Biomedical subjects

W J Brown

Publications and source records attributed to W J Brown.

At least 37 records · Page 2Linked to original sources

PubMed2000

Relationships between body mass index and well-being in young Australian women.

OBJECTIVE: To explore relationships between body mass index (BMI, kg/m2) and indicators of health and well-being in young Australian women. DESIGN: Population based cohort study--baseline cross sectional data. SUBJECTS: 14,779 women aged 18-23 who participated in the baseline survey of the Australian Longitudinal Study on Women's Health in 1996. MEASUREMENTS: Self-reported height, weight, medical conditions, symptoms and SF-36. RESULTS: The majority of women (68%) had a BMI in the range 18.5- <25; 12% had a BMI <18.5; 14% had a BMI in the range 25- <30 and 6% had a BMI > or =30. After adjustment for area of residence, age, education, smoking and exercise, women in the highest BMI category (> or =30) were more likely to report hypertension, asthma, headaches, back pain, sleeping difficulties, irregular periods, and more visits to their medical practitioner. They were also more likely to have given birth at least once, and less likely to report 'low iron'. Women with low BMI (<18.5) were more likely to report irregular periods and 'low iron'. Mean scores on the SF-36 sub-scales for physical functioning, general health and vitality were highest for women with BMI in the range 18.5-25. CONCLUSION: Acknowledging the limits of the cross-sectional nature of the data, the results show that the deleterious effects of overweight can be seen at a comparatively young age, and that BMI <25 is associated with fewer indicators of morbidity in young women. However, as BMI <18.5 is associated with low iron and irregular periods, care should be taken when developing strategies to prevent overweight in young women, not to encourage women with healthy weight to strive for a lower BMI.

Adolescent↗

PubMed2000

A secondary structure motif predictive of protein localization to the chlamydial inclusion membrane.

Chlamydiae are obligate intracellular pathogens that spend their entire growth phase sequestered in a membrane-bound vacuole called an inclusion. A set of chlamydial proteins, labelled Inc proteins, has been identified in the inclusion membrane (IM). The predicted IncA, IncB and IncC amino acid sequences share very limited similarity, but a common hydrophobicity motif is present within each Inc protein. In an effort to identify a relatively complete catalogue of Chlamydia trachomatis proteins present in the IM of infected cells, we have screened the genome for open reading frames encoding this structural motif. Hydropathy plot analysis was used to screen each translated open reading frame in the C. trachomatis genome database. Forty-six candidate IM proteins (C-lncs) that satisfied the criteria of containing a bilobed hydrophobic domain of at least 50 amino acids were identified. The genome of Chlamydia pneumoniae encodes a larger collection of C-lnc proteins, and only approximately half of the C-lncs are encoded within both genomes. In order to confirm the hydropathy plot screening method as a valid predictor of C-lncs, antisera and/or monoclonal antibodies were prepared against six of the C. trachomatis C-lncs. Immunofluorescence microscopy of C. trachomatis-infected cells probed with these antibodies showed that five out of six C-lncs are present in the chlamydial IM. Antisera were also produced against C. pneumoniae p186, a protein sharing identity with Chlamydia psittaci lncA and carrying a similar bilobed hydrophobic domain. These antisera labelled the inclusion membrane in C. pneumoniae infected cells, confirming that proteins sharing the unique secondary structural characteristic also localize to the inclusion membrane of C. pneumoniae. Sera from patients with high-titre antibodies to C. trachomatis were examined for reactivity with each tested C-lnc protein. Three out of six tested C-lncs were recognized by a majority of these patient sera. Collectively, these studies identify and characterize novel proteins localized to the chlamydial IM and demonstrate the existence of a potential secondary structural targeting motif for localization of chlamydial proteins to this unique intracellular environment.

Amino Acid Sequence↗

PubMed2000

Leisure time physical activity in Australian women: relationship with well being and symptoms.

