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Biomedical subjects

D Rimland

Publications and source records attributed to D Rimland.

At least 55 records · Page 3Linked to original sources
PubMed1993

A prospective evaluation of Mycobacterium avium complex colonization of the respiratory and gastrointestinal tracts of persons with human immunodeficiency virus infection.

To describe the natural history of Mycobacterium avium complex (MAC) in the respiratory or gastrointestinal tract of persons with human immunodeficiency virus (HIV) infection, 67 HIV-infected patients with CD4+ cell counts < 200/mm3 and initial negative MAC blood cultures were followed prospectively. Patients were screened every 3 months with cultures and smears of sputum, rectal swab, and blood for mycobacteria. Fourteen patients (20.9%) developed positive blood cultures for MAC (23.4%/year). Sputum cultures revealed MAC in 3 (21%) of the 14 patients at 1, 2, and 8 months before dissemination; no smears were positive. No rectal swab cultures or smears were positive before dissemination. Colonization of the respiratory and gastrointestinal tracts in persons with HIV infection and < 200/mm3 CD4+ cells is infrequently detected with currently available techniques. Screening cultures and smears of sputum and stool do not appear to be sensitive methods for detection of early MAC infection.

Antigens, CD↗
PubMed1993

Randomized double-blinded trial of rifampin with either novobiocin or trimethoprim-sulfamethoxazole against methicillin-resistant Staphylococcus aureus colonization: prevention of antimicrobial resistance and effect of host factors on outcome.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major pathogen in hospitals. Current antimicrobial regimens for eradicating colonizing strains are not well defined and are often complicated by the emergence of resistance. The combination of novobiocin plus rifampin in vitro and in vivo was found to prevent the emergence of resistant populations of initially susceptible strains of MRSA, particularly resistance to rifampin. We therefore studied, in a randomized, double-blind, multicenter comparative trial, the combination of novobiocin plus rifampin versus trimethoprim-sulfamethoxazole (T/S) plus rifampin in order to determine the efficacy of each regimen in eradicating MRSA colonization and to further characterize the host factors involved in the response to this antimicrobial therapy. Among the 126 individuals enrolled in the study, 94 (80 patients; 14 hospital personnel) were evaluable. Among the 94 evaluable subjects, no significant demographic or medical differences existed between the two treatment groups. Successful clearance of the colonizing MRSA strains was achieved in 30 of 45 (67%) subjects receiving novobiocin plus rifampin, whereas successful clearance was achieved in 26 of 49 (53%) subjects treated with T/S plus rifampin (P = 0.18). The emergence of resistance to rifampin developed more frequently in 14% (7 of 49) of subjects treated with T/S plus rifampin than in 2% (1 of 45) of subjects treated with novobiocin plus rifampin (P = 0.04). Restriction endonuclease studies of large plasmid DNA demonstrated that the same strain was present at pretherapy and posttherapy in most refractory cases (24 of 29 [83%] subjects). Among the 56 successfully treated subjects, clearance of MRSA was age dependent: 29 of 36 (80%) subjects in the 18- to 49-year-old age group, 19 of 35 (54%) subjects in the 50- to 69-year-old age group, and 8 of 23 (35%) in the 70- to 94-year-old age group (P < 0.01). Clearance was also site dependent; culture-positive samples from wounds were related to a successful outcome in only 22 (48%) of 46 subjects, whereas culture-positive samples from sites other than wounds (e.g., nares, rectum, and sputum) were associated with a success rate of 34 of 48 (71%) subjects (P = 0.02). Foreign bodies in wounds did not prevent the eradication of MRSA by either regimen. T/S plus rifampin was less effective in clearing both pressure and other wounds, whereas novobiocin plus rifampin was equally effective in clearing both pressure and other wounds. There were no significant differences in toxicity between the two regimens. Thus, the combination of novobiocin plus rifampin, in comparison with T/S plus rifampin, was more effective in preventing the emergence of resistance to rifampin and demonstrated a trend toward greater activity in clearing the MRSA carrier state. The response to either combination depended on host factors, particularly age and the site of MRSA colonization.

Adolescent↗
PubMed1992

Epidemiologic typing of Staphylococcus aureus by DNA restriction fragment length polymorphisms of rRNA genes: elucidation of the clonal nature of a group of bacteriophage-nontypeable, ciprofloxacin-resistant, methicillin-susceptible S. aureus isolates.

