Failure of sterilization in a dental outpatient facility: Investigation,risk assessment,and management

In 2017, an incident of failed sterilization of dental instruments occurred at a large dental outpatient facility in Singapore. We aim to describe findings of the investigation of the sterilization breach incident, factors related to risk of viral transmission to the potentially affected patients, and the contact tracing process, patient management, and blood test results at a 6-month follow-up.A full assessment of the incident was immediately carried out. The factors related to risk of viral transmission due to affected instruments were analyzed using 3 keys points: breached step(s) and scale of the incident, prevalence of underlying bloodborne diseases and immunity in the Singapore population, health status of potential source patients, and type of dental procedure performed, and health status of affected patients and type of dental procedure received.Up to 72 affected instrument sets were used in 714 potentially affected patients who underwent noninvasive dental procedures. The investigation revealed that there was a lapse in the final step of steam sterilization, resulting in the use of incompletely sterilized items. The assessment determined that there was an extremely low risk of bloodborne virus transmission of diseases to the patients. At the 6-month follow-up, there were no infected/colonized cases found related to the incident.Lapses in the sterilization process for medical and dental instruments can happen, but a risk assessment approach is useful to manage similar incidents. Quick response and proper documentation of the sterilization process can prevent similar incidents.     

环维黄杨星D抗心房纤颤的作用及其电生理机制

环维黄杨星D(CVB-D)对CaCl₂-Ach诱发小鼠在体心房纤颤和乌头碱、哇巴因或肾上腺素所致豚鼠离体心房纤颤,有明显的剂量依赖性抑制作用,且作用强度与胺碘酮(Ami)相似。CVB-D0.3～100μmol·L^-1降低离体右心房自律性。对离体左心房,CVB-D0.3μmol·L^-1抑制肾上腺素引起的异常自律性,延长有效不应期和动作电位时程,降低兴奋性;高浓度时,可降低V_max,延长冲动传导时间。Ami0.3～30μmol·L^-1有相似的电生理作用,但对V_max无明显的影响。提示CVB-D可试用于心房纤颤的患者。     

三七中人参三醇甙对动物缺血性心律失常的影响

三七中人参三醇甙(简称PTS)能明显对抗大鼠结扎冠状动脉诱发的缺血性心律失常及再灌注性心律失常,并可使缺血再灌注引起的心肌梗塞范围明显缩小。对iv CaCl₂-Ach引起的小鼠房颤或房扑也有明显的保护作用。PTS还可明显延长小鼠在常压缺氧条件下的存活时间。     

＂Anti-HBc alone＂ in human immunodeficiency virus-positive and immuno-suppressed lymphoma patients

Hepatitis B virus （HBV） infection is endemic in various parts of the world. A proportion of patients have resolved prior exposure to HBV, as evidenced by the clearance of circulating hepatitis B surface antigen and the appearance of antibody to hepatitis B core antigen （anti-HBc）, which could produce protective antibody to hepatitis B surface antigen （anti-HBs）. With time, anti-HBs in some patients may become negative. Such patients are described as having occult HBV infection or ＂anti-HBc alone＂. In the context of immunodeficient patients, such as HIV patients or lymphoma patients undergoing immunosuppressive immunotherapy, the lack of protective anti-HBs may increase the risk of hepatitis B reactivation. Serum HBV DNA testing may be necessary in ＂anti-HBc alone＂ patients, to detect patients at a high risk of developing HBV infection allowing appropriate prophylactic management.     

The individual and combined influence of HIV and hepatitis C virus on dyslipidaemia in a high-risk Hispanic population

Objectives

To assess the effects of chronic hepatitis C (HCV) and HIV infection on dyslipidaemia in a Hispanic population at high risk of insulin resistance.

