During a ten-month period from September 1981 to July 1982 three episodes of pseudobacteremia due to Bacillus species occurred at this 550-bed institution. The first involved eight isolates, the second 11, and the third seven isolates of the organism, all with the same antibiogram.

The patients involved did not exhibit clinical signs of septicemia, and in only one case was more than one specimen per patient positive when multiple blood samples were obtained. Occasional blood cultures of Bacillus species identified in between clusters revealed a different antibiogram.

Extensive epidemiologic investigation of patient locations, phlebotomists, and time of cultures yielded no common source. Components involved in the transport and processing of blood cultures, including the radiometric blood culture processor, were also sampled but without recovery of the organism. After the last episode, a layer of dust was noted inside the machine, and culture of this dust grew Bacillus spp. with the same antibiogram as those found in the blood cultures. The filter from an air conditioning unit in close proximity to the machine grew several species of Bacillus.

It is presumed that Bacillus spores in the dust were introduced into the blood culture bottles following the heat sterilization of the gas sampling (inoculation/removal) needles.

Modification of the cover of the machine was undertaken to prevent access of dust bearing microbes to the inside of the machine. In addition, maintenance now includes regular disinfection/cleaning of the “floor” of the machine, and more frequent changes of the air conditioner filter.

Twenty-three episodes of pseudobacteremia occurring over a seven-month period were traced to cross-contamination by the automated blood culture analyzer (BACTEC 460) used in the microbiology laboratory. An epidemiologic investigation of an unusual cluster of three patients with pseudobacteremia caused by oxacillin-resistant Staphylococcus aureus led to the identification of the problem. Mock trials of the blood culture procedure confirmed that the blood culture analyzer was the source of contamination. After the needle sterilizer was replaced by the manufacturer, the problem of cross-contamination abated. Contamination of sterile blood cultures by an instrument intended to identify bacteremia rapidly may lead to incorrect diagnosis, unnecessary administration of antibiotics and prolonged hospitalization. Because of the widespread use of automated blood culture analyzers in the US, physicians, microbiologists, and infection control personnel should be alert to the possibility of cross-contamination and the subtle way in which it may present.

In April 1978, a strain of gentamicin-resistant Klebsiella pneumoniae (GRK) was introduced into the neonatal intensive care unit of Henry Ford Hospital. An additional ten cases of GRK occurred over the subsequent 16 months and intestinal colonization occurred in up to 91% of admissions per month. All GRK were susceptible to amikacin and were capsular serotype 19. Though hand contamination of hospital personnel with GRK was documented, increased handwashing practices did not reduce colonization rates of neonates with the epidemic strain. Intestinal carriage persisted for up to ten months and could not be eradicated by administering oral colistin sulfate. Discontinuation of gentamicin and utilization of amikacin were associated with a significant reduction in colonization with GRK (p < 0.05). However, the only control measure that prevented both new cases and colonization with the epidemic strain was the utilization of a strict cohort system.

Automated peritoneal dialysis systems have helped make intermittent peritoneal dialysis an alternative to hemodialysis for long-term management of patients with end-stage renal disease. However, if not cleaned and maintained properly, these machines provide a reservoir for pathogens. The microbiologic barriers in these machines are not impenetrable, but sterile dialy-sate fluid can be produced if the machines are adequately cleaned and disinfected. Potential shortcomings of the microbiologic barriers are discussed, and guidelines to prevent contamination of the internal parts of a machine are suggested.

The epidemiology of endemic gentamicin- and tobramycin-resistant gram-negative bacilli at a community hospital was analyzed over a one-year period three years following an original analysis at the same hospital. The frequency and distribution of resistant organisms remained stable over the time spanning the two studies. Only 2.8% of all gram-negative bacilli were resistant to gentamicin or tobramycin, and the majority of resistant isolates were non-Enterobacteriaceae. The respiratory and urinary tracts remained the body sites most prone to harbor resistant organisms. Risk analysis using a matched comparison group again revealed prior treatment with an aminoglycoside to be the only significant factor pre-disposing to acquisition of resistant gram-negative bacilli. This analysis indicates that community hospitals may not be important reservoirs of endemic aminoglycoside-resistant gram-negative bacilli, and reconfirms the observation that each hospital must define its own pattern of aminoglycoside resistance and unique risk factors.

In first examining the legal aspects of an antibiotic audit, it might be well to consider the legal basis or reason to do such an audit.

A hospital may be compelled to act in certain ways in order to comply with standards based on:

1. Federal laws

2. State laws, particularly those on hospital licensure.

3. Joint Commission on Accreditation of Hospitals (JCAH) standards if the hospital is JCAH accredited.

4. The hospital's own bylaws, rules and regulations, and policies and procedures.

5. Certain actions are also based on duties perceived from reading opinions in lawsuits. This even may be reflected in changes in the hospital's bylaws, rules and regulations, or policies and procedures.

The hospital is a unique workplace in terms of the infectious hazards it presents to its employees. Traditionally, infection control programs have focused on various aspects of infection control in patients. However, infections constitute a risk for health care workers, a fact which emphasizes the importance of infection control input into the employee health program. Many health care facilities and most regulatory agencies recognize the importance of infection control in health care workers. However, infection control programs have had varying degrees of influence in occupational health matters. As the discipline of infection control has grown and become more sophisticated, the subdiscipline of employee health has also begun to grow and emerge with a data base of its own. Many infection control conferences, symposia, and meetings now have a session or two related to employee health. Perhaps even more important is the CDC Guideline for Infection Control in Hospital Personnel, written by a CDC panel as part of its guidelines series. It will be responsible for drawing attention to employee health issues as they relate to infection control and should help solidify the discipline. The guideline will also provide opinions and answers to many questions regarding infection control and employee health.