Kalisvar Marimuthu

MRSA Transmission Dynamics Among Interconnected Acute, Intermediate-Term, and Long-Term Healthcare Facilities in Singapore.

Background Methicillin-resistant Staphylococcus aureus (MRSA) is the most common healthcare-associated multidrug-resistant organism. Despite the interconnectedness between acute care hospitals (ACHs) and intermediate- and long-term care facilities (ILTCFs), the transmission dynamics of MRSA between healthcare settings is not well understood. Methods We conducted a cross-sectional study in a network comprising an ACH and 5 closely affiliated ILTCFs in Singapore. A total of 1700 inpatients were screened for MRSA over a 6-week period in 2014. MRSA isolates underwent whole-genome sequencing, with a pairwise single-nucleotide polymorphism (Hamming distance) cutoff of 60 core genome single-nucleotide polymorphisms used to define recent transmission clusters (clades) for the 3 major clones. Results MRSA prevalence was significantly higher in intermediate-term (29.9%) and long-term (20.4%) care facilities than in the ACH (11.8%) (P < .001). The predominant clones were sequence type [ST] 22 (n = 183; 47.8%), ST45 (n = 129; 33.7%), and ST239 (n = 26; 6.8%), with greater diversity of STs in ILTCFs relative to the ACH. A large proportion of the clades in ST22 (14 of 21 clades; 67%) and ST45 (7 of 13; 54%) included inpatients from the ACH and ILTCFs. The most frequent source of the interfacility transmissions was the ACH (n = 28 transmission events; 36.4%). Conclusions MRSA transmission dynamics between the ACH and ILTCFs were complex. The greater diversity of STs in ILTCFs suggests that the ecosystem in such settings might be more conducive for intrafacility transmission events. ST22 and ST45 have successfully established themselves in ILTCFs. The importance of interconnected infection prevention and control measures and strategies cannot be overemphasized.

Prevalence of Healthcare-Associated Infections and Antimicrobial Use Among Adult Inpatients in Singapore Acute-Care Hospitals: Results From the First National Point Prevalence Survey.

Background We conducted a national point prevalence survey (PPS) to determine the prevalence of healthcare-associated infections (HAIs) and antimicrobial use (AMU) in Singapore acute-care hospitals. Methods Trained personnel collected HAI, AMU, and baseline hospital- and patient-level data of adult inpatients from 13 private and public acute-care hospitals between July 2015 and February 2016, using the PPS methodology developed by the European Centre for Disease Prevention and Control. Factors independently associated with HAIs were determined using multivariable regression. Results Of the 5415 patients surveyed, there were 646 patients (11.9%; 95% confidence interval [CI], 11.1%-12.8%) with 727 distinct HAIs, of which 331 (45.5%) were culture positive. The most common HAIs were unspecified clinical sepsis (25.5%) and pneumonia (24.8%). Staphylococcus aureus (12.9%) and Pseudomonas aeruginosa (11.5%) were the most common pathogens implicated in HAIs. Carbapenem nonsusceptibility rates were highest in Acinetobacter species (71.9%) and P. aeruginosa (23.6%). Male sex, increasing age, surgery during current hospitalization, and presence of central venous or urinary catheters were independently associated with HAIs. A total of 2762 (51.0%; 95% CI, 49.7%-52.3%) patients were on 3611 systemic antimicrobial agents; 462 (12.8%) were prescribed for surgical prophylaxis and 2997 (83.0%) were prescribed for treatment. Amoxicillin/clavulanate was the most frequently prescribed (24.6%) antimicrobial agent. Conclusions This survey suggested a high prevalence of HAIs and AMU in Singapores acute-care hospitals. While further research is necessary to understand the causes and costs of HAIs and AMU in Singapore, repeated PPSs over the next decade will be useful to gauge progress at controlling HAIs and AMU.

Draft Genome Sequence of a Multidrug-Resistant New Delhi Metallo-β-Lactamase-1 (NDM-1)-Producing Escherichia coli Isolate Obtained in Singapore

ABSTRACT We report the draft genome sequence of a New Delhi metallo-β-lactamase-1 (NDM-1)-positive Escherichia coli isolate obtained from a surgical patient. The assembled data indicate the presence of 3 multidrug resistance plasmids, 1 of which shares 100% identity with an NDM-1 plasmid isolated previously from a nearby hospital, suggesting possible local transmission.

First report of emergence of OXA-48 carbapenemase-producing Enterobacteriaceae in Singapore: Proactive or reactive infection control strategy?

Carbapenemase-producing Enterobacteriaceae (CPE), especially Klebsiella pneumoniae have successfully spread worldwide.1 This epidemiologic success of CPE can be attributed, at least in part, to plasmid-mediated carbapenemase.2 The carbapenemhydrolysing b-lactamase OXA-48 was first identified in Turkey. Scattered cases and related outbreaks have been described in various countries since then.3 Here, we describe a nosocomial cluster of OXA-48 K pneumoniae, which lends support to a proactive rather than a reactive infection control policy for control of CPE. Since 2010, carbapenem-resistant Enterobacteriaceae (CRE) have regularly been clinically cultured at Tan Tock Seng Hospital (TTSH), a 1,500-bed teaching hospital in Singapore. When CRE is identified from clinical cultures, the patient is isolated in a single room with contact precaution comprising apron and gloves on entering the patient’s room and dedicated equipment for routine medical and nursing care (ie, stethoscope, sphygmomanometer, and thermometer). Index patient’s movement throughout the hospital is traced using an electronic Infection Control and Epidemiology Surveillance System (ICESS). Patients in the same ward as the index patient are pre-emptively placed on contact precaution and screened for CRE with 1 sample of rectal swab. Movements to and from the wards are restricted until screening has been completed except for discharges, transfers to intensive care units, and essential procedures. All patients identified as CPE carriers are tagged electronically and identified during subsequent admissions and outpatient clinic visits. A conventional multiplex polymerase chain reaction (PCR) incorporating specific primers targeting blaNDM, blaKPC, and blaOXA-48-like is routinely done on all clinical isolates of Enterobacteriaceae that are meropenem nonsusceptible. In July 2013, a 75-year-old female patient was admitted for an infected sacral ulcer. She had multiple comorbidities without any recent travel history. She was antibiotic experienced with multiple past hospitalizations at various institutions in Singapore. The admission blood cultures were negative. She underwent bone biopsy 5 days later and became febrile on the same day. Repeat blood cultures and bone biopsy cultures grew carbapenem-resistant Citrobacter koseri. This isolate was found to harbor blaOXA-48. Fifty

