Characteristics of group A streptococcal bacteremia in patients at the San Bernardino County Medical Center.

On the basis of a 12-year study of 58 patients at our medical center who had group A streptococcal bacteremia, we found that this disease is not uncommon when compared with other varieties of bacteremia. It occurs with about one-half of the frequency of bacteremias due to Klebsiella species and one-eighth of that of bacteremias due to Staphylococcus aureus. The infection is infrequently nosocomial (3.5% of cases) and the predominant causes are cutaneous or subcutaneous infections (72% of cases). While many patients are chronically ill, debilitated, or elderly, in our institution, as in some other public hospitals, the most important underlying condition is a history of iv drug abuse (28% of cases). Our data and those of some other recent publications suggest that the occurrence of cases related to iv drug abuse may be increasing. Intravenous drug abusers tend to be young adults, while other sources of infection are found more frequently in older patients. The frequent presence (10.3% of cases) of other organisms (especially S. aureus) in the blood of patients with group A streptococcal bacteremia has not been sufficiently emphasized in previous studies.

Immunity to measles in a large population of varying age. Significance with respect to vaccination.

During a measles outbreak, 660 hospital employees of widely varying ages were screened for immunity to the disease using an automated indirect fluorescent antibody technique. Of these 660 employees, 623 indicated their year of birth; 21 were seronegative and 13 had borderline titers. Of those born before 1957, 7 tested seronegative and 6 were borderline, while 12 of those born between 1959 and 1964 were seronegative and 3 were borderline. There are several possible reasons for these findings. It is concluded that mass immunization of high-risk populations during outbreaks, while effective, is difficult to justify scientifically because only a small percentage of subjects are not immune. If facilities permit, mass screening during outbreaks may be feasible. Preferably, continuous screening and vaccination of susceptible high-risk employees could be performed. Our study also does not validate exclusion from immunization programs those born prior to 1957 in view of the fact that both seronegativity and disease occur in this age group with significant frequency.

The value of microbiologic culture of tissue samples in surgical pathology.

The diagnosis of infectious disease is best achieved, and appropriate therapy best effectuated, by isolation and identification of the causative agent. With appropriate exercise of foresight, the necessary procedures can be carried out readily on tissue samples obtained at surgery for morphologic study. Close cooperation among involved specialists permits microbiologic investigation of surgical specimens to be carried out routinely with results highly beneficial to patient care. Four cases illustrating the value of such studies in facilitating diagnosis and treatment are described.

Quality control in microbiology: a review and bibliography.

Quality control in microbiology, with the proliferation and widespread usage of commercial identification systems, has largely passed into the hands of the manufacturer. In this review the author attempts to provide a spectrum of information concerning the validity, precision, and specificity of commercially available systems and individual methods for the identification of bacteria, of various types of yeasts, and of bacterial antigens, as well as a review of blood culture systems.

Hazardous materials management and control program at Oak Ridge National Laboratory--environmental protection.

At a large research laboratory facility the management and control of hazardous materials, and their subsequent wastes can be an unmanageable task. Environmental regulations, mandated by the Resource Conservation and Recovery Act of 1976, established a Federal program to provide comprehensive regulation of hazardous solid waste materials from their generation time to their disposal. In an effort to comply with these regulations, a Hazardous Materials Management and Control Program was created at Oak Ridge National Laboratory. The program provides personnel with specific guidelines for the procurement, use, storage, transportation and disposal of hazardous materials/wastes, and ensures that they are managed in a manner which adequately protects all personnel, the general public, and the environment.

Detection of malarial parasites in routine Wright-stained blood smears.

Among four cases of malaria, parasites were initially detected in routine Wright-stained blood smears from three. In one of the three, malaria was not suspected until the organisms were seen during routine differential counting. In the fourth, review of the previously unstudied smear indicated that they should have been detectable during routine differential counting. The attention of laboratory personnel is directed to the need for alertness to the possibility that organisms, especially malarial parasites, may be detectable during routine blood film examination. It is suspected that emphasizing the need to look for parasites will not significantly increase the time consumed in such a study. Ability to detect parasites is yet another advantage of direct, as opposed to automated, differential counting.

Urinary kallikrein excretion in essential and mineralocorticoid hypertension.

