Biomedical subjects
Publications and source records attributed to A B Kaiser.
Patients with bacterial meningitis and posttraumatic and/or postsurgical access to the CSF are at risk for superinfection with Candida species. Patients who are not improving on appropriate antimicrobial chemotherapy for bacterial meningitis or are deteriorating after initial improvement should have a CSF reexamination for Candida superinfection.
We previously have shown that extracts of S. aureus isolates which produce the recognized serotypes of staphylococcal beta-lactamase (A, B, C, D) differ in the rates at which they hydrolyze selected cephalosporins, exhibiting substrate profiles which are distinctive for each serotype. In an effort to simplify the methods employed in identifying the different staphylococcal beta-lactamases, we evaluated whether distinctive substrate profiles could be obtained by using whole-cell suspensions of 115 beta-lactamase-producing isolates of S. aureus. Compared with extracts from the same strains, the whole-cell bacterial suspensions not only were simpler to prepare but enabled beta-lactamase typing of a higher proportion of the evaluated strains (86 versus 97%, respectively). Furthermore, the use of whole-cell bacterial suspensions enabled the simultaneous quantitation of the beta-lactamase activity exhibited by each strain. Additionally, by comparing the quantitative activity of beta-lactamase-induced and -uninduced preparations of the same strain, induction ratios (i.e., induced/uninduced activity) could be derived, yielding information regarding the regulation of beta-lactamase production by each strain. We believe that the utilization of whole-cell methods, such as those employed in this study, will facilitate the investigation of qualitative and quantitative differences in beta-lactamase production among clinical and reference isolates of S. aureus.
The acquisition, administration, and infection-related expenses associated with the use of cefazolin or cefamandole during a prospective randomized comparison of antimicrobial prophylaxis in cardiac surgery were compared. Although the acquisition cost and administration charges related to the use of cefamandole were in excess of those incurred with cefazolin, differences in the charges associated with treating the wound infections that failed prophylaxis with each regimen made cefamandole the more cost-effective prophylactic agent (mean total of $766 per cefazolin recipient vs. $315 per cefamandole recipient). Analysis of prophylactic antimicrobials should include the expenses associated with "prophylactic failures." The agent that is least expensive for the pharmacy may not be the most cost-effective choice for the institution.
In March 1987, 32 hospital employees were enrolled in a prospective trial of intradermal recombinant hepatitis B vaccination. Enrollees were given 0.1 ml of vaccine on days 1, 30, and 180. Two weeks after the third intradermal vaccination, 81%, or 26, of the enrollees showed seropositivity (greater than or equal to 10 mIU antibody/ml) for hepatitis B surface antibody. Five of six nonresponders were given a fourth intradermal vaccination. Two additional seroconversions occurred, resulting in an overall conversion rate of 90% for recipients of up to four intradermal vaccine doses. Complications of vaccination were limited primarily to the occasional persistence (less than 6 months) of hyperpigmentation at the injection site. Administration of recombinant hepatitis B vaccine by the intradermal route proved to be a safe and effective method of vaccination. Cost savings of preexposure immunization with the intradermal versus the intramuscular route of vaccination were approximately $90 per enrollee. Efficacy and safety can be maximized by employing a fourth vaccine dose and routinely documenting seroconversion after vaccination.
Recurrent episodes of mycobacterial cross-contamination of bronchoscopy specimens were identified in a large, tertiary-care referral center. One episode was followed by active pulmonary infection due to Mycobacterium tuberculosis. Initial epidemiologic investigation implicated the flexible fiberoptic bronchoscopes. In experiments, bronchoscopes and related equipment were exposed to a saline suspension of M. fortuitum (10(5)-10(7)/mL). Bronchoscopes were readily sterilized by routine cleaning and disinfection procedures, but the spring-operated suction valves remained contaminated, even after a 30-min exposure to 2% glutaraldehyde or after passage through a commercial bronchoscope washer. These results indicate that suction valves that have been heavily contaminated with mycobacterial organisms cannot be reliably disinfected with commercially available glutaraldehyde. Suction valves have since been routinely autoclaved after each use. No additional episodes of cross-contamination or infection have occurred over 24 mo of surveillance.
After an uncertain and highly controversial beginning, the use of antimicrobials for prophylaxis of surgical wound infection has evolved to represent state-of-the-art management of the surgical patient. Although a truly ideal prophylactic antimicrobial does not exist, the cephalosporins, particularly those of the first generation, have emerged as the mainstay of prophylaxis in surgery. However, new pathogens and newly recognized problems have necessitated a comparative evaluation of a wide variety of antibiotic regimens. The choice of an appropriate antibiotic is complicated by the lack of an adequate experimental model of infection in clean and clean-contaminated surgical procedures. Moreover, clinical trials have proved to be an inefficient method of comparing antibiotic regimens, as important variations in risk factors for infection cannot be reliably controlled. Significant differences exist among cephalosporins and between the cephalosporins and other classes of antimicrobials in several clinically important parameters: antimicrobial spectrum, serum half-life, ease of administration, tissue penetrability, cost, and incidence of allergy and toxicity. New generations of cephalosporins and new classes of antibiotics have demonstrated the potential to out-perform the first-generation cephalosporins in many of these areas. Although the first-generation cephalosporins were essential in establishing the efficacy of antibiotic prophylaxis in surgery, there are no guarantees that this class of cephalosporin, or that any cephalosporin, for that matter, will continue to dominate the prophylactic arena.
