A Risk Prediction Model and Risk Score of SARS-CoV-2 Infection Following Healthcare-Related Exposure.

Hospital workers are at high risk of contact with COVID-19 patients. Currently, there is no evidence-based, comprehensive risk assessment tool for healthcare-related exposure; so, we aimed to identify independent factors related to COVID-19 infection in hospital workers following workplace exposure(s) and construct a risk prediction model. We analyzed the COVID-19 contact tracing dataset from 15 July to 31 December 2021 using multiple logistic regression analysis, considering exposure details, demographics, and vaccination history. Of 7146 included exposures to confirmed COVID-19 patients, 229 (4.2%) had subsequently tested positive via RT-PCR. Independent risk factors for a positive test were having symptoms (adjusted odds ratio 4.94, 95%CI 3.83−6.39), participating in an unprotected aerosol-generating procedure (aOR 2.87, 1.66−4.96), duration of exposure >15 min (aOR 2.52, 1.82−3.49), personnel who did not wear a mask (aOR 2.49, 1.75−3.54), exposure to aerodigestive secretion (aOR 1.5, 1.03−2.17), index patient not wearing a mask (aOR 1.44, 1.01−2.07), and exposure distance <1 m without eye protection (aOR 1.39, 1.02−1.89). High-potency vaccines and high levels of education protected against infection. A risk model and scoring system with good discrimination power were built. Having symptoms, unprotected exposure, lower education level, and receiving low potency vaccines increased the risk of laboratory-confirmed COVID-19 following healthcare-related exposure events.

T cell mediated immunity against influenza H5N1 nucleoprotein, matrix and hemagglutinin derived epitopes in H5N1 survivors and non-H5N1 subjects.

BACKGROUND: Protection against the influenza virus by a specific antibody is relatively strain specific; meanwhile broader immunity may be conferred by cell-mediated immune response to the conserved epitopes across influenza virus subtypes. A universal broad-spectrum influenza vaccine which confronts not only seasonal influenza virus, but also avian influenza H5N1 virus is promising. METHODS: This study determined the specific and cross-reactive T cell responses against the highly pathogenic avian influenza A (H5N1) virus in four survivors and 33 non-H5N1 subjects including 10 H3N2 patients and 23 healthy individuals. Ex vivo IFN-γ ELISpot assay using overlapping peptides spanning the entire nucleoprotein (NP), matrix (M) and hemagglutinin (HA) derived from A/Thailand/1(KAN-1)/2004 (H5N1) virus was employed in adjunct with flow cytometry for determining T cell functions. Microneutralization (microNT) assay was performed to determine the status of previous H5N1 virus infection. RESULTS: IFN-γ ELISpot assay demonstrated that survivors nos. 1 and 2 had markedly higher T cell responses against H5N1 NP, M and HA epitopes than survivors nos. 3 and 4; and the magnitude of T cell responses against NP were higher than that of M and HA. Durability of the immunoreactivity persisted for as long as four years after disease onset. Upon stimulation by NP in IFN-γ ELISpot assay, 60% of H3N2 patients and 39% of healthy subjects exhibited a cross-reactive T cell response. The higher frequency and magnitude of responses in H3N2 patients may be due to blood collection at the convalescent phase of the patients. In H5N1 survivors, the effector peptide-specific T cells generated from bulk culture PBMCs by in vitro stimulation displayed a polyfunction by simultaneously producing IFN-γ and TNF-α, together with upregulation of CD107a in recognition of the target cells pulsed with peptide or infected with rVac-NP virus as investigated by flow cytometry. CONCLUSIONS: This study provides an insight into the better understanding on the homosubtypic and heterosubtypic T cell-mediated immune responses in H5N1 survivors and non-H5N1 subjects. NP is an immunodominant target of cross-recognition owing to its high conservancy. Therefore, the development of vaccine targeting the conserved NP may be a novel strategy for influenza vaccine design.

Epidemiology, clinical characteristics, and treatment outcomes of patients with COVID-19 at Thailand's university-based referral hospital.