This paper explores the association between moderate levels of physical activity (PA) and health benefits in well being and symptoms such as tiredness, back pain, and constipation. Participants in the Australian Longitudinal Study on Women's Health, 14,502 young women (ages 18-23 years), 13,609 middle-age women (45-50 years), and 11,421 older women (ages 70-75 years), answered questions about vigorous and less vigorous exercise (used to determine a physical activity score), well being (SF-36), symptoms, and medical conditions. There were significant associations between the PA score and SF-36 in each cohort. Odds ratios (OR) for a range of symptoms and conditions were lower for women who reported low to moderate activity than for sedentary women, for example, for young women or for constipation = 0.76 (CI, 0.65-0.89), for middle-age women or for tiredness = 0.70 (0.63-0.78). There was no threshold of PA at which health benefits increased significantly. Although cross-sectional, the findings suggest that low-to-moderate levels of exercise are associated with a range of health benefits for women of all ages. These preliminary findings will be followed up during the longitudinal study.

Adolescent↗

PubMed2000

Yersinia enterocolitica infection in children.

BACKGROUND: Yersinia enterocolitica can cause illness ranging from self-limited enteritis to life-threatening systemic infection. The present study was undertaken to review the epidemiology, clinical manifestations, complications and outcome of Y. enterocolitica enteritis in children seen at a large children's hospital. METHODS: The project consisted of a retrospective chart review of medical and microbiologic records of all children with stool cultures positive for Y. enterocolitica during a 7-year period. RESULTS: The review included 142 patients with Y. enterocolitica enteritis. Patients' ages ranged from 18 days to 12 years, and the majority (85%) were younger than 1 year. Most patients presented during November, December and January. History of exposure to chitterlings (raw pork intestines) at home was elicited in 25 of 30 cases. Y. enterocolitica accounted for 12.6% (142 of 1,120) of all bacterial intestinal pathogens isolated during the study period. Blood cultures were positive in 7(9%) of 78 patients; 6 were younger than 1 year and one 12-year-old had sickle cell disease. Of 132 isolates tested all were susceptible to trimethoprim-sulfamethoxazole, tobramycin and gentamicin; the majority were susceptible to cefotaxime (99%), ceftazidime (89%) and cefuroxime (88%). All bacteremic patients responded to cefotaxime treatment. Follow-up evaluation of 40 ambulatory patients revealed no difference in clinical improvement between those treated with oral trimethoprim-sulfamethoxazole (17 of 23) and those who were not treated (8 of 17) (P = 0.1). CONCLUSION: Y. enterocolitica is an important cause of enteritis in our young patient population during the winter holidays. Exposure of infants to chitterlings appears to be a risk factor. Infants younger than 3 months are at increased risk for bacteremia. Cefotaxime is effective in the treatment of Y. enterocolitica bacteremia; however, the role of oral antibiotics in the management of enteritis needs further evaluation.

Adolescent↗

PubMed2000

Patterns of alcohol consumption in young Australian women: socio-demographic factors, health-related behaviours and physical health.

OBJECTIVE: To determine which socio-demographic factors, health-related behaviours and physical health conditions are associated with non-drinking, binge drinking and hazardous/harmful drinking in young Australian women. METHODS: Cross-sectional data were obtained from the baseline survey of 14,762 young women (aged 18-23 years) enrolled in the Women's Health Australia study in 1996. Associations between a range of drinking patterns and socio-demographic factors, health-related behaviours and health conditions were examined. RESULTS: Half the women were 'low intake' drinkers, a third 'rarely drank' and 9% were non-drinkers; however, 70% reported binge drinking with one-quarter of the binge drinkers doing so at least weekly. Non-drinkers were more likely than drinkers to be married, pregnant, non-smokers, born in non-English speaking countries, to live in the Northern Territory, and to have lower levels of education, employment, and private health insurance. 'Low intake/binge weekly' drinkers (12%) and 'hazardous/harmful' drinkers (5%) were more likely than 'low risk' drinkers to be unmarried; to live in shared accommodation, alone or with their parents; to live in rural or remote areas; to have ever had any sexually transmitted infection; to be current smokers or ex-smokers and to have used unhealthy weight-control practices. CONCLUSIONS: The results confirm findings from other countries about the importance of social conditions as determinants of alcohol consumption by young women. IMPLICATIONS: Health promotion to reduce young women's alcohol consumption needs to be carefully targeted to take account of their demographies, living environments and beliefs.

