Making real sense of MRSA.
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Cross Infection↗
Biomedical subjects
J E Patterson
Publications and source records attributed to J E Patterson.
Serological investigation of enterococcal infections using western blot.
To assess the usefulness of Western blot in the diagnosis of enterococcal infections, a pilot study was conducted with a newly developed Western blot using sera from patients with confirmed enterococcal infections. Sera from 17 of 19 patients with enterococcal endocarditis reacted strongly to enterococcal antigens on the Western blot, and most produced specific bands at molecular weights 98 kDa and 54 kDa. Sera from patients with bacteremic cholangitis and pyelonephritis reacted frequently as well, but the pattern of bands was different from that observed with endocarditis. Eighty-five percent of 26 sera tested from patients with bacteremia and associated deep-seated infections (endocarditis, cholangitis, and pyelonephritis) were positive on Western blot, compared to 30% of sera from bacteremic patients with no clinically determined deep focus of infection (p < 0.001).
Antibodies, Bacterial↗
Use of pulsed-field gel electrophoresis typing to study an outbreak of infection due to Serratia marcescens in a neonatal intensive care unit.
Serratia marcescens is a well-known cause of nosocomial infections and outbreaks, particularly in critically ill neonates and immunocompromised patients. Numerous methods have been proposed for typing. We used pulsed-field gel electrophoresis (PFGE) typing to analyze an outbreak in a neonatal intensive care unit (NICU). We included 23 patient isolates from an outbreak (March to July 1995), and 10 patient isolates from different wards during the same time period. PFGE of whole-cell DNA digested by SpeI was used as a marker of strain identity. The most common presentation of the infection was sepsis in 18 of 23 (78%) neonates. Only four different biotypes were identified; biotype A8d accounted for 84% of the strains. PFGE typing revealed two clones responsible for two different clonal strain dissemination outbreaks from March to July, with 24 patient isolates being pattern A and 4 patient isolates being pattern E. PFGE typing suggests cross transmission between patients in the NICU and other wards. The isolates from 5 other patients showed distinct PFGE patterns. Extensive investigation and cultures failed to identify any environmental or staff reservoir of S. marcescens. This is one of the first reports applying PFGE to the study of S. marcescens, and this method was a useful marker of strain identity. PFGE typing distinguished strains which appeared to be the same by biotyping.
Bacterial Typing Techniques↗
Evaluation of pulsed-field gel electrophoresis as a typing system for Candida rugosa: comparison of karyotype and restriction fragment length polymorphisms.
Nosocomial infections with Candida species have emerged as an increasingly important cause of morbidity and mortality in intensive care units. Ten Candida rugosa isolates from a previously documented cluster of C. rugosa infections in one hospital (nine burn unit isolates and one isolate from another hospital ward) and eight C. rugosa isolates recovered in a referral fungus testing laboratory (comparison isolates) from distinct geographic areas were investigated by molecular techniques. Isolates were from multiple anatomic sites. Pulsed-field gel electrophoresis (PFGE) of whole-cell DNA was performed with the 18 C. rugosa isolates as a marker of strain identity. The PFGE karyotypes of the C. rugosa isolates were demonstrated from four to seven chromosome bands. Karyotyping revealed the same PFGE pattern for the nine outbreak isolates from the burn unit, confirming clonal strain transmission. The isolate from the other hospital ward had a distinct karyotype. Distinct PFGE karyotype patterns were demonstrated for the eight comparison isolates. Restriction fragment length polymorphisms (RFLP) generated from whole-cell DNA digested with SfiI demonstrated the same RFLP pattern among outbreak isolates. Among comparison isolates, karyotyping distinguished some isolates that were indistinguishable by RFLP patterns. Karyotyping by PFGE appears to be the most useful molecular typing tool for discrimination among strains of C. rugosa and will be a useful marker for evaluating the epidemiology of future C. rugosa infections.
Candida↗
Regression and progression of Barrett's oesophagus after antireflux surgery.
