Plasmid-mediated induction of recombination in yeast.

Diploid yeast cells heteroallelic at the HIS3 locus were transformed with a minichromosome (centromeric plasmid) carrying homology to the HIS3 region and containing the same two mutations as were present in the chromosomes. When a double-strand break (DSB) was introduced in the region of homology, an increase in the recombination frequency between heteroalleles (leading to His+ cells) was observed, although the plasmid was unable to donate wild-type information. This induction of recombination was dependent on the presence of homology between the plasmid sequences and the chromosomes. We show evidence for the physical involvement of the plasmid in tripartite recombination events, and we propose models that can explain the interactions between the plasmid-borne and chromosomal-borne alleles. Our results suggest that the mitotic induction of recombination by DNA damage is due to localized initiation of recombination events, and not to a general induction of recombination enzymes in the cell.

Nosocomial Malassezia pachydermatis bloodstream infections in a neonatal intensive care unit.

Malassezia pachydermatis, a lipophilic yeast, has been described to cause sporadic nosocomial bloodstream infections (BSI). Nosocomial outbreaks of M. pachydermatis BSI have never been described. A cluster of M. pachydermatis BSIs in the neonatal intensive care unit at Louisiana State University Medical Center, University Hospital provided the opportunity to investigate the epidemiology of this organism and apply molecular epidemiologic typing techniques. A case-patient was defined as any neonatal intensive care unit patient in University Hospital with a blood culture positive for M. pachydermatis from January 1, 1989, through August 15, 1991. Five patients met the case definition. Case-patients were premature as estimated by gestational age and required prolonged hospitalization. Case-patients received parenteral nutrition and intravenous lipids for twice as many days as randomly selected controls. No environmental source of M. pachydermatis was identified; however, infants on each side of a previously identified M. pachydermatis-colonized infant became colonized with M. pachydermatis during a 20-day period. Chromosomal analysis of five M. pachydermatis blood isolates from two case-patients had identical banding patterns. These data show that M. pachydermatis can cause nosocomial BSI outbreaks, that premature infants receiving parenteral nutrition and/or lipids may be at greatest risk and that transmission is most likely from person to person, probably via the hands of medical personnel.

Candida parapsilosis bloodstream infections in neonatal intensive care unit patients: epidemiologic and laboratory confirmation of a common source outbreak.

BACKGROUND: Candida parapsilosis is a common cause of sporadic and epidemic infections in neonatal intensive care units (NICUs). When a cluster of C. parapsilosis bloodstream infections occurred in NICU patients in a hospital in Louisiana, it provided us with the opportunity to conduct an epidemiologic investigation and to apply newly developed molecular typing techniques. METHODS: A case-patient was defined as any NICU patient at Louisiana State University Medical Center, University Hospital, with a blood culture positive for C. parapsilosis during July 20 to 27, 1991. To identify risk factors for C. parapsilosis bloodstream infection, a cohort study of all NICU infants admitted during July 17 to 27, 1991, was performed. Electrophoretic karyotyping was used to assess the relatedness of C. parapsilosis isolates. RESULTS: The receipt of liquid glycerin given as a suppository was identified as a risk factor (relative risk, 31.2; 95% confidence intervals, 4.3 to 226.8). Glycerin was supplied to the NICU in a 16-oz multidose bottle. Bottles used at the time of the outbreak were not available for culture. All six available isolates from four case-patients had identical chromosomal banding patterns; six University Hospital non-outbreak isolates had different banding patterns. CONCLUSIONS: This study demonstrates the utility of combined epidemiologic and laboratory techniques in identifying a novel common source for a C. parapsilosis bloodstream infection outbreak and illustrates that extreme caution should be exercised when using multidose medications in more than one patient.

Acalculous cholecystitis and septicemia caused by non-O1 Vibrio cholerae: first reported case and review of biliary infections with Vibrio cholerae.

