An intensive care unit outbreak with multi-drug-resistant Pseudomonas aeruginosa - spotlight on sinks.

BACKGROUND: Pseudomonas aeruginosa and other Gram-negative bacteria have the ability to persist in moist environments in healthcare settings, but their spread from these areas can result in outbreaks of healthcare-associated infections. METHODS: This study reports the investigation and containment of a multi-drug-resistant P. aeruginosa outbreak in three intensive care units of a Swiss university hospital. In total, 255 patients and 276 environmental samples were screened for the multi-drug-resistant P. aeruginosa outbreak strain. The environmental sampling and molecular characterization of patient and environmental strains, and control strategies implemented, including waterless patient care, are described. RESULTS: Between March and November 2019, the outbreak affected 29 patients. Environmental sampling detected the outbreak strain in nine samples of sink siphons of three different intensive care units with a common water sewage system, and on one gastroscope. Three weeks after replacement of the sink siphons, the outbreak strain re-grew in siphon-derived samples and newly affected patients were identified. The outbreak ceased after removal of all sinks in the proximity of patients and in medication preparation areas, and minimization of tap water use. Multi-locus sequence typing indicated clonality (sequence type 316) in 28/29 patient isolates and all 10 environmental samples. CONCLUSIONS: Sink removal combined with the introduction of waterless patient care terminated the multi-drug-resistant P. aeruginosa outbreak. Sinks in intensive care units may pose a risk for point source outbreaks with P. aeruginosa and other bacteria persisting in moist environments.

Synovial C-reactive protein features high negative predictive value but is not useful as a single diagnostic parameter in suspected periprosthetic joint infection (PJI).

OBJECTIVES: Synovial fluid C-reactive protein (syCRP) has been recently described as a new biomarker in preoperative diagnostics to identify periprosthetic joint infections (PJI). The aim of this study was to evaluate syCRP in a large cohort of patients with suspected PJI and to calculate the optimal cut-off to diagnose PJI. METHODS: Between September 2015 and June 2017, we prospectively included patients with suspected PJI, in which syCRP was additionally measured along with routine preoperative diagnostic serum and synovial biomarkers. We analysed the sensitivity and specificity of syCRP using receiver operating characteristic curves. RESULTS: We included 192 cases (hip n = 80, knee n = 91, shoulder n = 21) with a final diagnosis of PJI in 26 cases (14.0%). Combined for all joints, the syCRP values were significantly higher in the PJI group than in the no PJI group (median: 13.8 vs. 0 mg/l; p < 0.001). The optimal cut-off (Youden Index: 0.71) for the PJI diagnosis combined for all joints was at a syCRP value of 2.9 mg/l with a sensitivity of 88%, a specificity of 82%, and a negative predictive value of 98%. CONCLUSIONS: SyCRP features high negative predictive value but is not useful as a single diagnostic parameter in suspected periprosthetic joint infection (PJI).

ESCMID white paper: a guide on ESCMID guidance documents.

BACKGROUND AND AIM: The European Society of Clinical Microbiology and Infectious Diseases (ESCMID) aims to further develop its role in international medical and scientific guidance in the field of Clinical Microbiology and Infectious Diseases, where many types of guidance documents exist. The ESCMID Executive Committee and the Clinical Microbiology and Infection (CMI) editorial board wish to clarify the terminology and format to be used in ESCMID guidance documents submitted for publication in CMI, and to highlight the principles behind ESCMID guidance documents. TYPES OF GUIDANCE DOCUMENTS: There are five types of ESCMID guidance documents: White Papers, Clinical Practice Guidelines, Consensus Statements, State-of-the-Science Statements, and Position Papers. They differ in scope, methods of development, drafting group composition and preferred publication format. Guidance documents can be proposed, developed and published by ESCMID Study Groups, Committees and individual members; often, other scientific societies are involved. The full disclosure of potential conflicts of interest of all drafting group members is a requirement. FINAL REMARKS: Guidance documents constitute a common cultural and scientific background to people in the same and related professions. Also, they are an important educational and training tool. Developing a guidance document is a scientific endeavour, where a sound and transparent development process is needed, requiring multidisciplinary and personal skills.

