Leigh G. Donowitz

High risk of hospital-acquired infection in the ICU patient

Patients admitted to the ICU have a higher risk of nosocomial infection than other hospitalized patients. Whereas general medical/surgical ward patients have a 6% overall risk of acquiring an infection during their hospital stay, critically ill patients in the ICU have an 18% risk (p < 0.001). During this 2-year study, 440 of 2441 patients admitted to an ICU developed nosocomial infections. Patients who had prolonged ICU stays and those on the obstetrics and gynecology, orthopedics, and general surgery services were more likely to become infected. The most common bloodstream pathogens were Staphylococcus epidemidis, Staphylococcus aureus, and Serratia and Pseudomonas species.

The inanimate environment of an intensive care unit as a potential source of nosocomial bacteria: evidence for long survival of Acinetobacter calcoaceticus.

Environmental surface and personnel hand impression cultures were obtained during 13 sampling periods in the University of Virginia Pediatric Intensive Care Unit to document potential reservoirs of nosocomial pathogens. In 78 environmental cultures Staphylococcus aureus was found eight times and gram-negative bacilli ten times. The patient chart cover was the most commonly contaminated surface. Acinetobacter calcoaceticus was found in five of ten cultures positive for gram-negative bacilli. Thirty of 59 hand cultures were positive for S aureus and gram-negative bacilli; nurses and residents had both, respiratory therapists only gram-negative bacilli, and A calcoaceticus was the most commonly isolated bacterium of potentially nosocomial significance (14/30). Laboratory investigation of bacterial survival revealed that gram-negative bacilli survived on a dry formica surface from a few hours up to three days but Acinetobacter survived up to 13 days. Since A calcoaceticus has been implicated in many nosocomial infections, its long survival on a dry surface may be an additional factor in its transmission in hospitals and suggests that more attention be paid to environmental surfaces as a source of significant nosocomial pathogens.

Alteration of Normal Gastric Flora in Critical Care Patients Receiving Antacid and Cimetidine Therapy

One hundred fifty-three critical care patients with documented cimetidine and antacid use were prospectively studied with serial gastric pH determinations and semiquantitative gastric fluid cultures. This study documents the abnormal gastric colonization of patients with therapeutically altered gastric acidity by hospital acquired gram negative rods (GNR). Three hundred twenty-four gastric fluid cultures from 153 patients revealed 152 (47%) positive cultures for GNR, 78 (24%) sterile specimens, and 94 (29%) positive for mixed oropharyngeal flora. One hundred forty (59%) of the 236 cultures at a pH of 4 or greater were positive for GNR. In contrast, only 12 (14%) of the 88 cultures at a pH of less than 4 were positive for GNR (p less than .001). Forty-six (52%) of 88 cultures at a pH of less than 4 were sterile as compared to only 32 (14%) of 236 sterile cultures at a pH of 4 or greater (p less than .001). At low pH, cultures are predominantly sterile and at a pH of 4 or greater the flora dramatically changes to hospital acquired GNR. This artificially maintained reservoir of gram negative rods in the critically ill patient is a potential reservoir of organisms causing nosocomial bacteremia or pneumonia in this high risk population.

Hospital-acquired urinary tract infections in the pediatric patient: A prospective study

To determine through a prospective study the characteristics of hospital-acquired urinary tract infections (HAUTI) in children, 525 children subjected to bladder catheterization during a hospital admission were identified through surveillance of 12,316 admissions during a 24-month period. Urine culture results were available for 296 (56.4%) of the catheterized patients. In addition 12 noncatheterized children with a documented HAUTI were identified. The clinical courses of all patients with a HAUTI were followed for at least 6 months after their last HAUTI during the study period. Forty-four patients, 1 week to 17 years of age, with 1 or more HAUTI during a hospital unit admission were identified. A total of 51 HAUTI occurred. Thirty-nine (76.5%) of the infections occurred in patients subjected to catheterization. Thirty-two (10.8%) of 296 catheterized patients developed a HAUTI. Forty-three (84.3%) of the 51 infections were single organism infections. One HAUTI was associated with a wound infection with the same organism and one with a concurrent bacteremia with the same organism. Relapses were seen after 4 HAUTI. One reinfection was identified. There were no deaths directly associated with a HAUTI. Hospitalized children subjected to urinary tract catheterization are at significant risk for HAUTI. Complications are infrequent and not life-threatening.