Analysis of DNA restriction fragment length polymorphisms of rRNA genes (ribotyping) was employed to assist in the epidemiologic investigation of the emergence and spread of ciprofloxacin-resistant Staphylococcus aureus at the Atlanta VA Medical Center because many isolates of interest were nontypeable by phages and harbored few plasmids useful as strain markers. Chromosomal DNAs of selected S. aureus isolates were digested initially with 20 different restriction enzymes. EcoRI appeared to give the best discrimination of hybridization banding patterns (ribotypes) and was used with all study isolates. Overall, 15 different ribotypes were seen among the 50 S. aureus isolates studied (7 ribotypes among 13 methicillin-susceptible S. aureus [MSSA] isolates and 9 ribotypes among 37 methicillin-resistant S. aureus [MRSA] isolates). Seven of eight ciprofloxacin-resistant MSSA (CR-MSSA) patient isolates had identical antibiograms, were nontypeable by phages, and had a single 22-MDa plasmid. Six of these seven CR-MSSA isolates had an identical ribotype pattern. Ribotyping distinguished this CR-MSSA strain or clone from MRSA and other MSSA isolates, including nontypeable isolates that contained a 22-MDa plasmid. Five ciprofloxacin-susceptible MSSA isolates studied had five ribotypes; one pattern was identical to the CR-MSSA clone. Twenty-three CR-MRSA isolates recovered from the Atlanta VA Medical Center had four different ribotypes. Ribotyping proved to be a useful molecular epidemiologic tool in the study of S. aureus because it differentiated isolates which were indistinguishable by more traditional methods. In addition, this technique demonstrated that at our institution, ciprofloxacin resistance emerged in multiple strains of MRSA, as opposed to primarily a single strain or clone of MSSA.

Bacterial Typing Techniques↗
PubMed1991

Rapid development of ciprofloxacin resistance in methicillin-susceptible and -resistant Staphylococcus aureus.

The fluoroquinolones, particularly ciprofloxacin, have been suggested to treat methicillin-resistant Staphylococcus aureus (MRSA) infections and colonization and methicillin-susceptible S. aureus (MSSA) infections. The development of ciprofloxacin resistance in MRSA and MSSA was prospectively evaluated. After 3 months of ciprofloxacin use, high-level resistance (MIC90, 64 micrograms/ml) developed in MRSA and increased at an alarming rate, from none to 79% over a 1-year period. High-level ciprofloxacin resistance also developed in MSSA, increasing to 13.6% over the same period. Antibiograms, phage typing, and plasmid profile analysis suggest that more than one clone of MRSA developed resistance and that ciprofloxacin resistance is not associated with the acquisition of a new plasmid. Most patients had nosocomial acquisition and about one-half had a history of previous ciprofloxacin use. Ciprofloxacin resistance can develop rapidly in S. aureus; thus, ciprofloxacin appears to have limited usefulness in treating staphylococcal infections and colonization, especially those due to MRSA.

Ciprofloxacin↗
PubMed1989

Analysis of amikacin-resistant Pseudomonas aeruginosa developing in patients receiving amikacin.

During a 36-month period, 28 patients treated for infections due to amikacin-susceptible Pseudomonas aeruginosa subsequently developed infections or colonization with amikacin-resistant P aeruginosa at the same site. Eleven amikacin-susceptible/-resistant pairs of isolates were analyzed for aminoglycoside-inactivating enzymes, plasmid profiles, cellular proteins, outer membrane proteins (OMPs), lipopolysaccharide (LPS) profiles, and amikacin uptake. While clearly distinct from isolates of other patients, sensitive and resistant isolates from the same patients were indistinguishable in plasmid profile, LPS profiles, and OMPs. These results suggest that the resistant P aeruginosa isolates were derived from the sensitive isolates. None of the resistant isolates produced enzymes known to inactivate amikacin. In nine of 11 resistant isolates tested, transport of amikacin into P aeruginosa was reduced. A major mechanism of in vivo development of amikacin resistance in P aeruginosa is alteration in permeability to amikacin, but the aquisition of plasmids or changes in OMPs or LPS profile may not account for this phenomenon.

Amikacin↗
PubMed1988

The roles of vaccination and amantadine prophylaxis in controlling an outbreak of influenza A (H3N2) in a nursing home.

An outbreak caused by influenza A/Philippines/2/82 (H3N2)-like viruses occurred in a partially vaccinated nursing home population in January 1985. During the first six days of the outbreak, 14 (25%) of 55 residents developed influenzalike illness. The risk of illness was most strongly associated with undetectable levels of antibody against the epidemic strain, with unvaccinated case-patients having more severe illnesses and a higher rate of hospitalization than vaccinated case-patients (5/8 vs 0/6). During the period of amantadine hydrochloride prophylaxis (100 mg/d) from days 7 to 35, only two (5%) of the remaining 41 residents became ill, even though 11 (27%) had no detectable antibody. Serum amantadine levels obtained on day 35 ranged from 117 to 737 ng/mL (mean 309 ng/mL), similar to therapeutic levels documented in younger adults who have taken the standard regimen of 200 mg/d; there were few clinically significant side effects. These findings illustrate the benefits of influenza vaccination and support the use of amantadine hydrochloride at a dosage of 100 mg daily for outbreak control among elderly persons.

