Healthcare equipment as a source of nosocomial infection: a systematic review

Nosocomial infections (NIs) result in significant financial and individual costs, with large numbers of patients acquiring infections annually. Healthcare equipment has been identified as a likely source of these infections, and research indicates that up to one-third of all NIs may be prevented by adequate cleaning of equipment. Thus, this systematic review aimed to determine levels of contamination on healthcare equipment, to identify viable cleaning protocols and to establish the methodological quality of current evidence. Published and unpublished studies from January 1972 to December 2004 were identified in eight major databases. Methodological quality was evaluated using the hierarchy of evidence and a quantitative critical appraisal tool. Data were extracted and analysed using five major outcome measures. Fifty studies were identified investigating a range of healthcare equipment, of which 23 were included in the review. Methodological quality ranged from 6.5 to 9.5 out of 14 for observational studies and from 6.5 to 9.5 out of 15 for repeated measures studies. The included studies reported that 86.8% of all sampled equipment was contaminated, with 70% alcohol reducing the levels of contamination on equipment by 82.1%. Healthcare equipment is a significant source of NI. High levels of contamination are present on a wide range of healthcare equipment. However, the majority of contamination and hence any risk of acquiring a NI can be reduced substantially by regular cleaning of equipment with 70% alcohol. Further research is required into the role of community healthcare equipment in NI.     

Nucleotide oligomerization domain 1 is a dominant pathway for NOS2 induction in vascular smooth muscle cells: comparison with Toll-like receptor 4 responses in macrophages

Background and purpose:

Gram-negative bacteria contain ligands for Toll-like receptor (TLR) 4 and nucleotide oligomerization domain (NOD) 1 receptors. Lipopolysaccharide (LPS) activates TLR4, while peptidoglycan products activate NOD1. Activation of NOD1 by the specific agonist FK565 results in a profound vascular dysfunction and experimental shock in vivo.

Experimental approach:

Here, we have analysed a number of pharmacological inhibitors to characterize the role of key signalling pathways in the induction of NOS2 following TLR4 or NOD1 activation.

Key results:

Vascular smooth muscle (VSM) cells expressed NOD1 mRNA and protein, and, after challenge with Escherichia coli or FK565, NOS2 protein and activity were induced. Macrophages had negligible levels of NOD1 and were unaffected by FK565, but responded to E. coli and LPS by releasing increased NO and expression of NOS2 protein. Classic pharmacological inhibitors for NF-κB (SC-514) and mitogen-activated protein kinase (SB203580, PD98059) signalling pathways inhibited responses in both cell types regardless of agonist. While TLR4-mediated responses in macrophages were specifically inhibited by the pan-caspase inhibitor z-VAD-fmk and the PKC inhibitor Gö6976, NOD1-mediated responses in VSM cells were inhibited by the Rip2 inhibitor PP2.

Conclusions and implications:

Our findings suggest a selective role for NOD1 in VSM cells, and highlight NOD1 as a potential novel therapeutic target for the treatment of vascular inflammation.     

Assessing the outcome of the management of diabetic foot ulcers using ulcer-related and person-related measures

OBJECTIVE: The purpose of this study was to compare different outcome measures in the audit of management of diabetic foot ulcers RESEARCH DESIGN AND METHODS: Data collected prospectively in a consecutive cohort of patients referred to a specialist multidisciplinary foot care clinic between 1 January 2000 and 31 December 2003 were analyzed. A single index ulcer was selected for each patient and classified according to both the Size (Area and Depth), Sepsis, Arteriopathy, and Denervation [S(AD)SAD] and University of Texas (UT) systems. Ulcer-related outcomes (healing, resolution by ipsilateral amputation or by death, and persisting unhealed) were determined at 6 and 12 months and compared with patient-related outcomes (survival, any amputation, and being free from any ulcer) at 12 months. RESULTS: In 449 patients (63.7% male, mean age 66.7 +/- 13.2 years), 352 (78.4%) ulcers were superficial [S(AD)SAD/UT grade 1] and 134 of these (38.1% of 352) were neither ischemic nor infected. A total of 183 (40.8% of 449) ulcers were clinically infected, and peripheral arterial disease was present in 216 patients (48.1%). Seventeen patients (3.8%) were lost to follow-up and were excluded from analysis. Of the ulcers, 247 (55.0% of 449) and 295 (65.7%) healed without amputation by 6 and 12 months, respectively. Median (range) time to healing was 78 (7-364) days. Of all index ulcers, 5.8 and 8.0% were resolved by amputation, and 6.2 and 10.9% by death by the same time points; 27.8 and 11.6% persisted unhealed. In contrast, patient-related outcomes revealed that of 449 patients only 202 (45.0%) were alive, without amputation, and ulcer free at 12 months. This group had had 272 (1-358) days without any ulcer. A total of 48 (10.7%) patients had undergone some form of amputation, and 75 (16.7%) had died. CONCLUSIONS: These data illustrate the extent to which ulcer-related outcomes may underestimate the true morbidity and mortality associated with diabetic foot disease. It is suggested that when attempts are made to compare the effectiveness of management in different centers, greater emphasis should be placed on patient-related outcome measures.     