BACKGROUND: The epidemiology and outcomes of COVID-19 patients in Thailand are scarce. METHODS: This retrospective cohort study included adult hospitalized patients who were diagnosed with COVID-19 at Siriraj Hospital during February 2020 to April 2020. RESULTS: The prevalence of COVID-19 was 7.5% (107 COVID-19 patients) among 1409 patients who underwent RT-PCR for SARS-CoV-2 detection at our hospital during the outbreak period. Patients with COVID-19 presented with symptoms in 94.4%. Among the 104 patients who were treated with antiviral medications, 78 (75%) received 2-drug regimen (lopinavir/ritonavir or darunavir/ritonavir plus chloroquine or hydroxychloroquine), and 26 (25%) received a 3-drug regimen with favipiravir added to the 2-drug regimen. Disease progression was observed in 18 patients (16.8%). All patients with COVID-19 were discharged alive. CONCLUSIONS: The prevalence of COVID-19 was 7.5% among patients who underwent RT-PCR testing, and 10% among those having risk factors for COVID-19 acquisition. Combination antiviral therapies for COVID-19 patients were well-tolerated and produced a favorable outcome.

First characterization of Tn1546-like structures of vancomycin-resistant Enterococcus faecium Thai isolates.

INTRODUCTION: Vancomycin-resistant Enterococcus faecium (VREfm) carrying vanA was first isolated from patient at Siriraj Hospital, Thailand in 2004. Since then, VREfm isolates have been detected increasingly in this 2500-bed university hospital. To understand the epidemiology of vanA VREfm in this setting, the isolates collected during 2004-2013 were characterized. METHODS: A total of 49 vanA VREfm isolates previously confirmed by multiplex PCR were characterized by determining resistance phenotypes to vancomycin, teicoplanin, ampicillin and ciprofloxacin by broth microdilution method. Multilocus sequence typing (MLST) and virulence genes of those isolates were investigated. The Tn1546 structure diversity was studied by long-range overlapping PCR and primer walking sequencing. RESULTS: Of all isolates studied, 9 sequence types (ST17, ST80, ST78, ST730, ST203, ST18, ST280, ST64, ST323) in clonal complex 17 and a novel ST1051 were revealed. The esp-positive isolates were 73.5%. Of all vanA operons characterized, at least 9 types of Tn1546-like structures were detected. All of vanA determinants contained 5'-end different from the Tn1546 prototype. Approximately 47% of them also carried the insertion sequence IS1251 at the intergenic region between vanS and vanH. Interestingly, another IS (ISEfa4) was found to be inside the sequence of IS1251 in ST17 isolate. CONCLUSION: Heterogeneity of vanA VREfm was observed. Nearly all of isolates studied belonged to CC17. One novel ST1051 strain was detected. Isolates in the initial period carried vanA operon similar to the prototype. The diversity of vanA determinants has been increased in the recent isolates. A novel vanA operon structure was detected.

Homosubtypic and heterosubtypic antibodies against highly pathogenic avian influenza H5N1 recombinant proteins in H5N1 survivors and non-H5N1 subjects.

Six recombinant vaccinia viruses containing HA, NA, NP, M or NS gene insert derived from a highly pathogenic avian influenza H5N1 virus, and the recombinant vaccinia virus harboring plasmid backbone as the virus control were constructed. The recombinant proteins were characterized for their expression and subcellular locations in TK(-) cells. Antibodies to the five recombinant proteins were detected in all 13 sequential serum samples collected from four H5N1 survivors during four years of follow-up; and those directed to rVac-H5 HA and rVac-NA proteins were found in higher titers than those directed to the internal proteins as revealed by indirect immunofluorescence assay. Although all 28 non-H5N1 subjects had no neutralizing antibodies against H5N1 virus, they did have cross-reactive antibodies to those five recombinant proteins. A significant increase in cross-reactive antibody titer to rVac-H5 HA and rVac-NA was found in paired blood samples from patients infected with the 2009 pandemic virus.

Prevalence and molecular characterization of human metapneumovirus in influenza a negative sample in Thailand.

