Stewardship / Resistance Scan for Aug 16, 2018

MRSA colonization
;
Mupirocin-resistant S aureus in Africa

VA study finds MRSA colonization significantly increases infection risk

A longitudinal study of inpatients at Department of Veterans Affairs (VA) acute care hospitals has found that methicillin-resistant Staphylococcus aureus (MRSA) colonization significantly increases the risk of MRSA infection, with a substantial number of infections occurring after discharge from the hospital, VA researchers report in Clinical Infectious Diseases.

The retrospective study looked at a cohort of 985,626 inpatient admissions to VA acute care hospitals from 2008 through 2015, focusing only on patients who had surveillance testing for colonization status performed on admission. A patient whose admission MRSA screen and all subsequent screens were negative was categorized as not colonized. A patient who had a positive MRSA screen was classified as an importer, and a patient who had a negative MRSA screen on admission, but a subsequent positive screen, was defined as an acquirer.

For each of the three groups, the researchers calculated the proportion of MRSA infections that occurred prior to discharge and at 30, 90, 180, and 365 days after discharge, then determined the relationship between MRSA colonization status and infection.

Overall, 903,190 patients (91.6%) were found not to be colonized with MRSA during their hospitalization, 72,388 (7.3%) were importers, and 10,048 (1.0%) were acquirers. The MRSA infection rate across the predischarge and 180-day postdischarge time period was 5.5% in importers and 7.0% in acquirers, rising to 11.4% in importers and 11.7% in acquirers who were admitted directly to the intensive care unit. In the multivariable regression analysis, the predischarge hazard ratio for MRSA infection was 29.6 for importers and 28.8 for acquirers compared to those not colonized. When measured at 180 days postdischarge, 63.9% of all pre- and postdischarge infections among importers occurred during the postdischarge period. For acquirers, this value was 61.2%.

"In conclusion, acquisition of MRSA during hospitalization markedly increases the risk to a patient of subsequent infection that may not become manifest until after discharge," the authors wrote. "These factors should be taken into account when optimizing infection control strategies for MRSA."
Aug 11 Clin Infect Dis study

 

Study indicates high prevalence of mupirocin-resistant S aureus in Africa

A systematic review and meta-analysis yesterday in Antimicrobial Resistance & Infection Control suggests there is a high rate mupirocin-resistant S aureus in Africa.

Mupirocin nasal ointment, alone or in combination with chlorhexidine, is considered the main decolonization strategy for S aureus carriage, which is an important risk factor for subsequent infection among patients with surgical site infections and atopic dermatitis. The emergence of mupirocin-resistant (mupR) S aureus threatens this decolonization strategy. While mupR S aureus has been reported in several countries, there is no data summarizing screening, prevalence, characterization, and geographic spread in Africa.

Using five electronic databases, researchers from South Africa and Nigeria identified 43 eligible studies. Only 12 of 54 African countries (22%) reported data on screening for mupR S aureus. The pooled prevalence of mupR S aureus in Africa, based on 11 human studies conducted in South Africa, Ghana, Libya, Egypt, and Nigeria, was 14%. The proportion of S aureus isolates with the mupA gene, which confers high-level mupirocin resistance (HmupR), ranged between 0.5 and 8%. Isolates that expressed HmupR and low-level resistance (LmupR) ranged between 0.5 and 38% and 4 and 47%, respectively. The frequency of mupR-MRSA isolates ranged between 5 and 50%.

The authors of the study say the findings show the paucity of data on the continent and support the need for mupR S aureus surveillance data to provide information on it epidemiology and clinical significance. In addition, they note the need for data on administration and use of mupirocin in the community and hospital setting in Africa.  
Aug 15 Antimicrob Resist Infect Control study

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