The effects of antireflux surgery on Barrett's oesophagus were studied. Fifty-six patients (45 men and 11 women of median age 48.5 (range 20-78) years) with histologically confirmed Barrett's oesophagus (greater than 3 cm in length) and gastro-oesophageal reflux underwent antireflux surgery. Symptoms were noted and patients underwent manometry and pH recording before and after operation, and annual flexible endoscopy. Fundoplication resulted in a significant improvement in lower oesophageal sphincter pressure (median (interquartile range (i.q.r.)) 8 (5-14) mmHg before operation versus 17 (11-22) mmHg after operation, P < 0.001). Twenty-four of the 56 patients had partial or complete regression of Barrett's oesophagus (median (i.q.r.) length 8 (3-18) cm before versus 4 (0-10) cm after operation, P < 0.001) but nine showed progression (median (i.q.r.) length 6 (3-11) cm before versus 10 (6-15) cm after operation, P < 0.01) (median follow-up 5.5 (range 2.0-10.5) years). Carcinoma developed in one patient. The length of Barrett's oesophagus was unchanged in 23 patients. Regression was more likely to occur in patients who underwent fundoplication with previous or concomitant vagotomy (chi 2 = 7.21, 1 d.f., P < 0.01) and in those with a good symptomatic result (chi 2 = 23.52, 1 d.f., P < 0.001).
Adult↗
The evolving epidemiology of methicillin-resistant Staphylococcus aureus at a university hospital.
OBJECTIVE: To describe the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) at a university hospital during a 14-month period. DESIGN: Prospective laboratory-based surveillance for MRSA with descriptive epidemiology based on medical chart review and characterization of strains by DNA typing, using pulsed-field gel electrophoresis (PFGE). SETTING: An 850-bed tertiary care university hospital. PATIENTS: Patients with clinical isolates of MRSA. MAIN OUTCOME MEASURE: Determination whether MRSA isolates were community- or hospital-related. RESULTS: Among 87 patients with MRSA, 36 (41%) had community-acquired infections. Community acquisition was associated with recent hospitalization, previous antibiotic therapy, nursing home residence, and intravenous drug use. Greater than 3 months had elapsed from the time of discharge for 13 (62%) of the 21 patients with community-acquired isolates hospitalized within the last year. Eight patients (22%) with community-acquired MRSA had no discernible risk factors. PFGE allowed differentiation of 35 distinct whole-cell DNA patterns; heterogeneity was seen among both nosocomial and community-acquired isolates, with few instances of cross-transmission. CONCLUSIONS: Our data suggest an increase in community acquisition of MRSA. PFGE demonstrated heterogeneity of MRSA isolates from both the community and the hospital setting.
Adolescent↗
Molecular heterogeneity of Acinetobacter baumanii isolates during seasonal increase in prevalence.
OBJECTIVE: To study the epidemiology of Acinetobacter baumanii during a period of increased seasonal prevalence. DESIGN: Descriptive molecular and clinical epidemiologic study of A baumanii isolates from 1990 through 1992. SETTING: A 770-bed urban, acute, tertiary-care university hospital. RESULTS: During 1990 through 1992, the rate of A baumanii isolations was 30.4 per 1,000 culture isolations during the summer, compared to 12.6 per 1,000 culture isolations during the fall, winter, and spring (P < .000001). There were 320 isolates identified among 260 patients during this time. Eighty-one patients with isolates available were identified for evaluation; they ranged in age from 2 months to 95 years. Pulsed-field gel electrophoresis (PFGE) typing showed that 59 (83%) of 71 typed isolates had distinct PFGE patterns. There were three small clusters of isolates with the same PFGE patterns, suggesting cross-transmission in those instances. CONCLUSIONS: A seasonally increased prevalence of A baumanii largely associated with device-related nosocomial infections in severely ill patients was noted over a 3-year period. Although there were isolated instances of cross-transmission, most isolates had distinct PFGE patterns. Clonal dissemination of a single strain was not responsible for the seasonal increased prevalence of A baumanii. PFGE typing was useful in directing control efforts.
Acinetobacter↗
Clinical and molecular epidemiology of vancomycin-resistant Enterococcus faecium during its emergence in a city in southern Texas.
