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Biomedical subjects

J L Staneck

Publications and source records attributed to J L Staneck.

At least 37 records · Page 2Linked to original sources

Sensititre autoreader for same-day breakpoint broth microdilution susceptibility testing of members of the family Enterobacteriaceae.

The Sensititre Autoreader system is an instrument-assisted broth microdilution susceptibility test procedure based on the detection of fluorogenic growth substrate metabolism by test bacteria with different concentrations of antimicrobial agents. In the current investigation, this system was assessed as a means for predicting the in vitro activity of 17 antimicrobial agents versus numerous species of the family Enterobacteriaceae and Pseudomonas aeruginosa by using a breakpoint broth microdilution test format. Same-day and overnight determinations of susceptibility were made with the Sensititre Autoreader system, and in both cases, the results were compared with those obtained with a manual overnight breakpoint broth microdilution susceptibility test. Among a total of 6,086 organism-antimicrobial agent comparisons with Enterobacteriaceae, concordance was noted between the results of the same-day Autoreader system and the manual overnight test in 94.4% of cases. The same-day Autoreader results with members of the Enterobacteriaceae other than Proteus spp. were determined after 4 h of incubation; with Proteus spp. the same-day Autoreader results were determined after 5 h of incubation. When the Enterobacteriaceae Autoreader results were determined after 18 h of incubation, concordance was noted in 97.2% of comparisons. Among a total of 1,377 organism-antimicrobial agent comparisons with P. aeruginosa after 18 h of incubation, agreement of results from the manual overnight test and the Autoreader system was achieved in 92.2% of cases.

Anti-Bacterial Agents↗

Performance characteristics of a commercially prepared biphasic blood culture bottle.

A biphasic blood culture bottle (BiPB: GIBCO Laboratories, North Andover, Mass.) with an architectural design that physically separates the agar slant from the broth was compared with a conventional vented monophasic bottle (MPB-A) for use in the routine culture of blood. Both bottles contained tryptic soy broth. Tryptic soy agar was used for the BiPB slant. A third unvented bottle (MPB-N) with Columbia broth was included as part of the blood culture set. Of 3,537 sets collected, 444 were positive; 57 of these 444 sets were positive by virtue of an exclusively positive anaerobic bottle. Both BiPB and MPB-A were positive in 235 of the remaining 387 positive sets. A total of 521 isolates was recovered during the study. Of these isolates, 252 were recovered in both the BiPB and the MPB-A from the same set; 105 isolates grew in the BIPB but not in MPB-A, 95 isolates grew only in the MPB-A but not in BiPB, and 69 grew exclusively in the MPB-N. The BiPB allowed more rapid recovery of Candida spp., J-K diphtheroids, Pseudomonas spp. Making BiPB subcultures was easy enough to permit both early and daily subculture, which provided isolated colonies sooner than could be done by using the MPB-A. Isolated colonies and, therefore, identification and susceptibility results were available at least 1 day earlier for the BiPB isolates in approximately 50% of instances when both the BiPB and the MPB-A were positive. Staphylococcus epidermidis and streptococci were recovered more frequently in the BiPB, while gram-positive anaerobes were detected at a significantly (P less than 0.025) more frequent rate in the MPB-A than in the BiPB. Either bottle, however, should be used in conjunction with an anaerobic bottle for optimal recovery of anaerobic bacteria.

Bacteria↗

Imipenem susceptibility testing with a commercially prepared dry-format microdilution tray.

MICs of imipenem, concurrently generated in commercially prepared microdilution trays containing predried antibiotic dilutions (Sensititre), and in a standard agar dilution assay (as recommended by the National Committee for Clinical Laboratory Standards, Villanova, Pa.), were within +/- 1 twofold dilution for 94% of 226 bacterial isolates. Imipenem biological activity remained stable over 5 months of tray storage at room temperature against Pseudomonas aeruginosa ATCC 27853. Activity of imipenem was shown by microdilution testing with 890 clinical isolates to be high, with only 4% of isolates having MICs of greater than or equal to 16 micrograms/ml (in vitro resistance).

