immunoglobulin Y (IgY) preparations, purified from eggs of hens immunized with Pseudomonas aeruginosa bacteria, to prevent pulmonary P. aeruginosa infections in a group of patients with cystic fibrosis (CF). Respiratory infections are major problems for CF patients because of the thick mucus in the airways, and chronic P. aeruginosa lung infections occur in virtually all CF patients and cause morbidity and mortality. The IgY-treated group had only 2.5 P. aeruginosa-positive sputum cultures per 100 months, and none of the IgY-treated patients became chronically colonized with P. aeruginosa. In the control group, 13.7 of the cultures per 100 months were positive for P. aeruginosa, and 24% of patients became chronically colonized with P. aeruginosa. The first enrolled patient in this study has now been treated continuously for more than 10 years. During the first 8 years she only had four P. aeruginosa-positive cultures. After 8 years she became chronically infected, but still after 10 years the bacteria have not turned mucoid. No negative side effects of IgY treatment have been noted during these 10 years. To our knowledge this is the longest treatment with specific yolk antibodies for therapeutic purposes.     

Prevalence of Pseudomonas aeruginosa in households of patients with cystic fibrosis

Colonization of airways with Pseudomonas aeruginosa (PA) is known to be a risk factor for infection and adverse clinical outcome in patients with cystic fibrosis (CF). Whereas infections with PA have been linked to contaminated medical devices in hospitals, sources of colonization and infection with PA in households of patients with CF remain to be identified.

Using a standardized sampling protocol, we prospectively examined the presence of PA in 102 households of patients with CF in Germany.

PA was detected in 73 (71.6%) of 102 households. PA was detected most frequently in drains of showers (39.6%), drainpipes of hand-basins in kitchens (35.0%) and bathrooms (34.7%), and drainpipes of toilets (26.5%). Toilet seats and dish-clothes did not show PA in any household. The frequency and intensity of cleaning measures did not impact the detection rate of PA.

Results of the present study for the first time determinate the rate of contamination with PA in households of patients with CF. Future studies will determine the risk of transmission of PA from households locations to patients with CF.     

ICU多重耐药鲍曼不动杆菌医院感染暴发流行病学调查

目的调查某院重症监护室（ICU）发生的多重耐药鲍曼不动杆菌医院感染暴发的原因。方法采用前瞻性和回顾性调查相结合的方法,对2012年1月25日-2月10日该院ICU发生的10例下呼吸道感染多重耐药鲍曼不动杆菌患者进行流行病学调查。结果10例患者痰培养分离的鲍曼不动杆菌,除对头孢哌酮/舒巴坦全敏感,左氧氟沙星中度敏感外,对其他16种抗菌药物基本耐药;7例患者经治疗好转后转出ICU,3例死亡。共采集环境标本（未做清洁前）104份,其中从水龙头、治疗车、床头柜、雾化器管道、呼吸机管道和呼吸机操作屏、医务人员手等16份标本分离到鲍曼不动杆菌;16份环境标本分离的鲍曼不动杆菌耐药谱与痰培养菌株一致。经采取综合性控制措施,很好地控制了疫情。结论此次ICU多重耐药鲍曼不动杆菌医院感染暴发流行与医务人员手及医疗环境污染密切相关。     

TOBI: reducing the impact of pseudomonal infection

Pseudomonas aeruginosa infection is associated with impaired lung function and reduced life expectancy in cystic fibrosis patients. Tobramycin nebulizer solution (TOBI, Chiron Corporation Ltd, Hounslow) has been specifically formulated for use against P. aeruginosa infection in the lung.     

Is disinfection of mechanical ventilation tubing needed at home?

INTRODUCTION: Home mechanical ventilation is used to treat chronic alveolar hypoventilation. Maintenance protocols for home ventilation circuits (HVC) remain empirical and unproven. We have investigated (1) the cleanliness and sterility of the HVC used by home ventilated patients and (2) the efficiency of tubing cleaning and decontamination protocols recommended to them and used for 12 months or more. METHOD: HVC cleanliness was assessed in 39 severe restrictive ventilated patients (16 (T) tracheostomy vs. 23 (N) noninvasive) and in 7 new valves as control. In the first experiment (Exp1), a visual and bacteriologic inspection of the expiratory valve (Eva) was conducted during a consultation in our centre. Eva visual cleanliness was assessed on a 10-point scale and Eva bacteriologic contamination analysis was performed on a dry smear. In the second experiment (Exp2), these analyses were repeated after a cleaning sequence chosen at random, either chemical (ammonium-chlorhexidine complex) (A) or mechanical by dishwasher (B). RESULTS: In Exp1, 69% of Eva were dirty. Dirtiness was worse in (T) than in (N) (5.3 vs. 2; p<0.001). There was a significant positive correlation between visual cleanliness and bacteriologic contamination (r=0.56; p<0.001). Eva in group (T) were more contaminated than in group (N) (p<0.001). Eva contamination rates reached 22% in group (N) but without the presence of any potentially pathogenic organisms (PPO) and 81% in group (T) where 19% were PPO. In Exp2, EVA visual cleanliness was better after dishwasher cleaning (B) compared to chemical (A) (0.16 vs. 1.05; p<0.001) with similar bacteriological decontamination. CONCLUSION: HVC from noninvasive ventilated patients are dirty but not contaminated by PPO. We recommend washing them in a dishwasher or with detergent and hot water without specific disinfection. PPO contaminated 1/5 of invasive HVC, for which we recommend dishwasher cleaning. Decontamination is only indicated when tubing is visually very dirty or/and when tracheostomized patients are particularly sensitive to respiratory tract infections. The expiratory valve must be carefully washed specifically, with care that its balloon is not placed under water.     

