Evaluation of the TPX MRSA assay for the detection of methicillin-resistant Staphylococcus aureus.

The aim of this study was to evaluate a new type of assay for the phenotypic detection of methicillin-resistant Staphylococcus aureus (MRSA). The assay is based on a point-of-care compatible two-photon excitation fluorescence detection technology (TPX). A collection of 243 epidemic MRSA isolates was tested in addition to 138 sporadic MRSA and 101 negative control strains. The assay proved to be both sensitive (97.9%) and specific (94.1%) in the identification of MRSA, with adequate positive (98.4%) and negative (92.2%) predictive values. The time required for obtaining a positive test result was less than 14 h for 99.0% of the MRSA true-positive samples. After a test run, the selectively enriched reaction mixtures may be recovered and further studied by molecular or standard phenotypic methods. The main benefits of the TPX methodology include a simple assay procedure, low reagent consumption, and a high-throughput capacity.

Neurologic manifestations of infective endocarditis: a 17-year experience in a teaching hospital in Finland.

BACKGROUND: Many previous studies have endeavored to find appropriate means to reduce the occurrence of neurologic manifestations in patients with infective endocarditis (IE). We evaluated patients with IE-associated neurologic complications and compared them with patients with IE who did not have neurologic symptoms. Particular attention was focused on assessing the impact of cardiac surgery and the presence of potential risk factors for complications on the outcome of the patients. METHODS: A total of 218 episodes designated as definite or possible IE according to Duke criteria and treated during the years 1980 through 1996 in a Finnish teaching hospital were retrospectively evaluated for neurologic manifestations. RESULTS: Neurologic complications were identified in 55 episodes (25%), with an embolic event as the most frequent manifestation (23/55; 42%). In the majority (76%) of episodes, the neurologic manifestation was evident before antimicrobial treatment was started, being the first sign of IE in 47% of episodes. Only 1 recurrent cerebral embolization was observed. Neurologic complications were significantly associated with Staphylococcus aureus infection (29% vs 10%; P =.001) and with IE affecting both the aortic and the mitral valves (56% vs 23%; P<.01), but not with echocardiographic detection of vegetations or anticoagulant therapy. Death during the acute phase of IE occurred in 13 episodes (24%) with neurologic complications and in 17 episodes (10%) without neurologic complications (P<.03). In episodes with neurologic complications, the IE-associated mortality rate was 25% (10/40) in the medical treatment group and 20% (3/15) in the surgical group. No neurologic deterioration was observed in these surgically treated patients postoperatively. CONCLUSIONS: Our results reinforce the belief that rapid diagnosis and initiation of antimicrobial therapy may still be the most effective means to prevent neurologic complications. These data underscore the importance of diagnostic alertness to the prognosis of patients with IE.

Diagnosis of infective endocarditis. Sensitivity of the Duke vs von Reyn criteria.

BACKGROUND: Because of the highly variable clinical manifestations of infective endocarditis (IE), different sets of diagnostic criteria have been used to standardize case definitions of IE. We evaluated the validity of the recently proposed Duke criteria, as compared with the older von Reyn criteria, in patients with no history of injecting drug abuse. METHODS: A total of 243 consecutive episodes of suspected IE in 222 patients treated during the years 1980 through 1995 in a Finnish teaching hospital were retrospectively evaluated for the likelihood of IE by means of these 2 classification schemes. RESULTS: Of all disease episodes, 114 were designated as definite IE by the Duke criteria, as compared with 64 episodes so classified by the von Reyn criteria (P < .001; Fisher exact test). Moreover, as many as 115 disease episodes were rejected by the von Reyn criteria, whereas only 37 episodes were rejected by the Duke criteria (P < .001). Of the cases rejected by the von Reyn criteria, the Duke clinical criteria designated 6 (5%) as definite IE and 72 (63%) as possible IE. Among histopathologically verified episodes, 46 were designated as definite IE by the Duke clinical criteria, as compared with a diagnosis of probable IE by the von Reyn criteria in 33 episodes (P = .02). Moreover, 26 pathologically proved cases would have been rejected by the von Reyn criteria had surgery not been performed, as compared with none being rejected by the Duke criteria (P < .001). CONCLUSIONS: Corroborating earlier findings, the higher sensitivity of the Duke criteria, as compared with the von Reyn criteria, was demonstrated in this study. These results confirm the validity of the Duke criteria in diagnosing IE in a non-drug-addict patient population.

Eradication of methicillin-resistant Staphylococcus aureus from a health center ward and associated nursing home.