The first case of septicemic acute acalculous cholecystitis caused by non-O1 Vibrio cholerae is described in a healthy traveler, and biliary tract infections from V. cholerae are reviewed. Immediately after a vacation in Cancun, Mexico, a 55-year-old man developed acute cholecystitis. Blood and bile cultures grew non-O1 V. cholerae. At surgery, the gallbladder was acalculous, inflamed, distended, and nearly ruptured. Pathogenetic factors may have included diarrhea prophylaxis with bismuth subsalicylate, distension of the gallbladder from illness-induced fasting, and bacterial toxins in the gallbladder. The patient received i.v. cephapirin, followed by oral cephradine for a total of 10 days, and he made a quick and complete recovery. V. cholerae should be considered in the differential diagnosis of persons from endemic areas who present with cholecystitis or acute jaundice.

Comparison of two selective media developed to isolate Pseudomonas cepacia from patients with cystic fibrosis.

Two media selective for Pseudomonas cepacia have been described recently: OF-polymyxinbacitracin-lactose agar (OFPBL) and P. cepacia agar (PCA). We compared these by culturing sputum from 27 patients with cystic fibrosis. Sputum from each patient was studied using streak-plate (SP) and quantitative (Q) culture methods. Five strains of P. cepacia were isolated from four patients (15%). P. cepacia was not found on routine media by SP or Q methods in three of the four patients. All five isolates grew on both OFPBL and PCA and all were recovered by SP and Q culture methods. Colony counts of P. cepacia obtained by Q cultures were similar on both selective media. Each of the selective media allowed the growth of other organisms; nineteen of 27 specimens cultured on OFPBL yielded non-P. cepacia spp. and six of 27 specimens cultured on PCA yielded non-P. cepacia spp. species (p less than 0.005). Pseudomonas aeruginosa was isolated from 26 of 27 patients on routine media (96%). This organism was recovered from four specimens cultured on OFPBL but from none on PCA (p less than 0.05). OFPBL and PCA are both selective for P. cepacia and enhance the ability to recover this organism from patients with cystic fibrosis using either SP or Q cultures of sputum; however, PCA is significantly more inhibitory for non-P. cepacia spp. than OFPBL.

Evaluation of an intervention program in the control of an urban outbreak of shigellosis.

Community-wide outbreaks of shigellosis are a persistent public health problem. We evaluated the effect of a household-based intervention program on the control of an urban outbreak of S. sonnei gastroenteritis. During the intervention we attempted to contact all households with culture-confirmed S. sonnei and provide education in methods to prevent spread of Shigella. Subsequently we conducted a survey of intervention (n = 43) and nonintervention (n = 33) households. We also conducted a serosurvey of children three to five years of age. The number of new cases of S. sonnei infection declined steadily over several months after the intervention began. Members of the intervention households were more knowledgeable about handwashing (rate ratio [RR] 4.7, 95% confidence interval [CI] = 2.1-10.8) and others methods of S. sonnei transmission and control than members of nonintervention households. However, intervention households had higher attack rates of Shigella-associated diarrhea in susceptible household members (RR 1.4, 95% CI = 1.0-2.0). During the intervention we were able to contact only 25% of households by the eighth day after onset of diarrhea in the index case, when 90% of intrahousehold transmission of Shigella had already occurred. Two months after the outbreak ended, 42% of children in the outbreak community had elevated antibody titers against S. sonnei; an additional 19% had borderline elevated titers. The intervention program improved knowledge but may have occurred too late to prevent intrahousehold transmission of Shigella. Exhaustion of susceptible hosts, rather than the education program, likely accounted for the decline in shigellosis cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross-modal exercise prescription at absolute and relative oxygen uptake using perceived exertion.

