A prospective microbiological surveillance (PMS) program was developed in a comprehensive hospital-wide effort for control of nosocomial methicillin-resistant Staphylococcus aureus (MRSA). This PMS program entailed: 1) active identification of colonized and infected patients; 2) application of a screening microbiologic system for MRSA; 3) isolation of colonized and infected patients; 4) antibiotic decolonization of MRSA; and 5) educational efforts. The PMS program was studied over three and one half years for its contribution to infection control of MRSA, early identification of nosocomial MRSA outbreaks, use of the highest yield surveillance culture sites, and cost effectiveness. Following initiation of the PMS program in December 1982, during an MRSA outbreak, the frequency of new MRSA cases declined from 14 to none by the end of a 3-month pilot study. The frequency of new MRSA cases stabilized at approximately 2 per month until October 1983, when the PMS system allowed prompt detection of a new outbreak of 11 cases. Following isolation and antibiotic decolonization, the frequency of cases again declined to 3 per month. A third outbreak in December 1985 again was promptly detected and controlled. Infection to colonization ratio decreased from a maximum of 1.5 during outbreaks to a minimum of 0.17 after outbreaks. Wounds and tracheostomy sites provided the greatest yield of detection of new cases of MRSA. During one 15-month period, 35 of the 43 new cases were detected initially at wounds and tracheostomy sites. No new MRSA cases were detected by a positive axillary or nares site alone. The estimated quarterly cost of outbreaks and infection paralleled the quarterly frequency of new MRSA cases. The cost of managing MRSA outbreaks and treating MRSA infections versus the cost of implementing the PMS program suggested that the PMS program may be cost effective. This prospective microbiological surveillance program may be applicable to other institutions for hospital-wide infection control of MRSA.

A methicillin- and rifampin-resistant strain of Staphylococcus aureus was introduced into a university hospital by interstate transfer of an infected surgical patient. An outbreak occurred, and 17 patients became infected or colonized with the epidemic strain. Reservoirs appeared to be patients who were infected or colonized with the resistant S aureus and possibly two nurses who were nasal carriers. The outbreak isolate was likely spread by contact with contaminated hands of personnel. A retrospective case-control study identified tracheostomy, debridement, and irrigation of wounds by power spray and prolonged nasogastric intubation as risk factors for acquisition of the epidemic strain. Analysis of factors by groups indicated that surgical procedures, wound care procedures and instrumentation of the respiratory tract were significantly associated with cases. The nasal carrier state was eradicated in two nurses by topical application of 5% vancomycin. The epidemic strain was eradicated from the hospital 8 months after it was introduced.

During a 13-month period, 25 residents of a nursing home were found to have positive cultures for methicillin-resistant Staphylococcus aureus (MRSA), including 17 with clinically significant infections. The outbreak came to attention in February 1985 when pneumonia was diagnosed in five residents during a 10-day period, and sputum cultures from all five were positive for MRSA. A survey revealed that nine (12%) of a sample of 74 residents and nine (7%) of 130 personnel had positive cultures for MRSA. Six of nine residents with MRSA detected in the culture survey had not been hospitalized for 6 or more months before the survey, suggesting acquisition of MRSA in the nursing home. Implementation of control measures was associated with a decreased occurrence but not complete elimination of new cases. MRSA in nursing homes is of concern because these institutions might serve as reservoirs for MRSA in the community. Further studies are required to define the magnitude of the problem, as well as optimal control measures.

During a 6-month period, term infants underwent nasal and umbilical swabbing within 96 hours of delivery and again at 1 to 18 (mean 3.8) weeks after discharge. Swabs were inoculated onto horse blood agar and all S aureus isolates were phage typed. Two hundred three infants were enrolled and follow-up was obtained for 181 (89%). Thirty-two of 181 (17.6%) were initially colonized, of whom 12 (37.5%) were colonized on follow-up. Thirty-two of 181 became colonized subsequent to hospital discharge. No single phage type predominated. Twenty-five patients were diagnosed to have clinical illness—omphalitis (11), conjunctivitis (10), and pustulosis (5). Six of these were colonized with 5 aureus initially, although organisms of the same phage type were not recovered from cultures obtained at the time of clinical illness. There was no significant difference in the rate of infections in colonized (19%) versus noncolonized (12%) infants. In five patients where S aureus was recovered at the time of symptoms, all organisms were acquired subsequent to discharge. We conclude that nursery colonization with S aureus did not lead to clinical illness, and clinical illnesse s previously ascribed to S aureus frequently occur in the absence of these bacteria.

Staphylococcus aureus continues to be a resilient and persistent problem for hospital infection control programs. Now methicillin-resistant S. aureus (MRSA) is emerging as an even more formidable foe, bringing with it controversies in laboratory reporting, treatment, and isolation strategies.

History suggests that the best solution to the hospital bacteria problem may well lie in the realm of spirit more than material methods. So, in the manner of Dickens' Christmas Carol fantasy, let us travel with three spirits— the Spirit of Conscience Past, the Spirit of Conscience Present, and the Spirit of Conscience to Come.

Resistance of most clinical pathogens to beta-lactam antimicrobial agents is currently primarily mediated by the microorganisms' ability to product beta-lactamases. There are a variety of beta-lactamases which are primarily differentiated by whether they are plasmid- or chromosome-mediated and by their substrate and inhibition profiles. The most common group of beta-lactamases produced by clinical isolates are the plasmid-mediated TEM enzymes (Richmond-Sykes type III a) which exist in many Enterobacteriaceae, Hemophilus influenzae, and Neisseria species. Development of new beta-lactam antimicrobial agents during the past decades has resulted in a number of drugs with increased, albeit not total, resistance to beta-lactamases. Another approach has been the development of beta-lactamase inhibitors that can be used with a beta-lactam drug to overcome the resistance created by the beta-lactamase.