Methods

We compared serum lipids and C‐reactive protein (CRP) in 257 Hispanic adults including 47 HIV‐ mono‐infected, 43 HCV‐mono‐infected and 59 HIV/HCV‐co‐infected individuals as well as 108 healthy controls. We also assessed the effect of HCV on lipid alterations associated with antiretroviral therapy (ART), and the impact of HCV and HIV on the associations among insulin resistance, triglycerides and cholesterol.

Results

HCV infection was associated with lower total and low‐density lipoprotein (LDL) cholesterol, but not high‐density lipoprotein (HDL) cholesterol or triglycerides compared with healthy controls. HIV infection was associated with higher triglycerides and lower HDL, but not total or LDL cholesterol. HCV mitigated the elevation of triglycerides associated with ART. In healthy Hispanic adults, insulin resistance was significantly correlated with higher triglycerides, CRP and lower HDL. HIV infection nullified the association of insulin resistance with triglycerides and HDL, and the association of triglycerides with LDL. HCV infection nullified the association of insulin resistance with triglycerides, HDL and CRP.

Conclusions

HCV co‐infection alters the profile of HIV‐associated dyslipidaemia. The clinical significance of these findings for cardiovascular complications in HIV merits further study.     

Metabolic effects of antisickling amounts of nitrogen and nor-nitrogen mustard on rabbit and human erythrocytes

Nitrogen mustard (NH2) and Nor-nitrogen mustard (Nor-HN2) both inhibit the polymerization of deoxyhemoglobin S in solution and in intact erythrocytes. Metabolic studies were undertaken to determine the feasability of an extracorporeal treatment with these or related agents. Glucose utilization, hexose monophosphate shunt activity, methemoglobin reduction, and incubation with acetylphenylhydrazine for Heinz body formation were performed, as well as specific assays for hexokinase, pyruvate kinase, glucose-6-phosphate dehydrogenase, glutathione reductase, ATP, reduced glutathione (GSH), and survival of autologous mustard-treated cells in rabbits. HN2 was found to enter red cells rapidly and bind to intracellular contents. Metabolic studies revealed no significant inhibition or alteration of function by Nor-HN2 at 10 mg/ml of whole blood. Rabbit red cell survival was also normal. HN2, however, inhibited glutathione reductase and blocked the free sulfhydryl group of GSH by forming serveral addition products of alkylated GSH. Heinz body test with acetylphenylhydrazine became positive in HN2-treated cells, and rabbit red cell survival was shortened considerably in the concentration range used to inhibit sickling. Ascorbic acid stimulation of the hexose shunt pathway was inhibited by HN2, but methylene blue stimulation remained unaffected. 14-C-HN2 remains bound to red cells in vivo, and the disappearance of radioactivity is similar to that found with 14-C-DFP (disopropylfluorophosphate). Oxygen affinity of both HN2 and Nor-HN2 treated human red cells remains virtually the same as that found in control samples. It is concluded that Nor-HN2 may be a suitable agent for an extracorporeal therapy, and that each mustard needs to be evaluated individually for its antisickling effects and its suitability for extracorporeal use.     

Constitutive in vivo cytokine and hematopoietic growth factor gene expression in the bone marrow and peripheral blood of healthy individuals