Adult↗
PubMed1987

Common variable hypogammaglobulinemia complicated by an unusual T-suppressor/cytotoxic cell lymphoma.

A patient with common variable hypogammaglobulinemia (CVH) who presented with recurrent sinopulmonary infections, nodular lymphoid hyperplasia of the small bowel, and intestinal giardiasis was studied. A diffuse lymphocytic lymphoma with small bowel, skin, and hepatic involvement subsequently developed in the patient. Light microscopy of the tumor revealed tissue infiltration with mononuclear cells having the morphologic features of T-lymphocytes. The malignant lymphocytes had characteristics of T-suppressor/cytotoxic cells as established by the absence of surface immunoglobulin and Leu 3 surface markers, and the presence of OKT3 and OKT8 surface markers. Peripheral blood lymphocyte studies revealed an increased number of T-suppressor cells, a reversal of the helper-suppressor ratio, and a generalized state of hyporesponsiveness to mitogen and antigen stimulation. No evidence of retroviral reverse transcriptase activity was detected in cultures of peripheral blood lymphocytes. The association between CVH and a lymphoma composed of cells with T-suppressor/cytotoxic surface markers has not been previously reported. The postulated role of T-suppressor cells in the failure of immunoglobulin synthesis in some forms of CVH suggests that the finding of a T-suppressor/cytotoxic cell lymphoma complicating CVH may be more than fortuitous.

Agammaglobulinemia↗
PubMed1987

Lack of correlation of slime production with pathogenicity in continuous ambulatory peritoneal dialysis peritonitis caused by coagulase negative staphylococci.

In order to evaluate the association of slime production by coagulase-negative staphylococci (CNS) and pathogenicity in the setting of continuous ambulatory peritoneal dialysis (CAPD), we prospectively studied 23 CAPD patients with positive dialysate cultures for CNS during a 12-mo period. Patients were categorized into groups with peritonitis or contaminants. In addition, 24 skin flora isolates of CNS from nine uninfected CAPD patients were compared to the other two groups. We found 14 patients with peritonitis and nine with contaminants. Fifty percent of the peritonitis isolates produced slime, compared to 67% of the contaminants (p = 0.72) and 54% of the skin flora isolates (p = 0.93). Slime production was not associated with specific antibiotic susceptibility patterns or speciation. In this prospective study, slime production was not associated with pathogenicity in CAPD peritonitis caused by coagulase-negative staphylococci.

Coagulase↗
PubMed1987

Methicillin-resistant Staphylococcus aureus in Veterans Administration Medical Centers.

To determine the frequency of isolation of methicillin-resistant Staphylococcus aureus (MRSA) at Veterans Administration Medical Centers, 163 hospitals were surveyed; 137 responded. Between 1975 and 1984, the number of Veterans Administration Medical Centers with known MRSA increased from 3 to 111. This increase was geographically widespread and occurred in hospitals of all sizes. In Veterans Administration Medical Centers, isolation policies for MRSA-infected patients were (% of hospitals using): strict (19%), contact (52%), site-related (28%), no isolation (1%). For patients colonized with MRSA policies were: strict (15%), contact (44%), site-related (35%), and no isolation (6%). Only 41% of Veterans Administration Medical Centers reported discharging known MRSA-colonized patients to nursing homes. Most attempts to eradicate MRSA carriage used trimethoprim-sulfamethoxazole plus rifampin with or without bacitracin ointment; success rates were low. MRSA incidence is increasing at Veterans Administration Medical Centers across the United States. Improved regimens to eliminate MRSA carriage are needed.

Cross Infection↗
PubMed1987

Spontaneous peritonitis: a reappraisal.

Spontaneous bacterial peritonitis occurs frequently in cirrhotic patients. In order to define more accurately the spectrum of this disease, 55 cases of spontaneous peritonitis were compared with 56 controls (patients with negative ascitic fluid cultures). Of several presenting symptoms, only vomiting (p less than 0.01), fever (p less than 0.05), and severe gastrointestinal bleeding (p less than 0.05) were more prevalent in cases than controls. There were no physical signs and no laboratory studies that separated the two groups except for elevated serum amylases in controls. Studies of peritoneal fluid were rarely helpful and cell counts overlapped in the cases and controls. Spontaneous peritonitis is usually seen in patients with severe liver disease, but there are few distinctive symptoms, signs, or laboratory findings. The mortality rate is high, and it is uncertain from our data that antibiotic therapy alters this prognosis.