Prevalence of Murine Helicobacter spp. Infection Is Reduced by Restocking Research Colonies with Helicobacter-Free Mice

Most academic research colonies of mice are endemically infected with enterohepatic Helicobacter spp. (EHS). We evaluated EHS prevalence in surveillance mice before and after a 10-y period of requiring that imported mice be free of EHS by embryo transfer rederivation or purchase from approved vendors. In 2009, composite fecal samples from CD1 surveillance mice representing colony health in 57 rooms located in 6 facilities were evaluated for EHS infection by using PCR assays. Fecal samples were screened with primers designed to detect all known EHS, and positive samples were further assayed by using primers specific for H. hepaticus, H. bilis, H. rodentium, and H. typhlonicus. Most EHS were detected in surveillance mice within the first month of dirty bedding exposure, with prevalence ranging from 0% to 64% as monoinfections or, more commonly, infections with multiple EHS. Compared with 1999 prevalence data, EHS remained endemic in colonies importing the lowest number of EHS-free mice. EHS were absent or the prevalence was greatly reduced in colonies receiving the highest percentage of EHS-free mice. This study demonstrates that the management decision to require exclusive importation of EHS-free mice reduced EHS prevalence on an institutional scale without intensive labor and expense associated with other techniques or interference with research objectives.Abbreviation: EHS, enterohepatic Helicobacter spp.; ET, embryo transfer; Hb, H. bilis; Hh, H. hepaticus; Hm, H. mastomyrinus; Hr, H. rodentium; Ht, H. typhlonicusEnterohepatic Helicobacter spp. (EHS) infections are endemic in the majority of research mouse colonies. In 2007, 84% of mice shipped from academic institutions worldwide for embryo transfer (ET) rederivation at our institution were PCR-positive for EHS. H. hepaticus (Hh) was detected in 64% of the mouse shipments either as a monoinfection or in combination with other EHS including H. bilis (Hb), H. rodentium (Hr), H. typhlonicus (Ht), and H. mastomyrinus (Hm).³⁰ Although EHS generally cause subclinical infection in immunocompetent mice, opportunistic infections have the potential to confound experimental data in mouse models.^9,17,34 Importantly, chronic EHS infection in immunodeficient and select inbred strains of mice can induce liver¹⁰ and lower bowel carcinoma,¹³ typhlocolitis, and rectal prolapse,^16,21,28 and reduce reproductive performance.²⁵ In addition, EHS-induced inflammatory responses may alter host immune responses to unrelated experimental infections (for example, promoting elevated systemic IFNγ responses).^3,20Key challenges to eradication of EHS from rodent colonies are determining infection status, eliminating endemic infections, and instituting management practices that prevent reinfection. EHS are disseminated through fecal–oral transmission within a colony and are transmissible to surveillance mice through dirty-bedding exposure.^1,19,24,32 For routine surveillance, PCR assay of feces or cecal mucosal scrapings for genus-specific Helicobacter 16S rRNA genes is the most efficient means of detecting EHS infection, with speciation (if desired) of positive results by culture, restriction fragment length polymorphism analysis, species-specific PCR, or sequence analysis.³⁴ In 1999, as determined by species-specific PCR assays of cecal scrapings from 59 surveillance mice exposed to dirty bedding from colony mice in 26 rooms representing 4 mouse facilities, EHS were endemic on our campus, with prevalence in surveillance mice of 41% for Hh, 82% for Hr, and 6% for Hb.³² Husbandry practices used to minimize cage-to-cage transmission of EHS included microisolation caging, sanitized forceps to transfer mice, and a cage change order from known Helicobacter-free mice to mice of unknown or known EHS infection status (that is, clean to dirty traffic flow of personnel and equipment).³² Although EHS eradication potentially could be accomplished campus-wide by using labor-intensive antibiotics^7,15 and cross-fostering,^4,29,31 we hypothesized that a more cost-effective approach, without confounding experimental data, would be to restrict importation of mice to EHS-free sources. Vendors were screened to establish that production colonies were SPF for EHS, and a new requirement was instituted for embryo transfer (ET) rederivation of mice obtained from random sources, typically other academic institutions, replacing traditional quarantine practices. This study used PCR data from 1999 and 2009 to evaluate the success of this approach, which was defined as a marked decrease in the prevalence of EHS infection over time.     

Catheter ablation of accessory pathways, atrioventricular nodal reentrant tachycardia, and the atrioventricular junction: final results of a prospective, multicenter clinical trial. The Atakr Multicenter Investigators Group

BACKGROUND: The purpose of this study was to evaluate the safety and efficacy of a temperature-controlled radiofrequency catheter ablation system. METHODS AND RESULTS: The patient population included 1050 patients who had undergone ablation of atrioventricular nodal reentrant tachycardia (AVNRT), an accessory pathway (AP), or the atrioventricular junction (AVJ). Ablation was successful in 996 patients. The probability of success was highest among patients who had undergone ablation of the AVJ, lowest in patients who had undergone ablation of an AP, and in between for patients who had undergone ablation of AVNRT. A major complication occurred in 32 patients. Four variables predicted ablation success (AVJ, AVNRT, or left free wall AP ablation and an experienced center). Four factors predicted arrhythmia recurrence (right free wall, posteroseptal, septal, and multiple APs). Two variables predicted development of a complication (structural heart disease and the presence of multiple targets), and 3 variables predicted an increased risk of death (heart disease, lower ejection fraction, and AVJ ablation). CONCLUSIONS: These findings may serve as a guide to clinicians considering therapeutic options in patients who are candidates for ablation.     

中药材龟板和鳖甲中DNA的提取与扩增

中药材龟板和鳖甲中ＤＮＡ的提取与扩增王亚明，周开亚，吴平，徐珞珊（南京师范大学生物系，南京２１００９７；中国药科大学生药学研究室，南京２１０００９）龟鳖类药材在我国使用历史悠久，具补阴益气的功效。《中国药典》（１９９０年版）规定龟甲（龟板）的原动物为...