Bacteria↗

Screening tests and "rapid" identification. Is anybody out there listening?

The responses by 55 of 300 physicians queried at the University Hospital, Cincinnati, to an extensive questionnaire, form the basis for this comment on the clinical impact of screening tests and rapid identification. Examination and interpretation of smears of fluids and tissue were felt to provide useful data within a short time of specimen collection and the majority of physician respondents were willing to sacrifice some degree of accuracy in results in return for an answer delivered shortly after specimen submission. Screening for bacteriuria was felt to be useful if the test was sensitive enough to rule out infection as suggested by the presence of approximately 10,000 CFU/ml of urine, if results could be had within 1 hr of specimen collection for outpatients, 2 hr for inpatients, and if test results for pyuria accompanied the screen results. The value of taxonomy, in general, was directly related to how much knowing the taxon would direct antibiotic therapy. The time required for a taxonomic result seemed to matter only when susceptibility test results were either delayed or not forthcoming. Interest in the taxonomy of anaerobic bacteria appeared to be limited to a small group of physician respondents (infectious disease specialists) and also was relative to the ability of the taxonomic designation to evoke a specific therapeutic regimen. In summary, the impact of microbiologic data on the practice of medicine appears to depend on the ability of the laboratory to complete the entire test process, from order to transmission of answer, within a time frame perceived to be useful by the clinician.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacteriological Techniques↗

Prolonged hospital epidemic of salmonellosis: use of trimethoprim-sulfamethoxazole for control.

The occurrence of a foodborne outbreak of Salmonella drypool, an uncommon serotype, led to the recognition of hospital-acquired cases occurring over a 5-year period. In late 1981, a catered luncheon resulted in an epidemic of S. drypool, and in retrospect, cases were found to have been occurring in hospital patients from 1977 until 1981. Over the next 4 months, patients, employees, and 50% of the kitchen workers became infected, despite repeated culture surveys of the staff and removal of all infected workers. Food and environmental cultures failed to reveal the source of infection, but infected workers were observed to have multiple negative cultures over several months and then to become positive again. Closing of the kitchen for 2 weeks failed to stop the epidemic. Finally, all kitchen employees, both infected and uninfected, were treated with trimethoprim-sulfamethoxazole for 2 weeks. After treatment, no new kitchen workers became infected, although two workers who had had positive cultures earlier in the epidemic began to excrete S. drypool again, and the epidemic ended.

Carrier State↗

Clinical trial of the efficacy and safety of ticarcillin and clavulanic acid.

Forty-three hospitalized patients were treated with a new antibiotic combination containing ticarcillin plus the beta-lactamase inhibitor, clavulanic acid, in a fixed combination for intravenous use. A variety of infections were treated, including pneumonia, bacteremia, urinary tract infection, and osteomyelitis. Of 50 episodes of infection in 43 patients, 44 clinical cures were obtained, with 5 patients improving and 1 patient failing to respond to treatment. In vitro susceptibility testing of 101 clinical isolates was notable for the rarity of resistance to the combination antibiotic. Of specific interest, all 14 isolates of Staphylococcus aureus were susceptible to ticarcillin plus clavulanic acid, whereas only 2 of the 14 isolates were susceptible to ticarcillin alone. Adverse reactions to the study drug were minimal; eosinophilia, unaccompanied by other allergic phenomena, and oral candidiasis were most frequent. Overall, the combination of ticarcillin with the beta-lactamase inhibitor, clavulanic acid, appears to be a safe and effective drug for the treatment of infections caused by susceptible organisms.

Aged↗

Bacteriuria screening by use of acridine orange-stained smears.

