Outbreak Of Extended-spectrum Beta-lactamase Research Articles

Extended-spectrum β-lactamase-producing Enterobacter cloacae in mobile dialysis units in the medical and surgical departments of a university hospital: a case–control study

The objective of this case-control study was to investigate the source of contamination and risk factors for colonisation and infection during an outbreak of extended-spectrum beta-lactamase (ESBL)-producing Enterobacter cloacae in the University Medical Center Freiburg. A risk factor analysis was performed on 23 patients with ESBL-producing E. cloacae in the medical and surgical departments by comparing them with 46 non-colonised controls, who were matched for ward and length of hospital stay. For these, a risk factor analysis was conducted. Suspected sources for transmission of ESBL were examined and staff received training in infection control measures. The higher risk in colonised patients was attributed to dialysis with mobile units [odds ratio (OR): 4.00; 95% confidence interval (CI): 1.05-15.234; P=0.04]. Dialysis units were examined, but no contamination was found. Improvement in dialysis procedures, additional staff training and renewed training in standard precautions led to a substantial fall in case numbers. Risk factor analysis showed that colonised patients carried more invasive devices than controls (central venous catheter: OR: 2.50; 95% CI: 0.74-8.45; P=0.14; Foley catheter: 5.08; 0.61-42.23; P=0.13) and were given a greater number of different antibiotics (penicillins: 2.52; 0.71-8.89; P=0.15; fluoroquinolones: 2.37; 0.77-7.28; P=0.13). The differences in mobile dialysis frequency and antibiotic use between cases and controls were relevant, although the latter was not statistically significant. It was possible to contain the high frequency of ESBL colonisation or infection by reinforcing infection control measures and training the staff involved.

Clinical Characteristics of Extended-spectrum β-lactamase Producing Shigella sonnei Infection Outbreaked in Chungju Area

An outbreak of extended-spectrum beta-lactamase (ESBL)-producing Shigella sonnei enteritis, especially in pediatric populations, was unprecedented not only in Korea, but also throughout the world in the past. This study was intended to devise a management guideline for shigellosis caused by an ESBL-producing strain based on analysis of the clinical manifestations and response to therapy. We examined 24 strains of S. sonnei isolated from stool cultures of patients with acute enteritis, between November 2004 and February 2005, for antimicrobial susceptibility and ESBL production, and we also performed DNA sequencing with PCR for the typing of ESBL genes. In addition, we retrospectively analyzed the clinical characteristics, laboratory results, and therapeutic responses to antibiotics of the 103 patients who grew S. sonnei on stool cultures. All 24 isolates showed a very similar antibiotic sensitivity pattern and were ESBL gene type of CTX-M-14. The most frequent clinical symptom in the 103 patients was a fever, followed by diarrhea, abdominal pain, headache, vomiting, and nausea. Leukocytosis and CRP were positive in 53.4% and 78.6% of the patients, respectively. On stool direct smears, 11.7% showed more than 50 WBCs per HPF and 71% were positive on stool occult blood. Microbiological eradication rates were as follows: azithromycin and ciprofloxacin, 100%; imipenem-cilastatin, 68.8%; ampicillin-sulbactam, 42.9%; amoxicillin-clavulanic acid, 20%; ceftizoxime, 12.5%; cefdinir, 6.9%; and ceftriaxone and trimethoprim-sulfamethoxazole, 0%. We presumed that, given its cost-effectiveness and safety, azithromycin can be an attractive option for the treatment of ESBL-producing S. sonnei enteritis in pediatric populations. Although ciprofloxacin is another cost-effective agent, its use in pediatric populations is not recommended.

Outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a neonatal intensive care unit linked to artificial nails.

From April to June 2001, an outbreak of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae infections was investigated in our neonatal intensive care unit. Cultures of the gastrointestinal tracts of patients, the hands of healthcare workers (HCWs), and the environment were performed to detect potential reservoirs for ESBL-producing K. pneumoniae. Strains of K. pneumoniae were typed by pulsed-field gel electrophoresis using XbaI. A case-control study was performed to determine risk factors for acquisition of the outbreak clone (clone A); cases were infants infected or colonized with clone A and controls (3 per case) were infants with negative surveillance cultures. During the study period, 19 case-infants, of whom 13 were detected by surveillance cultures, harbored clone A. The overall attack rate for the outbreak strain was 45%; 9 of 19 infants presented with invasive disease (n = 6) or developed invasive disease (n = 3) after colonization was detected. Clone A was found on the hands of 2 HCWs, 1 of whom wore artificial nails, and on the designated stethoscope of a case-infant. Multiple logistic regression analysis revealed that length of stay per day (odds ratio [OR], 1.05; 95% confidence interval [CI95], 1.02 to 1.09) and exposure to the HCW wearing artificial fingernails (OR, 7.87; CI95, 1.75 to 35.36) were associated with infection or colonization with clone A. Short, well-groomed, natural nails should be mandatory for HCWs with direct patient contact