BACKGROUND: Human metapneumovirus (hMPV) causes respiratory tract infection in influenza-like illness. The role of hMPV infections in all age groups in Thailand has not yet been investigated. Thus, the objective of this study was to determine prevalence of hMPV infection in all age groups in Thailand during 2011. METHODS: A total of 1,184 nasopharyngeal washes were collected from hospitalized patients and sent to the Department of Microbiology, Siriraj Hospital, for influenza A virus detection. Real-time polymerase chain reaction (PCR) was used to detect hMPV infection. Partially, F gene from hMPV positive samples were sequenced and used for genotyping by phylogenetic tree analysis. RESULTS: The prevalence of hMPV for all age groups was 6.3%. The highest prevalence of hMPV infection was in children aged <2 years. Of 71 hMPV-positive patients, three (4.2%) were coinfected with respiratory syncytial virus (RSV), two with rhinovirus (2.8%), one with coronavirus (1.4%), and one with RSV and adenovirus (1.4%). Phylogenetic analysis of F gene revealed that 96.8% of hMPV detected was subgenotype B1, 1.6% was sublineage A2a, and 1.6% was A2b. Genetic variation of F gene was much conserved. CONCLUSION: We demonstrated the prevalence of hMPV subgenotype B1 circulating in Thailand during 2011.

Epidemiology of urinary tract infection among spinal cord injured patients in rehabilitation ward at Siriraj Hospital.

BACKGROUND AND OBJECTIVE: A prophylactic antibiotic in retrograde investigations (Ix) such as an urodynamic study was suggested by the European Association of Urology in order to prevent urinary tract infection (UTI) in the neurogenic bladder However finding an appropriate antibiotic is questionable since bacterial types and their sensitivities are variable in different settings. Therefore, the present study was aimed to find out the epidemiology of UTI in spinal cord injured (SCI) patients within the rehabilitation ward at Siriraj Hospital. MATERIAL AND METHOD: A retrospective chart review of 100 SCI patients admitted to the rehabilitation ward between 2006 and 2010 was done. Symptomatic UTI events, urine cultures, and sensitivities (C/S) were reviewed Demographic data and possible UTI-associated factors were collected and examined the association with the occurrence of UTI RESULTS: There were 64 males and 36 females with a mean age of 42.9 (SD 15.8) years. Most of them (77%) were injured at cervical and thoracic spinal cords. Forty-five patients had 57 UTI episodes. Escherichia coli was the most common isolated pathogen (50%), followed by Pseudomonas aeruginosa (17.3%), and Enterococcus faecalis (7.7%). The top three most sensitive antibiotics were imipenem, amikacin, and piperacillin/tazobactam. Unfortunately, gentamicin, ceftriaxone, and ciprofloxacin, which were frequently used as a prophylactic antibiotic, had the efficacy for only 51.9%, 38.5%, and 28.8% ofpathogens respectively. The mean length ofstay ofpatients with UTI was far greater than non-UTI patients, 45.5 (SD 24.4) versus 30.4 (SD 14.8) days (p = 0.001). Vesicoureteric reflux (VUR) (OR 21.2, 95% CI2.1 to 214.2) and increased intravesical pressure at storage phase (OR 1.1, 95% CI 1.004-1.113) were significant riSk factors for post investigation UTI. CONCLUSION: UTI was commonly observed in SCI patients within the rehabilitation ward The most common uropathogen was Escherichia coli. Therefore, a prophylactic antibiotic such as amikacin should be prescribed in patients with VUR and increased intravesical pressure at storage phase.

Candidemia in Siriraj Hospital: epidemiology and factors associated with mortality.