0.1%苯扎溴铵消毒液污染调查与分析

目的调查0.1%苯扎溴铵消毒液被铜绿假单胞菌污染原因,以采取相应的预防控制措施。方法对制剂室环境、制剂用水及配制器具采样培养。结果纯化水制备工艺流程中的碳滤水、软化水及纯化水出口长满铜绿假单胞菌。结论本次0.1%苯扎溴铵消毒液污染是由纯化水制备系统污染未及时发现造成。     

Molecular epidemiology of Pseudomonas aeruginosa in an intensive care unit.

Genotyping was used to analyse Pseudomonas aeruginosa isolates from sink drains and 15 intubated patients as part of a 3-month prospective study of strain transmission in a medical-surgical intensive care unit. Ninety percent of all washbasin drains were persistently contaminated with several P. aeruginosa genotypes. In 60% (9/15) of the patients, P. aeruginosa colonization or infection was hospital-acquired: P. aeruginosa strains isolated from these patients were present in hospital sinks or in other patients before their admission. Since all patients were immobile, personnel were the probable route of transmission of P. aeruginosa in the hospital. The mechanism of strain transmission from sinks to hands during hand washing was investigated in a children''s hospital. When P. aeruginosa was present at densities of > 10(5)/c.f.u. per ml in sink drains, hand washing resulted in hand contamination with P. aeruginosa via aerosol generation in the majority of experiments or P. aeruginosa was detected using an air sampler above the washing basin. High P. aeruginosa cfu were present at 4.30 h in the eight sinks (5.4 x 10(5)-7.0 x 10(10) c.f.u./ml), whereas at 13.00 h P. aeruginosa c.f.u. were significantly lower (3.1 x 10(2)-8.0 x 10(5) c.f.u./ml). These data reveal that the danger of bacterial contamination of hands during hand washing is highest in the morning. The identified transmission routes demand more effective hygienic measures in hospital settings particularly concerning personnel hands and sink drains.     

ICU分离的铜绿假单胞菌血清分型及耐药性分析

目的确定重症监护室(ICU)铜绿假单胞菌流行菌株血清型别及其对抗菌药物的耐药情况,为研究铜绿假单胞菌感染的控制措施,合理应用抗菌药物提供依据。方法采用日本生研株式会社的铜绿假单胞菌血清分型试剂盒,对某院呼吸内科、神经内科、麻醉科ICU住院患者痰液及相关环境标本中分离的铜绿假单胞菌进行血清学分型及耐药性监测。结果3个ICU共检出铜绿假单胞菌88株,对其中80株进行了血清学分型,分型率90.91%;所占比率较大的血清型为:B型52.27%,G型22.73%,未分型菌9.09%。各型对10种抗菌药物的耐药种类数为:B与G型10种,未分型菌9种,D与E型8种,F型7种,I,M与K型<3种;铜绿假单胞菌对10种抗菌药物总的耐药率分别为:头孢曲松67.05%,阿洛西林61.36%,头孢吡肟44.32%,替卡西林/他唑巴坦54.55%,阿米卡星56.82%,头孢哌酮46.59%,左氧氟沙星54.55%,头孢哌酮/舒巴坦6.82%,亚胺培南55.68%,头孢他啶28.41%;B型菌的耐药率高于其他各型。结论该院ICU铜绿假单胞菌血清分型以B型为主;以多重耐药菌株多见;对头孢哌酮/舒巴坦和头孢他啶耐药率较低,此两种药可作为铜绿假单胞菌感染治疗的首选药物。     