Acridine orange (AO)-stained smears of 1,042 urine specimens were examined for the presence of bacteria and compared with quantitative culture results. The detection of one or more organisms per three AO fields at X200 magnification was noted in 161 of 162 and 193 of 195 urine specimens that grew greater than 10(5) and 10(4) CFU/ml, respectively, of a clinically relevant organism. However, a high number of false-positive AO smears (356 and 324, respectively) was observed among urines that failed to grow organisms at 10(5) and 10(4) CFU/ml. Sensitivity, specificity, and positive and negative predictive values of AO smears were 99, 58, 26, and 99%, respectively, for cultures of greater than or equal to 10(5) CFU/ml and 98, 59, 32, and 99%, respectively for cultures of greater than or equal to 10(4) CFU/ml. Despite the poor specificity of the AO smear, the very high negative predictive value would allow for the ruling out of bacteriuria defined at 10(4) CFU/ml and would eliminate the need for culture of ca. 50% of the urine specimens in this study. Employment of the rapid, inexpensive AO procedure only as a means to eliminate specimens for culture would allow significant cost savings and permit the laboratory to send out a large number of potentially negative or low-count urine results within a short time of specimen receipt.

Acridine Orange↗

Automated reading of MIC microdilution trays containing fluorogenic enzyme substrates with the Sensititre Autoreader.

The Sensititre Autoreader is a microcomputer-driven instrument capable of automatically reading antimicrobial susceptibility microdilution trays. The instrument measures the fluorescence liberated by bacterial enzymatic activity on fluorogenic substrates as an indicator of growth in each well. A mathematical algorithm converts the fluorescent signals from an antimicrobial dilution series to an MIC endpoint. A three-center study evaluated the performance of the Autoreader in comparison with MIC determined visually in a duplicate set of control plates lacking fluorogenic substrate. Among 828 isolates of gram-negative bacilli tested against 17 antimicrobial agents, Autoreader 18-h MIC were within +/- 1 twofold dilution of control MIC values (agreement) in 95.3% of instances. In 3.5% of the instances, Autoreader values occurred +/- 2 half-step dilutions from control values (minor discrepancy), and in only 1.2% of instances did Autoreader values deviate from control values by greater than +/- 2 dilution steps (major discrepancy). Agreement, minor discrepancies, and major discrepancies were noted among 148 gram-positive cocci tested against 11 antimicrobial agents in 93.5, 4.8, and 1.7% of the instances, respectively. Over half of the major discrepancies noted with gram-negative bacilli occurred with Proteus mirabilis-beta-lactam combinations, a problem that was resolved when a lower initial inoculum was used. Inter-and intralaboratory reproducibility was excellent. Standard Sensititre susceptibility trays may be instrument read at 18 h reproducibly and accurately with only slight modification of conventional procedures to include fluorogenic enzyme substrates in the incubation broth.

Anti-Bacterial Agents↗

Cutaneous abscesses: natural history and management in an outpatient facility.

This study investigated the natural history and treatment of cutaneous abscesses in an outpatient setting. Incision, drainage, aerobic and anaerobic cultures were done on all 78 patients entered in the study. Tenderness and fluctuance were noted in more than 80% of the patients; erythema and induration in more than 60%. Forty-one percent of all abscesses were in the anogenital region. Forty-two percent of cultured abscesses grew aerobes exclusively, 28% grew anaerobes exclusively, and 27% grew a mixture of aerobes and anaerobes. The predominant aerobic organisms were Staphylococcus and Streptococcus, which were mostly isolated from the head/neck, extremities, and axillary regions. The predominant anaerobic organisms were Peptococcus and Bacteroides, which were primarily isolated from the anogenital regions. Nearly 60% of the patients returned for reevaluation. They were equally divided between those patients taking antibiotics and those not on antibiotics. However, all patients were clinically improved.

Abscess↗

Antibody responses to toxic-shock-syndrome (TSS) toxin by patients with TSS and by healthy staphylococcal carriers.

