Hospital environment and invasive aspergillosis in patients with hematologic malignancy.

BACKGROUND: To determine whether there is a correlation between sources of Aspergillus spores in a high-efficiency particulate air (HEPA)-filtered environment and nosocomial invasive aspergillosis (IA), we performed a detailed environmental assessment and case review. METHODS: From April to October 2004, 626 bioaerosol samples, 1,257 surface samples, and 607 water samples were obtained from 74 HEPA-filtered air hospital rooms occupied by 458 patients with hematologic malignancies. Samples were collected prospectively from the room before and after cleaning within 1 hour of patient admission or discharge. Aspergillus spp was isolated from 21 surface samples and 46 bioaerosol samples. Interestingly, Aspergillus spp was not isolated from any water samples. RESULTS: Aspergillus spp was isolated from 21 surface samples and 46 bioaerosol samples. Interestingly, Aspergillus spp were not isolated from any water samples. The majority (90%) of the positive bioaerosol samples had ≤ 10 colony-forming units of Aspergillus/m3 of air. Only 2 patients developed nosocomial IA. No correlations were found between Aspergillus species isolated from the hospital rooms and those causing IA. CONCLUSION: The risk of hematologic malignancy patients acquiring nosocomial aspergillosis from water or HEPA-filtered air is very low.

Clinical effectiveness and risk of emerging resistance associated with prolonged use of antibiotic-impregnated catheters: more than 0.5 million catheter days and 7 years of clinical experience.

OBJECTIVES: Catheters coated with minocycline and rifampin are proven to decrease the rates of central line-associated bloodstream infection; however, it is unclear whether success occurs independent of other infection control precautions. We evaluated the effect of catheters coated with minocycline and rifampin with and without other infection control precautions on our rates of central line-associated bloodstream infection in critically ill patients and on antibiotic resistance throughout the hospital and in the intensive care unit. DESIGN: Retrospective clinical cohort study conducted during 1999-2006 with an observational laboratory component. SETTING: A tertiary university-based cancer center. PATIENTS: All 8009 patients admitted to the medical intensive care unit were subjects for the surveillance of central line-associated bloodstream infection. All Staphylococcus aureus and coagulase-negative staphylococci clinical isolates cultured at our institution during the same period were subjects for laboratory testing. INTERVENTIONS: Using catheters coated with minocycline and rifampin and implementing infection control precautions. MEASUREMENTS AND MAIN RESULTS: Incidence of central line-associated bloodstream infection in the medical intensive care unit. Change in resistance to tetracycline and rifampin in clinically relevant staphylococcal isolates in the intensive care unit and hospitalwide. During the study period, 9200 catheters coated with minocycline and rifampin were used hospitalwide over a total of 511,520 catheter days. The incidence of central line-associated bloodstream infection per 1000 patient days in the medical intensive care unit significantly and gradually decreased from 8.3 in 1998 to 1.2 in 2006 (p ≤ .001). The resistance of S. aureus and coagulase negative staphylococci clinical isolates to tetracycline or rifampin in the intensive care unit and on a hospitalwide level remained stable or decreased significantly during the same period. CONCLUSIONS: Catheters coated with minocycline and rifampin significantly decreased the incidence of central line-associated bloodstream infection in the medical intensive care unit in a manner that was independent and complementary to the infection control precautions. Although this study strongly suggests an association between catheters coated with minocycline and rifampin use and a decrease in central line-associated bloodstream infection, because of multiple other concurrent interventions, the results should be interpreted cautiously until a prospective study is conducted. Furthermore, long-term use of these devices is not associated with increased resistance of staphylococcal isolates to tetracycline and rifampin in the intensive care unit or throughout the hospital.

Risk of bioaerosol contamination with Aspergillus species before and after cleaning in rooms filtered with high-efficiency particulate air filters that house patients with hematologic malignancy.

OBJECTIVE: To examine the impact of cleaning and directional airflow on environmental contamination with Aspergillus species in hospital rooms filtered with high-efficiency particulate air (HEPA) filters that house patients with hematologic malignancy. DESIGN: Detailed environmental assessment. SETTING: A 475-bed tertiary cancer center in the southern United States. METHODS: From April to October 2004, 1,258 surface samples and 627 bioaerosol samples were obtained from 74 HEPA-filtered rooms (in addition, 88 outdoor bioaerosol samples were obtained). Samples were collected from rooms cleaned within 1 hour after patient discharge and from rooms before cleaning. Positive and negative airflows were evaluated using air-current tubes at entrances to patient rooms. RESULTS: Of 1,258 surface samples, 3.3% were positive for Aspergillus species. Univariate analysis showed no relationship between cleaning status and occurrence of Aspergillus species. Of 627 bioaerosol samples, 7.3% were positive for Aspergillus species. Multiple logistic analysis revealed independently significant associations with detection of Aspergillus species. Cleaned rooms positive for Aspergillus species had a higher geometric mean density of colonies than that of rooms sampled before cleaning (18.9 vs 5.5 colony-forming units [cfu] per cubic meter; P=.0047). Rooms with positive airflow had a detection rate for bioaerosol samples equivalent to that of rooms with negative airflow (7.3% vs 7.8%; P=.8). There was no significant difference in the density of Aspergillus species between rooms with negative airflow and rooms with positive airflow (12.5 vs 8.4 cfu/m(3); P=.33). CONCLUSIONS: Concentration of bioaerosol contamination with Aspergillus species was increased in rooms sampled 1 hour after cleaning compared with rooms sampled before cleaning, suggesting a possible correlation between re-entrained bioaerosols (ie, those suspended by activity in the room) after cleaning and the risk of nosocomial invasive aspergillosis.