Adolescent↗

PubMed2000

Comparison of estimates of population levels of physical activity using two measures.

OBJECTIVE: To compare estimates of population levels of 'adequate activity' for health benefit in different age and sex groups using two different measures--kilocalories (kcals) and Mets.mins. METHODS: 10,464 mid-age women (47-52 years) from the second survey of the Australian Longitudinal Study on Women's Health (ALSWH, 1998) and 2,500 men and women (18-75 years) from the 1997 Active Australia national survey, answered questions about physical activity. Kcals and Mets.mins were calculated from self-reported time spent in walking, moderate and vigorous activity, and self-reported body weight. 'Adequate activity' was defined as a minimum of 800 kcals or 600 Mets.mins. RESULTS: There were differences in the estimates of 'adequate activity' using the two methods among women participants in both surveys, but not among the male participants in the Active Australia survey. A significant proportion of the women in both surveys (6.4% of the ALSWH women and 8.5% of the Active Australia women, mean weight 60 kg) were classified as 'inactive' when the kcals method was used despite reporting levels of activity commensurate with good health. Fewer than 1% (mean weight 105 kg) were classified as 'active' using kcals when reporting lower than recommended levels of activity. Agreement between the two methods was better among men; only 3% were misclassified because of low or very high weight. CONCLUSIONS: The Mets.mins method of estimating 'adequate' activity assesses physical activity independently of body weight and is recommended for use in future population surveys, as it is less likely to under-estimate the prevalence of physical activity in women. IMPLICATIONS: Women and men aged 45-59 and women aged > 60 should be the target of specific health promotion strategies to increase population levels of physical activity.

Adolescent↗

PubMed2000

The Anti Cancer Council of Victoria FFQ: relative validity of nutrient intakes compared with weighed food records in young to middle-aged women in a study of iron supplementation.

OBJECTIVE: To assess the validity of the Anti Cancer Council of Victoria food frequency questionnaire (ACCVFFQ) relative to seven-day weighed food records (WFRs) in 63 women of child-bearing age. METHOD: 63 women completed WFRs to assess iron intake as part of a study on iron deficiency. These women also completed the ACCVFFQ. Nutrient intakes were computed independently for the WFRs and FFQs. Intakes were compared as group means, by correlation and by quintile classification, adjusting for day-to-day variation in intakes, and for energy intake. Individual differences in results were also examined. RESULTS: The strongest associations between WFR and FFQ results were energy-adjusted, log-transformed and adjusted for day-to-day variability in intake. Correlation coefficients ranged from 0.28 for vitamin A to 0.78 for carbohydrate. Mean intakes from the WFRs and FFQs were within +/- 20% for 21 of 27 nutrients. Poor agreement between FFQs and WFRs for retinol intake was due to the inclusion of liver in two WFRs, an item which is not included in the FFQ. CONCLUSION: The ACCVFFQ performs as well as other FFQs for which validation data are available. The relatively poor measurement of retinol is consistent with other data, and with the limited number of foods in which this nutrient is abundant. IMPLICATIONS: The availability of an optically scannable valid instrument for assessing dietary intake will facilitate epidemiological studies of diet and disease, an area of current research priority.

Adolescent↗

PubMed2000

Identification of an antigen localized to an apparent septum within dividing chlamydiae.