Human polyspecific immunoglobulin attenuates group A streptococcal virulence factor activity and reduces disease severity in a murine necrotizing fasciitis model.

OBJECTIVES: Streptococcus pyogenes causes life-threatening invasive infections including necrotizing fasciitis (NF). Current treatment guidelines recommend the use of a cell-wall-active antibiotic combined with a protein synthesis inhibitor and surgical debridement in NF patients. Adjunctive therapy with intravenous immunoglobulin (IVIG) has been proposed for superantigen-associated streptococcal toxic shock syndrome. So far, benefits of IVIG treatment remain unclear and prospective clinical studies are scarce. Thus, we aimed to assess the effects of IVIG on virulence factor activity in vitro, ex vivo in patients and in vivo in a NF mouse model. METHODS: We investigated the effect of IVIG on the activity of the virulence factors streptolysin O (SLO), streptodornase 1 (Sda1), S. pyogenes cell envelope protease and streptococcal pyrogenic exotoxin B in vitro and ex vivo in patient sera. Additionally, we assessed the influence of IVIG on the clinical outcome in a murine NF model. RESULTS: In vitro, IVIG inhibited various streptococcal virulence factors. Further, IVIG treatment of group A Streptococcus-infected mice led to a reduced skin lesion size (median (interquartile range) day 3 intraperitoneal administration: 12 mm2 (9-14.5) vs. 4 mm2 (0.8-10.5), subcutaneous: 10.3 mm2 (6.9-18.6) vs. 0.5 mm2 (0.1-6.8)) and lower SLO activity. After treatment with IVIG, patient sera showed an elevated titre of specific SLO (7/9) and Sda1 (5/9) antibodies, reducing SLO and Sda1 activity. CONCLUSIONS: The clear reduction in disease severity in IVIG-treated mice and inhibition of virulence factor activity in mouse and human sera suggest that IVIG may be beneficial in invasive group A Streptococcus infections such as NF in addition to streptococcal toxic shock syndrome.

Inflammatory disorders mimicking periprosthetic joint infections may result in false-positive α-defensin.

OBJECTIVES: The antimicrobial peptide α-defensin has recently been introduced as a potential 'single' biomarker with a high sensitivity and specificity for the preoperative diagnosis of periprosthetic joint infections (PJIs). However, most studies assessed the benefits of the test with exclusion of patients with rheumatic diseases. We aimed to evaluate the α-defensin test in a cohort study without exclusion of people with inflammatory diseases. METHODS: Between June 2016 and June 2017, we prospectively included cases with a suspected PJI and an available lateral flow test α-defensin (Synovasure®) in synovial fluid. We compared the test result to the diagnostic criteria for PJIs published by an International Consensus Group in 2013. RESULTS: We included 109 cases (49 hips, 60 knees) in which preoperative α-defensin tests had been performed. Among these, 20 PJIs (16 hips, four knees) were diagnosed. Preoperative α-defensin tests were positive in 25 cases (22.9%) with a test sensitivity and specificity of 90% and 92.1% (95% CI 68.3%-98.8% and 84.5%-96.8%, respectively), and a high negative predictive value of 97.6% (95% CI 91.7%-99.4%). We interpreted seven α-defensin tests as false positive, mainly in cases with inflammatory rheumatic diseases, including crystal deposition diseases. CONCLUSIONS: A negative synovial α-defensin test can reliably rule out a PJI. However, the test can be false positive in conjunction with an underlying non-infectious inflammatory disease. We therefore propose to use the α-defensin test only in combination with Musculoskeletal Infection Society criteria and assessment for crystals in synovial aspirates.

Chloroquine enhances the antimycobacterial activity of isoniazid and pyrazinamide by reversing inflammation-induced macrophage efflux.