An Outbreak of Streptococcus pyogenes in a Mental Health Facility: Advantage of Well-Timed Whole-Genome Sequencing Over emm Typing

OBJECTIVEWe report the utility of whole-genome sequencing (WGS) conducted in a clinically relevant time frame (ie, sufficient for guiding management decision), in managing a Streptococcus pyogenes outbreak, and present a comparison of its performance with emm typing.SETTINGA 2,000-bed tertiary-care psychiatric hospital.METHODSActive surveillance was conducted to identify new cases of S. pyogenes. WGS guided targeted epidemiological investigations, and infection control measures were implemented. Single-nucleotide polymorphism (SNP)-based genome phylogeny, emm typing, and multilocus sequence typing (MLST) were performed. We compared the ability of WGS and emm typing to correctly identify person-to-person transmission and to guide the management of the outbreak.RESULTSThe study included 204 patients and 152 staff. We identified 35 patients and 2 staff members with S. pyogenes. WGS revealed polyclonal S. pyogenes infections with 3 genetically distinct phylogenetic clusters (C1-C3). Cluster C1 isolates were all emm type 4, sequence type 915 and had pairwise SNP differences of 0-5, which suggested recent person-to-person transmissions. Epidemiological investigation revealed that cluster C1 was mediated by dermal colonization and transmission of S. pyogenes in a male residential ward. Clusters C2 and C3 were genomically diverse, with pairwise SNP differences of 21-45 and 26-58, and emm 11 and mostly emm120, respectively. Clusters C2 and C3, which may have been considered person-to-person transmissions by emm typing, were shown by WGS to be unlikely by integrating pairwise SNP differences with epidemiology.CONCLUSIONSWGS had higher resolution than emm typing in identifying clusters with recent and ongoing person-to-person transmissions, which allowed implementation of targeted intervention to control the outbreak.Infect Control Hosp Epidemiol 2018;852-860.

Environmental colonization and onward clonal transmission of carbapenem-resistant Acinetobacter baumannii (CRAB) in a medical intensive care unit: the case for environmental hygiene

BackgroundIn May 2015, we noticed an increase in carbapenem-resistant Acinetobacter baumannii (CRAB) infections in the Medical Intensive Care Unit (MICU). To investigate this, we studied the extent of environmental contamination and subsequent onward clonal transmission of CRAB.MethodsWe conducted a one-day point prevalence screening (PPS) of the patients and environment in the MICU. We screened patients using endotracheal tube aspirates and swabs from nares, axillae, groin, rectum, wounds, and exit sites of drains. We collected environmental samples from patients’ rooms and environment outside the patients’ rooms. CRAB isolates from the PPS and clinical samples over the subsequent one month were studied for genetic relatedness by whole genome sequencing (WGS).ResultsWe collected 34 samples from seven patients and 244 samples from the environment. On the day of PPS, we identified 8 CRAB carriers: 3 who screened positive and 5 previously known clinical infections. We detected environmental contamination in nearly two-thirds of the rooms housing patients with CRAB. WGS demonstrated genetic clustering of isolates within rooms but not across rooms. We analysed 4 CRAB isolates from clinical samples following the PPS. One genetically-related CRAB was identified in the respiratory sample of a patient with nosocomial pneumonia, who was admitted to the MICU five days after the PPS.ConclusionThe extensive environmental colonization of CRAB by patients highlights the importance of environmental hygiene. The transmission dynamics of CRAB needs further investigation.

331Risk Factors for Vancomycin-resistant Enterococci and Carbapenemase-producing Carbapenem-resistant Enterobacteriaceae Colonization at admission to a Tertiary-care Center

331. Risk Factors for Vancomycin-resistant Enterococci and Carbapenemase-producing Carbapenem-resistant Enterobacteriaceae Colonization at admission to a Tertiary-care Center Angela Chow, MBBS, MPH, MS; Kalisvar Marimuthu, MBBS, MRCP; Bee Fong Poh, RN; Nwe-Ni Win, MBBS; Jia Qi Kum, BSc; Brenda Ang, MBBS, M Med, MPH, FAMS; Institute of Infectious Disease and Epidemiology, Tan Tock Seng Hospital, Singapore, Singapore; Infection Control, Tan Tock Seng Hospital, Singapore, Singapore; Clinical Epidemiology, Tan Tock Seng Hospital, Singapore, Singapore

Improved outcomes from HIV/TB co-infection in Singapore following a switch to earlier anti-retroviral therapy.

Recent clinical trials have provided clear evidence to support early anti‐retroviral therapy (ART) in patients with HIV/TB co‐infection and low CD4 counts. We investigated how this has changed treatment and outcomes in Singapore.