The process of chlamydial cell division has not been thoroughly investigated. The lack of detectable peptidoglycan and the absence of an FtsZ homolog within chlamydiae suggest an unusual mechanism for the division process. Our laboratory has identified an antigen (SEP antigen) localized to a ring-like structure at the apparent septum within dividing chlamydial reticulate bodies (RB). Antisera directed against SEP show similar patterns of antigen distribution in Chlamydia trachomatis and Chlamydia psittaci RB. In contrast to localization in RB, SEP in elementary bodies appears diffuse and irregular, suggesting that the distribution of the antigen is developmental-stage specific. Treatment of chlamydiae with inhibitors of peptidoglycan synthesis or culture of chlamydiae in medium lacking tryptophan leads to the formation of nondividing, aberrant RB. Staining of aberrant RB with anti-SEP reveals a marked redistribution of the antigen. Within C. trachomatis-infected cells, ampicillin treatment leads to high levels of SEP accumulation at the periphery of aberrant RB, while in C. psittaci, treatment causes SEP to localize to distinct punctate sites within the bacteria. Aberrancy produced via tryptophan depletion results in a different pattern of SEP distribution. In either case, the reversal of aberrant formation results in the production of normal RB and a redistribution of SEP to the apparent plane of bacterial division. Collectively these studies identify a unique chlamydial-genus-common and developmental-stage-specific antigen that may be associated with RB division.

Animals↗

PubMed1999

Stimulation of Golgi membrane tubulation and retrograde trafficking to the ER by phospholipase A(2) activating protein (PLAP) peptide.

Recent pharmacological studies using specific antagonists of phospholipase A(2) (PLA(2)) activity have suggested that the formation of Golgi membrane tubules, 60-80 nm in diameter and up to several microns long, both in vivo and in a cell-free cytosol-dependent reconstitution system, requires the activity of a cytoplasmic Ca(2+)-independent PLA(2). We confirm and extend these studies by demonstrating that the stimulators of PLA(2), melittin and PLA(2) activating protein peptide (PLAPp), enhance cytosol-dependent Golgi membrane tubulation. Starting with preparations of bovine brain cytosol (BBC), or a fraction of BBC that is highly enriched in tubulation activity, called the gel filtration (GF) fraction, that are at subsaturating concentrations for inducing tubulation in vitro, we found that increasing concentrations of melittin or PLAPp produced a linear and saturable stimulation of Golgi membrane tubulation. This stimulation was inhibited by cytosolic PLA(2) antagonists, including the Ca(2+)-independent PLA(2)-specific antagonist, bromoenol lactone. The stimulatory effect of PLAPp, and its inhibition by PLA(2) antagonists, was reproduced using a permeabilized cell system, which reconstitutes both cytosol-dependent Golgi membrane tubulation and retrograde trafficking to the endoplasmic reticulum (ER). Taken together, these results are consistent with the idea that cytosolic PLA(2) activity is involved in the formation of Golgi membrane tubules, which can serve as trafficking intermediates in Golgi-to-ER retrograde movement.

Animals↗

PubMed1999

Clofibrate inhibits membrane trafficking to the Golgi complex and induces its retrograde movement to the endoplasmic reticulum.

Insights into the function of the Golgi complex have been provided by experiments performed with various inhibitors of membrane trafficking, such as the macrocyclic lactone brefeldin A (BFA), a compound that inhibits constitutive secretion, prevents the formation of coatomer-coated transport vesicles, and stimulates the retrograde movement of Golgi resident enzymes back to the ER. We show here that the structurally unrelated compound clofibrate, a peroxisome proliferator (PP) and hypolipidemic agent, also reversibly disrupts the morphological and functional integrity of the Golgi complex in a manner similar to BFA. In the presence of clofibrate, the forward transport of newly synthesized secretory proteins from the ER to the Golgi is dramatically inhibited. Moreover, clofibrate causes Golgi membranes to travel rapidly in a microtubule-dependent manner back to the ER, forming a hybrid ER-Golgi tubulovesicular membrane network. These affects appear to be independent of clofibrate's ability to stimulate the PP-activated receptor (PPAR) alpha pathway because other PPAR stimulators (DEHP, WY-14643) did not alter the Golgi complex or induce retrograde trafficking. These data suggest that PPAR alpha-independent, clofibrate-sensitive proteins participate in regulating Golgi-to-ER retrograde membrane transport, and, equally importantly, that clofibrate may be used as a pharmacological tool for investigating Golgi membrane dynamics.

