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Biomedical subjects

R A Weinstein

Publications and source records attributed to R A Weinstein.

At least 109 records · Page 6Linked to original sources
PubMed1987

Patients' endogenous flora as the source of "nosocomial" Enterobacter in cardiac surgery.

We prospectively studied Enterobacter colonization in cardiac surgery patients receiving cefazolin prophylaxis. Fifty-eight (67%) of 87 patients became colonized, 28 by the time of admission to a Cardiac Surgery Intensive Care Unit. Enterobacter cloacae was four times more prevalent than Enterobacter aerogenes. We found increased Enterobacter colonization, after prophylaxis, in 45% of surgery patients. None of 25 control patients, who underwent coronary angioplasty and received no antibiotic prophylaxis, showed increased colonization (P = .001). Both groups had similar baseline rates of Enterobacter carriage. Typing showed 50 distinct strains of E. cloacae and 11 of E. aerogenes; 25% of patients carried greater than or equal to 2 strains simultaneously. In the nine cases of horizontal transmission, source patients were intubated for greater than or equal to 5 days and had heavy throat carriage of Enterobacter. No environmental sources of transmission were found. Clinical Enterobacter infection developed in 12 patients; at least nine of these were infected with a strain that had been isolated by surveillance culture. We conclude that Enterobacter, part of the patients' endogenous flora, becomes an important pathogen when amplified by prophylactic antibiotics and is less often transmitted horizontally.

Aged↗
PubMed1987

In vitro susceptibility of nosocomial Pseudomonas aeruginosa, enterobacteriaceae, and staphylococci to ciprofloxacin and ten other broad-spectrum antibiotics.

We determined microdilution minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) for ciprofloxacin and 10 beta-lactam and aminoglycoside antibiotics against 329 unique nosocomial isolates of Pseudomonas aeruginosa, citrobacter, enterobacter, serratia, and staphylococci. All were susceptible to ciprofloxacin, including 109 aminoglycoside-resistant gram-negative bacilli and 59 oxacillin-resistant staphylococci. Ciprofloxacin was generally 2-4 fold less active against aminoglycoside-resistant isolates than against their aminoglycoside-susceptible counterparts.

Aminoglycosides↗
PubMed1986

Extended use of disposable pressure transducers. A bacteriologic evaluation.

In a prospective randomized study, contamination rates of disposable pressure transducers changed every two days (n = 81) were compared with those changed at four (n = 26) or eight days (n = 50); the mean daily incidence of contamination was 3% for each group. After four days of use, the cumulative prevalences of contamination were similar. However, after eight days, the cumulative prevalence was significantly higher in transducers used without change (6.9%) than in those changed every two days (2.9%). Gram-negative bacilli were present in 63% of contaminated transducers; over half were from the patients' own flora. The only definite transducer-related bacteremia occurred on a day of initial contamination and should have been unaffected by the interval of change. Routine use of disposable transducers can be safely extended to four days, even in a busy intensive care unit.

Bacteria↗
PubMed1986

Radiation-induced thyroid and other head and neck tumors: occurrence of multiple tumors and analysis of risk factors.

In 2561 patients who received conventional external radiation treatment before age 15 yr for benign conditions of the head, neck, and upper thoracic area, we found an increase in the number of salivary gland tumors and benign neural tumors of the head and neck area. To determine whether patients who developed these relatively uncommon tumors were more susceptible to the long term effects of radiation, we analyzed how frequently these patients also developed benign and malignant thyroid neoplasms. Compared to the remainder of the irradiated population, the patients with salivary and neural tumors had an increased frequency of thyroid disease (19.4% vs. 11.2% for thyroid cancer and 52.4% vs. 39.9% for all thyroid nodules). Various risk factors were studied to determine whether they were related to the eventual occurrence of thyroid disease. Higher doses, being female, and lower ages at time of treatment were associated with increased risk. However, these factors did not fully explain the differences in the frequency of coexisting tumors, suggesting that additional factors, such as radiation sensitivity, may account for the increased risk.

Age Factors↗
PubMed1985

Transfusion-associated acquired immunodeficiency syndrome. Evidence for persistent infection in blood donors.