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We undertook a prospective randomized observer-blinded study comparing the ability of preoperative showers with chlorhexidine gluconate (Hibiclens), povidone-iodine (Betadine), and a lotion soap (Safe 'N Sure) to diminish the staphylococcal skin flora of patients. By block randomization, patients scheduled for an elective cardiac operation or coronary artery angioplasty were assigned to shower with one of the study skin cleansers either once (evening only) or twice (both evening and morning) before the procedure. Semiquantitative samples for culture were obtained from the subclavian and inguinal sites on the evening before the procedure (baseline culture) and again the next morning before the operation. The chlorhexidine skin cleanser consistently reduced staphylococcal colony counts at both the subclavian and inguinal sites before the procedure. This reduction was significant for patients showering both evening and morning (p less than 0.05). The use of the povidone-iodine skin cleanser inconsistently affected skin flora. Patients using lotion soap either experienced no change or had an increase in colony counts. Chlorhexidine is more effective than povidone-iodine in diminishing skin colonization with staphylococci in patients before operation. Repeated applications of chlorhexidine are superior to a single shower with this agent.
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By use of techniques that have been developed to detect small numbers of methicillin-resistant staphylococci, we cultured samples from the nares and subclavian and inguinal areas of 29 patients before and after cardiac surgery and 10 patients before and after coronary angioplasty. Methicillin-resistant coagulase-negative staphylococci were recovered before the surgical or angioplasty procedure from 74% of patients. The quantitative recovery of methicillin-resistant isolates before cardiac surgery or coronary angioplasty was compared with the number of methicillin-resistant staphylococci detected at the same site 3 days after the procedure. In cardiac surgery patients (who received antibiotic prophylaxis), 17 of the 28 sites (61%) in which low-level colonization with methicillin-resistant strains was detected preoperatively contained high levels of methicillin-resistant staphylococci postoperatively. In contrast, coronary angioplasty patients (who did not receive antibiotic prophylaxis) did not have any of the 14 sites containing low levels of methicillin-resistant strains before angioplasty emerge to harbor high levels of methicillin-resistant staphylococci after angioplasty. Methicillin-resistant coagulase-negative staphylococci from each site in which high levels of methicillin-resistant staphylococci emerged postoperatively were paired with preoperative isolates from the same site. Identical antibiograms and plasmid profile patterns were demonstrated for seven of the pre- and postoperative isolate pairs, suggesting that the high levels of methicillin-resistant coagulase-negative staphylococci detected on the skin or in the nares after cardiac surgery were derived from methicillin-resistant organisms present at the site preoperatively in much smaller numbers.
In an effort to develop an improved regimen of antibiotic prophylaxis in cardiac surgery, 1030 patients who were to have elective cardiothoracic surgery involving a median sternotomy were selected at random to receive cefamandole or cefazolin, with or without gentamicin, in a prospective double-blind study. Cefazolin was significantly less effective than cefamandole at both the sternal (1.8% vs. 0.4%, respectively, p less than 0.05) and donor sites (1.3% vs. 0%, respectively, p less than 0.02). Seven Staphylococcus aureus infections occurred among cefazolin recipients as compared with no such infections among the patients receiving cefamandole (p less than 0.01). All five wound infections yielding fungi or gentamicin-resistant gram-negative rods occurred in patients who had received gentamicin as a second prophylactic agent. These data suggest that gentamicin has no role as a prophylactic antibiotic in cardiac surgery and that, compared with cefamandole, cefazolin offers unreliable prophylaxis against deep infection at both the sternal and donor sites.
We report five cases of infected abdominal aortic aneurysm managed at the St. Thomas Hospital between 1975 and 1985. Two patients died, one before operation, and another during surgical repair of aneurysmal rupture. Three patients survived, all of whom had primary repair of the aorta or in situ Dacron graft reconstruction. One patient is still living nine years after operation. The availability of organism-specific antibiotic agents has enabled us to use the in situ reconstruction method to successfully manage these patients without increased morbidity or mortality from recurrent infection. A high index of suspicion, prompt surgical resection, and aggressive specific antibiotic therapy are necessary for patient survival.
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Rhabdomyolysis as a complication of tularemia occurred in four patients in Tennessee over a four-year period. All patients were severely ill and had renal failure. Tularemia was not suspected initially in any of these patients. One patient died of complications of rhabdomyolysis. At autopsy, multiple abscesses were present within skeletal muscle, suggesting that rhabdomyolysis resulted from direct muscle involvement with Francisella tularensis. Tularemia should be considered in the differential diagnosis of patients with an acute febrile illness and rhabdomyolysis. Conversely, in patients with acute tularemia, the possibility of rhabdomyolysis should be entertained early, especially in those with evidence of myoglobinuria and/or impaired renal function.
An abbreviated method for the surveillance of nosocomial urinary tract infection is described. Combining desirable features of both active and passive surveillance, this new method involves concurrent review of microbiology reports. Compared to traditional active surveillance methods which require review of individual patient charts, the abbreviated method requires only one-fifth the time commitment while maintaining a 98% sensitivity. Although some degree of overestimation is inherent in this method, the primary goals of surveillance--monitoring infection rates and identifying clusters of infection--should be preserved.
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A 60-year-old man with a history of a benign heart murmur for 25 years had evaluation of six months of unexplained fever and heart disease. The fever responded to nonspecific antimicrobial therapy, but progressive aortic insufficiency necessitated aortic valve replacement. Although numerous preoperative blood cultures were negative, Veillonella alcalescens was isolated in pure culture from the excised valve. The patient remained well after two weeks of intravenous therapy with cephalothin and three months of oral therapy with penicillin.