The outbreak of multispecies carbapenemase-producing Enterobacterales associated with pediatric ward sinks: IncM1 plasmids act as vehicles for cross-species transmission.

BACKGROUND: This study describes an outbreak caused by multispecies carbapenemase-producing Enterobacterales (CPE) occurring in a pediatric ward at an academic medical center in Tokyo. METHODS: The index case involved a 1-year-old boy with Klebsiella variicola (CPE) detected in anal swabs in June 2016. The second case was Klebsiella quasipneumoniae (CPE) occurred in March 2017 followed by further spread, leading to the declaration of an outbreak in April 2017. Extensive environmental and patient microbiological sampling was performed. The relatedness of the isolates was determined using draft-whole-genome sequencing. RESULTS: CPE surveillance cultures of patients and environments were positive in 19 patients and 9 sinks in the ward. The sinks in hospital rooms uninhabited by CPE patients exhibited no positive CPE-positive specimen during the outbreak. All CPE strains analyzed using draft-whole-genome sequencing harbored blaIMP-1, except for one harboring blaIMP-11; these strains harbored identical blaIMP-1-carrying IncM1 plasmids. CPE was detected even after sink replacement; infection-control measures focused on sinks were implemented and the CPE outbreak ended after 7 months. CONCLUSIONS: Multiple bacterial species can become CPE via blaIMP-1-carrying IncM1 plasmids of the same origin and spread through sinks in a hospital ward. Thorough infection-control measures implemented as a bundle might be crucial.

Spread of CTX-M-15 extended-spectrum ß-lactamase-producing Escherichia coli isolates through household contact and plasmid transfer.

We document the household spread of extended-spectrum ß-lactamase-producing Escherichia coli. One isolate belonged to sequence type 1193 and caused urinary tract infection in a 4-month-old female, and the other isolate belonged to sequence type 131 and colonized three family members, including the index patient. These isolates carried similar Inc-I1-Iγ plasmids, harboring blaCTX-M-15.

Diagnostic usefulness of ribosomal protein l7/l12 for pneumococcal pneumonia in a mouse model.

The capsular antigen detection (CAD) kit is widely used in clinics to detect Streptococcus pneumoniae infection from urine, because it is rapid, convenient, and effective. However, there are several disadvantages, including false-positive results in children colonized with S. pneumoniae and prolonged positive readings even after the bacteria have been cleared. RP-L7/L12 is a component of the 50S ribosome that is abundant in all bacteria and is specific for each bacterial species. We investigated whether RP-L7/L12 could be used to accurately diagnose pneumococcal pneumonia infection in mouse models of pneumonia and colonization generated by infecting CBA/JN or CBA/N mice, respectively, with S. pneumoniae strain 741. RP-L7/L12 detection by enzyme-linked immunosorbent assay accurately assessed active lung infection, as RP-L7/L12 levels decreased simultaneously with the bacterial lung burden after imipenem administration in the pneumonia mouse model. Based on the data, antibodies detecting RP-L7/L12 were applied to rapid immunochromatographic strips (ICS) for urine sample testing. When we compared the ICS test with the CAD kit in the pneumonia model, the results correlated well. Interestingly, however, when the lung bacterial burden became undetectable after antibiotic treatment, the ICS test was correspondingly negative, even though the same samples tested by the CAD kit remained positive. Similarly, while the ICS test exhibited negative results in the nasal colonization model, the CAD kit demonstrated positive results. Bacterial RP-L7/L12 may be a promising target for the development of new methods to diagnose infectious disease. Further studies are warranted to determine whether such a test could be useful in children.