Molecular typing of toxic shock syndrome toxin-1- and Enterotoxin A-producing methicillin-sensitive Staphylococcus aureus isolates from an outbreak in a neonatal intensive care unit.

Outbreaks of Staphylococcus aureus are common in neonatal intensive care units (NICUs). Usually they are documented for methicillin-resistant strains, while reports involving methicillin-susceptible S. aureus (MSSA) strains are rare. In this study we report the epidemiological and molecular investigation of an MSSA outbreak in a NICU among preterm neonates. Infection control measures and interventions were commissioned by the Local Public Health Authority and supported by the Robert Koch Institute. To support epidemiological investigations molecular typing was done by spa-typing and Multilocus sequence typing; the relatedness of collected isolates was further elucidated by DNA SmaI-macrorestriction, microarray analysis and bacterial whole genome sequencing. A total of 213 neonates, 123 healthcare workers and 205 neonate parents were analyzed in the period November 2011 to November 2012. The outbreak strain was characterized as a MSSA spa-type t021, able to produce toxic shock syndrome toxin-1 and Enterotoxin A. We identified seventeen neonates (of which two died from toxic shock syndrome), four healthcare workers and three parents putatively involved in the outbreak. Whole-genome sequencing permitted to exclude unrelated cases from the outbreak and to discuss the role of healthcare workers as a reservoir of S. aureus on the NICU. Genome comparisons also indicated the presence of the respective clone on the ward months before the first colonized/infected neonates were detected.

A prospective study on surgical-site infections in thyroid operation.

BACKGROUND: To evaluate the incidence and the microbe spectrum of surgical-site infections (SSIs) in patients undergoing elective thyroid operation and to develop a risk factor-based predictive model. METHODS: This prospective study included 6,778 consecutive patients who underwent thyroid operation at a single institution between 2007 and 2012. SSI was defined according to the Centers for Disease Control and Prevention. Regression models were fitted to evaluate risk factors for SSI. A predictive nomogram was constructed from relevant variables in the multivariable analysis. Discrimination and calibration of the nomogram were assessed. RESULTS: The cumulative incidence of SSI after 30 days was 0.49%. The median time from operation to SSI was 7 days (interquartile range, 4-10.5 days). SSI was classified as superficial incisional in 30 cases (93.8%), deep incisional in 1 case (3.1%), and organ/space in 1 case (3.1%). Staphylococcus aureus was the most common isolate. In multivariable analysis, duration of operation (P = .004) and American Society of Anesthesiologists' score (P = .031) were identified as independent risk factors for SSI. These variables formed the basis of a nomogram, which was validated internally by bootstrapping and reached a predictive accuracy of 70.1%. The calibration curve showed a good agreement between predicted probability and actual observation. CONCLUSION: The cumulative incidence of SSI in thyroid operation is <0.5%. American Society of Anesthesiologists' score and the duration of operation are independent risk factors for SSI. Antibiotic prophylaxis may be considered for selected patients based on the individual risk profile.

Agreement among healthcare professionals in ten European countries in diagnosing case-vignettes of surgical-site infections.

OBJECTIVE: Although surgical-site infection (SSI) rates are advocated as a major evaluation criterion, the reproducibility of SSI diagnosis is unknown. We assessed agreement in diagnosing SSI among specialists involved in SSI surveillance in Europe. METHODS: Twelve case-vignettes based on suspected SSI were submitted to 100 infection-control physicians (ICPs) and 86 surgeons in 10 European countries. Each participant scored eight randomly-assigned case-vignettes on a secure online relational database. The intra-class correlation coefficient (ICC) was used to assess agreement for SSI diagnosis on a 7-point Likert scale and the kappa coefficient to assess agreement for SSI depth on a three-point scale. RESULTS: Intra-specialty agreement for SSI diagnosis ranged across countries and specialties from 0.00 (95%CI, 0.00-0.35) to 0.65 (0.45-0.82). Inter-specialty agreement varied from 0.04 (0.00-0.62) in to 0.55 (0.37-0.74) in Germany. For all countries pooled, intra-specialty agreement was poor for surgeons (0.24, 0.14-0.42) and good for ICPs (0.41, 0.28-0.61). Reading SSI definitions improved agreement among ICPs (0.57) but not surgeons (0.09). Intra-specialty agreement for SSI depth ranged across countries and specialties from 0.05 (0.00-0.10) to 0.50 (0.45-0.55) and was not improved by reading SSI definition. CONCLUSION: Among ICPs and surgeons evaluating case-vignettes of suspected SSI, considerable disagreement occurred regarding the diagnosis, with variations across specialties and countries.

Laminar airflow ceiling size: no impact on infection rates following hip and knee prosthesis.

OBJECTIVE: Laminar airflow (LAF) systems are widely used, at least in orthopedic surgery. However, there is still controversial discussion about the influence of LAF on surgical site infection (SSI) rates. The size of the LAF ceiling is also often a question of debate. Our objective is to determine the effect of this technique under conditions of actual rather than ideal use. DESIGN: Cohort study using multivariate analysis with generalized estimating equations method. SETTING: Data for hip and knee prosthesis procedures from hospitals participating in the German national nosocomial infection surveillance system (KISS) from July 2004 to June 2009 were used for analysis. PATIENTS: A total of 33,463 elective hip prosthesis procedures due to arthrosis (HIP-A) from 48 hospitals, 7,749 urgent hip prosthesis procedures due to fracture (HIP-F) from 41 hospitals, and 20,554 knee prosthesis (KPRO) procedures from 38 hospitals were included. METHODS: The data were analyzed for hospitals with and without LAF in the operating rooms and by the size of the LAF ceiling. The endpoints were severe SSI rates. RESULTS: The overall severe SSI rate was 0.74 per 100 procedures for HIP-A, 2.39 for HIP-F, and 0.63 for KPRO. For all 3 prosthesis types, neither LAF nor the size of the LAF ceiling was associated with lower infection risk. CONCLUSIONS: The data demonstrate consistency and reproducibility with the results from earlier registry studies. Neither LAF nor ceiling size had an impact on severe SSI rates.