Urinary kallikrein excretion has been reported to be decreased in patients with essential hypertension and elevated in patients with primary aldosteronism as a reflection of mineralocorticoid activity. Low renin essential hypertension (LREH) has been postulated to result from excess production of an unknown mineralocorticoid(s). Urinary kallikrein excretion was compared in outpatients with essential hypertension, mineralocorticoid hypertension (primary aldosteronism and 17alpha-hydroxylase deficiency), and in normal subjects of the same race. No significant difference in urinary kallikrein excretion of patients with LREH vs. normal renin essential hypertension (NREH) was found for either black (4.1+/-0.4 vs. 4.8+/-0.5 esterase units (EU)/24 h, mean+/-SE, for 27 LREH and 38 NREH, respectively) or white patients (12.2+/-2.3 vs. 11.7+/-1.4 EU/24 h for 13 LREH and 25 NREH, respectively). Urinary kallikrein was decreased in black vs. white hypertensive patients and normal subjects. However, in patients with normal renal function (creatinine clearance >/=80 ml/min) urinary kallikrein was not significantly decreased in either black hypertensive vs. black normal subjects (4.3+/-0.3 vs. 5.4+/-0.6 EU/24 h) or in white hypertensive vs. white normal subjects (11.9+/-1.2 vs. 8.4+/-0.9 EU/24 h). In contrast, hypertensive patients with mild renal insufficiency (creatinine clearance of 41.8+/-78.5 ml/min) had reduced (P < 0.05) urinary kallikrein (3.3 EU/24 h with creatinine clearance of 63.6+/-2.0 for 24 black patients and 4.2+/-0.7 EU/24 h with creatinine clearance of 67.0+/-3.5 for 6 white patients). These results suggest that a reduction in urinary kallikrein excretion rate is an early accompaniment of hypertensive renal injury. Urinary kallikrein excretion in response to a 6-d 10-meq sodium diet and a 3-d Florinef (0.5 mg b.i.d.) administration was compared in hypertensive patients with normal renal function vs. race and age-matched normal subjects. Stimulation of urinary kallikrein excretion by Florinef was equal in black and white normal subjects vs. hypertensive patients (black normals = 12.3+/-2.7 [n = 9], NREH = 11.7+/-1.8 [n = 10], LREH = 10.9+/-1.5 [n = 12]; white normals = 21.2+/-2.9 [n = 11], essential hypertension = 20.9+/-3.2 [10 NREH, 5 LREH]). Stimulation of urinary kallikrein excretion with low sodium diet was decreased (P < 0.05) only in black LREH (black normals = 11.2+/-2.4 [n = 10], NREH = 10.1+/-2.7 [n = 10], LREH = 7.4+/-1.1 [n = 13]; white normals = 19.1+/-2.7 [n = 13], essential hypertension = 17.5+/-2.3 [nine NREH, four LREH]). However, during low sodium diet, black patients with LREH had evidence for less sodium depletion as manifested by a decreased rise in urinary aldosterone excretion (16.3+/-2.7 vs. 33.3+/-6.4 mug/24 h for black normals) and a failure to achieve metabolic balance in 11/13 patients. Thus, the lesser kallikrein stimulation appeared to result from these two factors. Black and white hypertensives with creatinine clearance <80 ml/min had little increase in urinary kallikrein excretion with Florinef or low sodium diet.5 of 12 patients with primary aldosteronism or 17alpha-hydroxylase deficiency did not have an elevated urinary kallikrein excretion rate. Mild renal insufficiency may have contributed to this finding in two of these five patients. Nevertheless, this finding illustrates a limitation to the use of urinary kallikrein excretion rate as an index of mineralocorticoid activity. However, it appears that the majority of patients with LREH have no evidence for excess production of an unknown mineralocorticoid. The failure to find a decrease in urinary kallikrein excretion in racially matched patients with essentil hypertension and normal renal function questions the postulate of a role of the kallikrein-kinin system in the initiation of essential hypertension.

A biotype of Enterobacteriaceae intermediate between Citrobacter and Enterobacter.

The authors isolated two strains of an unnamed bacterial biotype with characteristics intermediate between those of Enterobacter and Citrobacter. The organisms did not produce acetyl-methyl carbinol, but decarboxylated lysine. Apart from the latter trait, they most closely resemble H2S-negative Citrobacter freundii. They differ biochemically from all other currently accepted species of enterobacteriaceae. Their pathogenic significance appears similar to that of the two genera they most closely resemble. Only by recognition and study of additional strains can their identity be more definitively delineated and their significance more fully assessed.

Late deoxyribonuclease activity of Salmonell enteritidis.

As a result of chance observations, the authors studied for deoxyribonuclease activity 16 strains of Salmonella, including six fresh isolates and ten stock cultures, with positive results in 13. Reactions characteristically occurred at 48 hours or later, with the majority being manifest at 72 hours and the latest at six days. No other positive reaction was observed among approximately 7,000 Enterobacteriaceae tested, except for Serratia species and Proteus vulgaris. Deoxyribonuclease screening plates for Serratia should be read at 24 hours, and positive results encountered after that time should be interpreted with caution to ensure that H2S-negative strains of Salmonella will not be confused with other genera of Enterobacteriaceae.

Identification of Proteus morganii and distinction from other Proteus species.

The identification of Proteus morganii in the clinical laboratory is complicated by the differences in incidence of hydrogen sulfide (H2S) production recorded by different sources. Since this quality appeared to be a frequent feature of strains of P. morganii at the author's center, all isolates of this species were studied over a six-month period. During this time, 12 of 21 were found to produce scant H2S in Kligler's iron agar (KIA) and triple-sugar iron (TSI) agar butts. The strains were, in every respect, biotypical, and were easily distinguished from other species of Enterobacteriaceae by biochemical study. They also possessed the features of high resistance to cephalothin and ampicillin and relative sensitivity to tetracycline, unlike strains of Proteus mirabilis. It is concluded that weak H2S production in TSI or KIA medium is a frequent normal characteristic of P. morganii, and its presence should not deter microbiologists from correctly identifying isolates manifesting this quality.

Hydrogen sulfide-producing Citrobacter diversus. A re-emphasis of the potential ability of all Enterobacteriaceae to manifest this quality.

Among 68 strains of Citrobacter diversus isolated in a community hospital in a year and a half, six were characterized by late H2S production in iron-agar slants, while otherwise typical. Although not recorded in standard tabulations, the potential for Enterobacteriaciae to develop this quality by plasmid transfer appears to be virtually unlimited, and dictates caution in the use of failure to produce H2S as a criterion for exclusion. In the present group, the use of the adonitol reaction as a means of distinguishing these organisms from more typical H2S producers is emphasized.