Animals↗

PubMed1999

Tyranny of distance? The health of mid-age women living in five geographical areas of Australia.

Over 14,000 women aged 45-50 are participating in the Australian Longitudinal Study on Women's Health, which is designed to track the health of Australian women for 20 years, and to understand lifestyle and healthcare factors that influence women's health. The study deliberately overrepresents women from rural and remote areas. This analysis of baseline data from the study compares the responses of women living in urban areas (capital city, other metropolitan), large rural centres, small rural centres, other rural areas and remote areas (remote centres, other remote areas) of Australia. The data show that while women in this age group who live in rural and remote areas have similar levels of self-rated health, they have significantly fewer visits to general practitioners and specialists (P < 0.001) and more visits to alternative healthcare providers than women living in urban areas. Rural and remote area women were also more likely to undergo gynaecological surgery than women living in urban areas (P < 0.001). Other results suggest that being overweight is more common among women from rural and remote areas, and that these women also report lower levels of stress than women from urban areas (P < 0.001). Further follow up will allow any divergence in health and healthcare equity to be explored as these women get older.

Australia↗

PubMed1999

Women's Health Australia: on the progress of the main cohort studies.

More than 41,000 women aged 18-23, 45-50, and 70-75 years in 1996 are participating in the Australian Longitudinal Study on Women's Health (Women's Health Australia). Baseline surveys were conducted for all three cohorts in 1996, and the first follow-up survey of the mid-age group in 1998 has achieved a response rate exceeding 90%. The main findings so far reflect the large differences in the life experiences of the three cohorts. The young women report high levels of stress. The physical and mental health of those with young children is worse than for those without children, but confounding by sociodemographic characteristics may account for the differences. Two thirds of young women in the healthy weight or underweight range would like to weigh less, and early onset of dieting is associated with poorer physical and mental health. Most of the women in the mid-age group have multiple roles--in paid work, home duties, and caring for children and other dependents. The potential of the study to investigate the long-term impact of such busy lives on health outcomes is considerable. At this stage, the main health issues for these women relate to tiredness, weight gain, and menopause. The older cohort presents a picture of positive aging. These women are heavier users of health services than the mid-age and younger women, and they are also more satisfied with these services. Although their physical health is poorer, their mental health is better, and they report less stress than women in the other two cohorts. The follow-up survey of this group, planned for 1999, will focus on the coping strategies used by these women. An overall goal of the project is to understand the interactions among social roles, life events, and women's health in order to provide a basis for improved health policies and services. Analysis of these interactions, which relies on both quantitative and qualitative data, poses many challenges that will be addressed as the longitudinal data become available.

Adult↗

PubMed1999

Phospholipase A(2) antagonists inhibit nocodazole-induced Golgi ministack formation: evidence of an ER intermediate and constitutive cycling.