OBJECTIVE: To study the epidemiology of candidemia and to identify risk factors for mortality among adult patients MATERIAL AND METHOD: Retrospective analysis of patients with candidemia in a 2400-bed tertiary-care university hospital in Bangkok, Thailand from June 2006 to May 2009. RESULTS: During the study period, 147 patients (50% male) with clinically significant candidemia were identified, with a mean age of 61 years. The underlying conditions included renal failure (47%), abdominal surgery within 30 days (31%), diabetes (27%), hematologic malignancies (25%), solid malignancies (25%), neutropenia (23%), and liver disease (11%). Nearly all patients (98%) received antibacterial therapy within 30 days. The four most common Candida species were C. albicans (39%), C. tropicalis (28%), C. glabrata (22%) and C. parapsilosis (6%). Only sixty-nine patients (47%) received appropriate antifungal therapy within 72 hours. The 28-day all-cause mortality was 59%. By multivariate analysis, the independent risk factors associated with mortality were neutropenia from chemotherapy OR = 9.12 (2.94-28.31), septic shock OR = 3.66 (1.54-8.66), ICU admission OR = 3.18 (1.27-7.92), inappropriate antifungal therapy within 72 hours OR = 2.38 (1.07-5.28) and renal failure OR = 2.34 (1.07-5.13). CONCLUSION: Adult patients with candidemia had a high mortality rate particularly those receiving an inappropriate antifungal therapy. Empirical antifungal therapy should be considered in selected patients on the basis of underlying conditions, severity of illness and risk factors for mortality.

Biological properties of H5 hemagglutinin expressed by vaccinia virus vector and its immunological reactivity with human sera.

A recombinant vaccinia virus harboring the full length hemagglutinin (HA) gene derived from a highly pathogenic avian influenza A/Thailand/1(KAN-1)/2004 (H5N1) virus (rVac-H5 HA virus) was constructed. The immunogenicity of the expressed HA protein was characterized using goat antiserum, mouse monoclonal antibody, and human sera. The expressed HA protein localized both in the cytoplasm and on the cytoplasmic membrane of the thymidine kinase negative cells infected with the rVac-H5 HA virus, as determined by immunofluorescence assay. Western blot analysis demonstrated that the rVac-H5 HA protein was post-translationally processed by proteolytic cleavage of the HA0 precursor into HA1 and HA2 domains; and all of these HA forms were immunogenic in BALB/c mice. The molecular weight (MW) of each HA domain was the same as the wild-type H5 HA produced in Madin-Darby canine kidney cells infected with the H5N1 virus, but was higher than that expressed by a baculovirus-insect cell system. Sera from all H5N1 survivors reacted to HA0, HA1, and HA2 domains; whereas sera from H5N1-uninfected subjects reacted to the HA2 domain only, but not to HA0 or HA1, indicating that some cross-subtypic immunity exists in the general population. There was a lot-to-lot variation of the recombinant HA produced in the baculovirus-insect cell system that might affect the detection rate of antibody directed against certain HA domains.

Seroprevalence of 2009 H1N1 virus infection and self-reported infection control practices among healthcare professionals following the first outbreak in Bangkok, Thailand.

A serologic study with simultaneous self-administered questionnaire regarding infection control (IC) practices and other risks of influenza A (H1N1) pdm09 (2009 H1N1) infection was performed approximately 1 month after the first outbreak among frontline healthcare professionals (HCPs). Of 256 HCPs, 33 (13%) were infected. Self-reported adherence to IC practices in >90% of exposure events was 82·1%, 73·8%, and 53·5% for use of hand hygiene, masks, and gloves, respectively. Visiting crowded public places during the outbreak was associated with acquiring infection (OR 3·1, P = 0·019). Amongst nurses, exposure to HCPs with influenza-like illness during the outbreak without wearing a mask was the only identified risk factor for infection (OR = 2·3, P = 0·039).

Nasal carriage of inducible dormant and community-associated methicillin-resistant Staphylococcus aureus in an ambulatory population of predominantly university students.