BACKGROUND: Long-term health care facilities have been recognized as reservoirs of multiresistant bacterial strains, especially methicillin-resistant Staphylococcus aureus (MRSA). Efforts to control MRSA in this setting usually have been only partially effective. We describe herein the eradication of epidemic MRSA from a Finnish health care center ward and affiliated nursing home. METHODS: The methods to control MRSA included (1) contact isolation precautions, (2) screening for asymptomatic carriage, (3) eradication of carriage, and (4) education of staff on hygienic measures. The first 6 patients with MRSA-positive findings were referred without delay to the Infectious Diseases Unit of the adjacent university hospital for eradication treatment. Later, an isolation unit of 6 rooms was founded in the health care center, where the MRSA-colonized patients were nursed as a separate cohort until they, in succession, were referred to the Infectious Diseases Unit for decolonization. RESULTS: From May 20 through August 17, 1993, the epidemic MRSA strain was isolated from 8 long-term patients on the 40-bed ward of the health care center, 4 of the 59 residents of the nursing home, and 1 member of the staff. Eradication of carriage was successful in all except 1 patient with dementia, who was nursed in contact isolation in the health care center until his death 21 months later. CONCLUSIONS: It is possible to eradicate MRSA from a long-term health care facility even after 13 cases by applying strict control measures. Our experience may be valuable in the future decision-making process for control of new and more challenging multiresistant bacteria, eg, vancomycin-resistant strains of MRSA.

Comparison of amplitude-modulated (direct) and frequency-modulated ambulatory techniques for recording ischemic electrocardiographic changes.

Continuous ambulatory electrocardiographic monitoring of ST-segment configuration has become a useful technique for evaluation of myocardial ischemia. Concern that direct or amplitude-modulated (AM) recording and playback systems have inherent limitations that cause inaccurate ST-segment recordings has led to preference for frequency-modulated (FM) devices. To determine the accuracy of AM and FM ambulatory electrocardiographic systems, the signal was compared from the same set of 2 bipolar leads simultaneously recorded by standard electrocardiography and AM and FM recorders in 14 patients during treadmill exercise. Also, simultaneous AM and FM recorders were compared in 9 ambulatory patients in 16 monitoring sessions. The AM recording system accurately reproduced ST segments recorded during treadmill exercise (range 4.0 mm of ST-segment depression to 2.0 mm of ST elevation) when measured at the J point (r = 0.91, p less than 0.0001), and 0.08 second after the J point (r = 0.95, p less than 0.0001). FM recording was equally accurate (r = 0.89 and 0.95, respectively, p less than 0.0001). Similarly, during ambulatory recording, the AM technique accurately recorded maximal ST depression in each episode as recorded by the FM device (28 episodes, range 0 to 3 mm of ST depression, r = 0.85, p less than 0.0001). Both AM and FM ambulatory electrocardiographic systems can accurately reproduce ST-segment deviation associated with ischemia and can be used to monitor transient ST-segment changes in patients with coronary artery disease.

Intraaortic balloon counterpulsation in a community hospital.

Our experience with intraaortic balloon counterpulsation in 41 patients documents the feasibility of a coordinated aggressive therapeutic approach in patients with potentially fatal complications of coronary artery disease. The use of intraaortic balloon pump in a non-cardiac surgical center has allowed hemodynamic support in the critically ill, safety in angiography, appropriate selection of patients for surgery, and safe transportation to a cardiac surgery center when indicated.

Cardiac response during uninterrupted treadmill exercise and recovery: measurement by systolic time intervals.

In 12 normal subjects, use of ear densitography permitted measurement of systolic time intervals (STI) during uninterrupted treadmill exercise to over 90 percent maximal heart rate on a modified Bruce protocol. Results for control (sitting leads to standing) leads to end-exercise at 18 minutes leads to 10 minutes' sitting recovery were--heart rate (HR): (77 leads to 861 leads to 171 leads to 98 beats per minute; preejection period (PEP): (106 leads to 111) leads to 49 leads to 110 msec; ejection time index (ETI) (351 leads to 330) leads to 380 leads to 366 msec; PEP/LVET (0.42 leads to 0.49) leads to 0.29 leads to 0.45. Heart rate increased steadily to 18 minutes. In contrast, the PEP/LVET decrease was almost complete by three minutes and both ETI and PEP responses were bimodal with respective plateaus between three and six minutes and three and nine minutes. All STI and HR curves showed rapid restitution during early recovery. The changes during treadmill exercise were numerically comparable to those during bicycle exercise at a common heart rate. The results indicate that it is technically feasible to measure systolic time intervals with precision during uninterrupted treadmill exercise; responses to treadmill exercise were in the direction expected and quantitatively comparable to bicycle exercise at comparable stress level. These obervations provide the technical and physiologic bases for applying this method in clinical treadmill exercise testing.

Multiresistance in Staphylococcus spp. blood isolates in Finland with special reference to the distribution of the mecA gene among the Staphylococcus epidermidis isolates. The Finnish Study Group for Antimicrobial Resistance.