Risk factors for infections with multidrug-resistant Pseudomonas aeruginosa in patients with cancer.

BACKGROUND: Pseudomonas aeruginosa is responsible for a wide range of infections. In immunocompromised patients with cancer, the emergence of multidrug resistant P. aeruginosa may have grave consequences. METHODS: Patients with cancer who were infected with multidrug-resistant P. aeruginosa with polyclonal DNA restriction patterns were used as the case group. Two control groups were used: one group of cancer patients who were infected with multidrug-susceptible P. aeruginosa and another group of cancer patients who had the same underlying disease and the same intensive care unit exposure as patients in the case group but who were not infected or colonized by P. aeruginosa. RESULTS: Risk factors that were associated significantly with multidrug-resistant P. aeruginosa infection were the use of carbapenem for > or = 7 days, a history of P. aeruginosa infection during the preceding year, and a history of chronic obstructive pulmonary disease (P < 0.01). CONCLUSIONS: Carbapenems may need to be used more judiciously as first-line empirical therapy for cancer patients with prior pseudomonal infection or chronic obstructive pulmonary disease who require hospitalization, and alternative, antipseudomonal antibiotic regimens may need to be considered, especially in this patient population.

Impact of surveillance for vancomycin-resistant enterococci on controlling a bloodstream outbreak among patients with hematologic malignancy.

OBJECTIVE: To determine the impact of stool surveillance cultures of critically ill patients on controlling vancomycin-resistant enterococci (VRE) outbreak bacteremia. DESIGN: Stool surveillance cultures were performed on patients who had hematologic malignancy or were critically ill at the time of hospital admission to identify those colonized with VRE. Hence, contact isolation was initiated. SETTING: A tertiary-care cancer center with a high prevalence of VRE. PARTICIPANTS: All patients with hematologic malignancy who were admitted to the hospital as well as all of those admitted to the intensive care unit were eligible. RESULTS: Active stool surveillance cultures performed between 1997 and 2001 decreased the incidence density of VRE bacteremias eightfold while vancomycin use remained constant. In fiscal year (FY) 1997 and FY 1998, there were five and three VRE outbreak bacteremias, respectively. The outbreak clones were responsible for infection in 69% of those patients with VRE bacteremia. However, the stool surveillance program resulted in the complete control of VRE bacteremia by FY 1999 until the end of the study. CONCLUSION: Despite the steady use of vancomycin, the active surveillance program among high-risk patients with hematologic malignancy and those who were critically ill resulted in the complete control of VRE outbreak bacteremia at our institution.

Antibiotic-impregnated catheters associated with significant decrease in nosocomial and multidrug-resistant bacteremias in critically ill patients.

OBJECTIVE: To evaluate the impact of using central venous catheters (CVCs) impregnated with the combination of minocycline and rifampin on nosocomial bloodstream infections (BSIs), morbidity, and mortality in cancer patients in the ICU. DESIGN: Prospective surveillance study consisting of the following two time periods: September 1997 through August 1998 (ie, fiscal year [FY] 1998); and from September 1998 through August 1999 (ie, FY 1999). SETTING: ICUs of a tertiary care hospital in Houston, TX. PATIENTS: Cancer patients in the medical ICU (MICU) and surgical ICU (SICU). INTERVENTIONS: ICUs started using CVCs impregnated with the minocycline-rifampin combination at the beginning of FY 1999. MEASUREMENTS AND MAIN RESULTS: The rates of nosocomial BSIs and other patients' characteristics were compared for the two study periods to determine the impact of using the impregnated catheters in the ICU. Patients' characteristics, including antibiotic use, were comparable for the two study periods in both the MICU and the SICU. The rate of nosocomial BSIs in the MICU unit decreased from 8.3 to 3.5 per 1,000 patient-days (p < 0.01), and decreased in the SICU from 4.8 to 1.3 per 1,000 patient-days (p < 0.01) in FY 1999. Nosocomial vancomycin-resistant enterococcus (VRE) bacteremia also decreased significantly (p = 0.004). Length of stay in the MICU and SICU significantly decreased in FY 1999 (p < 0.01 and p = 0.03, respectively). The duration of hospitalization decreased for MICU and SICU patients (p = 0.06 and p < 0.01, respectively). The rate of catheter-related infections decreased from 3.1 to 0.7 per 1,000 patient-days in FY 1999 (p = 0.02). The decrease in infections resulted in net savings of at least $1,450,000 for FY 1999. CONCLUSIONS: The use of antibiotic-impregnated CVCs in the MICU and SICU was associated with a significant decrease in nosocomial BSIs, including VRE bacteremia, catheter-related infections, and lengths of hospital and ICU stays.