BACKGROUND: We studied risk factors for nasal colonization with inducible dormant methicillin-resistant Staphylococcus aureus (ID-MRSA) and community-associated MRSA (CA-MRSA) in a cohort of predominantly university students. METHODS: Nasal surveillance cultures were performed in student health and ambulatory clinics. Molecular features were identified and risk factors for CA-MRSA and ID-MRSA colonization were determined by logistic regression. RESULTS: Of the 1000 participants, 89% (n = 890) were university students. Sixty-four percent were female, 59% Caucasian. The mean age was 23.5 years; 1.6% (n = 16) were CA-MRSA and 1.4% (n = 14) were ID-MRSA colonized. Fifteen (94%) of the CA-MRSA strains were PFGE type IV. pvl (Panton-Valentine leukocidin gene) positivity was 75% in CA-MRSA and 57% in ID-MRSA. ID-MRSA isolates were pulsed-field gel electrophoresis (PFGE) type I, 7%; type II, 14%; type V, 7%; and type IV, 71%. CA-MRSA SCCmec classification was 94% type IV and 6% type V. Risk factors for carriage of CA-MRSA were older age (OR 1.046, p=0.040) and dog ownership (OR 1.450, p=0.019). Single family home (OR 0.040, p=0.007) was a protective factor. There were no significant variables of association found for ID-MRSA colonization. CONCLUSIONS: ID-MRSA/CA-MRSA colonization was low. Most isolates were PFGE types IV and II, pvl-positive and susceptible to several antibiotics. Older age and dog ownership were risk factors for CA-MRSA. Future studies are needed to assess the impact of ID-MRSA carriage.

Impact of 2 different levels of performance feedback on compliance with infection control process measures in 2 intensive care units.

BACKGROUND: Performance monitoring and feedback of infection control process measures is an important tool for improving guideline adherence. Different feedback strategies may lead to distinctive outcomes. OBJECTIVES: Our objective was to determine the relative impact of 2 different levels of feedback on compliance in an intensive care unit (ICU) setting. METHODS: Proportion of head of bed (HOB) elevation, hand hygiene (HH) compliance, and proportion of femoral catheter (FC) to all central venous catheter-days were observed in a medical ICU and a surgical ICU. After a 3-month baseline observation phase (phase 1; P1), we provided quarterly feedback on these process measures and major health care-associated infections (HAIs) to unit leaders from July 2004 to June 2005 (P2). From July 2005 to June 2006 (P3), feedback parameters were also provided to unit leaders and to all staff via 48 x 72-inch color posters in ICU personnel-only areas. At the end of the study, a survey was performed to assess the influence of the posters and HH observations. RESULTS: The analysis of IC process measures included 6948 HOB elevation observations, 1576 HH opportunities, and 16,591 catheter-days. In P2, the overall compliance with HOB elevation and the proportion of FC use significantly improved from 51% to 88% (P < .001) and 13% to 7% (P < .001), respectively. No significant difference in HH compliance was observed during this phase (40% vs 47%, respectively; P = .28). Comparing P3 with P2, HH compliance significantly improved from 47% to 71% (P < .001), and there was a slight improvement in HOB elevation rate from 88% to 93% (P < .001). There was no significant change in FC use in P3. There were 53 survey respondents. Sixty percent reported that the poster information changed their practices. Nearly all respondents (92%) knew that their HH behavior was being observed; however, 61% claimed that HH compliance was not influenced by observation. CONCLUSION: Feedback of infection control process measures and major HAIs to unit leadership significantly improved compliance with HOB elevation rate and FC use but not HH. Multilevel feedback significantly improved HH compliance and delivered a satisfactory level of compliance with HOB and FC use in both ICUs during the study period.

Effect of an education program on the prevention of ventilator-associated pneumonia: A multicenter study.

