SUPERINFECTION: A COMPLICATION OF ANTIMICROBIAL THERAPY AND PROPHYLAXIS

Antibiotic therapies in maxillofacial surgery in the context of prophylaxis

OBJECTIVES

There is no single pattern for preventive action as to the duration and type of antibiotic therapy in maxillofacial surgery. In these circumstances, it appears reasonable to set relevant standards for prophylactic procedures after such surgeries.

METHODS

Retrospective analysis of bacteriological tests has been carried out as well as a susceptibility evaluation of cultured bacterial and fungal strains to antibiotics over a five-year period in subjects treated at the Cranio-Maxillo-Facial Clinic in Katowice. A total of 726 bacterial and fungal strains were cultured in 484 patients (200 women and 284 males). The age of the patients was 40.2 on average.

RESULTS

The most frequent bacteria isolated from the patients were Gram-positive 541 (74.5%). Gram-negative bacteria were present in 177 (24.4%) cases. Fungi of the Candida genus were isolated in eight cases (1.1%).

CONCLUSIONS

The most often isolated bacteria were Streptococcus mitis and Streptococcus oralis, whose number has grown over the last two years. Empiric therapies should be based on ciprofloxacin and gentamicin. It has been observed that all the Gram-positive bacteria are becoming more resistant to all antibiotics. Ampicillin and imipenem were antibiotics with the steepest resistance reduction while vancomycin showed the lowest resistance drop.

Infections in craniofacial surgery: a combined report of 567 procedures from two centers

This retrospective review of infectious complications was undertaken at two craniofacial centers (Dallas and Philadelphia). Fourteen infections were identified over a 6.5-year period in 567 intracranial procedures primarily for craniosynostosis. There were no infections in infants under 13 months of age and no cases of meningitis. The overall infection rate was 2.5 percent, and 85 percent of infections occurred in secondary reoperative cases. Tracheostomies were not identified as a risk factor for infection. No difference was found in infection rates between patients with shaved and unshaved scalps. Candida and Pseudomonas were the two most common organisms identified, and 28 percent of our infections involved yeast. The average time to diagnose infection was 11.5 days (excluding three patients who averaged 5 months). Thirteen of the fourteen infections were treated surgically with placement of a subgaleal irrigation/drainage system. Initial bony debridement was kept to a minimum. Based on our findings, recommendations are made to further lower infection rates, particularly those caused by opportunistic organisms.

Bacterial wound colonization after broad-spectrum versus narrow-spectrum antibiotics

Broad-spectrum versus narrow-spectrum antibiotic prophylaxis for patients who undergo cardiac operations is variously advocated to reduce the incidence of all infections or, conversely, to prevent resistant superinfections. Previous studies of prophylaxis have shown a reduction in the incidence of staphylococcal infections with some increased resistance. We studied preoperative and postoperative wound colonization as a surrogate for infection. Among 78 patients undergoing cardiac procedures, the type of prophylaxis was allocated as follows: narrow-spectrum (nafcillin), 24 patients; midspectrum (cephapirin), 26 patients; and broad-spectrum (ceftriaxone), 28 patients. Seventeen patients who underwent other procedures received no antibiotics and served as controls. Cultures of the operative site were done preoperatively, and 3 and 6 days postoperatively. The incidence of preoperative skin colonization with staphylococci was identical (95%) in all groups. Postoperatively, more patients receiving nafcillin (48%) were culture-negative for all organisms than were either of the other groups receiving antibiotics (27% and 22%) (p < 0.05). Gram-negative bacilli were infrequent colonizers and neither did the incidence of infection with these organisms increase nor did resistance develop in any group. The infection rates were not different among the treatment groups. Thus, a narrow-spectrum antistaphylococcal penicillin may offer an advantage in terms of both prophylaxis for cardiac operations and hospital costs.

Umbilical artery catheterization in newborns. II. Infections in relation to catheterization

Infections, as a complication of umbilical artery catheterization, were studied in 65 sick newborn infants. Every second day during the catheterization period peripheral blood cultures as well as blood samples for white cell count and platelets were taken. Cultures were taken from the catheter tips and from the umbilicus at the time of withdrawal of the catheter. Local or systemic antibiotics were not used prophylactically, but on rather broad clinical indications. No case of septicemia was found, but 8 infants had positive blood cultures and 16 had positive catheter tip cultures. Positive catheter tip culture occurred more often in infants who were born before 32 weeks of gestational age. Neither the duration of the catheterization nor the treatment with antibiotics influenced significantly the frequency of positive cultures.

Prophylactic use of antibiotics in surgery

"Sound and careful surgery is the sine qua non of wound management; antimicrobials are adjunctive." The key to successful use of prophylactic antibiotics in surgery is careful selection of cases and medication. There are no final rule or formulas that will always give optimal results. Listed below are some guidelines that may assis the clinician in determining the need and form of antimicrobial use. 1. The operation must carry a significant risk of bacterial contamination. Refined-clean and clean procedures should not be given prophylactic antibiotics. 2. Bacterial cultures should be taken when possible, and the medication used for prophylaxis should be effective against the organisms expected to be encountered. 3. Narrow spectrum antibiotics should be used to conserve the body's normal flora. Broad spectrum antibiotics needed to combat resistant infections should not be used for prophylaxis. 4. The antibiotic should be present in the wound in effective concentrations at the time of the incision and be maintained only as long as the risk of new bacterial contamination exists.

Risk of infection associated with umbilical vein catheterization. A prospective study in 75 newborn infants

To determine the risk of infection created by catheterization of the umbilical vein per se, 75 jaundiced, but otherwise healthy, newborn infants subjected to exchange transfusion were studied. Twenty-three were given antibiotics because of premature rupture of membranes. Fifty-three percent of the umbilici were contaminated before the insertion of the catheter, even after a very careful cleansing procedure. Sixty-two percent of the catheters were colonized upon removal. Bacteria were isolated from 44.9% of blood specimens drawn via the catheter at the onset of ET, but only in 14% of blood specimens drawn in the same way at the end of the procedure. Seven newborn infants (10%) were found to be bacteremic 4-6 after ET; four of these infants were not treated and were able to eliminate the bacteremia. Systemic antibiotic therapy did not reduce the overall prevalence of colonization of cord and catheter of positive blood cultures pre- and postexchanges transfusion or the rate of bacteremia.