Mycobacterium tuberculosis (MTB) is notorious for persisting within host macrophages. Efflux pumps decrease intracellular drug levels, thus fostering persistence of MTB during therapy. Isoniazid (INH) and pyrazinamide (PZA) are substrates of the efflux pump breast cancer resistance protein-1 (BCRP-1), which is inhibited by chloroquine (CQ). In this study, BCRP-1 was found to be expressed on macrophages of human origin and on foamy giant cells at the site of MTB infection. In the current in vitro study, interferon-gamma (IFNγ) increased the expression of BCRP-1 in macrophages derived from the human monocytic leukaemia cell line THP-1. Using a BCRP-1-specific fluorescent dye and radioactively labelled INH, it was demonstrated that efflux from macrophages increased upon activation with IFNγ. CQ was able to inhibit active efflux and augmented the intracellular concentrations both of INH and the dye. In agreement, CQ and specific inhibition of BCRP-1 increased the antimycobacterial activity of INH against intracellular MTB. Although PZA behaved differently, CQ had comparable advantageous effects on the intracellular pharmacokinetics and activity of PZA. The adjunctive effects of CQ on intracellular killing of MTB were measurable at concentrations achievable in humans at approved therapeutic doses. Therefore, CQ, a widely used and worldwide available drug, may potentiate the efficacy of standard MTB therapy against bacteria in the intracellular compartment.

Spacecraft bacterium, Paenibacillus pasadenensis, causing wound infection in humans.

In a patient with mediastinitis after cardiac surgery Paenibacillus pasadenensis was detected in his sternal wound. Paenibacilli are gram-positive, aerobic, bacteria related to bacilli. Until recently these organisms were not known to cause human disease. A few cases of human infection caused by another member of this genus, P alvei, have been reported. The authors describe the first infection with P pasadenensis in humans. P pasadenensis was detected by broad-range bacterial 16S rRNA PCR. Treatment consisted of surgical debridement and antibiotics, vancomycin and ciprofloxacin followed by clindamycin and ciprofloxacin, resulting in complete recovery.

Significance of Staphylococcus lugdunensis bacteremia: report of 28 cases and review of the literature.

BACKGROUND: Staphylococcus lugdunensis endocarditis has been associated with an aggressive course. The aim of this study was to determine factors associated with the development of endocarditis in patients with S. lugdunensis bacteremia. METHODS: A retrospective analysis of all patients with S. lugdunensis bacteremia in three tertiary care centers in Switzerland was performed. Data regarding medical history, symptoms, and susceptibility of S. lugdunensis isolates were collected. Our results were reviewed in the context of the current literature. RESULTS: A total of 28 patients with S. lugdunensis bacteremia were identified. Of the 13 patients with endocarditis, all were community acquired. Cardiac surgery was performed in 85% of these patients; mortality was 23%, reflecting the aggressive course of this disease. In contrast, in the 15 patients without endocarditis, no complications associated with S. lugdunensis bacteremia were observed. In 73%, a probable source was identified in the form of a venous catheter or other foreign device. Only three of these episodes were community acquired. No difference was observed in susceptibility of the S. lugdunensis isolates to penicillin, which was 77% in endocarditis isolates, and 87% in isolates of bacteremia without endocarditis, respectively. CONCLUSION: S. lugdunensis bacteremia is associated with endocarditis in up to 50% of patients. Every patient with community-acquired S. lugdunensis bacteremia should be carefully examined for signs of endocarditis. Once S. lugdunensis endocarditis is diagnosed, close monitoring is essential and surgical treatment should be considered early. In the nosocomial setting, endocarditis is far less frequent, and S. lugdunensis bacteremia is usually associated with a catheter or other foreign materials.

Identification and functional distribution of intracellular ca channels in mouse lacrimal gland acinar cells.

