Olli-Pekka Lehtonen

Elimination of Epidemic Methicillin- Resistant Staphylococcus aureus from a University Hospital and District Institutions, Finland

From August 1991 to October 1992, two successive outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) occurred at a hospital in Finland. During and after these outbreaks, MRSA was diagnosed in 202 persons in our medical district; >100 cases involved epidemic MRSA. When control policies failed to stop the epidemic, more aggressive measures were taken, including continuous staff education, contact isolation for MRSA-positive patients, systematic screening for persons exposed to MRSA, cohort nursing of MRSA-positive and MRSA-exposed patients in epidemic situations, and perception of the 30 medical institutions in that district as one epidemiologic entity brought under surveillance and control of the infection control team of Turku University Hospital. Two major epidemic strains, as well as eight additional strains, were eliminated; we were also able to prevent nosocomial spread of other MRSA strains. Our data show that controlling MRSA is possible if strict measures are taken before the organism becomes endemic. Similar control policies may be successful for dealing with new strains of multiresistant bacteria, such as vancomycin-resistant strains of S. aureus.

Antimicrobial systems of human whole saliva in relation to dental caries, cariogenic bacteria, and gingival inflammation in young adults

The association of salivary antibody (total IgA, IgG, and IgM and antibodies reactive with Streptococcus mutans) and non-antibody (lysozyme, lactoferrin, salivary peroxidase, myeloperoxidase, hypothiocyanite, thiocyanate) defense factors with oral health (past and present dental caries, gingival bleeding, the number of salivary S. mutans and lactobacilli) were studied in 50 naval recruits. Dental caries was significantly associated with large amounts of S. mutans, lactobacilli, and total salivary immunoglobulins and with low salivary flow rate and buffer capacity. Salivary anti-S. mutans antibodies did not correlate with dental caries or S. mutans levels. Moreover, none of the salivary non-antibody factors alone had any strong relationship to dental caries or S. mutans levels. Gingival inflammation was associated with elevated levels of lysozyme in whole saliva. It is concluded that in adults the associations between single-point measurements of most salivary antimicrobial constituents and the factors describing oral health are weak.

Aspergillus antigen in serum, urine and bronchoalveolar lavage specimens of neutropenic patients in relation to clinical outcome.

We have used a new, commercial enzyme-linked immunosorbent assay (ELISA, Platelia® Aspergillus) to detect Aspergillus antigen in serum, urine and bronchoalveolar lavage (BAL) samples of 105 haematological patients who received empirical amphotericin B treatment for suspected fungal infection. 14% (60/419) of serum and 5% (18/373) of urine samples were positive. Ten-fold concentration of urine increased the number of positive samples to 31 (8%). The antigen was detected in 5 of 20 BAL samples, but fungal culture was negative in all of them. 22 patients had positive antigen test. Serum was positive in 17, urine in 7 and concentrated urine in 12 patients. Six patients had confirmed invasive aspergillosis. In all these patients, antigen was detected in serum, but urine was positive in only 2 patients. Patients whose antigen test turned negative during the amphotericin B treatment had significantly lower mortality than patients with persistently positive antigen test (2/10 vs. 8/8, p=0.002). We conclude that Aspergillus galactomannan can be detected by ELISA in serum, urine and BAL samples of haematological patients, but the higher sensitivity of serum testing makes it preferable for screening. Disappearance of the antigen during antifungal therapy seems to correlate with good, and persistence with poor, clinical outcome.We have used a new, commercial enzyme-linked immunosorbent assay (ELISA, Platelia Aspergillus) to detect Aspergillus antigen in serum, urine and bronchoalveolar lavage (BAL) samples of 105 haematological patients who received empirical amphotericin B treatment for suspected fungal infection. 14% (60/419) of serum and 5% (18/373) of urine samples were positive. Ten-fold concentration of urine increased the number of positive samples to 31 (8%). The antigen was detected in 5 of 20 BAL samples, but fungal culture was negative in all of them. 22 patients had positive antigen test. Serum was positive in 17, urine in 7 and concentrated urine in 12 patients. Six patients had confirmed invasive aspergillosis. In all these patients, antigen was detected in serum, but urine was positive in only 2 patients. Patients whose antigen test turned negative during the amphotericin B treatment had significantly lower mortality than patients with persistently positive antigen test (2/10 vs. 8/8, p = 0.002). We conclude that Aspergillus galactomannan can be detected by ELISA in serum, urine and BAL samples of haematological patients, but the higher sensitivity of serum testing makes it preferable for screening. Disappearance of the antigen during antifungal therapy seems to correlate with good, and persistence with poor, clinical outcome.

Alcohol abuse: A risk factor for surgical wound infections?

BACKGROUND The incidence of postoperative surgical site infections (SSIs) is difficult to estimate because of the current trend of early discharge after surgery. Both operation-related and host factors should be taken into consideration in the prevention of SSIs. We wanted to determine the actual incidence of SSIs and evaluate the risk factors in our clinic, using an extended follow-up period of 30 days after operations. METHODS We performed a prospective follow-up survey of SSIs over a 3.5-month period including a 1-month follow-up after discharge with written instructions and a telephone survey. The SSIs were defined according to Centers for Disease Control and Prevention criteria. Forty-three patient parameters were recorded, and risk factors for SSI were sought and tested by using multiple logistic regression analysis. RESULTS The follow-up was completed in 772 of 807 patients. The SSI rates in these patients were 5.3% in clean, 7.1% in clean-contaminated, 6.2% in contaminated, and 28.1% in dirty operations. Seventy-one percent of infections were not diagnosed until after discharge from the hospital. According to multiple logistic regression analysis, alcohol abuse (p < 0.0001), wound contamination class (p < 0.05), and operation duration of over 2 hours (p < 0.05) were independently significant risk factors for SSI. CONCLUSIONS A major portion of SSIs are found only after follow-up is extended during the postdischarge period. Alcohol abuse is a significant risk factor for SSI and should be taken into account when determining the susceptibility of an individual patient.