探讨人工气道患者耐碳青霉烯类铜绿假单胞菌肺部感染的危险因素

目的 探讨人工气道患者耐碳青霉烯类铜绿假单胞菌肺部感染危险因素。方法 选择2018年7月—2020年7月人工气道患者218例作为对象,所有患者均使用耐碳青霉烯类抗菌药物,根据患者肺部是否感染铜绿假单胞菌分为感染组与非感染组。查阅两组病例资料,对上述可能的危险因素进行单因素及多因素Logistic分析;对感染的铜绿假单胞菌菌株进行耐药性分析。结果218例人工气道患者耐碳青霉烯类抗菌药物中铜绿假单胞菌菌肺部感染61例,感染率为27.98%。单因素结果表明：人工气道患者耐碳青霉烯类抗菌药物铜绿假单胞菌菌肺部感染率与性别、年龄、合并基础疾病、白细胞水平差异无统计学意义（P> 0.05）;与入院前卧床时间、急性生理学和慢性健康状况评价Ⅱ(acute physiology and chronic health evaluationⅡ,APACHE Ⅱ)评分、C反应蛋白（C reactive protein,CRP）、降钙素原（procalcitonin,PCT）、白蛋白、机械通气时间、抗菌药物使用差异有统计学意义（P <0.05）。61例铜绿假单胞菌菌肺部感染患者中分离出病原菌78株,...     

Pseudomonas aeruginosa outbreak in a haematology-oncology unit associated with contaminated surface cleaning equipment

An outbreak of six cases of hospital-acquired Pseudomonas aeruginosa infections (two pneumonia two septicaemia, two skin/wound infection) occurred between August and September 2000 in an adult haematology-oncology unit at a tertiary-care centre. During the outbreak, hospital-acquired infection (HAI) incidence density rates rose from 29.4 to 62.3 (P < 0.05) infections per 1000 days at risk (i.e., neutropenic days). A systematic outbreak management system was actioned in accordance with a German draft guideline. Multiple samples from the patients' environment were tested for the presence of P. aeruginosa. A total of 4.5% of samples from sanitary equipment and 20.0% of samples from surface cleaning equipment were found to be contaminated with P. aeruginosa. Genotypic analysis by pulsed-field gel electrophoresis showed different patterns for all (N = 6) of the patient isolates, however, two of the patient isolates were identical in comparison with environmental isolates from cleaning equipment (four samples) and sanitary equipment (one sample). Our investigation revealed that the cleaning staff had used cleaning solution instead of disinfectants for decontamination of the patients' environment. The outbreak was terminated after re-adoption of surface disinfection, application of sterile filters on taps and shower heads, chemical disinfection of the washbasin drains, and appointment of a hospital hygiene nurse to a previously unfilled position. After institution of the control measures, HAI incidence densities decreased to pre-outbreak level. This investigation emphasizes the need to carefully evaluate cleaning and disinfection practices for patient care, particularly in neutropenic patients.     

利用核酸恒温扩增技术检测下呼吸道感染病原菌的分布特征

目的 探讨环介导温扩增技术(Loop-mediate amplification,LAMP)检测呼吸道病原菌在临床中实际应用价值.方法 收集2018年3月-2019年4月徐州医科大学附属医院住院治疗的911例下呼吸道感染成人患者(＞18岁)的痰液标本,分别进行呼吸道病原菌核酸检测和痰培养,比较分析两种检测方法的检出结果...     

Contamination of small-volume medication nebulizers and its association with oropharyngeal colonization

The effect of the use of small-volume medication nebulizers on oropharyngeal colonization with potentially pathogenic Gram-negative bacilli was investigated in 95 patients with respiratory disease, of whom 54 used nebulizers and 41 were controls. Inhalation therapy had a significant effect on colonization, with a relative risk of more than four. Age over 60 years also showed a significant association with colonization. One-third of the nebulizers sampled were contaminated, 71% with Gram-negative bacilli. A direct route of contamination could be demonstrated in 28% of the patients. Medication nebulizers should be thoroughly cleaned after use and stored dry between patients.     

两种铜绿假单胞菌同源性分析方法比较

目的了解脂肪酸气相色谱分析方法能否应用于铜绿假单胞菌的同源性分析。方法收集某院2008年1—12月重症监护室住院患者痰标本分离的26株多重耐药铜绿假单胞菌,分别应用脉冲场凝胶电泳(PFGE)和脂肪酸气相色谱分析方法进行同源性分析,比较两组结果。结果 PFGE结果表明,26株菌有6个克隆;脂肪酸气相色谱分析显示,26株菌存在4个克隆,符合率仅26.92%(7/26)。结论脂肪酸气相色谱分析方法在菌株同源性判断的准确性上与PFGE分型有差距,其应用于铜绿假单胞菌的同源性分析仍需谨慎。