Cross-modal exercise prescription at absolute and relative oxygen uptake using perceived exertion. Med. Sci. Sports Exerc., Vol. 22, No. 5, pp. 653-659, 1990. The validity of cross-modal prescription of exercise intensity based on rated perceived exertion (RPE) was determined for eight men (26 +/- SE 1.9 yr) at absolute and relative VO2. Exercise modes were treadmill (TM), cycle ergometer (C), and bench stepping while pumping 0.91 kg handweights (HB). Relative (Rel) constant load sessions were performed for each mode at 70% of mode-specific VO2 peak. Absolute (Absol) constant load sessions were performed for C and HB at the VO2 equivalent to 70% of TM VO2 peak. The five 12 min sessions were presented on separate days in random order. RPE-Overall during TM-Rel (11.1) was a) lower (P less than 0.05) than C-Absol (12.6) and HB-Absol (12.5) and b) the same as C-Rel (11.3) and HB-Rel (10.7). RPE-Legs during TM-Rel was a) lower (P less than 0.05) than C-Absol and HB-Absol and b) the same as C-Rel and HB-Rel. RPE-Chest a) did not differ between TM-Rel and C-Absol or HB-Absol and b) was lower (P less than 0.05) for C-Rel and HB-Rel than TM-Rel. RPE-Arms was higher (P less than 0.05) for C-Absol, HB-Absol, and HB-Rel than TM-Rel but did not differ between TM-Rel and C-Rel. Oxygen uptake, heart rate, and ventilation during TM-Rel were a) the same as C-Absol and HB-Absol and b) higher (P less than 0.05) than C-Rel and HB-Rel. Perceptually based cross-modal prescription of exercise intensity using a psychophysical estimation method is valid provided that the physiological reference is the relative, not the absolute, VO2.

A multicenter study of the prevalence and susceptibility patterns of isolates of Streptococcus pneumoniae with reduced susceptibility to penicillin G in Louisiana.

Because of increasing reports of multiple-antibiotic-resistant strains of Streptococcus pneumoniae and associated clinical failures, this study was performed to determine the prevalence of multiresistance among strains from nine Louisiana medical centers. Using a National Committee for Laboratory Standards broth microdilution method, 481 strains were tested. Of these, 70% were penicillin-susceptible (PS), 23% had intermediate minimum inhibitory concentration values to penicillin (I), and 7% were fully resistant to penicillin (PR). The isolation rates (15% to 40% for I strains and 0% to 33% for PR strains) at the various medical centers varied appreciably. The prevalence of penicillin resistance was highest among upper respiratory isolates, while cross-resistance to other antimicrobials varied. The least cross-resistance was noted among PS strains. However, strains with reduced penicillin susceptibility had high levels of cross-resistance. Among I strains, the prevalence of cross-resistance (%) was noted for amoxicillin/clavulanate (6%), cefuroxime (71%), cefaclor (91%), ceftriaxone (13%), cefotaxime (34%), erythromycin (67%), azithromycin (32%), and clarithromycin (32%). For PR strains, the prevalence of cross-resistance was 97% for amoxicillin/clavulanate, cefuroxime, and cefaclor; 67% for ceftriaxone and erythromycin; 89% for cefotaxime; and 69% for azithromycin and clarithromycin. These data emphasize the high prevalence of multiple-antimicrobial-resistance among strains of S pneumoniae with reduced penicillin susceptibility in this geographic area.

Reducing the cost of health care capital.

Although one may ask four financial experts their opinion on the future of the hospital capital market and receive five answers, the blatant need for financial strategic planning is evident. Clearly, the hospital or system with sound financial management will be better positioned to gain and/or maintain an edge in the competitive environment of the health care sector. The trends of the future include hospitals attempting to: Maximize the efficiency of invested capital. Use the expertise of Board members. Use alternative capital sources. Maximize rate of return on investments. Increase productivity. Adjust to changes in reimbursements. Restructure to use optimal financing for capital needs, i.e., using short-term to build up debt capacity if long-term financing is needed in the future. Take advantage of arbitrage (obtain capital and reinvest it until the funds are needed). Delay actual underwriting until funds are to be used. Better management of accounts receivable and accounts payable to avoid short-term financing for cash flow shortfalls. Use for-profit subsidiaries to obtain venture capital by issuing stock. Use product line management. Use leasing to obtain balance sheet advantages. These trends indicate a need for hospital executives to possess a thorough understanding of the capital formation process. In essence, the bottom line is that the short-term viability and long-term survival of a health care organization will greatly depend on the financial expertise of its decision-makers.

Effects of overnight refrigeration on the microscopic evaluation of sputum.