OBJECTIVE: To evaluate the effect of an educational program targeted on modifiable risk factors on ventilator-associated pneumonia (VAP) rates. MATERIAL AND METHOD: After a preliminary study on VAP risk factors was conducted at one teaching hospital, a pre- and post-interventional study was then performed on 12 hospitals in Thailand from January 1, 2002 to June 30, 2003. Each hospital randomly selected 20 patients, who were on mechanical ventilation to be enrolled The study was divided into two phases; 1) pre-intervention, 2) post-intervention. Data collected included patients 'demography and risk factors for VAP During pre-interventional phase, data on risk factors for VAP was analyzed and fedback to healthcare providers in the wards by an infection control nurse (ICN) of the individual hospital. An educational programme on the prevention of VAP was introduced by the ICN. Ventilator-associated pneumonia rates and their risk factors were continuously monitored during the post-interventionl phase. RESULTS: Two hundred and forty four patients in the pre-interventional phase and 254 patients in the post-interventional phase were included. There was no significant difference in the demography between these two patient populations. After the intervetion, there was a significant improvement in hand-hygiene practices (p<0.001) among healthcare providers and increased use of sucralfate (p=0.05) for stress ulcer prophylaxis. Ventilation-associated pneumonia rate (40.5% vs. 24%; p<0.001) and crude mortality rate associated with VAP (12.3% vs. 8.7%; p<0.001) were also reduced CONCLUSION: The educational programme targeted on modifiable risk factors for prevention of VAP was effective and should be considered as an intervention to reduce VAP rates in developing countries.

Development of national guidelines for the prevention and control of nosocomial infections.

OBJECTIVE: To develop a national evidence-based guidelines for the prevention and control of nosocomial infection. MATERIAL AND METHOD: Draft guidelines for the prevention and control of nosocomial infection were developed by the researchers and reviewed by a 10 member panel of experts. The guidelines were modified by brainstorming of 55 practitioners in July 2002. The guidelines were tested for their applicability in 20 hospitals across the country in 2002. The participants gave suggestions on the guidelines which were modified accordingly. The guidelines were finalized by brainstorming of the 55 practitioners in August 2003. RESULTS: National guidelines for the prevention and control of nosocomial infections were developed. Twenty-one topics were included. Modifications of the drafted guidelines were made four times according to the opinions of 10 experts, twice by brainstorming of 55 practitioners and by the suggestions of participants from 20 hospitals where they were tested. The practices in hospitals with different facilities were also suggested in the guidelines. CONCLUSION: National guidelines for prevention and control of nosocomial infection were formulated. Their application for use in every hospital and periodic reviews are expected.

Microbial and heavy metal contamination of treated hospital wastewater in Thailand.

OBJECTIVES: To determine the microbial and heavy metal contamination of treated hospital wastewater MATERIAL AND METHOD: Methods of treating wastewater were acquired by questionnaires. Chlorine concentration, pH, bacteria and parasites in treated wastewater were tested in the individual hospitals. Heavy metal concentrations were measured by atomic absorption spectrophotometry. RESULTS: In 2002, 72 hospitals were included in the present study. The common methods of treating wastewater were activated sludge and oxidation ditch. Bacteria exceeded standard numbers, pathogenic bacteria and parasites were found in two-thirds of the hospitals. Heavy metals, namely lead, chromium and cadmium, in the hospital effluent did not exceed standard concentrations. CONCLUSION: Micro-organisms exceeding standard levels were found in treated wastewater in two-thirds of the hospitals. Lead, chromium and cadmium levels in hospital effluent were in an acceptable range.

Problems and obstacles in implementation of nosocomial infection control in Thailand.

OBJECTIVES: To study the problems in implementation of nosocomial infection (NI) control in Thailand and strategies to overcome the obstacles. MATERIAL AND METHOD: Interviewing administrators, chair-persons of infection control committee and doctors. RESULTS: During June 2002 and August 2003, 255 persons were interviewed by infection control nurses using a set of questionnaires. Administrators, chair-persons of infection control committee, doctors in 32 hospitals across the country were enrolled by stratified random sampling. Policy on NI control was known to 95.3% and implementation to 81.2% of subjects. The main obstacles of NI control was the lack of incentive (66.7%) and support from administrators (30.2%). Hospital administrators set NI control at high priority, in only 40.9%, they could be motivated by regular presentation of NI data. Infection control nurses (ICN) should ideally work full-time (88.6%) but in reality, only 20.8% did so. The main problem for NI control was the shortage of ICN posts in most hospitals. This resulted in no career ladder and incentive for ICN. To overcome these problems, support from administrators, more education programs in NI control and provision of posts for ICN, are needed. CONCLUSION: The main problems and obstacles an implementation of NI control were the lack of support from administrators and the lack of the ICN post.