To investigate whether infection with human T-cell lymphotropic virus/lymphadenopathy-associated virus (HTLV-III/LAV) may be persistent in asymptomatic persons and to correlate infection with seropositivity, we performed virologic and serologic studies in 25 of 30 persons who were identified as being at high risk for the acquired immunodeficiency syndrome (AIDS) and who had donated blood to patients who later contracted transfusion-associated AIDS. High-risk donors were those who belonged to a high-risk population, had AIDS or a closely related condition, or had a low ratio of helper to suppressor T lymphocytes. We performed similar studies in 6 of the 24 patients with AIDS who had received donations from this group. HTLV-III/LAV was isolated from 22 of the 25 donors, between 12 and 52 months (mean, 28) after they had donated blood, and from all 6 recipients, between 14 and 37 months (mean, 26) after they had received blood. Of the 22 virus-positive donors, 2 have contracted AIDS, 5 have generalized lymphadenopathy, and 15 (68 per cent) remain asymptomatic. Antibodies to HTLV-III/LAV were detectable by the enzyme-linked immunosorbent assay in serum samples obtained from each person at the time the virus was isolated. We conclude that infection with HTLV-III/LAV may be persistent and asymptomatic for years. This demonstration that viremic patients may be asymptomatic supports the use of serologic screening of donated blood to supplement current procedures for the prevention of transfusion-associated AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1985

False localization of site of endocarditis by cardiac catheterization with quantitative cultures.

The authors present a patient with relapsing Pseudomonas aeruginosa endocarditis in whom cardiac catheterization with quantitative cultures falsely localized the infection to the tricuspid valve, probably because the patient was having intermittent rather than continuous bacteremia. After catheterization the patient developed mitral insufficiency and congestive heart failure. This experience suggests that quantitative cultures during cardiac catheterization may give misleading results and that the procedure may have significant complications.

Adult↗
PubMed1985

Selective survival in pentazocine and tripelennamine of Pseudomonas aeruginosa serotype O11 from drug addicts.

The growth of Pseudomonas aeruginosa, particularly serotype O11, in pentazocine and tripelennamine ("T's and Blues") was evaluated as a possible explanation for the association of deep-seated infection with this organism and abuse of these drugs. The mean reduction of growth caused by the drugs was 1,000-fold greater for 49 Pseudomonas strains from normal subjects than for 32 strains from drug addicts (4.2 vs. 1.3 logs of reduction at 2 hr, P less than .0005). A common phenotypic subset of the serotype O11 strains from drug addicts was especially resistant to the inhibitory effects. Twelve strains of Staphylococcus aureus (a frequent cause of infection in heroin, but not in pentazocine and tripelennamine, addicts) were completely inhibited by the drug combination. Dose-response curves (derived from the results of using the tablets as well as pure powders) showed that tripelennamine was responsible for the inhibitory activity, which was partially antagonized by pentazocine. We conclude that an ability of some P. aeruginosa serotype O11 strains, but not S. aureus, to survive in pentazocine and tripelennamine may explain in part a shift from S. aureus to P. aeruginosa as common pathogens of drug addicts in areas where abuse of this combination of drugs has increased.

Drug Interactions↗
PubMed1985

Occult aminoglycoside resistance in Pseudomonas aeruginosa: epidemiology and implications for therapy and control.

The epidemiology of aminoglycoside-resistant Pseudomonas aeruginosa was evaluated in an intensive care unit (ICU) with serial surveillance cultures of throat and rectum. Bacterial population analysis performed by replica plating of primary isolation plates onto gentamicin-containing agar revealed the presence of resistant subpopulations in the initial isolates from 41 (71%) of 58 consecutive assessable patients; these isolates were stably resistant and proportionately less susceptible to other aminoglycosides. An increase in resistant subpopulations occurred during the ICU stay in 34% of 38 colonized patients cultured serially as opposed to none of 23 followed after ICU discharge (P = .0008). Isolates of P. aeruginosa from patients who received aminoglycosides in the ICU were more likely to show an increase in resistance than were isolates from other patients (55% vs. 11%; P = .005); decreasing resistance after ICU discharge followed discontinuation of antibiotic administration. ICU mortality was higher in patients with increasingly resistant subpopulations (69% vs. 16%; P = .0004). The difficulty in treating infections with P. aeruginosa and in controlling drug resistance likely relates to the common carriage of clinically undetected resistant subpopulations that emerge during therapy.

Aminoglycosides↗
PubMed1985

Diphtheria in the United States, 1971-81.

After a decade-long resurgence, including a large cutaneous diphtheria outbreak in Washington State, the diphtheria incidence rate in the United States reached its lowest recorded level ever in 1980--two patients (0.01 case per million). Mortality paralleled the decline in incidence rate. Only 143 of the 3,141 US counties reported noncutaneous diphtheria patients during 1971-81; most were located in the West. The highest attack rates were experienced by children less than 15 years old (0.8 case per million) and by American Indians (22.6 cases per million). Persons immunized with three or more doses of diphtheria toxoid had a lower death-to-case ratio (1.3 per cent) than totally unimmunized persons (13.4 per cent). The reasons for the dramatic decline in diphtheria incidence rates are unclear, although it has been postulated that the gene for producing diphtheria toxin may be lost from organisms in highly immunized populations. Significant proportions of the adult and elderly populations are susceptible to diphtheria. Continuation of primary immunization with increased emphasis on the routine use of tetanus and diphtheria toxoids (Td) boosters in adults should ensure that diphtheria will remain largely a scourge of the past.