Adult↗
PubMed1986

Development of antibiotic resistance by staphylococcus aureus in a single patient. Confirmation by phage typing, antibiograms, and plasmid analysis.

A patient is described who had colonization and infection with strains of Staphylococcus aureus increasingly resistant to multiple antibiotics while receiving several courses of broad-spectrum antibiotics. S. aureus strains with different phage types, antibiograms, and plasmid profiles were isolated from different sites at the same time. After the patient was transferred to an intermediate-care service where he received only supportive care and no further antibiotics, culture samples from areas previously colonized or infected (sputum, anterior nares, perineal region, rectum) showed no S. aureus. This patient graphically demonstrates that antibiotics may create an environment allowing the overgrowth of resistant organisms and that withdrawal of this selection pressure may allow more sensitive organisms to recolonize.

Adult↗
PubMed1986

Plasmid analysis of simultaneous nosocomial outbreaks of methicillin-resistant Staphylococcus aureus.

A large outbreak of infections caused by methicillin and aminoglycoside resistant Staphylococcus aureus provided the opportunity to evaluate mechanisms of resistance and compare the usefulness of typing systems. Between January 1979 and December 1980, 63 patients developed infections with S aureus resistant to multiple antibiotics, including methicillin and tobramycin. All isolates had an identical antibiogram and were phage type 47/54/75/77/83A. Beginning in January 1981, a superimposed outbreak caused by S aureus of the same phage type but with a resistance pattern now including gentamicin occurred. The two strains contained different aminoglycoside inactivating enzymes. The initial strain contained a single plasmid of 21.5 mDa molecular weight, whereas the subsequent strain which had acquired gentamicin resistance contained this plasmid plus a heavier one of 33 mDa. Plasmid analysis complements the analysis of antibiograms and phage types and aids in defining epidemiologic patterns of transmission.

Bacteriophage Typing↗
PubMed1986

Gastrointestinal carriage of methicillin-resistant Staphylococcus aureus.

Nasal and rectal cultures were taken from all patients with methicillin-resistant Staphylococcus aureus identified on routine cultures obtained because of clinical indications. Of 117 patients studied over a 3-year period, 70 (60%) had rectal colonization and 62 (53%) had nasal colonization. Rectal colonization, probably reflecting gastrointestinal carriage, may be a source of transmission of methicillin-resistant S. aureus in hospitalized patients and may be difficult to eradicate.

Cross Infection↗
PubMed1985

Nosocomial infections with methicillin and tobramycin resistant Staphylococcus aureus--implication of physiotherapy in hospital-wide dissemination.

From January 1979 to July 1980, methicillin and tobramycin resistant Staphylococcus aureus was isolated from 45 patients at a Veteran's Administration hospital. Of these 45, 36 (80%) had clinical infections involving non-surgical wounds (16), urinary tract (10), blood (8), surgical wounds (7), and sputum (5). The epidemic strain had a single phage type (47/54/75/77/83A), a single, 16.4 Md plasmid, and produced an aminoglycoside inactivating enzyme (AAD[4']). Compared to a control group of patients with nosocomial antibiotic susceptible S. aureus infections, patients with the epidemic strain had more hospital days before a positive culture (p = .004), more severe underlying disease (p = .006), received antibiotics more often (p = .0018), and underwent physiotherapy more often (p = .00007). Although selected environmental and personnel cultures were negative for the epidemic strain, epidemiologic investigation suggested that hospital-wide dissemination of S. aureus may have occurred through patient contacts in the physiotherapy department with subsequent clusters of cases occurring on several wards.

Adult↗
PubMed1985

Alcoholism, leukopenia, and pneumococcal sepsis.

Pneumococcal bacteremia is associated with a high morbidity and mortality, especially when leukopenia is present. To define further the possible factors associated with death in pneumococcal bacteremia, we reviewed all cases at 2 hospitals over a 1-yr period. Overall, increased mortality was associated with women (p = 0.009), nosocomial acquisition of the disease (p = 0.001), the presence of leukopenia (p = 0.00002) or thrombocytopenia (p = 0.025), shock (p = 4 X 10(-8)), and adult respiratory distress syndrome (p = 2 X 10(-7)). Leukopenic and nonleukopenic patients were compared further to ascertain factors that may predispose to leukopenia. Alcoholism was the only associated condition correlating with the presence of leukopenia (p = 0.036), and alcoholism and leukopenia occurred in a group of younger men. We conclude that the association of alcoholism, leukopenia, and pneumococcal sepsis is a distinct clinical entity seen in younger patients and is associated with a very high mortality.

Alcoholism↗