Microscopic evaluation of sputum permits selection of specimens suitable for culture, assessment of likely pathogens, and the best interpretation of culture results. We prospectively evaluated 50 sputum specimens which were promptly submitted to our clinical laboratory; smears and cultures were performed both immediately and after 20 h of refrigeration. Specimens were grouped according to the numbers of squamous epithelial cells and neutrophils per low-power field present on coded Gram-stained smears. The numbers of bacteria in five oil immersion fields were used to characterize smears for predominant, mixed, or scanty forms. After refrigeration, only three specimens changed group from a definite loss of squamous epithelial cells, and only two changed group from a definite loss of neutrophils. Based on cellular composition, the majority of samples would have been processed identically both before and after refrigeration. In contrast, organism forms detected on smears and their relative quantities were dramatically altered after refrigeration. A predominant smear form was gained in 11 and lost in 8 refrigerated specimens. The frequent changes on smears observed overall resulted from both increases and decreases in numbers of bacteria and yeasts. The majority of sputum culture results were insignificantly affected by the refrigeration of specimens. We conclude that 20 h of refrigeration renders sputum useless for the microscopic evaluation of potential pathogens and the subsequent interpretation of culture results. However, overnight refrigeration does not affect the determination from smears of sputum suitability for culture based on cellular composition.

Drug-resistant Streptococcus pneumoniae.

Streptococcus pneumoniae remains a major cause of infection in both children and adults, annually resulting in significant morbidity and mortality. The past two decades have seen an alarming worldwide increase in the incidence of drug-resistant S. pneumoniae (DRSP). DRSP is now common throughout the United States, and physicians are questioning how best to approach this epidemic. With the introduction of a number of newer antimicrobial agents, the potential for improved preventive measures, and a better understanding of DRSP, the approach to the management of DRSP infections may change greatly in the next few years. In this article we will review the development of DRSP, identify populations at increased risk of exposure to DRSP, address what approaches might be used to limit its spread, and suggest initial empirical therapy when treating patients with pneumonia due to DRSP.

Tissue distribution of avidin and streptavidin injected to mice. Effect of avidin carbohydrate, streptavidin truncation and exogenous biotin.

Radioionated avidin and streptavidin were characterized for their biodistribution and tissue association in Balb/c mice, in comparison to their interaction with cells in vitro. Binding of avidin to spleen and bone-marrow cells in vitro was up to 20-fold higher than that of streptavidin, but when tested in vivo avidin clearance from blood and tissues was considerably faster than that of streptavidin. Levels of avidin at 24 h after an intravenous injection were below 1% (of the injected dose/mass tissue) in most organs. Non-glycosylated avidin was similar in its biodistribution to native avidin. Native streptavidin exhibited higher and prolonged tissue association with 5-10% levels in lung, liver, spleen, kidney and blood, whereas its truncated form showed low tissue levels (1-3%) but a remarkably high affinity to the kidney (80%). Exogenous biotin did not affect streptavidin distribution in vivo but caused a 2-7-fold increase in the retention of avidin (but not non-glycodylated avidin) in some of the organs.

Hepatitis B vaccine in healthy hospital employees.

A low rate of seroconversion to hepatitis B vaccine is reported. This occurred in healthy hospital employees from two separate institutions. A total of 236 individuals were evaluated in this study and only 53% or 124 persons developed protective levels of antibody to hepatitis B surface antigen following a complete vaccine series. In one hospital, 30% of the vaccine recipients developed antibody but not to a protective level. Employees who received the entire series in the arm or in the arm and buttock (mixed) had a significantly greater number of responders than employees who received the entire series in the buttock (P less than .05). Recipients aged 50 to 59 years had a significantly lower response rate to the vaccine (P less than .05). There was no correlation with the vaccinee's sex or the timing of the second injection. Vaccine was noted to have frozen in one hospital and accounted for some loss of antigenicity. This failure to respond to the vaccine has necessitated the use of booster injections of vaccine and continued antibody monitoring.

Wound infection following cesarean section.

To investigate a high incidence of wound infections occurring in patients following cesarean section at a 650 bed charity hospital in Louisiana, a bacteriologic investigation was carried out. In this study, cultures were made at multiple sites prior to operation. An attempt was made to identify those bacteria that were predominately responsible for wound infection and their source, whether from the patient herself or from a nosocomial origin. The patients were divided into three groups depending on the degree of postoperative morbidity that followed. The bacterial flora in each group was relatively the same. Other factors were more significant in predicting those patients in whom postoperative morbidity occurred.