We have determined the presence and cellular distribution of intracellular calcium channels, inositol 1, 4, 5-trisphosphate receptors (IP3Rs) and ryanodine receptors (RyRs) in adult and postnatal (P10) lacrimal gland acinar cells. Western blot analysis of both P10 cultures and adult tissue identified the presence of each IP(3)R and RyR isotypes. The immunocytochemistry analysis showed a differential cellular distribution of these calcium channels where the nuclear envelope, endoplasmic reticulum (ER) and Golgi apparatus membranes represent areas with highest levels of channel expression. This IP(3)R and RyR isotype distribution is confirmed by the immuno-EM results. The findings described in this study are in agreement with published pharmacological data that shows the participation of these channels in the secretion process of the lacrimal gland acinar cells. Furthermore, the differential subcellular distribution between the isoforms could indicate a potential role of these intracellular Ca(2+ )channels on the regulation of specific cellular functions.

Rapidly destructive Staphylococcus epidermidis endocarditis.

A 29-year-old man with rapidly destructive Staphylococcus epidermidis endocarditis after mitral valve reconstruction is presented. Resistance to rifampin and teicoplanin occurred during antibiotic treatment resulting in clinical failure and valve destruction. Subsequently, the patient was successfully treated, by combining valve replacement with antibiotic therapy including quinupristin/dalfopristin, levofloxacin, and vancomycin. In conclusion, S. epidermidis can cause rapid valve destruction with large vegetations, and combination of surgery and antibiotic therapy may be necessary.

[Loa loa infection of the eye -- a case series]. / Loa-Loa-Infektion des Auges -- eine Fallserie.

BACKGROUND: With increasing migration tropical diseases such as Loa loa infections are becoming more frequent in Europe. While the ocular diagnosis is usually straight forward, systemic work-up and treatment requires an interdisciplinary approach. We review the diagnostic and therapeutic work-up of ocular Loa loa infections based on a series of 4 cases that presented between 1998 and 2004. HISTORY AND SIGNS: The first symptoms in all cases were ocular irritations occurring 2 months to 8 years after a trip to West Africa. One case presented with a swollen upper eyelid without a visible worm. In three patients microfilariae were detected in the blood. THERAPY AND OUTCOME: In two cases visible subconjunctival worms could be removed under the slit lamp. Three cases required systemic treatment as inpatients while one case could be observed without systemic treatment. All 4 cases had a favourable outcome with complete eradication of the disease. CONCLUSION: Surgical removal of adult Loa loa worms from the subconjunctival space only improves the ocular symptoms. An interdisciplinary approach (ophthalmology, infectious disease and parasitology) for a systemic work-up and treatment is usually required.

Long-term survival and interruption of HAART in HIV-related pulmonary hypertension.

Reported here is a case of a patient with pulmonary arterial hypertension related to HIV (PAHRH) in which lipodystrophy necessitated interruption of highly active antiretroviral therapy (HAART) and long-term survival was the outcome. Although previous studies have suggested antiretroviral therapy may benefit patients with this rare complication of HIV infection, no worsening of PAHRH was observed when HAART was interrupted. Clinical and echocardiographic parameters remained stable during 7 months of follow up. In cases in which HAART is associated with relevant toxicity, interruption of HAART in patients with PAHRH can be considered, but should be used only if no alternatives are available. Close follow-up is warranted.

Streptococcus pneumoniae as an uncommon cause of superinfected pancreatic pseudocysts.

We report a patient with pancreatic pseudocysts that were superinfected with Streptococcus pneumoniae. The literature on the prevalence of superinfection of pancreatic tissue by S. pneumoniae, as well as on its prophylaxis and treatment, is reviewed. In addition, a possible pathophysiologic pathway is discussed.

Marginal and subgingival plaque--a natural habitat of Tropheryma whipplei?