A total of 570 Staphylococcus spp. blood isolates collected in Finland in 1991 were tested for susceptiblity to oxacillin and 19 additional antimicrobial agents. The Staphylococcus epidermidis isolates were also analyzed for the presence of the mecA gene by the polymerase chain reaction (PCR). Of the 238 S. epidermidis, 137 (58%) were in vitro identified as methicillin-resistant and 5 (2%) exhibited oxacillin MICs between 1 and 3 micrograms/ml. All these isolates were positive for the mecA gene in PCR as an indication of genetic resistance to methicillin, while none of the remaining 96 S. epidermidis isolates (oxacillin MICs < or = 0.25 microgram/ml) was positive. Multiresistance was observed in 123 (87%) of the 142 mecA-positive S. epidermidis. Of the 332 Staphylococcus aureus isolates, only one (0.3%) was phenotypically resistant to methicillin; the strain was also resistant to three other unrelated classes of antimicrobials. True methicillin resistance of this strain was manifested by the presence of the mecA gene in PCR. Based on these results, multiresistance was still extremely rate among the S. aureus in our country, whereas among the S. epidermidis as many as half of the blood isolates in central hospitals were multiresistant.

Presence of parvovirus B19 DNA in chronic urticaric and healthy human skin.

BACKGROUND: The etiology of chronic urticaria is undefined, but the potential role of infectious agents as one triggering factor has been suggested. The appearance of chronic urticaria in a 16-year old male after a history of a recent parvovirus B19 (B19) infection led us to investigate the association between B19 and chronic urticaria. OBJECTIVES: To investigate whether parvovirus B19 (B19) has a role in chronic urticaria. STUDY DESIGN: We amplified B19 DNA from skin biopsy samples of 36 adult chronic urticaria patients as well as of 22 healthy controls using two sets of separate primers and probe. Circulating IgG and IgM antibodies to B19 were measured from 27 patients and from all controls. RESULTS: B19 DNA was detected in 18 (50%) skin biopsy samples of 36 patients with chronic urticaria. Unexpectedly, also 14 (64%) skin biopsy samples from 22 healthy controls harbored B19 DNA. All 32 persons with positive B19 PCR findings had circulating IgG-class antibodies to B19 major structural protein VP2, but no IgM antibodies. CONCLUSION: Our results show that B19 DNA commonly exists in human skin. Therefore, the association between B19 infection and chronic urticaria remains uncertain. However, these findings raise the question whether the skin may constitute a reservoir for B19.

Parainfluenza virus type 3 infections in a hematology unit.

Parainfluenza virus type 3 (PIV3) is associated with a high mortality rate in BMT recipients with lower respiratory tract infections. We describe nine patients with hematological malignancies (five having undergone either allogeneic or autologous stem cell transplantation) identified as having PIV3 infection during a 2-month period in a Hematology Unit. Four patients with infiltrates on chest radiograph received intravenous ribavirin therapy; all survived. The infection was community-acquired in two patients, while nosocomial origin of the disease was evident, or presumed, in the remaining seven. The policy implemented to control the spread of PIV3 was as follows: (1) nasopharyngeal samples for antigen detection were obtained from all patients presenting with respiratory symptoms; (2) all diagnosed (or suspected) PIV3-positive hematological patients were nursed following contact isolation precautions, preferably in the Infectious Diseases Unit; and (3) staff were given further education on hospital hygiene. Our experience shows that it may be possible to avoid mortality for PIV3 lower respiratory tract infection in immunocompromised patients by early commencement of intravenous ribavirin. It is also possible, even without closing the ward, to contain nosocomial spread of PIV3 by implementing systematic nasopharyngeal sampling for rapid diagnostics, and by strict adherence to cohorting and contact isolation precautions.

Infrequent isolation of multiresistant Acinetobacter baumannii from the staff tending a colonized patient with severe burns.

A patient with severe burns who was colonized by multiresistant Acinetobacter baumannii was cared for in contact isolation by staff intensively trained on hospital hygiene. Of the 1,907 postexposure cultures from the staff and 425 environmental samples, only 0.7% and 4%, respectively, yielded this microorganism. These data show that strict hygienic measures may limit staff colonization and contamination of the environment byA baumannii.

Eradication of the long-term carriage of methicillin-resistant Staphylococcus aureus in patients wearing dentures: a follow-up of 10 patients.

To cure the long-term carriage of methicillin-resistant Staphylococcus aureus (MRSA), eradication treatment was given to 10 patients wearing complete dentures. In addition to multiple body sites, MRSA was cultured from the dentures of six patients. The contaminated dentures were rebased and sterilized with heat in order to prevent recolonization. The patients did not use their dentures during the decolonization therapy. Subsequently, MRSA was eradicated from three of these patients but three others remained MRSA-positive despite at least two courses of combined systemic and topical eradication treatment. These particular patients had persistent stomatitis and their dentures were a poor fit, in poor condition and repeatedly grew MRSA. Eradication treatment was successful in the remaining four patients whose dentures were MRSA-negative. These results confirm that dentures may function as foreign bodies and sustain persistent nasopharyngeal. MRSA colonization. Therefore, we suggest that whenever eradication of MRSA is deemed necessary in cases of nasal, oral or pharyngeal carriage, heat treatment of the dentures should be included. Further comparative studies with larger patient populations are needed to evaluate the contribution of dentures to the long-term carriage of MRSA, as well as to assess the value of denture sterilization during the eradication course.