Rhinovirus in Otitis Media with Effusion

We studied rhinovirus in the middle ear fluid of 61 children with subacute or chronic otitis media with effusion. Rhinovirus was recovered from the middle ear fluid of 5 children with subacute otitis media with effusion. The minimum duration of effusion was 32 to 60 days. Additionally, 1 patient had middle ear fluid that was positive for adenovirus. Bacterial pathogens were cultured from the middle ear fluid of 20 of 61 patients. Our finding that rhinovirus can be isolated from middle ear fluid after an asymptomatic period of several weeks suggests its possible role in the development of otitis media with effusion.

Antimicrobial Therapy of Septicemic Patients in Intensive Care Units before and after Blood Culture Reporting

68 cases of positive blood cultures from 54 intensive care unit (ICU) patients were analyzed retrospectively. The empiric antimicrobial therapy was correct in 65% of the cases as judged by the species and sensitivity of the blood culture isolate. After initial Gram-staining results were known, coverage increased to 77%. After the final blood culture results the coverage was still only 81%. The bacteremia-related mortality was 13%. Although there was no significant difference between the occurrence of bacteremia-related and non-bacteremia-related deaths either in patients with correct or non-optimal empiric treatment, this study emphasizes the need for better utilization of culture reporting. A considerable part of the final blood culture results went unnoticed by the ICU physicians which stresses the importance of good communication between the laboratory and wards.

DTP and DTP-inactivated polio vaccines: comparison of adverse reactions and IGG, IGM and IGA antibody responses to DTP.

Abstract. Ruuskanen, O., Viljanen, M. K., Salmi, T. T., Lehtonen, O.‐P., Kouvalainen, K. and Peltonen, T. (Departments of Paediatrics and Medical Microbiology, University of Turku, and Department of Paediatrics, University of Oulu, Finland). DTP and DTP‐inactivated polio vaccines: comparison of adverse reactions and IgG, IgM and IgA antibody responses to DTP. Acta Paediatr Scand, 69:177, 1980.—Adverse reactions and anti‐DTP antibody responses were compared between DTP‐ or DTP‐inactivated‐polio‐vaccinated children. The material consisted of 380 children whose adverse reactions were registered by detailed questionnaires given to the parents. IgG‐, IgM‐ and IgA‐anti‐DTP antibodies of 42 children were quantified using enzyme‐linked immunosorbent assay (ELISA). Fever, restlessness and local reactions were the most frequent adverse reactions observed. DTP‐polio vaccine induced significantly more restlessness than DTP. This was the only significant difference in adverse reactions between the vaccines. An enhancement of IgG‐anti‐DTP antibody responses at the age of 6 months was observed in the DTP‐polio group. The enhancement was transient in antitoxin responses but still present in pertussis antibodies at 8 months of age. Very low and mostly undetectable levels of IgM‐ and IgA‐anti‐DTP antibodies were observed in both groups.

A binding function for curve-fitting in enzyme-linked immunosorbent assay (ELISA) and its use in estimating the amounts of total and high affinity antibodies

Abstract A binding function was used to characterize the dose-response curves in an enzyme-linked immunosorbent assay (ELISA) for rabbit anti -hapten IgG antibodies. This curve-fitting procedure gave absorbances which deviated about 10% from the experimental absorbances. The method enables one to estimate antibody quality and quantity in large scale antibody measurement.

Early Candida isolations in febrile patients after abdominal surgery.

The significance of finding Candida sp. in febrile patients after abdominal surgery was studied in a prospective study on 107 patients. The patients were divided into 3 groups, based on the isolation and time of sampling of Candida sp. and on any other microbiological documentation of the infection. Eight patients were found Candida-positive either by blood cultures or by cultures of urine, abdominal pus, tracheal aspirate or wound exudate within the first postoperative week and had significantly greater mortality than patients with other infections or later Candida sp.-isolation (50% vs 10%, p < 0.05). Isolation of Candida was associated with prolonged antibiotic therapy, extended central vein catheterization, parenteral nutrition and operations on the small bowel, ascending colon or pancreas, but not with the underlying illness. The results support the view that isolation of Candida sp. within the first week after surgery does not represent harmless colonization but is rather associated with serious morbidity.

Yeasts in blood cultures: impact of early therapy

Patients with growth of yeast in blood cultures were analyzed during the 6-year-period 1981-1986, with special regard to predisposing factors, mortality, severity of the disease and therapy. There were 80 isolations of yeasts in blood cultures in 39 patients and Candida albicans was the most common. The majority of the patients in the material had multiple predisposing factors. The overall mortality was 58%. Patients with d disseminated disease had a mortality of 79% in contrast to 32% in patients with transient fungemia. Disseminated disease was more common in surgical patients. The prognosis of patients treated within 4 days from the onset of septic symptoms was significantly better than that of patients with a later start of therapy. On the basis of these results we emphasize the importance of early empiric therapy.