The emergence of carbapenem resistance in Klebsiella pneumoniae represents a major global public health concern. Nosocomial outbreaks caused by multidrug-resistant K. pneumoniae are commonly reported to result in high morbidity and mortality due to limited treatment options. Between October 2019 and January 2020, two concurrent high-mortality nosocomial outbreaks occurred in a referral hospital in Ho Chi Minh City, Vietnam. We performed genome sequencing and phylogenetic analysis of eight K. pneumoniae isolates from infected patients and two environmental isolates for outbreak investigation. We identified two outbreaks caused by two distinct lineages of the international sequence type (ST) 16 clone, which displayed extensive drug resistance, including resistance to carbapenem and colistin. Carbapenem-resistant ST16 outbreak strains clustered tightly with previously described ST16 K. pneumoniae from other hospitals in Vietnam, suggesting local persistence and transmission of this particular clone in this setting. We found environmental isolates from a hospital bed and blood pressure cuff that were genetically linked to an outbreak case cluster, confirming the potential of high-touch surfaces as sources for nosocomial spread of K. pneumoniae . Further, we found colistin resistance caused by disruption of the mgrB gene by an ISL3-like element, and carbapenem resistance mediated by a transferable IncF/bla OXA-181 plasmid carrying the ISL3-like element. Our study highlights the importance of coordinated efforts between clinical and molecular microbiologists and infection control teams to rapidly identify, investigate and contain nosocomial outbreaks. Routine surveillance with advanced sequencing technology should be implemented to strengthen hospital infection control and prevention measures.

Typhoid fever remains a significant cause of morbidity and mortality in Asia and Africa. The emergence of azithromycin resistance in South Asia is concerning, as azithromycin is one of the last effective oral drugs for treating typhoid. In mid-2019, three azithromycin-resistant (AzithR) S. Typhi isolates were isolated from typhoid fever patients attending Patan Hospital, Kathmandu, Nepal. These organisms were whole genome sequenced and compared with a global collection. We found that the three AzithR isolates belonged to the H58 lineage and were genetically identical; they were distantly related to contemporaneous S. Typhi from Nepal and AzithR S. Typhi recently described in Bangladesh. Azithromycin resistance was mediated by nonsynonymous mutation in the acrB gene (R717L). Clinical information from one patient suggested non-response to azithromycin treatment. Further investigations are needed to evaluate treatment responses to azithromycin, predict the evolutionary trajectories of AzithR S. Typhi, and track the transmission of these organisms.

Quality of service (QoS) differentiation is an integral component of any networking system, particularly, with the current and future great diversity of users' applications and their manifold requirements. In optical burst switching (OBS) networks, there are two approaches for QoS differentiation: one is based on offset time and the other is based on burst length. This paper presents a mechanism of QoS differentiation based on both offset time and burst length, in which the offset times are calculated to achieve a complete isolation of data loss between priority classes and the burst length is adaptively adjusted according to the feedbacked void size. The simulation results show that the mechanism of QoS differentiation based on offset time and adjusted burst length not only increases the successful scheduling rate but also reduces the burst delay.

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