We investigated hematopoietic growth factor (HGF) and cytokine gene expression in the bone marrow (BM) and peripheral blood (PB) of healthy individuals as a starting point for delineating the physiologic role of cytokines in steady state hematopoiesis. BM biopsy specimens and PB samples from 7 healthy individuals were analyzed by polymerase chain reaction amplification of reverse-transcribed RNA using gene-specific primer sets. Consistent gene expression in the BM of all 7 individuals was detected for macrophage colony-stimulating factor (CSF), stem cell factor, interleukin-6 (IL-6), IL-7, erythroid-potentiating factor, erythroid-differentiating factor, and insulinlike growth factor 1, all cytokines with reported direct stimulatory effects on in vitro hematopoiesis. Of these, erythroid-potentiating factor and erythroid- differentiating factor appeared to be the only stimulating factors that were also expressed in the PB. Among the cytokines with inhibitory effects on in vitro hematopoiesis IL-4, tumor necrosis factor-alpha (TNF-alpha), TNF-beta, transforming growth factor-beta, and macrophage inflammatory protein-1 alpha were expressed in the BM of the 7 individuals. Except for TNF-alpha, the latter cytokines were also expressed in the PB. Consistent expression in the BM and PB of all tested individuals was also observed for IL-1 beta, IL-1 receptor antagonist, and IL-1 beta converting enzyme, which are all members of the IL-1 family with a possible indirect effect on hematopoiesis. Remarkably, no expression of granulocyte CSF, granulocyte-macrophage CSF, and IL-3 was found in the BM or PB of all investigated individuals (n = 15). This was also the case for IL-1 alpha, IL-2, IL-5, IL-9, IL- 12, IL-13, leukemia-inhibiting factor, interferon-gamma, and inhibin. Weak IL-8 and IL-10 expression was found in the BM and/or PB of a minority of investigated individuals. These findings provide insight into which cytokines or HGFs potentially are involved in the autocrine or paracrine regulation of in vivo steady state hematopoiesis. The absence of expression of granulocyte CSF, granulocyte-macrophage CSF, and IL-3 in the BM of healthy individuals implicates that it is highly unlikely that these HGFs are involved in the autocrine or paracrine regulation of constitutive hematopoiesis.     

Prospective evaluation of the clinical usefulness of an antigen- specific assay (MAIPA) in idiopathic thrombocytopenic purpura and other immune thrombocytopenias

The diagnosis of idiopathic immune thrombocytopenia remains a clinical diagnosis based on the exclusion of other causes of immune and nonimmune thrombocytopenia. Measurement of platelet-associated Ig (PAIg), while sensitive, is nonspecific for the diagnosis of immune thrombocytopenia. Published experience of antigen capture assays (including monoclonal antibody immobilization of platelet antigens or MAIPA) suggest a high sensitivity and specificity (70% to 80%) in selected groups of patients. In a prospective evaluation of 158 patients with thrombocytopenia from all causes, we report a sensitivity of 51% and specificity of 80% for direct MAIPA assays. MAIPA was considerably better in discriminating immune from nonimmune thrombocytopenia than two assays of PAIgG. Antiplatelet antibodies detected by MAIPA were more frequently directed against the glycoprotein (GP) IIb/IIIa than the GP Ib/IX complex. Our experience suggests that MAIPA assays are useful in the laboratory assessment of thrombocytopenia, should be performed before therapy, and that some patients with 'nonimmune' thrombocytopenia may have genuine antiplatelet antibodies.     

A 5 - year surveillance of wound infections at a rural tertiary hospital in Nigeria

Background

Wound infections are associated with increased morbidity and mortality.

Objectives

To determine the prevalence, aetiology and susceptibility profile of bacterial agents of wound infection among in- and- out patients at a rural tertiary hospital in Nigeria, within a 5 year period.

Methods

Wound swabs collected from 156 out-patients and 353 in-patients were, cultured and microbial isolates identified using standard methods. Antibiotic susceptibility testing was done on bacterial isolates.

Results

The prevalence of wound infection in 2006, 2007, 2008, 2009 and 2010 was 71.4%, 76.2%, 74.5%, 61.5%, and 67.0% respectively. The overall prevalence of wound infection was 70.1%. In all the years studied, out-patients had a higher prevalence of wound infection, but this was significant in 2007, 2009, and 2010 only. Staphylococcus aureus was the most prevalent pathogen in both in- and out - patients with the exception of 2009 where both Staphylococcus aureus and Pseudomonas aeruginosa had the same prevalence (24.4%) among in - patients. The flouroquinolones were the most potent antimicrobial agents against bacterial isolates from both in - and out -patients.

Conclusion

Staphylococcus aureus was the most predominant etiologic agent of wound infection among in and out patients. A generally higher resistance pattern was observed among nosocomial bacterial pathogens. Prudent use of antibiotics is recommended.