Laboratory diagnosis of congenital syphilis by immunoglobulin M (IgM) and IgA immunoblotting.

We screened cord blood or serum samples from 101 infants at risk for congenital syphilis and serum samples from their mothers for immunoglobulin G (IgG), IgM, and IgA antibodies to Treponema pallidum by western blotting (immunoblotting). Clinical evaluation showed that six infants had signs and/or symptoms consistent with congenital syphilis. The sera from five of these infants were IgM blot positive, and four were IgA blot positive. Four asymptomatic infants had serologic evidence of congenital syphilis. The sera from three of these infants were IgM blot positive, and two were IgA blot positive. However, the IgM reactivity of the serum from one asymptomatic infant, which was also IgA positive, was abolished by protein G treatment. An IgM capture enzyme-linked immunosorbent assay corroborated the presence of IgM antibodies in six of seven IgM blot-reactive sera. Overall, for detection of symptomatic congenital syphilis, a sensitivity of 83% for IgM blotting and 67% for IgA blotting was obtained. The significance of positive IgM or IgA Western blots for asymptomatic infants requires further study to confirm infection in these infants.

The use of quantitative bacterial counts in open fractures.

Late infections remain a significant complication in the treatment of open fractures, occurring in 2% to 25% of all open fractures. Recently there has been a trend toward early soft-tissue coverage of open fracture wounds. Quantitative bacterial counts have been used primarily by plastic surgeons to assess the viability of primary versus delayed wound closures. Quantitative bacterial counts were obtained in 52 consecutive open fractures in 50 patients to assess the correlation between quantitative bacterial counts and subsequent sepsis, to determine the effect of time to debridement on the quantitative bacterial count, and finally to review the bacteriology of open fractures. Forty-one of the 52 fractures had positive quantitative bacterial counts. Four of eight (50%) fractures with quantitative bacterial counts greater than 10(5) developed late sepsis, while only two of 44 (5%) with quantitative bacterial counts less than 10(5) or negative quantitative counts became infected. There was no correlation between time to debridement and quantitative bacterial count levels. A significant percentage of the positive quantitative bacterial counts were gram-negative organisms.

Comparison of immediate and delayed culture methods for isolation of group A streptococci.

Recovery rates of Group A beta-hemolytic streptococci in throat cultures from 300 children were studied using three different methods. The swabs were streaked onto plates immediately, streaked from the same dry swabs held at room temperature for 3 to 6 hours and streaked from swabs held in transport media at room temperature for 3 to 6 hours. The cultures were processed in a pediatric office and interpreted by a microbiologist. The recovery rates were similar for the three methods, but the cultures were easier to interpret when the swabs had been allowed to dry before streaking as a result of a decrease in the normal flora on these plates. In a separate study the recovery of Group A beta-hemolytic streptococci from 187 swabs was identical whether the swabs were streaked at 3 to 6 hours or at 18 to 24 hours.

Rapidly growing nontuberculous mycobacteria: a new enemy of the cardiac surgeon.

A review of atypical mycobacterial infections complicating cardiac operations is presented. Proven sources of infections at different institutions include contaminated porcine valves and municipal water supply, but the mode of transmission in the great majority of patients remains unclear. There are two principal clinical forms of atypical mycobacterial infections after cardiac operations--endocarditis and sternal osteomyelitis. The latter has characteristics resembling tuberculotic "cold abscess." Specialized laboratory testing is necessary to confirm the diagnosis, and surgeons may have to take the initiative to request special microbiological investigation in cases where infection is clinically suspected but routine cultures are reported as "negative." The prognosis for patients who have any atypical mycobacterial infection after a heart operation is severe. Those infected with the strain chelonei and those whose cardiac chambers were entered during operation fare worse. This dim clinical prognosis may be improved by appropriate and aggressive antibiotic and surgical therapy. Awareness of the urgency of special bacteriological studies is the key to successful management.

Two outbreaks of sternal wound infection due to organisms of the Mycobacterium fortuitum complex.

Two outbreaks of postoperative wound infections due to organisms of the Mycobacterium fortuitum complex (Mycobacterium chelonei and M. fortuitum) occurred among patients who underwent open-heart surgery. In one hospital, 19 of 80 patients who underwent cardiac surgery within a 10-week period developed sternal infection with M. chelonei. In the second hospital, four of nine patients who underwent cardiac surgery within a two-week period developed sternal incisional infection with M. fortuitum. Although epidemiologic investigations uncovered factors that were significantly associated with the development of infection, the source of the infections could not be determined. The results of numerous cultures were negative, but because the investigations were conducted at least two months after many of the patients had had surgery, the materials in use at the time of the surgery were not available for culture. These results emphasize that physicians should be aware that rapidly growing mycobacteria may produce postoperative wound infections.

Mycobacterium fortuitum epidemics after open-heart surgery.

We present the clinical and epidemiological features of Mycobacterium fortuitum epidemics involving 19 patients who underwent open-heart surgery. The source of the infection could not be identified. However, bone wax and homografts utilized at that time have been suspected. The infected patients responded poorly to antibiotic management and their courses in most cases were influenced beneficially by total sternectomy and transplantation of the omentum into the mediastinum. The emergence of M. fortuitum may represent an aggressive bacterial strain resistant to presently used broad-spectrum antibiotic drugs.

Apparent spontaneous induction of Staphylococcus aureus isolated from clinical sources.

Apparent spontaneous induction in staphylococcal strains from two clinical specimens was described. One of the two phages associated with these strains was found useful in typing otherwise untypable strains.

Identification of Corynebacterium diphtheriae by immunofluorescence during a diphtheria epidemic.

During a large epidemic of diphtheria, the technique of immunofluorescence was applied to specimens obtained from 310 patients, 77 of whom were diagnosed clinically as having the disease. The technique made use of commerical fluorescent antisera prepared against the somatic antigens of Corynebacterium diphtheriae. The results obtained by immunofluorescence of slides prepared directly from swabs were found to be unsatisfactory but when the swabs were subjected to prior incubation in a growth medium the results of immunofluorescence and bacterial culture agreed in 95% of specimens. Immunofluorescence applied to bacterial colonies obtained on primary isolation agreed completely with definitive bacterial identification. These two methods for the rapid identification of C. diphtheriae appeared to be as reliable as formal cultural and biochemical methods and could be usefully and economically applied to the examination of large numbers of clinical specimens during an epidemic.