Serum samples taken from women with toxic-shock syndrome (TSS) and from women without a history of TSS were examined for the presence of antibodies to toxic-shock-syndrome toxin (TST). Serum samples from 38 women with TSS and from 70 women with no history of TSS were analyzed by radioimmunoassay (RIA) and by an enzyme-linked immunoadsorbent assay (ELISA). Antitoxin titers obtained by the assays were highly correlated. Antibody levels in sera of women with TSS, or a history of TSS, were significantly lower than levels in sera of women with no prior evidence of TSS. The mean level of antitoxin titers in the total sample of acute, convalescent, and recovered TSS groups was significantly lower than that of the control groups, which consisted of 31 carriers of genital Staphylococcus aureus and a similar number of age- and race-matched noncarriers. Although a trend toward elevated antitoxin titers was apparent after recovery, no vigorous immunologic response to TST was noted. In contrast, the majority of healthy women demonstrated measurable antitoxin titers, a finding indicative of current or prior colonization with TST-producing strains of S. aureus. The data suggest that absence of antibodies to the TSS toxin may be a predisposing factor in the development of clinical disease.

Antitoxins↗

Rapid screening assay for toxic shock syndrome toxin production by Staphylococcus aureus.

A rapid immunoblot assay (TST-blot) was developed and used to screen Staphylococcus aureus isolates for toxic shock syndrome toxin (TST) production. Growth from an 18-h stab inoculum of S. aureus on brain heart infusion agar was transferred directly to a nitrocellulose sheet. Nonspecific protein binding sites were blocked with bovine serum albumin, and the nitrocellulose sheet was incubated with affinity-purified antibody to TST, followed by incubation with horseradish peroxidase-conjugated protein A. Toxin was visualized by detection of the peroxidase-conjugated protein A-anti TST-TST complex with 4-chloro-1-napthol. The sensitivities and specificities of the TST-blot and Ouchterlony microslide immunodiffusion assay were compared by screening 141 S. aureus isolates for TST production. In both assays, 53 of 141 isolates produced detectable levels of TST, whereas 88 isolates produced no toxin. A 100% concordance was found between the two assays. The TST-blot yielded the same results in less than 24 h as those yielded by the 3-day immunodiffusion assay. Thus, this rapid method for detection of TST in multiple samples appears to be well suited for diagnostic and epidemiological studies. Furthermore, it would appear to be ideal for use in TST genetics research.

Bacterial Toxins↗

Staphylococcus in toxic shock syndrome and other surgical infections. Development of new bacteriophages.

Recent studies of Staphylococcus aureus isolates from patients with toxic shock syndrome (TSS) have shown the dominance of phage type 29/52 with the capacity to produce pyrogenic exotoxin C and enterotoxin F. They also showed that 29% of the isolates were nontypable and 90% of them had similar toxigenic properties. The existence of unknown and important phages in this disease was postulated. Five new phages were then developed and used for typing three groups of staphylococcal isolates: 236 from patients with TSS, 67 from patients without TSS, and 159 from patients with infected burns. Results showed a high correlation between the lytic action of the new phages and the 29/52 phages, and an additional typing capability in 35% of the previously nontypable TSS isolates, emphasizing further the potential of bacteriophage typing of S aureus in these infections.

Bacteriophage Typing↗

Erysipeloid.

Erysipelothrix infections have been a well-known clinical entity for over a century. Only a few cases have been studied histologically, and the agent has rarely been cultured from infected patients. We present here a case of erysipeloid of Rosenbach, in which histologic study and electron microscopy document the presence of microorganisms. We also present a complete review of the clinical and pathologic features of Erysipelothrix infections and their treatment. Our observations suggest that Erysipelothrix rhusiopathiae is capable of producing L forms that may revert to a bacterial form and produce sepsis at a later time.

Erysipeloid↗

Established hand infections: a controlled, prospective study.

A randomized, prospective study of 200 consecutive established hand infections was designed to compare the efficacy of two antibiotics, cefamandole and nafcillin. Bacteriologic data revealed 63.5% of the patients grew multiple organisms (2.3 organisms per culture) and 26% of the patients had anaerobic infections. Complications were noted in 13% of all patients--26% in patients who grew aerobes and anaerobes and 9.8% in patients who grew aerobes alone (p less than 0.05). Despite the fact that 95% of all organisms were sensitive in vitro to cefamandole whereas only 67% of organisms were sensitive to nafcillin (p less than 0.01), complications occurred more frequently in patients treated with cefamandole. We conclude that the empirical selection of a broad-spectrum antibiotic is reasonable based on in vitro sensitivity studies; however, other factors such as treatment delay, initial extent of infection, anatomic location of infection, cause of infection, and extent of surgical debridement are important in the development of complications.