Evidence has been presented both for and against obligate retrograde movement of resident Golgi proteins through the endoplasmic reticulum (ER) during nocodazole-induced Golgi ministack formation. Here, we studied the nocodazole-induced formation of ministacks using phospholipase A(2) (PLA(2)) antagonists, which have been shown previously to inhibit brefeldin A-stimulated Golgi-to-ER retrograde transport. Examination of clone 9 rat hepatocytes by immunofluorescence and immunoelectron microscopy revealed that a subset of PLA(2) antagonists prevented nocodazole-induced ministack formation by inhibiting two different trafficking pathways for resident Golgi enzymes; at 25 microM, retrograde Golgi-to-ER transport was inhibited, whereas at 5 microM, Golgi-to-ER trafficking was permitted, but resident Golgi enzymes accumulated in the ER. Moreover, resident Golgi enzymes gradually redistributed from the juxtanuclear Golgi or Golgi ministacks to the ER in cells treated with these PLA(2) antagonists alone. Not only was ER-to-Golgi transport of resident Golgi enzymes inhibited in cells treated with these PLA(2) antagonists, but transport of the vesicular stomatitis virus G protein out of the ER was also prevented. These results support a model of obligate retrograde recycling of Golgi resident enzymes during nocodazole-induced ministack formation and provide additional evidence that resident Golgi enzymes slowly and constitutively cycle between the Golgi and ER.

Animals↗

PubMed1999

Membrane tubule-mediated reassembly and maintenance of the Golgi complex is disrupted by phospholipase A2 antagonists.

Although membrane tubules can be found extending from, and associated with, the Golgi complex of eukaryotic cells, their physiological function has remained unclear. To gain insight into the biological significance of membrane tubules, we have developed methods for selectively preventing their formation. We show here that a broad range of phospholipase A2 (PLA2) antagonists not only arrest membrane tubule-mediated events that occur late in the assembly of the Golgi complex but also perturb its normal steady-state tubulovesicular architecture by inducing a reversible fragmentation into separate "mini-stacks." In addition, we show that these same compounds prevent the formation of membrane tubules from Golgi stacks in an in vitro reconstitution system. This in vitro assay was further used to demonstrate that the relevant PLA2 activity originates from the cytoplasm. Taken together, these results demonstrate that Golgi membrane tubules, sensitive to potent and selective PLA2 antagonists, mediate both late events in the reassembly of the Golgi complex and the dynamic maintenance of its steady-state architecture. In addition, they implicate a role for cytoplasmic PLA2 enzymes in mediating these membrane trafficking events.

Aminobenzoates↗

PubMed1999

Synergistic effect of hyperoxia and immunoglobulin A on mucosal barrier defense.

BACKGROUND: Hyperoxia has been reported to be protective against gut-derived sepsis. Although secretory immunoglobulin A (IgA) is primarily responsible for humoral defense of mucosal surfaces, a potential synergistic effect with hyperoxia is unknown. An asanguineous cell monolayer system was used to study these aspects in vitro. METHODS: MDCK cells were grown as polarized monolayers in a two-chamber culture system. Apical chambers were inoculated with 10(8) Escherichia coli M14 with or without polyclonal IgA and incubated in a 21 or 95% O2 environment. Basal medium was sampled at 90 and 180 minutes for bacterial translocation. In a second experiment, MDCK cells were lysed at 90 minutes and intracellular bacteria were quantitated. RESULTS: Bacterial translocation was decreased versus normoxia by the treatment groups IgA without hyperoxia or IgA with hyperoxia at 90 minutes. Bacterial internalization at 90 minutes was reduced to the greatest extent by the combined effects of hyperoxia and IgA. Translocation data at 180 minutes confirmed the additional protective effect of hyperoxia with IgA. CONCLUSION: Hyperoxia exerts a significant protective effect on barrier function independent of enhanced leukocyte function. Hyperoxia has an added effect to the mucosal defense provided by IgA.

Aerobiosis↗

PubMed1999

Synergistic effects of Candida and Escherichia coli on gut barrier function.