High risk of nosocomial infection in the pediatric critical care patient

During this one-year prospective study, 61 (13.7%) of 444 patients admitted to the pediatric ICU at the University of Virginia Hospital developed nosocomial infections. By comparison, general medical/surgical ward patients had an overall 4.8% risk of acquiring an infection during their hospital stay. Patients who had prolonged ICU stays and those on plastic surgery, neurosurgery, and pediatric surgery services were more likely to become infected. The four bloodstream pathogens isolated in five episodes of hospital-acquired bacteremia were Staphylococcus epidermidis, S. aureus, Escherichia coli, and Serratia liquifaciens.

Neonatal intensive care unit bacteremia: Emergence of gram-positive bacteria as major pathogens

An outbreak of nosocomial Staphylococcus epidermidis bacteremia in a neonatal intensive care unit in 1981 was epidemiologically linked to use of Broviac central venous catheters (p = 0.05) and prompted a review of nosocomial infection surveillance data for the previous 6 years, which indicated a striking shift from gram-negative to gram-positive bacteria, especially coagulase-negative staphylococci, as major bloodstream pathogens. In a case-control study with 68 patients with bacteremia between 1979 and September 1981 and 64 control patients, stratified by birth weight, three risk factors were identified: use of Broviac central venous catheters, surgical procedures, and intravenous hyperalimentation. The risk factors varied with the birth weight category. In the group of cases and controls with birth weights less than 1500 gm, only the use of Broviac catheters, which are usually left in the superior vena cava for several weeks, was associated with subsequent bacteremia (odds ratio = 7.1, p = 0.001). These observations, as well as the temporal association of the introduction of Broviac catheters with the subsequent shifts in causes to gram-positive organisms, suggest that the long-term indwelling vascular access devices contributed greatly to the changing pattern.

Intravascular Catheter Colonization and Related Bloodstream Infection in Critically III Neonates

Intravascular catheter tip colonization was prospectively evaluated in critically ill neonates to determine its relationship to the type of device used, duration of catheterization, insertion site and nosocomial bloodstream infection. Sixty-one percent (376 of 621) of all intravascular catheter tips were retrieved from 91 infants. Thirteen percent (41 of 310) of peripheral intravenous, 14% (6 of 42) of umbilical, 21% (3 of 11) of central venous, 36% (4 of 11) of peripheral arterial and 100% (2 of 2) of femoral catheters were colonized. Duration of catheterization was significantly longer for colonized lines (p less than .001). Eight of 26 (30.8%) peripheral intravenous catheters remaining in place for more than three days were colonized, compared with 33 of 284 (11.6%) at three days or less (p = 0.012). Coagulase-negative staphylococcus was the organism most frequently isolated from catheter tips and bloodstream infections. Catheter colonization rates in this population were higher than those found in adults. Heavily manipulated devices and those in place for longer periods of time were the most frequently colonized.

Paecilomyces lilacinus infection in a child with chronic granulomatous disease

Chronic granulomatous disease (CGD) is a rare inherited disorder in which neutrophils do not appropriately generate cytotoxic superoxide anion, the respiratory burst, in response to invading bacteria or fungi as a part of normal host defence. We report the case of a child with CGD who had two abdominal wall abscesses caused by Paecilomyces lilacinus, an organism not previously known to cause infections in patients with CGD. The abdominal wall is a location that is rarely associated with Paecilomyces infections. Parenteral amphotericin B eradicated the infection in an immunocompromised child whereas this regimen has heretofore largely been unsuccessful in the treatment of this infection. Paecilomyces species and other fungi from immunocompromised hosts and thought to be laboratory contaminants, need to be carefully investigated for they may become pathogens in this clinical setting.

Endometritis following cesarean section: A controlled study of the increased duration of hospital stay and direct cost of hospitalization☆

The increased hospital stay and direct costs of hospitalization as a result of postcesarean section endometritis were evaluated in a case-matched and controlled study (N = 20 in each group). Endometritis increased postcesarean section hospital stay by 3 days and increased hospital cost by

Nesocomial infection in neonatal intensive care units

850. Fifteen to 20% of women delivered by cesarean section develop postpartum endometritis. The success of future antibiotic or surgical intervention studies in reducing this high complication rate can be more accurately evaluated by comparison with these now established parameters of morbidity and cost.