During a 19-month period from April 1993 to October 1994, 41 isolates of vancomycin-resistant Enterococcus faecium (VREF) were detected in seven different hospitals in a city in southern Texas. A case-control study to determine the risk factors for acquisition was done in the hospital in which the majority of isolates were detected. Pulsed-field gel electrophoresis (PFGE) of whole-cell DNA was used to determine strain identity. Thirty-five (85%) of the 41 VREF isolates were of the vanB phenotype. Of these, 32 (91%) of 35 were the same strain by PFGE typing. The same vanB strain was documented in five different hospitals in the city. In contrast, 4 (67%) of 6 of the vanA phenotype VREF isolates were distinct strains by PFGE typing. Significant risk factors for colonization or infection with VREF were prior exposure to antibiotics (P = .04), the previous use of third-generation cephalosporins (P = .03), and the previous use of parenteral vancomycin (P = .002). Infection-control and antibiotic-utilization measures were implemented to control cross-transmission and selection of VREF isolates. During the emergence of VREF in our city, clonal dissemination of a single strain of vanB VREF among six hospitals was documented. Limited cross-transmission of vanA phenotype VREF isolates occurred, but most vanA VREF isolates were distinct strains selected in individual hospital environments.
Anti-Bacterial Agents↗
Methicillin-resistant Staphylococcus aureus as a community organism.
An increase in methicillin-resistant Staphylococcus aureus (MRSA) infections prompted a study of MRSA during a 21-month period in a 600-bed university hospital in southern Texas. MRSA cases were classified as community, nosocomial, or transfer cases. A case-control study of risk factors for community MRSA compared with community methicillin-susceptible S. aureus (MSSA) was performed. Pulsed field gel electrophoresis (PFGE) of whole cell DNA typing was used as a marker of strain identity for 31 consecutive isolates collected during the last 8 months of the study. During the 21 months there were 170 patients with MRSA infection or colonization, an incidence of 0.2 per 1,000 patient-days. Ninety-nine (58%) of 170 isolates were from community cases; the community to nosocomial case ratio was 2:1. No significant risk factors differentiated patients with community MRSA compared with community MSSA. Most community MRSA isolates studied (15 [68%] of 22) had distinct PFGE patterns, as did many nosocomial MRSA isolates (4 [44%] of 9). MRSA isolates were commonly present on admission to the hospital, and multiple MRSA strains were demonstrated among both community and hospital isolates.
Adult↗
Incidence of hemolysin, gelatinase, and aggregation substance among enterococci isolated from patients with endocarditis and other infections and from feces of hospitalized and community-based persons.
The presence of hemolysin, gelatinase, and aggregation substance (by use of a probe known to hybridize to most pheromone-responsive plasmids) was determined in 192 isolates of Enterococcus faecalis from patients with endocarditis or other infections and fecal isolates from hospitalized patients or healthy volunteers, and in 86 non-E. faecalis isolates. Hemolysin was more common in nonendocarditis clinical isolates and in hospital fecal isolates (37% and 31%, respectively) than among endocarditis and community fecal isolates (16% and 20%, respectively). Gelatinase and aggregation substance, respectively, were found in 54% and 52% of isolates from endocarditis, in 58% and 72% of isolates from other infections, in 62% and 56% of hospital fecal isolates, and in 27% and 30% of fecal isolates from healthy volunteers. All 86 non-E. faecalis enterococcal isolates were negative for these traits. The absence of hemolysin, gelatinase, or the aggregation substance gene in > 45% of endocarditis E. faecalis isolates suggests that while these traits may play a role in virulence, other properties are also important.
Bacterial Proteins↗
Aspergillus antigen detection in the diagnosis of invasive aspergillosis.
The utility of serum Aspergillus antigen in invasive aspergillosis was determined by identifying patients with >50 ng/mL Aspergillus carbohydrate antigen by ELISA. Patients were identified from a university hospital over a 65-month period. Nineteen patients with antigenemia had proven invasive aspergillosis, 16 had probable invasive aspergillosis, and 14 had an indeterminate diagnosis. There were 5 patients with false-positive results. Antigen levels were higher in disseminated infection than in invasive pulmonary aspergillosis (median levels, 500 and 121 ng/mL, respectively). Survival also correlated with antigenemia. Serial samples were obtained from 31 of 35 patients with proven or probable invasive aspergillosis. Fifteen of 19 patients with rising or persistent antigenemia died, whereas only 1 of 12 patients who cleared antigenemia died. Higher antigen levels were useful in predicting disseminated disease, and the course of antigenemia correlated with clinical outcome. Antigen detection may be a useful addition in the management of invasive aspergillosis.