BACKGROUND: Disruption of the indigenous gut microflora with overgrowth of gram-negative bacteria and Candida species is common in the critically ill patient. These organisms readily translocate in vitro, which may cause septic complications and organ failure. A synergistic effect between Escherichia coli and C. albicans in polymicrobial infections has been demonstrated. An interaction between these organisms at the mucosal barrier is unknown. METHODS: Ca(CO2) monolayers were grown to confluence in a two compartment culture system. E. coli and C. albicans or E. coli alone were added to the apical chambers. Secretory immunoglobulin A was added to half of the apical chambers as well. Cell cultures were incubated for a total of 240 minutes. Basal media were sampled at timed intervals for quantitative culture. Monolayer integrity was confirmed by serial measurement of transepithelial electrical resistance. RESULTS: Secretory immunoglobulin A decreased bacterial translocation across Ca(CO2) monolayers challenged with E. coli alone. Transepithelial passage of E. coli was significantly increased by coculture of bacteria with C. albicans. Augmentation of bacterial translocation by Candida occurred even in the presence of secretory immunoglobulin A. CONCLUSIONS: Candida colonization of the GI tract may impair mucosal barrier defense against gram-negative bacteria. The clinical role of gut antifungal prophylaxis in protecting against gut derived gram-negative sepsis is speculative.

Bacterial Translocation↗

PubMed1999

Leaking urine in Australian women: prevalence and associated conditions.

The paper aims to (1) assess the prevalence of leaking urine and to (2) explore associations between leaking urine and a variety of other symptoms, conditions, surgical procedures and life events in three large cohorts of Australian women, who are participants in the Australian Longitudinal Study on Women's Health. Young women aged 18-23 (N = 14,000), mid-age women, 45-50 (N = 13,738) and older women, 70-75 (N = 12,417), were recruited randomly from the national HIC/Medicare database. Leaking urine was reported by approximately one in eight young women [estimated prevalence 12.8% (95% CI: 12.2-13.3)] and one in three mid-age women [36.1% (CI: 35.2-37.0)] and older women [35.0% (CI: 34.1-35.9)]. Leaking urine was significantly associated with parity, conditions which increase the pressure on the pelvic floor such as constipation and obesity, past gynecological surgery and conditions which can impact on bladder control. The study showed that fewer than half the women had sought help for the problem and that younger women were less likely to be satisfied with the help available for this problem. Strategies for continence promotion, including opportunistic raising of the issue at the time of cervical screening and pregnancy care are suggested, so that the health and social outcomes of untreated chronic incontinence in women might be improved.

Adult↗

PubMed1999

Evaluation of Acinetobacter baumannii infection and colonization, and antimicrobial treatment patterns in an urban teaching hospital.

In 1990 there was a sudden increase in the incidence of colonization and infection due to Acinetobacter baumannii (AB) in our intensive care units (ICUs). The isolates were multiply resistant to beta-lactam and aminoglycoside antibiotics, but remained susceptible to imipenem, amikacin, and ampicillin-sulbactam. We examined the frequency of infection and colonization with AB and the effects of increased imipenem and amikacin therapy on Pseudomonas aeruginosa. We also used disease-matched controls to determine the clinical and financial impacts of treating colonization. All patients with at least one AB isolate from January-December 1992 were identified retrospectively and classified as infected or colonized based on published Centers for Disease Control criteria; the control group was selected from a computerized medical records data base matching primary diagnostic codes (102 patients both groups). The 102 patients yielded 140 isolates, 124 resistant AB and 16 sensitive AB. Thirty three patients were infected, 69 colonized. Mortality correlated with APACHE II scores. Patients acquired the organism approximately 2 weeks after admission; they had a mean ICU stay of 27.35 days, compared with 5.53 days for controls. Patients with positive AB cultures required significantly more use of ventilators than those with negative AB cultures. They also had significantly longer hospital stay, more bed transfers, greater duration and number of antibiotics, and higher hospital and pharmacy charges. Unnecessary treatment for colonization with either imipenem or amikacin resulted in a substantial decrease of P. aeruginosa susceptibility to each agent. The financial impact of treating colonization was significant and is a potential area for cost avoidance. Our results emphasize the need to extubate and move patients to non-ICU beds as soon as possible to decrease the risk of nosocomial infection. It also highlights the need to avoid treating colonization, thus avoiding unnecessary antibiotic therapy.

Acinetobacter↗