Adolescent↗
PubMed1985

Antibiotic-resistant flora in nursing home patients admitted to the hospital.

To study carriage of multiply resistant gram-negative bacilli, 50 patients admitted to the hospital from nursing homes (NHs) and 50 control admissions not from NHs were matched for age and recent antibiotic use. Their antibiotic resistance patterns were similar: 20 NH patients and 14 controls had resistant strains. However, significantly more patients (64%) from NHs with large numbers of "skilled beds" had resistant bacteria than did patients from small NHs (21%) or controls (28%). Also, more patients from NHs had members of the Proteus-Providencia-Morganella group in their urine than did controls. Discriminant analysis showed that residence in NHs with large numbers of skilled beds, recent antibiotic use, and bladder dysfunction (indwelling catheter or incontinence) were independently important in predicting carriage of resistant strains in NH and control patients. Over 75% of resistant isolates were from rectal specimens, emphasizing the occult way that such strains are brought into the hospital.

Aged↗
PubMed1985

Occurrence of cefotaxime-resistant Enterobacter during therapy of cardiac surgery patients.

During 1981-1984, nine patients were treated with second or third generation cephalosporins for deep post-operative wound, respiratory, and blood infections with Enterobacter. In at least 50-60% of cases, therapy failed due to emergence of broad-spectrum cephalosporin resistance. Laboratory testing of two strains that became resistant showed that they were more likely to develop high level resistant mutants, which had greater ability to bind cefotaxime. Although these surgery patients represent an extreme case, spread of their resistant strains to other patients in hospital could lead to wide-spread nosocomial resistance.

Cardiac Surgical Procedures↗
PubMed1984

Epidemiology of endemic Pseudomonas aeruginosa: why infection control efforts have failed.

The epidemiology of Pseudomonas aeruginosa was evaluated in an intensive care unit for a period of six months by means of serial surveillance and environmental cultures. One hundred (37%) of 270 patients were noted to be colonized: 63 at the time of their admission and 37 during their stay on the unit. Colonization at the time of admission was associated with length of hospitalization before admission to the intensive care unit, age, gastrointestinal disease, and prior use of antibiotics. The strains acquired on the intensive care unit represented several different serotypes, with little clustering; the source of most strains was not found. In only 12 cases did the acquisition of P. aeruginosa appear to represent cross-infection; the use of barrier isolation could have prevented at most five of these cases. Undetected endogenous gastrointestinal carriage may have been responsible for many other apparent acquisitions. Clinical infection in association with preceding gastrointestinal colonization developed in 20 patients. The data indicate that traditional control measures aimed at the prevention of exogenous acquisition of P. aeruginosa are unlikely to have an impact on the overall incidence of infection and that efforts to prevent infection in patients who are already colonized are necessary.

Communicable Disease Control↗
PubMed1984

Association of infection caused by Pseudomonas aeruginosa serotype O11 with intravenous abuse of pentazocine mixed with tripelennamine.

From July 1979 to June 1983, 25 of 40 intravenous drug addicts with systemic infections had Pseudomonas aeruginosa as the etiological agent; by 1982, P. aeruginosa had replaced Staphylococcus aureus as the most common pathogen. At least 21 of the 25 addicts with P. aeruginosa infection abused pentazocine mixed with tripelennamine (commonly known as T's and blues) compared with 6 of 15 addicts infected with other pathogens (P = 0.006). Of the 25 P. aeruginosa isolates, 23 were of serotype O11. Phenotypic patterns in isolates from addicts and in 22 serotype O11 control isolates from nonaddicts were determined by pyocin and electrophoretic enzyme typing, as well as by susceptibility to heavy metals and antibiotics. Of 25 isolates from addicts, 20 were identical or differed by only one marker, whereas the 22 nonaddict serotype O11 isolates were distributed among 17 distinct phenotypic patterns. We postulate that the emergence of P. aeruginosa as the major cause of deep infection in addicts is a consequence of contamination of their paraphernalia during preparation of pentazocine and tripelennamine for self-injection. The phenotypic similarity among isolates from addicts may reflect acquisition from related environmental sources and an unusual ability of certain serotype O11 strains to survive preparation of the drugs or to be invasive.

Drug Contamination↗