Screening asymptomatic households for Streptococcus pyogenes pharyngeal carriage as a part of in-hospital investigation of puerperal sepsis.

BACKGROUND: Invasive group A streptococcal (iGAS) infection in the peripartum setting is a rare but devastating disease occasionally occurring as a health care-associated infection (HAI). Current guidelines suggest enhanced surveillance and streptococcal isolate storage after a single case of iGAS, as well as a full epidemiological investigation that includes screening health care workers (HCWs) from several sites after 2 cases. Current guidelines do not recommend routine screening of household members of a patient with iGAS. METHODS: We conducted studies of 3 patients with iGAS puerperal sepsis and related epidemiologic and molecular investigations. RESULTS: Identical GAS emm gene types were found in pharyngeal cultures of 3 asymptomatic spouses of patients with iGAS puerperal sepsis. HCWs screened negative for GAS, and emm typing indicated that other iGAS cases from this hospital were sporadic and not related to the puerperal cases. CONCLUSIONS: The concurrent presence of the same emm type in a household member practically excludes the option of an inadvertent HAI or facility outbreak. Hence, we suggest that screening close family members for asymptomatic GAS carriage should be performed early as a part of infection prevention measures, as doing so would have significant utility in saving time and resources related to a full epidemiological inquiry.

A prospective survey of Pseudomonas aeruginosa colonization and infection in the intensive care unit.

BACKGROUND: Pseudomonas aeruginosa (PA) surveillance may improve empiric antimicrobial therapy, since colonizing strains frequently cause infections. This colonization may be 'endogenous' or 'exogenous', and the source determines infection control measures. We prospectively investigated the sources of PA, the clinical impact of PA colonization upon admission and the dynamics of colonization at different body sites throughout the intensive care unit stay. METHODS: Intensive care patients were screened on admission and weekly from the pharynx, endotracheal aspirate, rectum and urine. Molecular typing was performed using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain reaction (ERIC-PCR). RESULTS: Between November 2014 and January 2015, 34 patients were included. Thirteen (38%) were colonized on admission, and were at a higher risk for PA-related clinical infection (Hazard Ratio = 14.6, p = 0.0002). Strains were often patient-specific, site-specific and site-persistent. Sixteen out of 17 (94%) clinical isolates were identical to strains found concurrently or previously on screening cultures from the same patient, and none were unique. Ventilator associated pneumonia-related strains were identical to endotracheal aspirates and pharynx screening (87-75% of cases). No clinical case was found among patients with repeated negative screening. CONCLUSION: PA origin in this non-outbreak setting was mainly 'endogenous' and PA-strains were generally patient- and site-specific, especially in the gastrointestinal tract. While prediction of ventilator associated pneumonia-related PA-strain by screening was fair, the negative predictive value of screening was very high.