Hospital- and community-based surveillance of methicillin-resistant Staphylococcus aureus: previous hospitalization is the major risk factor.

OBJECTIVE: The purpose of the study was to determine the incidence and risk factors for the acquisition of methicillin-resistant Staphylococcus aureus (MRSA) in our community. DESIGN: This study used a cross-sectional design to assess patients colonized or infected with MRSA. PATIENTS: The study population consisted of residents of London, Ontario, Canada, who were identified as MRSA-positive for the first time in 1997. SETTING: All acute- and chronic-care hospitals, long-term healthcare facilities, and community physicians' offices in the city of London participated in the study. MAIN OUTCOME MEASURE: Incidence of MRSA in the community, risk factors for acquisition, especially previous hospitalization over a defined period, and strain type were evaluated. RESULTS: In 1997, 331 residents of London were newly identified as MRSA-positive, representing an annual incidence of 100/100,000 persons (95% confidence interval, 88.8-110.7). Thirty-one (9.4%) individuals were not healthcare-facility patients in the previous month, and 11 (3.3%), 10 (3.0%), and 6 (1.8%) individuals had no such contact in the previous 3, 6, and 12 months, respectively. One hundred seventy-seven strains, including five of the isolates from patients with no healthcare-facility contact in the previous year, were typed. One hundred sixty (90.3%) of these isolates, including all typed strains from patients with no healthcare facility contact, belonged to a single clone. CONCLUSION: These findings demonstrate that the incidence of MRSA is higher than previously reported and that hospital contact is the single most important risk factor for the acquisition of MRSA in our community. Screening for MRSA in previously hospitalized patients at the time of hospitalization may reduce nosocomial spread and indirectly reduce the incidence of MRSA in the community.

Surveillance and prophylactic intervention of Staphylococcus aureus nasal colonization in a hemodialysis unit.

Surveillance of 101 hemodialysis patients for Staphylococcus aureus positive nasal cultures was performed by monthly nasal swabs over a 27-month period. All positive cultures were treated with a prophylactic antibiotic regimen. Forty-seven (46.5%) patients had one or more positive cultures. The surveillance period was longer in the S. aureus nasal carriers (p = 0.004). The frequency of positive cultures correlated with the duration of surveillance (p = 0.029). The incidence of S. aureus bacteremia was greater in patients with two or more positive cultures (p = 0.030). This study suggests that continuous surveillance for S. aureus nasal colonization is essential to properly identify all patients at risk of developing S. aureus bacteremias.

Comparison of blood cultures with corresponding venipuncture site cultures of specimens from hospitalized premature neonates.

We compared the presence and identities of isolates from blood culture samples obtained by percutaneous venipuncture with those of commensal skin organisms cultured from respective venipuncture sites after skin cleansing; 677 blood and skin site culture pairs from 488 infants were compared. Organisms grew in 58 blood cultures; nine of these cultures had corresponding venipuncture site cultures that also grew organisms. Forty-two blood culture isolates were coagulase-negative staphylococci; five of these were associated with similar venipuncture site cultures. According to restriction-endonuclease fingerprinting of chromosomal DNA and plasmid analysis, three pairs of blood and venipuncture site cultures were identical and two pairs were different. Thus only 7% (3/42) of coagulase-negative staphylococcal blood isolates were associated with identical contamination at the venipuncture site. We conclude that, if the venipuncture site has been carefully cleansed, the growth of coagulase-negative staphylococci in blood cultures of specimens from premature neonates indicates bacteremia rather than skin contamination in the vast majority of cases.

Campylobacter associated gastritis in patients with non-ulcer dyspepsia: a double blind placebo controlled trial with colloidal bismuth subcitrate.

Fifty consecutive patients with non-ulcer dyspepsia and a Campylobacter associated gastritis (CAG) were randomly assigned to treatment with colloidal bismuth subcitrate (CBS) 240 mg twice daily or placebo, according to a double blind study design. After the blind treatment an 'open' treatment with CBS was started in both groups. Twenty six patients treated with CBS showed a significant reduction in colonisation with Campylobacter pylori and a significant improvement in the Whitehead gastritis score. No significant changes were recorded in twenty four patients treated with placebo. After an additional course of CBS no further improvement in gastritis score was noted but there was a further reduction in Campylobacter colonisation. CBS did not greatly alter subjective complaints. Subjective complaints were improved in both treatment groups except for nausea and meteorism that improved more in the CBS treated patients. This finding again questions the clinical significance of gastritis and also casts doubt on the clinical relevance of therapeutical measures aimed at eradication of C pylori.

Perinatal listeriosis underdiagnosed as a cause of pre-term labour?

Between April 1, 1985, and April 1, 1986, four cases of perinatal listeriosis were reported at the Maastricht Academic Hospital. All cases were of the early-onset type. All mothers were admitted for pre-term labour between 28 and 33 weeks of gestation. Pre-natal symptoms included maternal fever, non-characteristic influenza-like manifestations, leucocytosis and (pre-term) meconium-stained amniotic fluid. Two neonates died, one in utero and one due to listeriosis sepsis. Another neonate developed a hydrocephalus. Only one neonate has survived without damage up to now. Such a high incidence of listeriosis and the high perinatal morbidity and mortality rates are remarkable. Epidemiological, bacteriological and placental sequelae of Listeria monocytogenes are discussed.

Campylobacter associated gastritis in patients with non-ulcer dyspepsia.

Gastric biopsy specimens from 109 patients with non-ulcer dyspepsia were retrospectively examined. Sixty one patients had gastritis and there was a strong correlation with the presence of Campylobacter pyloridis. Ninety eight per cent were positive in large numbers for C pyloridis by histological examination or by culture, or both. Of 48 patients with normal histological results, 21 had evidence of C pyloridis by histological examination or culture, or both, but in small numbers. It is concluded that there is a quantitative rather than a qualitative association between C pyloridis and gastritis.