Adolescent↗

Evaluation of the Sensititre system for identification of Enterobacteriaceae.

The Sensititre identification system (Seward Laboratory/GIBCO Laboratories) consists of a microplate containing a pattern of 24 biochemicals repeated four times together with an automatic inoculation device and a microcomputer-assisted data interpretation component. A total of 1,415 isolates of Enterobacteriaceae plus 6 isolates of other glucose-fermenting gram-negative bacilli were tested in three hospital laboratories in parallel with API 20E (Analytab Products). Discrepancies were resolved by conventional biochemical testing. Sensititre yielded correct identifications at the species level with 94.6% of the isolates and at the genus level with an additional 1.9%. API 20E yielded correct species identification with 91.1% and genus only identification with an additional 6.7% of the isolates. For the routine identification of clinical Enterobacteriaceae isolates, the Sensititre system compares favorably with API 20E and offers clinical laboratories the economy of a microtiter plate system as well as the benefit of a microcomputer capable of other microbiological and data management applications.

Bacteriological Techniques↗

Methicillin-resistant Staphylococcus aureus: experience in a general hospital over four years.

From 1977 to 1981, 317 patients in a large general hospital became infected with methicillin- and gentamicin-resistant Staphylococcus aureus. The epidemic strain was characterized as bacteriophage type D11/83A/85, resistant to methicillin, cephalosporins and aminoglycosides, and contained a 24 megadalton plasmid which mediated gentamicin resistance. Spread within the hospital followed introduction of this organism into the general surgical and burn services and resulted from cross infection between patients. These services remained a reservoir of infection throughout the four-year period. Only 2% of hospital personnel carried methicillin-resistant S. aureus in their anterior nares, and only one of them was shown to be a long-term carrier. During the epidemic, there was no overall increase in serious staphylococcal infections, as reflected in bacteremias. As methicillin-resistant S. aureus increased, there was a reciprocal decrease in methicillin-sensitive S. aureus. Later, as methicillin-resistant S. aureus bacteremias decreased, methicillin-sensitive S. aureus bacteremias increased. Attempts to control the spread of the organism by containing infected patients on an isolation ward, or by placing all such infected patients in strict isolation, decreased the frequency of infections, but did not eliminate the organism. In 1980, the burn service was separated from the surgical service and moved into a new burn unit. Also, the five-bed rooms in the hospital were being converted to two-bed rooms. With only routine isolation precautions, the epidemic resolved over the next year, although the epidemic strain persists in the hospital.

Cross Infection↗

The epidemiology of genital colonization with Staphylococcus aureus.

The prevalence of genital colonization with Staphylococcus aureus, including strains that have been associated with toxic shock syndrome, was studied in 600 women. Nine percent of these women were colonized with S. aureus, 5% of whom had positive vaginal cultures, and 1% were colonized with toxin-producing strains. Black women were colonized with S. aureus, including toxin-producing strains, as frequently or more frequently than white women. The highest colonization rates occurred in postpartum women. Trends toward increasing colonization occurred in relation to decreasing age and socioeconomic status. There were no statistically significant relationships between genital colonization with S. aureus and the use of tampons, oral contraceptives, or a variety of other personal habits and health problems. Genital cultures taken in consecutive menstrual cycles indicated that 35% of women with S. aureus were persistent carriers, and the rest either intermittent or transient carriers. Toxin-producing S. aureus was also identified in family members of women carrying the same organism. This report defines the prevalence of genital colonization in a large population of women, characterizes the women with S. aureus, and describes epidemiologic features of genital carriage.

Adolescent↗