BACKGROUND: DNA of Tropheryma whipplei, the etiologic agent of Whipple's disease, has recently been detected in the saliva of healthy subjects. In this pilot study we searched for the habitat of T. whipplei within the oral cavity. MATERIALS AND METHODS: Samples from different oral sites were obtained from periodontically healthy volunteers, patients with progressive periodontitis and Chinese subjects with necrotizing ulcerative gingivitis or gingivitis. Quantitative real-time PCR was performed using T. whippleispecific primers, human beta-globin-specific primers to control for tissue DNA extraction and PCR reaction and broad-range eubacterial primers to control for bacterial DNA extraction. T. whipplei specificity of multiple amplicons was confirmed by sequencing. The detection limit of the method was 10 ag of T. whipplei DNA, corresponding to one to five bacteria under reference assay conditions. RESULTS: T. whipplei was found in the oral cavity of four out of ten healthy individuals from hospital staff and in three out of nine periodontitis patients, but in none of the individuals from China. All positive samples derived from subgingival and gingival sulcus plaque containing between 10(3) and 5 x 10(5) cells ml(-1) of plaque suspension, whereas saliva, smooth surface plaque and samples from the tongue or cheeks were negative. CONCLUSION: Our results suggest that T. whipplei colonizes the human body via the oral cavity and that bacterial plaques of the gingival crevice and the gingival sulcus/pocket may serve as a natural primary habitat.

Rat retinal progenitor cells and a retinal pigment epithelial factor.

Retinal progenitor cells were isolated from explants of neonatal rat retinas and characterized by transmission electron microscopy and reverse transcriptase-polymerase chain reaction and by their response to an isolated retinal pigment epithelial cell cell factor. The isolated progenitor cells demonstrated nuclei with abundant euchromatin typical of progenitor cells and showed the presence of nestin and opsin message. A protein ( approximately 67 kDa) isolated from conditioned media of cultured rat RPE cells promoted the survival of isolated retinal progenitor cells.

Positive regulation of motility and flhDC expression by the RNA-binding protein CsrA of Escherichia coli.

Many species of bacteria devote considerable metabolic resources and genetic information to the ability to sense the environment and move towards or away from specific stimuli using flagella. In Escherichia coli and related species, motility is regulated by several global regulatory circuits, which converge to modulate the overall expression of the master operon for flagellum biosynthesis, flhDC. We now show that the global regulator CsrA of E. coli K-12 is necessary for motility under a variety of growth conditions, as a result of its role as an activator of flhDC expression. A chromosomally encoded flhDC'-'lacZ translational fusion was expressed at three- to fourfold higher levels in csrA wild-type strains than in isogenic csrA mutants. Purified recombinant CsrA protein stimulated the coupled transcription-translation of flhDC'-' lacZ in S-30 extracts and bound to the 5' segment of flhDC mRNA in RNA mobility shift assays. The steady-state level of flhDC mRNA was higher and its half-life was approximately threefold greater in a csrA wild-type versus a csrA mutant strain. Thus, CsrA stimulates flhDC gene expression by a post-transcriptional mechanism reminiscent of its function in the repression of glycogen biosynthesis.

Immunolocalization of CD44 in the dystrophic rat retina.

The distribution of the cell surface adhesion/receptor molecule CD44 was studied in retinas of the Royal College of Surgeons (RCS) rat which exhibits an inherited retinal dystrophy. In this animal model, the retinal pigment epithelium fails to phagocytize shed photoreceptor outer segment material, a membranous debris layer accumulates in the subretinal space and the photoreceptor cells degenerate. Using immunoperoxidase and immunogold labeling, CD44 was localized to Müller cell apical microvilli in normal rat retinas, as noted in other species. For the RCS rat, immunoperoxidase labeling of 18 day and 1 month retinas showed the typical microvillar labeling pattern. At 2 months postnatal, following degeneration of most of the photoreceptors, a more condensed band of microvillar label was observed. At 3 months, when photoreceptor degeneration was virtually complete, only distinct regions of dense label remained between the neural retina and debris zone. Upon ultrastructural and immunogold analysis, these regions were found to contain closely packed Müller cell microvilli. At all ages studied, labeling for CD44 in the inner retina did not increase, as it does in other forms of retinal degeneration which lack a debris zone. However, by 3 months the debris zone was labeled for CD44 indicating that CD44 molecules remain on Müller cell microvilli and processes which have extended into and become part of the debris zone. This may be caused by an altered distribution of still undetermined ligands for CD44 which are present within the interphotoreceptor matrix of the RCS rat retina.