Antigens, Fungal↗
The clinical and molecular epidemiology of bacteremias at a university hospital caused by pneumococci not susceptible to penicillin.
To determine the epidemiology of bacteremias due to pneumococci not susceptible to penicillin (PNSP) at a university hospital, active microbiologic surveillance of bacteremias due to PNSP was done for 28 months. Controls were bacteremias caused by penicillin-susceptible pneumococci. Antimicrobial susceptibilities for alternative antibiotics were determined. Pulsed-field gel electrophoresis (PFGE) and serotyping were used as markers of strain identity. Of 113 pneumococcal isolates, 14 (13%) were intermediate or resistant to penicillin (MIC > or = 0.1 microgram/mL). Twelve PNSP were resistant to other drugs: chloramphenicol (5), tetracycline (6), trimethoprim-sulfamethoxazole (5), cefotaxime (1), and erythromycin (1). Independently significant risk factors associated with PNSP bacteremia were sepsis and prior treatment with beta-lactam antibiotics. PFGE revealed 10 distinguishable patterns among 12 isolates available for typing. In general, PFGE typing correlated with serotyping. It also distinguished some isolates of the same serotype. PFGE typing and serotyping suggest that the frequency of PNSP in the San Antonio, Texas, area is not due to dissemination of a single clonal strain.
Adolescent↗
Nursing consultation to reduce restraints in a nursing home.
Consultation is an important function of advanced practice nurses. Within nursing practice, the process of providing consultation has been studied primarily in acute care settings. A CNS in a 180-bed, nonprofit nursing home implemented the intervention for a controlled clinical trial of nursing interventions to reduce physical restraint use. The consulting process undertaken by the CNS is described, and conclusions are offered regarding the most effective approaches to consultation by advanced practice nurses in nursing homes.
Consultants↗
An analysis of 110 serious enterococcal infections. Epidemiology, antibiotic susceptibility, and outcome.
A prospective, observational study of 110 patients with serious infections due to Enterococcus spp. in 6 university and community teaching hospitals in Connecticut was conducted to define the epidemiology of community and nosocomial serious enterococcal infections and to determine risk factors, including antibiotic resistances, that contribute to outcome. Serious community and nosocomial enterococcal infections involved a variety of sites, and antibiotic resistance was common. Types of infection by major organ system were cardiovascular, 54% (catheter-related bacteremia 28%, primary bacteremia 18%, endocarditis 6%, septic thrombophlebitis 1%); intra-abdominal, 13% (including cholangitis, 6%); renal, 13%; skin and soft tissue, 5%; bone and joint, 4%; pleuropulmonary, 4%; central nervous system, 3%; deep surgical wound, 3%; and endometritis, 2%. Sixty-one percent of infections were nosocomial; 48% of these occurred in the intensive care unit. Enterococcus faecium was responsible for 20% of all infections. Antibiotic resistances among the infections included high-level gentamicin resistance (26%), ampicillin resistance (10%), and vancomycin resistance (8%). Clinical cure was achieved in 64% of patients; 6.8% of patients relapsed, 6.8% had recurrence of the infection with a different pathogen, and overall mortality was 23%. Ampicillin resistance and a high acute physiology and chronic health evaluation (APACHE) II score were highly predictive of lack of cure.
Adolescent↗
Intra-vesical foreign body: an unusual cause.
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Adult↗
Bacterial urinary tract infections in diabetes.
Bacterial UTIs are a common problem in patients with diabetes mellitus. Bacteriuria is more common in diabetic women than in non-diabetics owing to a combination of host and local risk factors. Upper tract disease is also more common in this group. Diabetics are at higher risk for intrarenal abscess, with a spectrum of disease ranging from acute focal bacterial pyelonephritis to renal corticomedullary abscess to the renal carbuncle. A number of uncommon complicated UTIs, such as emphysematous pyelonephritis and emphysematous pyelitis, occur more frequently in diabetics. Because of the frequency and severity of UTI in diabetics, prompt diagnosis and early therapy is warranted.
Abscess↗
Extraction of an intravesical thermometer using a flexible cystoscope.
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Cystoscopes↗
Special organism isolation: attempting to bridge the gap.
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Acinetobacter↗